Effect of food processing on the changes in the antioxidant capacity of lentil cultivars

Lentils have recently attracted much interest due to serving as an excellent dietary source of legumes that are rich in dietary fiber, carbohydrates, protein, various vitamins, minerals, and several health-beneficial components. Epidemiological studies have reported their effects in lowering cholesterol and reducing the incidence of colon cancer, heart diseases, and type-2 diabetes. In the present study, effects of germination, boiling, and dehulling on the antioxidant capacity of soluble and insoluble bound phenolics of lentils were conducted using in vitro methods such as 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability, reducing power, hydroxyl radical scavenging ability, and oxygen radical absorption capacity (ORAC). In addition, identification and quantification of soluble and insoluble bound phenolic in lentils were carried out using HPLC-ESI-MSⁿ. An increasing trend of antioxidant capacity in insoluble bound phenolics and a declining trend in soluble phenolics (except total phenolic contents) were observed during 4 days of germination. Boiling process decreased insoluble bound phenolics in all lentil cultivars and most phenolic compounds existed in the hull portion than in the dehulled grains. This study provides useful background knowledge for better understanding of antioxidant capacity of lentils and effects of food processing on changes of insoluble bound phenolics that are often ignored in many evaluations by different research groups.