Improvement of Resistant Starch of Modified Uli Banana Flour prepared by Controlled Fermentation and Evaluation of Prebiotic Characteristics.

Abstract

Resistant starch (RS) type 3 (RS3) is potential as prebiotic source due to its physiological function. The objectives of this study were to increase the RS3 level of modified uli banana flour (MUBF) made by controlled fermentation of lactic acid bacteria (LAB) L. plantarum BSL on sliced uli banana with a concentration of 104 CFU/ml and 106 CFU/ml at various fermentation times (0, 6, 12 and 24 h) followed by autoclaving-cooling. Evaluation of the prebiotic properties of RS3 MUBF was performed by testing the viability of three probiotic candidates i.e. L. plantarum BSL, B. bifidum and L. acidophilus in media m-MRSB (MRSB without glucose) and aquadest. Both media contained 2.5% RS3 isolated from MUBF. The results showed that concentration of L.plantarum BSL and fermentation times affected the RS3 content of MUBF. Fermentation for 12h with inoculum concentration at 106 CFU/ml produced the highest RS3 content in MUBF (32.57%). RS3 either derived from controlled or spontaneous fermentation could support the growth of probiotics. Higher growth were observed for RS3 produced by controlled fermentation (2.09-2.53 log CFU/ml) compared to spontaneous fermentation (1.52-1.80 log CFU/ml). Synbiotic yoghurt made of 70% MUBF (as skim milk substitution) and probiotic either B. bifidum or L. plantarum BSL still contain a fairly stable probiotic (109 CFU/ml) during four weeks of storage at 4°C temperature. Sensory evaluation showed that panelists could accept the product for its attributes such as color, flavor, texture, consistency and taste.