Efficient Production of Dried Whole Peanut Fruits Based on Infrared Assisted Spouted Bed Drying

Anti-mildew and fresh-keeping effect of Lactiplantibacillus paraplantarum P3 cell-free supernatant on fresh in-shell peanuts during storage process

Lactiplantibacillus paraplantarum P3 (L. paraplantarum P3) cell-free supernatant (CFS) with good antifungal effect was sprayed on fresh in-shell peanuts stored at 5 °C and 30 °C to explore its effect on the microorganisms and quality of fresh in-shell peanuts during storage process. Results showed that L. paraplantarum P3 CFS effectively maintained good quality of fresh in-shell peanuts by not only reducing fungi amount and the mildew rate, but also improving the morphology, color and flavor. Besides, L. paraplantarum P3 CFS activated plant mitogen-activated protein kinase signaling pathway and plant hormone signaling pathway to produce more ethylene, gibberellin regulatory proteins and other substances to enhance plant resistance to pathogenic microorganisms. L. paraplantarum P3 CFS could also induce the biosynthesis of glycerophospholipid and arginine to increase the stress resistance of fresh peanuts. This study provides research data for the application of L. paraplantarum P3 CFS in the preservation and antimildew of fresh in-shell peanuts.

Effect of constant and variable temperature drying processes on drying characteristics, quality, and volatile profile of rose petals in infrared-assisted spouted bed drying

The edible rose (Rosa Crimson Glory) petals were dried using infrared-assisted spouted bed drying technology. The effects of different drying temperature conditions (30, 35, 40, 45, and 50°C, as well as stepped heating drying [SHD] and stepped cooling drying) on the drying characteristics, physicochemical properties, antioxidant capacity, and changes in volatile flavor compounds of the rose petals were investigated. The results showed that the drying time was shortened with increasing drying temperature. Both variable temperature drying processes gave the shortest drying times. Optimal color retention of rose petals was achieved at a constant temperature of 40°C and SHD. Increased drying temperature resulted in higher water-soluble polysaccharide content in the dried rose petals, whereas lower temperatures facilitated anthocyanin preservation. The variable temperature drying processes favored the retention of water-soluble polysaccharides in rose petals, but not anthocyanins. Regarding antioxidant capacity, the samples dried at 40°C and those subjected to the two variable temperature drying processes performed better. This study also analyzed the differences in volatile flavor compounds of rose petals dried under different drying conditions. It was found that the majority of volatile flavor compounds in the rose petals dried by SHD exhibited higher content levels than the other drying conditions. Therefore, considering a thorough evaluation of all relevant factors, it was clear that utilizing the SHD process was the most efficient method for obtaining the best quality rose petals overall.

Efficient Production of High-Quality Infrared-Assisted Spouted Bed-Dried Areca taro Based on the Drying Temperature and Cutting Size Control

The purpose of this study was to apply infrared-assisted spouted bed drying (IRSBD) technology for Areca taro drying and to investigate the effects of different parameters on its drying quality. Specifically, in order to determine the suitable conditions for IRSBD, the effects of different drying temperatures (45 °C, 50 °C, 55 °C, and 60 °C) and cutting sizes (6 × 6 × 6 mm, 8 × 8 × 8 mm, 10 × 10 × 10 mm, and 12 × 12 × 12 mm) on the drying characteristics, temperature uniformity, and quality properties (including colour, rehydration ratio, total phenol content, total flavonoid content, and antioxidant activity) of Areca taro were studied. The results showed that the optimal drying condition was the sample with a cutting size of 10 × 10 × 10 mm and drying at 50 °C, which yielded the dried sample with the best colour, highest total phenol and flavonoid contents, maximum antioxidant capacity, and rehydration ratio.

Development and evaluation of a hybrid smart solar dryer

A hybrid smart solar dryer (HSSD) based on indirect forced convection and a controlled auxiliary heating system was developed, fabricated, and tested to be convenient for sunny and cloudy weather conditions. The achievements of the developed dryer focus on controlling the temperature of the dryer, increasing the drying rate, reducing energy consumption, and providing high-quality products. The HSSD was tested and evaluated for drying basil and sage herbs at 30, 40, and 50°C. The results showed that the fresh basil and sage leaves of 1 kg with a moisture content of 84.7% and 75.53% (wet basis) were dried within 58, 46, 32 and 38, 28, and 20 h at 30, 40, and 50°C, respectively. Correspondingly, the traditional drying methods achieved 96 h outdoors and 144 h indoors at room temperature. The average of the fabricated flat-plate solar collector efficiency (thermal efficiency, ηfpsc ) was ranged from 49.18% ± 9.52% to 66.02% ± 2.8%. The highest drying rates were achieved with the HSSD method. Moreover, the HSSD method led to a remarkable saving in energy with values ranging from 25.54% to 77.1% versus the traditional drying methods. While the best quality in terms of essential oil content and microbial load for the dried basil and sage herbs was achieved by the HSSD at 40°C. Finally, the HSSD is a promising energy-efficient method where it can save 70% of energy consumption, thus reducing the carbon footprint of drying processes, and providing higher quality products compared to the conventional methods.

Infrared-assisted spouted bed drying of Chinese yam cubes: effect of constant and variable temperature drying processes on drying behavior, uniformity, and quality attributes

BACKGROUND

Infrared-assisted spouted bed drying (IRSBD) is an innovative hybrid drying technology based on infrared drying and spouted bed drying, which has the advantages of higher drying efficiency and better uniformity. Temperature is an important process parameter that affects drying characteristics and product quality. Considering the overall quality of the product, drying at a constant temperature may not be the best solution. However, there is a lack of research on dynamically varying drying schemes. In this study, the effects of constant and variable temperature drying processes on the drying characteristics, uniformity, energy consumption, and quality of Chinese yams were evaluated.

RESULTS

The shortest drying time and lowest energy consumption were obtained by IRSBD at 70 °C, followed by staged rising temperature drying (SRTD). However, SRTD achieved the best drying uniformity. The Peleg model could describe the dehydration kinetics of dried yams well (R²  > 0.99). A high drying temperature (70 °C) favored the preservation of bioactive compounds (polyphenols and flavonoids) and gave the best antioxidant activity and equilibrium rehydration ratio of dried yams but resulted in poor color. Samples dried with SRTD showed comparable good antioxidant activity and better color than those dried at 70 °C.

CONCLUSION

A reasonable variable temperature drying scheme using IRSBD is considered to be better when considering the drying performance and overall quality of the products. © 2022 Society of Chemical Industry.