Change of the components and the activity of antioxidants in spices during cooking.

研究了生姜和高良姜在蒸煮过程中的稳定性和抗氧化剂的形成。生姜甲醇提取物在蒸煮4h后，其抗氧化活性没有下降，主要抗氧化成分(6)-、(8)-和(10)-姜酚的含量也没有变化。作为一种新的抗氧化剂，分离得到了两个(6)-姜二醇糖苷，并确定了其结构。此外，还观察了生姜丙酮粉粗酶体系中的内源性糖苷酶活性。(6)在具有清除亚油酸或DPPH自由基的模型体系中，姜二醇和其中一个糖苷表现出与(6)-姜酚相当的强抗氧化活性。已知其主要抗氧化化合物为1‘-乙酰氧基香草酚醋酸酯(ACA)，在大高良姜中可降解为1’-羟基香草酚醋酸酯(HCA)和对乙酰氧基肉桂醇(p-AC)。按高良姜皮、高良姜皮ACA主要分布在中央。研究发现，介质对ACA在蒸煮过程中的稳定性有很大影响。当在水中加入少量猪油时，ACA溶解在猪油中，并在烹饪过程中保持不降解。

The stability and the formation of antioxidants in ginger and greater galangal (Alpinia galanga) during cooking were investigated.The antioxidant activity of the methanol extract of ginger did not reduced by cooking for four hours, and the contents of (6)-, (8)- and (10)-gingerol, main antioxidant compounds of ginger, also did not change. As new antioxidant compounds, two glucosides of (6)-gingerdiol were isolated and the structures were decided. In addition, the endogenous glycosidase activity was observed in the crude enzymatic system with acetone powder from fresh ginger. (6)-Gingerdiol and one of the glucosides showed strong antioxidant activity corresponding to that of (6)-gingerol in the model system with linoleic acid or DPPH radical scavenging activity.It is known that the main antioxidant compound is 1'-acetoxychavicol acetate (ACA) and it is degraded to 1'-hydroxychavicol acetate (HCA) and p-acetoxycinnamyl alcohol (p-AC) in greater galangal. The content of these compound by part of galangal, peel, the center, germ and shoot, was determined. ACA was contained mainly in the center. It was found that the media gave great effect on the stability of ACA during cooking. When a little of lard was added to water, ACA was dissolved in lard and kept there without degradation during cooking.