Effect of heat treatment and mineral and vitamin supplementation on the nutritive use of protein and calcium from lentils (Lens culinaris M.) in growing rats.

OBJECTIVE The effects of heat treatment, supplementation of a mineral and vitamin premix, and 4% olive oil on the bioavailability of protein and calcium from Lens culinaris M., var vulgaris, cultivar. magda-20 were studied in growing rats. METHODS Nutrition assessment was based on chemical analysis of lentil protein, energy, total and available starch, lipid and calcium composition, and the digestive and metabolic use of nitrogen and calcium by rats. Lentils used for the present study had crude protein and calcium contents of 25.5% and 0.07%, respectively. Heating lentils to 120 degrees C at 1 atm for 30 min decreased trypsin inhibitor activity, phytate, and tannin content by 76%, 8%, and 12%, respectively, but did not improve dietary intake or digestive use of protein compared with untreated raw control lentils. RESULTS Mineral, vitamin, and olive oil supplementation of raw or autoclaved lentils significantly improved daily food intake and nutritive use of nitrogen and calcium. The best results were obtained for the rats fed with a diet of raw lentils supplemented with a premix of minerals and vitamins. CONCLUSIONS There was a direct correlation between calcium balance and weight gain in animals (r = 0.89) and between the calcium balance and nitrogen balance (r = 0.86).