Abstract:Five different drying temperatures, that is 40, 45, 50, 55, and 60 ℃, and natural drying (temperature range 30~35 ℃) were set for the drying test to explore a suitable temperature condition for drying wolfberry (Lycium barbarum). The physicochemical indicators were analyzed and tested in terms of the effects of temperature on drying duration, rehydration ratio, color, browning degree, and bioactive substances such as Lycium barbarum polysaccharide (LBP), flavonoids, and carotenoids. An optimal drying temperature was selected by determining the weights with the coefficient of variation method. The results showed that the nutritional composition of Lycium barbarum products dried at the five different temperatures changed significantly. The temperature had relatively great influences on five indicators, namely drying duration (weight: 0.317 0), browning degree (weight: 0.224 7), rehydration ratio (weight: 0.141 4), flavonoids (weight: 0.100 1), and LBP (weight: 0.065 2), among which drying duration was most affected. The results of the overall evaluation of drying temperatures were as follows: drying under 45 ℃ (overall score: 0.430 5) > drying at 40 ℃ (overall score: 0.402 6) > natural drying (overall score: 0.140 7) > drying at 50 ℃ (overall score: 0.011 2) > drying at 55 ℃ (overall score: -0.317 6) > drying at 60 ℃ (overall score: -0.668 2). The highest score was achieved at 45 ℃, and the quality of wolfberry was the best at this temperature. Therefore, 45 ℃ was selected as the optimal drying condition.
