Nutritional Assessment of Raw and Processed Faba Bean (Vicia faba L.) Cultivar Major in Growing Rats

We tested the effects of several processing methods on the nutritional value of faba beans. Nutritional assessment was based on chemical analyses of legume protein content and on the digestive and metabolic utilization in rats. Protein content in Vicia faba (V. faba) was 28%, and the supply of essential amino acids, except for sulfur-containing acids, was sufficient to cover the rat’s nutritional requirements. Food intake was significantly lower in animals fed with raw faba beans than in the control group given the casein diet. We attribute this to the deficient levels of some amino acids and the presence of antinutritional factors (R-galactosides and tannins) in faba beans. All processing methods except heating under pressure increased food intake. The digestive utilization of V. faba protein was high, although lower than that of the casein diet. This may be related to the presence of protease inhibitors and tannins in faba beans. Nitrogen retention was similar in control animals and rats fed with raw beans; however, growth was faster in the former group, probably because of the better balance in amino acids supplied by this diet. Soaking in basic medium with or without subsequent cooking greatly increased growth, probably as a result of greater nitrogen retention and utilization of carbohydrates, which may have been stored as fat.