Analysis of Cereal Starches by High-Performance Size Exclusion Chromatography
Starch has unique physicochemical characteristics among carbohydrates. Two important characteristics of starch are amylose/amylopectin ratio and molecular weight. The objective of this study was to develop a simple, one-step, and accurate method for the determination of amylose/amylopectin ratio and weight-averaged molecular weights of starch in whole meal cereal samples. This method would allow for the simultaneous measurement of these important properties without the time-consuming step of large-scale starch extraction. Starch from spring wheat, barley, oat, rye, buckwheat, rice, durum wheat, and corn was precipitated with ethanol and solubilized with potassium hydroxide and urea before analysis by a high-performance size exclusion chromatography (HPSEC) system with a refractive index detector. To verify peak identity, fractions were collected and then gas chromatography analysis of soluble starch and beta-glucan assays was performed. All HPSEC fractions contained only glucose and no beta-glucan was detected, indicating that there was no contamination from non-starch polysaccharides. Weight-averaged molecular weights were calculated using a series of gel permeation chromatography grade dextrans. The method described in this study can be used to determine amylose/amylopectin ratio and weight-averaged molecular weight of cereal starches using as low as 25 mg whole meal samples without large-scale starch extraction.
KeywordsStarch High-performance size exclusion chromatography Cereal Amylose Amylopectin
High-performance size exclusion chromatography
This work was supported by North Dakota State University Agricultural Experiment Station and a grant from the North Dakota Wheat Commission. We would like to thank Drs. Douglas Doehlert and Shahryar Kianian for providing durum waxy flours and to Angela Ostenson for her help in the analysis of the starch samples. We are grateful to the personnel at the Agricultural Experimental Station, North Dakota State University for providing other cereal samples.
- American Association of Cereal Chemists (2000) Approved methods of the American Association of Cereal Chemists. AACC International, St. PaulGoogle Scholar
- Dimler RJ, Davis HA, Rist CE, Hilbert GE (1944) Cereal Chem 21:430Google Scholar
- Eliasson AC, Gudmundsson M, Svensson G (1995) Food Sci Technol 28:227–235Google Scholar
- Jane J, Shen L, Chen J, Lim S, Kasemsuwan T, Nip WK (1992) Cereal Chem 69:528–535Google Scholar
- Mccleary BV, Nurthen E (1986) J Inst Brew 92:168–173Google Scholar
- Ohm J, Ostenson AM, Hareland GA, Doehlert DC, Simsek S (2008) Cereal Foods World 53:71AGoogle Scholar
- Robyt JF (2008) Glycoscience. Springer, BerlinGoogle Scholar
- Seguchi M, Higasa T, Mori T (1994) Cereal Chem 71:636–639Google Scholar
- Tester RF, Karkalas J (1996) Cereal Chem 73:271–277Google Scholar
- Whistler RL, BeMiller JN (2007) Carbohydrate chemistry for food scientists. AACC International, St. PaulGoogle Scholar
- Wu YV, Doehlert DC (2002) Food Sci Technol 35:30–33Google Scholar