Nutritional Composition and Functional Properties of Commonly Consumed Lentils: Impact of Commercial Lentil Types and Cooking Processes

Background/Objectives: Lentils are part of the legume family, containing high proteins, minerals, fibers, and bioactive compounds. Although lentils are regarded as a functional food due to their health-promoting nutritional profile, the impacts of cultivar differences and cooking processes on their nutritional and functional properties are not fully understood. Methods: The nutrition composition (e.g., minerals) and water- or oil-holding capacity (WHC or OHC) of six major raw and cooked lentil types (red, yellow, green, brown, French green, black) were determined by inductively coupled plasma mass spectrometry, as well as biochemical and biophysical assays. Results: The mineral, protein, fat, resistant starch, fiber (soluble and insoluble), and total phenolic content of raw lentils are significantly different across types. For instance, iron ranged from 4.6 mg/100 g to 6.8 mg/100 g and protein from 25% to 29%, with the highest levels observed in black lentils. Importantly, the cooking process was a primary factor determining the lentils’ final nutritional composition and functional properties. Compared to raw samples, cooked lentils exhibited marked increases in total dietary fiber (e.g., 38% in red lentils), resistant starch (e.g., 93% in red lentils), phenolic content (e.g., 110% in French green lentils), and oil-holding capacity (e.g., 52% in brown lentils). Conclusions: While the nutritional profiles of raw lentils vary significantly between types, their respective WHC and OHC remain relatively stable, and cooking processes enhance nutritional scoring metrics, such as increasing OHC and resistant starch. These data, particularly the high health indices of black lentils, highlight the nutritional value and health benefits of lentil types.