PARTIAL HYDROLYSIS OF PURPLE SWEET POTATO FLOUR BY AMYLASE FROM Saccharomycopsis fibuligera AND ITS APPLICATION FOR COMPOSITE BREADMAKING

Abstract

Purple sweet potato is one of underutilized carbohydrate sources in Indonesia, whilst known as good source of carbohydrate and can act as functional food due to its anthocyanine and dietary fiber contents. Therefore in the present study, we try to modify the sweet potato flour by partial hydrolysis using amylase produced by Saccharomycospsis fibuligera R64 and apply the partially hydrolyzed flour for composite breadmaking. The amylase was produced using batch method and partially purified by the addition of ammonium sulfate followed by gel filtration chromatography on Sephadex G25 using fast performance liquid chromatography system. The enzyme was then used to hydrolyze the purple sweet potato flour. Characterizations of the partially hydrolyzed flour comprise reduction in amylose-iodine complex, SEM and XRD. Partially hydrolyzed flour was then used as composite flour for bread, with ratio of wheat to partially hydrolyzed purple sweet potato flour was 70 : 30. The produced bread was then analyzed for its texture, organoleptic test and visualization of the bread crumb using TEM. The results of the present study indicate that the enzyme partially hydrolyzed the sweet potato flour. Even though the quality of the composite bread is not as good as wheat bread, partial hydrolysis seems to improve the texture and appearance of the composite bread, as indicated by better swelling volume and firmness of the composite bread using partially hydrolyzed purple sweet potato flour.