Mitochondrial Tu translation elongation factor (TUFM) has been demonstrated to be involved in cellular autophagy during the postmortem aging of Qinchuan beef. This study aimed to explore the relationship between TUFM expression and changes in energy metabolism during this process. Changes in the expression and content of TUFM, the contents of glucose (GLU), lactic acid (LA), adenosine triphosphate (ATP), adenosine diphosphate (ADP), adenosine monophosphate (AMP), and the activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), triose phosphate isomerase (TPI), malate dehydrogenase (MDH), and cytochrome c oxidase (COX) in the Longissimus dorsi muscle of Qinchuan cattle were determined at different periods (0, 2, 12, 24, 48, 96, 144 and 192 h) of aging at 4 ℃. The results showed that during postmortem aging, the contents of GLU, ATP, ADP and AMP, and the activities of LDH, SDH and TPI exhibited a decreasing trend. Meanwhile, the expression level of TUFM, MDH activity, and the contents of LA and TUFM showed an initial increase followed by a decrease. The activity of COX exhibited an initial decrease followed by a temporary increase and then a decrease. The various indicators of energy metabolism and TUFM exerted their effects mainly at the early stage of postmortem aging. Pearson’s correlation analysis indicated that the expression level of TUFM was significantly positively correlated with MDH and LA but significantly negatively correlated with ATP, ADP, AMP, LDH, SDH, TPI, COX, and GLU at the early stage (P < 0.01). At the middle and late stages, TUFM expression was significantly positively correlated with all these indicators (GLU, LA, ATP, ADP, AMP, LDH, MDH, SDH, TPI and COX) (P < 0.01). In conclusion, during the early period of postmortem aging, the gradual increase of TUFM expression can provide energy to muscle cells for energy metabolism pathways, which may be possibly due to the positive involvement of TUFM in cellular autophagy. When energy is deficient during the middle and late periods, TUFM may inhibit cellular autophagy to prioritize energy use for important pathways (e.g., energy metabolism pathways) other than cellular autophagy, thereby maintaining cellular homeostasis. In summary, TUFM plays a dual role during the postmortem aging process, in regulating cellular autophagy to provide energy for metabolic pathways, thereby assisting in maintaining the duration of post-mortem energy metabolism.

In order to investigate the effect of mitochondrial Tu translation elongation factor (TUFM) expression on the water-holding capacity (WHC) of meat during the postmortem aging of Qinchuan cattle meat, changes in the pH, storage loss, centrifugal loss, cooking loss, and water distribution of the longissimus dorsi of Qinchuan cattle as well as its myofibrillar protein degradation were determined after different aging durations at 4 ℃. Besides, TUFM expression and content as well as beclin 1 expression were examined after 0, 96 and 192 h of aging. The results showed that myofibrillar protein was degraded during the postmortem aging process, and there was a close relationship between the expression of TUFM and beclin1 protein and the WHC of beef. Proteomics revealed consistent changing trends between the expression of TUFM and its content. In general, beclin1 protein expression, storage loss, centrifugal loss, and cooking loss initially increased and subsequently decreased, whereas the opposite was true for pH. Pearson’s correlation analysis showed that the expression of TUFM was highly significantly positively correlated with low-field nuclear magnetic resonance peak area ratio P_2b and beclin 1 protein expression (P < 0.01), significantly positively correlated with storage loss, centrifugal loss, and cooking loss (P < 0.05), highly significantly negatively correlated with P₂₁ (P < 0.01), and significantly negatively correlated with P₂₂ (P < 0.05), but had no significant correlation with pH (P > 0.05). Through proteomics, 23 differential proteins related to TUFM were identified, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that the differential proteins could mediate cellular autophagy by participating in energy metabolism through a variety of pathways. Pearson’s correlation analysis showed that five differential proteins (ATP5F1D, EEF1A2, GSPT1, NDUFB5, and SUCLG1) were significantly correlated with WHC (P < 0.05, P < 0.01). From these analyses, it is clear that there are six proteins including TUFM that affect the WHC of meat by affecting cellular autophagy positively or negatively through various pathways such as energy metabolism and oxygen transport.