Colour, lipid and protein stability of Rhea americana meat during air- and vacuum-packaged storage: Influence of muscle on oxidative processes

Effect of Feeding Alfalfa and Concentrate on Meat Quality and Bioactive Compounds in Korean Native Black Goat Loin during Storage at 4°C

The primary aim of this study was to evaluate the effect of feeding alfalfa: Concentrate at different ratios (8:2 or 2:8) to Korean native black goats (KNBG) for 90 days on meat quality and bioactive compound content. Feeding KNBG alfalfa and concentrate at different ratios did not impact meat pH, color, microorganism composition, volatile basic nitrogen levels, or lipid oxidation. The low alfalfa (KLA) group exhibited increased oleic acid and monosaturated fatty acid levels, both of which impact the palatability traits of meat. The abundance of bioactive compounds increased in the loin meat of the KLA group, leading to an increase in antioxidant activities. Our results suggest that feeding alfalfa and concentrate at a 2:8 ratio to KNBG can increase taste-related fatty acids and bioactive compounds in loin meat, relative to that achieved by feeding at an 8:2 ratio. Further investigation is required to evaluate the quality and the metabolites of bioactive compounds in KNBG meat and the effect of the different dietary ratios of forage and concentrate.

Effect of Packaging Type and Aging on the Meat Quality Characteristics of Water Buffalo Bulls

Simple Summary

The water buffalo is found worldwide, but mainly in Asian countries, i.e., India, Pakistan, and China. Buffalo meat can be a viable option to fulfill the future protein demands of the world’s population. Presently, very little information is available regarding buffalo meat quality attributes under different packaging types. Therefore, this study was designed to evaluate the effect of packaging type and aging time on the meat quality characteristics (instrumental color, WBSF, cooking loss, thiobarbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVB-N) of longissimus lumborum steaks. The results showed that vacuum packaging and aging were the most effective in decreasing the WBSF values of buffalo meat.

Abstract

The present study determined the effect of the packaging type and aging time on the meat quality of water buffalo (Bubalus bubalis) bulls. A total of n = 36 longissimus lumborum (LL) muscles from n = 18 buffalo bulls were obtained. Half LL muscles were packed in modified atmosphere packaging (Hi-O₂ MAP), vacuum packaging (VP), and oxygen-permeable packaging (OP) on day 1, while the other half were aged for 7 days. Meat instrumental color, cooking loss, Warner–Bratzler shear force (WBSF), thiobarbituric acid reactive substances (TBARS), and total volatile basic nitrogen (TVB-N) of the LL steaks were analyzed, both on unaged and aged buffalo meat. Color CIE L* and C* values on all display days and a* on the first 4 days of the simulated retail display under Hi-O₂ MAP packaging were significantly higher than those of the VP and OP. WBSF and TBARS values were also higher under Hi-O₂ MAP as compared to the other packaging. Steaks under OP exhibited lower cooking loss but higher TVB-N values than the MAP and VP. The 7-day-aged buffalo meat indicated higher instrumental color (L*, a* and C*), cooking loss, and lower WBSF values than fresh meat. This study concluded that Hi-O₂ MAP improved the color; however, it negatively influenced the buffalo meat’s WBSF and TBAR values. Furthermore, VP and aging were the most effective in decreasing the WBSF values of buffalo meat.

Protein Oxidation in Muscle Foods: A Comprehensive Review

Muscle foods and their products are a fundamental part of the human diet. The high protein content found in muscle foods, as well as the high content of essential amino acids, provides an appropriate composition to complete the nutritional requirements of humans. However, due to their special composition, they are susceptible to oxidative degradation. In this sense, proteins are highly susceptible to oxidative reactions. However, in contrast to lipid oxidation, which has been studied in depth for decades, protein oxidation of muscle foods has been investigated much less. Moreover, these reactions have an important influence on the quality of muscle foods, from physico-chemical, techno-functional, and nutritional perspectives. In this regard, the loss of essential nutrients, the impairment of texture, water-holding capacity, color and flavor, and the formation of toxic substances are some of the direct consequences of protein oxidation. The loss of quality for muscle foods results in consumer rejection and substantial levels of economic losses, and thus the control of oxidative processes is of vital importance for the food industry. Nonetheless, the complexity of the reactions involved in protein oxidation and the many different factors that influence these reactions make the mechanisms of protein oxidation difficult to fully understand. Therefore, the present manuscript reviews the fundamental mechanisms of protein oxidation, the most important oxidative reactions, the main factors that influence protein oxidation, and the currently available analytical methods to quantify compounds derived from protein oxidation reactions. Finally, the main effects of protein oxidation on the quality of muscle foods, both from physico-chemical and nutritional points of view, are also discussed.

The Activity of Chosen Antioxidant Enzymes in Ostrich Meat in Relation to the Type of Packaging and Storage Time in Refrigeration

The aim of the study was to investigate the changes in the activity of antioxidant enzymes, i.e., superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity in ostrich meat, as influenced by various packaging systems and storage time under refrigeration. Three packaging methods were used: vacuum packaging (VP) and modified atmosphere packaging (MAP) in two combinations of gases, MAP1 (40% O₂/40% CO₂/20% N₂) and MAP2 (60% O₂/30% CO₂/10% N₂). Meat samples were taken from the M. ilifibularis (IF) muscles of eight ostriches in each treatment group. The meat samples were stored in a refrigerator in 2 °C and analyzed at days 0, 4, 8, 12 and 16. The lowest level of SOD activity during storage was observed in ostrich muscles packed in vacuum, as compared to MAP1 and MAP2. In turn, the highest increase in GPx activity was recorded in VP, especially up to day 8 of storage, when this parameter reached maximum value (54.37). GR increased up to the eighth day of storage in MAP1 and VP. Between the 12th and 16th days of storage, stabilization of the GR activity level was observed only in VP, while under MAP1, it further decreased. DPPH remained relatively stable until the eighth day of storage and after this period, a decrease in this parameter was recorded, reaching the lowest value on day 12 for all types of packaging systems.

Thermal processing implications on the digestibility of meat, fish and seafood proteins

Thermal processing is an inevitable part of the processing and preparation of meat and meat products for human consumption. However, thermal processing techniques, both commercial and domestic, induce modifications in muscle proteins which can have implications for their digestibility. The nutritive value of muscle proteins is closely related to their digestibility in the gastrointestinal tract and is determined by the end products that it presents in the assimilable form (amino acids and small peptides) for the absorption. The present review examines how different thermal processing techniques, such as sous-vide, microwave, stewing, roasting, boiling, frying, grilling, and steam cooking, affect the digestibility of muscle proteins in the gastrointestinal tract. By altering the functional and structural properties of muscle proteins, thermal processing has the potential to influence the digestibility negatively or positively, depending on the processing conditions. Thermal processes such as sous-vide can induce favourable changes, such as partial unfolding or exposure of cleavage sites, in muscle proteins and improve their digestibility whereas processes such as stewing and roasting can induce unfavourable changes, such as protein aggregation, severe oxidation, cross linking or increased disulfide (S-S) content and decrease the susceptibility of proteins during gastrointestinal digestion. The review examines how the underlying mechanisms of different processing conditions can be translated into higher or lower protein digestibility in detail. This review expands the current understanding of muscle protein digestion and generates knowledge that will be indispensable for optimizing the digestibility of thermally processed muscle foods for maximum nutritional benefits and optimal meal planning.

Selected freshness indices of skin and wings from organic chicken packaged in modified atmosphere

This study is part of a project aiming to optimize storage conditions for organic chicken meat. Selected indices of skin and wings from organic chicken were evaluated. A total of 24 samples were packaged in MAP-O2 (80% O2/20% CO2), 24 samples in MAP-N2 (70% N2/30% CO2) and 48 samples as a control. The samples were analysed on days 2, 7, 10 and 14 of storage during a 14-day storage period at 2 ± 2 °C. The surface colour of skin (L*a*b*), ammonia content, thiobarbituric acid reactive substances content (TBARS) and antioxidant capacity were assessed. The lightness values (L*) for chicken skin in MAP-O2 were increased on days 7 and 10 of the storage period, and were significantly (P < 0.05) higher than in the samples in MAP-N2 and the control. Significant increases of TBARS were observed in the samples in MAP-O2 from day 7 and these values continued to increase until the end of the storage period. The antioxidant capacities of the samples in MAP-O2 were mostly lower than those of the samples in MAP-N2. Our results indicate that MAP-O2 only had a positive effect on skin colour, whereas MAP-N2 maybe preferable for shelf-life prolongation.

Effects of packaging conditions on some functional and sensory attributes of goose meat

The objective of the work was to investigate the effect of modified atmosphere (MA) packaging (high oxygen modified atmosphere and vacuum) on pH, water holding capacity and cooking loss of raw goose meat, and on the sensory assessment and shear force of roasted meat. Samples refrigerated at 1°C were tested within 24 h after slaughter (unpacked meat) and on d 4, 7, 11, and 14 of storage (modified atmosphere or vacuum packed meat).The type of atmosphere used in packaging determined the functional properties of goose meat such as: pH, WHC, cooking loss and shear force. This is important from both the culinary and technological viewpoint. At the end of storage the meat packed in MA (consisting of 80% O2, 20%CO2) had higher cooking loss, lower pH values, and water holding capacity in comparison to samples stored in vacuum. The type of atmosphere influenced the sensory descriptors (characteristic odor and flavor, tenderness, juiciness and general evaluation) of roasted meat. Samples packed in MA did worse during sensory assessment with respect to odor and flavor, tenderness, juiciness and general assessment. Thus meat stored under modified atmosphere showed lower productivity and was less tender and juicy.The goose breast muscles packed in vacuum proved to be better suited for consumption and processing as compared to those packed in high oxygen MA.

Change of the structure and the digestibility of myofibrillar proteins in Nanjing dry-cured duck during processing

BACKGROUND

To investigate the change of bioavailability and structure of myofibrillar proteins during Nanjing dry-cured duck processing, carbonyl content, sulfhydryl (SH) group, disulfide (SS) group, sodium dodecyl sulfate polyacrylamide gel electrophoresis, surface hydrophobicity, secondary structures and in vitro digestibility were determined.

RESULTS

During processing, carbonyl content and surface hydrophobicity increased; SH turned into SS group; α-helix turned into β-sheet and random coil fractions. Protein degradation occurred during dry-curing and drying-ripening stages. The in vitro digestibility of pepsin and pancreatic proteases increased during the salt curing stage and decreased during the drying-ripening stage.

CONCLUSION

The increase of digestibility could be attributed to the mild oxidation, degradation and unfolding of proteins while the decrease of digestibility was related to the intensive oxidation and aggregation of proteins. Protein degradation was not a main factor of digestibility during the drying-ripening stage. Results demonstrated that the bioavailability loss of myofibrillar proteins in Nanjing dry-cured duck occurred during the stage of drying-ripening instead of curing. © 2017 Society of Chemical Industry.

Meat quality traits in the Greater rhea (Rhea americana) as influenced by muscle, sex and age

Meat from the Greater rhea (Rhea americana) could compete with traditional red meats, diversifying the market of protein products of animal origin. The meat from 32 rheas was used to study quality aspects and this included ultimate pH (pHu), color, water-holding capacity (WHC%), cooking loss (CL%) and tenderness. The muscles sampled were the Gastrocnemius pars externa, Iliofibularis and Obturatorius medialis from both sexes at multiple ages (10, 12, 14, 16 months). Age at slaughter affected WHC%, CL%, and color in raw meat and tenderness in cooked meat. Muscles under study showed differences in terms of pHu, raw meat color, and tenderness of cooked meat. Sex did not have a significant effect on any of the variables studied. According to our results, rhea meat from younger animals, between 10 to 14 months old, was tender and moderately juicy and the visual color was appreciated by the consumers.

Optimization of low-fat meat hamburger formulation containing quince seed gum using response surface methodology

In the present study, feasibility of low-fat hamburger production by partial replacement with quince seed gum (QSG) was investigated. The effects of different QSG levels (1.2, 2.4, 3.6, and 4.8 wt%) on cooking loss, water holding capacity, lipid oxidation, antioxidant activity, and hardness of hamburger were investigated during a period of 9 days. The optimization was carried out based on minimum cooking loss, lipid oxidation, and maximum water holding capacity, antioxidant activity, and tissue hardness. Optimum conditions were achieved as 3.26% oil, 4.73% QSG, and 8.25th day of storagability. According to the optimum conditions, values for cooking loss, water holding capacity, lipid oxidation, free radical scavenging, raw hamburger hardness, and fried hamburger hardness were as 13.80%, 55.61%, 0.59 mg MDA/Kg, 48.12%, 2.99 N, and 8.66 N, respectively. Overall acceptability of optimized hamburgers was better and more acceptable than control ones.

Effects of Packaging Methods on Shelf Life of Ratite Meats

Over the last years a growing demand for ratite meat, including ostrich, emu, and rhea has been observed in the world. Ratite meat is recognised as a dietetic product because of low level of fat, high share of PUFA, favourable n6/n3 ratio, and higher amounts of iron content in comparison with beef and chicken meat. The abundance of bioactive compounds, e.g. PUFA, makes ratite meat highly susceptible to oxidation processes. Moreover, pH over 6 creates favourable environment for fast microbial growth during storage conditions affecting its shelf life. However, availability of information on ratite meat shelf life among consumers and industry is still limited. Thus, the aim of the present review is to provide current information about the effect of ratite meat packaging type, i.e. air packaging, vacuum packaging with skin pack, modified atmosphere packaging (MAP), on its shelf life quality during storage, including technological and nutritional properties.

Supplementing entire male pig diet with hydrolysable tannins: Effect on carcass traits, meat quality and oxidative stability

The purpose of the present study was to investigate the potential impact on carcass and meat quality of a sweet chestnut wood extract (SCWE)diet supplement for pigs, in particular on oxidative stability and fatty acid composition. Entire (non-castrated) male pigs (n=24) were assigned to treatment groups within litter and offered one of 4 finisher diets on an ad libitum basis: T0 (control), T1, T2 or T3, supplemented with 0, 1, 2 or 3% of commercially available SCWE, respectively. The highest SCWE supplementation reduced carcass fat deposition and water holding capacity of meat (higher thawing loss). In fresh meat, SCWE supplementation increased lipid (malondialdehyde) and protein oxidation (carbonyl groups in myofibril isolates). With regard to fat tissue, SCWE supplementation increased the proportion of polyunsaturated fatty acids.

Technological and nutritional properties of ostrich, emu, and rhea meat quality

In recent years a growing demand for ratite meat, including ostrich, emu, and rhea has been observed all over the world. However, consumers as well as the meat industry still have limited and scattered knowledge about this type of meat, especially in the case of emu and rhea. Thus, the aim of the present review is to provide information on technological and nutritional properties of ostrich, emu, and rhea meat, including carcass composition and yields, physicochemical characteristics, and nutritive value. Carcass yields and composition among ratites are comparable, with the exception of higher content of fat in emu. Ostrich, emu, and rhea meat is darker than beef and ratite meat acidification is closer to beef than to poultry. Ratite meat can be recognised as a dietetic product mainly because of its low level of fat, high content of polyunsaturated fatty acids (PUFA), favourable n6/n3 ratio, and high iron content in comparison with beef and chicken meat. Ratite meat is also rich in selenium, copper, vitamin B, and biologically active peptides such as creatine (emu) and anserine (ostrich), and has low content of sodium (ostrich). The abundance of bioactive compounds e.g. PUFA, makes ratite meat highly susceptible to oxidation and requires research concerning elaboration of innovative, intelligent packaging system for protection of nutritional and technological properties of this meat.

Impact of divergent selection for ultimate pH of pectoralis major muscle on biochemical, histological, and sensorial attributes of broiler meat

The impact of divergent selection based on the ultimate pH (pHu) of pectoralis major (P. major) muscle on the chemical, biochemical, and histological profiles of the muscle and sensorial quality of meat was investigated in broiler chickens. The protein, lipid, DM, glycogen and lactate content, glycolytic potential, proteolysis, lipid and protein oxidation index, muscle fiber cross-sectional area, capillary density, and collagen surface were determined on the breast P. major muscle of 6-wk-old broilers issued from the high-pHu (pHu+) and low-pHu (pHu-) lines. Sensory attributes were also evaluated on the breast (roasted or grilled) and thigh (roasted) meat of the 2 lines. Protein, lipid, and DM content of P. major muscle were not affected by selection ( > 0.05). However, the P. major muscle of the pHu+ line was characterized by lower residual glycogen (-16%; ≤ 0.001) and lactate (-14%; ≤ 0.001) content and lower glycolytic potential (-14%; ≤ 0.001) compared with the pHu- line. Although the average cross-sectional area of muscle fibers and surface occupied by collagen were similar ( > 0.05) in both lines, fewer capillaries per fiber (-15%; ≤ 0.05) were observed in the pHu+ line. The pHu+ line was also characterized by lower lipid oxidation (thiobarbituric acid reactive substance index: -23%; ≤ 0.05) but protein oxidation and proteolysis index were not different ( > 0.05) between the 2 lines. At the sensory level, selection on breast muscle pHu mainly affected the texture of grilled and roast breast meat, which was judged significantly more tender ( ≤ 0.001) in the pHu+ line, and the acid taste, which was less pronounced in the roasted breast meat of the pHu+ line ( ≤ 0.002). This study highlighted that selection based on pHu does not affect the chemical composition and structure of breast meat. However, by modifying muscle blood supply and glycogen turnover, it affects meat acidity and oxidant status, both of which are likely to contribute to the large differences in texture observed between the 2 lines.

Changes of microbial spoilage, lipid-protein oxidation and physicochemical properties during post mortem refrigerated storage of goat meat

Examined was the effect of post mortem refrigerated storage on microbial spoilage, lipid-protein oxidation and physicochemical traits of goat meat. Seven Boer bucks were slaughtered, eviscerated and aged for 24 h. The Longissimus lumborum (LL) and Semitendinosus (ST) muscles were excised and subjected to 13 days post mortem refrigerated storage. The pH, lipid and protein oxidation, tenderness, color and drip loss were determined in LL while microbiological analysis was performed on ST. Bacterial counts generally increased with increasing aging time and the limit for fresh meat was reached at day 14 post mortem. Significant differences were observed in malondialdehyde (MDA) content at day 7 of storage. The thiol concentration significantly reduced as aging time increased. The band intensities of myosin heavy chain (MHC) and troponin-T significantly decreased as storage progressed, while actin remained relatively stable. After 14 days of aging, tenderness showed significant improvement while muscle pH and drip loss reduced with increase in storage time. Samples aged for 14 days had higher lightness (P < 0.05) and lower (P < 0.05) yellowness and redness. Post mortem refrigerated storage influenced oxidative and microbial stability and physico-chemical properties of goat meat.

Development of microbial spoilage and lipid and protein oxidation in rabbit meat

This experiment aimed to determine microbial spoilage and lipid and protein oxidation during aerobic refrigerated (4°C) storage of rabbit meat. Forty male New Zealand white rabbits were slaughtered according to the Halal slaughter procedure. The hind limbs were used for microbial analysis while the Longissimus lumborum m. was used for determination of lipid and protein oxidation. Bacterial counts generally increased with aging time and the limit for fresh meat (10(8)cfu/g) was reached at d 7 postmortem. Significant differences in malondialdehyde content were observed after 3d of storage. The thiol concentration significantly decreased with increase in aging time. The band intensities of myosin heavy chain and troponin T significantly reduced with increased refrigerated storage while actin remained relatively stable. This study thus proposes protein oxidation as a potential deteriorative change in refrigerated rabbit meat along with microbial spoilage and lipid oxidation.

Color stability and antioxidant capacity of yak meat as affected by feeding with pasture or grain

Chen, C., Han, L., Yu, Q.-L. and Li, R.-R. 2015. Color stability and antioxidant capacity of yak meat as affected by feeding with pasture or grain. Can. J. Anim. Sci. 95: 189–195. The objective of the present study was to analyze the effect of pasture or grain on color stability and antioxidant capacity of M. longissimus lumborum (LL) from pasture-fed (PF) or grain-fed (GF) yaks. The color stability and metmyoglobin percentage (MetMb%) were determined during 9 d of aerobic refrigerated storage. The antioxidant capacity was estimated by the total phenolics content, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP). Compared with the GF group, the LL from the PF group showed significantly (P<0.05) higher redness (a* values), with lower decline rate in a* values (P<0.05) over 1 to 7 d of refrigerated storage. The LL from the PF group had a significantly (P<0.05) lower metmyoglobin accumulation rate. At the end of storage, the muscle's MetMb% of the PF and GF group were 46.33 and 56.66%, respectively. The PF group showed significantly higher total phenolics content (+23.94%; P<0.05) in muscles, resulting in greater TEAC and FRAP, which were 24.81 and 3.99% higher than the GF group (P<0.05), respectively. In conclusion, the pasture enhanced antioxidant capacity of yak meat and contributed to improve the meat color stability.

Oxidative damage to poultry: from farm to fork

Poultry and poultry meat are particularly susceptible to oxidative reactions. Oxidation processes have been for decades the focus of animal and meat scientists owing to the negative impact of these reactions on animal growth, performance, and food quality. Lipid oxidation has been recognized a major threat to the quality of processed poultry products. The recent discoveries on the occurrence of protein oxidation in muscle foods have increased the scientific and technological interest in a topic that broadens the horizons of food biochemistry into innovative fields. Furthermore, in recent years we have witnessed a growing interest in consumers on the impact of diet and oxidation on health and aging. Hence, the general description of oxidative reactions as harmful phenomena goes beyond the actual impact on animal production and food quality and reaches the potential influence of oxidized foods on consumer health. Likewise, the current antioxidant strategies aim for the protection of the living tissues, the food systems, and a potential health benefit in the consumer upon ingestion. Along these lines, the application of phytochemicals and other microelements (Se, Cu) with antioxidant potential in the feeds or directly in the meat product are strategies of substantial significance. The present paper reviews in a concise manner the most relevant and novel aspects of the mechanisms and consequences of oxidative reactions in poultry and poultry meat, and describes current antioxidant strategies against these undesirable reactions.

Impact of Dietary α -Lipoic Acid on Antioxidant Potential of Broiler Thigh Meat

The lipid oxidation depressed the meat quality and can be triggered during industrial processing. The current study was designed to assess the antioxidant activity of thigh meat and meat products enriched with natural antioxidants (α-lipoic acid andα-tocopherol acetate). Broilers (21 days) were fed on feed supplemented with varyingα-lipoic acid and constant concentration ofα-tocopherol acetate for 3 weeks. Birds were slaughtered at the age of 42 days and meat samples were collected and stored for further analysis and product preparation. TPC and DPPH value indicated that meat of broilers receiving 100 mg ofα-lipoic acid with 200 mg ofα-tocopherol acetate/kg of feed possessed the highest antioxidant activity. TBARS and peroxides values were found to be lower for meat of broilers fed on different levels ofα-lipoic acid. The antioxidants (lipoic acid and tocopherol) enrichment in meat helps to reduce PUFAs. A similar lipid stability trend was observed in nuggets prepared from broiler thigh meat and maximum sensory evaluation scores for nuggets prepared from thigh meat of broilers having the highest dose of lipoic acid. The lipoic acid supplementation in feed enhances the antioxidant capacity of thigh meat and meat products.

Effects of vacuum packaging conditions on the quality, biochemical changes and the durability of ostrich meat

In this study, the effects of vacuum packaging conditions on the concentrations of lactic acid, malondialdehyde, pH, microbial and sensory analysis were determined during chilled storage of ostrich meat. Meat was packed as follows: vacuum packed from 1st day (VP-1), vacuum packed from 3rd day (VP-3) and non-vacuum packed (NVP). Analysis were performed at 1st, 7th, 14th, 21st day after slaughter. Meat consisted of 74.69% water, 2.29% fats, 20.95% proteins. Package conditions had significant effect on the pH (NVP: 6.54 on the 14th day, VP-1: 6.05 and VP-3: 6.07 on the 21th day p<0.001), amount of malondialdehyde (NVP: 8.62mg/kg on the 14th day; VP-1: 1.95 and VP-3: 2.55 on the 21th day; p<0.001) and total microbial count (NVP: 7.4 log CFU/g on the 14th day; VP-1: 6.7 and VP-3: 6.8 on the 21th day p<0.01). Based on these results we can assess that vacuum packed from 1st day is necessary for the 21 days storage of ostrich meat.

Physicochemical and microbiological changes during the refrigerated storage of lamb loins sous-vide cooked at different combinations of time and temperature

This study aimed to determine the influence of cooking temperature (either 60 ℃ or 80 ℃) and time (6 h or 24 h) on the physicochemical (weight loss, moisture content, instrumental color, instrumental texture, lipid and protein oxidation) and microbiological changes underwent by sous-vide cooked lamb loins during refrigerated storage for 30 days. There was a slight trend to decreasing weight losses in some of the cooking treatments, but only in samples cooked at 60 ℃ for 6 h it was paralleled with an increase in moisture content. The only noteworthy oxidative change was a marked decrease in conjugated dienes after two weeks of storage in samples cooked at 80 ℃ for 24 h. Neither instrumental texture nor color showed noticeable variations during the storage. Microbial population remained quite low during the whole refrigerated storage. Overall, most of the studied parameters showed only scarce changes throughout 30 days of refrigerated storage that most likely would not influence the quality of sous-vide cooked loin lambs.

Carcass yields and meat quality characteristics of adult emus (Dromaius novaehollandiae) transported for 6h before slaughter

The meat quality characteristics of adult emus transported for 6h before slaughter were determined. Forty-two emus were used in two trials, undertaken under warm and cool weather conditions, respectively. Male emus had significantly higher fat yields than females (12.43kg vs 9.5kg, P=0.002). About 38.1% of the emus had no wounds or bruises, 40.5% had bruises, while 21.4% had small wounds after transport. Meat from injured emus had significantly higher pH45. In warm weather, emus experienced significantly higher loss in body weight than that under cool weather. Drip loss in meat after 24h of storage was higher in emus which had greater live weight loss after transport (r=0.66, P<0.0001), confirming the adverse effects of transport stress on meat quality. Nutrient supplementation did not significantly affect processing yield or meat quality characteristics. This study points to the need for optimizing transport conditions of emus to maintain meat quality.

Shelf life of cooked goat blood sausage prepared with the addition of heart and kidney

This study focused on the effect of two packaging formats (vacuum packaging and over-wrap packaging) on the shelf life of cooked sausage prepared with blood, heart, kidney and goat meat fragments under storage at 4±1°C for a period of 90 days. The storage time and type of packaging significantly affected the chemical (pH, moisture, protein and TBARS number), physical (shear force) and microbial (mould and yeast) parameters of cooked sausage. Vacuum packaging maintained the microbiological and chemical qualities of cooked goat blood sausage for a longer period of time (63 days) compared to over-wrap packaging (41 days) and could be a viable alternative to refrigerated storage of the product for quality maintenance.

Differentiation of Deboned Fresh Chicken Thigh Meat from the Frozen-Thawed One Processed with Different Deboning Conditions

This study was performed to evaluate the quality characteristics of three deboned categories of chicken thigh meat: one which was slaughtered and deboned in the same plant (fresh); one which was slaughtered, deboned, frozen, and thawed in the same plant (frozen-thawed); and the last which was slaughtered in a plant, deboned in a different plant, but then transferred to the original plant (fresh-outside). Surface color, drip loss, 2-thiobarbituric acid reactive substances (TBARS) value, sensory evaluation, and total aerobic bacterial counts of the chicken samples were determined. Moreover, the torrymeter was used to measure the differences in freshness of the chicken meat. The surface color and the TBARS values did not show significant differences among the three categories. However, the total aerobic bacterial counts of fresh-outside and frozen-thawed chicken meat were significantly higher than the fresh chicken meat on the first storage day, and the drip loss of frozen-thawed chicken meat was significantly higher than the fresh-outside and fresh chicken meat. In addition, the sensory evaluation of frozen-thawed chicken meat was significantly lower than the fresh-outside and fresh chicken meat. Torrymeter values were higher in fresh chicken meat than fresh-outside and frozen-thawed chicken meat during the storage period. These results indicate that the quality of frozen-thawed chicken meat is comparatively lower than the fresh chicken meat, and the torrymeter values can accurately differentiate the fresh-outside and frozen-thawed chicken meat from the fresh ones.

Muscle composition slightly affects in vitro digestion of aged and cooked meat: identification of associated proteomic markers

Meat is an appropriate source of proteins and minerals for human nutrition. Technological treatments modify the physical-chemical properties of proteins, making them liable to decrease the nutritional potential of meat. To counteract this damage, antioxidants and chaperone proteins in muscle cells can prevent oxidation, restore the function of denatured proteins, and thus prevent aggregation. This study aimed to explore the impact of indoor vs outdoor-reared meat protein composition on digestion and to associate protein markers to in vitro digestion parameters. Indoor-reared meat tended to show less oxidation and denaturation than outdoor-reared meat and was characterised by an overexpression of contractile and chaperone proteins. Outdoor-reared meat showed amplification of antioxidant and detoxification metabolism defending against oxidised compounds. Impacts on digestion remained minor. Several protein markers of in vitro digestion parameters were found for aged and cooked meat, linked to the detoxification process and to muscle contraction.

Relationship between histochemical, structural characteristics and oxidative stability of rhea limb muscles

Histochemical and structural characteristics were investigated in Gastrocnemius pars interna (GN) and Iliofiburalis (IF) limb muscles of Rhea americana. The average myofibre area cross-section was greater in GN than IF muscle (p<0.001), whereas the fibre density per section was higher in IF than GN muscle. The only type of myofibre found in both the rhea limb muscles analysed in this study was fast-twitch oxidative-glycolytic fibres (FOG). Immunolabelling analysis and ultrastructural observation of myofibres confirmed the contractile and metabolic characteristics of rhea myofibres, revealing the absolute fast isoform of myosin heavy chain and the abundance of glycogen and mitochondria inside the cells, mainly in IF muscle. These findings converged with previous results on the biochemical and physicochemical characteristics of rhea meat to provide further evidence that myofibre composition substantially influences the oxidative reactions of the muscle and therefore the meat quality, but more in-depth examination is needed to establish the links between myofibre characteristics, myofibre glycogen concentration and meat stability during storage.

Effect of frozen storage duration and cooking on physical and oxidative changes in M. Gastrocnemius pars interna and M. Iliofiburalis of Rhea americana

This study was conducted to evaluate the effect of frozen storage time (30, 60, 90 or 180 days) and cooking (100 °C, 30 min) on the physical characteristics and oxidative stability of M. Gastrocnemius pars interna (GN) and M. Iliofiburalis (IF) of rhea americana. Physical parameters measured included thawing and cooking loss, colour parameters (L*a*b*), while oxidation was assessed by determining the TBA-RS, carbonyl and aromatic amino acid content. Prolonged frozen storage of rhea meat decreased lightness (L*), yellowness (b*), and increased the discoloration parameter hue angle and redness a*. During storage, muscle IF was more prone to lipid and myoglobin oxidation than muscle GN. Cooking loss declined with the increase of storage time and was higher in GN than in IF muscle. With cooking, TBA-RS, carbonyl content, and aromatic amino acids (phenylalanine, tyrosine, and tryptophan) were highly affected, but the extent of oxidation ranged according to muscle and duration of frozen storage.