Cereal Chem. 73 (1):63-68 |
Comparison of In Vitro and In Vivo Measures of Resistant Starch in Selected Grain Products.
Judith A. Marlett (1) and Melissa J. Longacre (1). (1) Department of Nutritional Sciences, University of Wisconsin-Madison, 1415 Linden Drive, Madison, WI 53706-1571. Accepted October 13, 1995. Copyright 1996 by the American Association of Cereal Chemists, Inc.
The objectives of this research were to determine and compare resistant starch (RS) in typically consumed grain products using an in vivo animal model and two in vitro methods, and to determine the effect of processing for consumption on RS. Home-prepared cake, cookies, and muffins, and commercially processed white bread, corn cereal, and oat cereal were studied. Mean (± standard deviation, n = 6) RS content of these foods, determined using the colectomized rat, was 0.6 ± 0.1% (unprocessed) and 1.1 ± 0.7% (processed). Processing did not change RS in the two cereals. Starch remaining in the fiber residue was not similar to that in the in vivo measure of RS. In an in vitro system, developed to simulate gastrointestinal digestion, varying pancreatin (but not pepsin) treatment for 1-5 hr was required to obtain values comparable to those of the in vivo starch bioavailability. Low bacterial counts (approximately 20% of rat fecal concentration) in the ileal excreta and a continual monitoring of starch bioavailability from canned peas verified minimal microbial degradation of RS and indicated that the colectomized rat was a suitable model for RS studies. Our analyses suggest traditional grain products may provide 4-6 g of RS/day due to consumption levels.