Meat Color Stability Research Articles

O-198 Meat colour and oxidative stability of lambs reared under conventional and holistic management systems

O-198 Meat colour and oxidative stability of lambs reared under conventional and holistic management systems

Ensuring sustainability in sensory sciences

Ensuring sustainability in sensory sciences

Relationships between growth-related traits with carcass and meat quality traits in Spanish Assaf suckling lambs

Suckling lamb meat is a relevant product in Mediterranean European dairy sheep farms, and the dairy breed Spanish Assaf is widely extended through the Iberian Peninsula. Knowledge of the influence of birth body weight (bBW) and growth rate on suckling lamb carcass and meat quality is scarce, but useful for breeding optimisation and product homogeneity. In turn, these growth-related traits of lambs might be affected by dietary restrictions of their dams. In this study, 34 male Assaf suckling lambs born from two groups of ewes that had been fed diets with different protein levels when they were prepubertal female lambs (17 lambs per group) were analysed. After birth, the suckling lambs were fed ad libitum on milk replacer until their sacrifice (10–12.5 kg live body weight). The quality traits evaluated in carcasses and meat were carcass compactness, fatness and jointing, meat composition, colour, texture and oxidative stability, and fatty acid profile. The dam group did not show significant effects on lamb growth characteristics or carcass and meat quality traits. The bBW factor showed a negative effect on leg subcutaneous fatness and a positive effect on the forequarter and shoulder percentages of the carcass. The bBW also resulted in increased moisture, lipid oxidation stability, and n-3 FA content (lowering the n-6/n-3 ratio) in the meat. Suckling lambs showing very low average daily gain (ADG) tended to present low carcass quality, i.e., higher bone percentage in the loin and low percentages of muscle or fat compared to those showing high ADG. Further studies are needed to confirm and explain the mechanisms of the significant effects reported here for bBW and ADG on the affected quality traits.

Study on meat color stability of Qinchuan cattle during post-slaughter storage

To study the stability of meat color in the post-slaughter storage process of Qinchuan cattle, three different bovine muscles, including longissimus dorsi (LD), knee round (KR) and psoas major (PM) muscles of Qinchuan cattle, were selected as research objects to determine the changes in meat color, myoglobin (Mb) relative content, pH, oxygen consumption rate (OCR), total iron, heme iron (HI) and other contents during storage. With the prolongation of the storage time, the relative content of oxymyoglobin (OxyMb) decreased, the relative content of metmyoglobin (MetMb) gradually increased, and muscle browning was due to the increase of a* value and hue value; Among them, HI and non-heme iron (NHI) reduced the stability of meat color by accelerating lipid oxidation, which was consistent with the results of Mb content and meat color index determining meat color stability. Therefore, the total iron content in muscles can also be used as an indicator of meat color stability.

Influence of LAB Fermentation on the Color Stability and Oxidative Changes in Dry-Cured Meat

Consumption of food products with a high level of compounds that are products of fat or protein oxidation is associated with the onset of various diseases. Therefore, this study estimated the level of oxidation in a fermented long-maturing tenderloin inoculated with lactic acid bacteria strains. To estimate the level of fat and protein exposure to oxidative factors, thiobarbituric acid reactive substances (TBARS), oxidation–reduction potential (ORP), oxygenation index (Oxi) as well as surface hydrophobicity (HS) of protein, and the content of free sulfhydryl (SH) groups were used as indicators of oxidation status. To validate the results, changes in the color of the products were determined using instrumental methods. This study confirmed the relationship between fat oxidation (based on TBARS) and oxidation of myoglobin as a protein representative (based on Oxi). Indeed, statistical analysis showed that TBARS, Oxi and SH were correlated with each other and could be used as indicators of oxidation in fermented products. The findings of this study also showed the use of LAB as starter cultures for meat fermentation may have an impact on the level of oxidation; in particular, the BAUER strain showed a protective effect on proteins in the final stages of the production of dry-cured pork loins.

Effect of the incorporation of polysaccharides from green alga Bryopsis plumosa on beef sausages quality.

Maintaining the quality and stability of functional meat products during storage is one of the major challenges of these products. The aim of this study was to evaluate the potential of polysaccharides extracted from green alga Bryopsis plumosa as a new natural additive in the formulation of beef sausages. In order to evaluate the impact of the incorporation of polysaccharides in beef sausages formulation, the physico-chemical, microbiological, and antioxidant properties were investigated during 12 days of storage at 4°C. Obtained data illustrated that the addition of this polymer in the formulation of beef sausages leads to a distinct antioxidant activity during 12 days of storage (4°C) with lower values in terms of lipid peroxidation compared to untreated samples. In addition, samples formulated with polysaccharides reduced the oxidation of Myoglobin, which consequently improved the color stability of meat during refrigerated storage. Furthermore, as compared to standard formulation, the addition of polysaccharides appears to have interesting antimicrobial potential that maintains sausage quality within a shelf life of 12 days. In conclusion, our results prove the efficiency of polysaccharides in providing more hygienic and safer meat products, which may suggest that PS could be used as a natural additive in functional foods.

Partial substitution of alfalfa hay by Berberis vulgaris leaf modulated the growth performance, meat quality and antioxidant status of fattening lambs.

Undoubtedly, global warming has caused a decrease in the production of agricultural commodities. This problem has increased the price of animal feed due to competition with human consumption. Meanwhile, the physiology of ruminants gives them the ability to use by-products and agricultural waste and supply their requirements for growth, maintenance and even production. Berberis vulgaris is a plant native to Iran, and after separating the fruit, its waste (mainly leaf) is unused and causes environmental pollution. The leaves of this plant contain significant amounts of phenolic compounds, alkaloids and anthocyanins that have antioxidant properties. This experiment was conducted with the aim of determining the chemical properties of barberry leaves, such as crude protein, phenolic compounds, tannins and alkaloids. The effects of substituting of B. vulgaris leaf (BVL) in the diet on performance characteristics of fattening Baluchi lambs were evaluated. The quality and antioxidant status of meat and blood parameters such as glucose, cholesterol, blood urea nitrogen and liver enzymes were investigated. A total of 21 male of 5-6 months old lambs with a mean body weight of 30.60±1.28kg were randomly assigned to one of three dietary treatments with different levels of BVL: 1-diet without BVL (control), 2-diet containing 7.5% BVL (BVL7.5), and 3-diet containing 15% BVL (BVL15; dry matter [DM] basis). Blood samples were harvested after overnight fasting from the jugular vein at 0, 28, 56 and 84 days. The lambs were slaughtered after 84 days of feeding trial andlongissimus dorsi(LD) muscle was dissected. Meat quality and antioxidant stability status were measured. 15% substitution of alfalfa hay by BVL (BVL15) increased DM intake) and decreased average daily gain (p≤ 0.05). The LD muscle (p≤ 0.05), liver (p≤ 0.01) and plasma (p≤ 0.05) samples of lambs fed either BVL7.5 or BVL15 displayed a greater total antioxidant capacity than that of lambs fed the control diet. Also, malondialdehyde concentration was decreased in plasma (p≤ 0.01) and LD muscle of lambs (p≤0.05) fed both BVL7.5 and BVL15. In addition, higher a* and C* values (p≤0.05) were observed in the meat of lambs fed BVL15 than those fed with the control, while the lightness (L*) in BVL15 was lower, compared to other experimental diets CONCLUSIONS: Overall, our results indicated that 7.5% substitution of alfalfa hay by BVL may positively modulate the antioxidant status of fattening lambs and improve the colour stability of meat without negative effects on performance characteristics.

Dietary α-lipoic acid supplementation improves postmortem color stability of the lamb muscles through changing muscle fiber types and antioxidative status

This study investigated the effect of dietary α-lipoic acid (600 mg/kg) supplementation on the postmortem color stability of the biceps femoris from lambs. The results showed that dietary α-lipoic acid supplementation increased a* and decreased b* and metmyoglobin (MMb) percentage of the biceps femoris with the time of storage (P < 0.05). The content of malondialdehyde (MDA) reduced with the time of storage after treatment with α-lipoic acid (P < 0.05). α-lipoic acid increased the myoglobin (Mb) content, and myosin heavy chain I (MyHC I) gene expression but decreased glycogen content, lactate dehydrogenase (LDH) activity, and MyHC IIb gene expression (P < 0.05). The T-AOC value, catalase (CAT) activity, and expression of SOD and CAT gene expression increased after α-lipoic acid treatment (P < 0.05). Therefore, dietary α-lipoic acid supplementation improved the meat color by regulating muscle fiber types and inhibited glycolysis. Moreover, α-lipoic acid maintained meat color stability by effectively inhibiting muscle oxidation via enhancing the antioxidant capacity

Economic Loss, Amount of Beef Discarded, Natural Resources Wastage, and Environmental Impact Due to Beef Discoloration

Any deviation from a bright-red color leads to a discounted price or beef is discarded. Limited data are currently available on the economic losses due to retail beef discoloration. Therefore, the objective of the study was to estimate economic losses, the amount of beef discarded, natural resource wastage, and environmental impact due to beef discoloration. One-year data of total beef sales, total beef discarded, and discounted sale values were collected from 2 national retail chains and 1 regional retail chain located in the Southern United States, representing data from 5,034 stores and 44 states. The US beef system life cycle parameters from published literature were used to calculate the impact of discarded meat on water and energy use and greenhouse gas emissions. The study noted that approximately 2.55% of beef is discarded because of discoloration. The results indicate that the US beef industry loses $3.73 billion annually owing to discoloration. The total amount of beef discarded per year in the US corresponds to 194.70 million kg, which represents wasting 780,000 animals and the associated natural resources used in their production. A 1% decrease in discolored beef in the US could reduce natural resource waste and environmental impact by 23.95 billion L of water, 96.88 billion MJ of energy consumed, and 0.40 million tons of carbon dioxide equivalent emission along the beef upstream value chain. Therefore, improving the color stability of meat could increase the sustainability of beef production and limit the waste of nutritious beef, so the application of novel technologies to mitigate color deterioration should be imperative.

Evaluating the impact of feeding dried distillers grains with solubles on Boer goat growth performance, meat color stability, and antioxidant capacity.

A total of 72 male Boer goat kids (21.7 ± 0.5 kg) were fed for 21 d with 3 kids per pen and 12 pens per treatment. Dietary treatments were: 0% inclusion of dried distillers grains with solubles (DDGS; 0% DDGS) or 33% DDGS inclusion (33% DDGS) and were provided ad libitum. Goats and feeders were weighed weekly to collect body weights (BW) and determine feed disappearance in order to calculate average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F). At the conclusion of the feeding study, a subset (n = 30; 2–3 goats from each pen representing six6 pens per treatment) of goats were harvested, carcasses evaluated, and loins were fabricated into 2.54 cm chops. Goat chop discoloration was evaluated by trained panelists and measured for L*, a*, and b* values on days 0, 4, 7, and 10 under retail display conditions. Samples were collected and analyzed for lipid oxidation, fatty acid profile, and hydrophilic and lipophilic antioxidant capacity. No evidence of differences was observed for final BW, ADFI, G:F, and carcass characteristics (P > 0.05). However, goats fed the 0% DDGS diet had greater ADG compared with those fed a diet containing 33% DDGS (P = 0.05). Overall, visual evaluation of discoloration, L*, a*, and b* as well as lipid oxidation data confirmed that feeding 33% DDGS to goats had no effect on goat chop discoloration and lipid oxidation (P > 0.10). However, all chops demonstrated a display effect, which they increased in visual discoloration and lipid oxidation and decreased in a* and b* values (P < 0.01) over the entirety of the 10-d period of retail display, regardless of the dietary treatments. As expected, feeding 33% DDGS to goats decreased relative percentage of multiple and total monounsaturated fatty acids, but increased relative percentage of multiple and total polyunsaturated fatty acids (PUFA; P < 0.05). The antioxidant capacity measurements showed no treatment difference in the hydrophilic portion (P > 0.10), but chops from the 33% DDGS treatment had greater lipophilic antioxidant activity compared with the 0% DDGS chops (P < 0.05). In conclusion, including 33% DDGS to the diet may negatively impact goat growth performance, but did not impact any carcass characteristics. Feeding a diet with 33% DDGS resulted in an increase in the PUFA content of goat chops but did not appear to impact meat color or lipid oxidation. The supposed negative consequence from increased PUFA is likely counterbalanced by the increased antioxidant capacity in the lipid component of meat, resulting in no difference in meat shelf-life.

Effect of different levels of organic zinc supplementation on pork quality

This study investigated the effect of two supplementation levels of zinc glycinate (ZnGly) on performance, carcass characteristics, and meat quality of growing-finishing pigs. Thirty pigs (bodyweight: 61 ± 4.0 kg) were assigned to three treatments and fed ad libitum for 56 days a diet supplemented with 0 (control), 45 (Zn45), or 100 mg/kg (Zn100) of ZnGly. The highest ZnGly supplementation lowered the average daily gain (P = 0.031); while, cold carcass weight did not differ between treatments. Both ZnGly levels reduced carcass chill loss (P < 0.001). Micromineral content, color stability, and fatty acid profile of meat were not altered by ZnGly. Superoxide dismutase activity was lowered by Zn45 compared to control (P = 0.007); while, catalase activity was enhanced by Zn100 (P = 0.003). Although ZnGly supplementation did not influence lipid oxidation in raw meat and in meat homogenates incubated with pro-oxidant catalysts, Zn45 limited lipid oxidation in cooked meat (P = 0.037). Our results demonstrated that supplementing pigs with 45 mg/kg of ZnGly could improve the oxidative stability of pork subjected to strong pro-oxidant conditions, but this effect needs to be further elucidated.

New polysaccharides extracted from Malcolmia triloba: Structure characterization, biological properties and application to beef meat preservation

In this study, the structure characteristics, the bioactivities, and the application to beef meat preservation of polysaccharides extracted from Malcolmia triloba were investigated. The characterization of polysaccharides named (PSMT) was investigated using Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), High Performance Liquid Chromatography (HPLC), Scanning Electron Microscopy (SEM), spectrum visible UV and nuclear magnetic resonance (13C NMR). The in vitro antioxidant activities of PSMT were evaluated by DPPH free radical assay, ferrous iron–chelating, reducing power and DNA nicking assay. Functional properties were determined based on Water Holding Capacity (WHC), Oil Holding Capacity (OHC), solubility, foaming capacity and emulsification properties. The experimental results suggested that PSMT exhibited strong antioxidant activities, and attractive techno-functional properties. In addition, the effect of PSMT on lipid oxidation of the ground beef meat was investigated during 9 days storage period at 4 °C. Indeed, obtained results showed significant decrease of TBARS values and inhibition of MetMb accumulation as well as significant inhibition of microbial proliferation as compared to control group during the period of storage. Furthermore, improvement of meat color stability, pH and moisture changes with highest values of heme iron were recorded.

Partial substitution of barley with maize meal or flaked meal in bovine diets: effects on fatty acid and α-tocopherol concentration and the oxidative stability of beef under simulated retail display

Context Different cereal grain sources may be used in beef production but little is known about their effects on beef quality. Aims This study evaluated fatty acid composition, α-tocopherol concentration and oxidative stability of beef from bulls fed barley or a combination of barley and either ground or toasted flaked maize. Methods Fatty acid composition, α-tocopherol concentration, lipid oxidation and colour stability were measured in beef from late maturing bulls finished on a barley-based concentrate (BC) or on the concentrate with barley partially replaced by either maize meal (MM) or flaked meal (FM). Samples of M. longissimus thoracis were subjected to simulated retail display (4°C) for 3, 7, 10 and 14 days in modified atmosphere packs (O2:CO2; 80:20). Muscle was analysed for fatty acid and α-tocopherol concentrations, colour stability and lipid oxidation. Key results There were differences in the fatty acid concentrations. Total fatty acids, monounsaturated fatty acids and saturated fatty acids were higher (P &lt; 0.05) in muscle from BC compared to FM bulls but neither were different to MM bulls. A decrease (P &lt; 0.05) in concentration following display was observed across all treatments for α-tocopherol, C15:1, C18:2 n-6c, C18:3 n-3, C20:3 n-6, C20:4 n-6, C22:2, C20:5 n-3, C22:5 n-3, C22:6 n-3, total polyunsaturated fatty acids (PUFA), n-6 PUFA, n-3 PUFA and highly peroxidisable PUFA. Lipid oxidation in muscle was higher (P &lt; 0.01) in muscle of FM compared to MM bulls after 14 days of refrigerated storage but neither were different to BC bulls. There was no difference (P &gt; 0.05) in colour stability of muscle due to dietary treatment. Conclusions Partial replacement of barley with maize in the diet of bulls influences muscle fatty acid concentration and profile, leading to a marginal increase in lipid oxidation with no detrimental effect on colour stability. Implications Toasted-flaked or ground maize may partially substitute for rolled barley in a concentrate ration without affecting colour stability of meat under retail display conditions. The slight increase in lipid oxidation, after prolonged storage, in beef from bulls fed flaked toasted maize is unlikely to be of significance from a product acceptability perspective.

The Effect of Different Sources of Selenium Supplementation on the Meat Quality Traits of Young Charolaise Bulls during the Finishing Phase.

The aim of the study was to compare the effects of sodium selenite (SS), selenium yeast (SY), and hydroxy-selenomethionine (OH-SeMet) on the meat quality and selenium (Se) deposition of finishing beef cattle. Sixty-three bulls were distributed over 3 treatments and fed SS, SY, or OH-SeMet at 0.2 mg kg−1 dry matter (DM) for 60 d. None of the Se sources affected the growth performance or carcass characteristics. OH-SeMet showed a higher Se transfer to the meat than SS or SY (p < 0.01). SY and OH-SeMet reduced the shear force of the meat (p < 0.0001), improved pH (p < 0.001), and reduced the drip losses (p < 0.001) and the lipid oxidation of the meat (p < 0.001). During 8 d of storage, OH-SeMet showed higher levels of meat lightness (L*) and yellowness (b*) than SS (p < 0.001), while the SY meat showed a higher L* than SS, albeit only on d 6. OH-SeMet improved b*, compared to SS, and also compared to SY on days 4, 7, and 8 (p < 0.001). Supplementing beef with SY and OH-SeMet improved several meat quality parameters. OH-SeMet appears to be the most effective strategy to improve the Se content and color stability of beef cattle meat.

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

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

Lipid Oxidation and Colour Stability of Lamb and Yearling Meat (Muscle Longissimus Lumborum) from SheepSupplemented with Camelina-Based Diets after Short-,Medium-, and Long-Term Storage.

This study investigated the impact of feeding pelleted diets containing camelina (Camelina sativa L. Crantz) hay (CAHP) or camelina meal (CAMP) as a supplement compared with a control pellet (CONP) diet, without vitamin E fortification. The fatty acid profile, retail colour, and lipid oxidative stability of lamb and yearling meat (m. longissimus lumborum) stored for short-, medium-, or long-periods (2 days (fresh), 45 days and 90 days) under chilled to semi-frozen conditions were determined. The CAMP diet altered key fatty acids (p < 0.05) in a nutritionally beneficial manner for human health compared to the other diets, with increased total omega-3, decreased omega-6 fatty acids and decreased omega-6/omega-3 ratio of muscle. Muscle vitamin E concentration was lower (p < 0.05) for both camelina diets (CAMP and CAHP) when compared with the CONP diet, with the average concentrations less than 1 mg/kg muscle for all three treatments. Animal type and storage length were factors that all affected (p < 0.05) colour and lipid oxidative stability of meat. These results emphasise the importance of vitamin E concentration in meat stored for extended periods under semi-frozen conditions to maintain desirable meat colour during retail display, and to avoid off-flavour development of the cooked meat.

Effects of coenzyme Q 10 and sodium succinate on color stability of minced pork during refrigerated storage

The objective of the study was to investigate the effects of coenzyme Q10 (CoQ10) and sodium succinate (SS) on the redness and thiobarbituric acid reactive substances (TBARS) of minced pork under 4 ± 1°C for 9 days. Different dosages of CoQ10 and SS were added to the minced pork, respectively. The results showed that CoQ10 or SS addition could retard the decrease of a* value effectively. The TBARS value decreased significantly with CoQ10 (0.002%–0.008%) or SS addition. The optimal levels of CoQ10 and SS addition were 0.006% and 0.04%, respectively. Compared to adding individually, the combination addition of 0.006% CoQ10 and 0.04% SS could make the a* value of minced pork more stable during storage, while the TBARS value and metmyoglobin content decreased significantly (p < .05). CoQ10 and SS can be used to improve the color stability of minced pork during storage by inhibiting lipid oxidation and metmyoglobin formation. Practical applications The discoloration of minced pork during storage affects edible quality and commercial value seriously. The process of color change can be effectively delayed by adding various antioxidants. Due to potential health risks of synthetic antioxidants, the demand for natural antioxidants has been increased. Coenzyme Q10 is one of the most consumed nutritional supplements, and succinate can improve meat color stability as a Krebs cycle substrate. The combination addition of coenzyme Q10 and sodium succinate can retard redness decrease, as well as inhibit lipid oxidation of minced pork during refrigerated storage. The practical implication of this study is that coenzyme Q10 and sodium succinate can be used as promising food additives to improve color stability and extend shelf life of meat or meat products.

The Effects of Carbon Monoxide Treatment on the Physical and Chemical Qualities of Tuna Steak during Iced Storage

Injection or modification of the atmosphere in the meat packaging by carbon monoxide (CO) has been known to retain the color stability of red meat including those of tuna. The red color in tuna meat has been commonly used as a freshness indicator by consumers, especially those for raw consumption. However, other information on the freshness level in fish, in addition to color, is also important to assess in the food safety of marine and fisheries products. This study aims to evaluate the effects of CO on the chemical and physical properties of tuna steak during storage on ice. This study was conducted using bigeye tuna (Thunnus obesus) as the raw material. The tuna was cut into loins to form steaks and divided into two groups, one group without CO injection or control, and another group was injected with CO. Both CO-treated tuna steak and control were preserved in a cool-box filled with ice for 14 days. The observation was conducted every two days by determining color (chromameter method), sensory preference (hedonic method), and several chemical parameters, including total volatile base (TVB), K value, and histamine content that related to the spoilage process. Results showed that after 14 days of preservation in iced storage, the reddish color of CO-treated tuna steak was retained, whereas that of control turned brown. In the sensory tests, the panelists preferred the CO-treated tuna steak to control due to its reddish color. There were no significant differences between the content of TVB accumulation and the K value in CO-treated tuna steak and the control. Furthermore, the K value of CO-treated tuna steak and control reached the rejected level on day 14. The difference between CO-treated tuna steak and control was based on the content of histamine, where that of control was significantly higher than tuna steak treated with CO. Therefore, this research showed that the effects of CO treatment were only on the appearance of the steak; meanwhile, the deterioration process in fish is generally unaffected. Precautions are thus needed for consumers, since color may not be the only factor that indicates the freshness of tuna steak.

Effects of sous vide vs grilling methods on lamb meat colour and lipid stability during cooking and heated display

The present study compared the effect of grilling (150 °C until 72 °C core temperature) and sous-vide (SV) cooking (75 °C for 35 min in a water bath under vacuum) on lamb patties immediately after cooking and after 4 h display at 65 °C. Both methods produced patties with similar (P > 0.05) weight loss, and moisture and fat contents. SV-cooking prevented (P < 0.05) the formation of thiobarbituric acid reactive substances (TBARS) and oxysterols compared to grilled patties, which showed a larger proportion of highly peroxidisable polyunsaturated fatty acids. Heated display induced dehydration, surface darkening and a reduction in the hexanal/3-methylbutanal ratio, suggesting the progression of Maillard reactions. Moreover, TBARS and some lipid oxidation-derived volatiles increased (P < 0.001), while cooked-meat aroma compounds were reduced (P < 0.001). SV-cooking inhibited (P < 0.05) the formation of malondialdehyde, and 7α- and 7β-hydroxycholesterol, and lowered the cholesterol oxidation ratio during heated display. Overall, SV-cooking may be considered a healthier way of cooking when lamb meat is to be kept warm for considerable periods before consumption.

Essential oil from pistachio by-product: potential biological properties and natural preservative effect in ground beef meat storage

Essential oil was extracted for the first time from pistachio by-product (EOPB) by hydrodistillation then analysed by gas chromatography-mass spectrometry (GC–MS). Forty two different components were identified in EOPB. The major components were E-9-Octadecen-1-ol acetate, 11-Hexacosyne, 1-Eicosanol, 3-Eicosanol and 2-Methyl-EE-3,13-Octadecane. The antioxidant and antibacterial activities of EOPB were also investigated. Therefore, EOPB displayed high antioxidant activity, in terms of DPPH-radical scavenging effect (IC50 = 4.6 mg/ml), β-carotene bleaching inhibitory effect (IC50 = 2.7 mg/ml) and 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) free radical scavenging effect (IC50 = 0.2 mg/ml). The antibacterial activity of EOPB was also tested against eight strains. The results indicated that EOPB has the highest activity against Salmonella thyphi, Enterococcus faecalis and Escherichia coli at the concentration of 100 mg/ml. Finally, the EOPB applications as food preservatives were studied. Indeed, the effect of different percentages (0.1 and 0.5%, w/w) of EOPB on thiobarbituric acid reactive substances (TBARS), meat color, and microbiological parameters of ground beef meat stored at 4 °C for 9 days was evaluated. The findings showed a reduction in lipid oxidation, meat color stability and an inhibition of bacterial growth in minced beef meat containing EOPB. In summary, the results suggested that EOPB can be used as natural preservatives for future application in meats industries.