Pengaruh Metode Perlakuan Awal (Pre-treatment) dan Suhu Pengeringan terhadap Mutu Fisik, Kimia, dan Fungsional Tepung Ubi Jalar Ungu

Abstract

The purpose of this research was to find the effect of pre-treatment method and drying temperature on physical, chemical, and functional of purple flesh sweet potato flour. This research was using randomized design with two factors, namely the method of pre-treatment (P): (sweet potato unpeeled and sliced, sweet potato peeled and sliced, sweet potato unpeeled then sliced and soaking in 0,5% sodium metabisulfite (Na2S2O5), sweet potato peeled then sliced and soaking in 0,5% sodium metabisulfite (Na2S2O5) and the drying temperature (T): (50 oC, 55 oC, 60 oC, 65 oC). The parameters analyzed were the color values, bulk density, organoleptic test of color and aroma, browning index, moisture content, and water and oil absorption, swelling power, solubility, and baking expansion. The results showed that the pre-treatment had highly significant effect on the value of the color, moisture content and antocianin, had no significant effect on bulk density, organoleptic test of color and aroma browning index, water absorption, absorption of oil, swelling power, solubility, and baking expansion. The temperature of drying had highly significant effect on the bulk density, organoleptic test of color and aroma, had no significant effect on the value of the color, browning index, antocianin, water and oil absorption, swelling power, solubility, and baking expansion. The interaction between the two factors had significant effect on moisture content and had no significant effect on the value of the color, bulk density, organoleptic test of color and aroma, browning index, water and oil absorption, swelling power, solubility, and baking expansion. The flour with the best quality was using pre-treatment of peeled tuber and soaking in 0,5% sodium metabisulfite (Na2S2O5) and the drying temperature of 65 °C. Ash content, protein content, fat content, crude fiber content, starch content, amylose and amylopectin, total sugar, reducing sugar, dextrose equivalent, and the degree of polymerization of the best flour were analyzed.