Drying Kinetics, Physicochemical and Thermal Analysis of Onion Puree Dried Using a Refractance Window Dryer

Onions have a high moisture content, which makes them more susceptible to microbial growth. Drying is one of the postharvest preservation methods applied decrease onion thereby increasing its storage life. In this study, onions were peeled, washed, cut into quarters, hot water blanched, and pureed. The puree was further dried using two different drying methods: refractance window (RWD) (water temperature: 70 °C) convective (CD) (50 °C). spread on prefabricated trays at varying thicknesses 2 mm, 4 6 mm. It observed that, irrespective method, ratio (MR) decreased time effective diffusivity increased with respect thickness puree. addition, Lewis model Wang Singh showed highest R2 lowest SEE value for RWD CD, respectively. Moreover, MR during CD predicted multi-layer feed-forward (MLF) artificial neural network (ANN) back-propagation algorithm. result that ANN 12 18 neurons in hidden layer could predict MR, results also method significantly affected physicochemical quality (color characteristics, pyruvic acid total phenolic flavonoid antioxidant capacity, hygroscopicity) powder. concluded proved be better than terms powder reduced time. Irrespective mm-thick yielded best-dried quality, as well yielding These samples analyzed calculating glass transition temperature.