不同分子量壳聚糖对草莓果汁的澄清作用

Effect of Chitosan with Different Molecular Weight on Clarification of Strawberry Juice

用过氧化氢法或酶法降解壳聚糖制备了不同分子量的壳聚糖,并用凝胶渗透色谱测定了降解产物的分子量。该系列壳聚糖样品被用于对草莓果汁进行澄清。实验结果表明:壳聚糖对草莓果汁具有澄清效果,在0.2%浓度,随着壳聚糖分子量的增大,澄清效果增强;分子量Mw1.3×105以上壳聚糖剂量达到最佳后,增加壳聚糖,澄清效果反而下降;分子量Mw6.3×104以下的壳聚糖,在实验浓度条件下,澄清效果均不理想;中间分子量的壳聚糖剂量达到最佳后,再增加壳聚糖的剂量,澄清效果基本不变。脱乙酰度在73.1%～92.8%范围内的壳聚糖的澄清效果并无明显差异;果汁在pH3～5范围内,对澄清效果的影响不大;15～60℃温度范围内对壳聚糖澄清草莓果汁的影响不大;使用壳聚糖作为草莓果汁的澄清剂对原汁主要营养成分无明显影响。

Chitosans with different molecular weight were prepared by H_2O_2/HAc or enzymic degradation, and the molecular weights were determined with Gel Permeation Chromatography (GPC). Effect of different chitosan in clarification of strawberry juice was studied. Clarification effect of chitosan (Mw >1.3×10~5) increased with increasing dosage, and then decreased with further increasing dosage. Clarification effect of chitosan with Mw 1.3×10~5～6.3×10~4 kept stable after reaching the best. The degree of deacetylation of chitosan in range of 73.1% to 92.8% had little effect on its clarification. The clarification effect are all rather fine at pH 3～5. There is no significant difference on the main nutrients by the different treatments of chitosan.