浓缩苹果清汁色值下降问题的研究

The decline chromaticity value of concentrated apple juice

浓缩苹果清汁因原料种类、加工工艺和保存条件不同,而造成果汁色值下降速度不同。有效控制色值下降,防止果汁的营养损失是关键。 色值下降机理 果汁的色素主要是酚类色素,如花青素、花黄素和鞣质等,这些色素都极不稳定。由于苹果在破碎过程中,作为呼吸传递的酚醌氧化还原系统受到破环,酚羟基氧化为醌型结构,醌大量聚集,醌一旦形成后会引起两种情况:一是羟醌自动聚合,随聚合程度增大,由红变褐,最后形成褐黑色素物质;二是醌和氨基酸发生非醌的缩合反应。

The declining speed of chromaticity value of concentrated apple juice in processing depends on raw materials, processing techniques and storage conditions of the product. In order to control the declining speed effectively and preserve the nutrition of apple juice, some key factors must be considered. Here we provide some suggestions for the processing.