摘要
In order to improve beef color and color stability, step-chilling （SC） was applied on excised bovine Iongissimus lumborum muscle, with chilling starting at 0-4℃ for 5 h, then holding the temperature at 12-18℃ for 6 h, followed by 0-4℃ again until 24 h post-mortem, pH and temperature were measured during rigor on SC loins as well as those subjected to routine chilling （RC, 0-4℃, till 24 h post-mortem）. Color L＊, a＊, b＊ values, metmyoglobin （MetMb） content, MetMb reducing ability （MRA） and NADH content were determined on samples aged for 1, 7, and 14 d. Sarcoplasmic proteome analysis was only conducted on d 1 samples. The results showed muscles subjected to SC maintained a temperature at around 15℃ for 5 to 10 h post-mortem, and exhibited a slow temperature decline, but rapid pH decline. Beef steaks treated with SC had higher L＊, a＊, b＊ and chroma values than those of RC samples at 1 and 7 d chilled storage （0-4℃）, while showing no significant difference for a＊, b＊ and chroma values at d 14. The SC samples also exhibited a lower relative content of surface MetMb, higher MRA and NADH content, compared with RC beef steaks during storage, indicating the SC-treated beef showed an improved color stability. Eleven differential protein spots/nine proteins were identified by two-dimensional gel electrophoresis and mass spectrometry, and those proteins were mainly involved in redox, chaperone binding, metabolic and peroxidase activity. Oxidoreductases play a role in decreasing the oxidation-induced myoglobin oxidation and benefiting the production of NADH, and finally improving the colour of beef. Of these, pyruvate dehydrogenase E1 component subunit beta showed a positive correlation with color L＊, a＊, b＊ values and accounted for more than 60% of the variation in color values; this protein can be considered as a potential beef color biomarker. The present study provided valuable information for studies on the molecular mechanism of color improvement from step-chilling, as well as for identifying markers associated with beef color.
In order to improve beef color and color stability, step-chilling （SC） was applied on excised bovine Iongissimus lumborum muscle, with chilling starting at 0-4℃ for 5 h, then holding the temperature at 12-18℃ for 6 h, followed by 0-4℃ again until 24 h post-mortem, pH and temperature were measured during rigor on SC loins as well as those subjected to routine chilling （RC, 0-4℃, till 24 h post-mortem）. Color L＊, a＊, b＊ values, metmyoglobin （MetMb） content, MetMb reducing ability （MRA） and NADH content were determined on samples aged for 1, 7, and 14 d. Sarcoplasmic proteome analysis was only conducted on d 1 samples. The results showed muscles subjected to SC maintained a temperature at around 15℃ for 5 to 10 h post-mortem, and exhibited a slow temperature decline, but rapid pH decline. Beef steaks treated with SC had higher L＊, a＊, b＊ and chroma values than those of RC samples at 1 and 7 d chilled storage （0-4℃）, while showing no significant difference for a＊, b＊ and chroma values at d 14. The SC samples also exhibited a lower relative content of surface MetMb, higher MRA and NADH content, compared with RC beef steaks during storage, indicating the SC-treated beef showed an improved color stability. Eleven differential protein spots/nine proteins were identified by two-dimensional gel electrophoresis and mass spectrometry, and those proteins were mainly involved in redox, chaperone binding, metabolic and peroxidase activity. Oxidoreductases play a role in decreasing the oxidation-induced myoglobin oxidation and benefiting the production of NADH, and finally improving the colour of beef. Of these, pyruvate dehydrogenase E1 component subunit beta showed a positive correlation with color L＊, a＊, b＊ values and accounted for more than 60% of the variation in color values; this protein can be considered as a potential beef color biomarker. The present study provided valuable information for studies on the molecular mechanism of color improvement from step-chilling, as well as for identifying markers associated with beef color.
基金
supported by the earmarked fund for the China Agriculture Research System(beef)(CARS-37)
the Special Fund for Innovation Team of Modern Agricultural Industrial Technology System in Shandong Province,China(SDAIT-09-09)
the Funds of Shandong“Double Tops”Program,China(SYL2017XTTD12)
