Abstract:
The purpose of this study was to analyze the effects of very fast chilling (VFC) on early postmortem lamb meat quality and myofibrillar protein characteristics, and provide theoretical basis for the development of pre-rigor maintain quality techniques for fresh meat. The
longissimus thoracis et lumborum muscles were collected within 1 h after slaughter, which were used as experimental material, the muscles were assigned into three chilling groups respectively: Control group (the chilling rate was 4.8 ℃/h), Chilling 1 group (the chilling rate was 23.0 ℃/h), Chilling 2 group (the chilling rate was 25.1 ℃/h). Chilling 1 and Chilling 2 groups were both very fast chilling treatment groups. The analysis focused on the impacts of varying chilling rates on lamb quality and myofibrillar protein characteristics, and the mechanistic basis was clarified. The results showed that pH, myofibrillar protein (MP) solubility, water retention of MP gel, MP emulsification activity, MP emulsification stability and ATP content of the samples from the Chilling 1 and Chilling 2 groups were significantly higher than those from the Control group, but shear force, cooking loss, MP gel hardness and lactic acid content were significantly lower than Control group (
P<0.05). At 24 h postmortem, the MP solubility of Chilling 1 and 2 Groups were 16.13% and 29.84% higher than that of the Control group, respectively, with corresponding 3.02% and 5.93% improvements in water retention of MP gel. At 72 h postmortem, the emulsifying activity and emulsifying stability of Chilling 2 group were 51.63 m
2/g and 41.18%, respectively, both significantly higher than the emulsifying activity (43.16 m
2/g) and emulsifying stability (37.76%) of the Control group. There was no difference in myofibrillar protein solubility of lamb meat within 72 h postmortem, no difference in MP gel water retention and MP emulsification activity were observed within 12 h postmortem. This showed VFC treatment maintained the pre-rigor lamb meat quality to a certain extent. The results of ATP and lactic acid contents in lamb meat showed that the lactic acid contents in the Chilling 1 and Chilling 2 groups were significantly lower compared to the Control, while the ATP content was significantly higher than Control (
P<0.05). The results demonstrated that the Chilling 1 and Chilling 2 groups slowed down the rate of glycolysis, which in turn delayed the decline of pH levels, and this contributed to maintaining pre-rigor lamb meat quality. These results suggested that VFC treatment could effectively maintain pre-rigor lamb meat quality, and the treatment effect with a chilling rate of 25.1 ℃/h was more significant.