关键词: 荔枝干, 护色, 硫处理

Abstract: This study was conducted on the color retention of dried Litchi fruit.The treatments were as follows:fresh litchi fruit was bleached by dipping in three different solutions(Sldium dithionite,Sodium bisulfite and Sulfurizafion)firstly;then dipped in three different acid solutions(HCL,H2SO4 and Phytic acid)at different pH value(0.5,1.0 and 3.0)for different time(5,10 and 15 min)respectively Then after it was dried only in the daytime at 50～60℃.When water content in the pulp reached 29％～32％,the product yidld was 25％～28％. The results showed that the kinds of acid,pH and the dipping time made a little different effect on skin color retention and sensory of fruit.The opfimal effect was obtained by smoking first,then soaking in H2SO4 solution at pH3 for 5 min.After drying the skin color almost kept the initial color and the pulp had the characteristic favor of litchi without residual taste of sulphiteAffer assoy,the total acidity rose,total sugar and redued sugar changed a little,Vc decreased greatly and the residul guiphite was in trace amount compared with the control. The results of storage experiment of products showed that the skin color kept a natural redness,and the pulps did not mildew and had no monstrous flavor after more than one year storage at room temperature sealed in freshing package.

Key words: Dried litchi Color retention Sulphite treatment