Optimization of drying conditions of black shallot
by heat pump technology
Authors: Tran Phuong Chi, Nguyen TanThanh, Hoang Thi Le Hang, Tran Dinh Thang
Journal of Vietnam Academy of Agricultural Sciences
: Số 04(137)/2022 : 69-76
Publishing year: 6/2022
e purpose of this study is to determine the optimal conditions for the heat pump drying process to improve
the recovery of total phenolic and ¯avonoid content from black shallot and investigate its nutritional components.
Experiment was designed according to the centered structure plan (CCD). As a result, an optimal model of the heat
pump drying process was built with three factors: drying temperature (X1), drying time (X2) and drying speed
(X3); three responses were loss of phenolic content (Y1, %), loss of ¯avonoid content (Y2, %), moisture content
(Y3, %). e optimal parameters of the heat pump drying process were the drying temperature of 53oC, the drying
speed of 2.3 m/s and the drying time of 20 hours. Under this condition, the lowest loss of total phenolic content was
11.45 ± 0.05%, the lowest loss of total ¯avonoid content was 12.80 ± 0.04% and moisture content was 13.11 ± 0.05%.
Keywords: Black shallot (Allium ascalonium), heat pump drying process, drying conditions