Department of Soil, Plant and Food Sciences, Food Science and Technology Unit, University of Bari Aldo Moro, Via Amendola, 165/A, Bari I-70126, Italy.
Department of Soil, Plant and Food Sciences, Food Science and Technology Unit, University of Bari Aldo Moro, Via Amendola, 165/A, Bari I-70126, Italy.
Food Res Int. 2018 Jun;108:48-56. doi: 10.1016/j.foodres.2018.03.034. Epub 2018 Mar 12.
Olive leaves are a waste of the olive oil processing industry and represent a good source of phenolic compounds. The aim of this work was to assess the influence of olive leaf extract (OLE) on lipid oxidation of baked snacks, like breadsticks, made with wheat flour, extra virgin olive oil (EVO), white wine, and salt. Two EVOs having different peroxide value and antioxidant profile (total phenol content, tocopherols, carotenoids, and antioxidant activity) were considered. The snacks were subjected to oven test or stored in the usual conditions of retailer shelves. The obtained data highlighted that EVO plays a key role both for the quality and for the shelf-life of baked snacks and the use of OLE is recommended especially when baked snacks are produced with low quality EVO which therefore does not have a good content of natural antioxidants. The OLE addition significantly reduced the forced oxidative degradation during oven test, as evidenced by a decrease of 27% in oxidation-related volatile compounds and of 42% in triacylglycerol oligopolymers compared to control snacks (CTR) without OLE. Moreover, OLE effectively acted also in normal storage conditions, improving sensory data, induction times, antioxidant activity, and volatile compounds compared to CTR (i.e. hexanal 165.49 vs 38.31 μg g in OLE-added). The amount of oxidation-related volatile compounds showed an opposite trend with the quality level of oil used.
橄榄叶是橄榄油加工行业的废弃物，却是酚类化合物的良好来源。本研究旨在评估橄榄叶提取物（OLE）对用小麦粉、特级初榨橄榄油（EVO）、白葡萄酒和盐制成的烘焙小吃（如面包棒）的脂质氧化的影响。考虑了两种具有不同过氧化物值和抗氧化特性（总酚含量、生育酚、类胡萝卜素和抗氧化活性）的 EVO。将小吃进行烤箱测试或在零售商货架的常规条件下储存。所得数据表明，EVO 对烘焙小吃的质量和保质期起着关键作用，建议使用 OLE，特别是在使用低质量 EVO 生产烘焙小吃时，因为低质量 EVO 没有足够的天然抗氧化剂。与不含 OLE 的对照小吃（CTR）相比，OLE 显著降低了烤箱测试期间的强制氧化降解，这表现在氧化相关挥发性化合物减少了 27%，三酰基甘油低聚物减少了 42%。此外，OLE 还在正常储存条件下有效发挥作用，与 CTR 相比，改善了感官数据、诱导时间、抗氧化活性和挥发性化合物（例如，加入 OLE 的己醛为 165.49μg/g，而 CTR 为 38.31μg/g）。与所用油的质量水平相反，氧化相关挥发性化合物的量呈现出相反的趋势。
