Hrncirik Karel, Fritsche Sonja
Unilever R&D Vlaardingen, Olivier van Noortlaan 120, 3133 AT Vlaardingen, The Netherlands.
J Agric Food Chem. 2005 Mar 23;53(6):2103-10. doi: 10.1021/jf048363w.
Three monovarietal extra virgin olive oils (EVOOs) were subjected to accelerated storage conditions (60 degrees C, dark) representative of the autoxidation process during shelf life. Oxidation markers, i.e., the peroxide value, conjugated dienes, the oil stability index, and minor components, were monitored. The changes in minor components, related to the stage of ongoing oxidation and expressed as a percentage of the induction period (IP), followed a similar pattern in all oils: o-diphenols diminished by the highest rate (halved within 15% of the IP), followed by alpha-tocopherol (halved within 35% of the IP). Carotenoids and chlorophylls were also affected by autoxidation, whereas squalene showed high stability (<20% loss within 100% of the IP). Polar phenols (especially o-diphenols) and alpha-tocopherol were deduced to be the most potent antioxidants of EVOO. They efficiently inhibited oxidative lipid deterioration and subsequent development of sensory defects (rancidity, discoloration), which occurred only after substantial depletion of these antioxidants. Therefore, they could also be used as markers for the oxidative status of EVOO particularly in the early stage of oxidation.
三种单一品种的特级初榨橄榄油（EVOOs）在代表保质期内自氧化过程的加速储存条件（60摄氏度，黑暗）下进行处理。监测了氧化指标，即过氧化值、共轭二烯、油脂稳定性指数和微量成分。与正在进行的氧化阶段相关并以诱导期（IP）的百分比表示的微量成分变化在所有油中遵循相似的模式：邻二酚减少速率最高（在IP的15%内减半），其次是α-生育酚（在IP的35%内减半）。类胡萝卜素和叶绿素也受到自氧化的影响，而角鲨烯表现出高稳定性（在IP的100%内损失<20%）。极性酚类（尤其是邻二酚）和α-生育酚被推断为EVOO中最有效的抗氧化剂。它们有效抑制了脂质氧化劣化以及随后感官缺陷（酸败、变色）的发展，这些缺陷仅在这些抗氧化剂大量消耗后才出现。因此，它们也可用作EVOO氧化状态的标志物，特别是在氧化的早期阶段。
