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  1. Apr 2020
    1. In the first of two enzymatic steps that produce high-glucose syrup as an intermediate to high-fructose syrup and other products, bacterial α-amylase is employed at pH 6–7 and about 105°C to hydrolyze starch purified by wet milling to roughly DE (dextrose equivalent) 10, DE being the percent of reducing end-groups in the aqueous sugar mixture relative to those in pure glucose of the same concentration. This indicates that the average maltooligosaccharide produced has a DP (degree of polymerization) of 10, although the mixture has a very wide DP range. DE 30 or more can be attained if the reaction proceeds to completion, but DE 10 is chosen to minimize the probability of pseudo-crystallization at lower DEs and the extent of alkaline-catalyzed isomerization of the reducing-end glucosyl residue at higher DEs.In the second step, at pH 4.3–4.5 and roughly 60°C, fungal glucoamylase and a small amount of pullulanase (pullulan 6-glucanohydrolase, EC, the latter used to rapidly hydrolyze the α-1,6 bonds from the original starch feed, convert the maltooligosaccharide mixture to approximately 96% glucose (dry basis). The remainder is composed of byproducts from α-amylase hydrolysis plus mainly isomaltose [α-glucopyranosyl-(1,6)-glucose] and isomaltotriose from the glucoamylase-catalyzed condensation of glucose.

      If I'm understanding this correctly, all I need is alpha amylase (easily obtainable) and beta amylase (AKA glucoamylase, also obtainable). When buying these, I've found that alpha amylase is advertised as simply amylase, whereas beta amylaze is advertised as glucoamylase

      This mentions both pH and temperature, but fails to mention time. I'd expect it only takes a matter of hours (or less).