酒精发酵及陈酿中不同因素对葡萄果皮色素稳定性的影响

Effect of different factors on the stability of grape skin pigment in alcoholic fermentation and aging process

本试验通过分光光度法，研究不同梯度的酒精度、pH值、SO2浓度、温度以及光照对葡萄果皮中色素（花色苷）稳定性的影响。结果表明，发酵过程酒精度在10％～13％（V／V）时，对花色苷的浸提效果好；酒精度大于13％（V／V）时，对花色苷的浸提效果减弱。发酵温度应在30℃以下，高温会破坏其色素结构，使其变淡。较高SO2浓度会造成褪色现象，理想状态在50mg／L左右。陈酿过程要完全避光，光照会造成色素衰退，酒体老化。环境温度应控制在10～15℃之间，较高的温度会造成褪色。pH2～4变化范围内，葡萄酒颜色可以保持其最佳状态，呈现宝石红色；pH2〉4，酒体会出现老化的褐色及灰绿色。

The spectrophotometric method was used to study the effects of different alcoholicity, pH, SO2 concentration, temperature and light intensity on the stability of grape skin pigment （anthocyanin）. The results showed that the anthocyanin extraction efficiency was better with alcoholicity between 10% and 13%（V/V） during alcoholic fermentation and the extraction efficiency decreased when the alcoholicity was 13% plus. The fermentation temperature should be controlled under 30 ℃, otherwise the color would fade with its structure destroyed by higher temperature. High SO2 concentration could cause discoloration, so the concentration should be controlled at about 50 mg/L. The wine should be kept away from light during aging or it could cause discoloration and wine body deteriorating. Environment temperature should be keep at 10-15 ℃and higher temperature would cause bleaching. The red wine color could be the best ruby red when pH between 2 and 4, while the wine would appear brown and grey green when pH over 4.