Dissertations / Theses on the topic 'Oils and fats, Edible'
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1
Aladedunye, Adekunle Felix. "Inhibiting thermo-oxidative degradation of oils during frying." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, 2011, 2011. http://hdl.handle.net/10133/3257.
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The present study sought for practical ways to improve the frying performance of
oils without compromising the availability of the essential fatty acids and nutraceuticals.
To this end, the influence of temperature, oxygen concentrations, and compositions of
minor components on frying performance was investigated.
A novel frying protocol, utilizing carbon dioxide blanketing, was developed and
found to significantly improve the performance of the frying oil. Optimizing both the
amounts and the compositions of endogenous minor components also improved the
performance of the frying oil.
Twenty one novel antioxidants were synthesized and evaluated under frying and
storage conditions. Antioxidant formulations consisting of a combination of endogenous
and synthesized antioxidants were developed and tested in an institutional frying
operation.
A rapid and effective frying test was developed to assess the frying performance
of oils and applied antioxidants. Furthermore, a novel procedure for direct
hydroxynonenal analysis in frying oil was developed.xx, 249 leaves; 29 cm
2
Zamani, Younes. "Determination of physical characteristics of food fats." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape10/PQDD_0007/MQ44324.pdf.
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Li, Hui 1970. "Analysis of edible oils by Fourier transform near-infrared spectroscopy." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36819.
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Fourier transform near-infrared (FT-NIR) spectroscopy was investigated as a means of quantitative analysis of edible fats and oils. Initially, a method of simultaneously determining the cis and trans content, iodine value and saponification number of neat fats and oils using a heated transmission flow cell was developed. Two partial least squares (PLS) calibrations were devised, a process-specific calibration based on hydrogenated soybean oil and a more generalized calibration based on many oil types, the latter able to analyze oils from a variety of sources accurately and reproducibly. Methodology for the quantitative determination of the peroxide value (PV) of edible oils using a novel glass-vial sample handling system was subsequently developed, based on the stoichiometric reaction of triphenylphosphine with hydroperoxides to form triphenylphosphine oxide. The PV calibration was derived using PLS regression, and the results of a validation study demonstrated that PV could be quantitated accurately if a normalization routine was used to compensate for the inherent dimensional variability of the vials. The vial sample handling system was then used in the development of PLS IV calibrations for the process analysis of commercial oil samples, and these samples were also used to evaluate a global IV calibration devised by Bomem Inc. The discriminant features available through PLS were shown to enhance the accuracy of the IV predictions by facilitating the selection of the most appropriate calibrations based on the spectral characteristics of closely related oils. The predictions obtained using the global IV calibration provided clear evidence that a generalized calibration based on a large and varied selection of oils could provide a means of IV determination by FT-NIR spectroscopy. Subsequently, a generalized FT-NIR trans calibration was developed and shown to yield trans values that were in good agreement with those obtained by the AOCS mid-FTIR single-bounce hori
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Lazarick, Kelsey. "Cause of color component formation in oils during frying." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, c2012, 2012. http://hdl.handle.net/10133/3303.
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Color formation in oils during frying is one of the most noticeable degradation
reactions that occur in the frying oil. Degradation reactions cause formation of products that positively and negatively impact the nutritional and sensory qualities of both the food being fried and the frying oil. The origins of these pigment forming reactions in the oil and the factors affecting these reactions are not well understood. Assessments of the mechanisms, the components involved and external conditions affecting oil darkening were conducted. The effect of basic food ingredients, commercially sold and laboratory formulated breading and battering, preformed lipid hydroperoxides and phospholipids on color formation and oil degradation of the frying oil were investigated.
Protein products, specifically whey protein, caused both the fastest darkening and
thermo-oxidative deterioration of the frying oil. This breakdown was aided further through
the addition of minor food materials such as glucose and amino acids as well as lipid
hydroperoxides in concentrations greater than 5 % of the frying oil. Nonenzymatic browning is the main reaction causing color formation in the frying oil and utilizes carbonyls from the food product such as starches, sugars and lipid oxidation products as starting materials alongside amino groups from proteins and amino acids. Breading ingredients contributed to oil color formation due to particles from the food crust breaking off into the frying oil to further accelerate browning reactions. Increasing the temperature of the frying oil provided additional stimulus for color forming and thermo-oxidative reactions to progress at a faster rate.xv, 184 leaves : ill. ; 29 cm
5
Rindt, Allyson. "Consumer acceptance of cranberry seed oil in several food formulations." Online version, 2008. http://www.uwstout.edu/lib/thesis/2008/2008rindta.pdf.
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Sedman, Jacqueline. "Application of Fourier transform infrared spectroscopy in the analysis of edible fats and oil." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36833.
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The application of Fourier transform infrared (FTIR) spectroscopy in the assessment of oil quality and stability and the determination of the degree and type (cis or trans) of unsaturation of fats and oils was investigated. FTIR spectroscopy was shown to provide a rapid means of monitoring changes in oils undergoing oxidation or subjected to thermal stress. Absorption bands associated with common primary and secondary oxidation products were identified by relating them to those of spectroscopically representative reference compounds, and a quantitative approach based on the use of oils spiked with these reference compounds as calibration standards was proposed. A sample-handling accessory based on a heated 25-mum transmission flow cell and heated input and output lines was developed to facilitate the rapid analysis of oils and premelted fats in their neat form. Using this system, an FTIR edible oil analysis package was developed to simultaneously analyze for trans content, cis content, iodine value (IV), and saponification number (SN) of neat fats and oils, using partial-least-squares (PLS) calibrations based on pure triglycerides. An automated transmission-based peak height method for isolated trans isomer determination using the characteristic trans absorption band at 967 cm -1 in the spectrum of a neat fat or oil, ratioed against the spectrum of a trans-free oil, was also developed. A subsequent validation study involving the analysis of more than 100 oil samples demonstrated concurrence between the trans data obtained by the PLS and peak height FTIR methods as well as between IV results obtained by FTIR analysis and gas chromatography. In addition, the internal consistency of the IV, cis, and trans FTIR predictions provided strong experimental evidence that the FTIR edible oil analysis package measures all three parameters accurately. A PLS-based IV/trans method was developed for a heated single-bounce horizontal attenuated total reflectance (SB-HATR) sample-
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Cash, Gregory Anthony. "Studies of the oxidation and stabilisation of vegetable oils and model compounds." Thesis, Queensland University of Technology, 1986. https://eprints.qut.edu.au/35985/1/35985_Cash_1986.pdf.
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This thesis describes the use of a novel chemiluminescence (CL)
technique to deter·mine the extent of oxidation and stability in
both model compounds and vegetable oils. As it is the presence
of hydroperoxides in vegetable oils that leads to theirdeterioration,
the hydroperoxides of methyl linoleate (MU were
used as model compounds in a CL study of hydroperoxide
decomposition in nitrogen, both in the bulk and on active
substrates. The largest signals and the fastest decays
occurred on neutral alumina. The results indicate induced
decomposition via a bimolecular initiation of hydroperoxides
adsorbed on adjacent active sites. The majority of these
hydroperoxides are vertical to the surface, being bound to the
alumina through the ester group only.
A relationship was found between hydroperoxide concentr·ation
and initial intensity when the methyl linoleate hydroperoxide
was adsorbed on neutral alumina. Solutions of natural and
arti-ficial antioxidants in ML were studied. Some solutions
gave changes in kinetics. These changes suggest that the
antioxidant itself may contribute to the CL. The method of
inhibitors was used to find the rate of initiation and
hydroperoxide level in ML at 80c:>C.
The spectral distribution of CL was determined for model
compounds, antioxidants and vegetable oils. In the presence of
antioxidants ther-e was a shift towar-d the r-ed end of the
spectr-um. In model compounds, the CL was most likely due to an
excited triplet state ketone and this is consistent with the
mechanism for- ter·mination of alkyl peroxy r-adicals.
The techniques developed for the model compounds were extended
to the mor-e complex vegetable oils. Unrefined and deliberately
damaged vegetable oils were studied at 80c:>C on neutral
alumina. CL examination of these oils in nitr-ogen was able to distinguish between some damaged and undamaged oils.
Conjugated diene levels did not correlate well with CL results.
0<-tocopherol and a-carotene were found to be chemiluminescent
on alumina and their presence in unr·efined oil may inter·fer·e
with CL assessment.
The method of inhibitors, when applied to a vegetable oil
sample, permitted the determination of both hydroperoxide
concentration and the level of natural antioxidant alr-eady
present in the oil.
ii
8
Midson, Kerri. "Comparative deterioration of frying oil due to different heat exchangers /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe17848.pdf.
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Memon, Khalida Perveen. "Solid fat index determination by Fourier transform (FTIR) spectroscopy." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=24028.
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This work describes an investigation of the development of a Fourier Transform Infrared (FTIR) spectroscopic method for the determination of Solid Fat Index (SFI) of fats as a possible replacement of the traditional dilatometric procedure. The initial approach considered was the use of an existing FTIR analytical package which was designed to measure iodine value (IV), saponification number (SN), and cis and trans content. It was hypothesized that these measures could be related to SFI using multiple linear regression (MLR), thereby allowing the existing analytical package to simultaneously make SFI measures. It was found that there was a strong relationship between SN/cis/trans measurements and SFI, especially in sequentially hydrogenated oils. The MLR relationships, however, did not reproduce the dilatometric SFI values with sufficient accuracy in the general case, and this approach had to be abandoned. Subsequently, a partial least squares (PLS) calibration approach was investigated, relating the dilatometric SFI data directly to the spectral characteristics of the melted fats. It was found that suitable PLS calibrations could be developed for soybean and Canola oils. Based on these results, an FTIR system was programmed to determine SFI and the performance of the system validated using pre-analyzed "unknowns". It was shown that the SFI of either soybean or Canola oils could be determined to within $ pm$ 1.0 SFI. As configured, the FTIR system is capable of determining the SFI of a neat and clear, melted fat sample at 80$ sp circ$C in less than two minutes, providing four SFI values, representing the solids content at 50, 70, 80 and 92$ sp circ$F. In contrast to the standard dilatometric method, which takes over two hours to carry out, the FTIR approach provides a rapid means of determining SFI, the technique being suitable for routine quality control applications in the fats and oils industry.
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Robertson, Katherine Anne. "Effect of flour protein content on the utilization of shortening and cellulose in biscuits." Thesis, Virginia Tech, 1988. http://hdl.handle.net/10919/45172.
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Biscuits were prepared from eighteen different recipe formulations. The biscuits were made from flour containing 7.53%, 8.99%, and 10.05% protein with 30, 40, and 50 grams of shortening and 0 or 2.2 grams of microcrystalline cellulose (MCC). Biscuit quality was assessed by objective and sensory evaluation. The caloric content of the biscuits was also determined by bomb calorimetry.
No significant differences were detected in biscuit volume, crumb and crust color, or tenderness. The biscuits prepared with lower levels of shortening were moister than the biscuits prepared with higher levels of shortening. Wo significant differences were found by sensory panelists with regard to evenness of exterior color, aroma, evenness of cell structure, size of cell structure, interior color, center moistness, tenderness, biscuit flavor, or aftertaste. Flakiness and exterior color were found to be significantly different. Biscuits with added MCC were detected to be less flaky. Biscuits prepared from medium protein level flour and low-shortening with MCC were darker than high-shortening biscuits without MCC. High-protein, high-shortening biscuits with MCC were darker than medium-protein, high-shortening biscuits without MCC. The caloric content of the biscuits prepared with lower amounts of shortening was found to be significantly less than biscuits prepared with the higher levels of shortening. In conclusion, high quality biscuits can be produced from flour of varying protein content with less shortening and without the incorporation of MCC.Master of Science
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Bati, Nabil A. "Thermal, oxidative and hydrolytic stability of selected frying shortenings evaluated by new and conventional methods." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54488.
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The thermal, oxidative, and hydrolytic stability of several frying shortenings were studied via chemical, physical and sensory analyses. Corn, cottonseed and peanut oils, and cottonseed and soybean liquid shortenings were tested under static heating conditions, while peanut oil, and cottonseed and soybean oil liquid shortenings were evaluated under commercial frying conditions.
The research had two objectives: to evaluate the relative stability of the various shortenings under both heating condition; and to evaluate new or modified quality assessment methods which would provide early prediction of heat abuse for the fast-food industry.
Six of the conducted analyses were conventional or modified: free fatty acids; polar components; gas chromatograph volatile profiles; viscosity; FoodOil-Sensor; and sensory. Three were new: contact angle; high temperature; and high-temperature gas chromatographic analysis of triglyceride; and polar component % as determined by high-performance thin-layer chromatography (HPTLC).
Under static heating conditions, varying heating periods or shortening types had significant (P<0.000l) effects on the resulting data of the following tests: free fatty acids; polar component; total volatiles; dielectric constant; viscosity; polar component % measured by HPTLC; contact angle; and sensory analysis; but heating time had no significant effect on triglyceride profiles
Under commercial frying conditions of chicken nuggets and filets, heating time had significant effects on changes in the dielectric constant; free fatty acid %; viscosity; contact angle; and sensory rating; also it had a significant effect on the polar component % under chicken nugget frying conditions only. Furthermore, heating time had no significant effect on polar component % under chicken filet frying conditions and on polar component % by HPTLC under both frying conditions
Cottonseed oil liquid shortening had sensory scores equal to peanut oil under static and commercial frying conditions even though peanut oil exhibited a greater chemical and physical stability. Soybean oil liquid shortening had an objective quality identical to peanut oil, however, its subjective quality was lower. Cottonseed oil liquid shortening had better flavor but less objective stability than soybean oil liquid shortening
The cut-off quality level for the shortenings was not reached, because all the shortenings were discarded after seven days of use which was before the onset of significant-quality deterioration.
The best on-site index of shortening stability was the FoodOil-Sensor reading (dielectric constant) which was followed by the free fatty acid test.Ph. D.
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Mottram, Hazel Rosemary. "The application of HPLC-APCI MS to the regiospecific analysis of triacylglycerols in edible oils and fats." Thesis, University of Bristol, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285582.
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朱翠珊 and Tsui-shan Chu. "Factors affecting the structure and oil content of steamed-and-fried instant noodles." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B31222511.
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Schoeman, Mathilda Elizabeth. "Mango (Mangifera indica L.) kernel fat : fatty acid profile, oxidative stability and development of fourier transform near infrared (FT-NIR) spectroscopy calibration models." Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52925.
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Thesis (MSc Food Sc )--Stellenbosch University, 2002.ENGLISH ABSTRACT: The oxidative stability of crude, cold-pressed mango kernel fat (MKF) was determined over a period of 240 days using the peroxide value (PV), conjugated diene value (CD) and p-anisidine value (AV) tests. The changes in fatty acid profile were monitored with gas chromatography and the oxidative status of MKF effectively predicted by FT-NIR spectroscopy. Results obtained from the different methods complemented each other and indicated the stable character of mango kernel fat against oxidative deterioration. The fatty acid profile constituted palmitic acid (CI6:0; 8.43%), stearic acid (CI8:0; 34.98%), oleic acid (CI8:1 cis; 48.05%), linoleic acid (CI8:2; 6.60%) and arachidic acid (C20:0; 1.73%). Trace amounts of C16:1 (0.56%), C18:1 trans (0.25%), C18:3 (0.43%), C20:1 (0.25%) and C22:0 (0.40%) were also found. The freshly pressed MKF had a peroxide value of 2.7 meq.kg", CD value of 0.07% and an AV of 2.2 mmol.kg", After 40 days of storage, the peroxide values of MKF stored with and without exposure to a limited amount of oxygen at 5, 15,25 and 40°C increased to 5 meq.kg" and 4 meq.kg" respectively. Emulsification of MKF had a stabilising effect (maximum PV = 2.8 meq.kg'), while exposure to UV light had a catalysing effect (maximum PV = 5 meq.kg'). These maximum values, decreased after 40 days. The CD values of MKF samples stored with and without exposure to oxygen at 5, 15,25 and 40°C increased to 0.18% and 0.16%, respectively at day 40. The CD values of samples exposed to light increased to 0_20% and the emulsified samples showed similar values to that of the MKF samples not exposed to oxygen. The conjugated diene values remained stable after day 40. The p-anisidine values of the MKF samples both stored with and without exposure to oxygen at 5, 15, 25 and 40°C varied between 0.5 and 5 mmol.kg". The weak correlation to the measurement of nonanal, as well as the low levels of 2-alkenals produced by the MKF, resulted in these low and sometimes non-linear values. The peroxide, conjugated diene and p-anisidine values obtained for MKF stored at 25°C over 240 days were low due to the low content of polyunsaturated fatty acids in MKF. This compared favourably with the higher values attained for sunflower, canola and olive oil, which are all rich in polyunsaturated fatty acids. The minimal changes observed in the fatty acid profile of mango kernel fat indicated the stability of the saturated fatty acids (CI6:0 and CI8:0) and oleic acid. In addition, the instability of linoleic and linolenic acids was evident due to oxidative deterioration. A decrease of 7.41% and 12.80% was observed between day 0 and 240 for the C18:2/C16:0 and C18:2/C18:0 ratios respectively. The prediction of the oxidative status of the MKF samples by near infrared spectroscopy were possible after the development of calibration models from a total data set of 300 samples of which one-third was used for independent validation. Principle component analysis (PCA) indicated classification at 0, 40 and the remaining (80 - 240) days. The best calibration model for PV yielded a SEP (standard error of prediction) of 0.46 meq.kg", correlation coefficient (r) of 0.95, bias of 0.02 and a root mean square error of prediction (RMSEP) of 0.46 meq.kg". The CD calibration model had a correlation coefficient of 0.89, SEP of 0.01 %, bias of 0.001 and RMSEP of 0.01% when developed on a data set with no pre-processing applied. The AV calibration had a SEP of 0.32 mmol.kg", bias of 0.03, RMSEP of 0.32 mmol.kg" and rof 0.93. The C18:2 and C18:3 models were built using partial least squares (PLS) regression and the values obtained for SEP were 0.31% and 0.054%, RMSEP 0.32% and 0.05%, bias 0.05 and 0.01 and correlation coefficcients were 0.82 and 0.54 respectively. The calibrations for CI8:1, C18:0 and C16:0 yielded weaker correlations. Good correlations were obtained when calibrating the CI8:2/CI6:0 and C18:2/CI8:0 ratios.
AFRIKAANSE OPSOMMING: Die oksidatiewe stabiliteit van ru, koud-geperste mango kern vet (MKV) (Mangifera indica L.) is oor 'n periode van 240 dae bepaal deur gebruik te maak van die peroksiedwaarde (PV), gekonjugeerde dieen waarde (CD) en p-anisidien waarde (AV) toetse. Die veranderinge in die vetsuurprofiel is gemonitor deur gaschromatografie en die oksidatiewe status van MKV is akkuraat voorspel word deur Fourier transformasie naby infrarooi (FT-NIR) spektroskopie. Die resultate van die verskillende toetsmetodes komplementeer mekaar goed en dui die stabiliteit van mango kern vet teen oksidatiewe verval aan. Die vetsuurprofiel is saamgestel uit palimitiensuur (C16:0; 8.43%), steariensuur (C18:0; 34.98%), oleïensuur (C18:1 cis; 48.05%), linoleïensuur (C18:2; 6.60%) en aragiedsuur (20:0; 1.73%). Spoorhoeveelhede C16:1 (0.56%), C18:1 trans (0.25%), C18:3 (0.43%), C20:1 (0.25%) en C22:0 (0.40%) is ook geïdentifiseer. Die vars geperste MKF het 'n peroksiedwaarde van 2.7 meq.kg", 'n CD waarde van 0.07% en 'n AV waarde van 2.2 mmol.kg" getoon. Na afloop van 40 dae opbergingsperiode by 5, 15, 25 en 40°C het die PV van MKV met 'n beperkte blootstelling aan suurstof na 5 meq.kg" vermeerder, terwyl die waardes van monsters sonder suurstofblootstelling na 4 meq.kg" vermeerder het. Emulsifisering van MKV het 'n stabiliserende effek (maksimum PV = 2.8 meq.kg") terwyl blootstelling aan ultraviolet (UV) lig 'n kataliserende effek (maksimum PV = meq.kgl ) op oksidasie gehad het. Hierdie maksimum waardes het na 40 dae afgeneem. Die CD waardes van MKF monsters opgeberg by 5, 15, 25 en 40°C en met beperkte blootstelling aan suurstof het vermeerder tot 0.18% terwyl die monsters sonder suurstofblootstelling by bogenoemde temperature vermeerder het tot 0.16% na 40 dae. Die gekonjugeerde dieen waardes van die monsters blootgestel aan UV lig het vermeerder tot 0.20%; terwyl die geëmulsifiseerde monsters waardes soortgelyk aan die MKV monsters sonder blootstelling aan suurstof getoon het. Gekonjugeerde dieen waardes het gestabiliseer vanaf dag 40. Die p-anisidienwaardes van MKV monsters opgeberg by temperature van 5,15, 25 en 40°C, met en sonder blootstelling aan suurstof, het varieer tussen 0.5 en 5 mmol.kg". Die swak korrellasie tussen nonanal produksie en p-anisidienwaardes, sowel as die klein hoeveelhede 2-alkenale geproduseer, was verantwoordelik vir hierdie lae en nie linêere waardes. Die peroksied, gekonjugeerde dieen en p-anisidienwaardes wat verkry is nadat MKV by 25°C in 240 opgeberg is, was laag weens die klein persentasie poli-onversadigde vetsure teenwoordig in die vet. Dit vergelyk goed met die hoë waardes wat verkry is vir sonneblom-, canola- en olyfolie wat almal ryk aan poli-onversadigde vetsure is. Die minimale veranderinge in die vetsuurprofiel van MKF dui op die stabiliserende invloed van versadigde vetsure (C16:0 en C18:0) en oleïensuur. Die onstabiliteit van linoleïen- en lineensuur duidelik uit hierdie vetsure se oksidatiewe verval. 'n Afname van 7.41% en 12.80% is waargeneem tussen dae 0 en 240 vir die C18:2/C16:0 en C18:2/C18:0 verhoudings, onderskeidelik. Die voorspelling van die oksidatiewe status van die MKF monsters met behulp van FT-NIR spektroskopie was moontlik deur die ontwikkeling van kalibrasie modelle. 'n Totale datastel van 300 monsters, waarvan ongeveer 'n derde vir validasie aangewend is, is gebruik vir die kalibrasiemodelle. Met behulp van PCA (hoojkomponent analise) kon drie klassifiseerbare groepe by 0, 40 en 80-240 dae onderskei word. Die beste kalibrasiemodel vir PV het 'n standaardfout van voorspelling (SEP) van 0.46 meq.kg", 'n korrellasiekoëffisient (r) van 0.95, 'n oorhelling van 0.02 en 'n standaardfout van voorspelling (RMSEP) van 0.46 meq.kg" gehad. Die CD kalibrasiemodel (geen voorafverwerking) het 'n r van 0.89, SEP van 0.01% oorhelling van 0.001 en RMSEP van 0.01% gehad. Die AV kalibrasie het 'n SEP van 0.32 mmol.kg', oorhelling van 0.03, RMSEP van 0.32 mmol.kg" en r van 0.93 gehad. Die C18:2 en C18:3 modelle is saamgestel deur PLS (partial least squares) regressie. Waardes verkry vir C18:2 en C18:3 was onderskeidelik: SEP 0.32% en 0.05%, RMSEP, 0.32% en 0.05%, oorhelling 0.05 en 0.01 en r 0.82 en 0.54. In die geval van C18:1, C18:0 en C16:0, het die kalibrasies swakker statistiek korrellasies getoon. Goeie korrellasies is verkry tydens kalibrasie vir die C18:2/C16:0 en C18:2/C18:0 verhoudings.
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Chu, Tsui-shan. "Factors affecting the structure and oil content of steamed-and-fried instant noodles /." Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22053955.
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Kamm, Willibald. "Authenticity control of edible fats and oils by analysis of minor constituents via on-line liquid chromatography - gas chromatography." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965254364.
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Al-Alawi, Ahmed Ali. "Novel approaches to automated quality control analyses of edible oils by Fourier transform infrared spectroscopy : determination of free fatty acid and moisture content." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=100311.
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Three new quantitative Fourier transform infrared (FTIR) spectroscopic methods were developed for the analysis of edible oils: two procedures to measure free fatty acids (FFA) and one to measure moisture (H2O), the latter two methods ultimately being automated and implemented on an auto-sampler equipped FTIR spectrometer. The methods developed for FFA determination both convert FFAs to their carboxylate salts by means of acid/base reaction without causing oil saponification, one approach using 1-propanol, an oil-miscible solvent, and the other using methanol, an oil-immiscible solvent into which the FFA salts are extracted. The first method involves splitting oil samples into two halves, with one half treated with propanol containing base and the other half with propanol only. The spectra of each half is collected and a differential spectrum obtained, from which quantization is performed. The methanol procedure simply involves extracting FFA into methanol containing a weak base and quantitating the FFA salts produced. Both FFA methods determine the FFA content by measuring the v (COO-) absorbance at ∼1570 cm-1 relative to a reference wavelength of 1820 cm-1 from a differential spectrum relative to the solvent, the extraction procedure being superior in terms of both speed and sensitivity, being able to measure FFA levels down to ∼0.001%. The method developed for moisture determination involves extracting water in edible oils into dry acetonitrile and then quantitating it by measuring the absorbance of the OH stretching band (3629 cm-1) and/or the HOH bending band (1631 cm -1). All three methods were validated by standard addition experiments, evaluated for potential interferences, and, in the case of FFA determination, compared to the performance of AOCS official methods. The results indicated that the extraction-based procedures were superior to conventional wet chemical methods in both sensitivity and reproducibility. The FFA and H2O extraction procedures were subsequently automated by connecting an auto-sampler to the FTIR spectrometer and developing procedures and software algorithms to enable the analysis of up to 100 samples/h. The methods developed and implemented are a substantive improvement over conventional methods for the analysis of FFA and H2O in edible oils and provide a means by which QC and process laboratories can analyze large volumes of edible oils for these two important parameters.
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Cha, Ming Chuan 1955. "Effects of dietary fat selection and energy restriction on tissue lipid metabolism : structure, function and regulation." Thesis, McGill University, 1998. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=35684.
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To investigate interactive effects of dietary fatty acid composition and energy restriction on body lipid metabolism and its regulation, rats were fed for 10 weeks diets varying in fat type and energy intake level. Energy deficiency was achieved by removing carbohydrate from the diets while keeping fat and other nutrient intakes constant. Tissue fatty acid deposition was influenced by the interaction between the dietary fat source and body energy balance. Less total fatty acids were deposited in livers of the ad libitum beef tallow-fed animals than the other fat feedings. However, such difference no longer existed when energy intake was restricted. Similarly, less energy supply eliminated the higher docosahexaenoic acid and lower arachidonic acid contents associated with the fish oil feeding in hepatocyte membrane phosphatidylchohne, phosphatidylserine and sphingomyelin. Tissue lipogenesis was also examined as a function of the interaction of dietary fatty acid composition and energy restriction. Comparable absolute cholesterol synthesis rates were observed in livers of the food restricted animals fed different types of dietary fat, although the synthesis rates were different among the dietary fat groups fed ad libitum. Energy restriction increased the triglyceride-fatty acid synthesis rates in the intestine of the fish and safflower oil-fed groups, but not in that of the olive oil- and beef tallow-fed animals. Plasma leptin concentrations were 60% higher in the ad libitum-fed fish and safflower oil groups as compared with those in the beef tallow diet group, despite smaller perirenal fat mass and fat cell size in the fish oil-fed animals. Energy restriction decreased plasma leptin levels of the fish and safflower oil-fed rats, but not those in the beef tallow-fed animals. Taken together, these results demonstrate that the structural, functional and regulating aspects of tissue lipid metabolism were influenced by an interaction between dietary fatty acid composit
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Russin, Ted Anthony. "A novel and rapid method to monitor the autoxidation of edible oils using Fourier transform infrared spectroscopy and disposable infrared cards /." Thesis, McGill University, 2002. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=79119.
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A novel and rapid method was developed to monitor the autoxidation of edible oils by Fourier transform infrared (FTIR) spectroscopy with the use of disposable polymer infrared (PIR) cards having a microporous polytetrafluoroethylene (PTFE) sample substrate. Under conditions of mild heating (~58°C) and aeration, both model triacylglycerols (TAGS) and edible oils applied onto the PIR cards underwent rapidly accelerated oxidation. In order to compare the oxidative stability of samples on the PIR cards in terms of the time required to reach a peroxide value (PV) of 100 mequiv/kg oil, matching the end-point measured in the standard active oxygen method (AOM), an absorbance slope factor (ASF) was determined to relate changes in hydroperoxide (ROOH) absorbance (peak maximum found within the range of 3500--3200 cm-1 ) to PV. Similar ASF values were found for the four edible oils tested (safflower, canola, sunflower, and extra virgin olive oil), permitting determination of a pooled, universally applicable ASF value of 0.0526 mAbs/PV.
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Dubois, Janie. "Determination of peroxide value and anisidine value using Fourier transform infrared spectroscopy." Thesis, McGill University, 1995. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=23391.
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Lipid oxidation has important consequences in the edible oil industry, producing compounds with sensory impact and thus reducing the economic value of the products. This work focused on the development of two Fourier transform infrared (FTIR) spectroscopy methods for the measurement of peroxide value (PV) and anisidine value (AV), representing the primary and secondary oxidation products of edible oils.The infrared method developed for PV determination was based on a mathematical treatment by the partial least squares method of the information contained in the spectral region between 3750 and 3150 cm$ sp{-1}$.
The second method developed considered aldehyde content and anisidine value, a measure of secondary oxidation products.
The two methods developed are rapid ($ sim$2 min/sample) and have the advantage of being automatable. An infrared system coupled to a computer can collect the spectrum of an oil, analyze it and present a report without the need for personnel trained in FTIR spectroscopy. The cost of such a system would rapidly be absorbed through savings on personnel cost, time and chemical reagents required for conventional chemical methods and as such provides a useful advance in quality control methodology for the edible oils sector. (Abstract shortened by UMI.)
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Ma, Kangming 1965. "Peroxide value and trans analyses by Fourier transform infrared (FTIR) spectroscopy." Thesis, McGill University, 2000. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=36643.
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New Fourier transform infrared (FTIR) approaches for the quantitative determination of peroxide value (PV) and isolated trans analyses were investigated and developed. The FTIR-PV methods investigated were all based on the stoichiometric reaction of hydroperoxides and triphenylphosphine (TPP) which converts TPP to triphenylphosphine oxide (TPPO). A reference transmission cell (100 mum) method was developed based on the use of a unique TPPO absorption at 542 cm-1. This method covered PV values from 0--15 PV and was shown to be superior in accuracy and reproducibility to the standard American Oil Chemists Society (AOCS) iodometric method. Subsequently, the utility of disposable polyethylene cards, normally used only for qualitative analyses, was investigated for quantitative PV determination. A quantitative IR card method was successfully developed and shown to serve as a very simple, rapid and alternative means of carrying out PV analyses. TPP-impregnated cards were able to reproduce the transmission cell PV results to +/-1.12 PV, while the unimpregnated card was slightly more accurate (+/-0.92 PV). A third FTIR-PV method was developed specifically for the at-line monitoring of high PV fatliquors and employed a germanium attenuated total reflectance sample handling accessory. This method hinged on the use of a TPPO absorption band at 1118 cm-1, normally off scale when pathlengths of >3 mum are used, but is suited to the analysis of oils having very high PVs (>250). The successful quantitative use of the disposable polyethylene IR card to PV led to its study for the quantitative FTIR determination of the isolated trans content of fats and oils and margarines. The polyethylene card was shown to unique and useful properties, tending to inhibit fat crystallization and its inability to retain moisture. These two properties allowed trans determination to be carried out on melted, high trans fats, without heating the polyethylene substrate and also to analyze margarines
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Birkel, Emily Ann. "Application of a Portable Handheld Infrared Spectrometer for Quantitation of trans Fat in Edible Oils." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1305305940.
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Muniz, Adriana. "Efeito da adição do óleo de soja, óleo de linhaça, óleo de coco babaçu e sebo bovino nos parâmetros produtivos e reprodutivos de fêmeas suínas em lactação." Universidade de São Paulo, 2004. http://www.teses.usp.br/teses/disponiveis/10/10131/tde-28082007-095434/.
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O objetivo do experimento foi verificar o efeito da adição do óleo de soja, óleo de linhaça, óleo de coco babaçu e sebo bovino na ração de fêmeas suínas lactantes. As dietas eram energeticamente altas, sendo uma dieta basal acrescida em 8% por diferentes fontes de energia, (1) óleo de soja, (2) óleo de linhaça, (3) óleo de coco e (4) gordura animal, tratamentos 1, 2, 3 e 4 respectivamente. O experimento foi realizado na Fazenda Santa Rosa, Leme, SP. As variáveis avaliadas foram peso inicial, aos 100 dias de gestação (PI), peso à desmama (PD), espessura de toucinho aos 100 dias de gestação (ETI), espessura de toucinho à desmama (ETD), mudanças corporais no período lactacional como perda de peso (PP), perda de espessura de toucinho (PET), produção de leite (PL) e peso dos leitões (Ple) nos dias 7, 14 e 21 da lactação, intervalo desmama estro (IDE), duração do estro (DE) e concentrações de estrógeno (Es) à desmama, 48 horas após a desmama e no estro. A espessura de toucinho foi medida no P2. A técnica de PL foi realizada pela técnica de peso dos leitões antes e depois das mamadas. O manejo para diagnóstico do estro foi realizado duas vezes ao dia. As coletas de sangue foram realizadas em 3 ocasiões à desmama (Dia 1), 48 horas após a desmama (Dia 2) e na comprovação do estro (Dia 3). As análises da (Es) foram realizadas pela técnica de radioimunoensaio. Foram utilizadas 24 fêmeas, em um delineamento inteiramente ao acaso. Os resultados foram analisados através do programa computacional Statistical Analysis System (SAS Institute Inc., 1985) submetidos à análise de variância pelo procedimento GLM (PROC GLM). Para os valores de peso, espessura de toucinho, bem como das mudanças no período não houve diferença significativa, e os resultados foram para PI 257,7; 259,3; 265,0 e 267,0 quilos e para PD 231,3; 217,4; 224,9 e 225,0 quilos para os tratamentos 1, 2, 3 e 4, respectivamente. Os valores de 17,0; 16,5; 16,5; 16,0 milímetros foram para ETI e 13,2; 12,13; 12,5 e 12,0 mm para ETD nos tratamentos 1, 2, 3 e 4, respectivamente. A PP durante a lactação foi de 44,4; 41,9; 40,1 e 39,1 para os tratamentos 1, 2, 3 e 4, respectivamente. Já a PET apresentou médias de 3,8; 4,2; 4,0 e 4,0 mm nos tratamentos 1, 2, 3 e 4, respectivamente. Não foi encontrada diferença significativa para PL, bem como para os diferentes dias de mensurações tendo como resultados no 7º dia 10,13; 9,43; 8,98 e 8,85 Kg para os diferentes tratamentos 1, 2, 3 e 4, respectivamente. No 14º dia os valores médios para os tratamentos foram de 10,12; 11,20; 10,26 e 8,79 Kg, respectivamente, e os valores de 11,34; 10,47; 10,56 e 10,76 Kg para os tratamentos 1, 2, 3 e 4, respectivamente para o 21º dia. O peso dos leitões não foi significativo entre os tratamentos, mas apresentou significância nos três diferentes tempos (P < 0,01) e os valores médios foram de 2,87; 2,95; 2,83 e 2,9 Kg para os tratamentos 1, 2, 3 e 4, respectivamente para o 7º dia de amamentação, de 5,01; 4,88; 4,8 e 4,75 Kg nos tratamentos 1, 2, 3 e 4, respectivamente para 14º dia. Já para o 21º dia os valores nos tratamentos 1, 2, 3 e 4, respectivamente foram de 6,80; 6,58; 6,56 e 6,82 Kg. O IDE e DE não apresentaram diferença significativa e tiveram como médias nos respectivos tratamentos 1, 2, 3 e 4 de 74,0; 68,0; 70,3 e 78,7 horas para IDE e 57,6; 62,0; 64,0 e 72,0 para DE. Para as médias de Es não houve significância e estas apresentaram os seguintes valores de 10,25; 12,82; 9,65 e 8,71 pg/ml nos respectivos tratamentos 1, 2, 3 e 4 no dia 1. Para o dia 2 os valores nos tratamentos 1, 2, 3 e 4 foram de 25,8; 27,39; 24,64 e 32,12 pg/ml respectivamente, e os valores de 83,6; 79,14 e 77,64 pg/ml para os tratamentos 1, 2, 3 e 4, respectivamente referentes ao dia 3.Twenty-four Dalland C40 sows were used in one experiment to study the effect of dietary vegetable oil or tallow on productive and reproductive parameters. All sows were fed a corn-soybean meal diet supplemented with 8% soybean (T1), linseed (T2), coconut (T3) oil or tallow (T4) from day 100 of gestation and throughout the lactation period. Sow initial weight and backfat thickness were determined at day 100 of gestation (ISW and IBT, respectively), and at weaning (WSW and WBT, respectively). Sow weight and backfat thickness losses (WL and BTL, respectively) were calculated, and milk yield (MY) was estimated at day 7, 14 and 21 of lactation by weighing the litter before and after suckling. Interval weaning estrus (IWE), and estrus duration (ED), and piglet weight (PW) were recorded. Blood samples were taken at weaning (day 1), and 48 hours after weaning (day 2), and at onset of estrus (day 3) for estradiol (E2) determination. There were no treatment effects for the parameters studied. The means for E2 were 10.25; 12.82; 9.65 e 8.71 pg/ml (day 1), and 25.8; 27.39; 24.64 e 32.12 pg/ml (day 2), and 83.6; 79.14 e 7764 pg/ml (day 3) for treatment 1, 2, 3 e 4, respectively. Means for E2 on day 3 were higher than values observed on day 1 and 2.
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López, Sabater María del Carmen. "Evolución de los parámetros químicos del aceite a lo largo de la maduración de las aceitunas del Montsiá." Doctoral thesis, Universitat de Barcelona, 1985. http://hdl.handle.net/10803/673081.
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Cataluña es una zona con una producción considerable de aceite de oliva (aproximadamente 17.500 toneladas anuales). Sin embargo, posee unas características de producción y/o elaboración muy variables según la comarca considerada, lo cual hace que los aceites producidos tengan una calidad diferente. En realidad, podemos considerar la existencia de tres zonas productoras, Les Garrigues (Borges Blanques), Siurana y Baix Ebre-Montsià, teniendo las dos primeras la Denominación de Origen correspondiente, caracterizada por un monocultivo de la variedad Arbeguina. La zona de Baix Ebre-Montsià se caracteriza, al contrario de las anteriores, por el cultivo de tres variedades (Farga, Sevillenc y Morrut) aunque, con carácter minoritario, se cultivan otras. Este hecho, junto con diferentes factores de tipo sociológico, métodos de recolección y elaboración poco actualizados, hace que, a pesar de ser la zona con mayor producción, la calidad final del aceite tenga unas características muy variables. Estos son los motivos que nos han inducido a concretar el estudio en esta zona, con el fin de colaborar en la mejora de calidad de los aceites.
La legislación relativa a los aceites vegetales comestibles ( B.O.E. de 29-2-83) es cada vez más estricta, lo cual implica que los aceites vírgenes elaborados en el Montsià, no puedan ser comercializados como tales, sino que normalmente se destinan para la elaboración de aceites de oliva "puros" o incluso "refinados”. De lo dicho anteriormente, se deduce un primer objetivo del trabajo, estudiar desde un punto de vista químico las características de estos aceites para poder concluir cuáles son algunos de los factores que inciden negativamente sobre la calidad de los mismos.
Para ello es preciso conocer, en primer lugar, las diferencia= entre las distintas variedades de aceitunas, tanto en los componentes mayoritarios (ácidos grasos), como compuestos minoritarios (componentes del insaponificable ),
De esta forma, se reúnen los objetivos principales de este trabajo, es decir, conocer las características de las distintas variedades de aceitunas, establecer de qué forma evolucionan los diferentes parámetros de calidad e incluso los componentes minoritarios a lo largo del proceso de maduración, con el fin de establecer el punto óptimo de recolección y llegar a definir, si es posible, los parámetros que permitan tipificar las diferentes variedades de aceituna.
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Milligan, Alex Michael. "Application of Mid-Infrared Spectrometers in Determination and Quantification of Trans-fatty Acid Content in Snack Foods and Bakery Products." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1398786873.
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Quast, Leda Battestin. "Estudo do efeito da adição de gorduras alternativas na cristalização da manteiga de cacau." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266281.
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Orientadores: Theo Guenter Kieckbusch, Valdecir LuccasTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: A influência da incorporação de gorduras alternativas low e zero trans na cristalização da manteiga de cacau foi avaliada através da caracterização física de misturas binárias de manteiga de cacau com gordura de cupuaçu, gordura CBR low trans e gordura CBS, nas proporções de 5, 10, 15, 20, 25 e 30 %. O processo de pré-cristalização (temperagem) foi realizado em um reator encamisado de escala piloto dotado de um agitador e com capacidade para 700 mL. As amostras foram caracterizadas através da curva de sólidos, tensão de ruptura (snap test), calorimetria diferencial de varredura e difração de raios-X. A melhor condição de pré-cristalização da manteiga de cacau pura (taxa de resfriamento de 1,8 ºC/min, cristalização à 24 ºC por um tempo de 8 minutos) também foi utilizada nos ensaios com as misturas, com exceção das amostras com 20, 25 e 30 % de CBR e CBS que foram pré-cristalizadas a 23 ºC por 10 minutos. A manteiga de cacau apresentou um perfil de fusão de gordura na boca, DS(25ºC-35ºC), de 59,2 %, que sofreu apenas pequenas alterações com a adição de até 20 % de cupuaçu e até 30 % de CBR. A curva do conteúdo de sólidos sugere a formação de um eutético entre a manteiga de cacau e a gordura CBS. A tensão de ruptura para a manteiga de cacau foi de 2,48 kgf/cm2 e a adição das gorduras tende a diminuí-la, sendo que com 30 % de cupuaçu e 30 % de CBR esse valor foi 1,90 kgf/cm2 e 1,81 kgf/cm2, respectivamente. Para a amostra com 30 % de CBS a tensão de ruptura baixou para 0,39 kgf/cm2. Observou-se uma diminuição do ponto de fusão das misturas quando comparadas à da manteiga de cacau pura. A difração de raios-X identificou a forma cristalina b como predominante para a manteiga de cacau e para a gordura de cupuaçu enquanto que para as gorduras CBR e CBS a principal forma cristalina é a b'. A incorporação de apenas 10 % das gorduras CBR e CBS à manteiga de cacau promoveu interferências na estruturação cristalina das amostras. O estudo indicou ser possível adicionar até 30 % de gordura de cupuaçu ou CBR e até 10 % de gordura CBS sem alterar de forma sensível os atributos físicos da manteiga de cacau
Abstract: Physical properties of pre-crystallized cocoa butter with the addition of alternative low and zero trans fats were studied. Binary mixtures of cocoa butter were conducted using cupuassu fat, CBR low trans and CBS at 5, 10, 15, 20, 25 and 30 % (w/w) levels. Pre-crystallization was carried out using a lab scale jacket vessel (700 mL) whit stirring system. Samples were evaluated by means of solid fat content, snap test, differential scanning calorimetry and X-Ray diffraction. The better condition for plain cocoa butter pre-crystallization was determined as follows: cooling rate (1,8 ºC/min), crystallization time (8 minutes), crystallization temperature (24 ºC). These conditions were also used for mixtures precrystallization (tempering). Mixtures with 20, 25 and 30 % of CBR and CBS were pre-crystallized at 23 ºC for 10 minutes. Regarding to solid fat content, cocoa butter fusion profile DS(25ºC-35ºC) was 59,2 %. Similar values were obtained for mixtures with up to 30 % of cupuassu and up to 30 % of CBR fats. Mixtures with CBS fat indicated eutectic effect. Snap value for crystallized cocoa butter was 2,48 kgf/cm2. The snap values decreased with the increase of the alternative fats proportion. Mixtures containing cupuassu fat or CBR have similar trend regarding to snap values profile. For mixtures with 30 % of cupuassu and CBR the snap values were 1,90 kgf/cm2 and 1,81 kgf/cm2, respectively. CBS 30% have the lowest snap value (0,39 kgf/cm2). Similar trend was observed regarding to melting point. Alternative fats incorporation decreased the melting point of the mixtures. Regarding to X-Ray diffraction, cocoa butter and cupuassu fat patterns results showed the formation of ß phase. For CBS and CBR patterns, there are evidence of ß¿ phase formation. The addition of 10 % CBR and CBS fat to cocoa butter was detected by X-ray diffraction patterns. The addition of up to 30 % cupuassu or CBR fat, and up to 10 % CBS butter showed no significant differences of physical properties when compared to cocoa butter
Doutorado
Engenharia de Processos
Doutor em Engenharia Química
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De, Wet Martie. "The effect of colonic propionate and the acetate : propionate ratio on risk markers for cardiovascular disease in westernised African men." Thesis, Bloemfontein : Central University of Technology, Free State, 2009. http://hdl.handle.net/11462/30.
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Soares, Fabiana Andreia Schafer de Martini. "Efeito da interesterificação química sobre as propriedades físico-químicas de misturas de estearina e oleína de palma." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/9/9133/tde-10032010-100042/.
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O desafio das indústrias de alimentos na substituição da gordura trans em diversos produtos reside no desenvolvimento de formulações e processos que apresentem funcionalidade equivalente e viabilidade econômica. A interesterificação química representa uma opção tecnológica importante para a produção de gorduras visando diversas aplicações comerciais, sem a formação de ácidos graxos trans. O óleo de palma contém quantidades aproximadamente iguais de ácidos graxos saturados e insaturados e pelo seu fracionamento obtêm-se duas frações: a estearina (fração sólida) e a oleína (fração líquida). A estearina e oleína de palma são opções interessantes para a produção de grande variedade de produtos como margarinas e shortenings. Assim, o objetivo deste trabalho foi modificar as propriedades físico-químicas de misturas de estearina e oleína de palma pelo uso da interesterificação química. As amostras foram analisadas quanto à composição em ácidos graxos e triacilgliceróis, distribuição regioespecífica dos ácidos graxos nos triacilgliceróis, índice de iodo, pontos de amolecimento e de fusão, conteúdo de gordura sólida, consistência e estrutura cristalina. Os ácidos graxos saturados são predominantes na estearina (71,9%), sendo que 65,5% correspondem ao ácido palmítico. A oleína tem como principal constituinte o ácido oléico, que representa 45,4%. À medida que aumenta a proporção de oleína de palma nas misturas, aumentam a quantidade de ácidos graxos insaturados e o índice de iodo e diminui a quantidade de ácidos graxos saturados. Após a interesterificação química, os pontos de fusão e amolecimento, a consistência e o conteúdo de gordura sólida aumentaram nas misturas que apresentavam maior proporção de oleína em função do aumento no teor de triacilgliceróis trissaturados. Por outro lado, estas propriedades não se modificaram nas misturas com maior proporção de estearina. Este comportamento se deve à distribuição aleatória dos ácidos graxos nos triacilgliceróis após a interesterificação, que forma triacilgliceróis em proporções diferentes das existentes originalmente. Os principais triacilgliceróis nas misturas foram PPP, PPO e POO. Antes da interesterificação os ácidos graxos saturados foram encontrados principalmente nas posições sn-1,3. Mudanças significativas na composição dos ácidos graxos na posição sn-2 após a interesterificação química foram encontradas em misturas com mais de 60% de oleína de palma. A mistura e a interesterificação permitiram obter gorduras com diferentes graus de plasticidade, aumentando as possibilidades de uso das frações estearina e oleína de palma.The challenge of the food industries for the replacement of trans fat in various products lies in the development of formulations and processes which have equivalent functionality and economic viability. The chemical interesterification of palm stearin and palm olein is an important technological option for the production of fats targeting commercial applications, without formation of trans fatty acids Palm oil contains similar amounts of saturated and unsaturated fatty acids. After fractionation two fractions are obtained: stearin (solid fraction) and olein (liquid fraction). Palm stearin and palm olein are alternatives for the production of many products, such as margarines and shortenings. The objective of this work was to modify the physical and chemical properties of mixtures of palm stearin and palm olein by using chemical interesterification. The following properties were analyzed: fatty acid and triacylglycerol compositions, regiospecific distribution of fatty acids in triacylglycerols, iodine value, softening and melting points, solid fat content, consistency and crystal microstructure. Saturated fatty acids are predominant in palm stearin (71.9%), which corresponds to 65.5% of palmitic acid. Palm olein has as its main constituent the oleic acid, which represents 45.4% of the unsaturated fatty acids. The increase of the proportion of palm olein in the mixture causes increase on the amount of unsaturated fatty acids and iodine value and decrease on the content of saturated fatty acids. After chemical interesterification, melting and softening points, consistency and solid fat content increased in the blends that had higher proportion of palm olein, as a consequence of the increase in the trisaturated triacylglycerols. On the other hand, these properties did not alter in the blends with higher proportion of palm stearin. This behavior is due to the random distribution of fatty acids in triacylglycerols after interesterification, which forms triacylglycerols in proportions that are different from those originally present. The major triacylglycerols in the blends were PPP, PPO and POO. Before interesterification the saturated fatty acids were found mainly in the sn-1,3 positions. Significant changes in the fatty acid composition in the sn-2 position after chemical interesterification were found in blends with more than 60 % of palm olein. Blending and interesterification of fats resulted in structured lipids with different degrees of plasticity, increasing the possibilities of use of stearin and olein fractions.
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Brekke, Sarah. "Trans-free fats and oils: chemistry and consumer acceptance." Kansas State University, 2013. http://hdl.handle.net/2097/16268.
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Master of ScienceDepartment of Food Science
Delores Chambers
Research has shown that trans fat consumption increases the levels of low-density lipoprotein (LDL) and has a direct correlation to the incidence of heart disease. It is now widely believed that trans fat intake adversely affects the health of consumers. A Food and Drug Administration (FDA) ruling, effective January 1, 2006, required declaration of trans fat content on all Nutrition Facts labels of food products. Around the same time local governments, such as the city of New York, and some restaurants followed suit by eliminating trans fats from their menus. The food industry’s initial concern with trans fat elimination/reduction was the loss of some functionality such as shelf life, stability, and creaming ability with trans-free fats and oils. Researchers are working to develop new trans-free fats and oils that do not have negative sensory properties and maintain the functionality of traditionally hydrogenated oils when used in baked and fried goods. This is an overview of the chemistry, health risks, and research that has been performed to either reduce or eliminate trans fats in food products.
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Xiao, Haiyi. "LOW TRANS FATTY ACID CONTAINING HYDROGENATED EDIBLE OILS." Miami University / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=miami1196130854.
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Lamb, Kelsey Ellen. "THE SURVIVAL OF VARIOUS PATHOGENIC ORGANISMS IN FATS AND OILS." UKnowledge, 2017. http://uknowledge.uky.edu/animalsci_etds/72.
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The research within this thesis sought to determine the ability of various animal derived fats and plant derived oils to support the survival of several pathogenic cocktails over a multitude of storage times. The Salmonella study explored the survival rate of a four strain Salmonella cocktail in beef tallow, pig lard, duck fat, coconut oil, and extra virgin olive oil over seven days at 26˚C and 37˚C storage. The animal fats and the coconut oil supported the survival of the bacteria until the conclusion of the study. The Shiga-toxin producing Escherichia coli study explored the survival rate of a five strain STECs cocktail in extra virgin olive oil over seven days at 26˚C and 37˚C storage. The two Listeria studies explored the survival rate of a four strain Listeria monocytogenes cocktail in extra virgin olive oil over several time periods with different frequencies of sample mixing. In vitro, all genuses showed a 2.5-log cfu/mL to ≥ 7-log cfu/mL reduction in the extra virgin olive oil by the conclusion of the experiments. Extra virgin olive oil was then applied to cooked pork tenderloin, cheddar cheese snack squares, and turkey lunchmeat in hopes of inhibiting the L. monocytogenes cocktail. No reduction was observed.
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Tu, Qingshi. "Fats, Oils and Greases to Biodiesel: Technology Development and Sustainability Assessment." University of Cincinnati / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1448037796.
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Jia, Huanfei. "Pretreatment of wastewater containing fats and oils using an immobilized enzyme." Thesis, Curtin University, 2002. http://hdl.handle.net/20.500.11937/448.
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This thesis investigates an application of immobilized lipase for pre-treating wastewater containing fats and oils, which is difficult to treat practically. The kinetics of soluble lipase was studied for establishing background of the lipase. The immobilization of lipase was adopted in order to repeatedly use the expensive lipase. The developed immobilization methods were based on the characteristics of carriers, but covalent bonding of lipase was preferred because of strong adsorption nature. Three types of materials, nylon membrane and polystyrene-divinylbenzene and silica gel beads, were used for studying the lipase immobilization characteristics. The lipase from Canada rugosa was chosen because of its relatively high catalytic activity and commercial availability. The oily wastewater sources used were a simulated mixture of olive oil and distilled water as well as actual restaurant oily wastewater. A packed bed reactor packed with immobilized lipase was suitable for the study. Moreover, a comparative study of anaerobic digestion of lipase treated and un-treated oily wastewater was undertaken to evaluate the efficiency of the lipase pre-treatment method due to lack of the relevant literature in the enzymatic wastewater treatment field. The kinetics of lipase catalyzed hydrolysis reactions was investigated in a stirred tank reactor. The experimental results confirmed that the lipase catalyzed reaction obeyed Michaelis-Menten model. The optimal pH and temperature of the lipase catalysed hydrolysis reaction were 7 and 37°C, respectively. The conversion of oil to fatty acid was dependent on the reaction time and mass of the enzyme used. The lipase activities depended on the concentrations of some selected additives. Calcium ion improved lipase activity significantly amongst the additives used.The immobilization of lipase was carried out using different materials, nylon membranes, polystyrene-divinylbenzene beads, and silica gel. Covalent adsorption was simple and successful for immobilizing the lipase onto nylon membrane which was pre-treated with HC1 solution for releasing amino groups. The adsorption of lipase was completed after only a 2-hour reaction time. It was much more practical for this shorter adsorption time (2 hours) rather than the 24 hours required for physical capillary adsorption of lipase. The properties of the immobilized lipase and the performance of the reactors we compared amongst the soluble and immobilized lipase forms. The immobilization, particularly for covalent bonding, made lipase more resistant to thermal deactivation. It was evident that the optimum temperature was shifted from 37°C for the soluble lipase to 45 and 40°C for immobilized lipase adsorbed onto nylon and polystyrene-divinylbenzene beads, respectively. The immobilized lipase could be used repeatedly with only little activity loss. The repeatedly operational stability made the reuse of the immobilized lipase possible. Comparison was also made between two types of beads, polystyrene-divinylbenzene beads and silica gels. Though polystyrene-divinylbenzene beads showed higher lipase activity and shorter adsorption time when compared to silica gels, the forme beads were not suggested for large scale study because of high cost of the beads. On improvement achieved in this work was that the 24 hours required for silanization of silica gel was reduced to only a few hours using evaporating 3-APTES in acetone instead of refluxing 3-APTES in toluene.It is worthwhile to point out that much higher enzyme activity was obtained using the packed bed reactor as against the membrane reactor when aqueous oil emulsion was fed into the reactors. The lipase activity was 64.2% of soluble lipase activity for the immobilized lipase in the packed reactor but its activity was hardly detectable in the membrane reactor. Moreover, the operation of the packed bed reactor solved the of separating problem that severely hampered the lipase catalytic activity in the membrane reactor in aqueous phase. This result suggests that the packed bed reacts with the immobilized lipase is applicable in treating oily wastewater. The intrinsic parameters, Vmax and Km, were evaluated to study the internal diffusional effects of the porous spherical silica gel on the immobilized lipase. The changes of Vmax and Km for the immobilized lipase from those of the soluble lipase indicated that some alteration in the lipase intrinsic properties was caused by the immobilization of lipase. However, the magnitude of Thiele modulus suggested the immobilized lipase was most likely reaction controlling. In addition, good agreement for Vmax and Km from experiments and numerical model estimations seemed to suggest that the numerical model could be used for estimating Vmax and Km for the immobilized lipase.An application was tried for conducting the hydrolysis of oily restaurant wastewater by soluble and the immobilized lipase. Enzyme activity of both forms was severely inhibited by the oily wastewater. The enzymatic activity was only 20% and 15% for soluble and the immobilized lipase, respectively, when compared to the initial activity value for the hydrolysis of olive oil by soluble lipase. Evaluation of the efficiency for the proposed lipase pre-treatment method was carried out by monitoring the performance of two anaerobic digesters. These two digesters were fed with lipase treated and untreated restaurant wastewater that was neutralised with KOH solution prior to feeding. The oil-floating problem was minimised by this saponification of fatty acids with potassium hydroxide. However, there was no clear sign of an improvement for the treatment efficiency of the anaerobic digesters in terms of COD removal and methane production rate resulted in digesting lipase treated oily wastewater when compared to the one without lipase pre-treatment.
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Jia, Huanfei. "Pretreatment of wastewater containing fats and oils using an immobilized enzyme." Curtin University of Technology, Department of Chemical Engineering, 2002. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=13326.
Full textAbstract:
This thesis investigates an application of immobilized lipase for pre-treating wastewater containing fats and oils, which is difficult to treat practically. The kinetics of soluble lipase was studied for establishing background of the lipase. The immobilization of lipase was adopted in order to repeatedly use the expensive lipase. The developed immobilization methods were based on the characteristics of carriers, but covalent bonding of lipase was preferred because of strong adsorption nature. Three types of materials, nylon membrane and polystyrene-divinylbenzene and silica gel beads, were used for studying the lipase immobilization characteristics. The lipase from Canada rugosa was chosen because of its relatively high catalytic activity and commercial availability. The oily wastewater sources used were a simulated mixture of olive oil and distilled water as well as actual restaurant oily wastewater. A packed bed reactor packed with immobilized lipase was suitable for the study. Moreover, a comparative study of anaerobic digestion of lipase treated and un-treated oily wastewater was undertaken to evaluate the efficiency of the lipase pre-treatment method due to lack of the relevant literature in the enzymatic wastewater treatment field. The kinetics of lipase catalyzed hydrolysis reactions was investigated in a stirred tank reactor. The experimental results confirmed that the lipase catalyzed reaction obeyed Michaelis-Menten model. The optimal pH and temperature of the lipase catalysed hydrolysis reaction were 7 and 37°C, respectively. The conversion of oil to fatty acid was dependent on the reaction time and mass of the enzyme used. The lipase activities depended on the concentrations of some selected additives. Calcium ion improved lipase activity significantly amongst the additives used.The immobilization of lipase was carried out using different materials, nylon membranes, polystyrene-divinylbenzene beads, and silica gel. Covalent adsorption was simple and successful for immobilizing the lipase onto nylon membrane which was pre-treated with HC1 solution for releasing amino groups. The adsorption of lipase was completed after only a 2-hour reaction time. It was much more practical for this shorter adsorption time (2 hours) rather than the 24 hours required for physical capillary adsorption of lipase. The properties of the immobilized lipase and the performance of the reactors we compared amongst the soluble and immobilized lipase forms. The immobilization, particularly for covalent bonding, made lipase more resistant to thermal deactivation. It was evident that the optimum temperature was shifted from 37°C for the soluble lipase to 45 and 40°C for immobilized lipase adsorbed onto nylon and polystyrene-divinylbenzene beads, respectively. The immobilized lipase could be used repeatedly with only little activity loss. The repeatedly operational stability made the reuse of the immobilized lipase possible. Comparison was also made between two types of beads, polystyrene-divinylbenzene beads and silica gels. Though polystyrene-divinylbenzene beads showed higher lipase activity and shorter adsorption time when compared to silica gels, the forme beads were not suggested for large scale study because of high cost of the beads. On improvement achieved in this work was that the 24 hours required for silanization of silica gel was reduced to only a few hours using evaporating 3-APTES in acetone instead of refluxing 3-APTES in toluene.
It is worthwhile to point out that much higher enzyme activity was obtained using the packed bed reactor as against the membrane reactor when aqueous oil emulsion was fed into the reactors. The lipase activity was 64.2% of soluble lipase activity for the immobilized lipase in the packed reactor but its activity was hardly detectable in the membrane reactor. Moreover, the operation of the packed bed reactor solved the of separating problem that severely hampered the lipase catalytic activity in the membrane reactor in aqueous phase. This result suggests that the packed bed reacts with the immobilized lipase is applicable in treating oily wastewater. The intrinsic parameters, Vmax and Km, were evaluated to study the internal diffusional effects of the porous spherical silica gel on the immobilized lipase. The changes of Vmax and Km for the immobilized lipase from those of the soluble lipase indicated that some alteration in the lipase intrinsic properties was caused by the immobilization of lipase. However, the magnitude of Thiele modulus suggested the immobilized lipase was most likely reaction controlling. In addition, good agreement for Vmax and Km from experiments and numerical model estimations seemed to suggest that the numerical model could be used for estimating Vmax and Km for the immobilized lipase.
An application was tried for conducting the hydrolysis of oily restaurant wastewater by soluble and the immobilized lipase. Enzyme activity of both forms was severely inhibited by the oily wastewater. The enzymatic activity was only 20% and 15% for soluble and the immobilized lipase, respectively, when compared to the initial activity value for the hydrolysis of olive oil by soluble lipase. Evaluation of the efficiency for the proposed lipase pre-treatment method was carried out by monitoring the performance of two anaerobic digesters. These two digesters were fed with lipase treated and untreated restaurant wastewater that was neutralised with KOH solution prior to feeding. The oil-floating problem was minimised by this saponification of fatty acids with potassium hydroxide. However, there was no clear sign of an improvement for the treatment efficiency of the anaerobic digesters in terms of COD removal and methane production rate resulted in digesting lipase treated oily wastewater when compared to the one without lipase pre-treatment.
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Palmer, Fiona M. "An investigation of the non volatile decomposition products in heated oils." Thesis, London South Bank University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.261041.
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Ziniades, Catherine. "The development of an industrial process to produce AC γ-linolenic acid using Choanephora cucurbitarum." Master's thesis, University of Cape Town, 1990. http://hdl.handle.net/11427/22047.
Full textAbstract:
Bibliography: pages 163-169.The objective of this work was to produce γ-linolenic acid (γLA) using a fungus in submerged fermentation. Selection work was aimed at identifying a fungal strain capable of yielding a high level of γLA in an industrial fermentation. Thirty-nine fungal strains were screened under shake flask conditions. The major criteria used in evaluating these strains were, the yield of γLA per unit volume (g/l) and γLA as a percentage of fatty acids, which is important in the downstream processing of γLA . Other parameters of industrial importance such as strain handling and the fatty acid profile were also considered. Eleven fungi in the order Phycomycetes were identified after initial screening. From these fungi, a strain of Choanephora cucurbitarum was found to give superior γLA yields. c. cucurbitarum produced γLA yields of 331mg/l and 674mg/l in shake flask and laboratory fermenters respectively. This strain had other industrially beneficial qualities such as good sporulation, a good biomass of 22, 5g/l and a relatively high yield of γLA of 2,99g/100g dry matter. Subsequently a Zygorhynchus heterogamus strain was found to give similar yields of γLA to c. cucurbitarum. z. heterogamus also had a high γLA : linoleic acid ratio which aids the purification of γLA . This is the first known report of a high level of γLA in the genus Zygorhynchus. The industrial development of γLA production by Zygorhynchus is not reported.
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Kalu, Clara U. U. "A chemical and organoleptic assessment of autoxidising oils." Thesis, Liverpool John Moores University, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262066.
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McGill, Jeremy Parker Firman Jeffre D. "Effect of high peroxide value fats on performance of broilers in normal and immune challenged states." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6471.
Full textAbstract:
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 18, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Jeffre D. Firman. Includes bibliographical references.
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Morlok, Kathleen M. "Food scientist's guide to fats and oils for margarine and spreads development." Manhattan, Kan. : Kansas State University, 2010. http://hdl.handle.net/2097/4205.
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Lambert, Marc S. "Hepatic metabolism of chylomicron remnants derived from different dietary oils and fats." Thesis, Royal Veterinary College (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.522619.
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Barton, Paul. "Enhancing separation of fats, oils and greases (FOGs) from catering establishment wastewater." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/8052.
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Removal of fats, oils and greases (FOG) from commercial food premises prior to discharge of wash waters into the sewer is critical in restricting blockage events. The FOG droplets that form are commonly removed in passive gravity separators. Enhanced separation through design modification, would allow a reduction in size required to achieve target removal. The aim of the project was to determine the feasibility of enhancing removal of FOGs in gravity separation devices and or in post treatment units. The thesis work examined the effect characteristics of oil droplet size and density had on FOG removal with a view to increasing droplet rise rates and hence separation. Examination of kitchen wastewater from a number of restaurants established that droplet sizes were typically in the mechanically emulsified oil size range, often with high zeta potential indicating electrostatic stabilisation of suspensions. Oil removal rates were examined using different oils typical of food preparations in laboratory scale experiments. Under a fixed energy input the different oils produced different droplet size distributions such that very different separation efficiencies were observed. The removal rates obtained allowed the prediction of oil removal from a sample in a given time when the median droplet size and density of the oil were known. For effective understanding of separator design and testing, droplet densities and sizes must be adequately measured and replicated. In addition, the light fuel oil used in the certification test produced very unstable suspensions, easily separable in the standard testing conditions, proving it a poor surrogate test material. Pre-formed droplets of sunflower oil were treated in a vertically aligned reaction chamber with an ultrasonic transducer fitted at the base. FOG removal, measured as HEM removal, was monitored as a function of power input, frequency, reactor size and residence time, the incoming flow entered counter currently to the ultrasonic wave propagation. The ultrasound treatment procedure removed 80% of oil from a suspension of droplets in the mechanically emulsified oil size range during the course of a 54 minute continuous experiment compared to 20-30% removal in the case of an equivalent separated without ultrasonic enhancement. The enhanced separation was found to be dependent on the power input and the reactor size. Application of ultrasound energy in modified grease separators to remove short-circuiting droplets would allow a reduction in overall size of units through reduced residence time requirement.
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Bailie, Pamela M. "An investigation into the hydrolysis of fats and oils using immobilised lipases." Thesis, Queen's University Belfast, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286852.
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Sadeghi-Jorabchi, Houtan. "The development of vibrational spectroscopy for the analysis of fats and oils." Thesis, University of East Anglia, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303016.
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Morlok, Kathleen M. "Food scientist’s guide to fats and oils for margarine and spreads development." Kansas State University, 2010. http://hdl.handle.net/2097/4205.
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Master of ScienceFood Science Institute - Animal Science & Industry
Kelly J. K. Getty
Fats and oils are an important topic in the margarine and spreads industry. The selection of these ingredients can be based on many factors including flavor, functionality, cost, and health aspects. In general, fat is an important component of a healthy diet. Fat or oil provides nine calories per gram of energy, transports essential vitamins, and is necessary in cellular structure. Major shifts in consumption of fats and oils through history have been driven by consumer demand. An example is the decline in animal fat consumption due to consumers’ concern over saturated fats. Also, consumers’ concern over the obesity epidemic and coronary heart disease has driven demand for new, lower calorie, nutrient-rich spreads products. Fats and oils can be separated into many different subgroups. “Fats” generally refer to lipids that are solid at room temperature while “oils” refer to those that are liquid. Fatty acids can be either saturated or unsaturated. If they are unsaturated, they can be either mono-, di-, or poly-unsaturated. Also, unsaturated bonds can be in the cis or trans conformation. A triglyceride, which is three fatty acids esterified to a glycerol backbone, can have any combination of saturated and unsaturated fatty acids. Triglycerides are the primary components of animal and vegetable fats and oils. The ratio of saturated to unsaturated fatty acids in these fats and oils has a great impact on their functionality. Common fats and oils include butterfat, beef tallow, fish oils, soybean oil, rapeseed (canola) oil, corn oil, cottonseed oil, olive oil, sunflower oil, palm oil, palm kernel oil, coconut oil, linseed (flax) oil, and safflower oil. Typical fat and oil modification techniques include hydrogenation, interesterification, alternative hydrogenation, fractionation, blending, farm/field practices and genetic modification, and the use of fat replacers. There are many processing techniques that can be utilized in margarine and spreads production. The process can be optimized for each margarine or spreads product. There are many fats and oils in margarine and spreads formulations. Familiarity with commonly used fats and oils in regards to availability, cost, nutrition, chemistry, and functionality are important when creating a cost-effective, functional margarine or spreads product.
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Lunnbäck, Johan. "Hydrodynamic cavitation applied to anaerobic degradation of fats, oils and greases (FOGs)." Thesis, Linköpings universitet, Tema Miljöförändring, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-140685.
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To increase profitability for biogas production, new innovative substrates and condition of operations needs to be implemented. At the current state, fats, oils and greases (FOGs) represent a promising substrate even though it brings operational challenges to the anaerobic digestion process. By utilizing hydrodynamic cavitation (HC) as a pre-treatment of the FOGs, the efficiency of FOGs’ co-digestion with wastewater sludge can be significantly improved. Preliminary experiments conducted on oil and water demonstrates that the HC pre-treatment improves the oil solubilisation as well as forms stable oil and water emulsion that last for several hours. The pre-treatment also improved the soluble chemical oxygen demand (COD) of biosludge (BiSl) by up to 115% and the initial degradation rate by up to 35%. In a semi-continues system, this allowed a significant increment in the specific methane yield depending on the organic loading rate (OLR) applied1. With sufficient process optimization, the HC-pre-treatment may prove to be an energy efficient and effective pre-treatment of FOGs.
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Stewart, David I. "The effect of low melting oils on the crystallisation of confectionery fats." Thesis, Loughborough University, 2017. https://dspace.lboro.ac.uk/2134/24420.
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This thesis concentrates on gaining a fundamental understanding of the crystallisation, phase behaviour, and melting in relatively simple fat/oil blends. This is the first reported study of hot stage microscopy (HSM) experiments on tripalmitin (PPP)/triolein (OOO), 1,3-dipalmitoyl-2-oleoylglycerol (POP)/OOO, and cocoa butter (CB)/hazelnut oil (HZ) systems. The HSM technique allows the visualisation of the initial crystallisation, polymorphic transformations, and melting of fat crystals; melting points can also help identify polymorphic form. Supporting experiments were also performed using differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), and X-ray diffraction (XRD). In PPP-OOO samples, HSM visualised for the first time a melt-mediated transformation from β' to β across a small liquid gap between the untransformed (β') and transformed (β) material. This behaviour was not seen with pure PPP. Melting points obtained by HSM for the PPP/OOO system were above those predicted by the Hildebrand equation, but this is attributed to the non-equilibration of concentration gradients within the system. This was evidenced by the fact that a rapid cooling rate (to produce a finer microstructure with smaller crystals, and hence reduce diffusion distances) combined with a slower remelt rate enabled samples to melt close to ideal. Indeed, final melting points obtained via HSM were consistently higher than DSC results across all systems; convection and the more three-dimensional system in DSC (as compared with the two-dimensional HSM system) may have aided melting. The POP/OOO system displayed complex remelting behaviour, especially when warmed at a relatively slow rate; this also resulted in a higher production of β. Liquid oil content was shown to not only be important in aiding transformation of lower forms to β, but also reduced the number of polymorphs observed upon remelting, as compared with pure fat samples. Liquid oil content was also shown to be crucial for transformation to β in the CB/HZ experiments; very few β crystals were seen in pure CB samples. Experiments carried out on DSC for both CB and CB-HZ cooling at 1°C/min or faster produced both α and β' crystals, but for CB-HZ this also then led to some transformation from α to β. The β polymorph was not observed when only β' was formed at slower cooling rates. A curious result was that the effect was stronger the longer the samples were held at 0°C before rewarming, with the α becoming more resilient against transforming to β' and instead transforming directly to β. More extensive transformation to β occurred if the sample was held for 30 min at 18°C or 22°C during the rewarming step. As well as showing differences in melting temperatures, the HSM and DSC results also did not always match with respect to polymorphic form. Small quantities of β crystals were seen in HSM samples that were not always seen in thermograms of equivalent DSC samples. This either highlights the limitations of DSC or suggests that polymorphic behaviour in the more fluid DSC system differs to that in HSM, or both. Growth rate analysis of PPP (in OOO) showed that both reduced supersaturation and supercooling can be correlated with the growth rates of β' and β. Growth rates of β that occurred via the melting of β' were well correlated with driving forces that took into account that the concentration of PPP in the liquid gap between β' and β (from which the β crystal was growing) was limited by the solubility of β' at the sample temperature. Whilst temperature is often seen as a key driver in governing polymorphic transformation, part of the temperature effect may be an indirect effect via the extra amount of liquid content at higher temperatures. The ability of oil to aid transformation to β may be relevant to food systems where this higher polymorphic form is the preferred type, such as chocolate. Potential applications could include producing novel fat blends with relatively stable fat network structures at a lower overall saturate level, or developing blends with bloom inhibiting properties.
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Parry, John Wynne. "Value-adding factors in cold-pressed edible seed oils and flours." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/4173.
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Thesis (Ph. D.) -- University of Maryland, College Park, 2006.Thesis research directed by: Food Science. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Halfani, M. R. "Investigation of process flowsheets for manufacture of edible oils from seeds." Thesis, University of Leeds, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.233907.
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Chan, Yip-wai Edward. "A preliminary study on cooking oil waste management in Hong Kong /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2012613X.
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He, Hanping, and 何漢平. "Oil and squalene in Amaranthus." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B31244191.
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