Predicting the amount of carbon dioxide absorbed in meat

Carbon dioxide is commonly used in modified atmosphere packaging of meat and the gas is highly soluble in meat. Both intrinsic (pH, water and fat content) and extrinsic (CO₂ partial pressure, headspace to meat volume ratio and storage temperature) factors affect the amount of CO₂ absorbed in meat. A multi factorial packaging experiment using minced pork was carried out in order to evaluate the effect of such factors under realistic conditions and to develop models for prediction of the amount of absorbed CO₂. For most practical applications CO₂ partial pressure and headspace to meat volume ratio are the key factors determining CO₂ absorption in meat. For volume ratios of more than 2 L gas/kg meat, knowledge of the partial pressure of CO₂ was sufficient to predict the amount of absorbed CO₂.     

Display life of sheep meats retail packaged under atmospheres of various volumes and compositions

Longissmus dorsi loins were removed from Suffolk cross-breed lambs (4–9 months) and hoggets (15–20 months). The effect of package gas composition was investigated by packaging loins with gas mixtures containing 80:20:0, 60:20:20 and 60:40:0/O₂:CO₂:N₂ with a 2:1 headspace to meat volume ratio. The most effective gas mixture for prolonging shelf-life was used to study the effect of different headspace to meat volume ratios. Loins were packaged with a headspace to meat volume ratio of 2:1, 1.5:1 or 1:1. All modified atmosphere (MA) packs were held under refrigerated display conditions (4 °C, 616 lx) for 12 days. Loins were assessed for microbial, oxidative and colour stability and headspace composition every 3 days. The 80:20:0/O₂:CO₂:N₂ gas composition and the 2:1 headspace to meat volume ratio was the most effective packaging combination at maintaining and prolonging the attractive red colour of MA packaged lamb and hogget meat. 80:20:0/O₂:CO₂:N₂ resulted in significantly (p<0.01) higher Hunter a values in lamb. The 2:1 ratio gave higher visual assessment values in lamb and higher Hunter ‘a' values for hogget meat throughout the trial. The 2:1 ratio was the most effective at decreasing Pseudomonas and increasing the numbers of lactic acid bacteria in the total microbial load in both lamb and hogget meat. Lipid oxidation in lamb and hogget meat occurred at a slower comparative rate than discolouration or microbial growth and was not the major determinant of shelf-life. The 2:1 headspace to meat volume ratio was most effective at maintaining the initial gas mix in both lamb and hogget MA packs.     

Evaluation of the antioxidant potential of grape seed and bearberry extracts in raw and cooked pork

The effect of grape seed extract (GSE) and bearberry (BB), on lipid oxidation (TBARS, mg malondialdehyde (MDA)/kg muscle), colour (CIE ‘a’ redness value), pH, microbial status (log₁₀CFU colony forming units/g pork) and sensorial properties of cooked pork patties was investigated. GSE (0–1000 μg/g muscle) and BB (0–1000 μg/g muscle) were added to raw pork (M. longissimus dorsi) patties which were stored in modified atmosphere packs (MAP) (75% O₂:25% CO₂) for up to 12 days at 4 °C. Cooked pork patties were stored in MAP (70% N₂:30% CO₂) for up to 4 days at 4 °C. Mesophilic plate counts and pork pH were unaffected by GSE and BB. GSE and BB addition decreased (P < 0.05) lipid oxidation (TBARS) in raw pork patties on days 9 and 12 of storage, relative to controls. Antioxidant activity of GSE and BB was observed in cooked pork patties demonstrating the thermal stability of GSE and BB. The ‘a’ redness values of raw and cooked pork patties marginally increased with increasing GSE concentration. The sensory properties of cooked pork patties were unaffected by GSE and BB addition. Results obtained demonstrate the potential for using health promoting nutraceuticals in meat and meat products.     

Influence of packaging method and length of chilled storage on microflora, tenderness and colour stability of venison loins

Sections of venison loins (LD) weighing approximately 300 g from 12 red deer (Cervus elaphus) were packaged using four packaging methods: (a) vacuum packaging, (b) CO₂ flushed using a nylon containment film (CO₂-Nylon), (c) CO₂ flushed using an ultra-high barrier containment film (CO₂-UHB), and (d) CO₂ flushed using an aluminium foil laminate containment film (CO₂-Foil) and stored for 1, 6, 12 and 18 weeks at 0°C. Meat pH values were lower in all CO₂ flushed meat packages (P<0·05) than in vacuum packaged meat. Lactic acid bacteria and total anaerobic counts increased over storage time in all packages regardless of treatment up to values of log₁₀ 7·8 and 7·6 g⁻¹, respectively. Tenderness tended to increase as meat was stored for up to 18 weeks. Colour scores taken during simulated retail display indicated that colour deteriorated more rapidly when meat was stored for 12 and 18 weeks than for 1 and 6 weeks. Vacuum packaging and gas flushing (CO₂-Foil) resulted in higher initial colour scores than venison packaged in the CO₂-Nylon or CO₂-UHB materials. Venison stored for 18 weeks also exhibited a higher proportion of packages containing off odours, lower flavour desirability and flavour intensity scores as well as higher off flavour scores than meat stored for shorter times. The implications of these effects are discussed. Although there were few significant differences in microbial growth and sensory characteristics due to packaging method or containment film, vacuum packaging appeared to be the most economic and produced meat of better colour stability.     

小麦蛋白对钾盐替代猪肉熏煮香肠综合品质的调控作用

目的：为研究小麦蛋白对低盐猪肉熏煮香肠品质的调控规律,确定低盐条件下小麦蛋白的适用范围。方法：采用单因素实验,设计0～50%的KCl替代水平,添加0～8%的小麦蛋白,测定产品质构、色泽、出品率、保水性等品质指标;借助于方差分析、相关分析、主成分分析、回归分析等多元分析方法,研究小麦蛋白对低盐产品品质的影响规律,探讨熏煮香肠品质指标间的关系,构建综合品质评价方法,并进行应用研究。结果：在20%～30%等KCl低替代食盐比例下,6%～8%的小麦蛋白显著提高产品出品率和保水率;构建了小麦蛋白调控低盐猪肉香肠综合品质评价模型：Y₄=0.342×(0.127×Z₁+0.169×Z₂+……-0.110×Z₁₀-0.108×Z₁₁)+0.230×(0.328×Z₁-0.185×Z₂+……+0.115×Z₁₀+0.249×Z₁₁)+0.146×(-0.088×Z₁+0.315×Z     

Pressing and supercritical carbon dioxide extraction of walnut oil

The objective of this study was to evaluate the oil extraction process from walnut seeds by pressing followed by extraction with supercritical CO₂. In pressing experiments, a factorial arrangement was conducted in order to study the combined effects of seed moisture content (2.5%, 4.5% and 7.5%) and pressing temperature (25, 50 and 70 °C) on oil recovery and quality parameters. For all conditions tested, the oil quality compared well with that of cold-pressed walnut oil. Oil recovery increased significantly as moisture content raised. Highest oil recovery (89.3%) was obtained at 7.5% moisture content and 50 °C temperature. The cake resulting from pressing at these conditions was extracted with CO₂ in a high pressure pilot plant with single stage separation and solvent recycle. The effects of two different pressures (200 and 400 bar) and temperatures (50 and 70 °C) with regard to oil yield and quality, and time required for extraction were analyzed. At each condition, the extraction rate changed with the mass of solvent and extraction time. At first, the mass of oil extracted was determined by the oil solubility in CO₂ and a linear relationship was observed, where the slope results in the solubility of oil in CO₂ at the experiment conditions. After that, the extraction rate was governed by solubility and diffusion, and continuously decreased with time. The colour changed along the extraction from a whitish clear product to a yellow one. Tocopherol and carotenoid contents were significantly higher than those obtained by pressing. Extraction conditions did not affect significantly the fatty acid composition.     

Effect of carbon monoxide in modified atmosphere packaging, storage time and endpoint cooking temperature on the internal color of enhanced pork

The objective of this research was to evaluate the effects of gas atmosphere, refrigerated storage time, and endpoint temperature on internal cooked color of injection-enhanced pork chops. Enhanced chops were packaged in 0.36% CO/20.34% CO₂ (CO-MAP), 80% O₂/20% CO₂ (HO-MAP), or PVC-overwrapped (PVC-OW; controls), stored at 4 °C for 0, 12, 19 or 26 days, displayed for 2 days then cooked to six endpoint temperatures (54, 60, 63, 71, 77, and 82 °C). L^*, a^*, and b^* values, hue angle and chroma were determined on the internal cut surface of cooked chops. Chops packaged in CO-MAP had the highest a^* values; a^* value began increasing on day 14. The lowest hue angles occurred in chops cooked to lower endpoint temperatures. Chops in CO-MAP had lower hue angles and higher chroma than those in HO-MAP and PVC-OW. Above 71 °C, hue angle and chroma increased. Overall, CO-MAP packaged chops stored for longer time periods then cooked to lower endpoint temperatures appeared reddest. HO-MAP packaged chops were less red, did not change over time, and appeared more well done at lower endpoint temperatures than those in other gas atmospheres. CO-MAP packaged chops retained redness even after cooking at 82 °C.     

气调包装协同高功率脉冲微波对河蟹肉储藏期品质影响研究

为研究气调包装协同高功率脉冲微波对河蟹肉的保质效果,设置不同气体类型和组成比例(100％CO2、80％CO2+20％N2、50％CO2+50％N2、20％CO2+80％N2)以及协同高功率脉冲微波(作用频率200 Hz、时间6 min)处理,测定处理后河蟹肉在25℃贮藏期间菌落总数、挥发性盐基氮(total volat...     

Addition of tea catechins and vitamin C on sensory evaluation, colour and lipid stability during chilled storage in cooked or raw beef and chicken patties

The effects of addition of tea catechins (TC) and vitamin C (VC) on sensory evaluation, colour and lipid stability in cooked or raw beef and chicken meat patties during refrigerated storage were studied. Fresh beef striploin and chicken breast muscles were minced, following removal of external fat and connective tissue. Following mincing, beef and chicken were assigned to one of the following five treatments: control (meat treated with no antioxidant); TC200, meat plus 200 mg TC/kg muscle; TC400, meat plus 400 mg TC/kg muscle; VC200, meat plus 200 mg VC/kg muscle, VC400, meat plus 400 mg VC/kg muscle. Sodium chloride (1%) was added to all samples. Patties (125 g portions), formed from the above-treated minced meat, were oven cooked, cooled, and packaged in 30% CO₂:70% N₂. Fresh raw beef and chicken patties were packaged in 80% O₂:20% CO₂. All samples were stored for up to 7 days under fluorescent lighting at 4 °C. Sensory parameters (colour, flavour, taste, tenderness and overall acceptability) were evaluated on cooked beef and chicken patties after 1, 3 and 6 days of storage. Surface colour (Hunter L, a and b values), and lipid oxidation (2-thiobarbituric acid reactive substances) were measured on days 1, 3 and 6 of storage for cooked meats and on days 2 and 7 for raw beef and chicken. Tea catechins addition (200 or 400 mg/kg) to minced meat caused (P < 0.05) discolouration in cooked beef and chicken meat patties and significantly reduced (P < 0.001) lipid oxidation in cooked or raw beef patties compared to the control. Beef, either raw or cooked, was more susceptible (P < 0.01) to oxidation compared to chicken. Raw meat stored in high oxygen conditions was more susceptible to lipid oxidation than cooked meat stored in anaerobic conditions. Tea catechins treatments (TC200 and TC400) inhibited (P < 0.05) lipid oxidation in raw beef to a greater extent than vitamin C treatments (VC200 and VC400). These results indicate that tea catechins are potent natural antioxidants and exhibit greater antioxidant efficacy compared to vitamin C.     

Effect of redox potential on Bacillus subtilis and Bacillus licheniformis in broth and in pasteurized sausage mixtures

Bacillus licheniformis (a facultatively anaerobe) and B. subtilis (aerobic) may cause spoilage in certain meat products pasteurized in hermetically sealed containers if these are stored with inadequate refrigeration. After having optimized a method for determination of the redox potential in sausage mixtures, we investigated the contribution of low redox potential (E_h) and anaerobiosis to the inhibition of these bacili. With the E_h values encountered in pasteurized meat products there was no effect of the redox potential on growth of B. licheniformis, either in model broths or in mildly heated bologna-type sausage mixtures. When cultured in a model broth with head space, B. subtilis grew to about 10⁷/ml and was little affected by the initial E_h value (range between + 250 and − 150 mV) and the initial dissolved oxygen concentration. During exponential growth of this bacterium in the absence of oxygen, the E_h value increased by about 180 mV. In sausage mixture with air inclusions, B. subtilis attained slightly higher cell densities than in mixtures protected against air uptake but it was subsequently overgrown by facultative anaerobic bacilli. We conclude that knowledge of the E_h value of a meat product does not permit a prediction of the growth potential of bacilli in pasteurized meat products, and that a sufficient heat treatment and proper refrigeration are essential to control these bacteria.     

A review of modified atmosphere packaging of fish and fishery products – significance of microbial growth, activities and safety

Modified atmosphere packaging (MAP) extends shelf-life of most fishery products by inhibiting bacterial growth and oxidative reactions. The achievable extension of shelf-life depends on species, fat content, initial microbial population, gas mixture, the ratio of gas volume to product volume, and most importantly, storage temperature. The shelf-life of fishery products is usually limited by microbial activity, although for some fatty fishes or at superchilled storage, it can be limited by nonmicrobial activity. Packaging of fishery products under modified atmospheres (MA) increases shelf-life compared with those packaged under air, but confers little or no additional shelf-life increase compared with vacuum packaging. The specific spoilage organism (SSO) of MA packaged cod at 0 °C has been found to be Photobacterium phosphoreum . Whether or not this bacterium is the general SSO for all marine temperate fishes at different storage temperatures and under various CO₂/N₂/O₂ mixtures needs to be resolved. Without proper control of storage temperature, the benefits of MAP may be lost. Higher temperatures inevitably lead to less dissolved CO₂ in the product and consequently loss of inhibitory effect, which may result in higher microbial and enzymatic activity, and uncertainties concerning the microbial safety, as food-borne pathogens might be present in the product.     

Irradiation of pre-packaged sliced cooked meat products with low and normal sodium content

Irradiation experiments were carried out with pre-packaged sliced cooked meat products with different initial counts of Enterobacteriaceae and mesophilic aerobic bacteria. In low-sodium meat products Enterobacteriaceae could effectively be inactivated in refrigerated or frozen products by irradiation with a dose of 1 or 2 kGy respectively, provided the number of these bacteria was below 10(3) to 10(4) per g. The low-sodium meat products involved endured above treatment without being seriously affected as to sensory qualities. Shelf-life of salted cooked meat products could be prolonged by irradiating the frozen product. Irradiation with a dose of 2 kGy enabled uncooled storage of the product for a restricted period (5-7 days). Best results were obtained for meat products with a salt content in the brine phase of greater than 4.0% (w/w) and having a good hygienic quality, i.e. an initial bacterial count below 10(4)/g. Packaging in a gas atmosphere (CO2) slightly enhanced protection as compared to vacuum packaging. Off-flavours as a result of irradiation of salted cooked meat products varied from slight to strong and depended on the type of product.     

熏煮香肠保水性评价模型研究

为了构建熏煮香肠保水性(water-holding capacity,WHC)评价模型,本研究以添加不同胶体辅料的熏煮猪肉香肠的硬度、弹性、内聚性、咀嚼性、WHC、保油性(fat-holding rate,FHR)等品质指标为研究对象,采用主成分分析、聚类分析等多元分析方法,研究了熏煮香肠品质指标间的关系,构建了保水性...     

Characteristics of carbon dioxide sorption by stored wheat

The sorption of carbon dioxide gas (CO₂) by wheat was determined in glass flasks at four temperatures (0, 10, 20 and 30 °C) and four moisture contents (m.c.) (12, 14, 16 and 18% wet basis). The gaseous concentrations were analyzed by gas chromatography and the vacuum developed from the sorption of CO₂ by wheat was measured with a mercury manometer. The calculated amount of CO₂ sorted at equilibrium was a non-linear function of both temperature and moisture content. Sorption of CO₂ by wheat decreased with increasing temperature from 0 to 30 °C at 14% m.c., and the initial rate of sorption increased with increasing m.c. from 12 to 18% at a temperature of 20 °C. Sorption was modelled using non-linear regression at two conditions (0–30 °C at 14% moisture content and 12–18% moisture content at 20 °C). The maximum mass of CO₂ sorbed in 60 h was 0.510 g/kg of wheat at 18% m.c. and 0 °C and the lowest was 0.224 g/kg at 18% m.c. and 30 °C. A linear relationship existed between the initial CO₂ concentration and the concentration after 60 h when 250 g of wheat of 14% m.c. at 20 °C was exposed in 500 ml flasks.     

分散染料在超临界二氧化碳流体中的溶解性

为更好地筛选适用于超临界二氧化碳(ScCO2)流体染色的分散染料,使用状态方程结合基团贡献法和计算化学法,得到不同工况条件及不同染料结构对分散染料在超临界CO2流体中溶解度的影响规律,建立了分散染料在超临界CO2流体中溶解度预测方法.结果表明:不同工况条件会影响分散蓝79染料的溶解度,其中较低的温度和较高的压力对溶解过...     

Photooxidation of nitrosylmyoglobin at low oxygen pressure. Quantum yields and reaction stoechiometries

Photooxidation of the nitrite-cured meat pigment, nitrosylmyoglobin, in aqueous solution saturated with a 20% CO₂/80% N₂ gas mixture with varying oxygen contents (0.1, 0.5 or 1.0%) was found to depend linearly on the oxygen content for both visible (436 nm) and UV-light (366 nm). Quantum yields were similar for the two wavelengths of excitation in agreement with previous findings at higher oxygen pressures. The reaction stoechiometry for photooxidation was different from that of thermal oxidation (investigated at the same oxygen pressures) with a unity MbFe(II)NO/O₂ ratio in the thermal reaction and a ratio larger than one for the photooxidation. For cured meat products packed in modified atmospheres light exposure may be even more harmful for the oxidative stability than expected from the concentration of residual oxygen.     

推动肉制品发展的加工机械

<正> 肉制品在国际市场的需求甚高,特别是一些经济发达并注重环保卫生的国家和地区。目前,国际上进口肉类最多的国家和地区依次为:日本、俄罗斯、香港特别行政区、台湾省、韩国。欧美国家自英、法等国近年来先后爆发疯牛病、口蹄疫后,更渴求大量的进口牛、猪肉,这对中国来说是进入欧美市场的大好时机。 要开拓出口肉类市场,先进的加工机械不可或缺。然而,在中国人民消费的食品中,大多是农业的自然食品,其加     

Incidence of Listeria monocytogenes in different types of meat products on the Belgian retail market

A survey was undertaken to determine the incidence and numbers of L. monocytogenes in a variety of meat products (cooked meat products, raw cured meat products (dried or not), mayonnaise based salads and prepared meals). As expected, raw cured meat products were significantly higher contaminated with L. monocytogenes than cooked meat products, 13.71% (113/824) and 4.90% (167/3405), respectively. Also a larger proportion of raw cured meat product samples contained a high initial level of the pathogen ( > 10 cfu/g). Higher incidence rates were obtained for whole cooked meat products (e.g. cooked ham, bacon) after slicing than before slicing, 6.65 and 1.56%, respectively, indicating cross-contamination. Due to multiple handling and processing steps, the incidence rate of the pathogen was higher for cooked minced meat products than for whole cooked meat products, 6.14 and 3.96%, respectively. No significant differences were obtained in the incidence of L. monocytogenes in whole cured meat products (e.g., raw ham) and minced cured meat products (e.g., dry fermented sausage), 14.92 and 11.69%, respectively. Lower incidence rates of L. monocytogenes were obtained for raw, cured meat products using beef or horse meat, 4.65 and 5.88%, respectively, A high incidence rate of L. monocytogenes was noted for the mayonnaise based salads (21.28% (186/874)) as well as for prepared meals (11.70% (92/786)), the latter especially due to contamination of vegetarian meals.     

分散紫27与分散蓝72在超临界CO2中溶解度的测定

在温度343.15~383.15 K、压力14~22 MPa条件下,采用动态法测定分散紫27、分散蓝72在超临界CO₂中的溶解度。并采用Chrastil半经验模型和AdMST半经验方程对实验结果进行关联,探讨影响分散染料在超临界CO2中溶解度的因素。结果表明:分散紫27在超临界CO₂中的溶解度为2.69×10^-6~7.35×10^-6 mol/mol,压力越高,CO₂密度越大,分散紫27在超临界CO₂中的溶解度越高;随着温度的升高,分散紫27的溶解度先升高后降低;分散蓝72在超临界CO₂中的溶解度为7.17×10^-6~13.38×10^-6 mol/mol,且随着温度的升高而升高,随着压力的升高而升高。     

The Sensory Quality of Meat,Game, Poultry,Seafood and Meat Products as Affected by Intense Light Pulses: A Systematic Review

The effect of intense light pulses (ILP) on sensory quality of 16 different varieties of meat, meat products, game, poultry and seafood are reviewed. Changes induced by ILP are animal species, type of meat product and fluences applied dependent. ILP significantly deteriorates sensory quality of cooked meat products. It causes less change in the sensory properties of dry cured than cooked meat products while fermented sausage is least affected. The higher fluence applied significantly changes the instrumental color values of meat, poultry, game and meat products. The use of ILP on seafood regarding its influence on sensory quality is promising.