Effect of Pullulanase Debranching and Retrogradation on Resistant Starch Yield and Glycemic Index of Garri

Abstract

Aims: This research is aimed at developing a method of processing to increase the quantity of resistant starch in garri and reduce its glycemic index using pullulanase-producing Bacillus subtilis organism. Place and Duration of Study: Department of applied microbiology and brewing, Nnnamdi Azikiwe University, Awka between January, 2018 and February, 2019. Methodology: The organism was isolated from different cassava processing sites in Anambra metropolis, Nigeria. It was then identified based on phenotypic, biochemical and molecular characteristics After which the pullulanase assay, the fermentation studies, resistant starch analysis and glycemic index was analysed. Results: Pullulanase assay result showed Bacillus subtilis as a very good pullulanase producing organism with a pullulanase quantity of. The resistant starch content was found to be higher for the samples fermented with the choice organism and retrograded at 10oC at 14.29%, than the control garri sample fermented without any organism and not retrograded at 4.73%. The glycemic index was relatively high in all the garri samples, however, the lowest glycemic index, 62% was observed in the garri sample produced with the choice organism. Conclusion: This research has been able to show that pullulanase enzyme from Bacillus subtilis is a very useful industrial raw material in production of functional foods with low glycemic index.