The effect of pH, sucrose, salt and hydrocolloid gums on the gelling properties and water holding capacity of egg white gel

Abstract

The aim of this investigation was to evaluate the effect of pH variation, sucrose, salt and hydrocolloid gums (xanthan, guar, karaya and locust bean) addition on the gelling properties and the water holding capacity (WHC) of the egg white (EW) gel. Tree levels of pH (4.5, 6.5, 8.0), sucrose/salt (1, 3, 6% w/w) and hydrocolloids (0.01%, 0.10%, 0.20% w/w) were tested in this study. Obtained results showed that mechanical properties and WHC of the EW gel were decreased significantly by pH variation. Addition of salt and sugar improved firmness and elasticity of the EW gel. However, the presence of salt decreased the WHC of the gel. Whereas, in the presence of sugar, WHC was slightly improved. The presence of hydrocolloids in EW gel is associated with the modification of the functional properties of the EW proteins. Xanthan gum decreased hardness and strength and increased WHC of the gel to 97.18% at 0.2%. Guar and karaya gums increased mechanical properties of EW gel at the lowest concentration (0.01%). Locust bean gum was shown to enhance texture profile of EW gel at all tested levels. WHC was significantly improved in the presence of food gums. Microstructure observations of EW gels were also carried out by environmental scanning electron microscopy.