The present study is designed to evaluate the effect of infrared assisted spouted bed drying (IR-SBD) on the product quality and energy consumption of whole peanut fruits (including peanut kernels and shells). The dehydration of whole peanuts by means of hot-air drying (HD) and infrared drying (ID) were used as the control groups, and the drying characteristics, energy consumption, microstructure, porosity, hardness and fatty acid content were compared. The results showed that, compared to HD and ID, IR-SBD could reduce the drying time by 40% and 33%, respectively, and reduced energy consumption by 66% and 32%, respectively. During the drying process, the structures of both the peanut shells and peanut kernels underwent significant deformation; specifically, the porosity gradually increased gradually. The maximum porosity value was obtained by the samples dried by means of IR-SBD. Under the three drying conditions, the hardness of the peanut shells first decreased and then increased, while the hardness of the peanut kernels showed a trend of first increasing, then decreasing and finally increasing. Compared to the fresh whole peanuts, the IR-SBD dried samples exhibited a 4.07% decrease in fatty acid. This study shows that IR-SBD is a suitable application for the dehydration process of whole peanuts for the purposes of achieving high-efficiency and -quality production in the industrial sector.

Lonicera japonica Thunb

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.

A multiphase microwave drying (MMD) was proposed to produce dried Chinese yam cubes with good quality comparable to freeze-dried products. The effects of different microwave power loading schemes on the conversion point (water phase in samples changes from solid-to-gas to liquid-to-gas) of MMD were assessed, and the macroscopic physical properties and microstructure characteristics of dried yams were investigated. Results showed that with an increase of microwave power, the time required to reach the conversion point was reduced. And the moisture content at the conversion point as affected by microwave power loading schemes had vital influence on sample quality. When it was 0.378 g·g⁻¹, the properties of the yam cubes resembled those of freeze-dried samples in terms of rehydration, texture, and microstructure. Furthermore, a fractal theory-based microstructure characterization can accurately reflect texture characteristics. MMD has the potential to produce high quality products that matched to freeze-dried ones.

Microwave freeze-drying (MFD) is a new freeze-drying technique, which differs from single microwave treatment; it involves simultaneous effects of microwave power, time, and the moisture state applied to the materials. In this study, the effects of MFD under various microwave power densities (0.5, 1.0, and 1.5 W/g) on the drying characteristics of Chinese yam slices and the physicochemical, pasting, and thermal properties as well as the starch digestibility of the flour were investigated using conventional hot air drying (HAD) at 50 °C as a control. Compared to HAD, MFD shortened the drying time up to 14.29~35.71%, with a higher drying efficiency at a high microwave power density (1.5 W/g). MFD yam flours provided benefits over HAD products in terms of color, water/oil absorption capacity, and solubility, exhibiting high hot-paste viscosity but low resistant starch content. The content of total starch and free glucose of the yam flour and its iodine blue value were significantly influenced by the drying method and the MFD process parameters (p < 0.05). MFD processing could disrupt the short-range ordered structure of yam starch. Among the MFD flours, samples dried by MFD at 1.5 W/g presented the highest ratio of peak intensity at 1047 and 1022 cm⁻¹ (R_1047/1022) value, gelatinization enthalpy, and resistant starch content. These results gave a theoretical foundation for the novel freeze-drying method that MFD applied to foods with a high starch content, enabling the production of a product with the desired quality.