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Functionality of enzymatically treated corn starches above gelatinization temperature

Abstract:

Starch is the major component in the human diet and has also unique functionality that has permitted its wide use in food products and industrial applications. In its native form, does not always fulfill the requirements for certain types of processing. However, enzymatic modification can be an alternative method to meet the specific needs of industrial processes. The aim of this study was to evaluate the effect of two different enzymes, fungal α-amylase (AM) and amyloglucosidase (AMG), on corn starch above gelatinization temperature, with special emphasis on biochemical features and structural analyses of treated starches. Amylase decreased significantly the peak viscosity of the starch, whereas amyloglucosidase reduced the final viscosity and setback. Functional properties of starch are directly influenced by hydrothermal (heat and moisture) treatment or processing conditions. Differences were observed among hydration properties. Specifically, AMG activity has more influence breaking the degree of association between intermolecular bonds, and more soluble compounds are leached out. It was also found through scanning electron microscopy that the gel structure displayed as a network matrix was highly perforated with big cell pores and thick walls when treated with AM, and some elongated structures from gelatinized starch were observed in the AMG treated starch.