Anthocyanins Content and Antioxidant Activity of Fresh Purple Fleshed Sweet Potato and Selected Products

Purple fleshed sweet potato is a potential source of anthocyanins which is as an antioxidant, antimutagenic, and anticarcinogenic. Anthocyanins can be damaged by high temperatures. However, traditionally a number of processed sweet potato products involve heat treatment. This study aimed to assess the reduction of anthocyanins content in processed sweet potato products (flour, chips, sweet potato, steamed, boiled, and fried pieces) from two types of local purple fleshed sweet potato (light purple and dark purple), therefore it might provide useful information stages in order to maintain the content of anthocyanins. The experiment was arranged in a Randomized Complete Block Design (RCBD) of factorial arrangement treatments (two types of purple fleshed sweet potato, and five types of purple fleshed sweet potato processed products). The main analysis parameter are anthocyanins content and antioxidant activity. The anthocyanins content of dark purple fleshed sweet potato was 61.85 mg/100g, 17 times higher than light purple fleshed sweet potatoes 3.51 mg/100g. Dark purple fleshed sweet potatoes have antioxidant activity approximately 59.25%, greater than light purple fleshed sweet potatoes 56.64%. Decrease in anthocyanins content for processed products from both types of purple sweet potatoes showed the same trend. Purple sweet potato processed products that able to maintain fairly high the content of anthocyanins (the lowest rate of decline in anthocyanin levels) were obtained on a steamed sweet potato (34.14% for dark purple and 42.16% for light purple), while the highest reduction obtained on the product chips (95.21% for dark purple and 88.47% for light purple). Reduction of antioxidant activity showed a directly proportion of the decrease in anthocyanins content of processed products, with the exception of processed products chips.