Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: 4/27/1998
Publication Date: N/A
Technical Abstract: Undigested starch is a major contributor to gastrointestinal discomfort experienced from eating cooked dry beans (Phaseolus vulgaris L.). Plant breeders are interested in identifying genetic stocks of beans with highly digestible starch to use in food quality improvement programs. Before a selection program for starch digestibility can be initiated genetic variability must be ascertained. Breeding lines and cultivars from several dry bean market classes were evaluated for their starch digestibility using a laboratory procedure involving the determination of total dietary fiber with 3-enzymes. Grinding raw and cooked beans using a mill with the same size screen (either 40 or 60 mesh) resulted in larger particles in the raw than in the cooked bean sample and inflated the amount of indigestible starch in the raw bean samples. In an experiment in which cooked and raw beans were ground with different size sieves, we found that in order to obtain cooked and raw beans with comparable particle sizes (thus providing accuracy and reliability to indigestible starch determination), the cooked beans should be ground and sieved through a 40-mesh screen, and raw beans through a 60-mesh screen. Navy bean was the market class with the most digestible starch (10%). Black beans and kidney bean had the least digestible-starch >15%. Manteca, a Latin American market class with a pale yellow seed coat was similar in digestibility to navy beans. Although the evidence is anecdotal, Manteca beans are favored for their qualities of taste, texture, and good digestibility. The current research on indigestible starch appears to confirm the high digestibility, low flatulence attributes of Manteca bean.