This study investigated the effects of different combinations of sous-vide cooking temperature (11, 14 and 17 h) and time (57, 60 and 63 ℃ ) on the eating quality of beef Semimembranous muscle in terms of pH value, internal color of cooked meat, cooking loss, tenderness, and sensory scores. The results showed that as cooking time and cooking temperature increased, the pH value, shear force, cooking loss, L* value, and H* value of bovine Semimembranous muscle all showed an increasing trend, while the a*, b*, C*, and overall sensory score significantly decreased. The cooking loss increased from 28.98% to 33.06% over 11 to 17 hours, and from 27.2% to 36.5% over 57 to 63 ℃ ; the shear force increased from 40.14 to 61.08 N over 57 to 63 ℃ , indicating that as the cooking strength increased, both the water-holding capacity and tenderness decreased. At 57 ℃ and 11 hours, cooked beef had the lowest shear force of 42.58 N, which meets the demand of Chinese consumers for “tender meat”, and the highest scores for overall acceptability and internal color. Therefore, cooking at 57 ℃ for 11 hours can effectively improve the tenderness and water-holding capacity of beef Semimembranous muscles while avoiding some problems such as the reddish color and bland flavor of cooked meat and imparting it with better sensory quality and higher yield.

To address the problem of serious microbial spoilage of dark-cutting (DC) beef, this study investigated the changes in the sensory quality, microbial growth, and volatile organic compounds (VOCs) contents of DC beef during storage under mother packaging (MP) consisting of 80% CO₂ and 20% N₂ or 40% CO₂ and 60% N₂, or vacuum packaging (VP) at chilled (4 ℃ ) or superchilled (-1.5 ℃ ) temperature and subsequent display under high-oxygen modified atmosphere packaging (HiOx-MAP) consisting of 60% O₂ and 40% CO₂ at 4 ℃ . The results showed that during superchilled storage, MP significantly inhibited bacterial growth, reduced the contents of certain VOCs (such as hexanal and 1-octen-3-ol), and thus maintained better odor freshness compared to VP; MP with 80% CO₂ concentration showed higher antibacterial effect, and it significantly reduced the concentration of 3-methyl-1-butanol in displayed DC beef steaks while promoting the formation of some VOCs such as diacetyl and hexanal. After storage under high-CO₂ MP, an off-odor was formed, but it disappeared at 15 min after opening the packaging, which did not cause any adverse effects on the freshness. Both CO₂ concentration and VP affected the change of the microbial community during storage. For all packaging treatments, Carnobacterium was the dominant bacteria after display under HiOx-MAP. The growth of Carnobacterium, Serratia and Leuconostoc may be the main cause of off-odor development in DC steaks throughout the storage and display periods. This study recommends the use of storage with 80% CO₂ MP at superchilled temperature and subsequent display under HiOx-MAP to extend the shelflife of DC beef and inhibit spoilage odor due to microbial growth.