Effect of freezing and canning on the thiamine and riboflavin content in immature seeds of five cultivars of common bean (Phaseolus vulgaris L.)

The present work investigates thiamine and riboflavin content in the seeds of three cultivars of flageolet-type beans and two cultivars intended for dry-seed production. Seeds were collected at the milk-wax stage of maturity, characterized by a dry matter content of 40%. Seeds were analyzed raw, blanched, cooked and in three products prepared for consumption. These comprised ready-to-eat canned and sterilized beans and two frozen products, one obtained using the traditional method (blanching-freezing-frozen storage-cooking); and the other by means of a modified method (cooking-freezing-frozen storage-defrosting and heating in a microwave oven).Losses in thiamine and riboflavin content varied according to cultivar and were respectively within the following ranges, 70–82% and 48–68% in the traditional frozen product; 57–78% and 39–69% in the modified frozen product; and 78–87% and 54–77% in the sterilized product.

► Bean seeds collected at the milk-wax stage of maturity.
► Seeds raw, blanched, cooked and in three products prepared for consumption were investigated.
► Traditional method of freezing (blanching-freezing-frozen storage-cooking).
► Modified method of freezing (cooking-freezing-frozen storage-defrosting and heating in a microwave oven).
► Ready-to-eat canned and sterilized beans.