Department of Pharmaceutical Sciences, Section of Food Science and Nutrition, University of Perugia, via San Costanzo, 06126 Perugia, Italy.
Institute of Food Science and Nutrition, Università Cattolica del Sacro Cuore, via Emilia Parmense 84, 29122 Piacenza, Italy.
Food Res Int. 2018 Mar;105:507-516. doi: 10.1016/j.foodres.2017.11.061. Epub 2017 Nov 26.
In this work, an Italian extra-virgin olive oil (EVOO) sample and the same sample added with a carotenoid-rich nutraceutical extract from Lycium barbarum L. (EVOOCar) were subjected to a frying process to comparatively assess chemical and physical changes and heat stability. Oxidation progress was monitored by measuring oil quality changes such as peroxide value, free acidity, K232, K268, and fatty acid composition as well as minor compound content, phenols, α-tocopherol, and carotenoids. An UHPLC/QTOF-MS metabolomics approach discriminated the two oil samples based on their chemical changes during frying, identifying also the phenolic classes most exposed to statistically significant variations. Partial least square discriminant analysis and volcano analysis were applied together to identify the most significant markers allowing group separation. The decrease in total phenolic content was lower in EVOOCar than in EVOO during frying. Monounsaturated and polyunsaturated fatty acids showed a significant percentage loss, 3.7% and 17.2%, respectively, in EVOO after 180min frying at 180°C, while they remained constant or slightly changed in EVOOCar. Zeaxanthin added to the oil rapidly decreased during the frying process. These findings showed that the addition of a carotenoid extract from L. barbarum can help to improve the oxidative stability of extra-virgin olive oil.
本工作以一种意大利特级初榨橄榄油（EVOO）样品和添加富含类胡萝卜素的枸杞营养提取物的同种样品（EVOOCar）为研究对象，进行了油炸过程对比，以评估化学和物理变化以及热稳定性。通过测量过氧化值、游离酸度、K232、K268 和脂肪酸组成以及微量化合物含量、酚类、α-生育酚和类胡萝卜素等油质变化来监测氧化进程。UHPLC/QTOF-MS 代谢组学方法根据油炸过程中化学变化对两种油样进行了区分，还确定了受统计显著变化影响最大的酚类化合物类别。偏最小二乘判别分析和火山分析一起应用于识别允许组分离的最显著标记物。在 180°C 油炸 180min 后，EVOOCar 中的总酚含量下降低于 EVOO，而单不饱和和多不饱和脂肪酸分别下降 3.7%和 17.2%，EVOOCar 中则保持不变或略有变化。添加到油中的玉米黄质在油炸过程中迅速减少。这些发现表明，添加枸杞类胡萝卜素提取物可以帮助提高特级初榨橄榄油的氧化稳定性。
