不同贮藏方式对高压鸡汤品质的影响及货架期预测模型的建立

研究冷藏、微冻和冻藏3 种贮藏方式对高压鸡汤感官品质、pH值、L*（亮度）、b*（黄度）、Y总（浊度）、总挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、硫代巴比妥酸反应物（thiobarbituric acid-reactivesubstance,TBARS）值以及菌落总数（total viable count,TVC）的影响,并建立了高压鸡汤货架期预测动力学模型。结果表明：随着贮藏时间的延长,冷藏、微冻和冻藏鸡汤的感官评分、pH值均呈现逐渐下降趋势,而TVB-N值、TBARS值和TVC的变化趋势则与之相反。其中冷藏因贮藏温度较高较另两种方式变化显著（P＜0.05）。此外,鸡汤的L*、b*和Y总在贮藏期间没有呈现一定的规律性变化。结合一级化学反应动力学方程和Arrhenius方程建立了高压鸡汤TBARS贮藏动力学预测模型,验证结果显示,利用此模型得到的鸡汤货架寿命预测值与实际值相对误差低于10%,说明模型可靠,在此基础上得出－2.5 ℃和－18 ℃贮藏温度条件下高压鸡汤的货架期预测值分别为136 d和258 d,较4 ℃冷藏分别延长了55 d和177 d,可为营养汤品的安全贮藏提供一定的理论指导。与其他2 种方式相比,微冻保藏产品品质好,货架期长,成本低,可能会成为营养汤品未来工业化生产贮存和超市销售存放的较佳途径。     

Antioxidant and Antimicrobial Activity of Commercial Propolis Extract in Beef Patties

The objective of this study was to evaluate the efficacy of propolis extract (PE) to reduce lipid oxidation and microbial growth on beef patties during refrigerated storage. Beef patties were manufactured by incorporating PE in 4 different treatments: (1) Control (no PE addition); (2) commercial propolis 1 (2% w/w; CP1); (3) commercial propolis 2 (2% w/w; CP2); and (4) noncommercial propolis (2% w/w; NCP). Raw patties were wrapped with polyvinyl chloride and stored at 2 °C for 8 d. Total phenolic content (TPC), free‐radical scavenging activity (FRS), and polyphenolic content of the PE were evaluated using high‐performance liquid chromatography (HPLC). Lipid oxidation (thiobarbituric acid‐reactive substances (TBARS), conjugated dienes (CnDs), metmyoglobin (MetMb%), pH variation, and color (L*, a*, b*, C*, and h*), and microbial growth (mesophilic and psychrotrophic bacteria) of patty samples were measured. NCP treatment demonstrated the highest FRS (64.8% at 100 μg/mL), which correlated with TPC and the presence of polyphenolic compounds. Lipid oxidation (78.54%, TBARS; 45.53%, CnD; 58.57%, MetMb) and microbial mesophilic and psychrotrophic growth (19.75 and 27.03%, respectively) values were reduced by NCP treatment in refrigerated samples after 8 d. These results indicate that PE has great potential as a natural antioxidant and antimicrobial additive to extend the shelf life of beef patties.     

Evaluation of the storage life of vacuum packaged Australian beef

To establish the shelf-life of vacuum packaged Australian beef, 15 Strip-loins and 15 Cube-rolls for each Processor (A, B, and C) were evaluated at two week intervals (since wk 10 to 20). Steaks on the trays were placed in retail cabinets at 3 °C. Shelf-life evaluation was based on off-odor (only at week 10), microbial analysis, lipid oxidation, and color assessment by trained panelist and Hunter colorimeter. Panelists detected "slightly off-odor" in both primal cuts for Processors B and C (P<0.05). Processor A primal cut steaks displayed better color scores as well as CIE L*, a*, b*, Chroma and Hue values during storage and display period than steaks from the other processors. Also, primal cuts from Processor A showed lower microbial counts and TBARS values with respect to other processors during the trial. Processor A cuts showed improved shelf life attributes initially which helps to explain its slow shelf-life deterioration.     

Effect of modified atmosphere and vacuum packaging on some quality characteristics and the shelf-life of “morcilla”, a typical cooked blood sausage

The effect of modified atmosphere and vacuum packaging on the shelf-life of “morcilla”, a traditional cooked blood sausage, was investigated. A total of 99 “morcillas” were packaged under vacuum and in modified atmosphere using three different gas mixtures: 15:35:50/O₂:N₂:CO₂ (atmosphere 1), 60:40/N₂:CO₂ (atmosphere 2) and 40:60/N₂:CO₂ (atmosphere 3), and stored during 2, 4, 6 and 8 weeks at 4 °C. Shelf life evaluation was based on pH, water activity (a_w), colour (CIE L*, a*, b*, C* and h*), TBARS formation and microbial counts. The results indicated that, in general, storage time affected (P < 0.05) all parameters whereas no significant differences were observed (P > 0.05) among packaging conditions. Based on the microbial counts, the shelf-life of “morcilla” would be greater than 8 weeks for all packaging conditions. Samples packaged with high CO₂ concentrations (40:60/N₂:CO₂) showed the lowest values of TBARS at the end of storage.     

Pork liver protein hydrolysates as extenders of pork patties shelf-life

The growing demand for the consumption of more natural products challenges the food industry to meet consumer expectations. In this regard, bioactive peptides obtained from flavourzyme, bromelain and alcalase activity were added to pork patties with the aim of improving their shelf-life. Five treatments were prepared: control (CON, without enzymatic extract), positive control (ASA, with 150 mg kg⁻¹ of ascorbic acid) and three batches with 250 mg kg⁻¹ of different porcine liver hydrolysates [flavourzyme (FLA), bromelain (BRO) and alcalase (ALC)]. The analysis of raw burgers included proximate composition (moisture, protein, fat and ash contents), colour parameters (L*, a*, b*), metmyoglobin, lipid oxidation, volatile compounds profile and sensory evaluation. Hydrolysate obtained from bromelain enzyme showed the best a* parameter (5.15), the least lipid oxidation (0.63 mg MDA kg⁻¹) and the lowest percentage of metmyoglobin (56.02%). Furthermore, this batch also presented the lowest content of aldehydes and alcohols resulting from lipid oxidation. Our results suggested that the hydrolysates obtained from bromelain activity possessed a good antioxidative activity, and therefore, they could be used as a natural antioxidant to extend the shelf-life of pork burgers.     

Effect of different concentrations of carbon dioxide and low concentration of carbon monoxide on the shelf-life of fresh pork sausages packaged in modified atmosphere

This paper reports the effects of different concentrations of carbon dioxide and the presence of low levels of carbon monoxide on quality attributes throughout storage of fresh pork sausages. Four pork forelegs (initial pH 5.5-5.7) were used to prepare a total of 120 fresh sausages, which were packaged in different atmospheres containing (%O(2)/%CO(2)/%N(2)): 0/20/80; 0/60/40; 40/20/40; 40/60/0; 80/20/0; and 0.3% CO/30% CO(2)/rest argon. The packs were stored for 20 days at 2±1 °C in the dark. Three packs for each atmosphere were opened every 4 days for subsequent analysis of pH, colour CIE L*, a*, b*, TBARS formation, microbial psychotrophic aerobes and sensory discolouration and off-odour. Results showed that increasing concentrations of carbon dioxide promoted oxidation of both myoglobin and lipids, most probably due to its effect of lowering pH. Therefore, preservation of colour and odour of fresh pork sausages packaged in modified atmosphere was better achieved using atmospheres containing low CO(2) concentrations (20%) rather than high (60%). However, their shelf-life depended also on the concentration of O(2); 20% CO(2) with high O(2) (80%) enhanced the red colour, but shortened shelf-life, while 20% CO(2) in the absence of O(2) extended freshness to 16 days. The atmosphere containing 0.3% CO, together with 30% CO(2), maintained the red colour for 20 days, but failed to keep fresh odour longer than 16 days.     

Evaluation of physicochemical properties and microbial counts of raw and cooked low-fat patties added with eggplant powder prepared with different drying methods

Effects of different drying methods and different addition levels of eggplant (EP) on product quality of low-fat patties (LFPs) were investigated during storage. EP was dried in an oven dryer at 60 °C or a freeze dryer at −50 °C. LFPs were prepared by replacing with 1.5% soy protein isolate (SPI). Six treatments were used in this study: (1) control (CTL), without addition of EP; (2) reference (REF), 0.1% ascorbic acid; (3) O1, 0.25% oven-dried (OD) EP; (4) O2, 0.5% ODEP; (5) F1, 0.25% freeze-dried (FD) EP; and (6) F2, 0.5% FDEP. Redness (a*) and lightness (L*) values in LFPs added with EP were lower than those of others (p < 0.05) and decreased with increasing storage time. Yellowness (b*) values of cooked patties were increased during storage time (p < 0.05), with control having the highest value. The addition of EP or ascorbic acid into LFPs lowered microbial counts than control (p < 0.05). Thiobarbituric acid reactive substances (TBARS) was increased during storage, with REF having the lowest value, and patties added with EP had lower TBARS values than control during storage. Volatile basic nitrogen (VBN, mg%) contents of all patties also increased during storage time with O2 and F2 having lower values than control. Therefore, EP might have potential as a natural antioxidant in meat products during storage.     

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.     

The effects of ascorbic acid, taurine, carnosine and rosemary powder on colour and lipid stability of beef patties packaged in modified atmosphere

This research was aimed at evaluating the inhibition of oxidative changes of beef patties packaged in modified atmosphere (70% O₂+20% CO₂+10% N₂) by natural antioxidants: ascorbic acid (500 ppm), taurine (50 mM), carnosine (50 mM), rosemary powder (1000 ppm) and their combinations with the first. Beef patties stored at 2±1°C for 20 days were evaluated for colour (L*, a*, b*, C* and H*), TBARS, metmyoglobin formation (% of total myoglobin), psychrotrophic microbial counts and sensory odour and discolouration. Rosemary, either alone or with ascorbic acid, was highly effective in inhibiting both metmyoglobin formation and lipid oxidation; sensory analysis was in agreement with these results. Ascorbic acid, ascorbic acid+taurine and ascorbic acid+carnosine treatments showed a limited inhibitory effect of myoglobin oxidation, while carnosine and carnosine+ascorbic acid were effective in inhibiting lipid oxidation. Taurine alone failed to exert any antioxidant effect. Principal components analysis confirmed these results.     

Effects of ionizing radiation on sensorial, chemical, and microbiological quality of frozen corn and peas

The effects of irradiation (0, 1.8, and 4.5 kGy) on the quality of frozen corn and peas were investigated during a 12month period of postirradiation storage at -18 degrees C. Irradiation of frozen corn and peas caused a reduction in ascorbic acid content of both vegetables and a loss of texture in peas but had no significant effects on instrumental color parameters (L*, a*, and b*), carotenoid and chlorophyll content, or antioxidant capacity of corn and peas. Irradiation reduced microbial loads of frozen peas and increased display life at 23 degrees C of thawed peas by preserving the green color, apparently because of slower increases in the population of acid-producing microorganisms in the irradiated samples. Overall, irradiation significantly reduced the microbial load and increased the display life of peas and had minimal detrimental effects on the quality of frozen corn and peas.     

Conjugated Linoleic Acid Reduces Lipid Oxidation in Aerobically Stored, Cooked Ground Beef Patties

ABSTRACT: The effect of direct addition of conjugated linoleic acid (CLA) on lipid oxidation was studied. CLA and/or fat trim (4% by weight) were added to the lean trim (96%). Thiobarbituric acid reactive substances (TBARS) were determined on days 0, 3, and 7 for cooked or raw patties stored aerobically at 4 °C. Addition of CLA during the grinding process increased CLA isomers in both raw and cooked ground beef and decreased TBARS production ( P < 0.01). CLA caused a greater reduction in TBARS over storage time in cooked patties than in raw patties ( P= 0.006). The concentrations of 18:2n–6 and CLA isomers decreased with storage time. CLA increased 18:2n-6, whereas most fatty acids were decreased by the addition of CLA. CLA did not affect percentages of fat and moisture, cooking loss, or meat color (L*, a *, b *) ( P > 0.60).     

真空包装对哈尔滨红肠品质的影响

研究真空包装对哈尔滨红肠品质的影响,将真空包装和普通袋装哈尔滨红肠置于（4±0.5）℃条件下进行贮藏,分析pH值、水分活度（aw）、色泽、硫代巴比妥酸（thiobarbituric acid reactive substance assay,TBARS）值、总挥发性盐基氮（total volatile basic nitrogen,T-VBN）值、菌落总数和感官品质变化。结果显示贮藏时间和包装形式对aw影响差异不显著（P＞0.05）,但pH值和感官评分均随贮藏时间延长显著下降（P＜0.05）,真空包装的TBARS值、T-VBN值和菌落总数在贮藏过程中均显著上升（P＜0.05）,并且普通袋装的pH值和感官评分下降速率显著高于真空包装（P＜0.05）,真空包装的TBARS值、T-VBN值和菌落总数的增长显著低于普通袋装样品（P＜0.05）。普通袋装样品的色泽在整个贮藏过程中变化显著（P＜0.05）,其中L*值显著下降,a*值和b*值显著上升,但是真空包装样品色泽变化差异不显著（P＞0.05）,并且在贮藏过程中真空包装样品的L*值显著高于普通袋装样品,a*值和b*值则显著低于普通袋装样品（P＜0.05）。各个指标之间的相关性研究结果显示菌落总数、pH值、TBARS值、T-VBN值和感官评分呈现强相关性（P＜0.05）,其中感官评分和各个指标的相关性最强。研究结果表明,真空包装比普通袋包装能够有效地减缓样品理化指标、微生物指标和感官品质的变化,能够有效延长哈尔滨红肠的货架期;并且通过研究包装形式对感官品质的影响,可以快速有效地推出包装形式对哈尔滨红肠微生物和理化指标的影响。     

Effect of Maillard reaction products on oxidation products in ground chicken breast

Three amino acid-sugar solutions were adjusted to pH 8.0, heated and lyophilized prior to addition to ground chicken breast (GCB). GCB with no additives, GCB with 0.01% BHT, GCB with 0.1 or 0.2 mg/g glucose heated with arginine, valine, or histidine were prepared. Thiobarbituric acid reactive substances (TBARS), volatiles determined by gas chromatography, and Hunter L*, a* and b* values were monitored over nine days. Multiple linear regression models were used to determine the effects of the studied factors on the corresponding outcome variables. a* values of GCB ranged from 1.60 to 4.90 over nine days of storage. While Maillard reaction products (MRP) lowered oxidation compared to control, no significant difference in TBARS between MRP solutions heated for 8 or 24 h was found. Further, 0.1 mg/g heated glucose-valine mixture decreased aldehydes up to 72.87%. Therefore, shelf-life of GCB could be extended using 0.1 or 0.2 mg/g MRP.     

Effects of Carbon Monoxide Packaging on Color and Lipid Stability of Irradiated Ground Beef

ABSTRACT: The effects of packaging atmosphere (aerobic, vacuum, or modified atmosphere with carbon monoxide) on ground beef treated with ionizing radiation were investigated. Measurements of color (CIE L*, a*, b*), lipid oxidation (TBA value), and sensory quality were conducted during 28 d of storage at refrigerated (0 to 2°C) temperatures. Irradiation significantly ( p > 0.001) decreased color scores and increased TBA and off-odor scores. The MAP + CO treatments increased the L* and a* values ( p < 0.001), regardless of irradiation dose. The TBA values for MAP + CO-packaged samples were well below the levels considered "rancid" (about 1.0). In addition, sensory scores indicated minimal production of irradiation off-odors with MAP + CO packaging.     

Characterization of traditional Istrian dry-cured ham by means of physical and chemical analyses and volatile compounds

The aroma-active compounds of Istrian dry-cured ham were investigated by using headspace-solid phase microextraction and gas chromatography-mass spectrometry (GC-MS). Samples of biceps femoris were also evaluated by measuring physical and chemical characteristics: moisture, protein, fat, ash and NaCl content, a(w) value; colour: L*, a*, b* and oxidation of fat: TBARS test. About 50 volatile compounds were identified and quantified which belonged to several classes of chemical: 5 alcohols, 8 aldehydes, 7 alkanes, 1 ketone, 2 esters, 9 monoterpenes and 15 sesquiterpenes. Except volatile compounds derived from lipolysis and proteolysis the most abundant constituents were terpenes (62.97; 41.43%) that originate from spices added in the salting phase of the production process.     

Discoloration Characteristics of 3 Major Muscles From Cattle During Cold Storage

ABSTRACT:  Discoloration characteristics of 3 major muscles (LD, Longissimus dorsi; PM , Psoas major; SM, Semimemebranosus ) from Korean native cattle (Hanwoo) were monitored during 7 d of cold storage at 4 °C. The muscles were obtained from 12 Hanwoo carcasses at 24 h postmortem. Meat color (CIE L *, a *, b *), myoglobin (Mb) concentration, chemical form, metmyoglobin (MetMb) reducing ability (MRA), mitochondria concentration, and thiobarbituric acid reactive substance (TBARS) were measured at 1, 3, 5, and 7 d of storage. Although there were no significant differences in CIE a * and b *-values between the 3 muscles at day 1, the values of PM muscle were significantly ( P < 0.05) lower than those of LD and SM muscles at day 5 and 7. PM muscle showed a rapid decrease in the oxymyoglobin (OxyMb) and an increase in MetMb, which resulted in a significantly ( P < 0.05) higher percentage of MetMb in PM muscle compared to LD and SM muscles. Also, the Mb and mitochondria concentration of PM muscle was significantly ( P < 0.05) higher than those of LD and SM muscles. However, there were no significant differences in MRA, pH, or TBARS between the 3 muscles during 7 d of cold storage. It was concluded that rapid discoloration (that is, MetMb accumulation) in PM muscle of Hanwoo could be due to its higher contents of Mb and mitochondria.     

Carcass and meat quality in light lambs from different fat classes in the EU carcass classification system

Ninety commercial lamb carcasses were analysed according to the four different fat classes in the light lamb European classification system. Shoulder fat increased 3%, muscle decreased 2% and bone decreased 1% for each class increase. No significant differences were found among fat classes regarding pH, WHC, cooking losses, juiciness, myoglobin content, meat colour measured immediately after cutting (L*, a*, b*), odour intensity or flavour quality. Some differences were found in colour evolution through ageing. Shear force decreased and tenderness and flavour intensity increased with fat class but this effect was only significant in the leanest animals.     

槲皮素和NaCl添加量对牦牛肉饼蛋白质和脂质氧化的影响

为研究槲皮素（Quercetin,Q）和不同NaCl添加量（0%、2%、4%、6%,m/m）对牦牛肉饼在贮藏过程中蛋白质和脂质氧化的影响,测定了牦牛肉饼在冷藏15 d期间的pH值、色差、羰基含量、表面疏水性、色氨酸荧光强度、二聚酪氨酸含量、过氧化值（Peroxide Value,POV）和硫代巴比妥酸反应物（Thiobarbituric Acid Reactive Substances,TBARS）值。结果表明,随着NaCl添加量增加,pH值增加（P<0.05）,L*、a*和b*值先增加后降低（P<0.05）;添加槲皮素后咸肉饼的pH值（P<0.05）、a*和b*值增加（P<0.05）、L*值降低（P<0.05）。添加NaCl使肉饼的羰基、表面疏水性、二聚酪氨酸、POV值和TBARS值增加（P<0.05）,色氨酸荧光强度减小（P<0.05）;但槲皮素处理使咸肉饼的色氨酸荧光强度、二聚酪氨酸、POV值及TBARS值降低,使4% NaCl（质量分数）肉饼的羰基含量降低了27.80%;表面疏水性在0~2% NaCl（质量分数）添加量下进一步增加（P<0.05）,而在4%~6% NaCl添加量下降低（P<0.05）。该研究表明,NaCl能促进牦牛肉饼蛋白质和脂质氧化,但加入槲皮素可有效缓解肉饼氧化。该结果可为槲皮素作为肉制品天然抗氧化剂提供参考。     

Meat Color and Biochemical Characteristics of Unacceptable Dark-colored Broiler Chicken Carcasses

Spectrocolorimetry, pH, TBARS, total pigment and myoglobin were measured in normal and abnormally dark-colored broiler chicken breast muscle. Analyses of L*, a* and b* values revealed that a* values were highly sensitive and specific to differentiate normal from dark-colored carcasses and thus could be used as a potential diagnostic method for carcass classification at slaughter. Color characteristics (L*, a*, and b* values), pH, total pigment, myoglobin, and iron concentrations were all significantly different in dark-colored muscle when compared with normal muscle. TBARS values and percentage moisture for the two groups were not different.     

Genetic parameters of carcass and meat quality traits of double muscled Piemontese cattle

Genetic parameters of meat quality (MQ) were estimated on Longissimus thoracis muscle of 1208 Piemontese young bulls, progeny of 109 AI sires. Carcass weight (CW), conformation (EUS) and pH (pH24h) were recorded at 24h and lightness (L*), redness (a*), yellowness (b*), pH (pH8d), drip loss (DL), cooking loss (CL) and shear force (SF) were assessed. The heritability (h(2)) of pH24h was very low (0.06), but h2 of pH8d was markedly higher (0.42). Heritability was 0.32, 0.33, and, 0.14, for L*, a* and b*, respectively, whereas was 0.24, 0.07 and 0.14, for DL, CL, and SF, respectively. The two pH measures showed opposite genetic relationships with color measures. Genetic correlations of DL and CL were positive with L* and b* and negative with a*. Genetic correlations between carcass traits and MQ suggest that animals with superior growth potential tend to exhibit reduced EUS scores and pale meat with lower tenderness and water holding capacity. Conversely, improvement of EUS score through selection would lead to light, bright, and tender meat with enhanced water holding capacity.