Postmortem aging is a widely adopted practice in the beef industry to enhance tenderness, palatability, and overall consumer acceptance. It is well-established that refrigerated aging improves meat tenderness by facilitating enzymatic activity that breaks down muscle structure. However, the optimal duration of aging can vary significantly across muscle types due to differences in muscle traits and characteristics. Wet aging involves vacuum-sealing meat in barrier packaging and storing it under refrigerated conditions for an extended period to optimize tenderness and flavor.
As one of the largest agricultural commodities in the United States, beef’s market success is largely driven by flavor, a top consumer preference factor. Although the tenderizing effects of aging are well-documented, the influence of aging duration on beef flavor remains to be fully understood. Recent literature has reported an increase in off-flavor development during extended aging. However, these studies were limited to the Longissimus lumborum. Individual muscles in a beef carcass possess unique biochemical characteristics that influence tenderness and flavor development. Thus, more research is required to fully understand tenderness and flavor development in extended aged beef cuts outside of the middle meats. The objective of this study was to characterize the influence of wet aging on Biceps femoris (BF), Gluteus medius (GM), and Semimembranosus (SM) product performance, sensory attributes, and metabolomics.
Beef carcasses (n = 80) were selected based on Modest marbling (500–599), with paired subprimals allocated to one of eight wet aging durations (14, 28, 35, 42, 49, 56, 63, and 70 days) and stored at 2.2°C ± 1°C. Analysis conducted included: sensory analysis (descriptive and consumer), Warner-Bratzler shear force (WBSF), instrumental color measurements, microbial load, microbiome, lipid oxidation, desmin degradation, volatile compound analysis, and metabolomic and lipidomic profiling. Significance was set at (p<0.05).
Raw color attributes such as redness (a*), yellowness (b*), oxymyoglobin, and deoxymyoglobin varied with aging time, the trends were inconsistent and muscle-specific. Notably, raw SM steaks aged 14 days had higher deoxymyoglobin and chroma values, while 70-day steaks showed lower values for both traits. Lipid oxidation generally increased over time. There were no differences in TBARS values between 14 days and all other aging periods except 56 days for the SM. For the GM and BF, lipid oxidation did not increase significantly after 49 days of aging when compared to 14 days. Additionally, desmin did not degrade further after 49 days for the GM and 35 days for the SM and BF. Throughout the aging process, the microbial load of all three muscles, on average, increased from approximately 2 log CFU/cm2 to 6 log CFU/cm2.
Across all three muscles, consumer sensory ratings for overall liking, flavor, and juiciness did not differ significantly among aging periods. Consumers determined greater tenderness and overall liking for SM steaks aged 56 days compared to all other aging durations. Biceps femoris and GM exhibited consistent consumer ratings across all aging periods. Biceps femoris and GM produced increased off-flavor intensities (liver-like, bitter, sour) generally after 42 or 49 d. BF and GM also showed a decrease in beef flavor identity as aging duration increased. SM exhibited an increase in cardboardy off-flavor intensity, specifically after 28 d aging. For GM and SM steaks, 14 d of age produced the greatest WBSF value compared to all other aging durations. Principal coordinate and partial least squares discriminant analyses distinguished unique sensory profiles among muscles, emphasizing their differential aging responses.
Subtle shifts in the volatile flavor profile and lipidome were observed. The relative abundance of metabolites in both BF and GM increased with increased aging time, regardless of whether the samples were raw or cooked. The SM raw samples had a relative abundant number of metabolites early in aging, with the abundance of metabolites decreasing with increased aging. The relative abundance of metabolites is related to results in flavor scores reported elsewhere. Metabolomics of raw and cooked BF, GM, and SM muscles appear to change in proportion to sensory flavor scores and could be a useful tool to explain flavor differences.
These findings emphasize the need for muscle specific wet aging regiments to ensure a positive eating experience to consumers. These results suggest that extended wet aging beyond the traditional 14 to 21 days can improve instrumental tenderness in certain muscles, such as the SM and GM, without negatively affecting consumer perception of eating quality. Previous works that have demonstrated decreased flavor liking by consumers in products that have been aged for prolonged periods were not supported by the current work. For the beef industry, this indicates an opportunity to add value to lower-tier muscles, such as the SM, through strategic aging, potentially expanding their use in foodservice or retail settings. Importantly, consumer acceptability remained high across all aging periods for all muscles, indicating that longer aging periods do not compromise the eating experience. Overall, extended wet aging had minimal impact on consumer-perceived eating quality but did enhance instrumental tenderness for the SM and GM, indicating potential benefits for product consistency without compromising palatability.
ARMS#010226-05