红色猕猴桃果汁加工中色素的浸提及其理化特性研究

Extraction of Pigment in Red Kiwi Juice Processing and Its Physico-chemical Characteristics

为研制红色猕猴桃果汁,对红肉猕猴桃果汁加工中色素的浸提及理化特性进行了研究。结果表明,红肉猕猴桃中的红色素属于花色素苷类,适度热浸提有利于色素的浸出,果胶酶、纤维素酶等处理也可在一定程度上提高色素的浸出率;但由于对出汁率的提高幅度更大,造成果汁中色素浓度的降低。红肉猕猴桃果汁色素对酸碱较为敏感,在pH4.0以下时呈鲜艳的红色,在可见光区域内其最大吸收波长在516nm左右,但吸光度随着pH值的升高而大幅下降。长时间加热处理可造成红肉猕猴桃果汁色素的降解,低温避光有利于色素的保持。

In order to produce red kiwi juice, the extraction conditions of pigment in red kiwi juice processing and its physico- chemical characteristics were studied. Results showed that the pigment in red kiwi fruit was anthocyanins and proper thero-treatment was helpful to the extraction of the pigment. Furthermore, pretreatment of kwi fruit pulp with pectinase or cellulose could also increase the extraction rate of total pigment. But the juice yield increased more greatly resulting in the decrease of pigment in juice. The pigment in kiwi juice was sensitive to acid and alkai and turned fresh red at acid condition （pH〈4.0）. The maximum absorbance of the juice occurred at about 516nm in the region of visible light but the absorbance at 516nm decreased dramatically with the increase of pH. Heat treatment for long time could cause degradation of the pigment and darkness and low temperature were favorable for the pigment.