Production of heat-stable, butyrogenic resistant starch

Butyrate formed by glucose fermentation in the large intestine is both a substrate of the energy metabolism and an important signal metabolite for colonocyte growth. Butyrogenic preparations with a content of 34-94% of resistant starch type III (RS) were produced from 1,4-alpha-D-glucans with polymer chainlengths of 10-35 glucose units, depending on the retrogradation conditions. The procedure was optimized with respect to various parameters like temperature, polyglucan concentration in the gel, polymer chainlength distribution and fermentability. High concentrations and relatively high recrystallization temperatures (about 25 degrees C) favor the formation of heat-stable RS with T-o and T-p values >110 degrees C. The fermentation of these RS led to in vitro short-chain fatty acids levels (acetate, propionate, butyrate) of 2000-2500 mu mol/g faeces dry weight with butyrate contents of 30-60 mol%. Readily fermentable heat-stable RS, which can be used in various "functional foods", can be produced from poly-1,4-alpha-D-glucan of optimal chainlength. (C) 2000 Elsevier Science Ltd. All rights reserved.