摘要
为了从分子水平探索牦牛冷鲜肉贮藏品质特性,在冰温(-2℃)和冷藏(0℃)条件下贮藏过程中,研究牦牛肉感官品质、丙二醛含量、菌落总数和色泽的变化,利用低场核磁共振技术(low-field nuclear mag-netic resonance,LF-NMR)研究牦牛肉在贮藏过程其水分迁移规律,采用傅立叶红外光谱技术(fourier transform infrared spectroscopy,FTIR)研究牦牛肉在贮藏过程其蛋白质结构变化。结果表明:牦牛肉在冰温贮藏条件下贮藏24 d仅降为"二级鲜肉",菌落总数为5.12 lg(CFU/g),而冷藏条件下贮藏至18 d已为"二级鲜肉",菌落总数为5.25 lg(CFU/g)至24 d已腐败变质,菌落总数为6.28 lg(CFU/g)。牦牛肉样在贮藏过程色泽红度值先上升后下降,与冰温贮藏相比,冷藏条件下降速度更显著(P<0.05)。牦牛肉丙二醛含量随贮藏时间延长逐渐增加,冷藏条件与冰温贮藏条件比较,丙二醛增加更快。上述数据表明冰温对牦牛肉的贮藏保鲜效果更好。同时,在上述两种贮藏条件下,牦牛肉中结合水含量变化趋势相同,两种贮藏条件下结合水含量差异不显著(P>0.05),不易流动水含量在冰温条件下比冷藏条件下波动小,自由水含量在冷藏条件下比冰温条件下波动小。不同贮藏条件下牦牛肉弛豫时间对应的结合水和自由水迁移明显,且冰温条件变化幅度低于冷藏条件,说明冰温条件更利于维持水分子与其他生物大分子相互作用,间接说明冰温保鲜效果更佳。对于贮藏过程蛋白质二级结构变化,冰温条件下贮藏18 d后无规则卷曲相对平均含量,比冷藏条件下无规则卷曲相对平均含量低,且差异显著(P<0.05)。综合分析表明,与冷藏条件相比,冰温条件下牦牛肉结合水、蛋白质分子结构更加稳定,对维持肉生理、生化品质更为有利,因而冰温贮藏比冷藏效果更好。研究为冷鲜肉贮藏保鲜的基础研究提供新的方法参考。
In order to explore the storage quality of yak meat from the molecular level, this study evaluated the effects of ice temperature(-2 ℃) and chilled(0 ℃) storage on the change of sensory quality, malondialdehyde content, the total bacterial number, and color value of fresh yak meat. Low-field nuclear magnetic resonance(LF-NMR) was used to study the moisture migration in yak meat during storage. Fourier transform infrared spectroscopy(FTIR) was applied to investigate the structural protein changes in yak meat during storage. The results showed that the sensory quality of fresh yak meat after 24 days of storage at -2 ℃ was still kept the secondary freshness according to Chinese national standard, the total bacterial number was 5.12 lg(CFU/g). But the sensory quality of fresh yak meat after 18 days of storage at 0°C reached the secondary freshness with the total bacterial number of 5.25 lg(CFU/g).The quality deterioration was found in yak meat after 24 days of storage at 0 ℃, the total bacterial number reached 6.28 lg(CFU/g). The color value(a* value) of fresh yak meat firstly rose and then decreased, but the color value of yak meat stored at-2 ℃ exhibited fewer changes than test samples stored at 0 ℃. The results showed that the content of malondialdehyde in fresh yak beef increased significantly with the prolongation of storage time. The malondialdehyde content in yak meat stored at 0 ℃ increased faster than that stored at -2 ℃. Those data indicated that the ice temperature(-2 ℃) has a better efficacy of storage and preservation for fresh yak meat. At the same time, the combined water pT21 in chilled fresh yak meat was similar to that of pT22 under the different storage conditions, and the difference was not significant(P>0.05). The non-flowing water pT23 in fresh yak meat stored at -2℃ fluctuated less than that stored at 0 ℃. The change of free water pT24 was opposite to that of non-flowing water. Under different storage conditions, the relaxation times of yak meat T21, T22, and T24 were corresponded to the combined water and free water, respectively. The combined water in yak meat stored at-2 ℃showed fewer changes than that of samples at 0℃. This indicated that ice temperature(-2 ℃) storage were more conducive to maintaining the interaction of water molecules with other biological macromolecules. These data indirectly revealed that the ice temperature(-2 ℃) storage has a greater storage and preservation effect on the fresh yak meat. The comprehensive analysis showed that compared with refrigeration conditions, the combination of water and protein molecular of the yak beef was more stable than that of samples under ice temperature conditions, which was more favorable for maintaining physiological and biochemical parameters for meat quality determination. Therefore, the ice temperature storage used for meat preservation was better than the chilled storage. The experiment provided a new reference method in the research of the storage and preservation of meat.
作者
辜雪冬
孙术国
杨飞艳
李北平
杨林
罗章
Gu Xuedong;Sun Shuguo;Yang Feiyan;Li Beiping;Yang Lin;Luo Zhang(Food Science College, Tibet Agriculture & Animal Husbandry University, Nyingchi 860000, China;Faculty of Food Science and Engineering, Center South University of Forestry and Technology, Changsha 410004, China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2019年第16期343-350,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划项目(2018YFD0400102)
西藏自治区重点科研项目“特色农产品加工技术与产品开发”经费资助(XZ201901NA04)
西藏中央支持地方高校发展专项:农畜加工关键技术研发与示范(503118004)
西藏自治区食品科学与工程重点实验室建设项目
西藏农牧学院食品科学与工程学科建设项目
关键词
水分
贮藏
品质控制
牦牛肉
蛋白质二级结构
脂质氧化
moisture
storage
quality control
fresh yak meat
protein secondary structure
lipid oxidation