Use of low degree of hydrolysis (DH < 10%) with enzymatic treatment can produce protein hydrolysates with functional properties superior to the raw material. Suspensions of Phaseolus lunatus protein isolate (PPI) were treated with one of two commercial enzymes (Alcalase or Flavourzyme) at 50°C and pH 8.0. DH with Alcalase was greater than Flavourzyme at 5 or 15 min of reaction. Alcalase-prepared hydrolysates had more peptides than those prepared with Flavourzyme. All the hydrolysates had higher solubility than the PPI, the highest being for the Alcalase-prepared hydrolysate at 15 min reaction time. Overall, the Alcalaseprepared hydrolysates had better solubility characteristics, whereas the Flavourzyme-prepared hydrolysates had better film properties (maximum emulsifying capacity and the highest foam formation values). This is probably because of the greater ease of movement toward the interface as shown by their high surface hydrophobicity values. The Alcalase-prepared hydrolysates had generally low or nonexistent film properties.

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Physicochemical, functional and digestibility analyses were done of dehydrated quail egg white to determine its possible practical applications. Quail egg white was dehydrated by air convection using one of two temperatures and times: M1 (65˚C, 3.5 h), M2 (65˚C, 5.0 h), M3 (70˚C, 3.5 h) and M4 (70˚C, 5.0 h). Lyophilized quail egg white was used as a standard. All four air-dried treatments had good protein levels (92.56% to 93.96%), with electrophoresis showing the predominant proteins to be lysozyme, ovalbumin and ovotransferin. Denaturation temperatures ranged from 81.16˚C to 83.85˚C and denaturation enthalpy values from 5.51 to 9.08 J/g. Treatments M1-4 had lower water-holding (0.90-2.95 g/g) and oil-holding (0.92-1.01 g/g) capacities than the lyophilized treatment (4.5 g/g, 1.95 g/g, respectively). Foaming capacity was pH-dependent in all five treatments, with the lowest values at alkaline pH and the highest (153% to 222%) at acid pH (pH 2). Foam stability was lowest at acid pH and highest at alkaline pH. Emulsifying activity in the air-dried treatments was highest at pH 8 (41%-46%). Emulsion stability was pH-dependent and highest in M3 between pH 2 and 4 (96.16% to 95.74%, respectively). In the air-dried treatments, in vitro protein digestibility was as high as 83.02% (M3).

The legumes Canavalia ensiformis and Mucuna pruriens are underexploited in tropical Mexico. Their seeds have good nutritional potential, but contain antinutritional factors. Physicochemical and antinutritional properties were determined for raw flours (RF) and protein isolates (PI) produced from these legumes. Protein content in the PI was 737 g kg -1 for C. ensiformis and 666 g kg -1 for M. pruriens. Protein isolation improved in vitro digestibility, while maintaining high lysine levels and adequate sulphur amino acids content. Antinutritional factors such as cyanogenic glucosides, cyanide precursors from hydrolysis, tannins and trypsin inhibitors were lower in the PIs than in the RFs. The reduction in canavanine levels, a structural analogue of arginine, in the C. ensiformis PI was noteworthy. These PIs thus have potential applications in the development of new food ingredients in tropical regions using processes that improve nutritional value.

Functional properties were identified for the total globulin (TG), 7S and 11S fractions of Lima bean (Phaseolus lunatus L.) seeds. The 11S component accounted for 58.3% of TGs and the 7S for 41.7%. Solubility was higher in the 7S fraction, especially at alkaline pHs. Water-holding capacity was similar (3 g water/g sample) in both globulin fractions. Oil-holding capacity was higher in the 11S fraction, which also exhibited better foaming capacity and foam stability than the 7S and TG fractions at alkaline pHs. The TG and 7S fractions exhibited low emulsifying capacity and emulsion stability at different pHs (5, 7 and 9), but the 11S fraction had relatively higher values. In suspension at low concentrations, all fractions exhibited shear-thinning (pseudoplastic) behavior. The studied Lima bean globulin fractions exhibit functional properties which make them potentially apt for use in some industrial food systems.