Saccharification of unripe banana flour using microwave assisted starch degrading enzyme hydrolysis for development of wine and vinegar fermentations

Abstract

Unripe banana flour (UBF) from Musa (ABB) ‘Kluai Namwa’ was used as the substrate for sugar syrup production by microwave assisted starch degrading enzyme hydrolysis. Results showed that a concentration of 300 g/L of UBF subjected to 800 W microwave power for 2.0 min, with subsequent hydrolysis by a low temperature amylase (iKnowZyme® LTAA) and glucoamylase (iKnowZyme® GA) at 50°C for 9 h yielded highest sugar syrup production at 20 ± 0.89 °Brix of total soluble solids (TSS). The major hydrolysis product from UBF determined by thin-layer chromatography (TLC) was glucose, with reduced amounts of maltose and maltotriose. Fermentation by mixed strains of Saccharomyces cerevisiae produced alcohol content at 13.2 ± 0.07% (w/v) after 10 d at room temperature. Acetic acid fermentation achieved using Acetobacter aceti TISTR 354 by surface culture fermentation (SCF) in a stainless-steel tray chamber yielded 5.10 ± 0.12% (v/v) after cultivation at room temperature for 9 d, corresponding to standard commercial vinegar products at over 4.0%. This is the first report detailing production of sugar syrup, wine, and vinegar from UBF, using microwave assisted starch degrading enzyme hydrolysis at 50°C. Results showed that producing an alternative healthy products from natural material could be feasible with added value through biotechnological processes.