Improvement of refined soybean oil by enrichment with phenolic extracts from wild and cultivated olive leaves

Background:: Several researches have focused on the antioxidant capacity of natural components extracted from plants. Their properties are determined by the presence of phenolic compounds that extend the shelf life of food and protect fats from autoxidation. Olive leaves, an abundant raw material, are a significant source of bioactive phenolic compounds, which can be used to enrich a widely used edible oil. Objective:: The goal of this study was to improve the properties and stability of soybean oil by adding phenolic compounds extracted from the leaves of wild and cultivated olive trees. Methods:: Leaf polyphenolic extracts obtained from Chemlal cultivar and wild olive were used to enrich refined soybean oil. The antioxidant activity was evaluated for chain-breaking antioxidant effect using DPPH and FRAP essay. The oxidative stability was estimated using a rancimat apparatus. The effect of the frying conditions was studied by determining the rate of the polar fraction. Results:: Total phenol contents from cultivated and wild olive leaves, were important: 1047.19mg EAG /100g and 1424.59mg EAG/100g, respectively. Oil extracts enriched with Chemlal and wild olive leaves extracts at 25ppm presented 93.29% and 93.20% inhibition percent of DPPH radical, respectively. An improvement of 75 and 73% was showed for oils enriched with Chemlal and wild olive leaves respectively for the antiradical activity against DPPH radical. The stability of the enriched oils is proportional to the concentrations of phenolic extracts and higher than that showed for the non-enriched one. The frying test showed that the enrichment is causing a complete absence of polar compounds in the fries. Conclusion:: The results of this study show the efficacy of adding polyphenols olive leaves to increase the quality and oxidative stability of refined soybean oil.

Physical properties and cookie-making performance of oleogels prepared with crude and refined soybean oil: a comparative study

The objective of this research was to fabricate crude soybean oil oleogels (CSO) using β-sitosterol (BS) and/or monoacylglycerol (MAG) and compare their role with that of refined soybean oil oleogels (RSO) in cookie making.