ẢNH HƯỞNG XỬ LÝ NHIỆT KẾT HỢP DUNG DỊCH MÀNG PHỦ BẢO QUẢN LÊN CHẤT LƯỢNG NHÃN ‘TIÊU DA BÒ’ TRONG ĐIỀU KIỆN TRỮ LẠNH

To evaluate the effect of heat treatment in combination with preservative coating solutions on quality of “tieu da bo” longan fruit under low temperature storage. Two experiments were established as follow: (i) the first experiment was done by dipping the longan fruits into 1% (w/v) chitosan coating of citric acid solution having (pH=2.4; 2.5; 2.6 and 2.,8); 0.5% (w/v) commercial citrex coating solution (pH=3.3) and water (as the control) for 0.5; 1; 2 and 4 minutes and finally packed in PE holed bags and stored at 5oC; the second experiment was done by submerging the fruits in hot water at temperatures of 45; 47 and 49oC for 4 minutes and followed by dipping into the best preservative coating solution treatments, which were selected from the 1st experiment and finally packed in PE holed bags and stored at 2, 5 and 10oC. Results from these two experiments are summarized as follows: (i) longan fruits treated with the chitosan coating solution at pH 2.6/ 2 minutes or citrex at pH3.3/4 minutes could be maintained the good fruit quality for 21 days at storage temperature of 5oC. (ii) Hot water treatment at 47oC and then dipped into a solution of citrex (pH 3.3)/4 minutes and finally storaged at 5oC was the best combinated treatment to control browning pericarp and maintain quality of longan for 21 -28 days.