Meat Science最新文献

This study explores the proteolytic activity and meat-tenderizing potential of crude enzyme extracts obtained from the rhizomes of two Zingiber officinale varieties, Roscoe (ZR) and var. rubrum (Zr), tested at different concentrations. The proteolytic activity of all extracts was characterized by using azocasein as a model substrate. Among all tested conditions, the Z. officinale Roscoe sample at an extraction ratio of 0.2 g_FW/mL (ZR_0.2) exhibited the highest catalytic efficiency (V_max/K_M = 129.79), while Zr extracts exhibited lower turnover rates but higher substrate affinity (K_M was down to 0.007 mM). These kinetic results guided the selection of the optimal ginger extract and the most suitable enzyme-to-substrate ratio for meat tenderization. To better understand substrate specificity and hydrolytic efficiency on muscle tissue, the proteolytic kinetics of the selected extract (ZR_0.2) were further assessed using myofibrillar proteins isolated from the Biceps femoris muscle. ZR_0.2 demonstrated superior activity compared to commercial proteases (papain, bromelain), with enhanced degradation of structural proteins and a higher myofibrillar fragmentation index. Marination trials with beef cubes confirmed these results, showing significant improvements in technological parameters such as cooking yield (>90%) and water-holding capacity, while maintaining pH stability. Color analysis revealed greater redness (a* values) in treated samples, both raw and cooked, suggesting a possible antioxidant effect. Sensory evaluation confirmed increased tenderness, juiciness, and chewiness in ZR_0.2-treated meat. Overall, these findings support the use of Z. officinale extracts, specifically ZR_0.2, as selective and multifunctional agents for clean-label meat tenderization, with promising applications for improving the quality and value of beef cuts.

This study demonstrates the suitability of a handheld fluorescence device for the detection of cold chain disruptions (CCDs) of modified-atmosphere packaged minced pork through the package or with unpacked samples. Fluorescence spectra of minced pork stored at a constant temperature of 2 °C were highly correlated with the storage time after processing of the meat. Partial least squares regression (PLSR) models for spectra recorded through the package or for unpacked samples yielded cross-validated R²_CV = 0.90 or 0.95, respectively. Validation with independent samples investigated under controlled conditions resulted in R²_Pred = 0.83 for measurements through the package and 0.88 for measurements of unpacked samples. Unlike the controls, minced pork, which underwent a CCD at 14 °C on storage day 2, was systematically predicted older than its actual storage time depending on the duration of the disruption: 1.1-1.7 d older after a 6-h disruption and with 2.5-3.5 d significantly older after a 12-h disruption. In contrast, CCD-dependent changes of total viable counts (TVC) only appeared on tendency after a 12-h CCD and PLSR predictions of TVC performed inadequately. The storage-time effect detected by fluorescence spectroscopy was apparent already one day after the disruption. The results indicate that fluorescence spectra monitor an ageing process of meat, which is accelerated by a temporarily elevated storage temperature. The comparison of predicted and actual storage time could be useful for a rapid, non-invasive detection of cold chain disruptions and for an assessment of time and temperature effects on the shelf life.

This study investigated the role of a multi-enzyme cascade system in developing the colour of meat products at 10 °C. The system consists of glucose dehydrogenase (GDH) and a fusion enzyme, NOS-YkuN-YumC, which was created through the genetic fusion of the NOS gene to those encoding the flavonoid-binding protein YkuN and the flavonoid reductase YumC. The results showed that recombinant GDH was successfully expressed and purified from Bacillus subtilis 168. The purified GDH exhibited a molecular weight of approximately 32 kDa and a specific activity of 11.40 U/mg, demonstrating high efficiency in nicotinamide adenine dinucleotide phosphate (NADPH) regeneration. Following a 24-h incubation period at 10 °C, the additional supplementation of GDH significantly increased (P < 0.05) the a*-value of the minced meat compared to the NOS-YkuN-YumC alone treatment, whereas no significant difference was observed relative to the nitrite-treated group (P > 0.05). UV-Vis spectroscopy provided further evidence that the incorporation of GDH effectively promoted the formation of nitrosylmyoglobin (NO-Mb). After cooking, the minced meat supplemented with the additional GDH maintained a higher a*-value compared to the sample treated with NOS-YkuN-YumC alone. These results indicated that the addition of GDH promoted NADPH production, which in turn enhanced the catalytic generation of NO by the NOS-YkuN-YumC, thus improving both NO-Mb formation and a*-value in raw meat. And the colour can be stabled in cooked meat. This proof-of-concept study successfully demonstrates the potential of this multi-enzyme cascade system for developing colour in nitrite-free meat products under low-temperature conditions.