Literatura académica sobre el tema "Cheese"

Purpose The purpose of this study was to establish the degree of ripening of natural goat cheese used as a raw material; to formulate a spreadable processed cheese with creamy consistency; and to determine the level of each process variable. Design/methodology/approach Cheeses of various ripening times were selected for the formulation through cluster analysis. The effect of the final moisture was studied using the same proportion of fresh and ripened cheeses in the formulation, and three melting temperatures were tested. Findings Goat cheeses ripened for 10, 20 and 40 days were chosen for the formulation of spreadable processed cheese. Final moisture content of 63.0 ± 0.1 per cent was selected (p = 0.0008). Melting temperature at 85.0 ± 0.1°C for 9.0 ± 0.5 min was suitable to homogenize the cheese mass (p = 0.001). The level of variables was validated by changing the proportions of natural goat cheeses selected. Four formulations were obtained with a consistency similar to that of the commercial reference. Practical implications Processed cheese is produced by blending shredded natural cheeses of different types and degrees of ripening. The use of ripening goat cheeses as a raw material in processed cheeses contributes to the added value of the local goat milk chain. Goat cheeses have an acid and slightly salty taste and medium to long persistence. Originality/value The results of this work can be used by processed cheese manufacturers to better understand the impact of goat cheese ripening on processed cheese quality. The industry can also use these results to introduce the product onto the market and plan their marketing campaign.

The purpose of the present study was to evaluate the antioxidant, anti-inflammatory activity and peptide levels of Feta cheese and other brined cheeses, and Metsovone cheese and other smoked cheeses. Feta, goat and cow cheeses are classified as brined. Feta cheese is made exclusively from ewe milk or ewe milk with the addition of a small amount of goat milk. Metsovone and other smoked cheeses are made from cow milk with a possible addition of small amounts of ewe and goat milk. The antioxidant activity was determined using Folin and FRAP assays, while the peptide content was determined using Bradford and Lowry assays. The anti-inflammatory activity was assessed using the lipoxygenase inhibition assay. The assays were applied in the water-soluble extract of cheeses. The results showed that Feta cheese and brined cow cheese differed in antioxidant activity. Feta cheese and brined goat cheese also differed in both antioxidant activity and peptide levels. Specifically, Feta cheese had higher antioxidant activity in comparison with both goat and cow cheeses. As for peptide content, Feta cheese had a higher peptide level compared to goat cheese. The results also showed that Metsovone cheese and other smoked cheeses exhibited significant antioxidant activity and peptide levels. Moreover, the water-soluble extracts of all cheeses showed some anti-inflammatory activity.

Earlier work by others indicated that a mold colony grows radially at a constant rate on solid media. This concept was used in our study to develop a method for quantifying growth of mold on cheese. The ability of molds to grow on cheeses or pasteurized process cheese made with or without addition of sorbate was compared. Cheeses tested were mild Cheddar, aged Cheddar, aged-smoked Cheddar, brick and pasteurized process cheese. Pasteurized process cheeses were made from the natural cheeses by addition of water and a phosphate salt, then the mixture was heated. Some pasteurized process cheese from mild Cheddar was made to contain 0–500 ppm sorbic acid. Natural cheeses were sliced under aseptic conditions and were placed in sterile petri-plates. The hot and molten pasteurized process cheeses were poured into petri-plates. A spore suspension of Aspergillus parasiticus or Penicillium camemberti was inoculated onto the center of the cheese slice or pasteurized process cheese, and plates were covered and incubated at 22°C. The radius of mold colonies was measured at 24-h intervals. Data were analyzed by linear regression and lag period and rate of radial growth were calculated. Mold colonies grew radially at constant rates on cheeses and pasteurized process cheese. Lag in growth of each mold was longest on aged Cheddar cheese and pasteurized process cheese made from it, whereas it was shortest on mild Cheddar, brick and pasteurized process cheeses made therefrom. A. parasiticus grew faster on all cheeses and pasteurized process cheeses than did P. camemberti. Aged Cheddar cheese and pasteurized process cheese made from it effectively slowed the growth of both molds that were studied. Pasteurized process cheese containing sorbic acid inhibited growth of both molds. Generally, the higher the concentration of sorbic acid in the pasteurized process cheese, the slower was mold growth and the longer was the lag period.

Sudanese White cheese (Gibna Bayda) was produced by using different starter culture combinations to find the most suitable starter culture. Four cheeses were prepared with pasteurized milk inoculated with different starter culture combinations at the rate of 1% (v/v), while control cheese (T5) was made without the addition of starter culture. Cheeses were stored in vacuum bags at 4 °C and 15 °C for 90 days, and the properties of cheeses were determined at intervals of 1, 15, 30, 45, 60, and 90 days. The yield of control (T5) cheese was higher than T4 and T1 cheeses and lower than T2 and T3 cheeses. Total solids, protein, fat, and acidity values and lipolysis degree of control (T5) cheese were lower than T4 and T1 cheeses, and higher than T2 and T3 cheeses. The proteolysis degree of control (T5) cheese was the lowest when the cheeses were stored at 15 °C, and the highest among all cheeses except T1 and T4 cheeses when stored at 4 °C. The acidity value, protein, salt, and the degree of lipolysis and proteolysis were higher in cheese samples stored at 15 °C. All sensory properties scored best in T1, T4, and T3 cheeses compared to control (T5) cheese. Cheeses stored at 4 °C scored better for odor and overall acceptability. The use of starter culture in the production of white cheese positively affected the properties of the cheeses, especially T4 cheeses containing Lactobacillus helveticus, and T1 cheeses made with mesophilic culture were better than other cheeses in terms of physicochemical and sensory properties.

In this paper, influence of the composition of autohtonous Sjenica cheese and composition of cheese made from cow milk in the type of Sjenica cheese were comparatively investigated. Autohtonous Sjenica cheese, made from ewe's milk and Sjenica type cheese made from cow's milk both had high content of moisture (53.46% and 59.56% respectively), which is the result of production process (coagulation time, curd processing, drying and salting). According to moisture content in fat free basis - MFFB (73.51% and 73.38% respectively) both cheeses belong to soft cheeses group, and according to fat in total solids - FTS (58.66% and 46.75% respectively) they belong to a group of whole milk cheeses. Ripening coefficient of Sjenica cheese made from ewe's milk (21.42%) was larger than ripening coefficient of Sjenica type cheese made from cow's milk (20.41%). Big differences in chemical composition of both cheeses are due to non-uniformly technology, which imposes need to assimilate technology process of Sjenica cheese production and fulfill geographic origin protection of Sjenica cheese as autohthonous cheese characteristic for wider area of Sjenicko-pesterska plateau.

The cysteine proteinase from Micrococcus sp. INIA 528 was added at three concentrations to pasteurized cows' milk to study its effect on the ripening process of Hispanico cheese. Dry matter was higher in whey from experimental cheeses than in whey from control cheese manufactured from milk with no added proteinase. No differences in cheese proteolysis were found 24 h after manufacture. Residual αs- and β-caseins were significantly lower, and N soluble at pH 4·6 and in trichloroacetic acid significantly higher, in experimental cheeses than in control cheese from day 15. Hydrophobic and hydrophilic peptides in the water-soluble fraction of cheese measured by absorption at 280 nm were significantly higher in experimental cheeses than in control cheese from days 1 and 15 respectively. Texture was less firm in experimental than control cheese from day 30. Bitterness, detected in cheese with the highest levels of added cysteine proteinase, adversely affected cheese flavour. Flavour intensity was significantly higher from day 30 in cheeses with added proteinase than in control cheese.

Abstract Modern man cannot imagine his diet without milk and dairy products, above all cheese. Uzbekistan has traditionally provided dairy products, including cheese, not only for itself but also for other neighbouring countries. Cheese has a long history and this naturally fermented dairy product contains a range of distinctive flavors. Microorganisms in variety cheeses are an essential component and play important roles during both cheese production and ripening. However, cheeses from different countries are still handmade, the processing technology is diverse, the microbial community structure is complex and the cheese flavor fluctuates greatly. Therefore, studying the general processing technology and relationship between microbial structure and flavor formation in cheese is the key to solving the unstable quality and standardized production of cheese flavor on basis of maintaining the flavor of cheese. Cheese processing, including cheese-making, cheese preparation and the different stages of cheese-making. Much attention is given to bacterial starters, bacteriophages, milk-forming enzymes used in cheese-making, and the production of new cheese varieties, including those in Uzbekistan. This paper reviews the research progress on the general processing moulding, pressing and salting points of natural cheese, the biochemical pathways for production of flavor compounds in cheeses, the diversity and the role of yeasts in cheese.

ABSTRACTShiga toxin-producingEscherichia coli(STEC) is an important cause of food-borne illness. The public health implication of the presence of STEC in dairy products remains unclear. Knowledge of STEC behavior in cheeses would help to evaluate the human health risk. The aim of our study was to observe the growth and survival of experimentally inoculated STEC strains in raw-milk cheeses manufactured and ripened according to five technological schemes: blue-type cheese, uncooked pressed cheese with long ripening and with short ripening steps, cooked cheese, and lactic cheese. Cheeses were contaminated with different STEC serotypes (O157:H7, O26:H11, O103:H2, and O145:H28) at the milk preparation stage. STEC growth and survival were monitored on selective media during the entire manufacturing process. STEC grew (2 to 3 log10CFU · g−1) in blue-type cheese and the two uncooked pressed cheeses during the first 24 h of cheese making. Then, STEC levels progressively decreased in cheeses that were ripened for more than 6 months. In cooked cheese and in lactic cheese with a long acidic coagulation step (pH < 4.5), STEC did not grow. Their levels decreased after the cooking step in the cooked cheese and after the coagulation step in the lactic cheese, but STEC was still detectable at the end of ripening and storage. A serotype effect was found: in all cheeses studied, serotype O157:H7 grew less strongly and was less persistent than the others serotypes. This study improves knowledge of the behavior of different STEC serotypes in various raw-milk cheeses.

Yeast extract was used as a nutrient for growing lactobacilli in reduced-fat Cheddar cheese as early growth of non-starter lactic acid bacteria (NSLAB) in Cheddar cheese is suppressed by pasteurization of milk and the hostile environment of the cheese. Reduced-fat Cheddar cheese was manufactured from 100 kg standardized milk on two occasions. After milling, the curd was divided into two portions, C and E. To control portion, C, salt was added at normal levels. A mixture of salt and yeast extract was added to the experimental, E. The cheeses were ripened for 7 months at 8 °C and assessed for proteolysis and NSLAB growth during ripening. Mean % moisture, fat, protein, salt and pH were 40·6, 20·5, 31·1, 1·72 and 5·22 respectively, in E cheeses, and 39·5, 20·5, 30·9, 1·68 and 5·22, respectively, in C cheese. NSLAB counts in E cheeses were 101, 103, 105 cfu/g compared with 0, 101, 104 cfu/g in C respectively, after 1, 7 and 30 d of ripening. After 60 d, cell densities of NSLAB were similar (∼106 cfu/g) in C and E cheese. Addition of yeast extract to curd affected neither the electrophoretic patterns of cheese nor its water-soluble N content during ripening. However, the total free amino acids were significantly higher in E cheese than C cheese throughout ripening, suggesting faster secondary proteolysis in the former cheeses. A 6-member trained descriptive panel evaluated the cheese at 7 months and found that the E cheeses had higher intensities of whey, fruity, sulphur, nutty, sweet and sour flavours, but had lower intensities of brothy flavours as compared to C cheeses. Also, the E cheeses were perceived to be more mature than corresponding C cheese. Results show that addition of yeast extract to cheese curd is a promising method of enhancing flavour development in ripened cheeses.

Kashkaval of Pindos cheese was successfully produced using 100% sheep milk (KS) or with the addition of 10% goat milk (KG). Urda cheese was manufactured using 100% sheep (US) or 90% sheep–10% goat (UG) whey from the production of kashkaval of Pindos cheese. Both cheeses were made taking into account their traditional cheese-making methods. The cheeses were assessed for their chemical, microbiological and organoleptic characteristics. Generally, no significant differences were observed between KS and KG cheese and between US and UG cheese regarding their physicochemical, textural characteristics, soluble nitrogen fraction and total fatty acid content. The fat content of Urda cheese was low, in accordance with the demand of consumers for healthy products. KS cheeses showed higher total volatile compounds than KG cheeses at 60 and 90 days of ripening and storage as well as lower counts of thermophilic–mesophilic lactic acid bacteria. No differences were observed in the microbial counts between US and UG cheeses. Acetone, hexanal, 2 heptanone, ethanol and toluene were found in abundance in Urda cheeses. Both kashkaval of Pindos and Urda cheeses received high scores during the organoleptic evaluation. The obtained data may lead to the production of both cheeses with standard characteristics according to the traditional recipes and improve their recognition.

The cheese making process at Anchor Products Hautapu was having difficulty reaching the now outdated New Zealand Dairy Board uniformity targets. Even though there is no longer a direct financial benefit in reaching these targets consistently, there is the benefit of being able to show the customer that the product which they are receiving is as consistent as possible. This project was carried out by systematically investigating each section of the cheese making process, looking for variations that were likely to affect the final product. Where variations were found methods for eliminating them or minimising their effect on the final product were developed. The largest source of variation was found to be caused by fluctuations in the curd depths on the belts of the Alf-O-Matic cheddaring machine. Overlapping the ends of consecutive cheese making tanks as well as the re-calculations of the pump out flow rates have been proposed to remedy this problem. Where the curd is drawn off from the end of the Alf-O-Matic cheddaring machine was also found to be causing variation in the product due to particle stratification affecting the salt levels of blocks that were being produced. Recommendations for methods to reduce the level of stratification have been suggested including using a capacitance probe to control the curd level. Further variations were occurring within the cheese making tanks with cutting and stirring speeds differing from tank to tank. The tanks were also being flushed with cold water causing moisture spikes in the product. Both of these problems have been eliminated by changes to the PLC program. Small improvements have been seen in the process with the changes that have already been carried out. Large improvements are expected if the rest of the recommendations are implemented. The largest improvements should be seen with the realisation of an overlapped pump out system.

Tableau d'honneur de la Faculté des études supérieures et postdoctorales, 2016-2017
Le fromage Mozzarella entre dans la composition de plusieurs mets populaires d’Amérique du Nord. L’aptitude de ce fromage à être râpé et ses propriétés caractéristiques de cuisson en font un ingrédient idéal. Ces qualités sont attribuées principalement aux propriétés physiques particulières de ce fromage sous certaines conditions de cisaillement et de température. Le but de ce projet était d’évaluer l’impact de différentes stratégies couramment mises en oeuvre dans l’industrie fromagère sur la composition, la microstructure et les propriétés physiques du fromage. Diverses stratégies ont été étudiées : les conditions de filage du caillé lors du procédé de « pasta filata », l’addition de protéines sériques dénaturées, le contrôle de la minéralisation et le vieillissement du fromage. Les résultats ont démontré que le contrôle de l’intensité mécanique et thermique fournie lors du filage permettait respectivement de réduire les pertes de solides et d’améliorer la répartition de la phase aqueuse dans la matrice fromagère. L’aptitude au râpage du fromage peut être optimisée en combinant l’utilisation de plusieurs stratégies dont la réduction du calcium colloïdal, un temps de vieillissement adéquat et un râpage à basse température. Par ailleurs, des changements aux facteurs mentionnés précédemment sont apportés lors de l’ajout de protéines sériques dénaturées, ces dernières ayant un impact sur la composition et la structure du fromage. Des modèles prédictifs de l’aptitude au râpage ont été développés en sélectionnant uniquement les descripteurs de composition et de texture pertinents. La perception sensorielle du fromage cuit sur pizza et les propriétés physiques du fromage fondu ont été considérablement influencées par l'évolution physico-chimique du fromage au cours du vieillissement. L’utilisation d’une nouvelle approche pour la caractérisation des propriétés rhéologiques du fromage fondu sous fortes contraintes a permis d’établir de bonnes relations avec les descripteurs sensoriels de texture. Ce travail a permis de valider l’hypothèse que l’utilisation d’une ou plusieurs stratégies simples et accessibles pouvait être mise de l’avant afin d’optimiser les propriétés physiques du fromage Mozzarella. Cela contribue à une meilleure compréhension des facteurs pouvant être contrôlés afin de développer des fromages avec des attributs spécifiques, lorsqu’utilisés comme ingrédient.
Mozzarella cheese is expected to perform various key attributes when used as a food ingredient. The shreddability and the melting properties of cheese during and after baking are mainly governed by the physical properties of cheese when subjected to external factors such as shear and temperature. Therefore, the goal of this project was to evaluate the impact of cheese-making strategies commonly used in the dairy processing industry on the cheese composition, microstructure, and physical properties. Various strategies were studied: pasta filata process conditions, addition of denatured whey protein (WP-D) to milk, control of curd mineralization, and cheese aging. Results showed that controlling the mechanical and thermal intensity during the pasta filata process can lead to reduced cheese solid losses and a better distribution of water within cheese microstructure, respectively. The ability of cheese to be shredded can be increased using a combination of multiple factors such as lowering colloidal calcium phosphate associated with casein, proper aging, and by reducing cheese temperature before shredding. However, an optimisation of the previous factors should be done if WP-D is added because of its impact on cheese composition and structure. Predictive models to assess cheese shreddability were built using only few relevant compositional and textural descriptors. Sensory perception of baked cheese texture and physical properties of melted cheese were dramatically influenced by the physico-chemical evolution of cheese during aging. Melted cheese texture was satisfactorily related to different sensory attributes using a novel approach to determine the rheological properties under the large stress experienced during mastication. This work validated the hypothesis that simple cheese-making strategies, alone or combined, can be used to optimize the cheese physical properties. This contributes to a better understanding of the factors that can be controlled to improve or develop cheese ingredient with specific attributes.

The effect of reducing the fat content of low-moisture part-skim Mozzarella cheese from 19% to less than 5% on melted cheese properties, i.e., apparent viscosity, cheese melt, and cook color, was investigated. Functional properties of melt and stretch and cook color were evaluated at d 1, 7, 14, and 28. A rapid microwave oven method underestimated the moisture content of the low fat cheeses by approximately 10%. Low fat cheese did not melt as well as did the low-moisture part-skim Mozzarella cheese although the moisture content of the low fat cheese (moisture content ranged from 62.5% to 63.6%) was greater than the moisture content of the part-skim control (52.1 %). Storage for 28 d only marginally increased the meltability of low fat cheese. Lower fat content increased cook color. The amount of intact a αs-CN decreased by at least 48% in all cheeses as a result of proteolysis during 28 d of storage. The relative proportion of bound, entrapped, and expressible water was determined for a reduced-fat (8% fat) and control (19% fat) Mozzarella cheese on d 1, 7, 14, and 21 of refrigerated storage. Changes in the state of water were related to changes in cheese microstructure of a commercial Mozzarella cheese and to changes in cheese meltability of the control cheese. The amount of expressible water was proportional to fat content. Throughout storage, fat/serum channels became smaller and the protein matrix expanded into the areas between fat globules. The meltability of both cheeses increased during storage. Both cheeses contained 0.71g bound water/ g protein. Expressible water decreased in both cheeses until by d 21 no water was expressible. Entrapped moisture increased from approximately 10% to 60% for the control cheese and from approximately 33% to 50% for the reduced-fat cheese. An objective test was developed for measuring stretch, a characteristic of melted cheese. Three nonfat and four low-moisture part-skim cheeses were evaluated using the new test and the results compared with conventional test methods. Two new melted cheese parameters were defined: melt strength, the maximum load (g) obtained during the test, and stretch quality, the average load (g) as the cheese fibers stretched and elongated. Melt strength correlated with apparent viscosity. Stretch quality was determined for selected nonfat and low-moisture part-skim cheeses. A three-pronged probe was used to pull cheese vertically from a melted cheese pool. Use of this elongation stretch test, along with more traditional melted cheese tests, provides more complete information about the functional properties of Mozzarella cheese.

The use of slower acid-producing starter bacteria for the production of lower fat Cheddar cheese has lead to milder flavor Cheddar cheeses that lack intense Cheddar notes. The metabolism of methionine leads to the production of methanethiol, which is one of the desirable Cheddar cheese flavor compounds. The influence of NaCl and reduced pH was determined for aminopeptidase, lipase/ esterase, and methanethiol-producing capability in selected lactic acid bacteria and brevibacteria in simulated cheese-like conditions. The activity of each enzyme decreased with NaCl addition and pH reduction to approximate a Cheddar cheese environment (5% NaCl and pH 5.2). The mechanism for methanethiol production by the starter and adjunct bacteria was also investigated. Different enzyme systems were found to be responsible for methanethiol production in starter lactococci, lactobacilli, and brevibacteria. In the lactococci, enzymes that acted primarily on cystathionine were responsible for methanethiol production from methionine. Lactobacilli also contained cystathionine-degrading enzymes, but these enzymes have properties different from the lactococcal enzymes. Brevibacterium linensBL2 lacked cystathionine-degrading enzymes, but was capable of the direct conversion of methionine to methanethiol. L-Methionine γ-lyase from B. linens BL2 was purified to homogeneity, and was found to catalyze the α, γ elimination of methionine resulting in the production of methanethiol, α-ketobutyrate, and ammonia. Characterization of the pure enzyme demonstrated that it is pyridoxal phosphate dependent, which is active at salt and pH conditions existing in ripening Cheddar cheese. The addition of either B. linens BL2 or L-methionine γ-lyase to aseptic cheese curd slurries increased methanethiol and total volatile sulfur compound production. In an attempt to increase methanethiol production and Cheddar cheese flavor in reduced-fat Cheddar cheese, B. linens BL2 was added as a starter adjunct to 60% reduced-fat cheese. Sensory evaluation of the cheese indicated that B. linens BL2 improved the flavor of 60% reduced-fat Cheddar cheese. This suggests that the addition of B. linens BL2 is an alternative to the addition of lactic acid bacteria to improve Cheddar cheese flavor via the metabolism of methionine.

Various techniques for accelerating mature flavour development in Cheddar cheese were compared. Control cheese ( c) was manufactured by using Streptococcus cremor is AM2, a starter used in normal commercial manufacture. A combination of S. cremoris AM2 and Streptococcus lactis C2 Lac- Prt- mutant was used in the manufacture of test cheeses (M). §._. lactis C2 mutant was grown in glucose broth at 30°c and pH 6 .O for 16 hours, followed by concentration and diafiltration to 1011cfu mL - 1 using microfiltration equipment. The control cheesemilk was inoculated to 6x107 streptococci pe mL with S. cremoris AM2 and the mutant vat cheesemilk to 2x109 per mL with a combination of ~ cremoris AM2 and ~ lactis C2 mutant. The starter population in cheese containing mutant starter was 100 times that in control cheese (1010 compared to 10a). Cheeses were also made with added bacterial neutral proteinase (Neutrase, N) and stored at a0c (a) and 15°c ( 15) for 32 weeks. This resulted in cheese being subjected to the following treatments: ca (control), C15, CNa, CN15, Ma·, M15, MNa, and MN15. Cheddaring times were slightly reduced and milling acidities slightly higher in the vat . containing mutant starter. However the composition of all cheese was satisfactory. Bacteriological counts, proteolysis, rheological properties and flavour development of these cheeses were monitored at regular intervals throughout maturation. The order of the effectiveness of the treatment in accelerating ripening was MN15, >M15,> CN15,> C15,> MNa,> Ma,> CNa,> ca. Cheeses from these treatments attained the characteristics of control cheese stored at a0 c (Ca) for 6 months after 1.4, 1.7, 2.0, 2.6, 2.8, 3.2, 4.3 and 6.0 months respectively. Cheese quality was not adversely affected except for bitterness in CN8 cheese and overmaturity in CN15 cheese late in the storage period. The possible mechanisms and relative merits of the various treatments are discussed with special reference to an "active role" theory of starter bacteria in flavour development.

El objetivo general del presente TAF es el estudio del lanzamiento de un nuevo producto de fast food en el centro comercial Jockey Plaza, el mismo que se ofrece como un snack salado hecho de una masa crocante rellena con queso mozarella (ingrediente preponderante) y un ingrediente adicional Se plantean como objetivos específicos, analizar el entorno competitivo de empresas que comercializan productos similares o sustitutos con el fin de plantear estrategias de participación de mercado

The aim of this PhD thesis was the study of the genomic, biological and phenotypic background of bovine cheese-related traits. The primary goal of this PhD thesis was to unravel the genomic background of bovine milk technological and cheese-related traits to specific chromosomic regions (CHAPTERS 1 to 3). To achieve this, the cow’s ability to produce cheese was decomposed into 11 milk coagulation (MCP) and curd-firming properties (CFt), and 7 cheese yield and milk component recoveries into the curd (REC) traits. Besides, to tackle the problem of the large number of variables required to describe the cow’s ability to produce cheese, posing restrictions in the construction of selection indices, and thereby selection decisions, factor analysis (FA) was used (CHAPTERS 4 and 5). The MCP traits were: 3 traditional single point lacto-dynamographic properties (RCT: rennet coagulation time, min; k20: time to a curd firmness (CF) of 20 mm, min; a30: CF 30 min after rennet addition), 6 parameters modeling 360 CF data for each milk sample (CFP: potential asymptotic CF at infinite time, mm; kCF: curd firming instant rate constant, %×min-1; kSR: syneresis instant rate constant, %×min-1; RCTeq: RCT from modeling; CFmax: maximum CF, mm; tmax: time at CFmax, min), milk- protein (%) and pH. The 3 CY traits were the weight (wt) of fresh curd (%CYCURD), curd solids (%CYSOLIDS), and curd moisture (%CYWATER) as % of wt of milk processed. The 4 REC (RECFAT, RECPROTEIN, RECSOLIDS, and RECENERGY) were calculated as the % ratio between the nutrient in curd and the corresponding nutrient in processed milk. For FA 26 traits related to milk yield and quality (including milk protein fractions), MCP-CFt and CY-REC traits were analyzed. Single marker genome-wide association analyses (GWAS) complemented by gene-set enrichment and pathway-based analyses were conducted. In total, 1,152 Italian Brown Swiss cows reared in 85 herds were genotyped with the Illumina SNP50 Beadchip v.2. Single marker regression GWAS were fitted using the GenABEL R package (GRAMMAR-GC). The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway databases were queried for the enrichment analyses. In GWAS (CHAPTERS 1 and 2), sharp peaks were detected on Bos taurus autosome (BTA) 6, at 84 to 88 Mbp, with the highest peak detected at 87.4 Mbp in the region harboring the casein genes and more precisely of κ-CN (CSN3). Marker Hapmap52348-rs29024684 (~87.4 Mbp), closely located to the casein genes on BTA6, was strongly associated with RECFAT (P = 1.91×10-15) and CFP (P = 1.62×10-17). Evidence of quantitative trait loci at 82.6 and 88.4 Mbp on the same chromosome was found. On BTA11, marker ARS-BFGL-NGS-104610 (~104.3 Mbp) was highly associated with RECPROTEIN (P = 6.07×10-36). Apart from BTA6 and 11, SNP located in 15 more chromosomes (1, 2, 9, 12, 13, 14, 15, 16, 18, 19, 20, 23, 26, 27 and 28) were significantly associated to the MCP-CFt and CY-REC traits. The gene-set enrichment and pathway-based analysis (CHAPTER 3) revealed 21 GO and 17 KEGG categories significantly associated (false discovery rate controlled at 5%) with 7 of the traits (RCT, RCTeq, kCF, %CYSOLIDS, RECFAT, RECSOLIDS and RECENERGY), with some being in common between traits. The significantly enriched categories included calcium signaling pathway, salivary secretion, metabolic pathways, carbohydrate digestion and absorption, the tight junction and the phosphatidylinositol pathways, as well as pathways related to the bovine mammary gland health status, and contained a total of 150 genes located in all chromosomes but 9, 20, and 27. In FA (CHAPTERS 4 and 5), ten mutual orthogonal Fs were obtained using a varimax rotation. The 10 Fs explaining 74% of the original variability. Those Fs captured basic concepts of the “milk to cheese” process. More precisely, the first four Fs, sorted by variance explained, were able to capture the underlying structure of the CY percentage (F1%CY), the CF process with time (F2CFt), the milk and solids yield (F3Yield) and the presence of nitrogen (N) into the cheese (F4Cheese N). Moreover, 4 Fs (F5 αs1-β-CN, F7β-κ-CN, F8αs2-CN, F9αs1-CN-P) were related to the basic milk caseins (as1-CN, as2-CN, β-CN, κ-CN, and the phosphorylated form of as1-CN) and 1 factor was associated with the α-LA whey protein (F10α-LA). A factor describing the udder health status of a cow (F6Udder health), mainly loaded on lactose, other nitrogen compounds and SCS, was also obtained. In general, FA results were coherent to the given name of the factor. Stage of lactation had a significant effect for the majority of the Fs, followed by parity. Moreover, considerable genetic correlations existed among the Fs (CHAPTER 4). All Fs showed significant associations (P < 5 ×10-5) in GWAS, but F5Yield. High peaks on BTA6 (~87Mbp) and at the tail of BTA11 (~104Mbp) were mainly associated to F6β-κ-CN and F1Cheese N, respectively. In addition, 33 GO terms and 6 KEGG categories were mainly enriched for F8αs2-CN, but also for F1%CY, F4Cheese N, and F10α-LA. Biological pathways were mainly related to the broader categories of ion activity, neurons and the tight junction. Moreover, the considerably large number of enriched GO and KEGG terms for F8αs2-CN suggests that, perhaps, more focus should be given on αs2-CN (CHAPTER 5).
Lo scopo di questa tesi di dottorato è stato lo studio del background genomico, biologico e fenotipico di caratteri legati al processo di caseificazione nella specie bovina. L’obiettivo primario è stato quello di determinare il background genomico di caratteri tecnologici del latte bovino legati al processo di caseificazione (CAPITOLI da 1 a 3). Per raggiungere questo obiettivo, l’abilità della bovina di produrre formaggio è stata ripartita in 26 fenotipi: 11 caratteri di attitudine casearia e proprietà di coagulazione, comprendenti le tradizionali proprietà di coagulazione del latte (MCP) e nuovi parametri modellizzati di consistenza della cagliata (CFt), e 7 fenotipi di resa in formaggio (CY) e recupero dei nutrienti del latte nella cagliata (REC). Tuttavia, l'elevato numero di variabili necessarie per descrivere la produzione di formaggio bovino pone delle restrizioni nella costruzione di indici di selezione, e quindi nel prendere decisioni di selezione. Per superare il problema della elevata dimensionalità, è stata utilizzata un’analisi fattoriale (FA) per studiare la struttura latente dei 26 caratteri coinvolti nel processo di caseificazione (CAPITOLI 4 e 5). I caratteri MCP includevano le 3 proprietà lattodinamografiche tradizionali basate su singola misurazione dello strumento (RCT: tempo di coagulazione, in min; k20: tempo di rassodamento, in min; a30: consistenza del coagulo (CF) 30 min dopo l'aggiunta del caglio, in mm). I fenotipi CFt comprendevano un set di 6 parametri modellizzati sulla base di 360 dati di CF misurati per ciascun campione di latte (CFp: CF potenziale, in mm; kCF: tasso di rassodamento del coagulo, in % × min-1; kSR: tasso di sineresi, in % × min-1; RCTeq: RCT stimato dal modello; CFmax: massima CF, in mm; tmax: tempo necessario per raggiungere CFmax, in min), delle proteine del latte (%) e del pH. I 3 caratteri CY includevano resa a fresco (% CYCURD), resa in solidi (% CYSOLIDS), e acqua ritenuta nella cagliata (% CYWATER), espresse come percentuale del latte trasformato. Le 4 misure di REC (RECFAT, RECPROTEIN, RECSOLIDS, e RECENERGY) sono state calcolate come rapporto espresso in percentuale tra il valore di nutrienti nella cagliata e il corrispettivo nel latte. L’analisi FA ha considerato tutti i 26 caratteri oggetti di studio, comprendenti produzione e qualità del latte (incluse le frazioni proteiche del latte), parametri CFt e caratteri CY-REC. La metodologia adottata comprendeva analisi di associazione genome-wide (GWAS), accompagnata da analisi di arricchimento genetico e di tipo pathway-based. Le analisi genomiche hanno considerato un totale, 1.152 bovine di razza Bruna Italiana allevate in 85 allevamenti, genotipizzate attraverso il v.2 Illumina SNP50 Beadchip. Le analisi GWAS sono state condotte mediante analisi di regressione a singolo marcatore, fittate utilizzando il pacchetto GenABEL del software R (GRAMMAR-GC). I database Gene Ontology (GO) e Kyoto Encyclopedia of Genes and Genomes (KEGG) sono stati interrogati per le analisi di arricchimento. Nell’analisi GWAS (CAPITOLI 1 e 2) sono stati individuati picchi nitidi sull’autosoma 6 di Bos taurus (BTA) tra 84-88 Mbp, con il picco più alto rilevato a 87,4 Mbp nella regione ospitante i geni della caseina e più precisamente della κ-CN (CSN3). Il marcatore Hapmap52348-rs29024684 (~ 87,4 Mbp), localizzato in prossimità dei geni della caseina su BTA6, ha mostrato una forte associazione con RECFAT (P = 1.91 × 10-15) e CFP (P = 1.62 × 10-17). Sullo stesso cromosoma, è stata trovata evidenza di loci per i caratteri quantitativi a 82,6 e 88,4 Mbp. Su BTA11, il marcatore ARS-BFGL-NGS-104.610 (~ 104,3 Mbp) è risultato fortemente associato con RECPROTEIN (P = 6,07 × 10-36). Oltre a BTA6 e 11, altri SNP situati in altri 15 cromosomi (1, 2, 9, 12, 13, 14, 15, 16, 18, 19, 20, 23, 26, 27 e 28) sono risultati significativamente associati con MCP, CFt e con i caratteri CY-REC. L'analisi di arricchimento e pathway-based (CAPITOLO 3) ha rivelato 21 categorie GO e 17 categorie KEGG significativamente associate (tasso di errore controllato al 5%) con 7 tra i caratteri fenotipici considerati (RCT, RCTeq, kCF, %CYSOLIDS, RECFAT, RECSOLIDS e RECENERGY) e alcune categorie sono risultate in comune tra i caratteri. Le categorie significativamente arricchite includevano vie di segnalazione del calcio, di secrezione salivare, vie metaboliche, di digestione e assorbimento dei carboidrati, di giunzioni occludenti e del fosfatidilinositolo, così come vie legate allo stato di salute della ghiandola mammaria bovina, per un totale di 150 geni situati in tutti i cromosomi tranne 9, 20 e 27. Nella FA (CAPITOLI 4 e 5) sono stati ottenuti dieci Fs mutualmente ortogonali utilizzando una rotazione varimax. I 10 Fs spiegavano il 74% della variabilità originale. Tali Fs erano biologicamente riconducibili a elementi base del processo di trasformazione “dal latte al formaggio". Più precisamente, i primi 4 Fs, ordinati sulla base della varianza spiegata, sono stati in grado di definire la struttura latente della CY percentuale (F1% CY), del processo di CF nel tempo (F2CFt), del rendimento di latte e solidi (F3Yield) e della presenza di azoto (N) nel formaggio (F4Cheese N). Inoltre, 4 Fs (F5αs1-β-CN, F7β-κ-CN, F8αs2-CN, F9αs1-CN-P) erano associati alle caseine del latte (as1-CN, as2-CN, β-CN, κ-CN, e la forma fosforilata as1-CN) e 1 fattore alla proteina del siero α-LA (F10α-LA). É stato inoltre ottenuto un fattore in grado di descrivere lo stato di salute della mammella bovina (F6Udder health), basato principalmente sulla produzione di lattosio e di altri composti azotati e sulle cellule somatiche. In generale, i risultati nell’analisi FA sono risultati coerenti con l’attribuzione del significato biologico dato al fattore. La maggior parte degli Fs è risultata significativamente influenzata dallo stadio di lattazione, seguito dall’ordine di parto. Sono state inoltre riscontrate correlazioni genetiche rilevanti tra i fattori (CAPITOLO 4). Nell’analisi GWAS tutti gli Fs hanno mostrato associazioni significative (P <5 × 10-5), ad eccezione di F5Yield. I picchi elevati su BTA6 (~ 87Mbp) e sulla coda di BTA11 (~ 104Mbp) erano principalmente associati a F6β-κ-CN e F1Cheese N, rispettivamente. Inoltre, 33 termini GO e 6 categorie KEGG sono risultati arricchiti e associati con F1% CY, F4Cheese N, F8αs2-CN e F10α-LA. Le vie di segnalazione biologica descritte dai fattori erano principalmente correlate alle categorie più generali di attività ionica, neuroni e giunzioni occludenti. Poichè un numero considerevole di categorie arricchite GO e KEGG è risultato associato al fattore F8αs2-CN, maggiore attenzione dovrebbe essere posta sulla frazioneαs2-CN (CAPITOLO 5).

Proteins are one of the most important milk quality parameters and the course of coagulation, composition and technological properties of cheese curd depend on them. Proteins form the basis of the structure of Curds and cheese in which milk fat is incorporated, and represent the substrate for enzymes during the ripening of Sjenica cheese. Sjenica cheese is originally produced on the Sjenica-Pester plateau, from whole, fresh, sheep and cow milk, and belongs to the group of white cheeses in brine. Considering the importance of proteins, this research aimed to determine the protein content after cheese making, and to monitor changes after 30, 60, 120, 180 days of ripening, and the extent of degradation using electrophoresis. The results of the research showed that the total protein content was the highest in Sjenica cheese after 30 days of ripening (15.54%), and in Sjenica type cheese after 60 days of ripening (16.55%). After 30, i.e. 60, 120, 180 days of ripening, there is a slight decrease in total protein in both cheeses, as a result of the transfer of soluble nitrogen from the cheese to the ripening brine. After 180 days, the total protein content was 12.78% for Sjenicki and 13.92% for Sjenicki type cheese. Electrophoretic studies showed that protein degradation occurred mostly during the first 60 days of ripening, after that the protein fractions appear in traces as diffuse zones.

Protein-energy depletion (PEW) is the depletion of protein/energy reserves observed in the most advanced stages of chronic kidney disease (CKD). PEW is widespread among patients on chronic dialysis and is associated with adverse clinical outcomes, high morbidity/mortality rates and increased healthcare costs. Cheeses are characterized by a significant content of proteins, milk fat, as well as minerals. Cheese proteins are better absorbed in the human body, compared with dairy. Extractive elements of cheeses have a positive effect on the digestive glands, increase appetite. The nutrients contained in cheese are absorbed by the body almost completely.

The artisanally produced cheese feels a major comeback. Shops specialising in artisanal cheeses are increasingly selling artisanal cheeses made by local producers. In this work we made an assortment of matured cheese, from cow's milk, according to a traditional recipe from Harghita County, Romania. The technological process of obtaining ripened cheeses from cow's milk, studied by us, complies with the traditional technology used for many years. The products obtained were physicochemical evaluated in terms of moisture content, dry matter content, protein content, ash content and fat content in compliance with the methods of the quality standards regarding dairy products. All the results obtained from the physicochemical analysis were compared with the results from the specialized literature. At the same time, a sensory analysis was performed for the matured cow cheese produced by its own production versus other cheese samples from the same category from different areas of Romania. The sensory evaluation was carried out by the method of comparison with unitary score scales, the characteristics pursued being: the appearance and shape of the product, the consistency of the product, the color of the product, the aroma of the product and the taste of the product.

Objective: to consider the issues of a special group of protein, easily digestible dairy products - cheeses, according to their nutritional and biological value, production technology on the example of Gouda cheese. To study the features of technology and the main stages of the production process, with consideration of the technological scheme of mechanized production of Gouda cheese.

Listeria monocytogenes are bacteria that cause listeriosis, a disease which is very severe in vulnerable people. Vulnerable people include pregnant women, people over 65 years of age, infants, and those with a weakened immune system. While most semi-soft cheeses do not let L. monocytogenes grow, blue cheeses may be an exception, and pose a risk to vulnerable groups. L. monocytogenes is widespread in the environment and can grow at refrigeration temperatures. This makes it a particular problem in ready-to-eat foods such as cheese. It can also remain in the environment in food factories for several years as it can be difficult to remove. Foodborne listeriosis is a relatively rare illness in comparison to other foodborne diseases. A search found two potential listeriosis outbreaks and one individual case may have been caused by blue cheese worldwide. No listeriosis illnesses due to blue cheese were identified in the UK. Blue cheese is not frequently consumed by vulnerable consumers. When consumed, it is usually in low amounts. Published data from Scottish local authorities and the Food Standards Agency suggest that overall percentage of blue cheeses contaminated with L. monocytogenes in the UK is low. A search of the scientific literature on contamination in blue cheese from European countries found that most of these studies examined Gorgonzola cheese. The rinds of Gorgonzola were much more likely to be contaminated than the centre of the cheese. Research also shows that the acidic levels and levels of moisture in blue cheese can support L. monocytogenes growth. Most of these studies showed only a small amount of bacterial growth in the centre of the cheese.

COVID-19, caused by the SARS-CoV-2 virus, was first reported in China in December 2019. The virus has spread rapidly around the world and is currently responsible for 500 million reported cases and over 6.4 million deaths. A risk assessment published by the Foods Standards Agency (FSA) in 2020 (Opens in a new window) concluded that it was very unlikely that you could catch coronavirus via food. This assessment included the worst-case assumption that, if food became contaminated during production, no significant inactivation of virus would occur before consumption. However, the rate of inactivation of virus on products sold at various temperatures was identified as a key uncertainty, because if inactivation does occur more rapidly in some situations, then a lower risk may be more appropriate. This project was commissioned to measure the rate of inactivation of virus on the surface of various types of food and food packaging, reducing that uncertainty. The results will be used to consider whether the assumption currently made in the risk assessment remains appropriate for food kept at a range of temperatures, or whether a lower risk is more appropriate for some. We conducted a laboratory-based study, artificially contaminating infectious SARS-CoV-2 virus onto the surfaces of foods and food packaging. We measured how the amount of infectious virus present on those surfaces declined over time, at a range of temperatures and relative humidity levels, reflecting typical storage conditions. We tested broccoli, peppers, apple, raspberry, cheddar cheese, sliced ham, olives, brine from the olives, white and brown bread crusts, croissants and pain au chocolat. The foods tested were selected as they are commonly sold loose on supermarket shelves or uncovered at deli counters or market stalls, they may be difficult to wash, and they are often consumed without any further processing i.e. cooking. The food packaging materials tested were polyethylene terephthalate (PET1) trays and bottles; aluminium cans and composite drinks cartons. These were selected as they are the most commonly used food packaging materials or consumption of the product may involve direct mouth contact with the packaging. Results showed that virus survival varied depending on the foods and food packaging examined. In several cases, infectious virus was detected for several hours and in some cases for several days, under some conditions tested. For a highly infectious agent such as SARS-CoV-2, which is thought to be transmissible by touching contaminated surfaces and then the face, this confirmation is significant. For most foods tested there was a significant drop in levels of virus contamination over the first 24 hours. However, for cheddar cheese and sliced ham, stored in refrigerated conditions and a range of relative humidity, the virus levels remained high up to a week later, when the testing period was stopped. Both cheddar cheese and sliced ham have high moisture, protein and saturated fat content, possibly offering protection to the virus. When apples and olives were tested, the virus was inactivated to the limit of detection very quickly, within an hour, when the first time point was measured. We suggest that chemicals, such as flavonoids, present in the skin of apples and olives inactivate the virus. The rate of viral decrease was rapid, within a few hours, for croissants and pain au chocolat. These pastries are both coated with a liquid egg wash, which may have an inhibitory effect on the virus. Food packaging materials tested had variable virus survival. For all food packaging, there was a significant drop in levels of virus contamination over the first 24 hours, in all relative humidity conditions and at both 6°C and 21°C; these included PET1 bottles and trays, aluminium cans and composite drinks cartons.

Original objectives: The long term objective of the project is to achieve higher content of protein in the milk of ruminants by modulating the translational machinery in the mammary gland. The first specific aim of the BARD proposal was to characterize responsiveness of various experimental systems to combination of lactogenic hormones and amino acids with particular emphasis on discrimination between the control of total protein synthesis and milk protein synthesis. Based on the results, we planned to proceed by characterizing the stage of protein synthesis in which the stimulation by lactogenic hormones and amino acid occur and finally we proposed to identify which components of the translation machinery are modified. Background to the topic: Milk protein is the most valuable component in milk, both for direct human consumption and for manufacturing cheese and other protein-based products. Attempts to augment protein content by the traditional methods of genetic selection and improved nutritional regimes have failed. The proposal was based on recent results suggesting that the limiting factor for augmenting protein synthesis in the bovine mammary gland is the efficiency of converting amino acids to milk proteins. Major conclusions, solutions, achievements: Insulin and prolactin synergistically stimulate â-casein mRNA translation by cytoplasmatic polyadenylation. The interaction between insulin and prolactin was demonstrated two decades ago as crucial for milk-protein synthesis, but the molecular mechanisms involved were not elucidated. We found in differentiated CID 9 mouse mammary epithelial cells line that insulin and prolactin synergistically increases the rate of milk protein mRNA translation. We focused on â-casein, the major milk protein, and found that the increase in â-casein mRNA translation was reflected in a shift to larger polysomes, indicating an effect on translational initiation. Inhibitors of the PI3K, mTOR, and MAPK pathways blocked insulin-stimulated total protein and â-casein synthesis but not the synergistic stimulation. Conversely, cordycepin, a polyadenylation inhibitor, abolished synergistic stimulation of protein synthesis without affecting insulin-stimulated translation. The poly(A) tract of â-casein mRNA progressively increased over 30 min of treatment with insulin plus prolactin. The 3’-untranslated region of â-casein mRNA was found to contain a cytoplasmic polyadenylation element (CPE), and in reporter constructs, this was sufficient for the translational enhancement and mRNA-specific polyadenylation. Furthermore, insulin and prolactin stimulated phosphorylation of cytoplasmic polyadenylation element binding protein (CPEB) but did not increase cytoplasmic polyadenylation.