Influence of hydrogenation and antioxidants on the stability of soybean oil biodiesels.

This study examined the influence of hydrogenation and antioxidant activity of natural products derived from Mangifera indica on soybean biodiesel stability. Biodiesels were prepared with refined, semi-refined, and partially hydrogenated soybean oil and the stability was evaluated in a Rancimat apparatus. The biodiesel from partially hydrogenated soybean oil showed greater stability (11.9h), exceeding the standard limit established by the Brazilian National Petroleum Agency (6h). Gallic acid, tannic acid, and mango seed kernel extract were evaluated as antioxidants. The gallic acid showed higher antioxidant ability than the other products, increasing twofold the oxidative stability (20.8h). The results indicate the importance of mango seed as a source of efficient antioxidants for biodiesel just like gallic acid. Practical applications: The results provide detailed information about: (i) the influence of hydrogenation on soybean biodiesel stability; (ii) the antioxidant activity of natural products derived from M. indica; (iii) and the importance of each phenolic constituent on the stability. Mango seed is an abundant waste product from fruit juice industry in Brazil and could be used for obtaining an effective antioxidant additive for biodiesel.