Profile and functional properties of seed proteins from six pea (Pisum sativum) genotypes

Abstract

Extractability, extractable protein compositions, technological-functional properties of pea (Pisum sativum) proteins from six genotypes grown in Serbia were investigated. Also, the relationship between these characteristics was presented. Investigated genotypes showed significant differences in storage protein content, composition and extractability. The ratio of vicilin:legumin concentrations, as well as the ratio of vicilin + convicilin: Legumin concentrations were positively correlated with extractability. Our data suggest that the higher level of vicilin and/or a lower level of legumin have a positive influence on protein extractability. The emulsion activity index (EAI) was strongly and positively correlated with the solubility, while no significant correlation was found between emulsion stability (ESI) and solubility, nor between foaming properties and solubility. No association was evident between ESI and EAI. A moderate positive correlation between emulsion stability and foam capacity was observed. Proteins from the investigated genotypes expressed significantly different emulsifying properties and foam capacity at different pH values, whereas low foam stability was detected. It appears that genotype has considerable influence on content, composition and technological-functional properties of pea bean proteins. This fact can be very useful for food scientists in efforts to improve the quality of peas and pea protein products.

Keywords: emulsifying; extractability; foaming; pea proteins.

Figure 1.

Electrophoretic patterns of pea bean proteins under reducing (R) and non reducing (N.R) conditions. Calvedon (1R, 1NR); L1 (2R, 2NR); L2 (3R, 3NR); L3 (4R, 4NR); Maja (5R, 5NR); Miracle of America (6R, 6NR), M.w. molecular weight standards. Tris-HCl (pH 8.0) extracts with 2-mercaptoethanol (reducing conditions) and without 2-mercaptoethanol (non reducing conditions).

Figure 2.

Electrophoretic patterns of pea protein isolates under reducing conditions. 1. L1; 2. L2; 3. L3; 4. Maja; 5. Calvedon; 6. Miracle of America; 7. M.w.-molecular weight markers.

Figure 3.

Solubility of pea protein isolate at different pH values *. * Bars with same letter differ (p < 0.05). Means were of triplicate determinations.

Figure 4.

Emulsifying activity index (EAI) of pea protein isolates at different pH values *. * Within a parameter, bars with same letter differ significantly (p < 0.05). Means were of triplicate determinations.

Figure 5.

Emulsion stability index (ESI) of pea protein isolates at different pH values *. * Within a parameter, bars with same letter differ (p < 0.05). Means were of triplicate determinations.

Figure 6.

Foaming capacity (FC) of pea protein isolates at different pH values *. * Within a parameter, bars with same letter differ significantly (p < 0.05). Means were of triplicate determinations

Figure 7.

Foam stability (FS) of pea protein isolates at different pH values *. * Within a parameter, bars with same letter differ (p < 0.05). Means were of triplicate determinations.