Oxidative stability of biodiesel blends derived from different fatty materials

• Only pure biodiesels from pequi and maize presented an induction period superior to that established by EN 14214.
• Corn biodiesel promoted a significant increase in the induction period of soybean biodiesel.
• Swine fat biodiesel promoted decrease in the induction period of additive biodiesel.
• Vegetable oils sources rich in antioxidants ensured an improvement in the oxidative stability.

The use of biofuels in recent years, in particular the biodiesel has attracted various studies in order to mitigate some of the problems related to their negative points, such as its high susceptibility to oxidation. In this context, this study aims at assessing the effect of blending biodiesels derived from different sources with soybean (Glycine max L.) biodiesel on its oxidative stability. In order to conduct the experiment a 23 factorial design and blended soybean biodiesels were used at different levels with corn (Zea mays L.), pequi (Caryocar brasiliense Camb.) and swine (Sus scrofa domesticus) fat biodiesels, which were obtained by means of alkaline homogeneous transesterification. Oxidative stability was evaluated (induction period), acidity index, peroxide index and specific weight. Based on the statistical results obtained, it was concluded that the blending of soybean biodiesel with biodiesels derived from different fatty materials causes variations in its oxidation stability. The addition of esters derived from vegetable sources ensured improvement in the oxidative stability, whereas swine fat esters provided a decline in the induction period responses obtained from their blending with soybean biodiesel.