The utilization of cocoa polyphenol extract to improve the shelf life of bulk frying oil used in open and deep frying

Bulk Frying Oil (BFO) derived from semi-purified crude palm oil is widely used in Indonesia. Different from refined-bleached-deodorized palm olein that usually undergo full purification and fractionation, BFO is considered as lower quality because it still contains soft stearin fraction. Long shelf life and the reusability of frying oil could be improved by the addition of synthetic antioxidant such as BHA (butylated-hydroxyanisole), BHT (butylated-hydroxytoluene) and TBHQ (tertiary-butyl-hydroquinone). However, synthetic antioxidants utilization is being replaced with natural compound due to the rising health concerns. Polyphenol is a natural antioxidant which is commonly found in cocoa bean and had reported to exhibit an ability to retard lipid oxidation. This research was aimed to study the effect of polyphenol extracted from unfermented cocoa bean to extend shelf life and reusability of bulk frying oil. Central Composite Design of Response Surface Methodology was used to study the effects of polyphenol concentration and frying frequency in open and deep frying of soybean tofu. Results showed that the addition of polyphenol extract was able to retard the formation of free fatty acids and peroxide value during frying process and maintain the clarity of the oil. The optimization study revealed that the addition of 0.04% polyphenol extract could prolong the usage of oil up to 8 times when utilized in open frying. On the other hand, only 0.01% of polyphenol extract is needed to prolong the oil usage up to 20 times when it was applied in deep frying method.