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To solve the problem of quality deterioration caused by easy browning in drying of yuba stick, yuba stick made from Jiusan yellow soybean, a specialty of northeast Heilongjiang, was used as the research object. Vacuum freeze drying (VFD) and hot air drying (HAD) were used for dry processing of yuba stick, to obtain the effects of the two drying methods on the quality characteristics, microstructure, and other parameters of yuba stick. The goal was to provide theoretical support for selecting appropriate factory drying methods. The results showed that the effect of the two drying processes on the protein content of yuba stick reached the level of significant difference (P

Objective: Hot air coupled with ultrasound and infrared irradiation were used for the drying of curdlan. The drying mechanism and quality change of curdlan were explored under the multi-physical fields, so as to developing the green drying technology of curdlan. Methods: Forced convective hot air alone, ultrasound-coupled forced convective hot air, infrared irradiation alone, and infrared-coupled forced convective hot air were used to dry curdlan. A mass transfer model considering temeprature change was constructed and the quality of the dried curdlan was comprehensively assessed. Results: Under the studied forced convective hot air drying conditions, it took around 40 min to dry the curdlan, and the required drying time was reduced to 36, 26 and 22 min for ultrasound-coupled hot air drying, infrared irradiation alone drying, and infrared-coupled hot air drying, respectively. The moisture transfer model coupled with the temperature change was able to accurately predict the change of the moisture content throughout drying. Under infrared drying coupled with convective hot air, the range of moisture effective diffusivity inside curdlan was 9.79×10−9 to 9.81×10−9 m2/s, and the surface mass transfer coefficient was 4.69×10−2 kg water/(m2·s), which were higher than those of the other treatment groups, followed by those under infrared irradiation alone drying, ultrasonic-coupled hot air drying, and hot air drying alone. Moreover, the gel strength, glucose content, the distribution of chemical functional groups on surface, crystal structure and thermal stability of curdlan samples dried by different methods were all similar. Conclusion: Taking all these results into consideration, infrared drying was regarded as an efficient method for drying curdlan compared to hot air drying and ultrasound-coupled hot air drying.

In order to explore the effectiveness of the laboratory’s self-developed equipment - horizontal box cage stacked peanut pods room temperature ventilation drying equipment, this study used this equipment to conduct drying experiments on newly harvested peanut pods. The research focused on analyzing the drying rate of peanuts, changes in temperature and humidity within the pile, and energy consumption, and the results were then compared with natural sun drying and similar drying equipment. The research has found that under the same weather conditions (mainly cloudy and rainy weather), the moisture content of peanuts reduced from an initial 43.77% to below 10% within 9 days with a horizontal box cage stacked peanut pods room temperature ventilation drying equipment. The drying rate was 43% higher than that of natural drying. The drying energy efficiency of peanut pods was 2.64×106 J/kg, and the moisture content of the inner and outer layers of the stacked peanut pods decreased uniformly. This study has demonstrated that the horizontal box cage stacked peanut pods drying equipment can be used for the emergency drying of newly harvested peanut pods.

The study undertook a thin-layer hot air-drying experiment on rice, and an orthogonal testing approach was used to explore the drying characteristics under diverse conditions of hot air temperature, humidity, initial moisture content, airflow velocity, and tempering ratio. It compared the applicability of nine different accumulated temperature-nutritional index (protein, fat, starch) mathematical models in the hot air drying process of rice. The results showed that the experimental scheme was designed using Central- Composite design, and the parameter combination was optimized through a regression model to hot air temperature hot air temperature (T) at 38.5 ℃, humidity (RH) at 48.086%, initial moisture content (MC) at 19.82%, airflow velocity (V) at 0.70 m/s, and tempering ratio (TR) at 1.45. The relative error between the experimental results and the optimized results was 3.65%, and the relative error of the accumulated temperature-nutritional quality model was 5.92%. Through mathematical model fitting, it was found that the accumulated temperature-protein content was best fitted by the modified Page II model, while the accumulated temperature-fat content was best fitted by the Thompson equation. The accumulated temperature-amylose content was best fitted by the Midilli equation, and the accumulated temperature- amylopectin content was best fitted by the Weibull II equation. All models were highly significant. The optimized drying process maintained nutritional quality and improved drying efficiency. This study could provide a new approach for in-depth exploration of the mechanism of rice quality changes and lay a foundation for the subsequent development of intelligent control systems.

When simulating drying-rewetting process of grid cells in numerical groundwater modeling using the block-centered finite-difference approach, the models is highly probable to run into non-convergence, which could greatly affect the applicability of groundwater models. This study used ideal case and practical simulation in Denmark to comprehensively compare the simulation capabilities and characteristics of two algorithms, namely the empirical trial (ET) method proposed by MODFLOW and the always active cell (AAC) method proposed by COMUS, in the drying-rewetting simulation. The results show that: (1) For the ET method, the selection of parameter combination has a significant influence on the model convergence and the simulation results. It is compulsory to continuously optimize the parameter to avoid model failures such as non-convergence and large simulation errors when using the ET method, which greatly increases the difficulty of groundwater model application and time cost. (2) The simulation results from the AAC method are more reliable than those from the ET method. Theoretically, the effect of the AAC method is equivalent to the optimal parameter set in the ET method. Therefore, parameter optimization is no longer needed in the AAC method, which can effectively reduce the difficulty of using groundwater models and meanwhile reduce the uncertainty of simulation results. (3) The numerical accuracy of the intercell horizontal hydraulic conductance in the AAC method is consistent with that of the classical harmonic average method, demonstrating that the AAC method can also be used in the simulation without the drying-rewetting process. In summary, the AAC method is more suitable for simulating the drying-rewetting process of groundwater model cells and is expected to be more widely used in groundwater numerical simulation.

To study the effect of different drying methods on volatile components of jasmine tea, headspace solid phase microextraction combined with gas chromatography-mass spectrometry and electronic nose technology were used for quantitative and qualitative analysis of the volatile compounds in jasmine tea dried by four methods, including heat pump drying, hot air drying, microwave drying and vacuum-freeze drying. The results showed that, the top three response values of electronic nose sensors were W1W, W2W and W5S. Under different drying treatments, it can better reflect the differences in volatile substances in jasmine tea. The results of HS-SPME-GC-MS showed that a total of 96 volatile components (alcohol esters, aldehydes, ketones, olefins and other classes) were identified in jasmine tea by four different drying methods. Among these components, the species of olefin compounds were the most with the amount of 37. The total amounts of the volatile components in jasmine tea by freeze-drying were the most abundant with a relative content of 47.382 μg/g, followed by heat pump drying with a relative content of 44.429 μg/g. And the relative contents of olefin and alcohols were higher than other components. The JTF (jasmine tea fragrance) index of jasmine tea was the highest with a amount of 4.766 by heat pump drying. Therefore, HS-SPME-GC-MS combined with electronic nose technology could be used to distinguish the quality of jasmine tea by different drying methods, and would provide theoretical reference for the selection of drying methods in jasmine tea production.

To investigate the processing methods that could improve the quality of Jingning dried apple snacks, the effects of five drying methods (hot air drying, solar drying, vacuum freeze drying, microwave-pressure puffing drying, and heat pump drying) on energy consumption, antioxidant activity, microstructure, and flavor of dried apples were studied. The results showed that compared with the other four drying methods, in terms of energy consumption that vacuum freeze drying had the highest unit energy consumption (69.48±1.69 kW·h/kg), while solar drying had the lowest unit energy consumption (19.60±1.36 kW·h/kg). In terms of hardness and crispness, dried apples that were dried by hot air drying were found to have the highest levels of hardness and lowest levels of crispness, while those that were dried by vacuum freeze drying were found to have the lowest levels of hardness and a higher degree of crispness. In terms of colour difference, vacuum freeze drying had the highest L* value (72.91±0.59) and the ΔE value was closest to the fresh samples (10.48±0.30). In addition, compared with fresh samples, vacuum freeze drying effectively slowed down the loss of antioxidant activity of dried apples, with the contents of ascorbic acid, total phenols and total flavonoids decreased by 35.22%, 39.27% and 32.02%, respectively. Meanwhile, the total antioxidant capacity, hydroxyl radical scavenging rate and superoxide anion scavenging rate decreased by 23.50%, 57.24% and 10.56%, respectively. In terms of microstructure, the cell layer of dried apples with vacuum freeze drying preserved a regular sponge-like porous structure with good texture. In terms of flavor, 96 volatile substances were identified in five types of dried apples, while it made the dried apples with vacuum freeze drying more aromatic and richer in taste. In conclusion, vacuum freeze drying is recommended as a method to improve the quality and flavor of high-quality dried apples, and provides significance in guiding the industrialized production of dried apple products.

To investigate the effects of different microwave drying conditions on the texture and nutritional quality of candied strawberries in a vacuum environment. This study investigated the effects of three different vacuum microwave treatment conditions (2.5 w/g-1.5 h, 3.5 w/g-1 h, 4.5 w/g-0.5 h) on moisture migration characteristics, texture, microstructure, color, anthocyanins, and phenolics of candied strawberries, which were evaluated by hot air drying. The results showed that the time required for vacuum microwave drying to dry candied strawberries to 20%±2% moisture content was significantly lower than that of hot air, and the higher the microwave power, the shorter the drying time. In addition, the water in the candied strawberries obtained after drying mainly appeared in two states, namely, bound water and water not easy to flow. The relaxation time T2 of strawberry candied strawberries obtained by vacuum microwave drying increased with the increase of microwave power, which indicated that the degree of freedom of water increased. Cross-sectional microscopic observation found that vacuum microwave drying caused cell wall rupture, and the higher the microwave power, the closer the site of fissure formation to the medullary core, and the bigger the fissure, and the smaller the porosity, whereas the cellular integrity and the porosity of the samples dried by the hot air were higher than that of microwave drying. In addition, the hardness, viscosity, and a* value of vacuum microwave-dried dried strawberry preserves were lower than those of hot air-dried samples, but the L* value, total sugar, anthocyanin, and phenolic content were higher. In conclusion, vacuum microwave drying had higher drying efficiency and could better retain the nutrients such as anthocyanins in candied strawberries.

To improve the uniformity of microwave heating and enhance the quality of continuous microwave drying for raspberry pulp, a self-developed programmable logic controller (PLC) control system with pulsed microwave output was implemented. The central composite experimental design method was employed to analyze the effects of four experimental factors, namely microwave duty cycle, pulse period, air velocity and drying time on the average temperature, temperature dispersion value, moisture content, moisture content dispersion value, anthocyanin retention rate, and anthocyanin retention rate dispersion value of raspberry pulp. The optimal process for pulsed microwave drying of raspberry pulp was obtained. Compared with dried pulp quality and uniformity indexes from pulsed microwave drying, commonly used feedback temperature control microwave drying, intermittent microwave drying, and continuous microwave drying processes to develop a continuous microwave drying quality optimization control system for raspberry pulp. The results showed that the magnetron from pulsed microwave drying in the form of pulse output rectangular wave form power through the PLC control system. Turning on the magnetron intermittently was more effective than continuous microwave heating. Pulsed microwave drying of raspberry pulp has better product quality and heating efficiency, lower cost and better reliability than feedback temperature control systems. The optimal process parameters for pulsed microwave drying were microwave duty cycle of 0.6, pulse period of 17 seconds, air velocity of 1.9 m/s, and drying time of 12.5 minutes. Compared with continuous microwave drying, pulsed microwave drying resulted in the highest quality of dried pulp as a 35.31%±0.55% increase in anthocyanin retention, a 33.59%±0.23% increase under feedback temperature control, a 16.42%±0.18% increase under intermittent microwave drying. Pulsed microwave drying can control the power to reduce the dried fruit pulp temperature, improve the uniformity of post-drying quality and provide a basis for the industrial production of dried raspberry products.

To explore the effect of different drying methods on the floral quality and volatile flavor compounds of Jinmudan tea flowers, three drying techniques were selected including vacuum freeze-drying (pre-freezing for 2 hours, freeze-dried for 6, 8, 10 hours, cold trap temperature −50 ℃, which were treatments 1, 2 and 3 respectively), hot air drying (the treatment time was 3, 4 and 5 hours, and the baking temperature was 75 ℃, which were treatments 4, 5 and 6 respectively), and natural drying (CK). The effects of these drying processes on sensory quality, chemical composition, amino acid profile, and volatile flavor compounds of tea flowers were analyzed. The results revealed that tea flowers dried using the vacuum freeze-drying method exhibited the best sensory quality, with a distinct honey aroma preserved. Among them, the tea flowers subjected to treatment 3 obtained the highest overall sensory evaluation score, along with higher levels of water extract, tea polyphenols, and caffeine content. Furthermore, they exhibited the highest total amino acid content, sweetness amino acid content, freshness amino acid content, and essential amino acid content. A total of 107 volatile compounds were identified across the 3 drying processes, with alcohols, alkanes, and ketones comprising the predominant volatile components. Hierarchical cluster analysis (HCA) based on principal component analysis (PCA) further classified the volatile substances into 4 groups corresponding to 3 drying methods. A partial least squares discriminant analysis (PLS-DA) model was established to select 35 volatile components with variable importance in projection (VIP) values greater than 1, indicating differential markers. Additionally, the volatile substance patchoulol was identified as unique to the CK group. In summary, vacuum freeze-drying is the most effective method for preserving the aroma and bioactive compounds of tea flowers, with treatment 3 demonstrating the optimal overall evaluation. This study provides a theoretical basis for exploring the effects of drying methods on the quality and flavor of tea flowers and their corresponding changes in volatile components.

The freeze-drying is a technology that preserves biological samples in a dry state, which is beneficial for storage, transportation, and cost saving. In this study, the bovine pericardium was treated with a freeze-drying protectant composed of polyethylene glycol (PEG) and trehalose (Tre), and then freeze-dried. The results demonstrated that the mechanical properties of the pericardium treated with PEG + 10% w/v Tre were superior to those of the pericardium fixed with glutaraldehyde (GA). The wet state water content of the rehydrated pericardium, determined using the Karl Fischer method, was (74.81 ± 1.44)%, which was comparable to that of the GA-fixed pericardium. The dry state water content was significantly reduced to (8.64 ± 1.52)%, indicating effective dehydration during the freeze-drying process. Differential scanning calorimetry (DSC) testing revealed that the thermal shrinkage temperature of the pericardium was (84.96 ± 0.49) ℃, higher than that of the GA-fixed pericardium (83.14 ± 0.11) ℃, indicating greater thermal stability. Fourier transform infrared spectroscopy (FTIR) results showed no damage to the protein structure during freeze-drying. Hematoxylin and eosin (HE) staining demonstrated that the freeze-drying process reduced pore formation, prevented ice crystal growth, and resulted in a tighter arrangement of tissue fibers. The frozen-dried bovine pericardium was subjected to tests for cell viability and hemolysis rate. The results revealed a cell proliferation rate of (77.87 ± 0.49)%, corresponding to a toxicity grade of 1. Additionally, the hemolysis rate was (0.17 ± 0.02)%, which is below the standard of 5%. These findings indicated that the frozen-dried bovine pericardium exhibited satisfactory performance in terms of cytotoxicity and hemolysis, thus meeting the relevant standards. In summary, the performance of the bovine pericardium treated with PEG + 10% w/v Tre and subjected to freeze-drying could meet the required standards.

[Objective] To analyze the differences in volatile components between three kinds of dried L. edoeds. [Methods] Three different drying methods (hot air drying, radio frequency-hot air drying, vacuum freeze drying) were used to determine the volatile substances in L. edoeds by gas chromatogi-ion migration spectrometry (GC-IMS), and the differences of volatile substances in L. edoeds were analyzed according to fingerprint and PCA. [Results] The main volatile components of dried L. edoeds were aldehydes, alcohols, ketones and acids. There were significant differences in the characteristic volatile organic substances of dried L. edoeds in three different drying methods, the contents of aldehyde and alcohol were hot air drying > radio frequency-hot air drying > VD. Fingerprint analysis showed that compared with vacuum freeze drying, hot air drying and radio frequency-hot air drying could significantly improve the fruity flavor of L. edoeds. PCA analysis showed that the contribution rate of PC1 and PC2 was 61% and 29%, respectively, and the cumulative contribution rate reached 90.0%. Hot air drying and radio frequency-hot air drying had high similarity in the flavor composition of L. edoeds. [Conclusion] GC-IMS can realize differential and rapid analysis and identification of volatile flavor components of L. edoeds produced by three drying methods, and provide theoretical reference for high-quality drying of L. edoeds and its product identification.

In order to explore the effects of drying methods on the physicochemical properties and structure of Phyllostachys pubescens shoot powder (PPSP), this research used bamboo shoots as raw materials, and used spray drying (SD), hot air drying (HAD) and low-temperature vacuum drying (LVD) to get 3 kinds of PPSP. The nutrient content, water holding capacity, oil holding capacity, swelling capacity, color, and other physicochemical properties of samples were compared, and their structures were analyzed by infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The results showed that the nutritional characteristics of PPSP prepared by different drying methods were significantly different（PLVD>HAD. The L*, a* and b* value of PPSP in the three groups were significantly different in color. The L* value of LVD sample was 77.32, which was significantly higher than that of SD and HAD samples (P

Flavor is an important characteristic of seafood products, and drying can produce unique pleasant flavors. Drying is among the most common methods for processing seafood products. It can improve quality and shelf-life of seafood products and produce unique flavors. Oxidative hydrolysis of lipids during dry fish processing in the presence of light, photosensitizers, heat, oxygen, transition metal ions, and microorganisms produces volatile small molecules, including alcohols, ketones, aldehydes, and acids, which contribute to the flavor profile of dried fish. Volatile compounds are important components of seafood flavor. Flavor analyses are usually performed using gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) in combination with electronic nose/tongue techniques, which not only characterizes the molecular composition of volatile components in the sample, but also yields macroscopic results via the electronic nose/tongue, ultimately combining instrumental analysis with quantitative sensory data for a comprehensive evaluation of sample flavor. Currently, the market sales model of Cololabis saira is mainly based on a single frozen whole C. saira, and excludes most types of deep-processed products. There is an urgent need to enrich research into processing effects on C. saira quality and flavor, and further develop markets for deep-processed C. saira products. To explore the effects of different drying methods on C. saira flavor, we assessed flavor molecule profiles using GC-MS and electronic tongue techniques. This study aimed to provide a theoretical basis for improving C. saira product flavor, thereby enhancing the economic impact of the C. saira industry. In this study, C. saira was thawed in low-temperature air, and the giblets were removed and diagonally cut. Pre-treated fish were then soaked in 15% salt water for 1 h, drained naturally, and subjected to natural drying (natural air-drying on a sunny day in autumn for 3 days, environmental temperature 10~20 ℃, humidity 25%~42%), cold air-drying (continuous cold air-drying for 3 days, setting temperature (15±2) ℃, relative humidity 38%~40%), and UV with cold air-drying (continuous UV with cold air-drying for 3 days, ultraviolet lamp irradiation, setting temperature (15±2) ℃, relative humidity 38%~40%). The flavor profiles of fresh fish (CK), cured fish (0 d), naturally dried fish (N), cold air-dried fish (C), and UV treated cold air-dried fish (U) were compared. Significant differences were observed in the odor and taste of dried C. saira among products of the different drying methods. GC-MS results showed that a total of 58 volatile flavor substances were detected, including aldehydes, alcohols, ketones, acids, hydrocarbons, and nitrogenous compounds. Increased alcohols, aldehydes, and ketones enriched the fatty aroma of the three dried C. saira samples to varying degrees. Among them, the contents of cis-2-heptenal, octylaldehyde, 2-ethylfuran and other substances in U group increased significantly, increasing to 64.96,569.48 and 189.27 μg/kg, respectively, so that the U group had richer fat flavor. Hexanal, heptanal, Z-4-heptenal, octanal, nonanal, (E, E)-2,4-heptadienal, (E, E)-2,6-nonandialdehyde, 1-octen-3-ol, heptanol, 2,3-pentanedione, 3,5-octadien-2-one, and trimethylamine were the odor-active substances common to the five C. saira samples and were used as flavor compounds to characterize the oily and fishy taste of C. saira. E-2-nonenal, 2-ethylfuran, E-2-octenal, 2-nonanone, 2-undecanone, and 1-nonanol are three odor-active substances specific to dried C. saira, with E-2-octenal, 1-nonanol and 2-undecanone, which have an oily smell, and 2-ethylfuran, which has a burnt smell, having the highest odor aroma-active in the U group. Salty taste, richness, bitterness, astringency, and sourness of the fish increased after the drying process, especially salty taste and richness. Only fresh taste was significantly reduced relative to fresh fish. Saltiness, freshness, and richness of dried fish are important taste indicators. Salty taste and richness increased significantly after the three drying processes, whereas freshness decreased. Group U exhibited the highest salty taste and richness. In conclusion, the volatile odor and profile of C. saira changed significantly with each of three drying processes (natural drying, cold air drying, and UV with cold air drying), all of which increased the fatty flavor and considerably reduced the fishy flavor. Moderate oxidation positively contributes to C. saira flavor. Increased fatty flavor reduces the proportion of fishy substances, thus improving C. saira flavor. UV irradiation with cold air drying promoted lipid oxidation to some extent, producing more fatty substances, as well as cis-2-heptenal and 2-ethylfuran, which enriched the roasted, charred flavor of dried C. saira. Salinity, freshness, and richness are important taste indicators of dried C. saira. All three drying methods enhanced the salinity and richness of C. saira, and UV irradiation with cold air-drying significantly improved the salinity and richness of the fish and enriched its taste and aftertaste. Therefore, among the three drying methods, the method involving UV with cold air drying significantly enriched the flavor of C. saira to the greatest extent.

In this study, the effects of different drying methods on the polyphenol content and antioxidant activity of noni fruit were compared. The total phenol content and the content of seven phenolic compounds in noni samples after natural sun-drying, vacuum freeze-drying, and hot-air drying were determined using the forint-phenol colorimetric method and high-performance liquid chromatography (HPLC). The antioxidant capacity of each sample was assessed using the free radical scavenging ability and iron ion reducing ability experiment. The results showed that the total phenolic content of noni fruit after natural sun-drying, vacuum freeze-drying and hot air-drying were 7.78, 12.42 and 6.38 mg/g, respectively. The scavenging ability against DPPH radicals were 17.57, 35.98 and 13.63 μmol Trolox/g, and the scavenging ability against ABTS+· were 17.57, 36.09, 13.63 μmol Trolox/g. The FRAP antioxidant values were 43.12, 73.49, 39.12 μmol Trolox/g, respectively. There was no significant difference (P>0.05) in total polyphenol content and antioxidant properties between the noni fruits after naturally sun-drying and hot air-drying. However, these properties were significantly different (P

In order to reduce the loss of diagnostic components of peppermint granule spices during the drying process, the moisture drying kinetics of peppermint granules under different drying conditions (oven drying, microwave vacuum drying and microwave drying) were studied. By investigating changes in moisture distribution and the volatilization of characteristic components, the authors determined the optional drying conditions for the spices. The flavoring effect of cigarette filter rod of peppermint granular spices was investigated. The results showed that the drying time of peppermint granular spices under oven drying, microwave vacuum drying and microwave drying was about 60~120 min, 20 min and 4 min, respectively. The optimal drying kinetic model of the three drying methods is the Page model. The results of LF-NMR analysis showed that with the progress of drying, the semi-bound water was transformed into bound water and free water. At the same time, free water is constantly evaporating and being removed. The concentrations of diagnostic components in peppermint granular spices decreased with the decrease of moisture content, and the higher the drying temperature, the more obvious the diagnostic components loss. The effect of microwave drying is better than microwave vacuum drying, and the drying time is greatly shortened. The residue of diagnostic components positively correlated with the peak area of the bound water. The acids and phenolic substances in the cigarette smoke after the spice of peppermint granular spices were slightly reduced, the ketones were slightly increased, and three kinds of diagnostic components unique to peppermint, menthol, L-menthol and menthone were added, which could bring a cooling feeling to the cigarette, reduce the sense of irritation and improve the smoking quality of cigarettes, while retaining the original style of cigarettes. [ABSTRACT FROM AUTHOR]

This study analyzed and compared the effects of different drying methods on the volatile composition and aroma characteristics of Osmanthus fragrans extract and absolute oil. The volatile composition was determined by gas chromatography-mass spectrometry (GC-MS) and partial least squares-discriminant analysis (PLS-DA), relative odor activity value (ROAV), aroma profile radar and principal component analysis (PCA) were employed to determine the effect of different drying methods on the volatile aroma components of O. fragrans extract and absolute oil. The results showed that a total of 113 volatile components were identified. The types and concentrations of volatile components were significantly different among samples (P < 0.05). Through PLS-DA analysis, 36 volatile marker substances were selected using the cut-off of variable importance in the projection (VIP) score greater than 1, and the accuracy of predictive discrimination of O. fragrans extract and absolute oil prepared by different drying methods was 99.6%. The ROAV and aroma radar plots showed that dihydro-β-ionone, linalool, nonanal, β-ionone, and dihydro-β-iononeone contributed significantly to the aroma of O. fragrans extract and absolute oil, being responsible for the floral, woody, and fruity aromas. Notably, the extract from freeze-dried O. fragrans exhibited a more intense aroma. PCA analysis indicated that freeze-drying contributed to improving the aroma quality of O. fragrans extract and absolute oil. The results of this study provide theoretical support for process optimization and quality improvement of O. fragrans extract products.

In order to investigate and evaluate the processibility of broccoli by-products (stems and leaves) and hence to provide a reference for their rational utilization, this study investigated the physicochemical properties and nutritional quality of broccoli stem and leaf powders prepared by different drying methods, namely vacuum freeze drying (FD), microwave freeze drying (MFD), heat pump drying (HPD) and hot air drying (HAD). The results showed that the color difference ΔE between MFD-treated and fresh broccoli stems was 8.52 ± 0.02, which was smaller than that between HAD-treated and fresh samples (30.27 ± 0.28), indicating that MFD had better color preservation effect. The median particle size ranges of broccoli stem and leaf powders were 31.19–52.09 and 32.30–40.47 μm, respectively. Broccoli leaf powder had lower water and oil retention capacities but higher swelling force than that broccoli stem powder. The water retention capacity of FD-dried broccoli stem powder was (11.40 ± 0.46) g/g, and the oil retention capacity of MFD-dried broccoli stem powder was (1.40 ± 0.04) g/g. FD and MFD could effectively maintain the microstructure of broccoli stems and leaves, with obvious pores. The specific energy consumption of FD and MFD for treating an equal amount of broccoli stems was 7.35 and 3.26 kW·h/kg, respectively, so MFD reduced energy consumption by 55.65% when compared with FD. MFD maintained heat-sensitive and readily oxidized nutrients well, resulting in good antioxidant activity. The 1, 1-diphenyl-2-picryl hydrazine (DPPH) scavenging capacity, 2, 2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) cationic radical scavenging capacity and ferric ion reducing antioxidant power (FRAP) of MFD broccoli leaf extract at a concentration of 0.125 mg/100 mL were 70.21%, 71.11% and (0.31 ± 0.01) mmol/g, respectively. In summary, broccoli stem and leaf powders had good physicochemical properties and nutritional quality and therefore could be used as raw materials for developing functional foods. The application of drying technology enables the rational utilization of broccoli stems and leaves.

To explore the moisture variation law of high oleic peanuts during hot air drying, hot air drying characteristics of various high oleic peanuts under different hot air temperatures (35, 40, 45, 50 ℃) and hot air velocities (0.5, 0.8, 1.1 m/s) were studied in this paper, and their drying processes were analyzed by Weibull distribution function. The results showed that the drying process of high oleic peanuts mainly reduced the rate of drying. Increasing hot air temperature and hot air velocity led to a higher effective moisture diffusion coefficient for high oleic peanuts. In turn, accelerates drying rate and shortens drying time. Among all the peanuts, 'Shengyou 3' peanut had the fastest water diffusion rate and lowest activation energy, and the Weibull distribution function provided the most suitable fit for 'Shengyou 3'. The scale parameter α decreased as hot air temperature and hot air velocity increase. Hot air temperature had a highly significant effect on α (P

In order to improve the drying quality of rice, Indica and japonica hybrid rice were taken as the object and evaluated by waist burst rate, head rice rate, energy consumption and drying time in this experiment. Single factor and response surface analysis were combined to optimize the drying process. The effects of variable temperature-tempering drying on proteins structure and thermal properties of indica and japonica hybrid rice were investigated by differential scanning calorimetry. Fourier infrared spectroscopy and fluorescence spectroscopy. The results showed variable temperature-tempering drying (temperature range 30~60 ℃) that under the conditions of temperature rise 5 ℃, wind speed 1 m/s and tempering ratio 0.6, the rice could be kept in the glassy state, and the waistband burst rate and head rice rate after drying were 79.89% lower and 39.54% higher than those in the constant temperature group (60 ℃), respectively. Under these conditions, the polarity of rice proteins decreased and intermolecular aggregation occured, which improved the thermal stability of rice proteins, and the α-helix content increased from 16.21% to 17.64%. Scanning electron microscope results showed that the surface structure of protein was not significantly affected by variable temperature-tempering drying. The experiment explored and verified the drying mechanism of hybrid rice with variable temperature-tempering drying, which would provide a theoretical and practical reference for the research of high quality drying of hybrid rice.

This study aimed to understand the flavor and taste characteristics of dried Boletus edulis products prepared by different drying methods and to explored the difference in flavor among the dried products. The volatile flavor substances and non-volatile taste substances of B. edulis dried by three different drying methods including hot air drying (HAD), vacuum freeze drying (VFD) and vacuum drying (VD) were measured and analyzed. Totally 64 and 85 volatile organic compounds (VOCs) were identified by gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS), respectively. The fingerprint analysis results showed large differences among the dried products, the most significant differential characteristics being found in the VD dried product. Orthogonal partial least squares-discriminate analysis (OPLS-DA) selected 17 and 22 differential characteristic markers based on the results of GC-IMS and GC-MS, respectively. Relative odor activity value (OAV) analysis showed that the key VOC was 1-octen-3-ol. The analysis of non-volatile taste substances indicated that the highest contents of both free amino acids (FAAs) and 5’-nucleotides were found in the HAD-dried product, which were 234.57 and 27.870 mg/g, respectively. Among the 16 free amino acids (FAAs), glutamic acid was the major contributor to umami taste. In summary, HAD is more conducive to the accumulation of taste substances in B. edulis, while VD results in a higher number and amount of flavor compounds. This study could provide a reference for the selection of a method for the postharvest drying of fresh B. edulis.

Investigating the moisture migration during the wood drying process can help improve wood utilization. Single-sided nuclear magnetic resonance (NMR) technology facilitates such investigation with its advantage in conducting one-dimensional measurements along different directions of wood, allowing for the detection of moisture transfer at different depths along the axial and transverse directions during the wood drying process. This research focused on Pinus sylvestris var.mongolica wood, on which a glue sealing technique was employed to ensure that the moisture only transfers along the axial or transverse axis, and the apparent transverse relaxation time (T2app) was utilized to delve into the changes of moisture content at various depths during the drying process. The results showed that at the first 2 hours of the drying process, there was a little free water near the evaporation surface of Pinus sylvestris var.mongolica wood, followed by a scarcity of free water during the drying process, and a noticeable moisture content gradient was observed near the evaporation surface. When the moisture transferred along the axial direction, the farther the moisture was away from the evaporation surface, the more uniform the moisture distribution was. When the moisture transferred along the tangential direction, the farther the moisture was away from the evaporation surface, the more obvious the moisture difference in each layer was. By single-sided NMR technology, it is possible to ascertain the moisture content of wood at various depths, thereby offering a theoretical framework for revealing the migration mechanism of water within wood.

To investigate the effect of drying methods on the volatile flavor substances of Toona sinensis, the volatile components of vacuum freeze-dried, heat pump-dried, hot air-dried, and microwave vacuum-dried Toona sinensis samples were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS) and gas chromatography-mass spectrometry (GC-MS) coupled with relative odor activity values, and the differences of volatile components among samples were further explored by combining the stoichiometric principal component analysis and partial least square discriminant analysis. The results showed that 78 peaks were detected and 59 compounds were identified by GC-IMS. 94 kinds of volatile compounds were identified by GC-MS, and the main volatile components were sulfides, olefins and aldehydes. The content of total volatile compounds was significantly reduced after drying. The key aroma compounds in Toona sinensis samples were identified by ROAV method, such as (E,Z)-di-1-propenyldisulfide, 2-mercapto-3,4-dimethyl-2,3-dihydrothiophene, hexanal, 2-hexenal and eugenol. The PCA and PLS-DA results showed that the samples with different drying methods were not only clearly separated from the raw samples, but also significantly different from each other. The raw samples and vacuum freeze-dried samples were grouped, and the other three dried Toona sinensis samples were grouped. According to the variable importance in projection score, a total of 10 (VIP>1) labeled volatile compounds were selected. The drying method had significant effect on the flavor characteristics of Toona sinensis, and the vacuum freeze-dried group was the closest to the raw sample, while heat pump-drying was the most suitable dehydration method for Toona sinensis, considering the practical application. This study provides some theoretical references for flavor quality control in the thermal processing process.

This purpose of this study was to evaluate the effect of pre-drying on the oil penetration and texture characteristics of deep-fried battered and breaded fish nuggets. Battered breaded fish nuggets (BBFNs) were dried in a drying oven and dried at 40 ℃ for 3, 4.5, 6, 7.5 and 9 h and deep fried at 180 ℃ for 60 s. Moisture state in dried BBFNs and deep-fried BBFNs was measured, and the oil content and distribution, microstructure and texture characteristics of deep-fried BBFNs were analyzed. The absorption of oil during deep-fat frying was simulated. The results showed that after deep-fat frying, the contents of strongly bound water (T21), weakly bound water (T22) and free water (T23) in the crust, the content of strongly bound water in the fish nuggets, the content of weakly bound water inside muscle fibers, and the content of free content outside muscle fibers were reduced. As the drying time increased, the starting time of peak T22 for the deep-fried crust gradually decreased, indicating declined freedom degree of water, and the signal intensity of peaks T21 and T22 decreased, suggesting that the bound water was converted to free water. In addition, only fish nuggets with 9 h drying showed a left shift in peak T22. The surface oil (SO) and total oil (TO) contents of deep-fried BBFNs decreased while the penetrated surface oil (PSO) content increased. The crust structure was first tight and then became rough, and the surface of the fish was smooth first and then exhibited cracks and holes. The fluorescence intensity of the crust became weaker gradually. The Sudan red-dyed region in the crust decreased while that of the junction between the crust and the fish nuggets increased gradually. The hardness and crispiness of the crust first decreased and then increased, while the elasticity and chewiness of the fish nuggets presented the opposite trend. These results indicated that pre-drying alleviated the freedom degree of moisture in BBFNs, and changed the microscopic structure of deep-fried BBFNs, thereby affecting the oil penetration and texture characteristics. The study may provide a theoretical basis and scientific guidance for the large-scale production of low-fat deep-fried BBFNs.

To study the effects of hot air temperature and slice thickness on the drying characteristics, physicochemical properties and antioxidant components of Mulusasiatica Nakai slices. The Mulusasiatica Nakai slices with thickness of 3 mm and 5 mm were dried in the hot air temperature range of 60, 70, 80, 90 ℃. Five classical food thin layer drying models were used to nonlinear fit the experimental data, and the diffusion coefficient and activation energy were calculated. The color, hardness, rehydration properties and antioxidant components of the dried slices were analyzed. Results showed that, the drying time was obviously shortened with the increase of hot-air temperature and the decrease of slice thickness. In the experimental drying temperature range, the effective diffusion coefficient increased with the increase of temperature. The activation energies were 17.46 kJ/mol and 23.82 kJ/mol when the slice thickness was 3 and 5 mm, respectively. Fick diffusion model was used to describe the evaporation process of Mulusasiatica Nakai slices. Compared with other models, Page model could better fit the drying process of Mulusasiatica Nakai slices. When the slice thickness was 3 mm and the hot-air temperature was 90 ℃, the dried product was light yellow, with high rehydration performance and low hardness. In terms of antioxidant retention, heat lost about 50% of ascorbic acid, but only about 35% of total phenolics. In conclusion, the slice thickness could be selected to be 3mm, the hot air temperature 90 ℃ for drying, drying time 90 min, dried product color was light yellow, higher rehydration performance, lower hardness, and could better retain the antioxidant components in Mulusasiatica Nakai.

To investigate the effects of different drying methods on the rehydration and quality characteristic of low salt pickled abalone, this study used vacuum freeze drying, cold air drying and hot air drying to dry them. The mass volume and rehydration rate of the rehydration process were studied. Low field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) were used to study the water distribution during the rehydration process and investigated the changes in the samples of color, texture, tissue morphology and free amino acids after rehydration. The results showed that the rehydration rate of vacuum freeze-dried abalone was 278.73% at 72 hours, which was significantly higher than that of cold-air dried abalone and hot-air dried abalone (P

Spray drying technology is one of the most commonly used unit operations in the production of traditional Chinese medicine(TCM) preparations, offering advantages such as short drying time and uniform product quality. However, due to the properties of TCM extracts, such as high viscosity, strong hygroscopicity, and poor flowability, there is limited scope to solve the problems of wall adhesion and clumping in spray drying from the macroscopic perspective of pharmaceutical production. Therefore, it has become a trend to study and optimize the spray drying process from the microscopic point of view by investigating single droplet evaporation behavior. Based on the reaction engineering approach(REA), the single droplet drying system, as a novel method for studying droplets, collects parameter data on individual TCM droplets during the drying process and uses the REA to process the data and establish predictive models. This approach is crucial for understanding the mechanism of TCM spray drying. This paper summarized and analyzed the cha-racteristics of various single droplet systems, the application of REA in single droplet drying systems, and its significance in optimizing the process, predicting drying states, and shortening the development cycle in the field of TCM spray drying, and looked ahead to the prospects of this method, including the introduction of new parameters and imaging techniques, aiming to provide a reference for further research in the field of TCM spray drying.

Coal gangue, which accumulates in the open air, is modified by immersion in rain, and exhibits different tendencies to spontaneous combustion in different areas of precipitation. To study the role and influence of moisture on the oxidation and spontaneous combustion of coal gangue, we used high-sulfur coal gangue prone to spontaneous combustion in the Qipanjing area of Inner Mongolia. First, the coal gangue is soaked with different moisture content (moisture content: 0, 15%, 30%, 50%, 100%). After soaking for 45 days, the coal gangue is naturally air dried. The dried gangue samples were put into the self-made programmed temperature experiment furnace to conduct experiments on the pre-treated coal gangue samples (the temperature rise rate was set at 3℃/min, and the temperature rise range was set at 30−390 ℃). The gas the temperature points of the coal gangue in each stage was collected by air collecting bag (each rise of 15 ℃ was a stage). Finally, the collected gas was passed into the GC-4000A gas chromatograph. By comparing the O2 consumption、the volume fraction of CO, CH4, C2H4, C2H6 and other index gases produced by coal gangue treated with different moisture content, the results show that: The low temperature oxidation of coal gangue is the best when the moisture content is 15%, the initial formation temperature of CO, CH4, C2H4, C2H6 and other indicator gases is the lowest, and the concentration of various indicator gases is the highest when the temperature is 390℃. When the moisture content exceeds 50%, under the action of moisture dissolution, a large number of combustible substances in the coal gangue are carried and dispersed by moisture, resulting in a significant decrease in the concentration of various indicator gases generated when the moisture content of the coal gangue rises to 390 ℃, even lower than that of the control experimental group without moisture immersion and redrying treatment. When the coal gangue is immersed in water, the initial temperature points of the various index gases are reduced by about 15 ℃.

Objective: This study aimed to explore suitable drying methods for oil tea powder, making it easier for oil tea consumption and storage. Methods: Spray drying, vacuum freeze drying and vacuum drying were used to dry oil tea soup, and the quality (moisture content, sensory evaluation and color) and volatile substances of dried oil tea powder were evaluated. Results: The sensory score of vacuum freeze-drying oil tea powder was the highest (93), the water content was the lowest (3.78%), and the color was better（ΔE value 49.74). 104 volatile substances were identified from three drying methods of oil tea powder using SPME-GC-MS technology, of which 14 affected the flavor of oil tea powder. The characteristic flavor substances (nonanal, decanal, (Z)-2-decanal, (Z)-2-nonenal, (E) -3,7-dimethyl-2,6-octadienal) of freeze-drying present green fragrance and fat fragrance. The special aromas of spray drying and vacuum drying are (Z)-3,7-dimethyl-2,6-octadienal, (E)-3,7-dimethyl-2,6-octadienal and decanal, presenting green fragrance, fruit fragrance, and wax fragrance. PCA and comprehensive evaluation indicate that vacuum freeze-drying has the best flavor quality, which is consistent with sensory evaluation results. Conclusion: The flavor quality of vacuum freeze-drying was the best.

In order to explore the effects of different drying methods on the properties of sour cassava starch (SCS), which were processed from cassava starch by lactobacillus fermentation, and then dried under five drying methods including hot air drying (HA), heat pump drying (HP), vacuum freeze drying (VF), spray drying (SD) and sun-drying (S). The properties of SCS were determined, and the comprehensive score was evaluated by coefficient of variation method. The results showed that the SCS processed by HA, with the highest span value of 2.36, had the lowest clarity, blue number and oil retention of 21.57%, 8.96 and 1.74 g/g, respectively. The SCS dried by HP had the lowest specific area of 351.83 m2/kg, had the highest bulk density, water separation and retrogradation of 0.87 g/m, 33.02% and 74.89%, respectively. The product dried by VF, with the lowest bulk density, repose angle and water separation of 0.73 g/mL, 37.49° and 4.64%, respectively, with the highest clarity. Blue number and water-holding ability of 27.03%, 19.64 and 1.43 g/g, respectively, as well as the highest solubility. The SCS processed by SD had the highest specific area, repose angle and oil retention of 407.43 m2/kg, 54.11° and 2.33 g/g, respectively. However, it had the lowest retrogradation of 67.00%. The SCS dried by S, with the lowest span value and water-holding ability of 1.73 and 1.08 g/g. Comprehensive score results indicated that the SCS dried by VF, SD, S, HA and HP, with the comprehensive score of 0.60, 0.38, 0.18, −0.50 and −0.64, respectively. In summary, the best properties of SCS products could be obtained by VF, followed by SD, and then by S, HA and HP were the worst.

In order to investigate the changes in volatile compounds of Morchella esculenta during drying treatments, the volatile compounds of fresh, vaccum freezed-dried, and hot air-dried Morchella esculenta from two different parts (the pileus and stipe) were compared and analyzed by electronic nose combined with headspace gas chromatography-ion mobility spectroscopy (HS-GC-IMS) techniques. The principal component analysis (PCA) of electronic nose data showed that the drying treatment significantly changed the volatile profiles of Morchella esculenta regardless of the sampling parts. The HS-GC-IMS analysis yielded a total of 41 volatile flavor compounds, and abundant amounts of alcohols (40.02%~50.76%), esters (15.82%~25.66%), and aldehydes (18.24%~20.33%) were observed for the fresh sample. Furthermore, the drying treatments resulted in the reduction of alcohols and esters in fresh Morchella esculenta, specifically by 27.39% to 33.51% and 62.14% to 68.51% respectively, while the total contents of ketones and pyrazines increased significantly (P

Grain drying equipment is an important equipment in Chinese agricultural production process, which can significantly improve the quality of grain processing after harvest and reduce the loss rate of mildew and germination during grain storage. At present, the mechanical drying rate of grain in China was only about 30%, and its overall penetration rate still had a great opportunity to improve. The market for grain dryers has great potential for development, and under the encouragement of national policies, the research on the technology, technology and applicability of dryers has been also constantly improved. In recent years, most research on grain drying has focused on process optimization, while there has been less research on grain drying equipment, which has made it difficult to apply excellent process technology and restricted the progress of grain drying equipment. This paper summarized the latest large and medium-sized grain drying equipment and the existing main problems, and put forward some suggestions, which could provide a reference for the research and development of grain drying technology and equipment.

In order to determine the optimal method for drying Apostichopus japonicus gonads, the effects of four drying methods, namely, hot air drying, cold air drying, microwave drying and vacuum freezing drying, on the lipid composition, lipid stability and fatty acid nutritional value of A. japonicus gonads were analyzed and compared. The results showed that the contents of total lipids, phospholipids, triglycerides and astaxanthin reduced to different degrees after drying treatments. The peroxide value (POV) significantly reduced, and the thiobarbituric acid reactive substances (TBARS) value significantly increased (P < 0.05). In terms of fatty acid nutritional values, the atherogenic and thrombogenic indices decreased to different degrees after drying treatments, and the hypocholesterolemic/hypercholesterolemic indices increased significantly (P < 0.05). The results of electronic nose analysis showed significant differences in odor characteristics among dried samples obtained using different drying methods. Gas chromatography-ion mobility spectrometry (GC-IMS) identified 28 volatile substances from fresh and dried samples, among which, 2,5-dimethyl pyrazine was detected only in microwave-dried samples, while pentanal and ethyl acetate were odor-active substances unique to cold air-dried samples. In conclusion, vacuum freeze drying effectively slowed down the rate of lipid oxidation, but the samples were relatively bland in odor. Hot air, cold air and microwave drying all promoted lipid oxidation, but improved the nutritional value of fatty acids and enriched the odor characteristics of the samples. The results of this study could provide a theoretical basis for the processing and utilization of A. japonicus gonads.

Objective: To study the content and quality characteristics of three types of apple pectin (WSP, NSP, CSP) treated by different drying methods. Methods: Apple pectin was dried by hot air drying (60, 75, 90 ℃), vacuum freeze dryingn (−50 ℃) and natural drying. The effects of different drying methods on the browning degree of apple and the pectin content, protein content, total sugar content, antioxidant capacity and pectin structure of three types of apples were studied. Results: The browning degree of apple slices was the smallest under hot air drying at 60 ℃. The content of three different types of pectin was different. The content of WSP was the most, ranging from 58.06% to 77.09%, followed by NSP, ranging from 30.57% to 54.98%, and the content of CSP was the least, ranging from 14.64% to 27.06%. Among them, the content of three types of pectin after hot air drying at 60 ℃ was the most. The total sugar content of WSP, CSP and NSP was 34.56%~6.92%, 11.02%~4.04% and 15.46%~8.75%, respectively. The total sugar content of WSP dried at 75 ℃ was the highest. The total sugar content of NSP and CSP under hot air drying at 90 ℃ was also the highest. The protein content of three different types of pectin was different. The range of WSP, NSP and CSP was 2.92%~5.73%, 1.39%~4.27% and 1.50%~5.40%, respectively. Fourier transform infrared spectroscopy analysis showed that there was little difference in the structure of apple pectin under different drying conditions. The drying method had a significant effect on the antioxidant capacity of pectin. The antioxidant capacity of WSP and NSP ranged from 91.27% to 78.54% and 8.15% to 2.14%, respectively. The antioxidant capacity of CSP was very weak. Among them, the antioxidant capacity of WSP and NSP under 90 ℃ hot air drying was the strongest, which was 91.27% and 8.15%, respectively. The antioxidant capacity of WSP and NSP under freeze drying was the weakest, which was 78.54% and 2.14%, respectively. Conclusion: After apples were treated by different drying methods, the contents and properties of three different types of pectin in apples were different. The apple pectin dried at 60 ℃ was the best, and the apple pectin content, total sugar content, protein content and antioxidant capacity were 50.69%, 15.27%, 3.61% and 31.33%, respectively. This study would provide theoretical support for the extraction process of apple pectin and the antioxidant capacity of different types of pectin, and also provide some reference value for further study on the effect of different drying methods on pectin drying.

Objective: This study aims to investigate the effect of different drying methods on the drying characteristics and volatile flavor of Stropharia rugosoannulata as raw material. Methods： The fresh S.rugosoannulata was dried by freeze-drying, heat pump drying, hot air drying, and microwave drying, and then the physical and chemical indexes were investigated. Results: The contents of crude protein, crude fat, ash, potassium, calcium, total flavonoids, essential amino acids, flavor amino acids and total amino acids are the highest in freeze drying. The six teenamino acids achieved 16.88 g/100 g in the freeze-drying. The rehydration rate and color all play the best performance in freeze drying. The scavenging rate of DPPH radical of S. rugosoannulata polysaccharide reached 61.14% in hot air drying; The rate was hot air drying>heat pump drying>microwave drying>freeze drying. Similarly, the scavenging rate of ABTS radical reached 67.97% in heat pump drying; The rates were heat pump drying>hot air drying>microwave drying>freeze drying. The monosaccharide of S. rugosoannulata is mainly composed of glucose Glc and Galactose gal, among which the content of freeze-dried glucose Glc is the most, accounting for 36.79% of the total sugar; The maximum molecular weight of S.rugosoannulata was freeze-drying; The volatile flavor of S.rugosoannulata different under different drying methods, and the volatile flavor of S. rugosoannulata after drying is quite different from that of fresh S. rugosoannulata. The volatile components in freeze-dried S. rugosoannulata are the most abundant, and some components are high. Conclusion: Freeze-drying has advantages over other drying methods in terms of nutritional composition, rehydration rate, color, and flavor. It has the least impact on the quality of S. rugosoannulata and is the most suitable drying method.

Drying is one of the major methods to extend the shelf life of fruits and vegetables. With the development of computer technology, computational fluid dynamics has been more and more widely used in the field of fruit and vegetable drying. This technique can simulate and predict the kinetic phenomena such as fluid flow, heat and mass transfer during the drying process of fruits and vegetables, and output the visualization results. Compared with traditional experiments, computational fluid dynamics has the advantages of energy saving, low cost, fast simulation speed and high flexibility. This article elaborates on the working principle of computational fluid dynamics in the field of fruit and vegetable drying, and reviews recent progress in the application of computational fluid dynamics to different fruit and vegetable drying methods as well as in the numerical modeling of coupled shrinkage. Finally, this review concludes with an outlook on future directions of computational fluid dynamics in the field of fruit and vegetable drying. It is our hope that this review will provide new insights and references for researchers.

Objective: In order to predict and control the hot air drying process of Mango. Methods: Using fresh Mangifera indica Linn as experimental material, the effects were studied in different hot air temperatures (60, 65, 70 ℃) and different thickness of Mango slices (0.8, 1.0, 1.2 cm) on the drying curve, drying characteristic curve and effective moisture diffusion coefficient of Mango. Selecting six commonly used drying models suitable for fruits and vegetables for fitting, analysis, and validation, the most suitable model for Mango hot air drying was selected. Results: With the increase of temperature and the decrease of slice thickness, the drying rate of Mango slices was accelerated, resulting in shorter drying times. The effective diffusion coefficient of water increases with the increase of temperature and thickness, in the range of 1.401 39×10-10 to 3.655 46×10-10 m2/s. R2 of Logarithmic model was the largest, and X2 and RMSE were the smallest, which were 0.998 87, 0.000 124 779 and 0.001 37 respectively. Conclusion: The predicted values are basically consistent with the experimental values, accord with Mango hot air drying, it can better reflect the changing law of moisture content of Mango slices during drying.

Objective: In order to improve the mushroom drying efficiency and reduce the power consumption, a new type of co-heating and dehumidification drying machine was designed and built. Methods: The drying machine was a closed system, which took the semiconductor refrigeration piece as the main component, with its hot end as heat source for air pre-heating and its cold end as the cold source for water vapor condensation. On the device, the mushroom drying rate at different drying temperatures （55 and 65 ℃） and sample mass （200 and 400 g） were tested. Results: Nine thin layer mathematical drying models were used to simulate the drying rate, which revealed that the Midilli model had a better predict effect than the others. In addition, it was found that the higher drying temperature resulted in a greater color change and a higher shrinkage rate. The comprehensive energy efficiency ratio of the drying machine was 1.96, and the power consumption of drying mushroom was 81.21 MJ/kg. Conclusion: In the experiment, the indexes such as moisture content and color change of dried mushroom met the national standards, and the energy-saving effect was remarkable compared with the traditional electric heating drying machine.

To investigate the impact of variety, slice thickness, and drying temperature on the quality of dried kiwifruit under hot air drying conditions, three different kiwifruit varieties with slice thicknesses of 8, 10, and 12 mm were selected as research subjects. The dried kiwifruit was dried at hot air drying temperatures of 60, 65, and 70 ℃, and texture profile analysis (TPA) and sensory evaluation were conducted on the dried fruit. The results showed that there were significant differences in hardness, springiness and chewiness of all dried fruits when temperature was varied (P0.05). The adhesiveness, springiness, and resilience of the green heart samples could be used to replace the sensory evaluation, while the hardness, springiness, and chewiness of the yellow heart samples could be used to replace the sensory evaluation. Red heart samples still need further research. In conclusion, indices that play a decisive role in the evaluation of the quality of dried kiwifruit are hardness, chewiness, and gumminess, and the correlation analysis of the index of the parameters of dried kiwifruit of different species are significantly different.

The survival rate and storage period of lactic acid bacteria (LAB) are affected by numerous factors in the vacuum freeze-drying process. Hence, optimizing the freeze-drying process and storage conditions is an effective method to improve the survival rate and prolong the storage period of LAB. This paper reviews the factors that influence the survival rate of LAB during the vacuum freeze-drying process and explores how to optimize the freeze-drying process and storage conditions to improve the survival rate and extend the storage period of LAB. We expect that this review will provide a basis and reference for the preparation of lyophilized LAB formulations with high activity and good storage stability.

Objective: This study aimed to investigate the effects of drying methods on passion fruit peels. Methods: Passion fruit peels were treated with microwave vacuum freeze-drying, vacuum freeze-drying, heat pump drying, and far-infrared radiation drying. The drying characteristics, rehydration ratio, color difference, dietary fiber, functional properties, microstructure, total phenolic content, total flavonoid content, and antioxidant properties were measured and determined respectively. Results: Heat pump-dried passion fruit peels had poor rehydration ratio and functional properties. Microwave vacuum freeze drying reduced the drying time by 53% when compared tp far-infrared radiation drying, and the microwave vacuum freeze-dried treated passion fruit peels had a higher rehydration ratio (7.45), total phenolic content (13.45 mg GAE/g DW) and antioxidant activity (DPPH was 38.53%, FRAP was 1.14 mmol/L). Additionally, the passion fruit peels were vacuum freeze-dried with treatment to increase their water holding capacity [(21.64±0.21) g/g], oil holding capacity [(6.09±0.71) g/g], swelling [(25.00±1.00) g/g], and total flavonoid content (7.84 mg RT/g DW). Different drying techniques led to higher rehydration ratios, and they also significantly differed (P＜0.05) in terms of dietary fiber, functional properties, total phenolic content, total flavonoid content and antioxidant activity of the peels. Conclusion: The quality of passion fruit peel can be greatly affected by the drying process, and microwave vacuum freeze-drying is the most preferred technique.

Objective: The purpose of this study was to investigate the drying characteristics and establish the kinetic model of Antarctic krill during spin-flash drying. The drying experiments were carried out at 120 ℃ to 180 ℃. Methods: Six common thin-layer drying models were selected to fit the experimental data. Further, the equations of drying model constant and temperature were established to obtain the model expression and validate the optimal drying model. The effective moisture diffusion coefficients were calculated by Fick's second law. Results: The results showed the drying temperature had a significant effect on drying thermal efficiency and drying rate. The spin-flash drying of Antarctic krill was a falling rate drying process at 130 ℃ to 180 ℃. The Page model was suitable for describing and predicting the spin-flash drying process of Antarctic krill. The constant term equations of the model were established by regression analysis, which were k=exp（-27.532 1+0.301 8T-8.538 2×10-4T2）and n=14.010 6-0.157 67T+4.750 9×10-4T2. As the drying temperature increasing, the effective moisture diffusion coefficient increased from 2.539 35×10-7 m2/s to 13.889 64×10-7 m2/s. Conclusion: The spin-flash drying method had the advantages of higher effective moisture diffusion coefficient and higher drying efficiency, which can effectively protect the thermal sensitive composition in Antarctic krill from being damaged and improve the product quality.

In this paper, the drying efficiency of natural drying, hot air and vacuum microwave on Auricularia auricula were systematically investigated, and the changes of physicochemical properties of Auricularia auricula and the degradation effect of quinolones (enrofloxacin, ciprofloxacin) were also evaluated. The results showed that the drying time of Auricularia auricula was greatly shortened to 150 min with the hot air drying (80 ℃) and 15 min with vacuum microwave (2.4 kW) compared with the natural drying. With the treatments of hot air drying and vacuum microwave drying, there was no significant effect on the content of crude protein, fat, fiber and ash in Auricularia auricula, and the total sugar content decreased by 1.34% and 2.28%, respectively. The physicochemical indexes still met the National Standard requirements. In addition, the degradation rates of enrofloxacin and ciprofloxacin during natural drying were 16.32% and 14.22%, while that of hot air drying were 35.37% and 32.39%, and vacuum microwave drying were 36.11% and 33.19%, respectively. The results indicated that there was no significant difference in antibiotic degradation between the two treatments. Therefore, vacuum microwave drying exhibits the advantages of less treatment time and effect on the physicochemical indexes, higher drying efficiency and better antibiotic degradation effect, which provides a new idea for the drying and quality control of edible fungi.

The aim of this study was to investigate the effects of different drying methods on the quality of dried yellow peach slices. Yellow peach slices were used as the research object, and vacuum freeze-drying (FD) and FD combined with microwave vacuum drying (MVD) and hot air drying (HAD) were used to dry yellow peach slices. The effects of different drying methods on the texture, microstructure, and nutritional composition of yellow peach slices were studied. The results indicated that compared with FD, combined drying methods could effectively shorten the drying time, the total sensory evaluation score and color difference of dried yellow peach slices obtained by vacuum freeze-drying microwave vacuum drying (FM) method were 91.60 and 18.97, respectively, which had little difference in texture characteristics and microstructure compared to the FD group. The nutrient content of FM dried yellow peach slices was significantly higher than that of the other combined drying methods (P

In order to explore the effects of different rice drying methods on physicochemical properties and taste quality of rice before and after soaking, the same variety of japonica rice after natural drying and hot air drying was used as the main raw material to explore the effects of different rice drying methods on water content, water distribution, microstructure, crystal structure, gelatinization characteristics, iodine blue value, taste value and texture characteristics of rice before and after soaking. The results showed that there were more cracks in the hot-air drying group, and the relative crystallinity, recovery value and gelatinization temperature were significantly lower than those in the natural drying group (P

In order to study the changes of volatile flavor components of Sparassis latifolia during postharvest storage at 4 ℃ with polypropylene film packaging, and dried by hot air and vacuum freezing, headspace solid phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used for detection and analysis. The results showed that a total of 30 volatile components were identified in the fresh S. latifolia, mainly consisting of 1-octene-3-alcohol, 3-octanol and trans-2-octene-1-alcohol. Compared to the fresh mushroom, the types of volatile flavor components in S.latifolia were increased during storage with polypropylene film packaging. The overall flavor components were similar in fresh mushrooms and mushrooms stored for 21 days, which mainly consisted of alcohols. While ketones and alcohols were the main flavor components of mushrooms stored from day 28 to day 49. Sixty-six volatile components were detected in mushroom dried by hot air and the relative content of 5-methyl-2-acetyl-furan was the highest (58.693%). Forty volatile components were detected in freeze-dried mushrooms, with relatively high relative contents of alcohols dominated by 3-octanol (41.567%) and ketones dominated by 3-octanone (45.723%), respectively. There was a significant difference in the overall flavor components between fresh mushrooms and hot air-dried mushrooms, while the overall flavor was relatively similar after freeze-dried. It can be seen that the polypropylene film packaging of fresh S. latifolia can maintain its original flavor well within 28 days of storage and freeze drying can better preserve the original flavor compared to hot air drying. This study contributes to a deeper understanding of the flavor characteristics of S.latifolia and can effectively distinguish different storage periods based on the rules of changes in volatile components, providing a theoretical basis for the improvement preservation methods and comprehensive development and utilization.

旨在为山桐子干燥方式的选择提供参考，分别采用热风干燥（HD）、微波真空干燥（VMD）、真空冷冻干燥（VFD）对山桐子鲜果进行干燥处理并采用溶剂浸提法提取山桐子油，测定山桐子油得率、酸值、过氧化值、脂肪酸组成、角鲨烯含量及挥发性物质组成，探究3种干燥方式对山桐子油品质的影响。结果表明，3种干燥方式制取的山桐子油得率大小顺序为VFD＞HD＞VMD，山桐子油酸值、过氧化值大小顺序均为VMD＞HD＞VFD（均未超出国标要求），山桐子油脂肪酸组成无差异，角鲨烯含量大小顺序为VFD＞VMD＞HD，主要挥发性物质均为烷类。综合比较，VFD方式制取的山桐子油品质最佳，适合少量实验；VMD方式干燥效率高，适用于快速干燥；HD方式制取的山桐子油品质介于二者之间，但此法操作简单，适合大批量处理物料时使用。Aiming to provide a reference for the selection of suitable drying methods for Idesia polycarpa, hot air drying(HD), vacuum microwave drying(VMD), vacuum freeze drying(VFD) were used respectively to dry the Idesia polycarpa fresh fruit and the oil was prepared by solvent extraction. The yield, acid value, peroxide value, fatty acid composition, squalene content and volatile substances composition of Idesia polycarpa oil (IPO) were determined to investigate the effects of three drying methods on the quality of IPO. The results showed that the order of the oil yield of the three drying methods was VFD＞HD＞VMD, the order of the acid value and peroxide value of IPO was VMD＞HD＞VFD (none of them exceeded the requirements of the national standard), there was no differences in fatty acid composition of IPO of the three drying methods, the order of the squalene content was VFD＞VMD＞HD, and the major volatile substances were alkanes of the three drying methods. By comprehensive comparison, IPO extracted after drying by VFD has the best quality and VFD is suitable for a few experiments. The drying efficiency of VMD is high, which is suitable for rapid drying.The quality of IPO extracted after drying by HD is between VMD and VFD, but HD is simple and suitable for processing materials in large quantities.

During oven drying of abalone muscle, microwave treatment was conducted at regular time intervals (0, 30, 60, 90 and 120 days). Abalone muscle digestion products (AMDP) were prepared by subjecting dried abalone to in vitro simulated digestion. Our aim was to investigate the effect of microwave treatment during the drying of abalone muscle on the in vitro and in vivo antioxidant activities of AMDP. The results showed that the half maximal inhibitory concentration (IC50) values of AMDP from fresh abalone muscle for scavenging capacity against hydroxyl (·OH) radicals, N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) and 1,1-diphenyl-2-phenylhydrazine (DPPH) radical were 3.04, 15.18 and 21.12 mg/mL, respectively. The IC50 values for the scavenging of these three radical species decreased gradually with increasing the drying time of abalone muscle. After being fed AMDP from abalone muscle dried for 120 days, the body length of Caenorhabditis elegans increased from 768.90 to 1 034.62 μm, the head swing frequency increased from 206 to 281 times/min, and the life span was extended by 36.16% under normal conditions and by 59.41% and 38.48% under heat stress and oxidative stress conditions, respectively compared with the control group. Meanwhile, with prolonging the drying time of abalone muscle, the antioxidant enzyme activities, reduced glutathione (GSH) content and total antioxidant capacity of C. elegans fed AMDP increased, and the reactive oxygen species (ROS) content decreased. In summary, prolonging the drying time and using microwave treatment during the drying process could improve the antioxidant capacity of AMDP.

In order to study the characteristics and quality changes of hot air drying (HAD) of prune, fresh prunes were used as raw material to investigate the quality changes under five different blanching conditions, and to investigate the changes of colour and aroma of prune during the hot-air drying process with different temperatures and air speeds. The results showed that the blanching temperature of 90 ℃ and the blanching time of 90 s could maintain better VC and anthocyanin contents (1.13, 12.42 mg/100 g) and inhibit peroxidase (POD) activity and polyphenol oxidase (PPO) activity (0.99 ∆OD470/min·mg, 0.57 ∆OD420/min·mg). The effect of drying temperature on time was more significant than that of air speed on time (P

In order to explore the effects of different drying methods on the microstructure and quality of dried products of Pleurotus eryngii, five methods were selected to dry the dried products: Hot air drying, microwave vacuum drying, intermittent microwave vacuum drying, hot air-microwave combined drying and vacuum freeze-drying , and the micromorphology, shrinkage rate, rehydration ratio, color, amino acid content, polysaccharide content and sensory evaluation of dry products were used as evaluation indexes. The results showed that vacuum freeze-drying was the best to maintain the integrity of tissue structure, with the smallest shrinkage rate (30.2%), the largest rehydration ratio (3.03), and the best recovery effect, the highest polysaccharide content (13%). The amino acid (560.94 mg/100 g) and sensory evaluation (9.4 points) of hot air-microwave combined drying were the highest, and the shrinkage rate (55.43%), rehydration ratio (1.83), color (76.29) and polysaccharide (11.8%) were the second highest after vacuum freeze-drying. The content of polysaccharide in hot air drying was the lowest (5.4%), and the sensory evaluation was the lowest (4.4 points). Comprehensive appearance, nutritional composition and sensory evaluation, hot air-microwave combined drying was a drying method most suitable for edible fungi with mycelium constitutes tissue and large water content such as P. eryngii.