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The final particle moisture content of ceramic slurry spray drying affects the processing, product quality, and process energy consumption. While the real-time moisture content determination is very difficult for spray drying process due to nonlinear, severe lag, interference factors, and complexity of the systems, the high temperature, high humidity drying environment and short drying process. In current work, an improved moth optimization (IMFO) algorithm combined with backpropagation neural network (BPNN) was proposed to predict the moisture content of ceramic slurry particles during spray drying. The performance of the model is trained and tested. Results demonstrate that IMFO has better convergence ability and speed compared to other algorithms such as particle swarm optimization (PSO) and gravitational search algorithm (GSA). The IMFO-BPNN model achieves a MAE of 0.0293, RMSE of 0.0383, and R2 value of 0.9113, outperforming the prediction performance of BPNN and MFO-BPNN models. The absolute error rate of the IMFO-BPNN model (0–5%) is lower compared to BPNN (5–10%) and MFO-BPNN model (>10%), showcasing superior accuracy in predicting moisture content. This mathematical model established in the study provides an efficient, accurate, and nondestructive method for predicting the drying endpoint of ceramic slurry spray drying. [ABSTRACT FROM AUTHOR]

In this study, a tunnel-type continuous multi-physical field drying equipment was developed to combine microwave, hot air, and infrared drying technologies. The microwave source arrangement and hot air equalizing plate were optimized based on numerical simulation to enhance the uniformity of the microwave field and hot air velocity distribution. Mode 4 and opening ratio 37.70% (r = 60 mm) were had the highest electric field distribution and hot air distribution. This equipment was further used to pre-dehydrate cowpeas and the effects of microwave, hot air, and infrared on food drying properties and quality of dried samples were investigated. The results showed that the moisture content was reduced by 20% and the ΔE value greater than 5 after pre-dehydration. Microwave treatment rapidly reduced the moisture content of cowpeas. The infrared treatment significantly improved the uniformity of temperature distribution and the texture profile of the dried sample. The hot air drying increased 10 °C for the overall temperature of the food material and balanced the internal water content of the food material. This study aims to provide future researchers with insights to develop novel microwave-based continuous drying equipment for its commercial applications. [ABSTRACT FROM AUTHOR]

In view of the problems of short storage periods, high cost, and high energy consumption in low-temperature storage and controlled atmospheric storage of garlic sprouts, pulsed vacuum drying (PVD) technology was applied in this study for improving the commodity value and reducing the storage cost of garlic sprouts. The drying characteristics and quality attributes of garlic sprouts at different temperatures (65, 70, and 75 °C) and pulsing ratios (2:4, 3:4, 4:4, 3:2, and 3:6) based on the different heating techniques of infrared radiation (FIR-PVD) and electronic panel conduction (EPC-PVD) were investigated. The results showed that EPC-PVD shortened drying time by 11.45–24.94% compared with FIR-PVD, while FIR-PVD achieved better quality in terms of color and allicin retention as compared with EPC-PVD. Prolonging the vacuum duration and reducing the atmospheric pressure duration were helpful in the formation of porous structures, thus obtaining a faster drying rate and better product quality. The Weibull model could precisely describe the drying kinetics of garlic sprouts. FIR-PVD at 75 °C and 3:4 was recommended as the most suitable drying condition due to the highest comprehensive score (0.7856) considering drying time and product quality. The findings provide a new idea for low carbon high-quality storage of garlic sprouts. [ABSTRACT FROM AUTHOR]

Lemon flavedo is distinguished by their unique and abundant volatile flavor compounds that can undergo complex changes during drying. In this study, integrated freeze drying (IFD), conventional freeze drying (CFD), and hot-air drying (AD) were employed to dry lemon flavedo to investigate the changes and correlations of volatile compounds, fatty acids, and key enzymatic activities during the drying process. The results showed that IFD retained the most volatile compound types, followed by CFD and AD. Furthermore, after drying, IFD, CFD, and AD had lost 47.92 mg/g, 56.07 mg/g, and 13.22 mg/g of total volatile compounds, respectively, compared with fresh samples, and the content loss rates of total fatty acids were 77.38% in AD > 72.95% in CFD > 56.54% in IFD, respectively. During the three drying processes, IFD retained relatively higher enzyme activity in the samples. Lots of positive and negative correlations (P < 0.05) were observed among the key enzyme activities, fatty acids, and volatile compounds, showing close associations. The current work provides important information for selecting suitable drying techniques of lemon flavedo and shows lights on how to control its flavor during drying process. [ABSTRACT FROM AUTHOR]

A novel combined drying technology, namely infrared-assisted tilted tray air impingement drying (IR-TTAID), was developed in this study. Drying time, energy consumption, and quality of kiwifruit slices were evaluated. Compared with TTAID, IR-TTAID reduced the drying time by 35.71%–58.33% and the energy consumption by 5.96%–27.92%, as well as obtained better quality in terms of color, shrinkage, and vitamin C content. The Page, Weibull, and Dincer models could precisely describe the drying kinetics of kiwifruit slices, of which the Page model theoretically revealed the higher drying capacity of IR-TTAID due to the minor internal resistance to water transfer. Scanning electron microscope observed more porous structures in IR-TTAID samples, which was conducive to the moisture migration during the drying process. IR-TTAID at 60 °C is recommended as the most suitable drying condition considering drying efficiency and quality. The finding provides important information for promoting the industrial production of dried kiwifruit slices. [ABSTRACT FROM AUTHOR]

Hot air impingement drying (HAID) was employed to dry Amomum villosum (A. v.) fruit, one of the most popular traditional Chinese herbs and functional foods, under different drying temperatures, air velocities and the drying characteristics and quality were evaluated. The drying time decreased from 12 to 4 h, 10 to 8 h with the increase of temperature and velocity from 50 to 70 °C, 3 to 9 m/s, respectively. Weibull model precisely described the drying behavior. The highest total flavonoid content was obtained at 60 °C with low shell burst ratio. As for essential oil components, the relative content of monoterpenoids increased while sesquiterpenes decreased with increasing temperature. The acids and alcohols contents decreased with increase in velocity. By considering both drying time and quality, 60 °C and 6 m/s was proposed as the most favorable condition. The findings indicate HAID is a promising drying method for A. v. fruit. [ABSTRACT FROM AUTHOR]

The effects of three different drying tecnologies (PVD, THC-HAD, and IR-HAD) on drying kinetics, microstructure, energy consumption, and quality, that is, rehydration ratio (RR), color parameters (L*, a*, b*), total color difference (△E), Panax Notoginseng saponins (PNS) content, and ginsenosides content (R1, Rg1, Re, Rd, Rb1) of Panax Notoginseng roots were examined experimentally. As expected, the drying time decreased with increase of drying temperature from 40 to 70 °C, and PVD needed the shortest drying time, followed by THC-HAD and IR-HAD. The drying time of PVD was reduced by 22.9% and 30.2% compared with THC-HAD and IR-HAD at 60 °C, respectively. PVD can effectively shorten the drying time, and the dried samples had better brightness (about 50.2 ± 1.3), rehydration ability (range from 1.6 to 2.1) through promoting the porous structure formation of dried roots. But PVD is not the most suitable drying technology in terms of ginsenosides content preservation and energy consumption, when compared to THC-HAD and IR-HAD. For Panax Notoginseng roots need to be used as medicine, IR-HAD is a promising drying technology, especially at 50 °C, as it allowed high retention of PNS (about 12.5%) and low unit energy consumption (about 19.5 kW·h/kg). Therefore, the current findings indicate that IR-HAD drying has the potential to produce high-quality dried Panax Notoginseng roots on commercial scale. [ABSTRACT FROM AUTHOR]

Lemon fruits have a non-uniform histological structure, and are characterized by abundant volatile compounds. However, the distribution of volatile compounds in different tissues remain unknown. Herein, electronic nose (E-nose) and headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS) were employed to qualitatively and quantitatively analyze the volatile compound content in different tissues of fresh lemon fruits, while their microstructures were observed using several microscopy methods. The numbers of volatile compounds detected in the flavedo, albedo, juice vesicles, and segment wall were 41, 23, 29, and 19, respectively. The volatile compounds detected in the four tissues were mainly alkenes, alcohols, aldehydes, esters, and ketones, with a significant descending order in the total content (p <.05). The measurements of E-nose and HS-SPME-GC-MS both showed that the highest total content of volatile compounds was in the flavedo, followed by albedo, juice vesicles, and segment wall (p <.05). Furthermore, oil sacs and oil droplets were only observed in the flavedo by microstructure observation, where more essential oils (mainly volatile compounds) were distributed. The microstructure observation results also verified the measurement results of the E-nose and HS-SPME-GC-MS. These findings provide basic data for sensory evaluation and the comprehensive processing and utilization of lemon fruits. [ABSTRACT FROM AUTHOR]

In order to explore the feasibility to enhance drying kinetics, the effects of pulsed vacuum drying (PVD) under different temperatures (55, 60, 65, 70, and 75 °C) and pulsed vacuum ratio (PVR) (3:16, 6:16, 9:16, 12:16, 9:10, 9:13, and 9:19 min/min) on the drying kinetics, energy consumption, and quality attributes of Panax notoginseng roots in terms of color parameters (L*, a*, b*, and △E), the contents of ginsenosides (R1, Rg1, Re, Rd, Rb1), and Panax notoginseng Saponins (PNS) are evaluated. The results were compared with those obtained under hot air drying (HAD) conducted at the temperature of 60 °C, relative humidity of 12%, and air flow rate of 0.3 m/s. PVD at 75 °C and PVR of 9:16 min/min resulted in the shortest drying time, i.e., 26.6 h, while PVD at the temperature of 65 °C and PVR of 9:13 resulted in the highest PNS content, i.e., 9.03%. Among different drying conditions, the temperature of 65 °C and PVR of 9:16 min/min are recommended as the most suitable ones for drying of whole Panax notoginseng roots in terms of drying time, energy consumption and quality of final product. [ABSTRACT FROM AUTHOR]

Camellia oleifera seed, one of the most important woody oilseeds, is being paid more and more attentions for the favorable functional characteristics of the oil. In order to obtain Camellia oleifera seed for oil production, a series of postharvest processing steps, including the shelling of Camellia oleifera fruits and drying of Camellia oleifera seeds are necessary. After postharvest processing, it is essential to maintain quality of the seeds through storage over a long time. This review focused on the recently published research on different techniques that could be applied in postharvest processing and storage of Camellia oleifera seeds. Based on the recent advances, the development trends were put forward for further research, which will provide references to improve the quality of stored Camellia oleifera seeds. [ABSTRACT FROM AUTHOR]

The objective of this research was to examine the drying characteristics of pulsed vacuum drying (PVD) system as an alternative drying technology for a functional food—Poria cocos. Poria cubes in thin layer were dried at different temperatures (55, 65, and 75°C), vacuum duration (5, 15, and 25 min), and atmospheric pressure duration (4, 8, and 12 min) to evaluate the operating conditions on the drying kinetics and quality attributes of P. cocos. The quality attributes included volume shrinkage ratio, firmness, water-soluble polysaccharide content. Volume shrinkage ratio was determined by image processing technology and analyzed by Bigot’s curves. The material internal temperature was also recorded during the whole drying process. Considering the drying rate and quality attributes, drying temperature of 65°C, vacuum pressure duration of 15 min, and atmospheric pressure duration of 4 min were proposed as the most favorable drying conditions for drying Poria cubes. The current work indicates PVD is a promising technology for P. cocos drying as it not only enhances the drying process but also improves the quality attributes of it. [ABSTRACT FROM AUTHOR]