An intervention study was conducted to determine the in vivo digestibility of a commercial Type 4 resistant starch, namely, cross-linked phosphorylated (0.4% P) wheat starch (CLP wheat starch). Commercial unmodified (native) wheat starch was the negative control. Eleven ileostomy subjects participated in a randomized, double-blinded, cross-over design with a one-week washout period between test meals. Subjects consumed a plant-free breakfast including 26.8 g CLP wheat starch which was determined to contain 25.0 g of Prosky dietary fiber. The control breakfast included 26.9 g of commercial wheat starch. The subjects collected 2 h effluents over the next 24 h, and the wet effluents were assayed for total starch by AOAC Method 996.11. That assay was estimated to recover an average of 80.0% of the total starch in effluents when the subjects consumed CLP wheat starch. The in vivo level of RS in the commercial sample of raw CLP wheat starch (0.4% P) was determined to be 84.0%, whereas that of raw native wheat starch was 10.8%. The effective in vivo dietary fiber of CLP wheat starch was 89.0% compared to native wheat starch. When determining in vivo RS using the ileostomy model, if the origin of resistance to digestion in the starch is not robust, the Prosky assay will likely underestimate the ileal output of dietary fiber (RS).
- Cross-linked phosphorylated wheat starch
- In vitro Type 4 resistant starch
- In vivo Type 4 resistant starch
- Resistant starch (RS)