The impact of muscle and aging time on meat tenderness in the carcasses of Limousin × Holstein-Friesian crossbred bulls

Muscle Proteins, Technological Properties, and Free Amino Acids of Epaxial Muscle Collected from Asian Seabass (Lates calcarifer) at Different Postmortem Durations

The aim of this study was to compare the changes in the epaxial muscle proteins of Asian seabass at two different postmortem durations. The epaxial muscles of Asian seabass were collected 1 h or 24 h postmortem (PM). Whole, ungutted fish were stored in an ice box, with the ice refilled every two hours. The results show significant increases in the MFI values and the contents of solubilized sarcoplasmic proteins, with a molecular weight of proteins of 47 kDa in the 24 h PM samples (p < 0.05). Myofibrillar and alkaline-soluble proteins in the epaxial muscle remained intact 24 h postmortem. Compared with the 1 h PM samples, the 24 h PM meat exhibited lower degrees of expressible water and hardness (p < 0.05), indicating superior water-holding capacity and meat tenderness. However, no differences in springiness or cohesiveness of the cooked meat were observed. Free L-glutamic acid, known as an umami-tasting amino acid, was significantly increased upon the extension of postmortem duration, and its level was above the taste threshold concentration. Overall, the findings indicated that the 24 h PM epaxial muscle of Asian seabass exhibited superior technological properties, along with higher contents of taste-related amino acids.

Differences in toughness and aging potential of longissimus lumborum muscles between Hanwoo cow, bull and steer

Thirty Hanwoo cattle including bulls, cows, and steers (n = 10 each) were slaughtered and investigated for carcass traits (weight, meat color, fat color, yield index, maturity, marbling score, back-fat thickness, and firmness) and meat quality. The meat quality such as: pH, color, cooking loss, fatty acid, thiobarbituric acid reactive substance, warner-bratzler shear force, tensile tests, and texture profiles were analyzed on longissimus lumborum (LL) muscles of the carcasses at different aging times (3 d and 21 d). The results showed that steers and cows had higher back-fat thickness and marbling score, and a lower firmness (p < 0.001) than bulls. Bulls exhibited a lower meat quality indicating by higher cooking loss, thiobarbituric acid reactive substance content, warner-bratzler shear force and tensile test values (p < 0.01). Regarding the sensory property, the bull meat also had higher hardness, and lower tenderness, juiciness and flavor scores than the cow or steer meat (p < 0.01). Additionally, the bull meat had a higher polyunsaturated fatty acid and a lower monounsaturated fatty acid contents (p < 0.01). With increased aging time, the meat tenderness was improved in all the genders. Taken together, the present study demonstrated that the gender and aging time affected the carcass traits, fatty acid and sensory quality of beef. Postmortem aging could improve the meat tenderness of all genders especially bulls.

Effects of alternating electric field assisted freezing-thawing-aging sequence on longissimus dorsi muscle microstructure and protein characteristics

The current study investigates the influence of alternating electric field (AEF)-assisted freezing-thawing-aging sequence on the muscle microstructure and myofibrillar protein characteristics. Three treatments were used for longissimus dorsi (LD) muscle: only aging (OA), freezing-thawing-aging sequence (FA) and AEF-assisted freezing-thawing-aging sequence (EA). Compared with the FA and EA groups, the OA group showed considerably fewer cracks between muscle fibers and maintained the integrity of the Z-line as observed using scanning and transmission electron microscopy, respectively. Furthermore, the EA treatment effectively decreased myofibrillar fragmentation, myofibrillar protein aggregation, and protein oxidation, as shown by the myofibrillar fragmentation index, turbidity, and total sulfhydryl concentration. Analysis of surface hydrophobicity and the Fourier transform infrared, UV absorption, and fluorescence spectrums indicated that AEF minimized the alterations of protein secondary and tertiary structure alterations during aging after freezing.

The Effects of Postmortem Time on Muscle Trout Biochemical Composition and Structure

Fish industry operators have to process fish that arrive at various postmortem times. Postmortem time constrains processing and impacts product quality, safety, and economic value. The objective identification of biomarkers is desirable to predict the postmortem day of aging and this requires a comprehensive longitudinal characterisation of postmortem aging. We analysed the postmortem aging process in trout over a 15-day window. Quantitative physicochemical measurements (pH, colour, texture, a_w, proteolysis, and myofibrillar protein solubility) performed on the same fish over time revealed the levels of protein denaturation, solubility, and pH, among other parameters, change very little when assessed by conventional chemical methods. Histological analyses were performed on thin sections and revealed fibre ruptures after 7 days of storage on ice. Ultrastructures were observed by transmission electronic microscopy (TEM) and revealed that sarcomere disorganisation occurred more often after 7 days of storage. Label-free FTIR micro-spectroscopy combined with a SVM model accurately predicted the postmortem time. Spectra-based PC-DA models also enable the identification of biomarkers corresponding to Day 7 and Day 15 postmortem. This study provides insights on postmortem aging and raises prospects for the rapid assessment of trout's freshness status from label-free imaging.

Influence of Plant Extract Addition to Marinades on Polycyclic Aromatic Hydrocarbon Formation in Grilled Pork Meat

Marinating is one of the most common methods of pre-processing meat. Appropriate selection of marinade ingredients can influence the physicochemical properties of the meat and can reduce the level of polycyclic aromatic hydrocarbons (PAHs) in the final product. The effects of the inclusion of natural plant extracts such as bay leaf (BL), black pepper (BP), turmeric (TU), jalapeno pepper (JP) and tamarind paste (TA) in marinades on the physicochemical properties of grilled pork neck were studied. The addition of spice extracts to marinades increased the proportion of colour components L* and b*. The use of TU, TA, JP, MX and C marinades lowered the hardness and pH of the meat. The highest phenolic compound levels were observed in the case of the mixture of all extracts (MX) and JP marinades, and the highest total antioxidant capacity was exhibited by the BL and MX marinades. The highest PAH content was recorded in the CON marinade (Σ12PAH 98.48 ± 0.81 µg/kg) and the lowest in the JP marinade (4.76 ± 0.08 µg/kg), which had the strongest, statistically significant reducing effect (95% reduction) on PAH levels. Analysis of correlation coefficients showed a relationship between the total antioxidant capacity of the marinades and the PAH content in grilled pork.

Effect of sous vide cooking and ageing on tenderness and water-holding capacity of low-value beef muscles from young and older animals

This study investigated the effect of the age of the animal, sous vide cooking and ageing on tenderness and water-holding capacity of bovine biceps femoris (BF) and semitendinosus (ST). Samples of each muscle from young (<18 months) and older (30-42 months) animals, at 0 and 13 days ageing, were cooked at 55 °C, 65 °C, and 75 °C for 1 h, 8 h and 18 h and tested for Warner-Bratzler shear force (WBSF), cooking loss, total water content and collagen solubility. WBSF reduced with ageing (P < 0.05) and sous vide cooking (P < 0.001) in both muscles. Our results demonstrated that meat from older animals required a higher temperature (75 °C) and prolonged cooking (18 h) to achieve equal tenderness in both BF and ST relative to young animals. Cooking time, temperature and their interaction altered cooking loss (P < 0.001) for both muscles. The higher cooking temperature increased collagen solubility (P < 0.001) in both muscles and solubilisation of collagen may have contributed to improved tenderness of BF and ST in sous vide cooking.