Wine industry generates a large amount of biowaste, such as grape marc and wine lees, which is considered in the Directive (EU) 2018/2001 as an adequate feedstock to produce advanced biofuels. Grapeseed oil fatty acid ethyl esters (FAEEs) can be obtained from oil extracted from grape marc and bioethanol distilled from wine lees or wine surplus. Although FAEE still has no specific standard, grapeseed oil FAEE would fulfill all of the properties set by the standard EN 14214, except oxidation stability. This work analyzes the effect of natural antioxidants on the oxidation stability of grapeseed oil FAEE, using grapeseed oil fatty acid methyl esters (FAMEs) as a reference for comparison. On the one hand, the biofuel, produced with conventional transesterification, was mixed with FAME and FAEE produced via in situ transesterification. On the other hand, antioxidants extracted from grapeseed or defatted grapeseed flour were added to the biofuel. The results show that (1) FAEE has worse oxidation stability than FAME, (2) in situ transesterification improves the oxidation stability, and (3) addition of natural antioxidants is hindered by their low solubility in alkyl esters. Finally, the concentration of antioxidants, measured by UV–vis spectroscopy, showed a correlation between the absorbance at 285 nm (characteristic of phenolic compounds) and the induction time (IT) of the samples.

中文翻译：

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氧化稳定性：葡萄酒行业废弃物开发完全可再生生物燃料的瓶颈。

葡萄酒行业会产生大量生物废料，例如葡萄渣和酒渣，在指令（EU）2018/2001中被认为是生产高级生物燃料的适当原料。葡萄籽油脂肪酸乙酯（FAEEs）可以从葡萄渣中提取的油和酒渣or或酒渣中蒸馏出的生物乙醇获得。尽管FAEE尚无特定标准，但葡萄籽油FAEE可以满足EN 14214标准设定的所有性能，但氧化稳定性除外。这项工作使用葡萄籽油脂肪酸甲酯（FAME）作为比较参考，分析了天然抗氧化剂对葡萄籽油FAEE氧化稳定性的影响。一方面，将通过常规酯交换反应生产的生物燃料与通过原位酯交换反应生产的FAME和FAEE混合。另一方面，从葡萄籽或脱脂葡萄籽粉中提取的抗氧化剂被添加到生物燃料中。结果表明：（1）FAEE的氧化稳定性比FAME差，（2）原位酯交换提高了氧化稳定性，（3）天然抗氧化剂在烷基酯中的溶解度低阻碍了其的添加。最后，通过紫外-可见光谱法测量的抗氧化剂浓度显示了在285 nm处的吸光度（酚类化合物的特征）与样品的诱导时间（IT）之间的相关性。（3）天然抗氧化剂在烷基酯中的低溶解性阻碍了它们的添加。最后，通过紫外-可见光谱法测量的抗氧化剂浓度显示了在285 nm处的吸光度（酚类化合物的特征）与样品的诱导时间（IT）之间的相关性。（3）天然抗氧化剂在烷基酯中的低溶解性阻碍了它们的添加。最后，通过紫外-可见光谱法测量的抗氧化剂浓度显示了在285 nm处的吸光度（酚类化合物的特征）与样品的诱导时间（IT）之间的相关性。