Nutritional and functional properties changes during facultative submerged fermentation of gadung (Dioscorea hispida Dennst) tuber flour using Lactobacillus plantarum

This work aims to examine the influence of flour concentrations (5%-25% w/v), inoculum loading (2.5%-15% v/v), and fermentation time (0-144 h) on the nutritional and functional properties of gadung (Dioscorea hispida Dennst) tuber flour. The flour was microbiologically treated through facultative submerged fermentation using Lactobacillus plantarum. The carbohydrate, lipid, protein, fiber and ash contents were reduced by fermentation, while moisture content was increased. In general, the swelling power and the solubility of fermented flour were below those of the native flour. Carboxyl group content increased with fermentation time, whereas no clear trend was found for carbonyl group. The amylose content of the fermented flour was larger than that of the native flour, which most probably was due to the depolymerization of amylopectin branches to form new amylose-like molecules. The best fermentation conditions were flour concentration of 10% (w/v), inoculum loading of 5% (v/v), and fermentation for 48 h.