Gelation of Frozen-Defrosted Egg Yolk as Affected by Selected Additives: Viscosity and Electrophoretic Findings

AT A temperature of −6°C. or below egg yolk loses its fluidity. This change is irreversible and has been termed gelation. Several factors affecting this phenomenon have been established. The mechanism involved, however, remains to be elucidated. This physical alteration in egg yolk may be averted by super-cooling (−11°C.) or freezing in liquid air (−190°C.) and thawing rapidly in mercury at 30°C. (Lopez et al., 1954; Smith, 1962). The average freezing point for egg yolk has been reported as −0.65°C. (Lopez et al., 1954; Smith, 1954; Powrie et al., 1963). Freezing and defrosting rates and storage temperatures and time affect the degree of gelation (Pearce and Lavers, 1949; Lea and Hawke, 1952; Lopez et al., 1954; Marion and Stadelman, 1958; Powrie et al., 1963). On freezing and thawing of yolk, physical changes in the environment may be responsible for molecular reorientation (Lovelock, 1957; Fisher and Gurin, 1964). Water molecules…