Search

The aim of this study was to determine the impact of accelerated aging (AA) on shelf stability, product loss, sensory and biochemical characteristics of 2 lower quality beef cuts. Triceps brachii (TB) and semimembranosus (SM) were collected and fabricated from 10 USDA Choice beef carcasses and assigned to 1 of 6 treatments: 3 d cooler aged (control), 21 d cooler aged, AA 49 °C for 2 h, AA 49 °C for 3 h, AA 54 °C for 2 h, and AA 54 °C for 3 h. The results showed that AA can decrease APC counts on steak surface and in purge and redness, but increase lightness and product loss of the steaks (P < 0.01). Lower shear force was also found for AA steaks compared to those from the control (P < 0.01), with the AA 54 °C treatments being comparable to 21 d cooler aging. However, the trained sensory panel determined AA steaks were less juicy and flavorful than those from the control and 21 d cooler aged samples (P < 0.05). There was no off-flavor detected in AA steaks though lipid oxidation was higher in AA samples than those in the control steaks (P < 0.01). The AA treatments stimulated cathepsin activity (P < 0.05), which may have enhanced the solubilization of stromal proteins and led to a different troponin-T degradation pattern compared to those from the 21 d aged samples (P < 0.01). Although AA is an economical and time-efficient method to increase tenderness of lower-quality beef cuts, further research is needed to determine strategies to mitigate the decrease in juiciness from AA treatments., Competing Interests: Declaration of competing interest The authors declare no conflict of interest associated with this research., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Matrix metalloproteinases (MMPs) are responsible for the turnover of intramuscular connective tissue in live animals. We hypothesize that MMPs may play a role in postmortem aging of beef muscles for the degradation of connective tissues. Four different experiments were performed to: 1) characterize MMP activity during postmortem aging of beef; 2) determine if the native beef MMP can contribute to connective tissue degradation in a simulated standard industry postmortem aging condition; 3) explore approaches to improve the native beef MMP activity and 4) characterize MMP activity in beef from cattle supplemented with supranutritional level of Zn. In experiment 1, MMP was active throughout the entire aging periods (3, 21, 42 and 63 d) for beef muscles Longissimus lumborum, Gluteus medius and Gastrocnemius, and the unknown MMP responsible for the collagen degradation was identified as MMP-9 by Western Blot. In experiment 2 and 3, MMP-9 activity was noticeable in the gels after 42 d of storage in the cooler. Moreover, the addition of ZnCl 2 in the model system significantly increased MMP-9 activity when compared to the control (P < 0.01). In experiment 4, Longissimus thoracis from animals supplemented with a supranutritional Zn level had increased Zn availability and MMP-9 activity than those from animals fed with a control diet (P < 0.05). Further research is needed better understand MMP-9 mechanism during postmortem aging of meat. With a better understanding of MMP-9 in the aging process, the beef industry can provide better connective tissue management strategies for lower-quality beef cuts., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest associated with this research., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The aim of this study was to characterize structural and property modifications of intramuscular connective tissue (IMCT) during extended aging. Longissimus lumborum (LL), Gluteus medius (GM), and Gastrocnemius (GT) muscles were collected from 10 USDA choice carcasses, fabricated and assigned to one of four aging periods: 3, 21, 42, or 63 days (n = 120). As expected, tenderness improved, and IMCT texture weakened after 21 days of postmortem aging (dpm; P < 0.05). In addition, transition temperature of collagen decreased (P < 0.01) after 42 dpm. It is interesting to note the collagen structure was also altered where relative % of γ chain decreased after 42 dpm (P < 0.05), and the α1 chain % increased at 63 days (P < 0.01). Finally, The LL and GT had a decrease in the 75 kDa aggrecan fragments from 3 to 21 to 42 dpm (P < 0.05). This study provided evidence that IMCT weakens during postmortem aging due to the modifications of IMCT components such as collagen and proteoglycan., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest associated with this research., (Copyright © 2023. Published by Elsevier Ltd.)

The objective of this study was to elucidate the effect of phospholipase A2 (PLA2) and a PLA2 antibody (aPLA2) on phospholipid (PL) hydrolysis in beef and to understand how the altered PL composition may affect lipid oxidation and antioxidant capacity of beef in an in vitro system. Various combinations of PLA2 and aPLA2 were introduced to a beef liposome model system and exposed to a retail display. The PL and free fatty acid (FFA) profiles, antioxidant capacity and lipid oxidation were measured for the liposome system. Key PL classes were reduced and the release of polyunsaturated FFAs was increased with the inclusion of PLA2 in the treatments (P < 0.05). There was no inhibition of PL hydrolysis with the addition of aPLA2. PLA2 showed strong antioxidant capacity in the liposome system (P < 0.01), but lipid oxidation still increased in samples treated with PLA2 throughout the retail display (P < 0.01). Finally, aPLA2 treatments demonstrated potential to decrease lipid oxidation (P < 0.01)., Competing Interests: Declaration of Competing Interest To the best of our knowledge, the named authors have no conflict of interest, financial or otherwise., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The objective of this study was to evaluate the properties of skin-on and skin-off goat processing and carcasses for processing efficiency, fabrication time, biochemical factors, and sensory attributes for stewed goat meat. Thirty-one goats were harvested in 2 separate experiments, either skin-on (n = 16) or off (n = 15). The carcasses were fabricated into four primals and each primal was cut into cubes. Processing efficiency, carcasses yield, collagen content, moisture, lipid, ultimate pH, and sensory attributes were measured, and multivariate regression analysis were conducted. The skin-on group had greater overall yield compared to the skin-off group (P < 0.01). Consumers rated goat shoulder meat with the highest overall liking compared to the other primals (P < 0.01), regardless of skin present (P > 0.10). Finally, lipid % was found to be the most essential palatability trait to American Asian consumers., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The objective of this study was to identify the relative contribution of tenderness factors for three beef muscles with similar tenderness ratings. Longissimus lumborum (LL), tensor fascia latae (TF) and gastrocnemius (GC) were collected from 10 USDA low Choice beef carcasses and assigned to a 5 or 21 days aging period (n = 60). Sarcomere length, troponin-T degradation, collagen content, mature collagen crosslink density, intramuscular lipid content and trained panel analysis were measured. Correlation and multivariate regression analysis indicated each muscle has a specific tenderness factor that contributed to the overall tenderness evaluated by trained panelists. The equations indicated LL tenderness was driven by lipid content (P < .05); TF tenderness was driven by collagen content (P < .05). GC tenderness was driven by proteolysis (P < .01), and only collagen content can be casually used as an overall tenderness predictor for all three cuts., Competing Interests: Declaration of Competing Interest To the best of our knowledge, the named authors have no conflict of interest, financial or otherwise., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Three chops from 20 pork carcasses were aged for 1, 8, and 21 days. Electrospray ionization-tandem mass spectrometry was used to comprehensively analyze profiles of phospholipids from each sample (n = 60). Total phospholipid quantity decreased 4-folds (P < .01) from 1 to 21 days of aging in pork loins. Phosphatidylinositol (PI) and phosphatidylserine (PS) increased by 30% and 73%, respectively, from 1 to 21 days of aging in pork loins (P < .01). This increase was mainly due to relative percentage increase from PI 38:4 (18:0-20:4) and PS 36:2 (18:0-18:2; P < .01). The results also showed that the relative percentage of lysophosphatidylcholine increased by 35% after short term aging (8d), and phosphatidic acid increased by 10-folds after extended aging (21d; P < .01). These results documented that phospholipids undergo enzymatic hydrolysis during aging, but also indicated that lipid species containing 18:2 or 20:4 within PI and PS were slightly more resistant to enzymatic hydrolysis compared with the other phospholipids., Competing Interests: Declaration of Competing Interest None., (Copyright © 2020 Elsevier Ltd. All rights reserved.)