Submitted to: American Journal of Food Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 18, 2006
Publication Date: March 26, 2007
Citation: Stevenson, D.G., Eller, F.J., Jane, J., Inglett, G.E. 2007. Starch structures and physicochemical properties of a novel beta-glucan-enriched oat hydrocolloid product with and without supercritical carbon dioxide extraction. American Journal of Food Technology. 2(4):248-256. Interpretive Summary: Properties of C-trim30, a beta-glucan enriched oat hydrocolloid with 32% beta-glucan content, was studied with and without lipids removed by supercritical carbon dioxide. C-trim30 consisted of porous particles, had extremely high paste viscosity, and water retention that was further increased by lipid removal. Amylopectin fraction of starch in C-trim30 had been degraded in size by eight times but amylopectins were still very large, creating opportunity to further enrich beta-glucan content by starch degradation. Study showed that C-trim30 possessed desirable properties to act as a fat substitute and thereby help combat many diet-related health disorders such as obesity, cardiovascular disease, and diabetes.
Technical Abstract: Structures and physicochemical properties of C-trim30, a beta-glucan-enriched oat product (32% beta-glucan), with or without supercritical carbon dioxide (SCD) extraction were studied. Scanning electron micrographs showed C-trim30 was composed of 200-300 mm long particles, with large pores. High-performance size-exclusion chromatography equipped with multi-angle laser-light scattering and refractive index detectors showed C-trim30 had three peaks, corresponding to amylopectin with weight-average molecular weight (Mw) of 1.0 x 10**8, breakdown amylopectin product (Mw 1.1 x 10**7) and amylose (Mw 1.7 x 10**6). C-trim30 amylopectin Mw and gyration radii increased after SCD extraction suggesting aggregation of molecules occurred. No thermal transitions were observed for C-trim30 heated 0-150 deg C measured using differential scanning calorimeter. C-trim30 pasting properties, measured using Rapid Visco Analyser, showed high peak viscosity (291 RVU) at starting test temperature (30 deg C), high breakdown (200 RVU), final (273 RVU), and setback (183 RVU) viscosity for 8%(w/w) suspension in water. SCD extraction increased all pasting parameters, especially peak (423 RVU), and breakdown (318 RVU) viscosity. Thermogravimetric analysis of C-trim30 heated from 15 deg C to 110 deg C showed higher water-holding capacity occurred without SCD extraction throughout entire temperature range. Study showed C-trim30 with and without SCD extraction are beneficial oat hydrocolloidal ingredients that could function as fat substitutes.