羧甲基壳聚糖对牛奶葡萄的保鲜效果研究

以虾、蟹等动物甲壳为原料，通过新的实验方法和工艺制备水溶性壳聚糖衍生物——羧甲基壳聚糖，并以此为主剂，以阿拉伯胶等为助剂制成不同性质的复合保鲜剂，配以不同浓度的复合保鲜剂水溶液喷涂于牛奶葡萄表面，于0～0．5℃的冷库内存放进行保鲜实验。结果表明：保鲜过的葡萄基本上保持了原有的色、香、味；葡萄梗仍为绿色，无霉变。储存180d后，牛奶葡萄失水率为1．56％，脱粒率为2．1％。可滴定酸含量为0．3％（质量分数），100g样品中VC含量为1．59mg，还原糖含量为14．1％（质量分数）。该保鲜剂中的羧甲基壳聚糖和阿拉伯胶均来源于天然生物，具有食品安全性，无污染，符合《绿色食用葡萄标准》。

Study of keeping milk grape fresh by using carboxymethyl chitosan in storage

A new method for preparing a water soluble derivation of chitosan,named as carboxymethyl chitosan,from chitosan in shrimp or crab was studied in this paper.Compound preservations were made with carboxymethylchitosan as main reagent and gum Arabic as auxiliary.Different concentration water solution of the compound preservations were sprinkle or spread on the surface of the milk grapes,and then the grapes were preserved at 0～0.5 ℃.The results showed that the grape preserved with compound material mainly kept its original color,fragrant,taste,and the stalk remained green after 180 days.The loss rate of water is 1.56 %,the rate of threshing is only 2.1%,the concentration of the titratable acid is 0.3%,the vitamin C is 1.59 mg/100 g and the reducing suguar is about 14.1%.Carboxymethyl chitosan and gum Arabic come from natrual organism,so the self-made compound preservations meet the requirement specified in the regulations of Non-polluted Grapes Standards.