A procedure to determine the germination period for optimum amylase activity in maize malt crude extracts for the artisanal production of maltose syrup from fresh cassava starch

Abstract

The study describes a timed colorimetric coupled enzyme assay for determination of amylase activity using starch as substrate. The method is simple for use by artisans to determine germination period for optimum amylase activity in maize malt crude extracts for maltose syrup production. The activity of amylase enzyme which released Glucose from standard starch solution is estimated by timing the decolourisation of standard acid permanganate solution by the released glucose. The germination period for optimum amylase activity in maize malt crude extracts from batches of Obaatanpa-Pokuase, Obaatanpa-Fumesua, Obaatanpa-MOFA, Mamaba and Golden Jubilee local maize having germinative capacities ≥ 90% were determined. Peak periods (P₁ and P₂) of amylase activity occurred; on germination days 4 and 9 for Obaatanpa-Pokuase, and 5 and 10 for the other varieties. Decolourisation rates at P₂ were 1.51 – 2.01 faster than at P₁ with Obaatanpa-MOFA having the fastest decolourisation rate at P₂. Obaatanpa-MOFA malt crude extract was subsequently used to process fresh Cassava (Esiaba var.) to brown maltose syrup with pH 4.60 – 5.30, 0.45% sulphate ash, DE 40%, and 33.4% water content. Syrup yield was 23.59% (mL/g wet starch) with a malty aroma and flavour.