Rheological, surface and colorbvietric properties of egg albumen gel affected by pH

Abstract

Studies were conducted to evaluate the effects of albumen at naturally existing pH ranges on the functional and gel characteristics. Albumen was obtained from freshly laid shell eggs. The pH of albumen was altered using either IN NaOH or IN HC1 to obtain a pH of 7.5, 8.0, 8.5, 9.0, 9.5 and 10.0. The altered albumen was tested for its foaming capacity (FC), foam stability (FS), and bake volume (BV). Albumen gels were prepared and tested for firmness (FM), strain at failure (NF), and stress at failure (SF) as well as their color attributes (Hunter L, a, and b). In general, FC and BV of the albumen decreased (P<0.05) as the pH increased. The BV of the albumen was affected by FS than FC for all the adjusted pH ranges. A denser structure was observed for albumen gels as the pH increased. The FM, NF and SF of albumen gels increased, and Hunter L and a values decreased with the increasing adjusted pH. The FM, NF, SF and Hunter L value of albumen gel could be used as quality indicators in evaluating the changes of texture and color with pH.