Enzymatic production of malto-oligosaccharide in potato by freeze-thaw infusion

Freeze-thaw infusion (FI) is a technique used to rapidly impregnate food materials with enzymes. We investigated whether an enzyme could penetrate both the intercellular spaces and the intracellular spaces using FI by determining the enzymatic potato starch decomposition efficiency and by assessing maltooligosaccharide production. Malto-oligosaccharide production by FI using α-amylase was dependent on time and enzyme concentration, reaching a maximum production of 6.5 g/100 g after 60 min at 1.0% (w/v) enzyme. This corresponds to an enzymatic decomposition efficiency of 76%, compared with crushed potatoes (8.5 g/100 g). Production after infusion or immersion of unfrozen potatoes was below 1.0 g/100 g and production after immersion of freeze-thawed potatoes was 3.0 g/100 g. The results indicate that FI enables efficient intracellular impregnation, which allows for efficient enzymatic decomposition of intracellular substrates, while retaining food material shape.