Production of heat-stable, butyrogenic resistant starch

Butyrate formed by glucose fermentation in the large intestine is both a su bstrate of the energy metabolism and an important signal metabolite for col onocyte growth. Butyrogenic preparations with a content of 34-94% of resist ant starch type III (RS) were produced from 1,4-alpha-D-glucans with polyme r chainlengths of 10-35 glucose units, depending on the retrogradation cond itions. The procedure was optimized with respect to various parameters like temperature, polyglucan concentration in the gel, polymer chainlength dist ribution and fermentability. High concentrations and relatively high recrys tallization temperatures (about 25 degrees C) favor the formation of heat-s table 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, but yrate) 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.