Vacuum and Infrared-Assisted Hot Air Impingement Drying for Improving the Processing Performance and Quality of Poria cocos (Schw.) Wolf Cubes

Abstract

The objective of this study was to develop an efficient drying technology for poria cubes in order to improve product quality. Poria cubes were dried using different methods, including air impingement drying, infrared-assisted air impingement drying, vacuum drying, two-stage vacuum drying, and infrared-assisted air impingement drying. The results were compared with those from hot air drying. For the two-stage drying, the tested conditions were the first stage of vacuum drying with temperatures between 65–85 °C and a switching moisture ratio of 70–90%. The second stage infrared-assisted air impingement drying also had temperatures 65–85 °C. The drying kinetics (effective moisture diffusivity (Deff), Biot number (Bi), and mass transfer coefficient (k) were studied via the product qualities (broken ratio, firmness, microstructure, and water-soluble polysaccharide content) and specific energy consumption (SEC) of the drying processes. The results showed that two-stage drying led to the lowest drying time and energy consumption, and also obtained the best qualities. Box–Behnken experimental design with response surface methodology (RSM) was used to optimize the two-stage operating conditions as 82 °C under vacuum drying until a moisture content of 81% and a temperature of 69 °C with infrared-assisted air impingement drying was achieved. These findings suggested that two-stage vacuum and infrared-assisted air impingement drying is a promising method for producing high quality and energy efficient dried poria cubes.

Drying kinetics of food materials in infrared radiation drying: A review

“…In assessing dryer energy performance, its thermal efficiency and SEC are considered by dividing the total energy supplied by mass of evaporated water (Nwakuba, Asoegwu, & Nwaigwe, 2016). SEC in the drying process (MJ/kg), which is the energy needed to remove 1 kg water of the moist product was estimated using the following expressions (W. Zhang, Chen, Pan, & Zheng, 2021): where E is the energy consumed during drying in MJ, and m water is the mass of moisture removal during the drying in kg.…”

“…Kaveh, Abbaspour‐Gilandeh, and Nowacka (2021) evaluated the SEC for the drying of green pea in convective, IR, microwave, convective‐vacuum, convective‐IR, convective‐microwave, convective‐rotary, IR‐rotary dryers and reported the SEC values in the range of 12.15–215.45 MJ/kg. W. Zhang et al (2021) reported the lowest SEC value of 1.38 MJ/kg during IR‐assisted air impingement drying of poria cubes. Tezcan, Sabancı, Cevik, Cokgezme, and Icier (2021) observed the SEC values of 3.77–4.45 kJ/kg during the thin‐layer drying of dill leaves in a continuous type IR dryer.…”

Aloe vera Gel Drying by Refractance Window®: Drying Kinetics and High-Quality Retention

“…Over 85% of industrial food dryers are convective, with mostly hot air as the media for heat transfer; often resulting in significant levels of changes in product quality from the initial fresh-like form [ 17 ]. Along with food quality retention, energy efficiency is equally important in the drying process, which is why both aspects are the subject of intensive research and development on food science [ 18 , 19 , 20 , 21 ]. Among the technologies currently deployed for the drying of valuable products, freeze-drying is very expensive, and despite the high-quality of its products, its use is limited to high-value products [ 15 , 18 , 22 ].…”

Postharvest processing of tree nuts: Current status and future prospects—A comprehensive review

“…Simultaneously, because tree nuts are rich in unsaturated fatty acids (Curb et al, 2000;Gecgel et al, 2011;Ros & Mataix, 2006;Virtanen et al, 2014), the oil quality of tree nuts is sensitive to the thermal drying process Chen, Venkitasamy, Zhang, Deng, et al, 2020;Zhang et al, 2020). Thus, the drying practices of tree nuts need to be conduct appropriately and efficiently right after harvesting to ensure the quality, safety, and market value of dried products (Ajith et al, 2015;Chen, 2021;Tavakolipour, 2015;Zhang et al, 2018;Zhang, Chen, et al, 2021).…”