Enzymatic Modification of Corn Starch Influences Human Fecal Fermentation Profiles

Enzymatically modified starches have been widely used in food applications to develop new products, but information regarding digestion and fecal fermentation of these products is sparse. The objective of this study was to determine the fermentation properties of corn starch modified with α-amylase, amyloglucosidase, or cyclodextrin glycosyltransferase and the possible role of hydrolysis products. Samples differed in their digestibility and availability to be fermented by the microbiota, resulting in differences in microbial metabolites produced during in vitro fermentation. The presence or absence of hydrolysis products and gelatinization affected starch composition and subsequent metabolite production by the microbiota. Amyloglucosidase-treated starch led to the greatest production of short- and branched-chain fatty acid production by the microbiota. Results from this study could be taken into consideration to confirm the possible nutritional claims and potential health benefits of these starches as raw ingredients for food development.

Glycemic Response to Corn Starch Modified with Cyclodextrin Glycosyltransferase and its Relationship to Physical Properties

Corn starch was modified with cyclodextrin glycosyltransferase (CGTase) below the gelatinization temperature. The porous granules with or without CGTase hydrolysis products may be used as an alternative to modified corn starches in foods applications. The amount and type of hydrolysis products were determined, containing mainly β-cyclodextrin (CD), which will influence pasting behavior and glycemic response in mice. Irregular surface and small holes were observed by microscopic analysis and differences in pasting properties were observed in the presence of hydrolysis products. Postprandial blood glucose in mice fed gelatinized enzymatically modified starch peaked earlier than their ungelatinized counterparts. However, in ungelatinized enzymatically modified starches, the presence of β- CD may inhibit the orientation of amylases slowing hydrolysis, which may help to maintain lower blood glucose levels. Significant correlations were found between glycemic curves and viscosity pattern of starches.