Investigation of the effects of commercial carcass suspension (24 and 48h) on meat quality in high oxygen modified atmosphere packed beef steaks during chill storage

Effect of VP, MAP and combined packaging systems on the physicochemical properties and microbiological status of veal from unweaned calves

The packaging system is one of the factors influencing the preservation of the nutritional value, microbiological safety, and sensory attributes of meat. The study investigated changes in physicochemical and microbiological properties taking place during 15-day refrigerated storage of two calf muscles, the longissimus lumborum (LL) and semitendinosus (ST), packaged in three systems, respectively, vacuum packing (VP), modified atmosphere packaging (MAP, 80% O2 + 20% CO2), and a combined system (VP + MAP, 8 d in VP followed by 7 d in MAP). LL and ST stored in VP had significantly lower levels of lipid oxidation, higher α-tocopherol content, and higher instrumentally measured tenderness in comparison with the samples stored in MAP. On the other hand, the MAP samples had lower purge loss at 5 and 15 days, a higher proportion of oxymyoglobin up to 10 days of storage, and a better microbiological status. Calf muscle samples stored in the VP + MAP system had intermediate values for TBARS and α-tocopherol content and at the same time were the most tender and had the lowest counts of Pseudomonas and Enterobacteriaceae bacteria at 15 days. All packaging systems ensured relatively good quality of veal characteristics up to the last day of storage. However, for MAP at 15 days of storage, unfavourable changes in colour (a high level of metmyoglobin and a decrease in oxymyoglobin, redness and R630/580 ratio) and in the lipid fraction (a high TBARS value and a significant decrease in α-tocopherol content) were observed.

Oxidative Modification, Structural Conformation, and Gel Properties of Pork Paste Protein Mediated by Oxygen Concentration in Modified Atmosphere Packaging

The objective of this study was to investigate the effect of pork oxidation through modified atmosphere packaging (MAP) on gel characteristics of myofibrillar proteins (MP) during the heat-induced gelation process. The pork longissimus thoracis (LT) was treated by MAP at varying oxygen concentrations (0, 20, 40, 60, and 80% O2) with a 5-day storage at 4 °C for the detection of MP oxidation and gel properties. The findings showed the rise of O2 concentration resulted in a significant increase of carbonyl content, disulfide bond, and particle size, and a decrease of sulfhydryl content and MP solubility (p < 0.05). The gel textural properties and water retention ability were significantly improved in MAP treatments of 0-60% O2 (p < 0.05), but deteriorated at 80% O2 level. As the concentration of O2 increased, there was a marked decrease in the α-helix content within the gel, accompanied by a simultaneous increase in β-sheet content (p < 0.05). Additionally, a judicious oxidation treatment (60% O2 in MAP) proved beneficial for crafting dense and uniform gel networks. Our data suggest that the oxidation treatment of pork mediated by O2 concentration in MAP is capable of reinforcing protein hydrophobic interaction and disulfide bond formation, thus contributing to the construction of superior gel structures and properties.

Intelligent Dynamic Quality Prediction of Chilled Chicken with Integrated IoT Flexible Sensing and Knowledge Rules Extraction

With the enhancement of consumers’ food safety awareness, consumers have become more stringent on meat quality. This study constructs an intelligent dynamic prediction model based on knowledge rules and integrates flexible humidity sensors into the non-destructive monitoring of the Internet of Things to provide real-time feedback and dynamic adjustments for the chilled chicken cold chain. The optimized sensing equipment can be attached to the inside of the packaging to deal with various abnormal situations during the cold chain, effectively improving the packaging effect. Through correlation analysis of collected data and knowledge rule extraction of critical factors in the cold chain, the established quality evaluation and prediction model achieved detailed chilled chicken quality level classification and intelligent quality prediction. The obtained results show that the accuracy of the prediction model is higher than 90.5%, and all the regression coefficients are close to 1.00. The relevant personnel (workers and cold chain managers) were invited to participate in the performance analysis and optimization suggestion to improve the applicability of the established prediction model. The optimized model can provide a more efficient theoretical reference for timely decision-making and further e-commerce management.

Effects of high-oxygen, carbon monoxide modified atmospheres and vacuum packaging on quality of Longissimus thoracis et lumborum steaks from Nellore cows during ageing

Nellore (Bos indicus) cows play an important role in Brazilian beef production. Here, we investigated whether modified atmosphere packaging (MAP) technology could contribute to improving the quality of Nellore cow steaks. To verify this, steaks obtained from Longissimus thoracis et lumborum (LTL) were stored at 2 °C for 28 days using different packaging systems, with one being vacuum and the others being three MAP systems: 75% O₂/25% CO₂ (75%O₂-MAP), 60% CO₂/0.2% CO/39.8% N₂ and 40% CO₂/0.4% CO/59.6% N₂ (0.2%CO-MAP and 0.4%CO-MAP, respectively). Steaks packaged using the CO-MAP showed improved color stability of fresh meat. In turn, the 75%O₂-MAP drastically affected the oxidative stability related to proteins and lipids compared to both anaerobic environments (CO-MAP and vacuum). The CO-MAP increased tenderization and ultrastructural changes when compared to the aerobic MAP without affecting pH, collagen or cooking loss, which were influenced by the storage time. In conclusion, MAP technology may improve the quality and appearance of fresh meat originating from Nellore cows, being a promising alternative for the Brazilian beef industry.

Lipid and Protein Oxidation Marker Compounds in Horse Meat Determined by MIR Spectroscopy

This work broadens the study of lipid and protein oxidation marker compounds in foal meat, employing the technology of Attenuated Total Reflectance-Fourier Transform Mid-Infrared Spectroscopy (ATR-FT/MIR, shortened in the following as MIR). As a main objective, marker compounds from 23 foals were extracted and their absorbance spectra were measured to establish prediction models (calibration and validation) between them and classical quantification analysis of the compounds. Another objective was to ascertain whether a previous extraction of the marker compounds before executing their MIR analysis is preferable compared to direct MIR measurements on the raw meat samples. In this context, marker compound results (TBARS between 0.4387 and 2.1040, and carbonyls between 4.07 and 4.68) showed more consistent predictive models than the ones achieved using quantitative analysis of the spectra obtained from the raw meat. Lipid oxidation compounds predictive models obtained in this work offered an R²_cv of 63.18% and protein oxidation R²_cv obtained in this project showed a value of 54.24%. Thus, MIR technology arises as a promising tool to identify and quantify products derived from lipid and protein oxidation in fresh foal meat.

The effect of the packaging system and storage time on myofibrillar protein degradation and oxidation process in relation to beef tenderness

This study investigated the impact of packaging systems on the degradation and oxidation of beef proteins regarding beef tenderness of longissimus lumborum (LL) and biceps femoris (BF) muscles stored in vacuum skin packaging (VSP), a modified atmosphere with high oxygen concentration (MAP), and combined of these two methods (VSP+MAP). A significant decrease in the Warner-Bratzler shear force (WBSF) in VSP at D14 and D28 for LL was observed compared to BF. A significant effect of packaging system on troponin-T (Tn-T) and desmin degradation was shown (p≤0.001). A high concentration of oxygen in MAP and VSP+MAP affected protein oxidation, which was reflected in myosin oxidative cross-linking. An increase of WBSF values detected in steaks packed in VSP and VSP+MAP systems could be caused by the intensification of protein oxidation. Furthermore, BF was more susceptible to oxidation compared to LL. The VSP+MAP packaging system has resulted in the maintenance of a bright, red color, however has not improved the beef tenderness.

Shelf life of fresh foal meat under MAP, overwrap and vacuum packaging conditions

The objective of this study was to investigate the physico-chemical properties, the microbial counts and the sensory properties' changes of foal steaks packed under various conditions. The experimental packaging systems were: (i) vacuum packaging (VP), (ii) overwrap packaging and (iii) two modified atmosphere packaging methods (MAP): high O₂ MAP (80% O₂+20% CO₂) and low O₂ MAP (30% O₂+70% CO₂). The meat was stored at 2 °C during 14 days and tested for pH, colour, lipid and protein oxidation, microbial counts and sensory assessment of odour, colour and appearance. Of the two MAP, overwrap and VP, both MAP were the most effective treatments for the inhibition of the total viable counts (TVC), Pseudomonas spp., psychrotrophic aerobic bacteria, lactic acid bacteria, Enterobacteriaceae as well as moulds and yeast. According to the sensory evaluation, foal steaks packed under overwrap and MAP treatments resulted unacceptable after 7 days of storage, whereas the vacuum-packed meat was still acceptable. Moreover, the redness value decreased significantly (P<0.001) with all treatments during the storage time, except for the vacuum packs, which increased significantly (P<0.001). Finally, foal steaks from overwrap packaging and MAP conditions had a greater increase of TBAR'S values and carbonyl content during the storage time. High O₂ levels affected foal meat quality negatively, while anaerobic conditions extended the meat's shelf life up to 14 days.

Quality of meat products packaged and stored under vacuum and modified atmosphere conditions

The experimental materials comprised cooked coarsely-ground and finely-ground sausages. The sausages were packaged in vacuum (V) and in modified atmospheres with the following composition: 20 % CO2, 80 % N2 (A1); 50 % CO2, 50 % N2 (A2); 80 % CO2, 20 % N2 (A3). The samples were stored at around 4 °C for 15 days. The measurements were repeated 8 times: at the completion of the production process and at 3-day intervals (day 0, 3, 6, 9, 12, 15) during storage. Drip loss changes in the package were analyzed during storage. Meat products were subjected to a sensory evaluation. The obtained results show that changes in the quality of meat products packaged under modified atmosphere are significantly influenced by the composition of the applied atmosphere. A wider range of quality changes were noted in vacuum-packaged products. Changes in the quality of modified atmosphere packaged products were less significant.