Electron beam irradiated almond skin powder inhibition of lipid oxidation in cooked salted ground chicken breast

Antioxidant ability of electron beam irradiated almond skin powder (ASP) in cooked refrigerated ground chicken breasts (GCB) was investigated. Phenolic compound identification, total phenols and metal binding ability was determined. GCB were treated with irradiated ASP at 10, 20 and 30 kGy and tested against a positive (with TBHQ) and negative control (GCB without ASP or TBHQ) for colour, conjugated dienes (CD), TBARS and hexanal content during one week of refrigerated storage. Irradiation had no effect on total phenols, but resulted in greater metal chelation. Addition of ASP decreased hunter L* value in GCB. The 10 kGy ASP decreased lipid oxidation to the greatest extent (35.5–52.3%, 44.0–84.0%, and 74.9–87.4% decreases in CD, TBARS and hexanal formation, respectively) as compared to the negative control over one week of refrigerated storage. In general, cooked refrigerated GCB with ASP had lower oxidation products as compared to the negative control.     

Inhibition of lipid oxidation in refrigerated and frozen salted raw minced chicken breasts with electron beam irradiated almond skin powder

Antioxidant effects of electron beam irradiated almond skin powder (ASP) in raw minced chicken breasts (MCB) during refrigerated and frozen storage were studied. MCB samples were treated with BHT, non-irradiated ASP (0 kGy), irradiated ASP (10 kGy, 20 kGy and 30 kGy) and compared to MCB without antioxidants. Colour was determined on initial and final day of analysis while conjugated dienes (CD), peroxide values (POV), TBARS and hexanal content were evaluated periodically for 12 days of refrigerated storage and seven months of frozen storage. ASP addition lowered L* values compared to MCB without ASP or BHT. During refrigerated storage, MCB containing ASP had decreased formation of lipid oxidation products ranging from 0 to 66%, 7 to 24%, 0 to 37% and 4 to 71% reduction in POV, CD, TBARS and hexanal content, respectively, as compared to MCB without antioxidants over duration of study. A 15–65%, 3–25%, 14–50% and 28–82% reduction in POV, CD, TBARS and hexanal content, respectively, for frozen MCB was detected.     

Inhibition of lipid oxidation in refrigerated and frozen salted raw minced chicken breasts with electron beam irradiated almond skin powder

Antioxidant effects of electron beam irradiated almond skin powder (ASP) in raw minced chicken breasts (MCB) during refrigerated and frozen storage were studied. MCB samples were treated with BHT, non-irradiated ASP (0 kGy), irradiated ASP (10 kGy, 20 kGy and 30 kGy) and compared to MCB without antioxidants. Colour was determined on initial and final day of analysis while conjugated dienes (CD), peroxide values (POV), TBARS and hexanal content were evaluated periodically for 12 days of refrigerated storage and seven months of frozen storage. ASP addition lowered L* values compared to MCB without ASP or BHT. During refrigerated storage, MCB containing ASP had decreased formation of lipid oxidation products ranging from 0 to 66%, 7 to 24%, 0 to 37% and 4 to 71% reduction in POV, CD, TBARS and hexanal content, respectively, as compared to MCB without antioxidants over duration of study. A 15–65%, 3–25%, 14–50% and 28–82% reduction in POV, CD, TBARS and hexanal content, respectively, for frozen MCB was detected.     

Antioxidant Properties of Natural Plant Extracts Containing Polyphenolic Compounds in Cooked Ground Beef

Thiobarbituric acid‐reactive substances (TBARS) values, hexanal content, and sensory analysis were used to evaluate the effectiveness of selected natural antioxidants to reduce warmed‐over flavor (WOF) development in cooked ground beef. The control without added antioxidant showed the highest TBARS value, hexanal content, and WOF scores. Grape seed extract (ActiVin^TM) and pine bark extract (Pycnogenol®) significantly improved the oxidative stability of cooked beef. Compared to the control, ActiVin^TM, Pycnogenol®, and oleoresin rosemary reduced the hexanal content by 97%, 94% and 73% after 3 d of refrigerated storage, respectively. WOF scores showed a similar pattern as TBARS values and hexanal contents. TBARS values, WOF scores, and hexanal contents were all well correlated.     

Fat Content Influences the Color, Lipid Oxidation, and Volatiles of Irradiated Ground Beef

ABSTRACT:  Ground beef with 10%, 15%, or 20% fat were added with none, 0.05% ascorbic acid + 0.01%α-tocopherol, or 0.05% ascorbic acid + 0.01%α-tocopherol + 0.01% sesamol, and irradiated at 0 or 2.5 kGy. The meat samples were displayed under fluorescent light for 14 d at 4 °C. Color, lipid oxidation, volatiles, oxidation-reduction potential (ORP), and carbon monoxide (CO) production were determined during storage. Irradiation increased lipid oxidation and total volatiles of ground beef regardless of fat contents. Ascorbic acid +α-tocopherol + sesamol treatment was the most effective in reducing lipid oxidation during storage. The production of ethanol in nonirradiated ground beef increased dramatically after 7 d of storage due to microbial growth. Total aldehydes and hexanal increased drastically in irradiated control over the storage period, but hexanal increased the most by irradiation.  L *-values was decreased by irradiation, but increased in all meat regardless of fat contents as storage period increased. Irradiation reduced the redness, but fat contents had no effect on the  a *-value of ground beef. Sesamol lowered, but ascorbic acid +α-tocopherol maintained the redness of irradiated beef up to 2 wk of storage. The yellowness of meat was significantly decreased by irradiation. The reducing power of ascorbic acid +α-tocopherol lasted for 3 d, after which ORP values increased. Irradiation increased CO production regardless of fat content in ground beef. In conclusion, up to 20% fat had no effect on the quality change of irradiated ground beef if ascorbic acid +α-tocopherol was added.     

Antioxidant activity of carrot juice in gamma irradiated beef sausage during refrigerated and frozen storage

The antioxidant activity of carrot juice in gamma irradiated beef sausage was studied. Four batches of beef sausage were prepared, in which the first batch was formulated with water as the control. The other batches were formulated with unconcentrated carrot juice, carrot juice concentrated by 35% and 60%, respectively. Samples were irradiated at doses of 0, 3 and 4.5 kGy. Then the extent of oxidation in raw sausages was determined during refrigerated and frozen storage through the determination of peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) for lipid oxidation and carbonyl content for protein oxidation. The raw sausages were sensory evaluated during storage for colour, appearance and odour, while the grilled samples were sensory evaluated for their colour, odour, taste, texture and juiciness post-treatment only. Irradiation and storage significantly increased the PV, TBARS and carbonyl content in the samples formulated with water. The carrot juice significantly decreased the oxidative processes in the samples proportionally to the juice’s concentration. Furthermore, the sausages that were formulated with carrot juice had a high acceptable sensory scores as compared with the control samples.     

Combination effect of sodium lactate and irradiation on color,lactic acid bacteria,lipid oxidation and residual nitrite in Chinese sausages during storage at 25 °C

Chinese sausages, with the addition of 0 or 2% sodium lactate, were vacuum‐packaged and stored overnight at 4°C. Refrigerated sausages were gamma‐irradiated at 0, 3 or 5 kGy absorbed dose. Meat samples were stored at 25°C for up to 30 days. Color, lactic acid bacteria, pH, lipid oxidation and residual nitrite were determined during storage. Irradiated samples were reduced in redness as a result of irradiation and storage time. Irradiation at 5 kGy alone or in combination with 2% sodium lactate and irradiation at 3 kGy could completely inhibit lactic acid bacterial growth. Thiobarbituric acid reactive substances (TBARS) values decreased as the pH values of samples increased. Sodium lactate decreased TBARS values of all samples and protected against a decrease of residual nitrite during storage. Irradiation reduced residual nitrite in Chinese sausage, and residual nitrite decreased with increased time. Copyright © 2004 Society of Chemical Industry     

Effects of plant extracts on microbial growth, color change, and lipid oxidation in cooked beef

The effects of butylated hydroxyanisole/butylated hydroxytoluene (BHA/BHT), grape seed extract (ActiVin), pine bark extract (Pycnogenol), and oleoresin rosemary (Herbalox) on microbial growth, color change, and lipid oxidation were investigated in cooked ground beef. When compared to the control, 1.0% ActiVin and Pycnogenol) effectively reduced the numbers of Escherichia coli O157:H7 and Salmonella Typhimurium, and retarded the growth of Listeria monocytogenes and Aeromonas hydrophila. Pycnogenol resulted in reductions of 1.7, 2.0, 0.8, and 0.4 log CFU/g, respectively, in numbers of E. coli O157:H7, L. monocytogenes, S. Typhimurium, and A. hydrophila, respectively, after 9 days of refrigerated storage. The color of cooked beef treated with ActiVin was less light (L*), more red (a*), and less yellow (b*) than those treated with BHA/BHT, Pycnogenol, and Herbalox. ActiVin and Pycnogenol effectively retained the redness in cooked beef during storage. The control showed significantly higher thiobarbituric acid-reactive substances (TBARS) and hexanal content over storage. BHA/BHT, ActiVin, Pycnogenol, and Herbalox retarded the formation of TBARS by 75%, 92%, 94%, and 92%, respectively, after 9 days, and significantly lowered the hexanal content throughout the storage period. Results of this work show that ActiVin and Pycnogenol are promising additives for maintaining the quality and safety of cooked beef.     

Effect of γ-Oryzanol on the Flavor and Oxidative Stability of Refrigerated Cooked Beef

ABSTRACT: γ-Oryzanol and α-tocopherol were added to beef patties as natural antioxidants. Beef patties containing 100 ppm γ-oryzanol had higher oxidative stability ( P <0.05) during storage at 4 °C than did beef patties with other antioxidants and without antioxidant. Thiobarbituric acid-reactive substances (TBARS) values, warmed over flavor (WOF) scores, C-7 oxidized cholesterol derivatives (OCDs), and concentrations of both hydroperoxide and hexanal in the cooked beef containing γ-oryzanol were significantly lower than those of other treatments ( P < 0.05). All variables had similar trends during the refrigerated storage. Significant correlations were found between TBARS and C-7 OCDs, TBARS and WOF, hydroperoxide and hexanal, and hexanal and WOF ( P < 0.05).     

迷迭香提取物对牛肉丸冻藏过程中脂肪氧化和品质特性的影噢

将不同浓度的迷迭香提取物（0、0.02%、0.04%和0.06%）添加到牛肉丸中,并以0.02%丁基羟基茴香醚（BHA）做对照,测定迷迭香处理组和对照组牛肉丸在冻藏过程中的过氧化物值（PV）、硫代巴比妥酸值（TBARS）、色差值（L*值、a*值）、保水性和质构特性,并对牛肉丸进行感官评价,考察迷迭香提取物对牛肉丸脂肪氧化和品质特性的改善作用。结果表明,迷迭香提取物可显著降低冻藏牛肉丸的PV值和TBARS值,抑制牛肉丸的脂肪氧化程度;同时,提高牛肉丸的a*值,使其保持良好的色泽;迷迭香提取物还能降低牛肉丸的蒸煮损失和解冻损失,改善牛肉丸的保水性;硬度、弹性和咀嚼性等质构特性也得到改善;感官评价结果显示,迷迭香处理组牛肉丸的感官评分较高,具有良好的感官品质。因此,迷迭香提取物具有抑制冻藏肉牛丸制品脂肪氧化和改善其食用品质的潜在应用价值。     

电子束辐照剂量率对真空包装冷鲜牛肉品质的影响

研究了电子束辐照剂量率对真空包装冷鲜牛肉品质的影响,为电子束辐照在冷鲜肉保鲜中的应用提供理论依据。将真空包装的冷鲜牛肉在2 k Gy的辐照剂量下分别经不同剂量率(0、700、1500、2500、3500 Gy/s)处理,然后再置于2℃冰箱内贮存15 d。贮藏期内分别对微生物指标(菌落总数(TBC))和理化指标(挥发性盐基氮含量(TBA-N)、硫代巴比妥酸值(TBARS)、过氧化值(POV)、巯基(SH)、二硫键(SS)、色泽(L*和a*))进行测定,对比不同剂量率处理对辐照效果的影响。结果表明,在2 k Gy的辐照剂量下,在一定剂量率范围内随着剂量率的不断增大,冷鲜牛肉的TBC、TVB-N、TBARS、POV、SS和L*值均显著降低,而SH和a*值增加(p0.05)。综合分析各指标说明电子束辐照剂量率对冷鲜牛肉品质有显著的影响;同时可得出,在2 k Gy的辐照剂量下,剂量率为2500Gy/s处理组,贮藏15 d后,细菌总数5.161 log(CFU/g),TVB-N值为16.6 mg/100g,POV值为1.126 meq/kg,TBARS值为0.218 mg/100g,SH和SS分别为0.395和0.379 mmol/g pro,L*和a*值分别为40.34和19.57,综合辐照效果最佳。     

The use of natural herbal extracts for improving the lipid stability and sensory characteristics of irradiated ground beef

Ground Longissimus dorsi of beef were treated with herbal extracts of marjoram, rosemary and sage at concentration of 0.04% (v/w), radiation (2 or 4.5 kGy) or their combination. Treated samples were stored at 5 °C and analyzed periodically for thiobarbituric acid reactive substances (TBARS), sensory characteristics and psychrotrophic bacterial counts during storage for 41 and 48 days for samples treated at 2 and 4.5 kGy respectively. Results demonstrated a significant benefit of the addition of herbal extracts to the ground beef prior to irradiation. All three extracts significantly (P < 0.05) lowered the TBARS values and off-odor scores and significantly (P < 0.05) increased color and acceptability scores in all samples with marjoram being the most effective. The combination treatment with herbal extracts plus irradiation resulted in extension of the shelf life of samples treated with 2 kGy by one week and samples treated with 4.5 kGy by two weeks, over that treated with irradiation alone. In conclusion, the addition of herbal extracts can minimize lipid oxidation, improve color and decrease off-odor production in irradiated ground beef.     

Effect of gamma radiation on refrigerated mechanically deboned chicken meat quality

Samples of mechanically deboned chicken meat (MDCM) were irradiated in the frozen form with doses of 0.0, 3.0 and 4.0 kGy, stored at 2±1?°C and evaluated for their sensory characteristics, color, thiobarbituric acid reactive substances (TBARS) and total psychrotrophic bacterial count for up to 12 days. The sensory analysis showed that volatile compounds associated with the odor irradiation produces, were dissipated from the samples of irradiated MDCM during storage and that the oxidation odor perceived in the samples irradiated with doses of 3.0 and 4.0 kGy was more pronounced (P<0.05) than in the non-irradiated samples, as from the 8th and 12th day of refrigeration, respectively, in agreement with the TBARS values. Irradiated MDCM showed higher values (P<0.05) for a(?) (redness) than the non-irradiated samples as from the 4th day under refrigeration. Considering the sensory analyses, color, psychrotrophic bacterial counts and TBARS analyses as a whole, the MDCM samples irradiated with doses of 0.0, 3.0 and 4.0 kGy were acceptable under refrigerated storage for 4, 10 and 6 days, respectively.     

Application of electron‐beam irradiation pasteurization of ground beef,from steers fed vitamin E fortified diets: microbial and chemical effects

The effects of vitamin E supplementation of diets and electron‐beam irradiation (EBI) processing of ground beef patties on microbial and chemical qualities were investigated during 21 days of storage at 4 °C. Oxidative damage to lipids induced by EBI in ground beef patties containing different fat contents was first determined at 3 day intervals throughout a 7 day storage period at 4 °C. Significantly (P ≤ 0.05) higher values for thiobarbituric acid reactive substances (TBARS) were detected in beef patties of higher fat content (ie at 17 and 30%), which was further enhanced by irradiation at 5 kGy. Since lipid oxidation proceeded to a greater extent in beef patties with higher fat levels, ground beef patties of 30% fat were prepared from steers fed basal (diet I) or basal + 500 IU (diet II) of the antioxidant (vitamin E) supplemented diets. Plasma vitamin E concentrations in cattle fed diets I and II were 1.58 ± 0.42 µg ml^?1 and 2.49 ± 0.40 µg ml^?1 respectively. Patties were processed with three doses (2, 5, or 10 kGy) of EBI and compared with non‐irradiated patties. Microbial indices monitored at 3 day intervals included total aerobic plate count, psychrotrophic counts, and total coliform and Escherichia coli counts. Bacterial growth in ground beef patties stored at 4 °C was significantly (P ≤ 0.05) reduced by EBI at 2 kGy dose. Complete inhibition of bacteria occurred at 5 kGy or higher (P ≤ 0.05) dosage of EBI over 21 days of storage at 4 °C. Quality indices monitored at 3 day intervals throughout a 21 day storage (4 °C) study involving 30% fat ground beef patties made from steers fed vitamin E supplemented diets I and II included TBARS and colour. Results indicated that irradiation at the highest dosages was associated with higher (P ≤ 0.05) TBARS values, which in turn corresponded to lower linoleic acid content. With all three levels of irradiation, Hunter a values of beef patties decreased (P ≤ 0.05) significantly. Lipid oxidation was significantly (P ≤ 0.05) retarded in stored beef patties derived from cattle fed vitamin E (diet II). Copyright © 2003 Society of Chemical Industry     

Antioxidative activity of carnosine in gamma irradiated ground beef and beef patties

The activity of carnosine as a natural antioxidant in gamma irradiated ground beef and beef patties was studied. Samples of ground beef, in the absence and presence of 0.5% or 1.0% carnosine, as well as raw and cooked beef patties prepared with 1.5% salt (NaCl), in the absence and presence of 0.5% or 1.0% carnosine, were gamma irradiated at doses of 0, 2, and 4 kGy. The extent of oxidation in irradiated and non-irradiated samples of ground beef and raw beef patties was then determined during refrigerated (4 ± 1 °C) and frozen (−18 °C) storage, while determined for cooked beef patties during refrigerated storage only. Moreover, the determination of metmyoglobin (MetMb) accumulation and sensory evaluation for the visual color were carried out for samples of ground beef and raw patties. The results indicated that salt or salt and cooking accelerated the oxidative processes and significantly increased the peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) in the prepared non-irradiated samples. However, salt slowed down the accumulation of MetMb in raw patties. Irradiation treatments and storage in the absence of carnosine significantly (P < 0.05) increased the PV and TBARS in samples, at higher rates in salted or salted and cooked beef. Moreover, irradiation and storage significantly (P < 0.05) increased the formation of MetMb in ground beef and raw patties in the absence of carnosine. Addition of carnosine significantly (P < 0.05) reduced the oxidative processes and MetMb formation (proportionally to the used concentration) in samples post-irradiation and during storage. Furthermore, carnosine exerted significant efficacy in maintaining an acceptable visual red color post-irradiation and during storage of ground beef and raw patties. These results demonstrate that carnosine can be successfully used as a natural antioxidant to increase the oxidative stability in gamma irradiated raw and cooked meat products.     

电子束辐照进口冷冻牛腩的剂量分布及感官特性研究

目的 确认电子束辐照冷冻牛腩的剂量分布特性,研究不同剂量电子束辐照对冷冻牛腩的杀菌效果及辐照后产品色泽、风味、质构等感官指标的变化,为冷冻牛腩辐照杀菌的工艺设定和质量控制提供技术参考依据。方法 对不同厚度的冷冻牛腩块分别用8 kGy进行单面及双面电子束辐照,检测其内部剂量分布,确定辐照适宜的产品厚度,在此基础上用0 kGy、2 kGy、4 kGy不同剂量对商品包装（1 kg/袋,最大厚度不超过8 cm）的冷冻牛腩进行电子束双面辐照,检测菌落总数、霉菌和酵母、大肠菌群,同时利用色差仪、电子鼻、质构仪检测冷冻牛腩及其熟制品的色泽、风味、质构等感官指标。结果 单面电子束辐照冷冻牛腩的内部剂量呈先上升后下降趋势,快速下降发生在3.5~5 cm深度区域,产品厚度3.5 cm时剂量不均匀度为1.57。双面辐照可增加电子束穿透深度,8.1cm厚度双面辐照的剂量不均匀度为1.62。冷冻牛腩中菌落总数、霉菌和酵母、大肠菌群均有检出,电子束辐照可显著降低冷冻牛腩微生物水平,商品包装的冷冻牛腩经2 kGy电子束双面辐照后无大肠菌群检出,菌落总数、霉菌和酵母分别较未辐照处理降低98.8%和89.2%。电子束辐照对冷冻牛腩及其熟制品风味、质构无不良影响,4 kGy处理显著还提高了冷冻牛腩回复性,但电子束辐照导致冷冻牛腩色泽参数a值和b值显著下降,且剂量越高下降幅度越大。电子束辐照对色泽的影响程度在冷冻牛腩熟制后降低,2 kGy处理的b值显著高于未辐照处理,其它各处理的a值、b值与未辐照处理均无显著差异。结论 8.1cm厚度冷冻牛腩电子束双面辐照的剂量不均匀度为1.62,冷冻牛腩2 kGy双面辐照后无大肠菌群检出,菌落总数显著降低,风味、质构无不良变化,但色泽参数a、b值显著下降,产品红色消退,熟制可以降低辐照对色泽的不良影响。     

Chemical and Sensory Quality Preservation in Coated Almonds with the Addition of Antioxidants

Almonds provide many benefits such as preventing heart disease due to their high content of oleic fatty acid‐rich oil and other important nutrients. However, they are susceptible to oxidation reactions causing rancidity during storage. The objective of this work was to evaluate the chemical and sensory quality preservation of almonds coated with carboxymethyl cellulose and with the addition of natural and synthetic antioxidants during storage. Four samples were prepared: almonds without coating (C), almonds coated with carboxymethyl cellulose (CMC), almonds coated with CMC supplemented with peanut skins extract (E), and almonds coated with CMC and supplemented with butylhydroxytoluene (BHT). Proximate composition and fatty acid profile were determined on raw almonds. Almond samples (C, CMC, E and BHT) were stored at 40 °C for 126 d. Lipid oxidation indicators: peroxide value (PV), conjugated dienes (CD), volatile compounds (hexanal and nonanal), and sensory attributes were determined for the stored samples. Samples showed small but significant increases in PV, CD, hexanal and nonanal contents, and intensity ratings of negative sensory attributes (oxidized and cardboard). C had the highest tendency to deterioration during storage. At the end of storage (126 d), C had the highest PV (3.90 meqO₂/kg), and BHT had the lowest PV (2.00 meqO₂/kg). CMC and E samples had similar intermediate PV values (2.69 and 2.57 meqO₂/kg, respectively). CMC coating and the addition of natural (peanut skin extract) and synthetic (BHT) antioxidants provide protection to the roasted almond product.     

Combined effect of gamma irradiation,ascorbic acid,and edible coating on the improvement of microbial and biochemical characteristics of ground beef

This study was conducted to evaluate the combined effect of gamma irradiation and the incorporation of natural antimicrobial compounds in cross-linked films on the microbiological and biochemical characteristics of ground beef. Medium-fat (23% fat) ground beef patties were divided into three separate treatment groups: (i) control samples without additives, (ii) ground beef samples containing 0.5% (wt/wt) ascorbic acid, and (iii) ground beef samples containing 0.5% ascorbic acid and coated with a protein-based cross-linked film containing immobilized spice powders. Meat samples were irradiated at doses of 0, 1, 2, and 3 kGy and stored at 4 +/- 2 degrees C. Microbial growth (based on total aerobic plate counts [APCs] and total coliforms) was evaluated, as were the content of thiobarbituric acid-reactive substances (TBARS) and that of free sulfydryl groups. At the end of the storage period, Enterobacteriaceae, presumptive Staphylococcus aureus, presumptive Pseudomonas spp., Brochothrix thermosphacta, and lactic acid bacteria were enumerated. Regardless of the treatment group, irradiation significantly (P < or = 0.05) reduced the APCs. Irradiation doses of 1, 2, and 3 kGy produced immediate APC reductions of 2, 3, and 4 log units, respectively. An APC level of 6 log CFU/g was reached after 4, 7, and 10 days for samples irradiated at 1, 2, and 3 kGy, respectively. Lactic acid bacteria and B. thermosphacta were more resistant to irradiation than were Enterobacteriaceae and Pseudomonas. The TBARS and free sulfydryl contents were stabilized during postirradiation storage for samples containing ascorbic acid and coated with the protein-based cross-linked film containing immobilized spice powders.     

Reduction of Warmed-Over Flavor Volatiles from Freeze-Dried Lean by Supercritical CO2 Extraction

Supercritical carbon dioxide (SC-CO₂) was used to extract warmed-over flavor (WOF) volatiles from cooked, freeze-dried beef at 40°C and pressures of 10.3 MPa or 30 MPa after 2 days storage. WOF markers, hexanal, heptanal, octanal, nonanal, and 2,3-octanedione, were identified in the volatiles profile of precooked beef by dynamic headspace extraction and gas chromatography-mass spectrometry before and after CO₂ extraction. TBARS and levels of WOF markers increased over 2 days storage. There was a reduction in WOF markers at both extraction pressures. The higher pressure led to greater reduction of WOF markers (e.g., hexanal: 73.5%) than the lower pressure (e.g., hexanal: 60.3%), notably for heptanal and nonanal. SC-CO₂ may be applicable for reducing WOF volatiles from precooked meats.     

Effects of aging time and natural antioxidants on the color, lipid oxidation and volatiles of irradiated ground beef

Beef rounds aged for one, two, or three weeks after slaughtering were ground added with 0.05% ascorbic acid+0.01% α-tocopherol or 0.05% ascorbic acid+0.01% α-tocopherol+0.01% sesamol, placed on Styrofoam trays and wrapped with oxygen-permeable plastic film, and treated with electron beam irradiation at 0 or 2.5kGy. The meat samples were displayed under fluorescent light for 7d at 4°C. Color, lipid oxidation, volatile analysis, oxidation-reduction potential (ORP) and carbon monoxide (CO) production were determined at 0, 3, and 7d of storage. Irradiation increased lipid oxidation of ground beef regardless of their aging time and storage period. As aging time increased lipid oxidation increased. Adding sesamol increased the effectiveness of ascorbate and tocopherol combination in reducing lipid oxidation especially as aging and storage time increased. The redness of beef were decreased by irradiation and adding ascorbic acid and α-tocopherol before irradiation was effective in maintaining the redness of irradiated ground beef over the storage period. The combination of ascorbic acid+α-tocopherol to ground beef was more effective in reducing ORP than adding sesamol. Irradiation increased CO production from all ground beef regardless of aging time or additives treatments. Volatile sulfur compounds produced by irradiation at Day 0 disappeared over the storage period. Alcohol greatly increased in all nonirradiated beef, but volatiles aldehydes only in irradiated control beef. Antioxidant treatments were effective in reducing aldehydes in ground beef during storage.