Tenderness, juiciness, and flavor are the three attributes that describe beef palatability. Tenderness has been shown to be the most important attribute followed by flavor. Research by George et al. (1999) indicated that there is a one in four chance of obtaining a tough steak from a USDA Select grade carcass and a one in five chance for low choice. Post-mortem aging is a well-established practice for tenderizing beef along with improving the flavor. Two types of aging are utilized in the industry, dry and wet, with wet being the most common due to economics. Dry aging meat involves storing unpackaged product in an open-air cooler that has a constant temperature and relative humidity whereas wet aging is in a vacuum-sealed bag stored in refrigerated temperatures. Wet-aged beef commonly has more bloody/serumy and sour flavors whereas dry-aged has beefy, brown-roasted, and overall aged flavor.
The 2010/2011 National Beef Tenderness Survey found that aging times vary in the industry with a range of 1 to 358 d, with close to half (44.2%) of the short loins evaluated aged for less than 14 d. The most frequent range for wet or dry-aged subprimals is between 10-40 days with the majority of the product being aged for 21 days. Aging is more commonly done on products that are of higher quality grades, upper two-thirds USDA Choice and USDA Prime. According to the Agricultural Marketing Service, over 30% of young beef carcasses graded USDA Select in 2011. Limiting loin selection to marbling levels to low Choice and Select (Small50 to Slight50) within the “A” maturity class would encompass approximately 50% of daily harvest. There is limited scientific information on the long-term effects of aging within these selection parameters.
Loins were weighed after each trimming step to calculate the percentage of weight loss due to aging. Aging losses were lowest for wet aged loins compared to dry aged loins (Fig. 1). Dry boneless percentage of weight loss increased as aging period increased, reaching close to 35% weight loss. Odor was assessed on a one to five scale with one having no off-odor and five have an extreme off-odor. Figure 2 shows that DBI and DBL initial odor was higher than the WBI and WBL samples (P = 0.05). It was also found that dry-aged samples had a higher initial odor when compared to the wet-aged samples (P <.0001).
Tenderness improved with increased aging time. Aging type (wet or dry) did not affect the tenderness ratings for all three analyses. Panelists found that as the days of aging increased, the overall aged flavor intensity increased (P= 0.02). Figure 3 shows the significant interaction of wet/dry by bone-in/boneless. Dry boneless steaks had the highest aged flavor, which is expected because a greater amount of lean surface is exposed to oxygen. Panelist found no difference between treatments for beefy flavor and brown-roasted. Wet-aged loins had more bloody/serumy and dry aged more sour notes.
Figure 1. Means for weight loss during aging
Figure 2. Initial odor score LS means for the interaction of days*WD*BIBL. (P = 0.05)
Figure 3. Panelist overall aged flavor LS means (8-point scale) for the interaction of WD*BIBL (P = 0.05)