烹调对蔬菜中总多酚和总黄酮含量的影响

以洋葱、芹菜、韭菜、菠菜、卷心菜和番茄为材料,采用福林酚试剂法和铝离子显色法分别测定经爆炒、焯、煮、微波4种方式处理后不同蔬菜中的总多酚及总黄酮含量,并以转移率、保存率和损失率为评价指标进行综合考察。结果显示:煮处理后,蔬菜中总多酚和总黄酮的含量明显下降,番茄中总多酚损失率高达42.14%,韭菜和菠菜的总黄酮损失率均超过40%;微波和焯处理后,蔬菜中多酚和黄酮向汤中的转移量较多,其中,微波处理后黄酮的转移率均超过35%;爆炒后蔬菜中的总多酚保存率相对较高,洋葱、韭菜、菠菜中总多酚损失率均低于10%。热烹调处理使蔬菜中部分黄酮和多酚发生降解,爆炒处理能最大限度地保留蔬菜中的多酚和黄酮。

Effects of cooking on content of total polyphenols and flavonoids in vegetables

To investigate the effect of various cooking methods on content of total polyphenol and flavonoids in vegetables, six kinds of vegetables, onion, celery, leek, spinach, cabbage and tomato, were respectively cooked by ways of quick–frying,blanching, boiling and microwave cooking. The total polyphenol content was determined by folin- ciocalteu method and total flavonoids by aluminum chloride chromogenic method. Indicators of the reserving rate, transferring rate and actual loss rate were employed to discuss the effect of different of cooking methods on polyphenols and flavonoids content. Results showed that the content of total polyphenols and flavonoids in vegetables decreased obviously with boiling, polyphenols loss in tomato was about 42.14%, and flavonoids loss in leek and in spinach were both above 40%. Polyphenols and flavonoids were partly transferred to soup after microwave cooking and blanch, the transferring rate of flavonoids were above 35%. The reserving rate of polyphenol remained high with quick–frying, there were less than 10% of polyphenols loss in onion, leek and spinach. Total polyphenols and flavonoids were declined after heat cooking, which might make them decomposed under high temperature. Polyphenols and flavonoids in vegetables could be kept to their maximum by quick–frying amongst the four approaches.