In vitro assessment of antioxidant capacity and phenolic contents of some lentil (Lens culinaris L.) cultivars commonly consumed in Algeria

Lentil (Lens culinaris L.) is one of the ancient crops cultivated in the world. In addition to its nutritional value, lentil seeds have been getting growing attention for their health benefits in the human diet, by containing a wide variety of bioactive phytochemicals. The present study aims to investigate the phenolic compound composition and the antioxidant capacity of six lentil cultivars, commonly consumed in Algeria. Four varieties of whole lentils with colored seed coats (black, brown, green and white) and two cultivars of colored cotyledon dehulled lentils (red and yellow) were studied. Two solvents were used for the extraction of phenolic compounds present in the lentil seeds. Several antioxidant phytochemicals, namely total carotenoid content, total phenolic content (TPC), total flavonoid content (TFC) and total proanthocyanidin content (TPAC), were investigated. Additionally, the antioxidant capacity of the six lentil cultivars was determined using three different assays: total antioxidant activity (TAA), 1,1-diphenyl-2-picrylhydrazylradical scavenging activity (DPPH-RSA) and the ferric reducing power (FRP). The results showed that cultivar and extraction solvent had significant effect (p < 0.05) on the phenolic composition (TPC, TFC and TPAC) and the antioxidant properties (TAA, DPPH-RSA and FRP) of the lentil seeds. The whole lentils with colored seed coats (black, brown and green) were found to have the highest TPC, TFC, TPAC as well as the greatest antioxidant capacity (TAA, DPPH-RSA and FRP), especially for acidic 80% acetone extraction, compared to the colored cotyledon dehulled lentils (red and yellow). High correlations between phenolic compounds and antioxidant activities of lentil extracts were observed. These findings support that lentil extracts may be employed as a natural source of antioxidants in functional foods and provide important data for breeding or cultivating lentil cultivars with high value of bioactivity.