Journal articles: 'Freeze-drying processes'

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Nunes, Itaciara Larroza, and Adriana Zerlotti Mercadante. "Encapsulation of lycopene using spray-drying and molecular inclusion processes." Brazilian Archives of Biology and Technology 50, no. 5 (September 2007): 893–900. http://dx.doi.org/10.1590/s1516-89132007000500018.

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This study aimed to obtain encapsulated lycopene in a powder form, using either spray-drying or molecular inclusion with beta -cyclodextrin ( beta -CD) followed by freeze-drying. The encapsulation efficiency using spray-drying ranged from 94 to 96%, with an average yield of 51%, with microcapsules showing superficial indentations and lack of cracks and breakages. Lycopene- beta -CD complexes were only formed at a molar ratio of 1:4, and irregular structures of different sizes that eventually formed aggregates, similar to those of beta -CD, were observed after freeze-drying. About 50% of the initial lycopene did not form complexes with beta -CD. Lycopene purity increased from 96.4 to 98.1% after spray-drying, whereas lycopene purity decreased from 97.7 to 91.3% after complex formation and freeze-drying. Both the drying processes yielded pale-pink, dry, free-flowing powders.

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Carullo, Alessio, and Alberto Vallan. "Measurement uncertainty issues in freeze-drying processes." Measurement 45, no. 7 (August 2012): 1706–12. http://dx.doi.org/10.1016/j.measurement.2012.04.017.

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Ciurzyńska, Agnieszka, Monika Janowicz, Magdalena Karwacka, Sabina Galus, Jolanta Kowalska, and Klaudia Gańko. "The Effect of Hybrid Drying Methods on the Quality of Dried Carrot." Applied Sciences 12, no. 20 (October 20, 2022): 10588. http://dx.doi.org/10.3390/app122010588.

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The study investigated the effect of a combination of drying techniques: convection, microwave, and freeze-drying, on selected physical properties of the dried material (carrot) to determine which form of hybrid drying is the best alternative to traditional freeze-drying. Carrots were dried by freeze-drying, convection-drying, and microwave-drying as well as in hybrid methods: freeze-drying-convection, freeze-drying–microwave as well as convection–freeze-drying or microwave–freeze-drying. The color, porosity, shrinkage, water activity, dry matter content, and internal structure of carrots dried using various methods were examined. The dried samples obtained with the hybrid method were compared with those obtained with a single drying technique. Freeze-drying–microwave-drying (F-M) as an alternative drying method for freeze-drying allowed us to obtain dried material with a water activity similar (p < 0.05) to that of freeze-dried samples, at the same time reducing the duration of the process by 20 h. The combination of convection-drying methods with freeze-drying (K-F) and microwave-drying with freeze-drying (M-F) allowed us to obtain dried material with lower shrinkage than in the case of convection (K) or microwave (M) drying.

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Bullock, Murray S., Francis J. Larney, Sean M. McGinn, and R. César Izaurralde. "Freeze-drying processes and wind erodibility of a clay loam soil in southern Alberta." Canadian Journal of Soil Science 79, no. 1 (February 1, 1999): 127–35. http://dx.doi.org/10.4141/s98-027.

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Freeze-drying has been implicated as a factor causing soil aggregate breakdown on the Canadian Prairies and northern Great Plains. Aggregates of a Dark Brown Chernozemic clay loam soil sampled in October 1993 and January and April 1994 were subjected to repeated cycles of wetting (to 0.1, 0.2 and 0.3 kg kg−1 water contents) freezing, and freeze-drying under laboratory conditions. The October 1993 samples showed less disruption when initially exposed to freeze-drying cycles compared to samples taken in January and April 1994. Using regression analysis, we predicted that 31 freeze-dry cycles were required for the 0.1 kg kg−1 water content aggregates to reach 60% erodible fraction (EF, % aggregates <0.86 mm), 9 cycles for the 0.2 kg kg−1 aggregates and 2 for 0.3 kg kg−1 aggregates. In a field study, conducted over the 1994–1995 winter on a similar clay loam soil, we estimated the number of freeze-drying cycles using large vapour pressure (VPL) and small vapour pressure (VPS) gradients between the soil surface (which had a mean winter water content of ~0.1 kg kg−1) and the atmosphere. With solar energy adjustments, we predicted that the number of freeze-dry cycles required for the soil to reach 60% EF was 60 for VPL and 37 for VPS conditions. The latter number was similar to the 31 cycles predicted in the laboratory study of aggregates at 0.1 water content. Our results demonstrate that freeze-drying is an important overwinter process in the breakdown of soil aggregates and hence wind erosion risk in the Canadian prairie region. Key words: Freeze-drying, wind erosion, erodible fraction

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PETITTI, MIRIAM, ANTONELLO A. BARRESI, and DANIELE L. MARCHISIO. "CFD modelling of condensers for freeze-drying processes." Sadhana 38, no. 6 (December 2013): 1219–39. http://dx.doi.org/10.1007/s12046-013-0155-z.

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Oyinloye, Timilehin Martins, and Won Byong Yoon. "Effect of Freeze-Drying on Quality and Grinding Process of Food Produce: A Review." Processes 8, no. 3 (March 20, 2020): 354. http://dx.doi.org/10.3390/pr8030354.

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Freeze-drying is an important processing unit operation in food powder production. It offers dehydrated products with extended shelf life and high quality. Unfortunately, food quality attributes and grinding characteristics are affected significantly during the drying process due to the glass transition temperature (during drying operation) and stress generated (during grinding operation) in the food structure. However, it has been successfully applied to several biological materials ranging from animal products to plants products owning to its specific advantages. Recently, the market demands for freeze-dried and ground food products such as spices, vegetables, and fruits are on the increase. In this study, the effect of the freeze-drying process on quality attributes, such as structural changes, the influence of glass transition during grinding, together with the effect on grinding efficiency in terms of energy requirement, grinding yield, and morphological changes in the powder as a result of temperature, drying time were discussed. An overview of models for drying kinetics for freeze-dried food sample, and grinding characteristics developed to optimize the drying processes, and a prediction of the grinding characteristics are also provided. Some limitations of the drying process during grinding are also discussed together with innovative methods to improve the drying and grinding processes.

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Xin, Xing, Sinemobong Essien, Kiri Dell, Meng Wai Woo, and Saeid Baroutian. "Effects of Spray-Drying and Freeze-Drying on Bioactive and Volatile Compounds of Smoke Powder Food Flavouring." Food and Bioprocess Technology 15, no. 4 (February 23, 2022): 785–94. http://dx.doi.org/10.1007/s11947-022-02779-3.

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AbstractTransforming liquid smoke to powder form can provide convenience for use and storage. Liquid smoke was prepared by fast pyrolysis technology using a fluidised bed and converted to smoke powder by spray-drying or freeze-drying processes. Both drying processes effectively retained the bioactive compounds in the powder encapsulates with retention efficiencies up to 80%. The bioactive capacities were approximately two times higher than liquid smoke. Spray-drying did not induce thermal damage to the bioactive compounds, and the dominant compounds were retained in the powders. Gas chromatography–mass spectrometry and principal component analysis indicated that the chemical composition was not significantly changed after both drying methods, but small molecular carbonyls, furans and phenols were partially lost. The spray-dried particles had a spherical shape, while freeze-dried particles had irregular shapes because of different powder preparation methods. The particle size of spray-dried powders was in the range of 6.3 to 6.9 µm, while the value for freeze-dried powders was decreased from 580.4 to 134.7 µm by increasing the maltodextrin concentration. The freeze-dried powders performed better in terms of flowability and cohesiveness because of their relatively high density and large particle size. This study revealed that both encapsulation methods could efficiently prepare smoke powder. Spray-drying process would be suitable for large-scale production, while freeze-drying could be used to optimize the encapsulation efficiency of bioactive compounds.

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Brandão, R. J., M. M. Prado, and L. G. Marques. "Analysis of Freeze-Drying and Rehydration of Açai (Euterpe oleracea Martius)." Defect and Diffusion Forum 365 (July 2015): 11–16. http://dx.doi.org/10.4028/www.scientific.net/ddf.365.11.

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The freeze-drying rate is essentially low, since it is controlled by internal moisture diffusion. In addition, the application of vacuum and low temperature during the process presents a higher energy demand. Therefore, the search for new strategies to improve water mobility during freeze-drying constitutes a topic of relevant research. The aim of this work was to evaluate the use of power ultrasound to improve freeze-drying characteristics of açai, quantifying the influence of the applied power on both the drying and rehydration kinetics of the material. Açai (Euterpe oleracea Martius) samples were sonicated with two different frequency levels, 20 kHz and 40 kHz, and two sonication times, 3 min and 10 min. Page’s equation considering internal and external resistances to mass transfer provided a good fit of freeze-drying kinetics, while the Peleg’s equation was found to be suitable for describing the rehydration kinetics of freeze-dried açai. Pretreatment of açai with ultrasound waves was not effective. Ultrasound-induced structural disruption in the açai skin hindered the mass transfer during both freeze-drying and rehydration processes.

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Pang, Yuqi, Xu Duan, Guangyue Ren, and Wenchao Liu. "Comparative Study on Different Drying Methods of Fish Oil Microcapsules." Journal of Food Quality 2017 (2017): 1–7. http://dx.doi.org/10.1155/2017/1612708.

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Microencapsulation is widely used to minimize the oxidation of fish oil products. This study compared the effects of different drying methods, for example, spray drying (SD), freeze drying (FD), and spray freeze drying (SFD) on the microencapsulation of fish oil. Spray drying (SD) is the most common method for producing fish oil microcapsules, and it has low operation cost and short processing time, while the product yield and quality are poor. Freeze drying (FD) can be used to produce oil microcapsules with high quality, but it takes long time and high overall cost for drying. Spray freeze drying (SFD) is a new method for the preparation of microcapsules, which combines the SD and FD processes to obtain high quality powder. The yield of powder reached 95.07% along with porous structure by SFD. The stability and slow-release property of SFD products were better than those of SD and FD, which showed that SFD improved product storage stability and potential digestibility.

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Žepič, Vesna, Erika Š. Fabjan, Marta Kasunič, Romana C. Korošec, Aleš Hančič, Primož Oven, Lidija S. Perše, and Ida Poljanšek. "Morphological, thermal, and structural aspects of dried and redispersed nanofibrillated cellulose (NFC)." Holzforschung 68, no. 6 (August 1, 2014): 657–67. http://dx.doi.org/10.1515/hf-2013-0132.

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Abstract The effects of various drying techniques, such as air, oven, freeze, and spray drying, on the morphological, thermal, and structural behaviors of two different nanofibrillated cellulose (NFC) materials were investigated. Field emission scanning electron microscopy (FE-SEM) observations indicated an interlaced network formation of predominantly in-plane fibrillar orientation for air- and oven-dried samples, while freeze and spray drying resulted in the formation of coarse and fine powder fractions. Comparison of redispersed powders obtained by freeze and spray drying indicated that aggregation phenomena are significantly reduced in freeze-dried specimens. Rheological and sedimentation analysis revealed that the freeze-dried NFC powders are more stable than spray-dried NFC powders when redispersed in water. Aggressive dehydration processes, such as freezing or heating, significantly influence the thermal stability of the dried cellulose samples. On the contrary, the crystallinity properties of dried NFC materials are very similar regardless of the drying treatment.

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Indriyati, Muhammad Miftahul Munir, Muhamad Nasir, and Ferry Iskandar. "Effect of post-treatment drying processes on the optical and photothermal properties of carbon nanodots derived via microwave-assisted method." IOP Conference Series: Earth and Environmental Science 1017, no. 1 (April 1, 2022): 012009. http://dx.doi.org/10.1088/1755-1315/1017/1/012009.

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Abstract Carbon nanodots (CNDs) are considered as potential materials for photothermal applications and can be used as solar absorbers to enhance the absorption and conversion efficiency of solar energy to heat. To meet the criteria as solar absorbers, CNDs were synthesized via microwave heating and dried by two different drying processes, namely freeze drying and oven drying, obtaining CNDs powder with the labeled of CND-FD and CND-OD, respectively. The effect of these two drying methods on the optical and photothermal properties of CNDs was investigated. It was observed that soft and light powders were obtained from freeze drying, while oven drying resulted in shiny and agglomerate particles. Oven drying did not alter the absorption profile of CNDs, but freeze-drying resulted in broader and slightly red-shift absorption compared with that of CNDs colloid before drying. Photoluminescence intensity of CND-FD was only half of that of CND-OD. FTIR analysis revealed that CND-FD contained fewer hydroxyl and hydrophilic amine groups, leading to less hygroscopic nature of CND-FD than CND-OD. Because of its better absorption capability, the presence of CND-FD in water significantly increased the water evaporation rate and evaporation efficiency up to 2.2 kg/m2.h and 84%, respectively, three times higher than that of water without CNDs. With a similar photothermal testing condition, CND-OD resulted in a evaporation rate of only 0.9 kg/m2.h and evaporation efficiency of 36%. It can be noticed that freeze drying is more suitable to dry CNDs powder over oven drying to obtain excellent optical and photothermal properties of CNDs.

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Indriyati, Muhammad Miftahul Munir, Muhamad Nasir, and Ferry Iskandar. "Effect of post-treatment drying processes on the optical and photothermal properties of carbon nanodots derived via microwave-assisted method." IOP Conference Series: Earth and Environmental Science 1017, no. 1 (April 1, 2022): 012009. http://dx.doi.org/10.1088/1755-1315/1017/1/012009.

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Abstract Carbon nanodots (CNDs) are considered as potential materials for photothermal applications and can be used as solar absorbers to enhance the absorption and conversion efficiency of solar energy to heat. To meet the criteria as solar absorbers, CNDs were synthesized via microwave heating and dried by two different drying processes, namely freeze drying and oven drying, obtaining CNDs powder with the labeled of CND-FD and CND-OD, respectively. The effect of these two drying methods on the optical and photothermal properties of CNDs was investigated. It was observed that soft and light powders were obtained from freeze drying, while oven drying resulted in shiny and agglomerate particles. Oven drying did not alter the absorption profile of CNDs, but freeze-drying resulted in broader and slightly red-shift absorption compared with that of CNDs colloid before drying. Photoluminescence intensity of CND-FD was only half of that of CND-OD. FTIR analysis revealed that CND-FD contained fewer hydroxyl and hydrophilic amine groups, leading to less hygroscopic nature of CND-FD than CND-OD. Because of its better absorption capability, the presence of CND-FD in water significantly increased the water evaporation rate and evaporation efficiency up to 2.2 kg/m2.h and 84%, respectively, three times higher than that of water without CNDs. With a similar photothermal testing condition, CND-OD resulted in a evaporation rate of only 0.9 kg/m2.h and evaporation efficiency of 36%. It can be noticed that freeze drying is more suitable to dry CNDs powder over oven drying to obtain excellent optical and photothermal properties of CNDs.

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Vorhauer-Huget, Nicole, David Mannes, Mathias Hilmer, Sebastian Gruber, Markus Strobl, Evangelos Tsotsas, and Petra Foerst. "Freeze-Drying with Structured Sublimation Fronts—Visualization with Neutron Imaging." Processes 8, no. 9 (September 2, 2020): 1091. http://dx.doi.org/10.3390/pr8091091.

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The particular structure of the sublimation front in vacuum freeze-drying of porous media is, in most situations, not accessible at the pore scale. The classical measurement techniques access the process only globally. Knowledge about the structure of the front, however, is necessary for prescriptive analysis of freeze-drying, as it dictates not only drying velocity, drying time, and overall energy consumption, but also the material properties after drying. This is especially relevant in situations in which the freeze-drying process is carried out close to the collapse temperature of the product. We, therefore, study the sublimation of ice with neutron tomography and analyze the spatial formation of the dry space using the example of frozen cylindrical maltodextrin with drying parameters at the limit of material collapse. We show that the sublimation front forms unique fractal structures that differ strongly from the usual form of a flat front. Distinct dry fingers covering the sample, in addition to a fractal peripheral sublimation front, were observed. The findings are important for the understanding of freeze-drying processes and will serve as a basis for the development of microscale models of freeze-drying.

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Werk, T., I. S. Ludwig, J. Luemkemann, J. Huwyler, H. C. Mahler, C. R. Haeuser, and M. Hafner. "New Processes for Freeze-Drying in Dual-Chamber Systems." PDA Journal of Pharmaceutical Science and Technology 70, no. 3 (February 9, 2016): 191–207. http://dx.doi.org/10.5731/pdajpst.2015.006155.

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Tang, Xiaolin (Charlie), and Michael J. Pikal. "Design of Freeze-Drying Processes for Pharmaceuticals: Practical Advice." Pharmaceutical Research 21, no. 2 (February 2004): 191–200. http://dx.doi.org/10.1023/b:pham.0000016234.73023.75.

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Donsì, G., G. Ferrari, and D. I. Matteo. "Utilization of Combined Processes in Freeze-Drying of Shrimps." Food and Bioproducts Processing 79, no. 3 (June 2001): 152–59. http://dx.doi.org/10.1205/096030801750425244.

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Rybak, Katarzyna, Artur Wiktor, Dorota Witrowa-Rajchert, Oleksii Parniakov, and Małgorzata Nowacka. "The Quality of Red Bell Pepper Subjected to Freeze-Drying Preceded by Traditional and Novel Pretreatment." Foods 10, no. 2 (January 22, 2021): 226. http://dx.doi.org/10.3390/foods10020226.

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It has been demonstrated previously in the literature that utilization of PEF or a combination of a pulsed electric field (PEF) and ultrasounds (US) can facilitate dehydration processes and improve the quality of dried products even better than the application of thermal methods such as blanching. The aim of the study was to evaluate the quality of red bell pepper subjected to freeze-drying preceded by blanching or PEF or US treatment applied in a single and combined mode. Furthermore, the freeze-drying was preceded by shock freezing or vacuum freezing performed inside the freeze-dryer as a result of pressure drop during the first stage of freeze-drying. All of the analyzed technological variants enhanced the drying kinetics when compared to the intact material. Freeze-dried bell pepper subjected to non-thermal pretreatment exhibited higher vitamin C, total phenolic and carotenoids content than blanched material despite the fact that blanching reduced drying time the most compared to all other analyzed methods.

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Zou, Zhengzheng, John A. Duley, David M. Cowley, Sarah Reed, Buddhika J. Arachchige, Bhesh Bhandari, Paul N. Shaw, and Nidhi Bansal. "Physicochemical Properties and Whey Proteomes of Camel Milk Powders Produced by Different Concentration and Dehydration Processes." Foods 11, no. 5 (March 1, 2022): 727. http://dx.doi.org/10.3390/foods11050727.

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Camel milk powder production is an alternative to preserve the perishable milk for later-date consumption. However, the impacts of dehydration processes on bioactive compounds in camel milk are largely unknown. Hence, the present study attempted to compare the physicochemical properties and protein profiles of camel milk powders produced by different concentration and dehydration processes. Six camel milk powders were produced by freeze- and spray-drying methods in conjunction with two liquid concentration techniques, namely spray dewatering and reverse osmosis. The results of proteomic analysis showed that direct freeze-dried camel milk powder had the least changes in protein profile, followed by direct spray-dried powder. The camel milk powders that underwent concentration processes had more profound changes in their protein profiles. Among the bioactive proteins identified, lactotransferrin and oxidase/peroxidase had the most significant decreases in concentration following processing. On the contrary, glycosylation-dependent cell adhesion molecule 1, peptidoglycan recognition protein 1, and osteopontin increased in concentration. The results revealed that direct freeze drying was the most ideal method for preserving the bioactive proteins during camel milk powder production. However, the freeze-drying technique has cost and scalability constraints, and the current spray-drying technique needs improvement to better retain the bioactivity of camel milk during powder processing.

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Rybak, Katarzyna, Oleksii Parniakov, Katarzyna Samborska, Artur Wiktor, Dorota Witrowa-Rajchert, and Małgorzata Nowacka. "Energy and Quality Aspects of Freeze-Drying Preceded by Traditional and Novel Pre-Treatment Methods as Exemplified by Red Bell Pepper." Sustainability 13, no. 4 (February 13, 2021): 2035. http://dx.doi.org/10.3390/su13042035.

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Freeze-drying is one of the most expensive and most energy intensive processes applied in food technology. Therefore, there have been significant efforts to reduce the freeze-drying time and decrease its energy consumption. The aim of this work was to analyze the effect of pulsed electric field (PEF), ultrasound (US), and hybrid treatment (PEF-US) and compare them with the effect of blanching (BL) on the freeze-drying kinetics, energy consumption, greenhouse gasses emission, and physical quality of the product. The freeze-drying process was applied to red bell peppers after pretreatment operations. Results showed that application of BL, PEF, US, or PEF-US reduces freeze-drying time and decreases energy consumption. Among the tested methods, the combination of PEF performed at 1 kJ/kg and US was the most effective in reduction of greenhouse gas emission. BL samples exhibited the highest porosity, but from a statistical point of view, most of the PEF-US treated materials did not differ from it. The smallest color changes were noted for US pre-treated bell peppers (ΔE = 9.4), whereas BL, PEF, and PEF-US material was characterized by ΔE of 15.2–28.5. Performed research indicates the application of pre-treatment may improve the sustainability of freeze-drying process and quality of freeze-dried bell pepper.

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Yeh, Yu-Hong, Kuei-Ting Hsu, Chia-Hung Huang, and Wei-Ren Liu. "Facile and Green Process to Synthesize a Three-Dimensional Network Few-Layer Graphene/Carbon Nanotube Composite for Electromagnetic Interference Shielding." Polymers 14, no. 9 (May 5, 2022): 1892. http://dx.doi.org/10.3390/polym14091892.

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We propose an environmentally friendly liquid exfoliation approach and subsequent freeze-drying process for constructing a three-dimensional (3D) carbon-based network by using few-layer graphene (FLG) and carbon nanotubes (CNTs) for electromagnetic interference (EMI) shielding applications. Systematic characterizations—such as X-ray diffraction, scanning electron microscopy, and transmission electron microscopy—as well as Raman characterization and EMI shielding tests were performed. The results indicated that the as-synthesized 3D-FLG/CNT composite obtained through the freeze-drying process exhibited excellent electromagnetic interference shielding. The shielding effect of FLG could be improved from 15 to 22 dB by introducing CNTs. The CNTs inhibited restacking of FLG in the structure. We also compared two drying processes: oven drying and freeze-drying. The freeze-drying technique markedly improved the shielding effect of FLG/CNTs from 22 to 36 dB. The composition-optimized 3D-FLG/CNT composite could be a candidate material for use in EMI shielding.

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Wang, Zhe, Wenkai Zhu, Runzhou Huang, Yang Zhang, Chong Jia, Hua Zhao, Wei Chen, and Yuanyuan Xue. "Fabrication and Characterization of Cellulose Nanofiber Aerogels Prepared via Two Different Drying Techniques." Polymers 12, no. 11 (November 3, 2020): 2583. http://dx.doi.org/10.3390/polym12112583.

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Studies on the influence of drying processes on cellulose nanofiber (CNF) aerogel performance has always been a great challenge. In this study, CNF aerogels were prepared via two different drying techniques. The CNF solution was prepared via existing chemical methods, and the resultant aerogel was fabricated through supercritical CO2 drying and liquid nitrogen freeze-drying techniques. The microstructure, shrinkage, specific surface area, pore volume, density, compression strength, and isothermal desorption curves of CNF aerogel were characterized. The aerogel obtained from the liquid nitrogen freeze-drying method showed a relatively higher shrinkage, higher compression strength, lower specific surface area, higher pore volume, and higher density. The N2 adsorption capacity and pore diameter of the aerogel obtained via the liquid nitrogen freeze-drying method were lower than the aerogel that underwent supercritical CO2 drying. However, the structures of CNF aerogels obtained from these two drying methods were extremely similar.

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Dziki, Dariusz, Renata Polak, Stanisław Rudy, Andrzej Krzykowski, Urszula Gawlik-Dziki, Renata Różyło, Antoni Miś, and Maciej Combrzyński. "Simulation of the process kinetics and analysis of physicochemical properties in the freeze drying of kale." International Agrophysics 32, no. 1 (January 1, 2018): 49–56. http://dx.doi.org/10.1515/intag-2016-0086.

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AbstractInvestigations were performed to study the freeze-drying process of kale (Brassica oleraceaL. varacephala). The process of freeze-drying was performed at temperatures of 20, 40, and 60°C for whole pieces of leaves and for pulped leaves. The kinetics of the freeze-drying of both kale leaves and kale pulp were best described by the Page model. The increasing freeze-drying temperature from 20 to 60°C induced an approximately two-fold decrease in the drying time. Freeze-drying significantly increased the value of the lightness, delta Chroma, and browning index of kale, and had little influence on the hue angle. The highest increase in the lightness and delta Chroma was observed for whole leaves freeze-dried at 20°C. An increase in the drying temperature brought about a slight decrease in the lightness, delta Chroma and the total colour difference. Pulping decreased the lightness and hue angle, and increased browning index. Freeze-drying engendered a slight decrease in the total phenolics content and antioxidant activity, in comparison to fresh leaves. The temperature of the process and pulping had little influence on the total phenolics content and antioxidant activity of dried kale, but significantly decreased the contents of chlorophyllaand chlorophyllb.

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Nowak, Dorota, and Ewa Jakubczyk. "The Freeze-Drying of Foods—The Characteristic of the Process Course and the Effect of Its Parameters on the Physical Properties of Food Materials." Foods 9, no. 10 (October 18, 2020): 1488. http://dx.doi.org/10.3390/foods9101488.

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Freeze-drying, also known as lyophilization, is a process in which water in the form of ice under low pressure is removed from a material by sublimation. This process has found many applications for the production of high quality food and pharmaceuticals. The main steps of the freeze-drying process, such as the freezing of the product and primary and secondary drying, are described in this paper. The problems and mechanisms of each step of the freeze-drying process are also analyzed. The methods necessary for the selection of the primary and secondary end processes are characterized. The review contains a description of the effects of process conditions and the selected physical properties of freeze-dried materials, such as structural properties (shrinkage and density porosity), color, and texture. The study shows that little attention is given to the mechanical properties and texture of freeze-dried materials obtained from different conditions of the lyophilization process.

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Harguindeguy, Maitê, and Davide Fissore. "Micro Freeze-Dryer and Infrared-Based PAT: Novel Tools for Primary Drying Design Space Determination of Freeze-Drying Processes." Pharmaceutical Research 38, no. 4 (March 8, 2021): 707–19. http://dx.doi.org/10.1007/s11095-021-03023-x.

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Abstract Purpose Present (i) an infrared (IR)-based Process Analytical Technology (PAT) installed in a lab-scale freeze-dryer and (ii) a micro freeze-dryer (MicroFD®) as effective tools for freeze-drying design space calculation of the primary drying stage. Methods The case studies investigated are the freeze-drying of a crystalline (5% mannitol) and of an amorphous (5% sucrose) solution processed in 6R vials. The heat (Kv) and the mass (Rp) transfer coefficients were estimated: tests at 8, 13 and 26 Pa were carried out to assess the chamber pressure effect on Kv. The design space of the primary drying stage was calculated using these parameters and a well-established model-based approach. The results obtained using the proposed tools were compared to the ones in case Kv and Rp were estimated in a lab-scale unit through gravimetric tests and a thermocouple-based method, respectively. Results The IR-based method allows a non-gravimetric estimation of the Kv values while with the micro freeze-dryer gravimetric tests require a very small number of vials. In both cases, the obtained values of Kv and Rp, as well as the resulting design spaces, were all in very good agreement with those obtained in a lab-scale unit through the gravimetric tests (Kv) and the thermocouple-based method (Rp). Conclusions The proposed tools can be effectively used for design space calculation in substitution of other well-spread methods. Their advantages are mainly the less laborious Kv estimation process and, as far as the MicroFD® is concerned, the possibility of saving time and formulation material when evaluating Rp.

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Roque, Marjorie, Danilo Geraldes, Caroline da Silva, Mônica Oliveira, and Laura Nascimento. "Long-Circulating and Fusogenic Liposomes Loaded with Paclitaxel and Doxorubicin: Effect of Excipient, Freezing, and Freeze-Drying on Quality Attributes." Pharmaceutics 15, no. 1 (December 27, 2022): 86. http://dx.doi.org/10.3390/pharmaceutics15010086.

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Liposomes can increase plasma half-life, enhance targeting, and diminish the side-effects of loaded drugs. On the downside, physical and chemical instabilities of dispersions often result in a reduced lifespan, which limits their availability on the market. Solid formulations obtained by freeze-drying can immobilize vesicles and provide extended shelf life. For both processes, the choice of excipients and process parameters are crucial to protect the carrier layers against tension caused by freezing and/or dehydration. The aim of this work is to evaluate the influence of freezing and drying parameters, besides excipient choice, to obtain solid long-circulating and fusogenic liposomes (LCFL-PTX/DXR) co-encapsulating paclitaxel (PTX) and doxorubicin (DXR) at a synergistic ratio (1:10). Methods: LCFL-PTX/DXR was evaluated by freeze-drying microscopy (glass transition, Tg’), differential scanning calorimetry (collapse temperature, Tc), freeze-thawing and freeze-drying processes. Freeze-dried samples were evaluated by thermogravimetry (residual moisture) and the resuspended liposomes were characterized in terms of size, polydispersity index (PI), zeta potential (ZP), and drug content. Liposomes morphology was evaluated by cryomicroscopy. Results: Trehalose protected PTX cargo upon freeze-thawing and more than 80% of the original DXR retention. The formulations with trehalose resulted in a cake with 5–7% of moisture content (200–240 nm); 44–60% of PTX retention, and 25–35% of DXR retention, with the variations caused by cryoprotector concentration and process changes. Conclusions: Trehalose protected liposome integrity, maintaining PTX retention and most of DXR upon freeze-thawing. Freeze-drying reduced the retention of both drugs inside all liposomes, whereas formulation with trehalose presented minor losses. Therefore, this frozen formulation is an alternative product option, with no need for manipulation before use.

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Chen, Weijun, Hoi Tung Chiu, Ziqian Feng, Evelyne Maes, and Luca Serventi. "Effect of Spray-Drying and Freeze-Drying on the Composition, Physical Properties, and Sensory Quality of Pea Processing Water (Liluva)." Foods 10, no. 6 (June 17, 2021): 1401. http://dx.doi.org/10.3390/foods10061401.

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Spray-drying and freeze-drying can extend the shelf life and improve the transportability of high-nutritional foods such as Liluva (processing water of legumes). Nonetheless, the effects of these processes on nutrition, physiochemical properties, and sensory quality are unknown. In this study, particle sizes, protein profiles, colour, and preliminary sensory profile of pea powder samples were determined by Mastersizer 3000, protein gels, chroma meter, and 9-point hedonic scale, respectively. Results indicated that no significant difference was found in the molecular weight distribution of protein bands in pea water and sensory profile after drying. Fibre content in pea water after spray-drying was higher while soluble carbohydrates and minerals were lower than those after freeze-drying. Spray-drying decreased pea water’s lysine content, particle size, redness colour, and yellowness colour, while it increased its light colour; however, freeze-drying showed the opposite results. Overall, spray-drying could be a better drying technology that can be applied to dry pea water. Further experiments are required, however, to determine the influence of drying technologies on emulsifying activity.

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Oliveira-Alves, Sheila C., Fábio Andrade, Inês Prazeres, Andreia B. Silva, Jorge Capelo, Bernardo Duarte, Isabel Caçador, Júlio Coelho, Ana Teresa Serra, and Maria R. Bronze. "Impact of Drying Processes on the Nutritional Composition, Volatile Profile, Phytochemical Content and Bioactivity of Salicornia ramosissima J. Woods." Antioxidants 10, no. 8 (August 20, 2021): 1312. http://dx.doi.org/10.3390/antiox10081312.

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Salicornia ramosissima J. Woods is a halophyte plant recognized as a promising natural ingredient and will eventually be recognized a salt substitute (NaCl). However, its shelf-life and applicability in several food matrices requires the use of drying processes, which may have an impact on its nutritional and functional value. The objective of this study was to evaluate the effect of oven and freeze-drying processes on the nutritional composition, volatile profile, phytochemical content, and bioactivity of S. ramosissima using several analytical tools (LC-DAD-ESI-MS/MS and SPME-GC-MS) and bioactivity assays (ORAC, HOSC, and ACE inhibition and antiproliferative effect on HT29 cells). Overall, results show that the drying process changes the chemical composition of the plant. When compared to freeze-drying, the oven-drying process had a lower impact on the nutritional composition but the phytochemical content and antioxidant capacity were significantly reduced. Despite this, oven-dried and freeze-dried samples demonstrated similar antiproliferative (17.56 mg/mL and 17.24 mg/mL, respectively) and antihypertensive (24.56 mg/mL and 18.96 mg/mL, respectively) activities. The volatile composition was also affected when comparing fresh and dried plants and between both drying processes: while for the freeze-dried sample, terpenes corresponded to 57% of the total peak area, a decrease to 17% was observed for the oven-dried sample. The oven-dried S. ramosissima was selected to formulate a ketchup and the product formulated with 2.2% (w/w) of the oven-dried plant showed a good consumer acceptance score. These findings support the use of dried S. ramosissima as a promising functional ingredient that can eventually replace the use of salt.

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Silva, Semirames do N., Francisco de Assis C. Almeida, Josivanda P. Gomes, Antônio Jackson R. Barroso, Polyana B. Silva, Bruno A. Melo, Luís Paulo F. R. Silva, et al. "Production and Physical and Physicochemical Characterization Powder in Natura and Freeze-Dried of Moringa Seeds." Journal of Agricultural Science 11, no. 9 (June 30, 2019): 11. http://dx.doi.org/10.5539/jas.v11n9p11.

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To apply low temperatures, different of other processes, maintain the structure of products and better preserve the thermosensitive components, the freeze-drying has called attention of various researchers. Aimed with the research to produce and characterize the powder in natura obtained by seeds of moringa, elaborate different pastes with addiction of 20, 30, 40 and 50 mL of distilled water, freeze-dry it, characterize it physical and physicochemical and select the best powder. The freeze-drying was produced through a benchtop freeze dryer. After drying it, from the powder were determined the real density, bulk density, compacted density, porosity, compressibility index, Hausner factor, hygroscopicity, solubility, color, moisture content and water activity, ashes, total acidity, pH, proteins, lipids and carbohydrates. The in natura powder was classified as non-hygroscopic, high solubility in water, low moisture content and water activity, high protein, lipids, carbohydrates and low acidity. Freeze-drying was presented as an appropriate method for the preservation of moringa constituents, with a formula selected with the addition of 50 mL of water.

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Juckers, Alex, Petra Knerr, Frank Harms, and Jochen Strube. "Emerging PAT for Freeze-Drying Processes for Advanced Process Control." Processes 10, no. 10 (October 12, 2022): 2059. http://dx.doi.org/10.3390/pr10102059.

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Lyophilization is a widely used drying operation, but long processing times are a major drawback. Most lyophilization processes are conducted by a recipe that is not changed or optimized after implementation. With the regulatory demanded quality by design (QbD) approach, the process can be controlled inside an optimal range, ensuring safe process conditions. Process analytical technology (PAT) is crucial because it allows real-time monitoring and is part of a control strategy. In this work, emerging PAT (manometric temperature measurement (MTM), comparative pressure measurement, heat flux sensors, and ice ruler) are used for measurements during the freeze-drying process, and their potential for implementation inside a control strategy is outlined.

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Siebert, Tim, Marcus Zuber, Elias Hamann, Tilo Baumbach, Heike P. Karbstein, and Volker Gaukel. "Micro-CT visualization of structure development during freeze-drying processes." Drying Technology 38, no. 3 (February 21, 2019): 376–84. http://dx.doi.org/10.1080/07373937.2019.1572619.

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Palacio, Ana, Yessica Gutiérrez, Diego Rojas, Lucía Atehortúa, and Paola Zapata. "Viability of Basidiomycete fungal strains under different conservation methods: Crypreservation vs. freeze-drying processes." Actualidades Biológicas 36, no. 100 (October 18, 2017): 13–21. http://dx.doi.org/10.17533/udea.acbi.329101.

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Four basidiomycete fungi; Agaricus blazei Murrill (Agaricomycetideae), Ganoderma lucidum (W.Curt.: Fr.) P. Karst., Grifola frondosa (Dicks.: Fr.) S.F. Gray (Higher Basidiomycetes), and Pleurotus pulmonarius (Fr.) Quél. (Agaricomycetideae) were evaluated using three conservation methods for 12 months, recording their viability in order to establish the best conservation method. Growth kinetics, biomass, and polysaccharide production were studied. The conservation methods implemented included: distilled wáter at 24 ºC; sawdust and rice bran with 10% glicerol at -20 ºC, sawdustand rice bran with 10% glicerol at -80 ºC; and freeze-drying of biomass with trehalose or simmed milk. After conducting the analysis of the results after 12 months of conservation, we determined that the distilled water treatment at 24 ºC was the best conservation method with the highest percentage of recoverability, at 83.3% during the 12 month, followed by the cryoconservation treatment at 80º C, where 75% were recovered with no negative effects on biomass and polysaccharide production. The -20 ºC and freeze-drying treatments were not effective; with cryoconservation at -20 ºC treatment, strain recovery only occurred during the first month and with freeze-drying it was not possible to recover any strains during the entire 12-month period evaluated.

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Sroy, Sengly, Fátima A. Miller, Joana F. Fundo, Cristina L. M. Silva, and Teresa R. S. Brandão. "Freeze-Drying Processes Applied to Melon Peel: Assessment of Physicochemical Attributes and Intrinsic Microflora Survival during Storage." Foods 11, no. 10 (May 21, 2022): 1499. http://dx.doi.org/10.3390/foods11101499.

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Melon peel is recognized as a source of healthy nutrients and oxidant compounds. Being considered a non-edible part with no profit value, large amounts of melon rinds are discharged by fruit industries. Innovative food ingredients with potential health benefits may arise if these parts were conveniently transformed. The objective was to freeze-dry small melon peel cubes to attain a potential edible matrix. An ozone pre-treatment was applied seeking decontamination purposes and quality retention. The effect of these processes was assessed in terms of physicochemical parameters (moisture content, water activity and color), bioactive compounds (total phenolics, vitamin C and chlorophylls) and antioxidant capacity, during 7 weeks of storage at room temperature. Intrinsic microflora (mesophylls, yeasts and molds) were also monitored. Results showed that the freeze-drying process allowed retention of the most bioactive compounds analyzed, except for total phenolic content. In this case, the ozone pre-treatment was important for phenolics preservation. During the storage period, ozonated samples presented a higher content of bioactive compounds. In terms of microflora, the ozone and freeze-drying effects were not significant. Freeze-drying proved to be a suitable preservation method for melon peel. The ozone impact was not relevant in terms of decontamination.

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Lin, Chun-Ping, and Shu-Yao Tsai. "Differences in the Moisture Capacity and Thermal Stability of Tremella fuciformis Polysaccharides Obtained by Various Drying Processes." Molecules 24, no. 15 (August 6, 2019): 2856. http://dx.doi.org/10.3390/molecules24152856.

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We compared the proportions and differences in the polysaccharides of Tremella fuciformis (Berkeley) after drying them by various processes, such as 18 °C cold air, 50 °C hot air, and freeze-drying. We also focused on the moisture capacity kinetic parameters of Tremella fuciformis polysaccharides using various thermal analyses, including differential scanning calorimetry and thermogravimetric techniques. Erofeev’s kinetic and proto-kinetic equations, utilized for kinetic model simulation, can predict the moisture capacity due to the thermal effect. Among the various drying processes, cold air-drying had the highest molecular weight of 2.41 × 107 Da and a moisture content of 13.05% for Tremella fuciformis polysaccharides. Overall, the freeze-dried products had the best thermal decomposition properties under the conditions of a closed system, with an air or nitrogen atmosphere, and had an excellent moisture capacity of around 35 kJ/kg under a closed system for all samples.

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Santo, Edson Francisco do Espírito, Leandro Kanamaru Franco de Lima, Ane Pamela Capucci Torres, Gabriela de Oliveira, and Elisa Helena Giglio Ponsano. "Comparison between freeze and spray drying to obtain powder Rubrivivax gelatinosus biomass." Food Science and Technology 33, no. 1 (February 25, 2013): 47–51. http://dx.doi.org/10.1590/s0101-20612013005000008.

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The use of colorants in products of animal origin is justified by the improvement in the color of foods since this attribute is considered a quality criterion. These additives can be produced using industrial effluents as substrates and appropriate organisms, such as Rubrivivax gelatinosus. Oxycarotenoids represent a class of carotenes responsible for the pigmentation of animals and vegetables. R. gelatinosus grows in fish industry effluent with the resulting production of a bacterial biomass containing oxycarotenoids. The purpose of this study was to compare the use of two drying processes - spray and freeze drying - to obtain powder biomass in terms of the process parameters (yield, productivity, and product recovery) and the product characteristics (color, proximate composition, and oxycarotenoids). No difference was detected in the yield between these techniques, while productivity was higher using spray drying. Higher product recovery and moisture were achieved with freeze drying, while ash was higher with spray drying. The freeze dried biomass was redder, darker and less saturated than the spray dried biomass. No difference in oxycarotenoids was detected between the biomasses. Although it results in lower recovery rate, spray drying was faster and more productive, and it provided the same yield as freeze drying, which makes it the method of choice for obtaining R. gelatinosus biomass.

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Xu, Qing, Ruixin Wang, Fan Zhang, Ruifang Wang, Long Wu, and Bo Lin. "Spray Freezing Coating on the Carrier Particles for Powder Preparation." Coatings 12, no. 7 (June 24, 2022): 896. http://dx.doi.org/10.3390/coatings12070896.

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Carrier particle spray freeze-drying is a new technology with high added value for thermosensitive powder spray freeze-drying. The technology includes the following steps: atomization, coating, freezing, and drying. Due to the action of carrier particles, the condensation of frozen droplets in the conventional spray freeze-drying process is overcome. However, there are many influencing factors involved in the process of freezing coating. The mechanism of the complex droplet collision freezing process still needs to be studied. In this paper, from the perspective of spray freezing coating after atomized droplets collide with low-temperature carrier particles, the coating process and freezing process of single droplets impacting the sphere are analyzed microscopically. The freezing coating processes of static and dynamic carrier particles are reviewed. Moreover, the surface evaluation of powder and equipment development for creating powder products is discussed.

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Saha, Madhumita. "STUDY OF PHYSICOCHEMICAL PROPERTIES OF CAPSICUM POWDER BY DIFFERENT DRYING TECHNIQUES." Journal of Medical pharmaceutical and allied sciences 10, no. 4 (August 15, 2021): 3110–14. http://dx.doi.org/10.22270/jmpas.v10i4.1386.

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The objective of this study was to analyse the effects of phytochemical parameter, physical parameter, color, and sensory analysis in green capsicum by different drying processes (microwave, freeze, and hot air drying). Results showed an increase in microwave output power (600W), decreased drying time, moisture content, Chroma, and bulk density values. The Freeze drying process significantly improved the lightness of dried capsicum. Due to take less time for the Microwave drying technique, phytochemical parameters are intact in capsicum; on the other side, color degradation has been occurred due to the Maillard reaction (L*=29.34±0.08, a*=6.98±0.09,b*=15.36±0.10). Bulk density (0.335±0.01) and dispersibility (40±2.00%) were highest in Microwave drying powder. The capsaicin content of dried capsicum was higher than the fresh capsicum sample, but compared to the different drying techniques, the Microwave drying sample has higher capsaicin content than the Hot air drying and Freeze-drying samples. The lower capsaicin content in fresh capsicum may occur due to the catalytic activity of the peroxidase enzyme. The capsaicin content of all dried capsicum varied between 1.91±0.05 and 3.31±0.16 mg/100 g. In this research, the Microwave drying powder of capsicum was the best product for its highest antioxidant content and other physical properties.

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Jakubczyk, Ewa, and Aleksandra Jaskulska. "The Effect of Freeze-Drying on the Properties of Polish Vegetable Soups." Applied Sciences 11, no. 2 (January 11, 2021): 654. http://dx.doi.org/10.3390/app11020654.

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The aim of this study was to investigate selected physical and biochemical properties of four vegetable freeze-dried soups. The water content, water activity, pH, color parameters, antioxidant activity (EC50), total polyphenolic content of fresh tomato, pumpkin, beetroot, and cucumber, and freeze-dried soups were measured. Sensory analysis was applied to compare sensory attributes of fresh and rehydrated soups. The sorption isotherms of freeze-dried soups were obtained with the application of the static and dynamic vapor sorption (DVS) method. The application of the freeze-drying method enabled the obtaining of dry soups with a low water content of 2–3%. The drying caused a significant change of color of all soups. The redness of soups decreased after drying for the beetroot soups from +39.64 to +21.91. The lower chroma value of 25.98 and the highest total color change ΔE*ab = 36.74 were noted for freeze-dried beetroot soup. The antioxidation activity and total polyphenolic content were reduced after drying, especially for the cucumber and tomato soups. The Peleg model was selected to describe the sorption isotherms of dried soups. The sorption isotherm of freeze-dried cucumber and beetroot soups had a sigmoidal shape of type II. The shape of the moisture sorption isotherm for freeze-dried tomato and pumpkin soups corresponded more with type III isotherms. The DVS method can be used to characterize the moisture sorption isotherms of freeze-dried products.

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Hilmer, Mathias, Sebastian Gruber, and Petra Foerst. "Development of a Freeze-Drying Stage for In-Situ µ-CT Measurements." Processes 8, no. 7 (July 18, 2020): 869. http://dx.doi.org/10.3390/pr8070869.

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This paper shows the development of a freeze-drying stage for in-situ μ-CT measurements. The stage can operate in a temperature range of −40 °C up to 70 °C, and a pressure range from atmospheric pressure to 7 Pa at the sample holder. To get the best visualization of the probe, it is fundamental that the materials around the sample holder are not absorbing most of the radiation. For this reason, we built an axial symmetrical stage built out of polyetheretherketon (PEEK). A test of the stage by different freeze-drying experiments with maltodextrin and sucrose particles and solutions demonstrated its suitability to visualize the freeze-drying processes in-situ. It was possible to track the drying front during the process by radiographic and tomographic measurements, as well as to visually resolve the ice crystals and porous structure in tomographic measurements. Using different samples and process parameters, we showed that the freeze-drying stage is not only suitable for in-situ µ-CT measurements, but also allows us to use the stage for other imaging methods such as neutron imaging, and for any sample where a controlled environment is needed.

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Janiszewska, E., D. Witrowa-Rajchert, M. Kidoń, and J. Czapski. "Effect of the applied drying method on the physical properties of purple carrot pomace." International Agrophysics 27, no. 2 (March 1, 2013): 143–49. http://dx.doi.org/10.2478/v10247-012-0079-6.

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Abstract The aim of the study was to determine the effect of different drying methods on selected physical properties of pomace obtained from purple carrot cv. Deep Purple. Drying was performed using four methods: convective, microwave-convective, infrared-convective and freeze-drying. The freeze-dried material had the lowest apparent density (422 kg m-3), which was caused by slight shrinkage, and indicated high porosity. Apparent density was almost three times greater in dried materials produced using the other drying methods as compared to the freeze-dried variants. Freeze-dried pomace adsorbed vapour more quickly than the other dried variants, which was caused by its high porosity and relatively low degree of structural damage. Rehydration characteristicswere significantly affected by the dryingmethod. The highest mass increase and losses of soluble substance were recorded for the freeze-dried samples. Conversely, the traditional convective drying method resulted in the lowest mass increase and soluble substance leaching. A positive linear correlation was found between the loss of soluble dry substance components and the absorbance of liquid obtained during rehydration.

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Telaumbanua, A. S., J. N. W. Karyadi, Pravitajaty, A. N. I. Kusumastuti, K. Ma’Rufah, and D. Ayuni. "Physical quality analysis of drying beluntas leaves (Pluchea indica L.) using variations of drying methods." IOP Conference Series: Earth and Environmental Science 922, no. 1 (November 1, 2021): 012053. http://dx.doi.org/10.1088/1755-1315/922/1/012053.

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Abstract Beluntas leaves are medicinal plants with pharmacological effects, such as antioxidant, antidiarrheal, antidiabetic, and antibacterial. Drying is one of the processes before the beluntas leaves are consumed. However, drying could degrade the quality of beluntas leaves. This research aims to investigate the impact of drying conditions on the physical qualities of dried beluntas leaves. Beluntas leaves with a moisture content of 83-90% were dried using drying methods, namely the greenhouse effect dryer (ERK), cabinet dryer (CD) at 40, 50, 60, and 70°C, and freeze dryer (FD) at 35, 45, and 55°C. The physical parameters measured were moisture content, color, shrinkage, rehydration ratio, and bulk density. The results showed that the final moisture content of the dried beluntas leaves were 8.40; 4.92-10.70; 4.73-6.77%w.b for ERK, CD, and FD, respectively. Page’s model was suitable for explaining the changes in moisture ratio during the drying process (R 2 = 0.9934 − 0.9999). The freeze-drying method can preserve the leaves’ color and obtain the lowest moisture content with a low drying temperature compared to other methods. Freeze-dried beluntas leaves also exhibited the highest rehydration ratio, which was 2.03 – 2.25.

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Feng, Chuting, Penggang Ren, Zhen Li, Wenzhen Tan, Hua Zhang, Yanling Jin, and Fang Ren. "Graphene/waste-newspaper cellulose composite aerogels with selective adsorption of organic dyes: preparation, characterization, and adsorption mechanism." New Journal of Chemistry 44, no. 6 (2020): 2256–67. http://dx.doi.org/10.1039/c9nj05346h.

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Lin, Sui. "Thermal control of freeze-drying processes in a porous medium with predetermined rate of drying." International Journal of Refrigeration 18, no. 3 (March 1995): 161–67. http://dx.doi.org/10.1016/0140-7007(94)00006-j.

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Dziki, Dariusz. "Recent Trends in Pretreatment of Food before Freeze-Drying." Processes 8, no. 12 (December 16, 2020): 1661. http://dx.doi.org/10.3390/pr8121661.

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Drying is among the most important processes and the most energy-consuming techniques in the food industry. Dried food has many applications and extended shelf life. Unlike the majority of conventional drying methods, lyophilization, also known as freeze-drying (FD), involves freezing the food, usually under low pressure, and removing water by ice sublimation. Freeze-dried materials are especially recommended for the production of spices, coffee, dried snacks from fruits and vegetables and food for military or space shuttles, as well as for the preparation of food powders and microencapsulation of food ingredients. Although the FD process allows obtaining dried products of the highest quality, it is very energy- and time consuming. Thus, different methods of pretreatment are used for not only accelerating the drying process but also retaining the physical properties and bioactive compounds in the lyophilized food. This article reviews the influence of various pretreatment methods such as size reduction, blanching, osmotic dehydration and application of pulsed electric field, high hydrostatic pressure or ultrasound on the physicochemical properties of freeze-dried food and drying rate.

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Singha Roy, Pritha, Gaurab Joarder, Saibal Debnath, and Avisek Pahari. "A REVIEW OF THE INNOVATIVE DRYING TECHNOLOGIES FOR BIOPHARMACEUTICALS." International Journal of Advanced Research 10, no. 05 (May 31, 2022): 1100–1111. http://dx.doi.org/10.21474/ijar01/14820.

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Reviewing data from the previous twenty to twenty-five years reveals that bio-pharmaceuticals are a sudden, dramatic, and incredibly significant finding in progressively enhancing the quality of life for patients with different kinds of malignancies, auto-immune illnesses, genetic disorders, etc. Drying technologies are a required manufacturing step in the pharmaceutical industry/production unit, and an understanding of drying technologies and how to use them is now an absolute must. With the increased demand for biopharmaceuticals, it is essential to reduce production costs without sacrificing product safety, quality, or effectiveness. The predominant commercial method for generating solid biopharmaceuticals is batch freeze-drying. However, freeze-drying is expensive compared to other procedures and is not ideal for lengthy working hours, in addition to requiring a large initial capital investment and significant energy consumption, resulting in high total expenses. This article discusses innovative drying methods for parenteral biopharmaceuticals. Spin-freeze drying, spray drying, and LynfinityÂ® Technology enable continuous manufacturing, while PRINTÂ® Technology and MicroglassificationTM manage dry particle characteristics. As a consequence, certain drying processes may need less validation. Process Analytical Technology (PAT) and offline dramatisation may give extra information on CPPs and CQAs during biopharmaceutical manufacture. These processing approaches might boost biopharmaceutical product production while reducing expenses.

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Rother, Matthias, Philipp Steimle, Volker Gaukel, and Heike P. Schuchmann. "How to Meet the Freeze Drying Standard in Combined Drying Processes: Pre and Finish Drying of Carrot Dice." Drying Technology 29, no. 3 (February 28, 2011): 266–77. http://dx.doi.org/10.1080/07373937.2010.483564.

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Liaotrakoon, Wijitra, Vachiraya Liaotrakoon, and Wanpa Wongsaengthama. "Impact of Different Drying Methods on Nutritional, Colour Change, Solubility and Microbial Count of Selected Herbal Plant Powders." International Journal of Food Studies, no. 2 (October 18, 2022): 275–86. http://dx.doi.org/10.7455/ijfs/11.2.2022.a2.

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The research aimed to study the effect of drying processes (spray and freeze drying), and feed concentrations (80%, 65% and 50% of plant in water, w/w) on physicochemical and microbiological characteristics of star gooseberry (Sauropus androgynus), ceylon spinach (Basella alba), and cowslip creeper (Telosma minor). After drying, the powder recovery of herbal plant powders was up to 77.47%. The aw and moisture content of spray-dried powder (SDP) were lower than that of freeze-dried powder (FDP). The drying method did not significantly affect nutritional values of both powders, whereas the feed concentrations markedly affected the nutritional values of the powders. The fibre and fat contents of powder prepared from 80% feed concentration had the highest values (p<0.05). The dried star gooseberry powder was rich in protein (13.01-16.81%) and fibre (5.03-5.52%). The colour of FDP represented a smaller change than that of SDP. The dried powders prepared by 80% showed the highest solubility, up to 85.44%. The microbial counts of SDP were lower than that of FDP. The colour might well have been preserved by freeze drying, whereas a low moisture and microbial count were likely due to the spray drying.

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Juckers, A., P. Knerr, F. Harms, and J. Strube. "Emerging process analytical technology (PAT) for characterization of freeze‐drying processes." Chemie Ingenieur Technik 94, no. 9 (August 25, 2022): 1287. http://dx.doi.org/10.1002/cite.202255089.

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Bae, Soo Hwan, Jin Hyun Nam, Chi Sung Song, and Charn-Jung Kim. "A Numerical Model for Freeze Drying Processes with Infrared Radiation Heating." Numerical Heat Transfer, Part A: Applications 58, no. 5 (August 27, 2010): 333–55. http://dx.doi.org/10.1080/10407782.2010.508437.

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Guastaferro, Mariangela, Lucia Baldino, Ernesto Reverchon, and Stefano Cardea. "Production of Porous Agarose-Based Structures: Freeze-Drying vs. Supercritical CO2 Drying." Gels 7, no. 4 (November 5, 2021): 198. http://dx.doi.org/10.3390/gels7040198.

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In this work, the effect of two processes, i.e., freeze-drying and supercritical CO2 (SC-CO2) drying, on the final morphology of agarose-based porous structures, was investigated. The agarose concentration in water was varied from 1 wt% up to 8 wt%. Agarose cryogels were prepared by freeze-drying using two cooling rates: 2.5 °C/min and 0.1 °C/min. A more uniform macroporous structure and a decrease in average pore size were achieved when a fast cooling rate was adopted. When a slower cooling rate was performed instead, cryogels were characterized by a macroporous and heterogenous structure at all of the values of the biopolymer concentration investigated. SC-CO2 drying led to the production of aerogels characterized by a mesoporous structure, with a specific surface area up to 170 m2/g. Moreover, agarose-based aerogels were solvent-free, and no thermal changes were detected in the samples after processing.

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Schmid, Benjamin, Sofia Navalho, Peter S. C. Schulze, Simon Van De Walle, Geert Van Royen, Lisa M. Schüler, Inês B. Maia, et al. "Drying Microalgae Using an Industrial Solar Dryer: A Biomass Quality Assessment." Foods 11, no. 13 (June 24, 2022): 1873. http://dx.doi.org/10.3390/foods11131873.

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Microalgae are considered a promising resource of proteins, lipids, carbohydrates, and other functional biomolecules for food and feed markets. Competitive drying solutions are required to meet future demands for high-quality algal biomass while ensuring proper preservation at reduced costs. Since often used drying methods, such as freeze or spray drying, are energy and time consuming, more sustainable processes remain to be developed. This study tested an indirect and hybrid solar dryer as an alternative to conventional freeze drying of industrially produced Tetraselmis chui and Nannochloropsis oceanica wet paste. The effects of the drying method on biomass quality parameters, including biochemical profiles, functional properties, and microbial safety, were assessed. No significant differences were found between the applied drying technologies for total proteins, carbohydrates, lipids, and fatty acid profiles. On the other hand, some pigments showed significant differences, displaying up to 44.5% higher contents in freeze-dried samples. Minor differences were also registered in the mineral profiles (<10%). Analyses of microbial safety and functional properties of the solar-dried biomass appear adequate for food and feed products. In conclusion, industrial solar drying is a sustainable technology with a high potential to preserve high-quality microalgal biomass for various markets at expected lower costs.

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Journal articles on the topic 'Freeze-drying processes'

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