Study of Variation in Blanching Methods on Characteristics of Sweet Potato Leaves (Ipomoea batatas L) Erryana Martati (*), Dewi Shintawati
Department of Food Science and Biotechnology, Universitas Brawijaya, Jalan Veteran Malang Indonesia
*email: erryana_m[at]ub.ac.id
Abstract
Sweet potato leaves (Ipomoea batatas L.) were underutilised due to their short shelf life and low interest in consumption. Blanching is a thermal treatment usually performed before drying. The research aimed to study the effect of the variation method and pH of blanching on the physico-chemical characteristics of yellow sweet potato leaf powder. The experimental design used was a randomised group design with one treatment factor: blanching method and pH. Blanching method variations included no blanching, steam blanching, and hot water blanching with the pH at 5, 6, 7, 8, and 9. The characteristics of the leaf powder measured were the yield, moisture content, antioxidant activity, total phenolic content (TPC), and total flavonoid content (TFC). The test results showed that the treatments significantly affected the yellow sweet potato leaf powder^s antioxidant activity, TPC, TFC, colour, and yield. However, the treatments did not have a significant effect on moisture content. The best treatment determined by Zeleny^s multiple criteria decision-making method resulted a hot water blanching with pH of 8 was selected as the best treatment with the characteristics of yield 15.85 2.29%, L = 44.67 0.12, a = -2.20 0.38, b = +11.61 0.98, moisture content 2.09 0.04%, antioxidant activity 36.79 0.28%, TPC 22.47 0.85 mg GAE/g, and TFC 19.23 1.85 mg QE/g.
