High-oxygen Modified Atmosphere Packaging Research Articles

UV-C-Activated Riboflavin Crosslinked Gelatin Film with Bioactive Nanoemulsion for Enhanced Preservation of Fresh Beef in Modified Atmosphere Packaging.

This study explores a new eco-friendly approach for developing bioactive gelatin films using UV-C irradiation-induced photo-crosslinking. Riboflavin, a food-grade photoinitiator, was selected at an optimal concentration of 1.25% (w/w) for crosslinking gelatin under UV-C exposure for 4 to 22 min. Physicochemical analyses revealed enhanced tensile strength, reduced water vapor permeability, and lower water solubility in films crosslinked for up to 13 min. FTIR analysis demonstrated significant molecular changes, confirming the formation of crosslinking connections in gelatin-riboflavin films. Antimicrobial nanoemulsion (NE) (0.5, 0.75, 1% v/v) was incorporated into crosslinked films and applied to fresh beef. The 1% NE film exhibited the strongest antimicrobial effect, extending shelf-life by 20 days. In vitro release study confirmed Fickian diffusion behavior in the 1% NE film. This study also investigated the synergy between 1% NE film and three different types of modified atmosphere packaging (MAP) on the microbiological and physicochemical properties of beef for 26 days. The best results were achieved with 1% NE film under MAP1 and MAP2, which preserved meat redness and prevented lipid oxidation, extending the shelf-life up to 26 days. Therefore, UV-C irradiation-induced crosslinked bioactive film combined with high-oxygen MAP offers a promising solution for prolonging the shelf-life of beef.

Comparative proteomic analyses to investigate premature browning in high‑oxygen modified atmosphere packaged beef patties

This study compared the proteomics of beef patties under high‑oxygen modified atmosphere packaging (HiOx-MAP) and vacuum packaging (VP) during heating. The color and oxidation stability of fresh patties, and myoglobin denaturation of cooked patties were also measured. The results suggested that HiOx-MAP patties contained more oxymyoglobin in fresh meat and had higher myoglobin denaturation during heating than VP patties, resulting in premature browning (PMB) during cooking. Proteomic analysis found that the overabundance of proteasome subunit beta type-2 (PSMB2) and peroxiredoxin-2 (PRDX2) in HiOx-55 °C, which can remove the damaged proteins and inhibit oxidation respectively, are of benefit to meat color stability during storage, however, this was still insufficient to inhibit the occurrence of PMB during cooking. The high abundance of lamin B1 (LMNB1) in VP-55 °C can maintain the stability of meat color. This research provides greater understanding, based on proteomic perspectives, of the molecular mechanism of PMB.

Comparison of Gas Treatments of High Oxygen, Carbon Monoxide, and Nitric Oxide on Ground Beef Color in Modified Atmosphere Packaging.

The objective of this study was to evaluate the viability and performance of nitric oxide modified-atmosphere packaging (MAP) as a novel alternative to high oxygen and carbon monoxide MAP for ground beef. Packages of ground beef under high oxygen (HI-OX), carbon monoxide (CO), and nitric oxide (NO) atmospheres were evaluated for descriptive and instrumental color every 12 h during a 120 h display period. Surface myoglobin percentages, internal cooked color, thiobarbituric acid reactive substances (TBARS), and residual nitrite and nitrate were also evaluated. There were gas × time interactions for descriptive color, discoloration, a* values, b* values, deoxymyoglobin percentages, and metmyoglobin percentages (p < 0.05). There were also gas-type main effects for cooked color and TBARS (p < 0.05). Carbon monoxide maintained the most redness and least discoloration throughout the display period, while HI-OX started with a bright red color but rapidly browned (p < 0.05). Nitric oxide started as dark red to tannish-red but transitioned to a dull red (p < 0.05). However, NO had increased redness and a* values for internal cooked color (p < 0.05). Although CO outperformed NO packages, NO exhibited a unique color cycle warranting further research to optimize its use.

58. Pre-conditioning pork loins in vacuum packaging does not overcome the negative impact of subsequent high oxygen modified atmosphere packaging on quality traits

58. Pre-conditioning pork loins in vacuum packaging does not overcome the negative impact of subsequent high oxygen modified atmosphere packaging on quality traits

The pro-oxidant action of high-oxygen MAP on beef patties can be counterbalanced by antioxidant compounds from common hawthorn and rose hips

The objective of this research was to evaluate the effectiveness of antioxidant-rich extracts from rose hip (Rosa canina L.; RC) and hawthorn (Crataegus monogyna Jacq.; CM) at minimizing the oxidative damage to proteins and lipids in beef patties subjected to a high‑oxygen (HiOx-MAP) and vacuum (Vacuum) packaging atmosphere. The extracts of RC and CM were characterized by quantifying bioactive compounds, namely, phenolic compounds, tocopherols and vitamin C. Both fruits had high concentrations of bioactive compounds, with RC having the highest total phenolic and vitamin C content. Yet, CM was the most efficient in protecting beef patties against protein carbonylation, reducing, as a result, the instrumental toughness in cooked beef patties. The use of CM and RC extracts in beef patties significantly improved consumer purchase intention in HiOx-MAP packaging systems. The use of CM and RC extracts or their combination in future research would be an effective antioxidant means to decrease the pro-oxidative effects caused by HiOx-MAP in red meat.

Potential inhibitory effect of carbon dioxide on the spoilage behaviors of Pseudomonas fragi in high-oxygen packaged beef during refrigerated storage.

Pseudomonas fragi is a dominant meat spoilage organism under high-oxygen modified atmosphere packaging (HiOx-MAP). This work investigated the effects of CO2 on P. fragi growth and the related spoilage phenomena of HiOx-MAP beef. Minced beef incubated with P. fragi T1, a strain owning the strongest spoilage potential among isolates, was stored under CO2-enriched HiOx-MAP (TMAP; 50% O2/40% CO2/10% N2) or non-CO2 HiOx-MAP (CMAP; 50% O2/50% N2) at 4°C for 14 days. Compared to CMAP, TMAP maintained sufficient O2 levels to endow beef with higher a*values and meat color stability due to lower P. fragi counts from day 1 (P<0.05). TMAP samples also showed lower (P<0.05) lipase activity and protease activity within 14-days and 6-days than CMAP samples respectively. TMAP delayed the significantly increased pH and total volatile basic nitrogen contents occurred in CMAP beef during storage. Despite TMAP markedly promoted the lipid oxidation associated with higher concentrations of hexanal and 2,3-octanedione than CMAP (P<0.05), TMAP beef retained an acceptable organoleptic odor due to a CO2-inhibition on the microbial-induced 2,3-butanedione and ethyl 2-butenoate formation. This study provided a comprehensive insight into the antibacterial mechanism of CO2 on P. fragi in HiOx-MAP beef.

Rinse and chill®, frozen storage and retail packaging influence the quality of lamb loins

This study evaluated effects of Rinse&Chill® vs. control, storage condition (fresh, frozen-thawed) and retail packaging (high oxygen modified atmosphere packaging, vacuum skin packaging) on quality of lamb loins. Thirty-two lambs were slaughtered, and carcasses were allocated to Rinse&Chill® or control (n = 16 for each). Loins were aged for seven-days (fresh), and then allocated to fresh or freezing-thawing (frozen-thawed). After storage completion loins were cut into steaks then packaged in high oxygen modified atmosphere packaging (HiOxMAP) or vacuum skin packaging (VSP) and into 8-days simulated retail display. Rinse&Chill® samples had lower heme protein content and lipid oxidation (p < 0.05 for both) compared to control samples. In frozen-thawed lamb samples, VSP resulted in lower lipid oxidation, higher red values (a*), and lower Warner-Bratzler shear force compared to those in HiOxMAP (p < 0.05 for all). This study showed that Rinse&Chill® reduced lipid oxidation in lamb loins, and VSP can be used to improve the quality of frozen-thawed lamb in retail.

PSIII-20 The Effect of Waiting Time at the Lairage of Slaughterhouse of Fattening Bulls After a Long Transport on Animal Behavior, Carcass Quality and Meat Quality

Abstract The aim of this study was to evaluate the effect of waiting time at the lairage before slaughter in crossbred bulls after a long transport (~14h). One-half of the bulls of each transport (n = 8 transports; n = 48 ± 4 bulls/transport) were distributed in two treatments: short waiting time (SWT; &amp;lt; 2h; n = 179) and long waiting time (LWT; from 7 to 8h; n = 165). Animal behavior was recorded during waiting time at the lairage. The pH in Longissimus dorsi (LD) between 30 and 36 h postmortem, was registered and a subset of 24 LD were selected for meat quality evaluation. Each loin was cut in 5 slices, one to determine instrumental color, and the others were disposed in high oxygen modified atmosphere packaging (MAP) to evaluate instrumental color, microbiology, and color stability between d 1 to 12. Data were analyzed using mixed models with repeated measures. Animals standing with LWT treatment decreased (P&amp;lt; 0.001) after the first hour at the lairage (71% to 32%, between 1h and 2h, respectively). After 3h, standing time and non-nutritive oral behaviors started to increase until sixth hour at the lairage (63%). Meat pH was lesser (P &amp;lt; 0.01) for SWT (5.6 ± 0.05) compared with LWT (5.7 ± 0.05). However, the percentage of carcass classified as DFD (pH &amp;gt; 5.7) did not differ between treatments. Meat redness (a*) and yellowness (*b) at 30-36 h were greater (P &amp;lt; 0.05) for SWT (16.3 ± 0.94 and 16.7 ± 1.53, respectively) compared with LWT (15.1 ± 0.94 and 15.6 ± 1.53, respectively). The increase of activity after 3 h at the lairage could be related to the long fasting hours caused by a long transport, however after a long transport waiting time at the lairage had minimal detrimental effects on meat quality.

Beyond the eco-design of case-ready beef packaging: The relationship between food waste and shelf-life as a key element in life cycle assessment

This study aims to compare the environmental impact of three food packaging systems (Overwrap: OW, High Oxygen Modified Atmosphere Packaging: MAP and Vacuum Skin: VS) currently used in beef meat market, including the potential waste effect that derives from shorter shelf-life in the inventory and assessment. The Life cycle Assessment method was used, and a “cradle-to-grave” approach was applied for both packaging and meat chains. The functional unit was defined as one unit of packaging containing 500 g of sliced beef. Considering only the packaging life cycle, the OW system has the best environmental performance in most of the environmental impact categories, while considering the potential food waste effects, results showed that the packaging system with the longest shelf-life (VS) represents the best environmental solution. Future eco-design approaches for packaging solutions for food products should consider the ability of reducing potential food waste, as a direct consequence of improved shelf-life.

Impact of Modified Atmospheres on Growth and Metabolism of Meat-Spoilage Relevant Photobacterium spp. as Predicted by Comparative Proteomics.

Modified atmosphere packaging (MAP) is a common strategy to selectively prevent the growth of certain species of meat spoiling bacteria. This study aimed to determine the impact of high oxygen MAP (70% O2, 30% CO2, red and white meats) and oxygen-free MAP (70% N2, 30% CO2, also white meat and seafood) on preventing the growth of spoiling photobacteria on meat. Growth of Photobacterium carnosum and P. phosphoreum was monitored in a meat simulation media under different gas mixtures of nitrogen, oxygen, and carbon dioxide, and samples were taken during exponential growth for a comparative proteomic analysis. Growth under air atmosphere appears optimal, particularly for P. carnosum. Enhanced protein accumulation affected energy metabolism, respiration, oxygen consuming reactions, and lipid usage. However, all the other atmospheres show some degree of growth reduction. An increase in oxygen concentration leads to an increase in enzymes counteracting oxidative stress for both species and enhancement of heme utilization and iron-sulfur cluster assembly proteins for P. phosphoreum. Absence of oxygen appears to switch the metabolism toward fermentative pathways where either ribose (P. phosphoreum) or glycogen (P. carnosum) appear to be the preferred substrates. Additionally, it promotes the use of alternative electron donors/acceptors, mainly formate and nitrate/nitrite. Stress response is manifested as an enhanced accumulation of enzymes that is able to produce ammonia (e.g., carbonic anhydrase, hydroxylamine reductase) and regulate osmotic stress. Our results suggest that photobacteria do not sense the environmental levels of carbon dioxide, but rather adapt to their own anaerobic metabolism. The regulation in presence of carbon dioxide is limited and strain-specific under anaerobic conditions. However, when oxygen at air-like concentration (21%) is present together with carbon dioxide (30%), the oxidative stress appears enhanced compared to air conditions (very low carbon dioxide), as explained if both gases have a synergistic effect. This is further supported by the increase in oxygen concentration in the presence of carbon dioxide. The atmosphere is able to fully inhibit P. carnosum, heavily reduce P. phosphoreum growth in vitro, and trigger diversification of energy production with higher energetic cost, highlighting the importance of concomitant bacteria for their growth on raw meat under said atmosphere.

Investigation of the relationship between microbiota dynamics and volatile changes in chilled beef steaks held under high-oxygen packaging enriched in carbon dioxide

Carbon dioxide (CO2) plays an important bacteriostatic role in high-oxygen modified atmosphere packaging (HiOx-MAP). This study aimed to explore the influence of CO2 on the volatile organic compounds (VOCs) profile in HiOx-MAP beef steaks and assess the changes in VOCs associated with microbiota dynamics during 20-days of chilled storage. Compared to control MAP (CMAP: 50% O2/50% N2), CO2-enriched MAP (TMAP: 50% O2/40% CO2/10% N2) rendered steaks with desirable appearance and odor freshness during storage through inhibiting bacterial growth and reducing the accumulation of acetoin, 2-ethyl-1-hexanol, 1,3-butanediol, diacetyl and 2-heptanone (P < 0.05). 1-Octen-3-ol and 2-ethyl-1-hexanol were main VOCs in TMAP steaks and were positively related to Brochothrix thermosphacta levels. Acetoin and 2-ethyl-1-hexanol could be used as potential spoilage indicators in CMAP steaks, which were positively related to B. thermosphacta and Pseudomonas levels. Overall, the desirable odor freshness of TMAP steaks was mainly attributed to the CO2-inhibitory effect on the off-odor VOCs production correlated with B. thermosphacta, Pseudomonas and Serratia growth.

Combined effects of plant food processing by-products and high oxygen modified atmosphere packaging on the storage stability of beef patties

Plant food processing by-products (PFPB) have attracted industrial attention as a potential source of natural antioxidants that can be used in meat industry. This study investigated the combined effects of PFPB including sugarcane bagasse (SCF), orange peel (ORP) and tomato pomace (TMT), and high oxygen modified atmosphere packaging (HOMAP; 80 % O2: 20 % CO2) on the oxidative and microbial stability of beef patties during cold storage for up to 12 days. The total phenolic content (TPC) and antioxidant activity of the PFPB were also evaluated. ORP was found to have the highest TPC, followed by TMT and SCF. DPPH-radical and ABTS-radical assays demonstrated a similar trend. The PFPB were proved to successfully improve the meat properties of a* value and total viable count (TVC) and minimize lipid and protein oxidation, although the effectiveness did not exceed that of butylated hydroxytoluene (BHT). The HOMAP maintained the redness of beef patties and inhibited microbial growth compared to aerobic packaging, but did not improve lipid and protein oxidative stability. Overall, the combination of HOMAP and natural antioxidants from sugarcane, tomato and orange by-products can potentially improve the shelf life of beef patties by reducing oxidative deterioration of color, lipid and protein and delaying the growth of microorganisms. This research provided a reference for the future utilization of PFPB in meat preservation.

The texture and mastication properties of sheep biceps femoris from different finishing feeds and retail packaging methods.

This study investigated the relationship among meat texture (Warner-Bratzler shear force [WBSF] and texture profile analysis [TPA]), water-holding capacity, and subsequent mastication of meat from sheep fed different diets and maintained under different packaging methods. Biceps femoris from 24 Merino sheep fed a standard pelleted diet containing grain and cereal hay or pelleted diets supplemented with either 8% camelina meal or 15% camelina forage hay was packaged in high-oxygen modified atmosphere packaging (hiOxMAP) or vacuum skin packaging (VSP). WBSF, TPA, and water-holding capacity (purge loss and cooking loss) were measured. Twelve volunteers were recruited to chew the cooked meat samples before expectorating the bolus at their natural swallowing point. Meat stored in hiOxMAP had greater purge loss, Warner-Bratzler peak force, hardness, and chewiness compared to meat packed in VSP. Mastication testing revealed that chewing frequency increased with VSP meat compared to hiOxMAP meat. Feed type had little effect on meat texture parameters; however, sheep meat on the standard pelleted diet required a greater number of chews than sheep finished on diet supplemented with camelina meal. Increased toughness in cooked meat due to feed type or packaging methods resulted in greater chewing effort, but this did not affect meat bolus properties at the natural swallowing point.

Lipid and protein oxidation and colour stability during display in high oxygen modified atmosphere packaging of beef from late-maturing bulls fed rumen protected fish oil

Increasing the concentration of polyunsaturated fatty acids (PUFA) in beef enhances its nutritional value but may compromise its oxidative shelf life. In this experiment, the impact of inclusion of rumen protected fish oil (PFO) in the finishing diet of late-maturing bulls on muscle fatty acid profile, antioxidant content, lipid stability, colour and protein oxidation was investigated. Charolais-sired suckler bulls were offered ad libitum, for 101 d pre-slaughter, a barley-based concentrate (C) or a concentrate containing rumen PFO. Following post-mortem ageing for 14 d, M. Longissimus thoracis muscle was subjected to simulated retail display (4°C, 1,000 lux for 12 h out of 24 h) for 3, 7 and 10 d in modified atmosphere packs (O2:CO2; 80:20). The concentrations of C22:6n-3, n-6 PUFA and total PUFA and the n-6:n-3 PUFA ratio were higher (P &lt; 0.001) in muscle of PFO bulls compared to C bulls, while the α-tocopherol concentration was lower (P &lt; 0.01). The concentrations of C18:3n-6, C20:4n-6, n-3 PUFA and highly peroxidisable PUFA were lower (P &lt; 0.05) on day 14 compared to day 0 of display. Lipid oxidation after 10 d of display was higher (P &lt; 0.05) in muscle of PFO bulls compared to C bulls but not to an extent that would be detected by a consumer. Colour stability was not affected. It is concluded that the increase in PUFA concentration achieved had minor effects on bull beef shelf life.

The response of bacterial communities to carbon dioxide in high-oxygen modified atmosphere packaged beef steaks during chilled storage

The objective of this study was to establish the effect of CO2 on the bacterial community in beef steaks held under both high-oxygen modified atmosphere packaging (HiOx-MAP) types (CO2 treated MAP: 50% O2/40% CO2/10% N2; control MAP: 50% O2/50% N2). Steaks were stored at 2 °C for 20 days. Gas composition, meat color, pH values, total volatile basic nitrogen values, total viable counts (TVC) and microbial community dynamics were monitored. Compared to the control MAP, the high level of CO2 in the contrast MAP significantly delayed bacterial growth, resulting in a bright red color as well as extending the shelf-life to over 20 days. The microbial diversity decreased with prolonged storage in both MAP types, but it was more complex in high-CO2 treated MAP steaks. When TVC values approached the shelf-life threshold for the control MAP, Pseudomonas and Brochothrix were the predominant bacteria, while Pseudomonas and Serratia under the CO2 containing MAP were at a lower abundance than under the control MAP. The dominant Pseudomonas species causing spoilage in the control MAP steaks was P. fragi, and this species was inhibited significantly by CO2, followed by P. weihenstephanensis. Inversely, P. versuta instead of P. fragi became the dominant Pseudomonas species under the CO2 treated MAP. Overall, the application of CO2 in HiOx-MAP influenced microbiota succession, which played an important role in retaining beef quality.

Bacterial and Sensory Evaluation of Meat Preservation Using High-Oxygen Modified Atmosphere Packaging

Bacterial and Sensory Evaluation of Meat Preservation Using High-Oxygen Modified Atmosphere Packaging

Microbial Profile Evaluation of Beef Steaks From Different Packaging and Retail Lighting Display Conditions

To date, meat microbiology research has relied on culture-dependent methods. Amplicon sequencing technology provides a deeper look into the microbial community. This study set out to evaluate the bacterial community of fresh beef longissimus lumborum steaks exposed to retail packaging and display conditions. Four packaging treatments were assigned after fabrication 7 d postmortem: high-oxygen modified atmosphere packaging, overwrapped packages within a carbon monoxide tri-gas flushed motherbag, vacuum rollstock pouches, and traditional overwrap. After a 14-d dark storage, carbon monoxide motherbag overwrapped packages were removed from the motherbag, and packages were distributed to a retail lighting condition for 72 h of retail display: fluorescent, light emitting diode, or darkness. Aerobic plate count and psychrotrophic bacteria were enumerated, in addition to 16S ribosomal RNA sequencing of DNA for microbial profile investigation. Sampling occurred at fabrication (7 d), end of dark storage (20 d), and end of retail display (23 d). The V3–V4 regions of the 16S bacterial ribosomal RNA gene were sequenced using the Illumina MiSeq platform (Illumina, San Diego, CA). Counts for aerobic plate count bacteria differed by packaging (P = 0.039) but not lighting (P &amp;gt; 0.05). Firmicutes and Proteobacteria were the dominate phyla identified but were not affected by packaging or lighting (P &amp;gt; 0.05). Traditional overwrapped packages displayed in darkness and fluorescence had a higher abundance of Carnobacterium compared with those displayed under light emitting diode (P = 0.05). Dark-stored samples had more Pseudomonas compared with fluorescent display, regardless of packaging type (P = 0.03). While packaging and lighting conditions had a minimal impact on the community composition, these data positively contribute to a baseline establishing bacterial community profiles of fresh beef steaks subjected to retail display. This foundation suggests that further work is needed to understand whether shifts are more likely to occur during extended shelf life or in other retail beef display conditions.

Synergistic effects of ultraviolet light irradiation and high-oxygen modified atmosphere packaging on physiological quality, microbial growth and lignification metabolism of fresh-cut carrots

Abstract The present study investigated influences of ultraviolet light C (UV-C; 2 kJ m−2) irradiation and high-oxygen modified atmosphere packaging (MAP; 80 % O2, 10 % CO2 and 10 % N2) on physiological quality, microbial growth and lignification metabolism of fresh-cut carrots. After 15-d cold storage, comparing with either treatment alone, the combination of UV-C irradiation and high-oxygen MAP (abbr. UV-C + MAP) more obviously inhibited firmness, weight loss, ascorbic acid, total carotenoid and γ-aminobutyric acid declines, reduced respiration and ethylene production rates as well as delayed bacterial growth. UV-C + MAP more strongly restrained whiteness index, total phenolic, lignin and malondialdehyde increases. Furthermore, UV-C + MAP treatment more efficiently retarded lignin synthesis by suppressing phenolic metabolism-related enzyme (phenylalanine ammonialyase, PAL; polyphenoloxidase, PPO; peroxidase, POD) activities and their gene (DcPAL; DcPPO; DcPOD) expressions. Above results indicated that UV-C + MAP exhibited synergistic effects in retaining physiological quality, delayed senescence process, reducing microbial growth, alleviating lignification degree, and lessened surface whitening. Therefore, UV-C + MAP could maintain overall quality and extend shelf-life during storage of fresh-cut carrots.

Effectiveness of Sprayed Bioactive Fruit Extracts in Counteracting Protein Oxidation in Lamb Cutlets Subjected to a High-Oxygen MAP.

High-oxygen packaging atmosphere (High-Ox-MAP) promotes meat protein oxidation and leads to texture deterioration. This study was conceived to assess the extent to which sprayed fruit extracts could inhibit the oxidative damage to proteins in lamb cutlets subjected to High-Ox-MAP (10 days/4 °C) and subsequent roasting (10 min/180 °C). Extracts from oaknut (Quercus ilex subsp. ballota; QI), rose hips (Rosa canina L.; RC), common hawthorn (Crataegus monogyna Jacq.; CM) and strawberry tree (Arbutus unedo L.; AU) were characterized for bioactive compounds (phenolic subclasses, tocopherols and ascorbic acid) and in vitro bioactivities. While the four fruits showed relevant antioxidant potential, CM had the highest phenolics and tocopherol content and that was reflected in efficient antiradical activity. The in vitro activity of this fruit to inhibit meat protein oxidation was, however, lower than that displayed by the other fruits. Taking the results altogether, CM was also found to be most efficient in protecting lamb cutlets from lipid oxidation. All fruits were able to inhibit thiols oxidation except RC, which seemed to reduce protein thiols. Among fruits, QI was the most efficient in protecting lamb cutlets against protein carbonylation as a plausible involvement of ellagitannins. The inhibition of protein oxidation by QI was reflected in significantly lower instrumental hardness in cooked lamb cutlets. Spraying lamb cutlets with extracts from QI, RC and CM improved consumers’ purchase intention after chilled storage. This antioxidant strategy seems to be a feasible and efficient solution to the pro-oxidative effects caused by High-Ox-MAP in red meat.

Determination of Package and Muscle-Type Influence on Proteolysis, Beef-Flavor-Contributing Free Amino Acids, Final Beef Flavor, and Tenderness

The objectives of this study were to determine the influence of package and muscle type on postmortem proteolysis and subsequent release of flavor-contributing free amino acids during storage. Beef strip loins and top sirloin butts (n = 20/subprimal) from USDA Low Choice carcasses were fabricated into 2.54-cm steaks (M. longissimus lumborum and M. gluteus medius) at 7 d postmortem. Steaks were randomly assigned to packaging treatments (carbon monoxide mother-bag [CO], high-oxygen modified atmosphere packaging [HIOX], polyvinyl overwrap [OW], or rollstock [ROLL]) and aged for an additional 14 d in dark storage. Steaks intended for OW were initially vacuum packaged during dark storage,then overwrapped just prior to display. Steaks were placed in coffin-style retail cases for 48 h under fluorescent lighting to simulate retail display. HIOX steaks exhibited the highest Warner-Bratzler shear force values (P < 0.05); the lowest desmin degradation rate (P < 0.05); the highest ratings for fishy, bitter, sour, and oxidized flavors; and the lowest overall tenderness scores (P < 0.05) and, in general, produced the lowest amount of free amino acids (P < 0.05) compared with all other treatments. Contrastingly, ROLL packaging produced the highest ratings for beef flavor identity, brown/roasted, bloody/serumy, and umami flavors (P < 0.05). Additionally, ROLL packaging exhibited (P < 0.05) greater desmin degradation in comparison with HIOX steaks. These data indicate that the optimum package for storage and aging is an anaerobic environment to maintain optimum flavor, tenderness, and postmortem proteolysis.