Browning Prevention of Chips from Freshly Harvested Porang (Amorphophallus oncophyllus) Tubers through Immersion in Ascorbic Acid Solutions at Various Times

Abstract

Porang (Amorphophallus oncophillus) tubers contain multifunctional water-soluble heteropolysaccharides, called glucomannan. Therefore, the quality of porang tuber chips is highly depending on its glucomannan content and physical appearance. The presence of considerable amount of carotene, polyphenoloxidases and tannins in these tubers may cause browning of chips and flour during processing. The purpose of this research was to study the effect of anti-browning agent (ascorbic acid) concentrations (2, 5 and 7.5%) w/w) and immersion times (30, 60, 90, 120, 150 and 180 minutes) on the degree of whiteness of porang tuber chips. An increase in the concentration of anti-browning agent solution up to 5% w/w caused significant increase the degree of whiteness of porang tuber chips. However, further increase in the concentration of anti-browning agent solution exhibited reduction in the degree of whiteness of porang tuber chips. In addition, a longer immersion time also resulted in a higher degree of whiteness of porang tuber chips. The best browning prevention conditions were through immersion of porang tuber chips in 5% w/w ascorbic acid solution for 120 minutes, from which a highest degree of whiteness was achieved (79.41).