Abstract：The effects of water bath heating at different temperatures on the formation of rainbow stains in bovine Semitendinosus muscle under cold storage conditions were studied. Fresh muscle was heated in a water bath (97 ℃) until the internal temperature reached 70, 80 or 90 ℃, and then chilled at 4 ℃ for 5 d. Changes in the intensity of iridescent color, non-heme iron content, protein and lipid oxidation, and CIELab color parameters were measured during the storage period. The mechanism of the effect of water bath heating on the formation of rainbow spots was explored. The results showed that the rainbow spot intensity increased with the increase of heating temperature or refrigeration time. Luminance value (L*) and yellowness value (b*) increased slightly, while redness value (a*) decreased slightly; these changes were statistically significant (P < 0.05). During cold storage, non-heme iron content, thiobarbituric acid reactive substance (TBARs) content, and protein carbonyl content increased significantly (P < 0.05), whereas free sulfhydryl group content decreased significantly (P < 0.05). Correlation analysis showed that the rainbow spot intensity was significantly positively correlated with non-heme iron content, carbonyl content and TBARs value (P < 0.05), but significantly negatively correlated with a* (P < 0.01) and free sulfhydryl group content (P < 0.05). The high heme iron content could promote a rapid rise in TBARs value from day 0 to 1 of storage and accelerate the process of protein oxidation. Protein and lipidoxidation process occurred simultaneously and promoted each other, thereby jointly affecting the formation of rainbow spots.
2019, Vol. 33 
