Physicochemical, functional and cooking properties of under explored legumes, Canavalia of the southwest coast of India

Nutritionally potential under explored wild legumes viz., Canavalia cathartica and Canavalia maritima are widely distributed in mangroves and sand dunes, respectively, in Southwest coast of India. Physicochemical, functional and cooking properties of dried seeds of these legumes have been evaluated. Seeds and cotyledons of C. cathartica are larger and possessing higher hydration and swelling capacity than that of C. maritima indicating higher permeability and softness. The crude protein of C. maritima and C. cathartica were found to be higher than common pulses. The pH vs. protein solubility profile was almost similar with minimum solubility at pH 4 (27.8-28.1%). C. maritima showed higher oil absorption capacity (1.53 ml/g) as well as water absorption (0.1 M) capacity. The gelation capacity was minimal at 0.1 M NaCl and pH 4 for both the seed flours. Addition of carbohydrates (starch, lactose, maltose and sucrose) reduced the lowest gelling capacity of C. maritima except for maltose in C. cathartica. Emulsifying activity (EA) and emulsifying stability (ES) diminished with increasing concentration of flours. Minimum EA and ES were attained at pH 4 and maximum at pH 10 in both seed flours. Maximum EA for C. cathartica and C. maritima (62% vs. 72.6%) was attained at 0.4 M NaCl. The ES vs. flour concentration, pH and ionic strength profiles did not differ much between C. maritima and C. cathartica. Peak foam capacity (FC) and stability (FS) were achieved at 6% (w/v) of C. maritima flour, while the same was attained at 8% (w/v) of C. cathartica. The FC and FS of the seed flours improved with increasing pH (pH 2-10). C. maritima flour exhibited the better FC (27.7%), while C. cathartica exhibited better FS (44.42%) at pH 10. Although highest FC was attained at 0.4 M NaCl in both flours, C. maritima was found to be superior (30.5% vs. 28.5%). The flour of C. maritima attained the highest FS at 0.2 M NaCl than C. cathartica (0.4 M NaCl). The minimum cooking time for cotyledons of C. cathartica was more and higher gruel solid loss was reported due to its high L/B ratio. The Pearson correlation coefficients revealed that functional properties of seed flours vary due to their chemical composition.