CHEMICAL, NUTRITIONAL AND FUNCTIONAL-CHARACTERIZATION OF PROTEINS EXTRACTED FROM WILD MUSTARD (BRASSICA-CAMPESTRIS, BRASSICACEAE) SEEDS FROM NUEVO-LEON, MEXICO

Cultivated oilseeds are very important sources of protein-rich pastes that are widely used for their nutritional and functional properties i n human foods and animal feed. The purpose of this research was to det ermine the potential of wild Brassica campestris seeds as a source of protein isolates and their characterization. Wild mustard meal contain ed 33.5% lipids, 26% protein, 13.4%, crude fiber, 4.4% ash, 22.6%, nit rogen free extract and 4.8% moisture. It contained low levels of phyta tes (32 mg/100 g) and glucosinolates (0.92%), and the thioglucosidase could be inactivated through heat (90 degrees C/18 min) or after extra cting the Oil with hexane at 80 degrees C for 2 hr. Dehulled and defat ted meal contained 3.8% crude fiber, 7%, ash, and 48% protein, with a digestibility of 92.8% and a nutritive value of 98% (relative to casei n). Phytate levels increased to 67 mg/100 g and glucosinolates to 2.3% . Protein was extracted from this meal at pH's between 6 and 11. Maxim um yields (> 74%) were obtained at pH 7, 7.5 and 8, coinciding,vith a minimum extraction of phytate (70%. SDS-PAGE electrophoresis identifie d 12 protein bands with MW between 10 and 74 kDa in these extracts. Pr otein extracted at pH 7 was precipitated at pH's between 3.5 and 5.5, with maximum yield at pH 3.5 (53%), but the pH 4 isolate was chosen (y ield 36%) since it contained negligible amounts of phytates and no glu cosinolates. It contained 93% protein and a nutritive value of 91%, an d higher levels of sulphur amino acids and lysine than cereals and leg umes. The best functional characteristics were its foaming capacity, f oam stability and oil binding capacity (better than soybean isolate).