Cross-Linking of White Proteins in Soft-Shell Turtle Eggs Using Transglutaminase, Reductant, and Thermal Pretreatment

The effects of transglutaminase (TGase), reductant, and thermal treatment on the cross-linking white proteins in soft-shell turtle eggs were investigated. Egg denatured by reductant (0.83% 2-mercaptoethanol, 2-ME) pretreatment (95 °C 5 min), then catalyzed TGase (1.0 unit/mL). SDS–PAGE showed that without any pretreatments, three major egg (210 kDa, 115 76 kDa proteins) inferior substrates for TGase. Only portions 210 protein (7.9%), (11.4%), (42.9%) polymerized into high-molecular-weight (MW) polymers (>180 kDa) after incubation 3 h at 40 °C. However, combined use with 0.83% 2-ME led to a significant increase (p < 0.05) rate polymerization h: (90.8%), (69.5%), (72.2%). Particle size analysis indicated these cross-linked high-MW 2000–10,000 nm size. Based experimental results, heat are more prone TGase-induced cross-linking.