Submitted to: Bean Improvement Cooperative Annual Report
Publication Type: Proceedings
Publication Acceptance Date: 3/1/1997
Publication Date: N/A
Citation: Interpretive Summary: Any material that is not digested and absorbed in the small intestine of humans is available for microbial fermentation in the colon. Large quantities of undigested food can cause cramps, diarrhea, and flatulence. Scientists believe that undigested starch is a major contributor to gastrointestinal discomfort experienced form eating cooked dry beans. Plant breeders are interested in identifying genetic stocks of beans with highly digestible starch to use in food quality improvement programs. Eighteen navy bean breeding lines were evaluated for their starch digestibility using a new laboratory procedure. The amount of indigestible starch found among the breeding lines ranged from 7 to 11 percent. This variability is useful to develop bean varieties with highly digestible starch through plant breeding. New bean varieties that are easy to digest may increase bean consumption in the USA. Industry benefits from more digestible and less flatulent beans through increased product sales.
Technical Abstract: Eighteen navy bean (Phaseolus vulgaris L.) Breeding lines were evaluated in duplicate for their indigestible starch levels by a total dietary fiber (TDF) assay. The sample residue obtained from TDF was used for the determination of resistant starch through solubilization with 2M KOH and digestion with glucoamylase. Indigestible starch ranged between 7 and 11%. Calculations of the standard deviation and coefficient of variation for each line showed that the laboratory methods were repeatable. The procedure is useful for screening bean germplasm for starch digestibility in breeding programs. There was no correlation between brine graniness from starch exuation of cooked beans and the amount of indigestible starch of the beans per se.