Effect of cultivar and roasting method on composition of roasted soybeans

BACKGROUND: The composition of raw soybeans and the roasting method have an important impact on the quality of roasted soybeans. The objective of the study was to determine the effect of food-grade soybean cultivars (IA 2064, IA 1008, IA 1008LF, Prairie Brand 299, Asgrow 2247) and roasting method (oil- and dry-roasting) on the composition of roasted soybeans. RESULTS: Moisture content decreased after roasting, with oil-roasted soybeans having a significantly lower moisture content than the dry-roasted soybeans. With the exception of the low linolenic acid cultivar (IA 2064), there were no significant differences in total lipid and fatty acid contents of the five cultivars. Oil-roasted soybeans had significantly higher lipid content than raw and dry-roasted soybeans owing to the absorption of oil. The soluble sugars and free amino acids contents of the five soybean cultivars were not significantly different. Decreases in the contents of free amino acids, but not soluble sugars, occurred during roasting. Greater reductions were seen in oil-roasted soybeans because of the higher roasting temperature. CONCLUSION: Roasting method, rather than cultivar, had the greatest effect on the composition of roasted soybeans. The food-grade soybean cultivars evaluated in this study were similar in composition. (C) 2009 Society of Chemical Industry