Behavior of antioxidants under some cooking conditions

本研究旨在阐明食品中抗氧化剂在烹饪条件下的行为。研究了两种香料，咖喱叶（九里香的叶）和姜。在110℃下，将干咖喱叶添加到含有10%亚油酸甲酯的底油中，仅添加0.1%的咖喱叶就足以延缓底油的氧化，表明咖喱叶在热烹调条件下具有抗氧化作用。用二氯甲烷提取咖喱叶，提取液经多次色谱分离，得到6个化合物，根据光谱学证据确定为咔唑类化合物。其中，三个化合物，其中每一个都有一个羟基的咔唑骨架上显示出较强的抗氧化活性。尤其是马哈尼碱，一个主要的咔唑，具有最强的能力，这促进了我们阐明其在热氧化的行为。在氧化过程中，马汉宁逐渐减少， 关于我们 .马哈宁耗尽后，立即进行的底物油的氧化从根本上。此外，没有检测到在氧化过程中显著增加的marhanine衍生物。这些事实表明，马哈宁在加热条件下是稳定的，并直接延缓了油脂的氧化。在生姜的情况下，[6]-姜辣素，生姜的主要抗氧化剂，在一些烹饪条件下的行为进行了研究。生姜压榨过40目筛后，其抗氧化能力和[6]-姜酚含量较压榨前降低约2/3。生姜在室温下放置24 h后，其抗氧化活性显著降低，而[6]-姜辣素的含量没有显著降低，这表明其他抗氧化剂的含量可能会降低。生姜末在加热3 min后，其抗氧化活性和[6]-姜辣素含量基本保持不变，说明[6]-姜辣素在短时间干煮后仍能保持稳定，发挥其抗氧化作用。少

This study was aimed to elucidate what behavior antioxidants from food showed under cooking condition. Two spices, curry leaves (the leaves of Murraya koenigii) and ginger were investigated. When dried curry leaves were added to the substrate oil including 10% methyl linoleate at 110℃, addition of only 0.1% of curry leaves was enough to delay oxidation of the substrate oil, which suggested that curry leaves could have antioxidant effect under heat-cooking condition. Curry leaves were extracted with dichloromethane and the extract was purified using repeated chromatographic techniques to isolate six compounds, which were determined to be carbazoles based on the spectroscopic evidences. Among them, three compounds each of which had a hydroxyl group on the carbazole skeleton showed a strong antioxidant activity. Especially mahanine, a major carbazole, had the strongest ability, which promoted us to elucidate its behavior under heat oxidation. During oxidation, mahanine gradually decreased … More . Immediately after mahanine was exhausted, oxidation of the substrate oil was progressed radically. Furthermore, there was no marhanine derivative detected which remarkably increased during oxidation. These facts suggested that mahanine was stable under heating condition and directly delayed oxidation of the oil. In the case of ginger, the behavior of [6]-gingerol, a major antioxidant of ginger, under some cooking conditions was investigated. The squeezed juice of ginger passing through 40 mesh possessed about two thirds of antioxidant capacity and [6]-gingeol contents compared with ginger before squeezing. When grated ginger was kept at room temperature for 24 hr, the antioxidant activity decreased significantly whereas [6]-gingerol content did not significantly decrease, which suggested that other antioxidants might decrease. When minced ginger was flied for 3 min, ginger maintained the antioxidant activity and [6]-gingerol content, which indicated that [6]-gingerol could be stable enough to exhibit its antioxidant effect after short dry cooking. Less