3种多酚复配对葵花籽脂氧合酶的协同抑制研究

Synergistic inhibition of sunflower seed lipoxygenase by a combination of three polyphenols

中文关键词:  葵花籽  脂质氧化  抗氧化剂  复配

英文关键词:sunflower seeds  lipid oxidation  antioxidants  combination

中文摘要:

      葵花籽富含不饱和脂肪酸，易因内源脂氧合酶（LOX）催化导致氧化酸败与风味劣变。因此，寻找高效、安全的天然内源酶抑制剂已成为研究热点。本研究旨在探索表儿茶素（EC）、表儿茶素没食子酸酯（ECG）和6-姜酚三种天然多酚复配物对LOX的抑制效果，筛选协同抑制LOX的最佳比例，并探究其抑制机制和在葵花籽仁贮藏中的应用效果。结果表明，当EC:ECG:6-姜酚的质量比为1:4:1时，对LOX的体外抑制率达到60.98%，半数抑制浓度为0.91 ± 0.001 mg/mL，抑制类型为可逆混合型抑制。通过荧光光谱、紫外-可见吸收光谱、红外光谱及显微形貌分析发现，多酚复配物通过非共价作用LOX的构象改变及微环境极性变化，从而有效抑制LOX活性。三种多酚复配显著降低了贮藏葵花籽仁的酸价、过氧化值及丙二醛含量，对体内LOX最高抑制率达31.97%，并有效抑制了硫化物及醛酮类异味物质的生成，显示了作为天然抗氧化剂的应用潜力。

英文摘要:

      Sunflower seeds are rich in unsaturated fatty acids and are prone to oxidative rancidity and flavor deterioration during storage due to the catalysis of endogenous lipoxygenase (LOX). Therefore, it has become a research hotspot in the field of food preservation to find efficient and safe natural endogenous enzyme inhibitors. In this study, epicatechin (EC), epicatechin gallate (ECG) and 6- gingerol were used as research objects to explore the LOX inhibitory activity of natural polyphenol complexes. Through a compounding strategy, the optimal ratio for synergistic inhibition of LOX was screened, and the inhibition mechanism, as well as the application effect during the storage of sunflower seed kernels, were investigated. Results showed that when the mass ratio of EC:ECG:6-gingerol was 1:4:1, the in vitro inhibition rate against LOX reached 60.98%, with a half-maximal inhibitory concentration of 0.91 ± 0.001 mg/mL, and its inhibition type was identified as reversible mixed-type inhibition. Fluorescence spectroscopy, ultraviolet-visible absorption spectroscopy, Fourier-transform infrared spectroscopy, and microscopic morphology analysis revealed that the combination of three polyphenols effectively inhibited LOX activity through non-covalent interactions, which induced conformational changes in the enzyme and altered the polarity of its microenvironment. The three-polyphenol combination significantly reduced the acid value, peroxide value, and malondialdehyde content of stored sunflower seed kernels, achieved a maximum inhibition rate of 31.97% against endogenous LOX in vivo, and effectively suppressed the formation of off-flavor compounds such as sulfides, aldehydes, and ketones, demonstrating its potential as a natural antioxidant.