Structural and rheological characterization of liquid egg white modified with phospholipase A2 enzyme

The objective of this research was to evaluate the efficiency of phospholipase A(2) (PLA) enzyme treatments (0.1%, 0.2%, and 0.3% by -v/v) on liquid egg white (LEW). The rheological behaviors and physico-functional characteristics such as foam capacity (FC), foam stability, turbidity, color parameters, and pH-values were evaluated during the 27 days at 4 degrees C. The correlation coefficient (R-2) were best fitted for the Herschel-Bulkley model in all LEW samples. The PLA increased FC compared to nontreated LEW. The use of PLAs were also significantly (p < .05) decreased turbidity, control, 0.1%, 0.2%, and 0.3% of PLA with 0.76 +/- 0.07, 0.64 +/- 0.06, 0.57 +/- 0.04, and 0.62 +/- 0.04, respectively. Significant changes in L* (lightness) was observed, while 0.1% treated LEW showed lower L* and higher a* (redness and greenness) values than the control (p < .05). The b* (yellowness and blueness) color of the treated samples remained stable except for the untreated samples (12.65 +/- 0.14 to 5.71 +/- 1.01). A considerable (p < .05) increase was observed in b* values, while lowest turbidity (0.57 +/- 0.04) was obtained 0.2% treatment, while the best treatment was the 0.3% PLA with higher FC and lower foam stability. The effect of enzyme treatment concentrations was statistically nonsignificant (p > .05) on the pH values before and after the treatment. Practical applications The modification of the phospholipids presents in egg white during the egg breaking or in storage is critical in the egg processing. The fats and phospholipids from the yolk lead to migrate to egg white. The PLA enzymes could be used to improve the functionality or recover the adverse effects of the fresh eggs during aging. Understanding the effect of enzymes of LEW has great importance for the value-added new product development in the egg processing industry and to enhance the functionality in final product such as baking products.