The effect of antioxidant additives on the characteristics of food-grade grease using castor oil (Ricinus communis L.) as the base oil

Grease has three basic components: base oil, thickening agents, and additives. Castor oil has a potential role as a lubricant base oil in grease, but it has lower oxidative stability than mineral oil. Antioxidant additives can delay oxidation reactions in food-grade grease. Li-12-hydroxystearate soap is used as a thickening agent. The food-grade grease is formulated via saponification, dilution, recrystallization, and homogenization. This research aimed to study the effects of different types (BHT, TBHQ, and high molecular weight phenolic) and concentrations (0%, 0.5%, 1%, 1.5%, and 2%) of antioxidants on food-grade grease characteristics. Several characteristics of greases, such as dropping point, pH, consistency, and corrosion resistance were observed. The results showed that different antioxidants induced differences in dropping points, and different antioxidant concentrations induced differences in dropping points and consistency. The best performance was obtained from food-grade grease formulated with high molecular weight phenolic antioxidant. This had the following characteristics: dropping point 193 °C, pH 7, consistency NLGI 2, and corrosion resistance group 1a.