Cleaning and Total Glycoalkaloid Reduction in `Great Northern' Beans

Abstract

Nightshades (Solanum spp.) are weeds that result in production losses of dry beans (Phaseolus vulgaris) due to interference and to staining of beans with nightshade berry juice at harvest. A method of cleaning beans stained with the juice of nightshade berries was developed. The method involved fluidizing the beans and gently abrading surface soil from the seedcoat. The beans were analyzed for total glycoalkaloid content, color, and suitability for processing. The total glycoalkaloid content was reduced from 26 mg/100 g to undetectable levels by cleaning. The cleaned beans had higher total light reflectance than unstained beans, but did not differ in Hunter Lab `a' or `b' values. Cleaned beans were not significantly different from unstained beans in quality when processed.