Hard‐to‐cook phenomenon in beans: Changes in antinutrient factors and nitrogenous compounds during storage

Abstract

Five different bean varieties (Phaseolus vulgaris) from Kenya, which were either freshly collected or stored for 5 years in tropical conditions (30-40°C; > 75% humidity), were compared for their cooking characteristics. The beans under storage develop an irreversible phenomenon classified as 'hard-to-cook' (HTC) which results in undesirable characteristics limiting their acceptability. Our aims were to determine the effects of the HTC phenomenon on the proteins and antinutrient factors in these beans. Both fresh and HTC beans contained nutritionally significant amounts of lectins, trypsin and a-amylase inhibitors. HTC samples had higher lectin and lower a-amylase inhibitor contents, while the amounts of trypsin and chymotrypsin inhibitors were the same. Storage appeared to reduce waterextractable nitrogen. Fractionation with sodium dodecyl sulphate also showed that less protein may be available in HTC than fresh beans. We established that the undesirable changes in beans, such as increased cooking time, which often accompany the storage of harvested seeds under tropical conditions produce an overall decrease in soluble-N fractions, particularly proteins. The results can provide guidelines on how to utilise these seed(s) and their products. Furthermore, appropriate processing is needed to reduce their antinutrients for human nutrition.

Nutritional assessment of protein from beans (Phaseolus vulgaris L) processed at different pH values, in growing rats

“…6,7,12,13 However, recent work has brought to light the importance of the pH of the soaking or cooking solution, in view of the effect of pH on other seed components such as antinutritional factors, 14 starch 15 and ®bre. 16,17 Modi®cations in these factors can affect the nutritive utilisation of legume protein.…”

Influence of Dehydration Process in Castellano Chickpea: Changes in Bioactive Carbohydrates and Functional Properties

“…Determination of residual ashes and proteins (as Kjeldahl N×5.40) was carried out in the residues for corresponding corrections. Total dietary fibre (TDF) was calculated as sum of IDF and SDF [11].…”

“…Proximate chemical composition analysis of the seed flours including total ash, crude fat, and crude protein were performed according to official AOAC procedures [11]. Ash was calculated from the weight remaining after heating the sample at 550°C for 2 h. Soxhlet extraction was employed to determinate crude fat.…”

“…Mes-Tris AOAC method 991.43 was used for dietary fibre (DF) determination [11]. Dietary fibre fractions were obtained as indigestible residues after enzymatic digestion of nondietary fibre components; the insoluble residues were isolated by filtration and soluble fibre was precipitated with ethanol.…”

Performance of Northwest Washington Heirloom Dry Bean Varieties in Organic Production

“…Cooking time is important to consumers who are purchasing beans in the dry form, especially for institutions, such as schools, that are preparing large quantities of beans. While several studies have investigated the influence of storage on cooking qualities, no studies have evaluated the cooking time of heirloom varieties [26,27]. The protein content of heirloom dry bean varieties is also generally unknown in comparison to newer varieties [28].…”