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Summary: The current work was carried out to enhance the quality (including product colour, rehydration performance, textural properties, product cracking rate and sensory evaluation) of microwave freeze‐dried prepared taro balls, a popular starch‐based food product, by synergistic addition of guar gum and sodium bicarbonate. The results showed that taro balls with added sodium bicarbonate had the shortest freeze‐drying time (153 min), but the high‐cracking rate (66.67%) was not acceptable to consumers. The addition of guar gum could effectively reduce the cracking rate (17.5%) during freeze‐drying of taro balls, but did not significantly improve sensory evaluation and textural properties. The combination of sodium bicarbonate and guar gum demonstrated satisfactory positive effects in increasing the rehydration rate of freeze‐dried taro balls (53.67%), maintaining the whiteness (WI = 84.52) and reducing the cracking rate (21.67%). Although sodium bicarbonate alone produced the best results in terms of sensory ratings and textural properties, there was no significant difference between the effects of sodium bicarbonate alone and the combination of the two food additives on rehydrated taro balls. Therefore, the combination of sodium bicarbonate and guar gum is an appropriate hybrid strategy for producing high quality freeze‐dried taro balls. [ABSTRACT FROM AUTHOR]

The objective of this paper was to evaluate the effect of spray drying (SD), spray freeze‐drying (SFD), freeze‐drying (FD), and microwave freeze‐drying (MFD) on the characteristics of fish oil (FO) microcapsules. The physicochemical properties, morphology, fatty acid composition, and stability of the microcapsules were analyzed. The encapsulation efficiencies of microcapsules dried by SD, SFD, FD, and MFD were 86.98%, 77.79%, 63.29%, and 57.89%, respectively. SD microcapsules exhibited superior properties in terms of effective loading capacity, color, and flowability. Conversely, SFD microcapsules demonstrated improved solubility. Microencapsulation positively affected the thermal stability of FO, but the content of unsaturated fatty acids decreased. The findings from the storage experiment indicated that the oxidative stability of SD fish oil microcapsules was marginally lower compared to microcapsules produced through three alternative drying techniques, all of which were based on the FD concept. The comparison of various drying methods and their effects on the quality of FO microcapsules offers valuable insights that can serve as a foundation for the industrial production of high‐quality microcapsules. [ABSTRACT FROM AUTHOR]

Lactobacillus plantarum is a kind of probiotic that benefits the host by regulating the gut microbiota, but it is easily damaged when passing through the gastrointestinal tract, hindering its ability to reach the destination and reducing its utilization value. Encapsulation is a promising strategy for solving this problem. In this study, transglutaminase (TGase)-crosslinked gelatin (GE)/sodium hexametaphosphate (SHMP) hydrogels were used to encapsulate L. plantarum. The effects of TGase concentration and drying method on the physiochemical properties of the hydrogels were determined. The results showed that at a TGase concentration of 9 U/gGE, the hardness, chewiness, energy storage modulus, and apparent viscosity of the hydrogel encapsulation system were maximized. This concentration produced more high-energy isopeptide bonds, strengthening the interactions between molecules, forming a more stable three-dimensional network structure. The survival rate under the simulated gastrointestinal conditions and storage stability of L. plantarum were improved at this concentration. The thermal stability of the encapsulation system dried via microwave vacuum freeze drying (MFD) was slightly higher than that when dried via freeze drying (FD). The gel structure was more stable, and the activity of L. plantarum decreased more slowly during the storage period when dried using MFD. This research provides a theoretical basis for the development of encapsulation technology of probiotics. [ABSTRACT FROM AUTHOR]

Advanced ready-to-eat foods, which can be consumed directly or only need simple processed before consumption, refer to the products that processing with cutting-edge food science and technology and have better quality attribute. Cold chain and chemical addition are commonly used options to ensure microbial safety of high moisture advanced ready-to-eat foods. However, this requires freezing/thawing processing at high cost or has undesirable residue. Dehydration treatment has the potential to compensate those shortcomings. This article reviewed the positive effects of dehydration on advanced ready-to-eat foods, current application status of dehydration technologies, novel dehydration related technologies and the pathogenic bacteria control of products. It is observed that dehydration treatment is receiving increasing attention for ready-to-eat foods including space foods, 3 D-printed personalized foods and formula foods for special medical purposes. Recently developed drying technologies such as pulsed spouted microwave freeze-drying and infrared freeze-drying have attracted much interest due to their excellent drying characteristics. Finally, intelligent drying, dehydration-nano-hybridization and dehydration-induced multi-dimensional modification technology are some of the emerging R and D areas in this field. [ABSTRACT FROM AUTHOR]

Therapeutic protein preparations are usually stored in a solid state to reduce the physical and chemical degradation by removing most of the solvent (mostly water) in liquid protein preparations, improving stability and maintaining biological activity. Freeze-drying (FD) is a common method to produce the dehydrated therapeutic protein. However, various induced stresses exist in the processing steps involved in FD, such as freezing process, primary drying, and secondary drying, may cause protein instability. To overcome this problem, two means are often employed: adding stabilizers to protect proteins from physical damage associated with the FD process; optimizing parameter conditions during the FD process to reduce protein degeneration. Therefore, a deep understanding of the protein preparation formula composition and FD process parameters is crucial for the development of stable therapeutic protein products. This study reviewed the stabilization mechanisms of protein during FD, focused on the factors that induce protein instability, and discussed the relationship between protein structure changes and instability, expected to provide references for solving the instability during protein freeze-drying and storage. [ABSTRACT FROM AUTHOR]

To improve the quality of freeze-dried dumplings, a novel hybrid strategy that different cooking methods combined with chitosan coating were applied in the preparation of dumplings. The dumplings, obtained according to the formula, first treated by three different cooking methods (microwave, boiling, and steaming), respectively, and then coated with chitosan with a mass fraction of 1.5%. The dumplings without coating treatment was used as control group. Results showed that, the drying time of steamed dumplings was the shortest (720 min), but its whiteness and rehydration performance were unacceptable to consumers. The whiteness of boiled dumplings was the highest, but its drying time was 90 min longer than that of steamed dumplings. The freeze-dried dumplings pretreated by microwave cooking had the best rehydration performance (rehydration rate, cracking rate of rehydrated dumplings, and rehydration loss rate) and hardness. Chitosan coating treatment of cooked dumplings was been found to have a satisfactory positive effect on inhibiting the cracking rate of freeze-dried dumplings, the cracking rate of rehydrated dumplings and the rehydration loss rate of freeze-dried dumplings. Microwave cooking combined with chitosan coating was considered to be the most suitable hybrid strategy for the production of high-quality freeze-dried dumplings. [ABSTRACT FROM AUTHOR]

Due to the fast pace of life around the globe and the increasing demand for high-quality convenience foods by consumers, instant foods have attracted widespread attention. By adjusting the process and formula, the quality of compound formula foods can be optimized. Drying is a common way. However, conventional drying methods have some shortcomings. Freeze drying can overcome most of them. Foam mat freeze-drying can increase the drying area of materials, and the drying efficiency of it is also higher. For thermal-sensitive materials, it is a suitable drying method. Microwave freeze drying, infrared drying, and others are relatively new processing technologies that are suitable for the production of instant foods. This paper provides an overview of recent developments in processing technologies for the production of compound formula instant foods. [ABSTRACT FROM AUTHOR]

Sodium bicarbonate medium ultrasound pre-treatment can enhance the freeze-drying process of blueberries, but the quality of dried products cannot meet the actual production needs. To yield higher quality products, chitosan coating was applied in blueberry sodium bicarbonate medium ultrasound pre-treatment enhanced freeze-drying process. The improvement effect of different chitosan coating methodologies on the procedure of blueberry freeze-drying, enhanced by ultrasound pre-treatment in sodium bicarbonate medium, was investigated. These include: chitosan solution soaking alone (CH-A), chitosan medium ultrasound treatment (US-CH), first sodium bicarbonate medium ultrasound treatment then chitosan solution soaking (US-NaHCO 3 + CH) and first sodium bicarbonate soaking followed by chitosan medium ultrasound treatment (NaHCO 3 + US-CH). While the treatments that presoaking in sodium bicarbonate solution (NaHCO 3 -A), water medium ultrasound treatment (US-W) and sodium bicarbonate medium ultrasound treatment (US-NaHCO 3) were used as the control groups. Results demonstrated that ultrasound treatment and sodium bicarbonate soaking have positive effect on improving the freeze-drying characteristics of blueberries, while chitosan coating has a negative effect. Chitosan coating has a significant effect on strengthening limit effect of blueberry skin on juice overflow and weakening moisture absorption capacity of dried blueberry. US-NaHCO 3 + CH pretreatment yielded the best results for blueberry freeze-drying. • Dried blueberry quality is significantly improved after chitosan (CH) coating. • Drying efficiency is still maintained in a high level even after coating blueberry with chitosan. • Ultrasound-NaHCO 3 + CH is found to be the best strategy for blueberry freeze-drying. [ABSTRACT FROM AUTHOR]

The acquisition of high quality lyophilized IgY products, characterized by an aesthetically pleasing visage, heightened stability, and a marked preservation of activity, constitutes an indispensable pursuit in augmenting the safety and pragmatic utility of IgY. Within this context, an exploration was undertaken to investigate an innovative modality encompassing microwave freeze-drying (MFD) as a preparatory methodology of IgY. Morphological assessments revealed that both cryogenic freezing and subsequent MFD procedures resulted in aggregation of IgY, with the deleterious influence posed by the MFD phase transcending that of the freezing phase. The composite protective agent comprised of trehalose and mannitol engendered a safeguarding effect on the structural integrity of IgY, thereby attenuating reducing aggregation between IgY during the freeze-drying process. Enzyme-linked immunosorbent assay (ELISA) outcomes demonstrated a discernible correlation between IgY aggregation and a notable reduction in its binding affinity towards the pertinent antigen. Comparative analysis vis-à-vis the control sample delineated that when the trehalose-to-mannitol ratio was upheld at 1:3, a two-fold outcome was achieved: a mitigation of the collapse susceptibility within the final product as well as a deterrence of IgY agglomeration, concomitant with an elevated preservation rate of active antibodies (78.57 %). [ABSTRACT FROM AUTHOR]

In order to improve the drying efficiency while maintaining product quality, pulse-spouted microwave freeze-drying (PS-MFD) was applied to the dehydration process of blueberries. The present study was carried out to establish a strategy for intelligently determine sublimation/desorption drying transition point (TP S-A) and drying endpoint of blueberry during PS-MFD process. Back-propagation artificial neural network (BP-ANN) model was used to establish the relationship between low field nuclear magnetic resonance (LF-NMR) spectrum and moisture content (MC) as well as between near infrared (NIR) spectrum and MC. Then the two models were applied to predict the moisture content of blueberry during PS-MFD process. Model fitting results showed that BP-ANN models based on LF-NMR spectrum and NIR spectrum could accurately predict the moisture content of blueberries. BP-ANN model of LF-NMR-MC couldn't capture the signal of free water during the early stage of PS-MFD (about 90 min), while BP-ANN model of NIR-MC had moisture content output values of blueberries during the whole PS-MFD process. The TP S-A and drying endpoint of blueberry during PS-MFD process could be accurately determined by comparative analysis of PS-MFD blueberry samples moisture content output values obtained from two models. • A novel hybrid drying method was used in blueberries dehydration process. • TP S-A and drying endpoint were intelligently determined. • BP-ANN algorithm was used in model building process. [ABSTRACT FROM AUTHOR]

The present study was carried out to achieve a more efficient dehydration process along with low undesirable quality decrease for cream mushroom soup (CMS) by combining microwave pre-gelatinization (MPG) with infrared freeze-drying (IRFD). Wheat flour was gelatinized using a microwave heating unit for different times, and was used in CMS formulations. Freeze drying (FD) was carried out using conventional as well as IRFD and drying time, energy consumption and product quality characteristics (flavor, viscosity of rehydrate juice; moisture absorption and crystallinity of dried soup solid) of CMS were studied. Compared to FD, IRFD reduced the drying time and energy consumption by 23.81% and 28.43%, respectively. The microwave pre-gelatinization of wheat flour and subsequent use in IRFD, while in comparing with single infrared freeze drying, did not affect drying time and energy consumption; however, it significantly improved the flavor and viscosity of soup upon rehydration, and reduced the tendency to retrogradation. The microwave pre-gelatinization time of 120 s at 8 W/g energy level was found to be the most suitable condition for microwave pre-gelatinization of wheat flour. Undesirable decrease of viscosity in starch containing soup and high energy consumption of traditional freeze-drying limit the large-scale industrial production of freeze-dried starch containing product. Therefore, inhibiting viscosity reduction and reducing production cost are the crucial steps for industrial production of freeze-dried cream mushroom soup. Microwave pre-gelatinization and infrared freeze-drying have made outstanding contributions on improving starch stability and reducing drying energy consumption, respectively, which caters to the preferences of industrial production and can be used in industrial production of freeze-dried instant cream mushroom soup. • Drying for complex food system was studied. • Infrared freeze-drying improved the drying efficiency of creamy mushroom soup. • Microwave pre-gelatinize improved the quality of dried creamy mushroom soup. [ABSTRACT FROM AUTHOR]

Freeze drying (FD) yields the best quality of dried mushrooms but needs long drying time and higher cost. Air drying (AD) gives relatively poor product quality. In order to achieve faster drying along with high product quality, microwave freeze drying (MFD) and atmospheric freeze drying (AFD) were developed to dry mushrooms. By comparison of three sublimation drying processes, it was concluded that FD could lead to the best product quality, but cost the highest energy consumption. AFD mushrooms had the worst quality and longest drying time, but the lowest energy consumption. Compared with FD and AFD, MFD could get relatively acceptable quality and drying efficiency. As a result, MFD can be used to replace traditional FD, and AFD also should be popularized because of its low energy consumption. [ABSTRACT FROM AUTHOR]