Minimization of the oxidative rancidity in Sri Lankan traditional confectionery Dodol by addition of Vitamin E (alpha tocopherol) and determination of changes in peroxide value.

Abstract

Dodol is a popular traditional confectionery in Southeast Asia, containing a mixture of carbohydrates, proteins, and a high amount of fats. However, this high fat content makes Dodol susceptible to damage, such as rancidity due to oxidation reactions, impacting its shelf life. Typically, Dodol can only last for seven days in storage before deteriorating. This oxidative reaction leads to unpleasant odors and flavors, reduces food’s nutritional quality and color, and can potentially harm consumers' health due to the accumulated compounds. Determination of the Peroxide Value (POV) is the most generic method of measuring the oxidative stability of oils. One method to reduce this oxidative rancidity is addition of antioxidants, such as Vitamin E (alphatocopherol). In this study, Dodol samples were prepared by adding various concentrations of Vitamin E (alpha tocopherol) and the POVs were determined. Initial POVs in two commercial coconut oil samples were checked and they were 4.86 ± 0.00 meq/kg, 6.27± 0.05 meq/kg. Then three Dodol samples were prepared using the commercial coconut oil sample with least POV (4.86±0.00 meq/Kg). The control sample, a sample with 600mg of Vitamin E per 1L of coconut oil, and a sample with 1200mg of Vitamin E per 1L of coconut oil had POVs of 4.56±0.08 meq/Kg, 4.50±0.09 meq/Kg, and 4.46±0.05 meq/Kg, respectively, on the first day. By the seventh day, the POVs were 9.51±0.03 meq/Kg, 7.51±0.03 meq/Kg, and 5.08±0.08 meq/Kg, respectively. One-way ANOVA results revealed that there was no significant difference (P-value = 0.362 > 0.05) on day 1, but a significant difference (P-value = 0.00 < 0.05) on day 07 in POV between Dodol samples at a 95% significance level. Overall, as the quantity of Vitamin E increased, Dodol samples had lower POV, the sample containing 1200mg Vitamin E/1L coconut oil showing the most promising results (5.08±0.08 meq/Kg) on day 7. This suggests that using 1200mg of Vitamin E per 1L of coconut oil in Dodol manufacturing processes can enhance the shelf life of Dodol beyond seven days.