Effect of cooking time on the nutritional and anti-nutritional properties of red and black beans of Phaseolus lunatus (L.) consumed in south and east of Côte d’Ivoire

Legume seeds, particularly those of the Phaseolus lunatus (L.), are an important source of vegetable protein, fiber and micronutrients in the diet of the Ivorian population. However, these seeds contain anti-nutritive factors that limit their use. This study allowed us to evaluate the effect of cooking time on the nutritional and anti-nutritional parameters of Phaseolus lunatus (L.) bean seeds for a better utilization of these seeds. Red and black seeds harvested at stage 4 (52 days) of Phaseolus lunatus (L.) bean were cooked at 100 °C for 45, 60 and 75 minutes. The nutritional and anti-nutrional composition was determined on uncooked (control) and cooked samples. The results obtained showed an increase in carbohydrate (64.16 to 71.56%), energy value (29.68 to 36.27%) and fiber (4.62 to 6.05%) followed by a reduction in protein (4.62 to 6.05%), ash (4.62 to 6.05%) and fat (4.62 to 6.05%). The same cooking also caused a reduction in total phenols (59.18 to 72.49%), phytates (33.32 to 39.18%), oxalates (64.64 to 68.91%), tannins (62.07 to 67.59%), cyanidric acid (58.18 to 61.38%) and antioxidant activity (53.71 to 63.94%). The analysis of the seeds cooked at different times (45, 60 and 75 minutes) also shows us that the B vitamins and minerals decrease during cooking. The consumption of Phaseolus lunatus bean seeds cooked at 45 minutes could be recommended in human diet due to the decrease of oxalates and phytates to prevent and treat some diseases such as cancer, inflammatory diseases, cardiovascular diseases and neurogenerative diseases.