煮制条件对绿豆清汤颜色及抗氧化性的影响

摘要

Objectives： To investigate the relationship between color values and antioxidant activity of mung bean clear soup（MBCS） and the effects of water type,granule sugar,table salt and sodium bicarbonate on them.Methods： Phenolic contents（total phenols,total flavonoids and condensed tannins）,pH value,color values（L＊,a＊ and b＊） and antioxidant properties（DPPH free radical scavenging ability and FRAP value） of MBCS during cooking were tested and the correlations among these parameters were analyzed.Results： The color values and antioxidant activities of MBCS increased with increasing amount of dissolved phenols.Deionized water resulted in increased phenolic contents and antioxidant activity of MBCS compared to tap water.The antioxidant activities of MBCS were decreased by addition of sodium bicarbonate or granule sugar but increased by addition of salt.There was a strong correlation between the b＊ and antioxidant activities of MBCS.Conclusion： Phenols mainly contribute to the color and antioxidant activities of MBCS and influences the pH.Slightly acidic water is favorable for the preparation of green MBCS with strong antioxidant activity.%目的：研究绿豆清汤煮制过程中颜色与抗氧化能力变化的关系,考察煮制用水及添加白砂糖、食盐、小苏打等辅料的影响。方法：对煮制过程豆汤中酚类物质（总酚、总黄酮、缩合单宁）含量、pH值、颜色（L＊值、a＊值、b＊值）及DPPH自由基清除率和FRAP（ferric reducing ability of plasma）值等抗氧化指标进行测定,并进行相关分析。结果：随着酚类物质溶出的增加,绿豆清汤颜色加深,抗氧化能力上升。与自来水煮制相比,去离子水煮制所得豆汤中酚类物质含量及抗氧化活性较高;加入白砂糖或小苏打降低豆汤抗氧化能力,而加入食盐增加其抗氧化能力。绿豆清汤的b＊值与其抗氧化活性存在较强相关性。结论：酚类物质是绿豆清汤颜色及抗氧化能力的主要来源,并对豆汤pH值产生影响。使用弱酸性水煮制有利于得到颜色偏绿、抗氧化活性更强的绿豆清汤。