Correlation of physio-chemical characteristics in the seed coat and canning quality in different dark red kidney bean (Phaseolus vulgaris l.) cultivars

Abstract

The canned kidney bean (Phaseolus vulgaris L.) is one of the major consumption forms of this agricultural product. In the canning industry, seed coat splitting is considered one factor affecting the integrity of the appearance in the final product. Three different dark red kidney bean cultivars (85, 453 and Nickols) grown in the Wisconsin area were studied in this research. The physiochemical properties in this study included moisture content, the seed coat to whole seed weight ratio, the weight per seed, ash, mineral (sodium, calcium, iron, potassium and magnesium) and total crude protein content in the seed coat. The correlations of these properties with the seed coat splits were investigated. In the canned product, highly significant differences (P<0.01) in percentage of split seed coat were found among the three cultivars studied. Canned cv. 85 had significantly fewer seed coat splits than the other two cultivars. Cv. 85 was significantly higher in moisture content, as well as ash, sodium, calcium and iron content in the seed coat. The seed coat of cv. 453 was significantly higher in magnesium, and total crude protein. Cv. Nickols was found to be significantly higher in the weight per bean and seed coat splits after the canning process. Significant negative correlations were found between the percentage of seed coat splits, sodium (r = -0.89, p< 0.01), calcium (r = -0.74, P< 0.01) and iron content (r = -0.79, P< 0.05) in the seed coat. A positive correlation was found between sodium content and calcium content (r = 0.69, P< 0.05) in the seed coat. Increased calcium content in the seed coat was accompanied with increased sodium content. A significant positive relationship (r = 0.901, P< 0.01) was found between seed weight and the percentage of seed coat splits. This research suggested that several physiochemical factors of the seed coat, including weight per seed, sodium, calcium, and iron content, might play important roles in the integrity of the seed coat during the thermal processing.