Ultimate pH effects on dry-aged beef quality

Widely Targeted Metabolomic Analysis Reveals Dynamic Metabolic Changes in Yanbian Cattle during Dry-Aging Process

Dry-aging is a postmortem process that can substantially enhance the texture and flavour of beef. This study entailed suspending Yanbian cattle M. gluteus medius in the aging cabinet, maintained at a temperature of 2-4 °C and a relative humidity of 85 ± 5% for 35 days. Throughout this period, samples were systematically collected every 7 days. The widely targeted metabolomic analysis has been used in this investigation to analyse the dynamic changes in Yanbian cattle metabolites during dry-aging. A total of 883 metabolites were identified, with amino acids and their metabolites representing the largest proportion. Multivariate statistical analysis showed that 373 metabolites were identified as differential metabolites that changed significantly during the dry-aging process, including metabolites of amino acids, glycerophospholipids, and nucleotides and their metabolites. Additionally, 308 metabolites exhibited various increasing trends with time in dry-aging. The analysis of KEGG pathway analysis showed that ABC transporters, glycerophospholipid, and arachidonic acid metabolism are the most important metabolic pathways during dry-aging. These findings can guide technological developments in the meat processing sector and provide valuable insights into the metabolic traits and pathways of Yanbian cattle during the dry-aging process.

Liquid Chromatography-Mass Spectrometry-Based Metabolomics Reveals Dynamic Metabolite Changes during Early Postmortem Aging of Donkey Meat

BACKGROUND

Metabolic changes in donkey meat during the early postmortem period have not been previously reported.

METHODS

The LC-MS-based metabolomics technique was conducted to understand the metabolic profiles and identify the key metabolites of donkey meat in the first 48 h postmortem.

RESULTS

The pH values showed a decreasing trend followed by an increasing trend. Shear force was the lowest at 4 h and the highest at 24 h (p < 0.05). For the metabolome, some candidate biomarker metabolites were identified, such as adenine, inosine, n-acetylhistidine, citric acid, isocitrate, and malic acid. Predominant metabolic pathways, such as citrate cycle (TCA cycle), alanine, aspartate and glutamate metabolism, and purine metabolism, were affected by aging time. Overabundant n-acetylhistidine was identified in LT, declined at 12 h postmortem aging, and then increased. This may explain the significantly lower pH at 12 h postmortem. Adenine was higher at 4 h postmortem, then declined. Decreased ADP may indicate a fast consumption of ATP and subsequent purine metabolism in donkey meat.

CONCLUSIONS

The results of this study provided new insights into early postmortem aging of donkey meat quality.

Study on Ways to Improve the Quality of Black Goat Meat Jerky and Reduce Goaty Flavor through Various Spices

In this study, we analyzed the physicochemical and sensory properties of black goat jerky marinated with various spices (non-spice, control; rosemary, RO; basil, BA; ginger, GI; turmeric, TU; and garlic, GA). The physicochemical properties of black goat jerky analyzed were pH, water holding capacity, color, cooking yield, shear force, and fatty acid composition. The sensory characteristics were analyzed through the aroma profile (electronic nose), taste profile (electronic tongue), and sensory evaluation. The pH and water holding capacity of the GI showed higher values than the other samples. GI and GA showed similar values of CIE L* and CIE a* to that of the control. The shear force of the GI and TU was significantly lower than that of other samples (p<0.05). Regarding fatty acid composition, GI showed high unsaturated and low saturated fatty acid contents compared with that of the other samples except for RO (p<0.05). In the aroma profile, the peak area of hexanal, which is responsible for a faintly rancid odor, was lower in all treatment groups than in the control. In the taste profile, the umami of spice samples was higher than that of the control, and among the samples, GI had the highest score. In the sensory evaluation, the GI sample showed significantly higher scores than the control in terms of flavor, aroma, goaty flavor, and overall acceptability (p<0.05). Therefore, marinating black goat jerky with ginger powder enhanced the overall flavor and reduced the goat odor.

Microbiota associated with commercial dry-aged beef in France

Meat dry aging consists in storing unpackaged meat in a cold room, and at a specific and controlled relative humidity (RH), for a period of 1 to 5 weeks or more. This practice has become widespread in recent years due to its positive effect on the tenderness of the meat but also on other organoleptic characteristics and therefore its market value. The objective of this work was to study the bacterial and fungal microbiota of dry-aged beef at the commercial stage by both culture-dependent and -independent approaches. Fifty-eight samples of dry-aged meat from different producer types (meat processing plants, artisanal and supermarket butchers) were studied. The dry-aging conditions (temperature, RH) of the meats, as well as the surface pH and aw, were measured. The main microbial groups were enumerated by culture on various dedicated media. Concerning fungi, isolates of yeasts and molds (n = 257) were identified after dereplication by FTIR spectroscopy and/or sequencing of taxonomically relevant genes (26S rDNA, ITS, β-tubulin, actin). Metagenetic analyzes targeting the V3-V4 regions of 16S rDNA and ITS2 were also performed. Overall, ripening practices were diversified with temperatures and RH between 0.5 and 2.8 °C (median = 2 °C) and 47 and 88 % (median = 70 %), respectively. The aerobic colony count varied between 1.97 and 10.91 log10 CFU/g (median = 8.32 log10 CFU/g) and was similar to that of Pseudomonas spp., indicating that this bacterial group was dominant. Yeast populations varied between <2 and 9.41 log10 CFU/g, while molds showed abundances between <2 and 7.7 log10 TFU/g, the highest values being found in meats matured with a high RH. Bacterial and mold counts were positively correlated with the dry-aging RH and, to a lesser extent, temperature. The main yeast species were Candida zeylanoides and Yarrowia alimentaria as well as Itersonilia pannonica (identified only in metagenetics). The dominant mold species were psychrophilic or psychrotrophic species, namely Mucor complex flavus and Helycostylum elegans/pulchrum that have already been shown to be associated with dry-aged beef meat. This study has identified the main microorganisms associated with dry-aged meat in France, which raises the question of their role in the organoleptic quality of these higher value products.

Effect of glycolysis on water holding capacity during postmortem aging of Jersey cattle-yak meat

BACKGROUND

Postmortem muscle moisture loss leads to a decrease in carcass weight and can adversely impact overall meat quality. Therefore, it is critical to investigate water holding capacity (WHC) to enhance meat quality. Current research has primarily focused on examining the correlation between signaling molecules and meat quality in relation to the glycolysis effect on muscle WHC. But there exists a significant knowledge gap regarding the mechanism of WHC in Jersey cattle-yak meat.

RESULTS

Jersey cattle-yak meat pH decreased and then increased during postmortem aging. Lactate content, cooking loss, pressing loss, drip loss and centrifuging loss of Jersey cattle-yak meat increased and then decreased during postmortem aging. The glycogen content of Jersey cattle-yak meat was significantly higher than that of yak meat at 6-120 h, being 8.40% higher than that of yak meat at 120 h. The activity of key glycolytic enzymes hexokinase (HK), pyruvate kinase (PK), phosphofructokinase (PFK) and lactate dehydrogenase (LDH) in Jersey cattle-yak meat was lower than that in yak meat. Correlation analysis showed that Jersey cattle-yak meat WHC was positively correlated with the activity of HK, PK, PFK and LDH.

CONCLUSIONS

The WHC of Jersey cattle-yak meat was higher than that of Gannan yak meat, and it was significantly positively correlated with the activity of key enzymes of the glycolytic signaling pathway. Therefore, the glycolysis rate can be reduced by inhibiting enzyme activity to improve Jersey cattle-yak meat WHC and meat quality. © 2023 Society of Chemical Industry.

Development of innovative antioxidant food packaging systems based on natural extracts from food industry waste and Moringa oleifera leaves

Active packaging that prolongs food shelf life, maintaining its quality and safety, is an increasing industrial demand, especially if integrated in a circular economy model. In this study, the fabrication and characterization of sustainable cellulose-based active packaging using food-industry waste and natural extracts as antioxidant agents was assessed. Grape marc, olive pomace and moringa leaf extracts obtained by supercritical fluid, antisolvent and maceration extraction in different solvents were compared for their antioxidant power and phenolic content. Grape and moringa macerates in acetone and methanol, as the most efficient and cost-effective extracts, were incorporated in the packaging as coatings or in-between layers. Both systems showed significant free-radical protection in vitro (antioxidant power 50%) and more than 50% prevention of ground beef lipid peroxidation over 16 days by indirect TBARS and direct in situ Raman microspectroscopy measurements. Therefore, these systems are promising for industrial applications and more sustainable farm-to-fork food production systems.

The effect of succinate on color stability of Bos indicus bull meat: pH-dependent effects during the 14-day aging period

Bos taurus indicus bulls are very susceptible to pre-slaughter stress, which directly impacts the decline in muscle pH, leading to darker meat. The aim was to investigate the effect of succinate and atmosphere on the color stability of Nellore (Bos taurus indicus) Longissimus lumborum steaks classified by ultimate pH (pHu): normal pHu (5.40 ≤ pHu ≤ 5.79) and high pHu (pHu ≥ 5.80). The experimental treatment systems were: (i) vacuum packaging without succinate injection, (ii) HiOx-MAP (80 % O2 + 20 % CO2), and (iii) HiOx-MAP (80 % O2 + 20 % CO2) enhanced with sodium succinate injection (pH 5.4). Steaks from all treatment systems were stored at 4 °C for 14 days and tested for instrumental color, myoglobin content, oxygen consumption (OC), metmyoglobin-reducing activity (MRA), lipid oxidation, and microbiological analysis. High and normal pHu vacuum-packaged steaks exhibited greater color stability due to higher MRA. High and normal pHu steaks packaged with HiOx-MAP or HiOx-MAP enhanced with succinate showed improved color due to lower deoxymyoglobin content (%DMb) and OC up to the eighth day of storage. Still, succinate injection promoted increased (P < 0.05) lipid oxidation in normal pHu steaks and reduced MRA after 14 days. These findings emphasize the intricate interplay between pHu and packaging systems on Bos taurus indicus meat quality. Further research in this area could contribute to a better understanding of meat color abnormalities and provide insights into potential meat preservation and enhancement strategies.

Microbial, Physicochemical Profile and Sensory Perception of Dry-Aged Beef Quality: A Preliminary Portuguese Contribution to the Validation of the Dry Aging Process

Beef dry-aging consists of a selection of unpackaged prime cuts placed in a controlled environment cold room for several weeks. The goals are to concentrate flavors like nutty and beefy and to improve tenderness. The aim of this study was to verify the microbiological and physicochemical behavior and sensory perception of meat during a sample process example of meat dry-aging. Twelve beef loins were selected for 90 days of dry aging and placed in a cold room with average temperature, relative humidity and forced air 3.2 ± 0.7 °C, 60.7 ± 4.2% and 0.5-2 m/s, respectively. Samples of crust and lean meat were collected on days 1, 14, 21, 35, 60 and 90 of the dry aging process for microbiological, physicochemical (pH, aw, color L*a*b*) and sensory analysis. During drying, no pathogenic bacteria were detected, and the average counts were higher for the crust. The average values for water activity (aw) and pH were 0.98 ± 0.02 and 5.77 ± 0.015, respectively. A slight decrease in aw and an increase in pH were observed over the aging period (p < 0.05). The lower microbial counts on the lean meat and the overall assessment of freshness confirm the importance of good manufacturing and storage practices during dry aging.

Effect of ultimate pH on quality of aged Longissimus dorsi muscle of Zebu Nellore (Bos indicus) during long-term frozen storage

Despite the relatively high occurrence of bovine meat with intermediate to high ultimate pH (pHu), there is a lack of studies focused on the effects of long-term conventional air-blasting freezing storage on quality parameters of commercial beefs of Zebu Nellore (Bos indicus) with varying pHu ranges. The objective of this work was to evaluate the influence of pHu ranges [normal (≤5.79), intermediate (5.80 to 6.19), and high (≥6.20)] and long-term frozen storage on quality parameters of aged Longissimus dorsi beefs of Zebu Nellore (Bos indicus). The aging conditions were set at 2 °C for 14 days, while the freezing conditions were set at - 20 °C, and samples were collected after 3, 6, 9, and 12 months of storage. The results indicated that the pHu influenced meat quality parameters, as well as the chemical forms of myoglobin, which changed throughout the frozen storage, leading to a brighter red color, especially for the normal pHu beef samples, likely due to increased oxymyoglobin content. Frozen storage improved tenderness, with high pHu beef samples being the more tender after 12 months, potentially due to lower protein oxidation, as measured by the carbonyl content. Increased drip loss was observed over freezing time, with a concomitant decrease in protein solubility, especially for myofibrillar and sarcoplasmic proteins, which differed among the pHu ranges. These findings are valuable for determining freezing time as a preservation strategy to maintain beef quality within different pHu ranges.

Metabolic and microbial analyses of the surface and inner part of wet-aged and dry-aged beef

The effects of aging and microbial growth on the metabolome of aged beef were investigated in this study. The metabolome of beef is influenced by the aging method applied. This includes the aging-related changes in metabolism and the presence of microorganisms on the beef during aging that may affect the beef and its quality. The inner part and the trimmed surface of dry-aged (the surface of dry-aged beef is also called the "crust" due to its drying during aging) and wet-aged beef were analyzed by 1 H nuclear magnetic resonance (NMR) spectroscopy over aging periods up to 28 days at intervals of 7 days, and the former also by microbiological analysis. The metabolome detected by 1 H NMR spectroscopy demonstrated changes over the aging time of beef and differed depending on the sampling location (surface or inner part of beef). The influence of the microbiota on changes in the metabolome can be negligible due to the low microbial growth on the surface of dry-aged beef (<3 log CFU/g). Therefore, the aging-related metabolism postmortem of the analyzed dry-aged beef might be the main factor for metabolic changes. The significantly (p < 0.05) higher amino acids and inosine concentrations and lower inosine 5'-monophosphate concentrations suggested enhanced protein degradation and energy metabolism in the wet-aged beef compared to the dry-aged beef, probably due to the combined influence of the aging and the microbiota on the wet-aged beef and, thus, its metabolic changes.

Characterization and Correlation of Dominant Microbiota and Flavor Development in Different Post-Mortem Processes of Beef

Post-mortem aging could enhance the unique flavors of beef via several biochemical pathways. The microbiota is one of the important factors in the flavor development of aging beef, but their potential relationship has rarely been studied. This study characterized the apparent meat quality, flavor profiles, and microbial communities of beef during the different post-mortem processes, followed by the investigation of the correlations between the dominant microbiota and key volatile compounds. The results showed that wet-aged beef has a higher product yield and more stable color than dry-aged beef, as evidenced by the significantly lower value of aging loss and discoloration (ΔE). According to the odor activity value, 11 out of 65 compounds were categorized as aroma-active components, and 9 of them, including 1-pentanol, 1-octen-3-ol, hexanal, nonanal, heptanal, octanal, 2-nonenal, (E)-, 2-octenal, (E)- and 2-decenal, (E)-, were enriched in beef wet-aged for 7 d. Significant variances were found in the microbial communities of different aging beef. Of these, 20 microbiota (with 10 bacterial and 10 fungal genera) were recognized as the dominant genus. Partial least squares regression combined with a correlation network model revealed that five microbial genera, including Trichosporon, Prauserella, Rhodotorula, Malassezia, and Corynebacterium, constituted the functional microbiota responsible for flavor formation in aging beef and were positively associated with ≥7 key volatile compounds (p < 0.05, |ρ| > 0.7). This study suggests that the application of wet aging within 7 d on beef is better for meat quality and provides novel insights into the mechanisms of flavor formation in post-mortem aging beef via functional microbiota.

Influence of Ageing Time and Method on Beef Quality and Safety

The effectiveness of dry ageing with regard to retaining meat quality is still subject to debate. At 4 d post mortem, samples of boneless strip loins were excised from young Charolais carcasses and then stored for a further 26 d in a cooler, either vacuum-packaged (VP) or dried-aged (DA). Loin samples were also dissected 7 d post mortem as a control treatment (CT). Chemical, instrumental and microbiological data (n = 18) were determined in longissimus dorsi and underwent ANOVA to estimate the differences in the ageing fixed factor split into two orthogonal contrasts: control vs. aged and VP vs. DA. Ageing loss (both surface dehydration and water purge) was greater in DA compared to VP samples, resulting in the lowest moisture content and highest crude protein and fat percentage in DA loins. The ageing method did not affect meat surface colour, except for redness, which had the lowest value in DA samples. Meat tenderness improved a similar amount following both VP and DA ageing treatments. Compared to the control, prolonged ageing raised both the peroxide value and the total microbial count, especially in DA samples, though both remained within the recommended limits. In summation, both ageing methods improved beef meat tenderisation, preserving its shelf life.

Effects of in-the-bag dry-ageing on meat quality, palatability and volatile compounds of low-value beef cuts

This study evaluated the effects of in-the-bag dry-ageing (BDA) (21 and 42 d) on meat quality, palatability, and volatile compounds of clod heart, brisket, and flat iron cuts from steers. In all cuts, BDA increased moisture losses (P < 0.05), but this did not reduce the juiciness of 21 d BDA versus wet-aged (WA) steaks. In clod heart, BDA increased overall tenderness at 21 d compared to 21 d WA (P < 0.01). Regardless of ageing period, BDA of clod heart increased beef flavour and salty taste and decreased sour-dairy and stale/cardboard flavours and concentrations of volatile compounds derived from lipid oxidation compared to WA (P < 0.05). In brisket, BDA increased salty taste and fatty aroma and reduced bloody/serumy flavour, whereas decreased beef and buttery flavours and intensified some unpleasant aromas/flavours (P < 0.05) for both ageing periods. The BDA of flat iron increased several undesirable aromas/flavours and decreased sweet taste and beef and buttery flavours (P < 0.05), regardless of ageing period. Overall, BDA for 42 d decreased meat quality and palatability and increased concentrations of volatile compounds from lipid oxidation, especially in flat iron cuts. Value could be recovered by customizing BDA periods by cut.

Influence of meat sample geometry on dehydration dynamics during dry-aging of beef

Meat geometry may impact on the dehydration kinetics during dry-aging influencing the drying rate and, potentially, aspects of meat quality. In this study, three meat geometries (slices, steaks and sections) were prepared from three bovine Longissimuss thoracis et lumborum at 3 days post-mortem and were dry-aged at 2 °C, 75% relative humidity with an airflow of 0.5-2.0 m/s for 22 days (slices), 48 days (sections) and 49 days (steaks). Weights were recorded during dry-aging and drying curves were obtained for the three geometries, with the larger sections showing limited dehydration due to internal resistance to moisture migration from the core to the surface. Seven thin-layer equations were fitted to the dehydration data in order to model the drying kinetics during dry-aging. Thin-layer models described reliably the drying kinetics of the three geometries. In general, reduced k values (h^-1) reflected the lower drying rates as thickness increased. The Midilli model provided the best fit for all geometries. Proximate analyses of the three geometries and bloomed colour of sections were measured at the start and the end of the dry-aging period. Moisture loss during dry-aging led to the concentration of protein, fat and ash contents; while no significant differences were found for L*, a* and b* values of sections before and after the dry-aging process. In addition, moisture content, water activity (a_w) and LF-NMR measurements were taken at different locations within beef sections to further explore water dynamics during dry-aging.

Fungal Biostarter Effect on the Quality of Dry-Aged Beef

Meat aging is a process consisting of its storage in specific conditions which leads to an increase in its organoleptic qualities. The most common method of meat aging is the wet vacuum-bag based method, whereas the traditional method, called dry-aging, involves keeping meat at a low temperature for an extended time. However, this process is characterized by low repeatability of the results. Therefore, different approaches to stabilize the process are tested. The aim of this study was to analyze the influence of the Mucor flavus biostarter on the physicochemical characteristics and sensory quality of dry-aged beef (DAB). We hypothesized that a fungal biostarter positively influences the quality of DAB and stabilizes the dry-aging process. Meat control samples (N = 7) and samples inoculated with the Mucor flavus biostarter (N = 7), originating from 14 individuals crossbred from Holstein-Friesian cows with bulls of meat breeds, were put into the dry-aging fridge (DryAger, Bad Saulgau, Germany) for 28 days. The physicochemical parameters (pH, color parameters, WHC, GP (glycolytic potential), chemical composition of muscle, the content of malondialdehyde, shear force), muscular protein proteolysis (SDS-PAGE), sensory quality, and microbial composition of DAB were assessed after aging. The results showed a significant effect of the fungal biostarter on pH increase (0.25 units), and light myosin chain proteolysis (approximately 16%) as well as improvement of sensory quality (e.g., acceptability was improved by one unit in an applied scale 1-9). All together, the M. flavus-based biostarter was shown to increase the quality of DAB.

Microbiological safety of aged meat

The impact of dry-ageing of beef and wet-ageing of beef, pork and lamb on microbiological hazards and spoilage bacteria was examined and current practices are described. As 'standard fresh' and wet-aged meat use similar processes these were differentiated based on duration. In addition to a description of the different stages, data were collated on key parameters (time, temperature, pH and aw) using a literature survey and questionnaires. The microbiological hazards that may be present in all aged meats included Shiga toxin-producing Escherichia coli (STEC), Salmonella spp., Staphylococcus aureus, Listeria monocytogenes, enterotoxigenic Yersinia spp., Campylobacter spp. and Clostridium spp. Moulds, such as Aspergillus spp. and Penicillium spp., may produce mycotoxins when conditions are favourable but may be prevented by ensuring a meat surface temperature of -0.5 to 3.0°C, with a relative humidity (RH) of 75-85% and an airflow of 0.2-0.5 m/s for up to 35 days. The main meat spoilage bacteria include Pseudomonas spp., Lactobacillus spp. Enterococcus spp., Weissella spp., Brochothrix spp., Leuconostoc spp., Lactobacillus spp., Shewanella spp. and Clostridium spp. Under current practices, the ageing of meat may have an impact on the load of microbiological hazards and spoilage bacteria as compared to standard fresh meat preparation. Ageing under defined and controlled conditions can achieve the same or lower loads of microbiological hazards and spoilage bacteria than the variable log10 increases predicted during standard fresh meat preparation. An approach was used to establish the conditions of time and temperature that would achieve similar or lower levels of L. monocytogenes and Yersinia enterocolitica (pork only) and lactic acid bacteria (representing spoilage bacteria) as compared to standard fresh meat. Finally, additional control activities were identified that would further assure the microbial safety of dry-aged beef, based on recommended best practice and the outputs of the equivalence assessment.

Dietary Inclusion of Defatted Silkworm (Bombyx mori L.) Pupa Meal for Broiler Chickens at Different Ages: Growth Performance, Carcass and Meat Quality Traits

The present study was conducted to assess the effects of a 4% defatted silkworm (SWM-DEF) meal dietary incorporation into chickens’ diet at different growth stages on growth performances, carcass, and meat quality traits. A total of 90 Ross 308 one-day-old male broiler chickens were randomly allocated into 3 dietary groups of 5 replicated pens/diet (6 chickens/pen). One group was fed a standard soybean-based diet (C); group SWM1 consumed a starter diet (1−10 days of age) including 4% SWM-DEF and then the C diet up to slaughter (11−42 days of age); group SWM2 was fed with the C diet in the starter phase and the 4% SWM-DEF diet up to slaughter. Individual live weight and pen feed intake were determined at the end of each feeding phase: starter, grower, and finisher. Weight gain and FCR were then calculated. At 42 days of age, chickens were slaughtered and carcass traits determined. Leg and breast physico-chemical meat quality was also evaluated. Results confirmed that SWM-DEF could be a possible alternative feed source for chickens since growth performance, carcass, and meat physical traits were overall comparable in the three treatment groups. The feeding stage seemed to play a relevant impact on the sole meat protein content (SWM1 < SMW2 and C; p < 0.001). Concluding, the results available to date indicate that 4% SWM-DEF can be provided to chickens in different growth phases, and the choice of the inclusion period is more an industrial cost-benefit evaluation. From the scientific point of view, however, an administration in the grower-finisher phase rather than in the starter one provided the best meat nutritional quality. Further investigations should focus on the impact on meat fatty acids profile and sensory traits, which are of utmost importance for consumers.

Microbial diversity of meat products under spoilage and its controlling approaches

Meat spoilage (MS) is a complex microbial ecological process involving multiple specific microbial interactions. MS is detrimental to people's health and leads to the waste of meat products which caused huge losses during production, storage, transportation, and marketing. A thorough understanding of microorganisms related to MS and their controlling approaches is a necessary prerequisite for delaying the occurrence of MS and developing new methods and strategies for meat product preservation. This mini-review summarizes the diversity of spoilage microorganisms in livestock, poultry, and fish meat, and the approaches to inhibit MS. This would facilitate the targeted development of technologies against MS, to extend meat's shelf life, and effectively diminish food waste and economic losses.

Effects of Chitosan/Collagen Peptides/Cinnamon Bark Essential Oil Composite Coating on the Quality of Dry-Aged Beef

The aim of this study was to evaluate the effects of the chitosan/collagen peptides/cinnamon bark essential oil composite coating on dry-aged beef. Chitosan (2%, w/v), collagen peptides (1%, w/v), and cinnamon bark essential oil (1%, v/v) were homogenized to obtain the coating. Beef samples were divided into three groups (traditional dry-ageing, in-bag dry-ageing, and coating and then dry-ageing) and dry-aged for 42 days. Physiochemical, microbial, and sensorial parameters of samples were determined during the dry-ageing process. There were no significant differences (p > 0.05) in pH values, shear force values, cooking loss, color, juiciness, tenderness, and flavor across groups. The total volatile base nitrogen value of the coating group was lower than those of the other two groups. Compared to traditional dry-ageing, in-bag and coating dry-ageing reduced (p < 0.05) many volatile compounds such as alcohols, aldehydes, ketones, and acetate. In-bag and coating dry-ageing had no impact on the fungal community, but changed the bacterial community by inhibiting Pseudomonas. This study demonstrates that the chitosan/collagen peptides/cinnamon bark essential oil coating reduces microbial spoilage during dry-ageing, and has a small influence on product quality.

The effect of storage method on selected physicochemical and microbiological qualities of wild boar meat

BACKGROUND

This study investigated the influence of the storage method on the physicochemical characteristics and microbial growth of m. longissimus thoracis et lumborum (LTL), m. biceps femoris (BF) and m. vastus lateralis (VL) of wild boar. Muscles were stored in a vacuum (VAC), in a modified high-oxygen atmosphere (MAP) or meat seasoning cabinet (DRY-AGED) for 21 days.

RESULTS

Wild boar meat was characterised by a high protein and low fat content and a good amount of potassium, sodium, calcium, magnesium, zinc and iron. Significantly higher (P < 0.05) pH values were noted for DRY-AGED muscles stored for 21 days (up to 5.89 for VL). On day 21, a significant decrease in pH was noted for all MAP muscles (down to 5.23 for BF). Storage losses due to desiccation and water loss were significantly higher for DRY-AGED samples and ranged from 25.63% to 32.89% on day 21. MAP affected protein and lipid oxidation, which was also reflected in Warner-Bratzler shear force VAC and DRY-AGED had positive results regarding tenderness, whereas on day 21 the MAP-stored meat had toughened significantly (from 35.3 N to 50.7 N in LTL). Lipids were oxidised much faster than proteins during prolonged storage in MAP. Compared to the other methods, DRY-AGED had the best effect on microbial growth.

CONCLUSION

These results indicate that the recommended methods for the storage of wild boar meat are either vacuum packing or dry ageing. The high oxygen content of MAP negatively affected the quality of wild boar meat and carried a risk of increased protein carbonylation. © 2022 Society of Chemical Industry.

Changes in Physico-Chemical and Storage Properties of Dry-Aged Beef Loin Using Electric Field Refrigeration System

The aim of this study is to establish the dry aging period of beef loin in an electric field refrigeration system. Beef loins (Korea quality grade 2) were dry aged at 0, −1, and −2 °C temperature in an electric field refrigeration system (air velocity, 5 ± 2 m/s) and aging stopped as the value of TPC reached 7 log CFU/g. Samples were examined by aging yield, trimming yield, pH, color, water holding capacity (WHC), cooking yield, shear force, total plate count (TPC), 2-thiobarbituric acid reactive substances (TBARS), and volatile basic nitrogen (VBN). The results for aging yield, trimming yield, redness, yellowness, and chroma decreased with increasing the dry aging period. Contrariwise, those for pH, lightness, hue angle, WHC, and cooking yield increased with the dry aging period. In shear force, the lowest value occurred at four weeks at all temperatures. The results for TPC, TBARS, and VBN increased with aging period, and VBN at 6 weeks at 0 °C and 9 weeks at −1 °C exceed the standard value (20 mg/100 g), while dry aging temperature had an effect on physico-chemical and storage properties by lower temperatures showed slower progress. Therefore, dry aging on an electric field refrigerate system can be used until 4 weeks at 0 °C, 8 weeks at −1 °C, and 10 weeks at −2 °C. However, considering physico-chemical properties, 4 weeks at every temperature is suitable for manufacturing soft dry-aged beef loin.

Characterizing the Flavor Precursors and Liberation Mechanisms of Various Dry-Aging Methods in Cull Beef Loins Using Metabolomics and Microbiome Approaches

The objective of this study was to characterize and compare the dry-aging flavor precursors and their liberation mechanisms in beef aged with different methods. Thirteen paired loins were collected at 5 days postmortem, divided into four sections, and randomly assigned into four aging methods (wet-aging (WA), conventional dry-aging (DA), dry-aging in a water-permeable bag (DWA), and UV-light dry-aging (UDA)). All sections were aged for 28 days at 2 °C, 65% RH, and a 0.8 m/s airflow before trimming and sample collection for chemical, metabolomics, and microbiome analyses. Higher concentrations of free amino acids and reducing sugars were observed in all dry-aging samples (p < 0.05). Similarly, metabolomics revealed greater short-chain peptides in the dry-aged beef (p < 0.05). The DWA samples had an increase in polyunsaturated free fatty acids (C18:2trans, C18:3n3, C20:2, and C20:5; p < 0.05) along with higher volatile compound concentrations compared to other aging methods (aldehyde, nonanal, octanal, octanol, and carbon disulfide; p < 0.05). Microbiome profiling identified a clear separation in beta diversity between dry and wet aging methods. The Pseudomonas spp. are the most prominent bacterial species in dry-aged meat, potentially contributing to the greater accumulation of flavor precursor concentrations in addition to the dehydration process during the dry-aging. Minor microbial species involvement, such as Bacillus spp., could potentially liberate unique and potent flavor precursors.

Metabolites Analysis on Water-Holding Capacity in Beef Longissimus lumborum Muscle during Postmortem Aging

Currently, the metabolomic research on water-holding capacity (WHC) of beef during postmortem aging is still insufficient. In this paper, the kit method was adopted for energy metabolites testing, the ultra-high-performance liquid chromatography (UHPLC) system was used for sample separation, and the mass spectrometer was applied to collect the primary and secondary spectra of the samples. The results showed that lactic acid reached saturation at day 2 postmortem, while energy metabolites changed significantly within day 2 postmortem (p < 0.05). Based on these findings, it was suggested that the energy metabolism qualities of the beef had already achieved a largely stable state at around day 2 postmortem. Then, through metabolomic analysis, 25 compounds were differentially abundant at days 0, 0.5, 1, and 2 during postmortem aging. Within the period of day 0−2 postmortem, the purine metabolism in beef was relatively active until 0.5 d postmortem, while glycolysis metabolism remained active until day 2 postmortem. The functions of the identified metabolites contribute to a more detailed molecular view of the processes behind WHC and are a valuable resource for future investigations into the flavor of postmortem beef.