Analysis of Resistant Starches in Rat Cecal Contents Using Fourier Transform Infrared Photoacoustic Spectroscopy

Timothy James Anderson, Iowa State University
Yongfeng Ai, Iowa State University
Roger W. Jones, Iowa State University
Robert S. Houk, Iowa State University
Jay-lin Jane, Iowa State University
Yinsheng Zhao, Iowa State University
Diane F. Birt, Iowa State University
John F. McClelland, Iowa State University

Reprinted with permission from Journal of Agricultural and Food Chemistry 61 (2013): 1818, doi:10.1021/jf3042616.

Abstract

Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) qualitatively and quantitatively measured resistant starch (RS) in rat cecal contents. Fisher 344 rats were fed diets of 55% (w/w, dry basis) starch for 8 weeks. Cecal contents were collected from sacrificed rats. A corn starch control was compared against three RS diets. The RS diets were high-amylose corn starch (HA7), HA7 chemically modified with octenyl succinic anhydride, and stearic-acid-complexed HA7 starch. To calibrate the FTIR-PAS analysis, samples from each diet were analyzed using an enzymatic assay. A partial least-squares cross-validation plot generated from the enzymatic assay and FTIR-PAS spectral results for starch fit the ideal curve with a R2 of 0.997. A principal component analysis plot of components 1 and 2 showed that spectra from diets clustered significantly from each other. This study clearly showed that FTIR-PAS can accurately quantify starch content and identify the form of starch in complex matrices.