| Food-grade distarch phosphates containing resistant starch (RS) were prepared from 11 starches by reacting starch with a 99:1 (w/w) mixture of sodium trimetaphosphate (STMP) and sodium tripolyphosphate (STPP) in aqueous sodium hydroxide. The products belong in the RS4 category of RS, and gave up to 100% RS when assayed with the total dietary fiber method of the Association of Official Analytical Chemists (AOAC). The RS4 starches gelatinized in hot water, but gave low selling power (∼3 g/g) in excess water. Distarch phosphates also were prepared with medium swelling power (4--12 g/g) from six sources of starches by pre-swelling in alkali with salt, cross-linking with a 99:1 (w/w) mixture of STMP/STPP, purifying the product, and gelatinizing in hot water (95°C). The medium swelling distarch phosphates showed 5--60% RS. A medium swelling product made from wheat starch, after 6 cycles of swelling in hot water and oven drying, lost negligible mass and granule integrity. The RS4 starches could be distinguished from native starches by (1) an elevated phosphorus level, (2) insolubility (<1%) in 1 M KOH, (3) no pasting curve in the amylograph, and (4) increased temperature and decreased enthalpy of gelatinization measured by DSC. Hamsters fed 10% of low swelling RS4 Wheat starch compared to cellulose showed (1) less feed consumption and lower weight gain, (2) an increased blood level of high density lipoprotein cholesterol and a decreased level of very low and low density lipoprotein cholesterol, (3) a decreased level of liver cholesterol, and (4) an increased level of colonic short chain fatty acids, especially butyric acid. |
