混浊苹果汁加工过程中的的酶促褐变及其防止的研究

将几种可用于食品的防褐变剂在苹果破碎时加入,考察了它们对苹果浆和苹果鲜榨汁的防褐变效果及它们之间的协同作用.半胱氨酸、抗坏血酸、曲酸、氯化钠和氯化钙都是较好的防褐变剂.在所测试条件下,抗褐变的能力(褐变抑制率)为0.1%的抗坏血酸＞0.1%的偏重亚硫酸钠＞0.1%的曲酸＞0.1%的氯化钙＞0.005%半胱氨酸＞0.1%氯化钠.它们抗褐变能力都表现为浓度依赖型,特别是抗坏血酸.柠檬酸在所测试条件下没有抗褐变效果.0.044%NaCl+0.0125%Vc的组合较经济且可使果汁40min不变色.果浆脱气可减缓其褐变;减小果汁及果浆与空气的接触面也可防止褐变.

Enzymatic browning and its prevention in the processing of cloudy apple juice

When apples were crushed some anti -browning agents being suitable for food were added and their abilities to inhibit the enzymatic browning in apple mash and juice as well as their synergistic effect were investigated. Cysteine, ascorbic acid, kojic acid, NaCI and CaCI2 are all effective inhibitors of enzymatic browning and their inhibition abilities were: 0.1% Vc >0.1% sodium metabisulfite>0.1% kojic acid>0.1% CaCI2>0.005% cysteine >0.1% NaCI. The inhibition abilities depended largely on their concentration, especially for ascorbic acid. Citric acid failed to inhibit the enzymatic browning in apple mash and juice in the test. The combination of 0.044% NaCI +0.0125% Vc could inhibit completely the enzymatic browning in apple juice for 40 minutes and this combination proved to be more economical for large scale production. Removing the gas in apple puree could delay its enzymatic browning. Reducing the contact of juice and puree to air could also inhibit enzymatic browning in them.