Impacts of Various Dry-Aging Methods on Meat Quality and Palatability Attributes of Beef Loins from Cull Cow

ObjectivesBeef from cull cows has been traditionally perceived as low-quality/value meat due to its inferior flavor and tenderness. Given the negative consumer perception of highly processed fresh meat, there is a need to develop a natural post-harvest aging system to improve eating quality attributes of beef products, particularly from cull cows. Dry aging has been practiced for decades as a traditional and natural butchery process, which is also known to improve palatability characteristics. Thus, the main objective of this study was to evaluate the impact of different dry-aging methods on meat quality, microbiological properties and palatability attributes of loins from cull cow beef.Materials and MethodsPaired beef loins from 13 carcasses (Holstein, 30+ mo) were obtained at 5d postmortem, divided into 4 equal length sections and randomly assigned to four aging methods: wet-aging (WA), dry-aging (DA), dry-aging in water permeable bag (DWA) and UV-light dry-aging (UDA; 2 treatment/day, 5 J/s/treatment). Sections were aged for 28d at 2°C, 65% RH and 0.8 m/s air flow. After aging, dry-aged sections (DA, DWA and UDA) were trimmed of dehydrated surface, and trim loss and total saleable yield were recorded. The pH, proximate composition, shear force, water-holding capacity, initial color (instrumental and trained panelist), lipid oxidation (2-thiobabituric acid reactive substances, TBARS), microbial properties (aerobic plate count (APC), lactic acid bacteria (LAB), and yeast and mold (YM) counts) and trained sensory evaluation (11 panelists) were determined. Experimental design was a balanced complete block design. All data were analyzed using PROC MIXED procedure of SAS, and least squares means for all traits were separated (P < 0.05).ResultsDA and UDA had a substantial moisture loss during the aging process, accompanied with higher trim loss compared to other methods (P < 0.05). This resulted in DA having the lowest yield followed by UDA, DWA and WA with the highest saleable yield (P < 0.05). No significant differences were observed on cook loss, WBSF and TBARS between the treatments. DWA had the lowest pH out of all treatments (P < 0.05). UDA had the lowest moisture content and highest drip loss (P < 0.05). Color measurement showed that both DA and WA had significantly higher L* and lower b* values compared to UDA and DWA (P < 0.05). However, a* and lean surface color were not significantly different between the treatments (P > 0.05). For the trim, UDA had the lowest microbial growth among all treatments (P < 0.05). For the lean, UDA had the lowest count for LAB (P < 0.05), WA had the lowest in YM (P < 0.05) and no difference was found for APC between treatments (P > 0.05). Trained sensory panelist found that UDA and WA had higher fat and sour flavor (P < 0.05), and a trend (P = 0.07) of higher oxidized flavor when compared to DWA and DA.ConclusionThe results showed that dry-aging would result in no adverse impact on shear force, cooking loss, initial color and lipid oxidation of mature beef loins. Further, sour and oxidized flavor was lower in dry-aged beef, indicating its potential as value adding process. UV light application minimized microbial growth during dry-aging process, although more analyses are needed to understand its full impact on dry-aged meat quality. Further studies on determining the consumer acceptability as well as flavor-related compound analyses are currently under investigation.

Efficacy of Beef Crust from Dry-Aged Beef Loins as Novel Functional Ingredient

ObjectivesDry-aging is a traditional butchery process, but currently, it has been more practiced in a niche market as a value-adding process. As dry aging involves placing primal/sub-primal sections under a controlled refrigerated condition without packaging materials, the formation of the dried surface (crust) is inevitable due to moisture evaporation. A considerable portion of the crust is to be trimmed off as waste, which is one of the major drawbacks of dry aging. While the beef crust may still exert its functional/technological properties, no information is available regarding the efficacy of utilizing beef crust as a potential food ingredient. Thus, the objective of this study was to determine the physicochemical and functional properties of beef crust from dry-aged beef loins processed under various dry-aging conditions.Materials and MethodsPaired bone-in beef shell loins from 13 cull cow carcasses (C-maturity) were obtained at 5d postmortem, divided into 2 sections and assigned to four aging treatments: wet-aging (WA), dry-aging (DA), dry-aging in water-permeable bag (DWA) and dry-aging under UV-light (UDA; 5 J/s/12 h per day). Beef sections were aged for 28d at 2°C, 65% RH and 0.8 m/s air flow. After aging, the crusts were separated and beef samples from WA and initial (aged for 0 d, INI) were collected for comparison. In three independent batches, the crust samples were freeze-dried and powdered. Moisture contents of samples were measured before lyophilization. Emulsification capacity, salt-soluble protein solubility, emulsifying activity index, and surface hydrophobicity were determined. CIE* color attributes, lipid oxidation (TBARS), and protein oxidation (carbonyl and thiol contents) were measured. The PROC MIXED procedure of SAS was used to analyze the data. Significance level of least square means was set at the confidence level of 95%.ResultsBeef crusts from dry-aged loins had lower moisture contents compared with WA and INI (P < 0.05), while no difference between dry-aging methods was found (P > 0.05). The crust samples had lower L* and chroma values than WA and INI (P < 0.05). Emulsification capacity of DA, DWA, and UDA were lower than WA and INI (P < 0.05), with DA being the lowest (P < 0.05). In general, the crust had a significantly higher salt-soluble protein solubility compared to WA, while no difference between crusts and INI was found (P > 0.05). For emulsifying activity index, DA exhibited higher values than DWA, UDA and WA (P < 0.05), and was comparable to INI (P > 0.05). DA and INI had higher surface hydrophobicity values than the other samples, which could possibly explain the results of emulsifying activity index. A trend of higher TBARS values was found in all dry-aged crusts than WA and INI (P = 0.0688). The crust from dry aging had a higher carbonyl content compared to WA (P < 0.05), while thiol contents were not affected by the treatment (P = 0.1092).ConclusionThe results from the current study indicate that beef crusts exert its functional and technological properties, which could be superior or at least equivalent to wet-aged or unaged beef samples. This study provides novel insight into the potential feasibility and utilization of beef crust from dry-aged beef as a value-added product. Further studies determining the practical application of beef crust as a novel food ingredient (e.g., meat emulsion or beef patty) are in progress.