Sugar syrup production from oat starch by enzymatic conversion method

This thesis describes the enzymatic conversion of oat starch to maltose and glucose by amyloglucosidase and pullulanase. Starch was isolated from oat with three different extraction methods as water (WS), alkali (AS), and alkali-acid (ALAS). Ultrasound (US) pretreatment for 30 (US30), 45 (US45), 60 (US60) and 75 min (US75) in water extraction method was also studied. The highest extraction yield was found as 54.03% by the alkali-acid method. The highest gelatinization enthalpy value was found in the US 60 as 13.65 J/g and the lowest as 7.30 J/g in the alkali method. Ultrasound treatments decreased the gelatinization temperature ranges and increased the gelatinization enthalpy values. Enzymatic starch hydrolysis was carried out for 10%, 12.5% and 15% starch solutions obtained by water, alkaline and acid-alkali methods. Increasing starch slurry concentration decreased the required times for liquefaction which were 30, 27 and 24 minutes for 10%, 12.5% and 15% starch solutions, respectively. 72 sets of saccharification were performed by amyloglucosidase and pullulanase enzymes. When the concentration of the starch solution increased, the amount of maltose decreased in WS and AS for all enzyme concentrations studied. Whereas for ALAS, the maximum maltose formation was observed in 12.5% starch solution. The highest glucose (% 58.10) production was obtained for 10% ALAS with use of both amyloglucosidase and pullulanase whereas highest maltose formation (% 105.15) was obtained for 10% WS. The highest dextrose equivalents (DE) as 99.13 were found for 10% ALAS with use of maximum amount of pullulanase. We can conclude that, oat starch can be used as alternative starch source for sugar syrup production.