冰温结合气调贮藏对新鲜牛肉的保鲜研究

研究了冰点调节剂食盐和蔗糖对新鲜牛肉冰点的影响;通过研究新鲜牛肉贮藏过程中色差值、菌落总数、pH值、挥发性盐基氮、液汁流失率等指标的变化情况,分析比较了冰温条件下4种气调包装与真空包装、空气包装对牛肉品质的影响。结果显示,当用食盐(添加量为1%)、蔗糖(添加量为0.6%)对牛肉进行调味时,冰温带由0～-0.76℃拓宽至0～-4.56℃,更有利于冰温贮藏温度的控制;冰温气调对新鲜牛肉的保鲜作用明显,第12天时C组样品色泽保持较好,TVB.N为6.68 mg/(100g),菌落总数为3.97 log cfu/g,在国家一级鲜肉标准范围内;第32天时,TVB.N为14.36 mg/(100g),菌落总数为5.38 log cfu/g,未超过相关限量规定,而真空组和空气组均已腐败,说明冰温与气调包装结合可起到协同保鲜作用,更有利于延长新鲜牛肉的货架期。     

气调包装协同天然保鲜剂对冷却牛肉的保鲜研究

研究了气调包装与复合天然保鲜剂联合使用对冷却牛肉保鲜的效果。将复合保鲜剂与高氧浓度的各种气调包装协同使用,并且在(4±1)℃条件下贮藏,以真空包装为对照,对牛肉菌落总数、pH值、挥发性盐基氮、液汁流失率、嫩度、弹性、色泽等指标进行检测分析,确定了延长牛肉货架期的较佳条件为:气调包装气体体积分数为70%O2/20%CO2/10%N2,复合保鲜剂为质量分数1%壳聚糖/0.2%茶多酚。     

精准冰温对鲜牛肉贮藏品质的影响

在-2.5℃的冰温和0℃、4℃三种温度条件下贮藏排酸后的鲜牛肉,定期测定牛肉出汁率、TPA指标、色泽、p H、挥发性盐基氮(TVB-N)、微生物菌落总数等品质指标,为鲜牛肉的精准冰温保鲜提供参考。结果表明:冰温库库温稳定,在4℃、0℃和-2.5℃条件下贮藏的牛肉,有效保鲜期分别为8 d、15 d和24 d。在-2.5℃条件下贮藏24 d时,鲜牛肉p H值为5.59,TVBN含量为15.39 mg/100 g,微生物菌落总数为2.2×106CFU/g,色泽鲜红,无腐败异味出现。与4℃和0℃相比,-2.5℃冰温能够有效保持牛肉的颜色,减少出汁率,减缓p H值和TVB-N含量增大,抑制微生物的生长繁殖,有效延长生鲜牛肉的贮藏保鲜时间。     

低温冻藏过程中鲐鱼肌肉蛋白质氧化特性研究

目的 探讨低温冻藏过程中鲐鱼肌肉蛋白质的氧化规律。方法 以鲐鱼为研究对象,在-18 ℃条件下分别贮藏10,20,40,60,80,100 d,测定鲐鱼的pH值、色泽、肌肉质构特性,提取肌原纤维蛋白,测定羰基含量、巯基含量、表面疏水性。结果 随着冻藏时间的增加,鲐鱼的pH值呈现先下降后上升的趋势;在色差测定中,鲐鱼的L*值不断降低,a*值也呈下降趋势;鲐鱼的硬度、弹性、胶粘性和咀嚼性均呈下降趋势,且贮藏时间越长,下降程度越明显;鲐鱼的蛋白表面疏水性随着贮藏时间的延长,呈上升趋势;肌原纤维蛋白羰基含量随着贮藏时间的增加而增多,巯基含量却出现相反现象,随着贮藏时间的增加而减少。结论 鲐鱼在低温冷冻贮存前期,肌肉蛋白质小幅度降解,品质逐渐发生劣变,随着冻藏时间的增加,在贮存后期其蛋白质品质会出现大幅度下降。     

真空包装大米贮藏品质影响因素的研究

探讨了不同真空度、环境条件和贮藏时间对大米贮藏品质的影响。选用了市售天津小站大米为研究对象,选定不同真空度对其进行了真空包装,在不同环境条件下进行了模拟贮藏,定期测定了样品中的脂肪酸值、水分和还原糖含量,采用正交设计方法对测定结果进行了分析,确定了影响真空包装大米贮藏品质的主要因素。结果表明,在短期内,真空度是影响大米贮藏品质的最主要因素。     

不同包装方式对黑山羊冷鲜肉保鲜效果的比较

目的以新鲜的黑山羊肉为原料,研究真空和气调包装对山羊肉贮藏过程中感官质量、pH值、色泽、菌落总数、TVB-N值等主要技术指标变化的影响。方法将山羊屠宰后取其后腿,在-18℃下冷却到中心温度低于4℃后,去掉筋腱和脂肪,切分成约30 g的肉块,随机分成2组,装入已灭菌的包装袋内进行真空和气调包装,4℃贮藏,每隔3 d进行技术指标的测定。结果贮藏到16 d时,气调包装组的感官品质明显优于真空包装组;整个贮藏期,2组试样的pH值都低于6.6,即符合标准中对山羊肉pH值的要求;贮藏的前16 d,气调包装组的a*值高于真空包装组,表明气调包装较好地保持了羊肉的自然色泽;贮藏到16 d时,真空包装组的菌落总数为6.12,已超标,而气调包装组的试样属于次鲜肉;贮藏20 d,气调包装组的TVB-N值仍不超标,而真空包装组的TVB-N值为21.48,已超标。结论采用气调包装比真空包装好,能使山羊肉贮藏16~20 d。     

复合壳聚糖保鲜液膜对冷鲜牛肉保鲜的研究

目的通过涂膜对牛肉进行保鲜,将质量浓度为10 g/L的4种天然植物精油(迷迭香精油、葡萄籽油、茴香籽精油及柠檬精油)添加到壳聚糖与玉米醇溶蛋白的复合涂膜保鲜液中,研究其在贮藏过程中对冷鲜牛肉的品质影响。方法通过测定牛肉的汁液流失率、p H值、TVB-N值、菌落总数和TBA值等指标,对牛肉品质进行综合评价来说明不同涂膜处理的保鲜效果。结果含质量浓度均为10 g/L的柠檬精油和葡萄籽精油的复合保鲜液对牛肉的保鲜效果最佳。结论使用包含柠檬精油和葡萄籽精油的质量浓度分别为10 g/L的复合保鲜液可对牛肉在温度为(4±1)℃的条件下保藏牛肉20 d以上。     

复合生物保鲜剂对冷鲜牛肉的保鲜效果研究

目的为了延长冷鲜牛肉的货架期,提高冷鲜牛肉贮藏期间的品质,研究复合生物保鲜剂的保鲜效果。方法利用多种生物保鲜剂对冷鲜牛肉进行处理,并在室温下进行贮藏,每隔3 d对冷鲜牛肉的含水量、pH和TVB-N值进行测定,并根据单因素实验所得结果,选择效果明显的保鲜剂按照一定比例组成复合生物保鲜剂,对冷鲜牛肉进行处理,并检验其保鲜效果。结果生物保鲜剂处理后的冷鲜牛肉的储存期和品质均较未处理的试样有明显提升,其中壳聚糖、茶多酚和溶菌酶的保鲜效果更明显,因此,选择这3种保鲜剂作为复合保鲜剂对冷鲜牛肉进行处理,在4℃条件下贮藏,并在第6天对其挥发性盐基氮进行了测定,分析结果表明,当壳聚糖、茶多酚和溶菌酶的质量分数分别为5%,1%,3%时,冷鲜牛肉的TVB-N取极小值59.2 mg/kg,仍然保持比较新鲜的状态。结论复合生物保鲜剂对冷鲜牛肉具有比较明显的保鲜作用,能够有效地延长肉品的货架期。     

不同电商物流终止温度对鮰鱼冻藏品质变化的影响

目的 研究不同电商物流终止温度下的鱼肉贮藏品质,从而推进农产品电商的发展。方法 将鮰鱼宰杀后进行真空包装,并快速将其冷冻,当中心温度稳定在-18 ℃后取出,进行电商物流模拟,待其到达不同电商物流终止温度（0,4,8 ℃）后,放入-18 ℃中冻藏5个月,每月测定其理化指标（pH值、色泽、汁液损失率、剪切力、三甲胺含量、硫代巴比妥酸（Thiobarbituric acid, TBA）含量、挥发性盐基氮（Total volatile base nitrogen, TVB-N）含量、新鲜度（K值））和蛋白质特性（盐溶性蛋白含量、巯基含量、羰基含量、表面疏水性）。结果 将鮰鱼冻藏5个月后,3组鮰鱼片的汁液损失率、剪切力、羰基含量、表面疏水性、三甲胺含量、TBA值、TVB-N值、K值均显著上升（P<0.05）,盐溶性蛋白含量、巯基含量显著下降（P<0.05）。在冻藏过程中,三甲胺含量、TBA、TVB-N、K值的增长速率为 v8 ℃＞v4 ℃＞v0 ℃。结论 电商物流终止温度分别为0,4,8 ℃的鮰鱼片在冻藏5个月后,持水性下降,肉质变硬,蛋白变性程度升高,新鲜度下降,加工品质大大降低,但均保持在二级鲜度以上,仍具有加工食用价值。此外,0 ℃的电商物流终止温度更有利于抑制鮰鱼片在冻藏过程中的品质劣变,4 ℃次之,8 ℃最差。     

陈列柜摆放位置对荔枝货架期品质的影响

目的研究不同销售方式及摆放位置对货架期荔枝果实品质变化的影响,为荔枝果实货架期保鲜和销售货架设计提供一定的参考。方法在敞开式陈列柜和常温货架上,以盒装的"怀枝"荔枝果实为实验材料,开展荔枝果实贮藏试验,研究货架期72h内荔枝果实分别放置在冷藏陈列柜不同位置和常温货架上品质的变化情况。结果在货架期内,冷藏陈列柜第4层和常温货架贮藏荔枝的果实褐变指数高于其他陈列位置,好果率低于其他陈列位置;冷藏陈列柜第4层的荔枝果实质量损失率的上升速率最快,72 h后上升至11.01%,其果皮色差a*值最小;第3层荔枝果实的质量损失率上升得最缓慢,其果皮色差a*值最大;常温货架荔枝的果皮色差L*值最大,其果肉的可溶性固形物含量和硬度最低;不同销售方式及摆放位置对荔枝果肉可滴定酸含量的变化影响不显著。结论在冷藏陈列柜中、上部摆放位置贮藏能相对更好地保证荔枝果实的销售品质,冷藏陈列柜的结构优化及其对温湿度场分布特性的影响将会是今后的研究方向。     

Shelf Life of Fresh Beef Stored in Master Packages with Carbon Monoxide and High Levels of Carbon Dioxide

Beef steaks from Gluteus medius, Longissimus dorsi, Psoas major and ground beef from Triceps brachii were packed in master packages containing expanded polystyrene trays overwrapped with polyvinyl chloride film under an anoxic atmosphere containing 0.2% CO, 60.0% CO₂ and 39.8% N₂ (T₁) or 0.2% CO/99.8% CO₂ plus oxygen scavengers. After 28 days of storage at 1 and 4°C, the meat quality was evaluated. The visual and instrumental colour of the beef steaks and ground beef were similar to that of fresh meat. Pathogenic bacteria were not detected, and psychrotrophic bacterial counts were lower than 7.5 log CFU/g. Copyright © 2012 John Wiley & Sons, Ltd.     

The properties of gelatin film‐neem extract and its effectiveness for preserving minced beef

The properties of gelatin films developed from neem extract (NE; Azadirachta indica) were determined. Moreover, the developed films were applied to minced beef to test its effectiveness for preserving the meat. The quality attributes of the minced beef wrapped with the developed film were monitored over a 7‐day period in refrigerated storage (4 ± 1°C) and were compared to a control commercial wrap film (polyvinyl chloride). The addition of NE improved the elongation at break, solubility, and antioxidant activity of the gelatin films. After 7 days of storage, the minced beef wrapped with the experimental film showed the highest a* and weight loss values. Gradually, changes in TBARS were more pronounced in the experimental sample. It was concluded that gelatin film containing NE is a potentially promising film that could help delay oxidative reactions. However, some characteristics of the film (eg, mechanical properties and water vapor permeability) need to be improved before putting them to commercial use.     

温度对自热食品理化指标影响及其货架期预测方法

目的以自热食品土豆牛肉菜肴包为研究对象,考察温度对其贮藏品质的影响,同时建立自热食品土豆牛肉菜肴包的货架期预测模型。方法利用加速货架期实验的方法,研究不同贮藏温度下(40,50,60℃)土豆牛肉菜肴包品质的变化,通过相关性分析选定货架期预测的代表性指标,基于理化指标变化运用化学动力学模型、Q10模型和BP神经网络模型建立自热食品的货架期预测模型,对其常温下货架期进行预测。结果在3种温度下,样品pH值基本呈现先下降再上升最后下降的趋势,且温度越高变化越剧烈;3种温度下,均有L*值先缓慢下降后急剧下降,a*值先是快速升高之后速率逐渐减慢,b*值则是相对较稳定的缓慢上升的趋势;脂质氧化和蛋白质水解的反应速率加快,致使丙二醛和挥发性盐基氮含量增加。相较于化学动力学模型和Q10模型,基于先验条件的BP神经网络模型最适用于该自热食品货架期预测,最终误差收敛于7.16×10^-5,用该模型预测25℃土豆牛肉菜肴包的货架期为430d。结论温度对土豆牛肉菜肴包各项品质指标均有显著影响,同时确立了货架期预测的最优模型为考虑先验条件的BP神经网络模型。     

洋葱提取物/PVA薄膜的制备及其对冷鲜肉品质影响的研究

目的制备复合保鲜膜,对冷鲜肉进行包装,评价其保鲜效果。方法通过测定膜的力学性能,并对贮藏期间冷鲜肉品的pH值、质量损失率、质构、挥发性盐基氮含量和菌落总数等保鲜性能指标进行检测,分析洋葱提取物/聚乙烯醇(PVA)膜对冷鲜肉品贮藏品质的影响。结果洋葱提取物/PVA复合保鲜薄膜具有良好的力学性能,当洋葱提取物添加量占PVA总量的0.056%时,抗拉强度为36.26MPa,断裂伸长率为59.72%。随着贮藏时间的增加,未添加洋葱提取物纯PVA薄膜中的肉品表面出现粘度增大、颜色变淡等现象;添加洋葱提取物的保鲜薄膜对肉品腐败有一定抑制作用,当洋葱提取物占PVA总量的0.069%时,保鲜效果最佳。结论洋葱提取物/PVA膜显著地保存了冷鲜肉品中的营养成分,延长了冷鲜肉品的贮藏时间,且对感官品质没有影响,达到了保鲜效果。     

Effects of active modified atmosphere on lipid and protein oxidation,moisture migration and quality properties of beef steaks

Fresh beef is a typically perishable food because of its high water and protein content; thus, it requires proper packaging condition and storage temperature to ensure its quality. In this study, the beef steaks were stored at 4°C under HiO₂ modified atmosphere packaging (MAP) (78.8% O₂ + 18.8% CO₂ + 2.4% N₂) and HiCO₂ MAP (60.0% CO₂ + 40.0% N₂). The traditional air packaging (AP) and vacuum packaging (VP) were used as the controls. The total viable count (TVC), colour, water holding capacity (WHC), myofibrillar protein (MP) oxidation and lipid oxidation of beef meat were investigated. The moisture distribution and migration were also analysed using the low-field nuclear magnetic resonance (LF-NMR). The association amongst all parameters was analysed by correlation analysis and principal component analysis (PCA). The results showed that the TVC values in the HiCO₂ MAP (5.6 log CFU/g) steaks were lower than those of VP (5.9 log CFU/g), AP (7.0 log CFU/g) and HiO₂ MAP (6.3 log CFU/g) steaks because of the sufficient CO₂ after 15 days of chilled storage. The bright red colour and the higher WHC were maintained in the HiO₂ MAP steaks than in the AP group during storage. However, higher levels of protein and lipid oxidation also occurred. The beef steaks stored under HiCO₂ MAP had the lowest protein and lipid oxidation and highest value of immobile water content and WHC, however, similar to the VP group, the bright red colour was not shown. The moisture attributes (drip loss, cooking loss and P₂₃), protein oxidation (protein solubility and carbonyl content) and lipid oxidation (TBARS value) have shown a close correlation by correlation analysis and PCA. Overall, two different packaging methods of MAP can prolong microbial-shelf life and maintain higher WHC of beef steaks compared to AP and VP steaks, but higher oxidation level in HiO₂ MAP and unattractive colour in HiCO₂ MAP are concerns that need to be addressed.     

Multilayered antimicrobial polyethylene films applied to the packaging of ground beef

A natural antimicrobial agent, grapefruit seed extract (GFSE), was incorporated in a 0.5% or 1.0% concentration on the food‐contact surface of multilayered polyethylene (PE) film by a co‐extrusion or solution‐coating process. The fabricated films were tested in their antimicrobial activity against several food spoilage microorganisms, and then applied to the packaging of ground beef. During the storage of the packaged beef at 3°C, changes in microbial counts, pH, TBA value and meat colour were monitored in order to see the effect of the packaging film on meat quality changes. Coating the PE film with GFSE with the aid of a polyamide binder resulted in a more effective level of antimicrobial activity on the agar plate medium than did its incorporation by a co‐extrusion process. The film co‐extruded with a 1.0% GFSE layer showed antimicrobial activity only against Micrococcus flavus ATCC 10240, while the film coated with 1.0% GFSE showed activity against several microorganisms, such as Escherichia coli IFO 3301, Staphylococcus aureus IFO 3060 and Bacillus subtilis IFO 12113. Both types of GFSE‐incorporated multilayer PE films contributed to a reduction of the growth rates of aerobic and coliform bacteria on the ground beef, when compared to plain PE film. The film coated with a higher concentration (1.0%) of GFSE had a more pronounced effect than did the other films in inhibiting spoilage bacterial growth. They could also slow down chemical changes of the packaged beef. The GFSE‐coated film was more effective in preserving beef quality, but the level of GFSE addition did not affect the quality changes of the beef. Copyright © 2001 John Wiley & Sons, Ltd.     

解冻技术在肉制品中的应用研究进展

目的 对国内外肉品解冻技术的研究进展进行综述,以提高解冻效率和解冻肉的品质.方法 阐述各种解冻技术对肉制品的作用机理,分析其优势和限制其推广应用的关键问题;论述应用于牛肉、猪肉和羊肉的解冻工艺,并对肉品解冻的未来研究方向进行展望.结论 各种解冻技术均有利弊,对于牛肉,高压静电解冻技术虽是一种极具潜力的新型解冻技术,但仍存在解冻规模小和生产成本高等问题;对于猪肉,低温高湿解冻较适用于实际生产;对于羊肉,冷水和低温空气解冻是较为合适的方法.未来可根据不同肉制品的特性,有针对性地研究其解冻工艺.同时,也应对组合解冻技术和肉品的预处理技术进行研究,以提高冻肉的解冻效率和品质.     

实验显示减压冷藏技术在生鲜净菜小包装加工流通中有应用前景

生鲜蔬菜经过减压冷藏,然后清洗、切碎后进行简单包装,可延长冷藏货架期和无温度控制环境货架期两者。初步实验表明减压冷藏技术在生鲜净菜小包装加工流通中有应用前景。     

天然活性包装膜在冷冻肉贮藏中的应用研究进展

目的 对天然活性包装膜在冷冻肉贮藏中的应用研究进展进行总结,为后续研究提供理论参考。方法 在介绍反复冻融对冷冻肉品质影响的基础上,围绕天然活性包装膜的功能成分、成膜工艺及其在冷冻肉贮藏中的应用研究予以阐述,讨论现有研究的局限性和今后的研究方向。结果 冻融过程中冰晶的反复形成影响冷冻肉体系的细胞结构和理化性质,加剧肉品品质下降;天然活性包装膜可以通过降低干耗、抑制氧化等延长肉品货架期。结论 天然活性包装膜可有效保护冷冻肉品,在肉品保鲜领域具有广阔的应用前景。