酵母和加工条件对冷冻面团生产的影响

综述了酵母和加工条件对冷冻面团生产的影响,介绍了如何通过选择酵母种类、改善配方、改进制作方法及控制冷冻解冻条件等来改善冷冻面团的稳定性.     

Effect of a gelatin coating on the shelf life of fresh meat

ABSTRACT:  The end of shelf life for fresh meat is determined by unacceptable aroma, appearance, and color, which appear before unacceptable microbial counts. Addition of a bovine gelatin coating to fresh meat may extend its shelf life. This study utilized a 20% bovine gelatin solution that was spray-coated onto beef tenderloins, pork loins, salmon fillets, and chicken breasts which were packaged in an 80% O₂ and 20% CO₂ modified atmosphere and stored under fluorescent light at 4 °C for 2 wk. All of the gelatin-coated fresh meat products showed a reduction in purge. The gelatin reduced purge by acting as a barrier to water loss. There was a reduction in color deterioration for gelatin-coated beef, a slight reduction of color deterioration for gelatin-coated pork, and no reduction in color deterioration for salmon and chicken. The gelatin coat reduced color deterioration by acting as a barrier to oxygen, but also had a negative effect on color due to its own color deterioration. No change in lipid oxidation was seen with any of the gelatin-coated meat products. The gelatin coat was not an effective barrier for lipid oxidation at refrigeration temperatures. Sensory analysis of beef tenderloins confirmed that color deterioration was reduced, and flavor was not affected by the application of a gelatin coat. The gelatin coat was equally effective during light and dark storage. It was more effective on vacuum packaged products than on modified atmosphere packaged products.     

利用罗非鱼酶解液进行美拉德反应制备肉类风味物的研究

以罗非鱼下脚料的酶解液为原料，添加其他一些反应基质如：半胱氨酸盐，硫胺素盐酸盐(VB1)，还原糖等通过美拉德反应合成肉类风味物。实验表明，反应的最佳条件是：温度121℃，时间60min，pH值5．0～6．0，各种基质的添加量分别为：L-半胱氨酸盐1mmol，硫胺素盐酸盐(VB1)0．3mmol，木糖1．5mmol，葡萄糖4．5mmol。     

微生物酶与肉组织酶对干发酵香肠中游离脂肪酸的影响

以戊糖乳杆菌31-1和木糖葡萄球菌为发酵剂生产干发酵香肠,就发酵剂对干发酵香肠成熟过程中游离脂肪酸的影响进行了研究。研究结果表明,在灌肠后的1周内,脂肪的水解主要是由组织酶引起的,微生物对脂肪微弱的水解能力主要表现在干发酵香肠成熟的后期,并且发酵剂不能改变发酵香肠中游离脂肪酸的变化模式。     

应用多靶栅栏技术控制羊肉生产与贮藏过程中的微生物

在冷却羊肉的生产过程中 ,可以运用表面清洗消毒、添加化学生物防腐剂、真空包装、低温贮藏等栅栏因子对羊肉产品的微生物进行控制。有效的多靶栅栏组合是采用 5 0mg/L稳定态ClO2 对胴体进行表面消毒 ,添加 0.0 1%乳酸链球菌素和 1%乳酸钠 ,真空包装后于 (4± 1)℃贮藏 ,可以使冷却分割羊肉的货架期达到 30d。     

液质联用测定肉制品中氟尼辛葡甲胺前处理方法的优化

以液相色谱-四级杆串联质谱法(LC-MS/MS为检测手段,通过考察回收率大小测定肉制品中氟尼辛葡甲胺的残留量,并对其的前处理条件进行了优化,最终确定了肉制品中氟尼辛葡甲胺前处理方法:采用乙腈-乙酸乙酯(11V/V提取,PCX固相萃取小柱净化,用正己烷-乙酸乙酯(91V/V淋洗,甲醇和氨化甲醇(595V/V洗脱,再用体积浓度0.1%甲酸(含0.5 mmol/L乙酸铵)定容,待测。方法回收率为85.0%110.0%相对标准偏差(RSD6.0%。     

HDA法用于检测肉中金黄色葡萄球菌的研究

本文研究了猪肉、牛肉、羊肉、鸡肉中金黄色葡萄球菌的依赖解旋酶恒温基因扩增检测方法(HDA法),以金黄色葡萄球菌耐热核酸酶nuc基因为目的基因,设计一对特异性引物,优化反应条件UvrD helicase、T4 gp32的浓度,通过赖解旋酶恒温基因扩增方法直接检测猪肉、牛肉、羊肉、鸡肉中金黄色葡萄球菌,扩增产物通过电泳进行检测。结果表明,HDA法检测肉中金黄色葡萄球菌的特异性强,试验涉及的其它菌株未发生扩增,只有金黄色葡萄球菌得到与设计序列长度一致的216 bp基因片段,检出限为101 CFU/g,优化确定UvrD helicase、T4 gp32的终浓度分别为0.1 μg、5.0 μg,该方法用于检测猪肉、牛肉、羊肉、鸡肉中金黄色葡萄球菌的灵敏度高,耗时短,为猪肉、牛肉、羊肉、鸡肉中金黄色葡萄球菌的快速检测提供了新的方法,也为其它食品中金黄色葡萄球菌的快速检测奠定了基础。     

肉类及蔬菜食品中EHEC O157污染分布及分型研究

为深入了解肉类及蔬菜中肠出血性大肠埃希氏菌(EHEC O157)的污染分布规律和遗传多样性,随机采集全国18个城市的食品样品,参考GB/T 4789.36-2008方法进行样品处理,并用rfbE/fliCH7双重PCR对菌株进行鉴定;分别采用单重PCR和ERIC-PCR对菌株进行毒力基因(eae、hlyA、stx1和stx2)检测和分子分型。结果表明,414份样品中检出18份EHEC O157阳性样品,总污染率4.35%,其中生鲜肉12份,速冻肉6份,蔬菜未检出;经过生化、血清鉴定和双重PCR检测,鉴定出52株EHEC O157,包括29株O157:H7,3株O157:NM(fliCH7+,无动力),2株O157:NM(fliCH7-,无动力)和18株O157:hund(未确定H型);毒力基因检测结果发现,52株菌株中有50株携带毒力基因,其中40株(76.92%)携带eae,31株(59.62%)携带hlyA,20株(38.46%)携带stx1,24株(46.15%)携带stx2。ERIC-PCR分型结果表明,在相似系数为0.80时,菌株可分为12个聚类簇,F型为其主要基因簇,分离株的基因型呈现多样性。     

不同宰前运输时间对羊肉品质的影响

宰前运输处理是影响畜禽肉品质的重要宰前因素之一。选取6月龄乌珠穆沁羊与小尾寒羊杂交公羊40只,分别进行宰前运输0 h(对照)、1 h、3 h和6 h处理,分析羊肉食用品质、感官品质及蛋白质特性,研究不同宰前运输时间对羊肉品质的影响。结果表明,运输处理组羊肉宰后24 h pH值、剪切力显著高于对照组,分别上升0.54~2.90%和15.60~24.61%(P0.05)。宰前运输3 h、6 h分别使羊肉ΔE值显著升高6.12%和6.50%,使感官评价总体可接受性得分显著下降13.51%和20.82%(P0.05)。宰前运输6 h组羊肉蒸煮损失显著低于对照组,降低了7.37%(P0.05)。宰前运输1 h组羊肉宰后降解程度低于对照组(P0.05)。宰前运输1 h、3 h和6 h对羊肉品质造成不同程度的消极影响,因此,宰前应尽量避免运输或运输后采取其他宰前操作使羊从运输应激中恢复。     

Cultured beef: from small biopsy to substantial quantity

Cultured meat is an emerging technology with the potential to solve huge challenges related to the environmental, ethical, and health implications of conventional meat production. Establishing the basic science of cultured meat has been the primary focus of the last decade but it is now feasible that cultured meat products will enter the market within the next 3 to 4 years. This proximity to market introduction demands an evaluation of aspects of the cultured meat production process that have not yet been outlined or discussed in significant detail. For example, one technological approach for the production of cultured meat uses adult muscle stem cells, the limited proliferative capacity of which necessitates repeated collection of tissue samples via biopsies of living donor animals. The selection of donor animals and the details of biopsy processes must be optimized, as this is a key bottleneck in the cultured meat production process. The number of stem cells harvested from a biopsy, together with their proliferative capacity, determines a ‘multiplicity factor’ achieved by a cultured meat production process, thus dictating the reduction in number of animals required to produce a given quantity of meat. This article considers potential scenarios for these critical upstream steps, focusing on the production of cultured beef as an example. Considerations related to donor selection and details of the biopsy process are discussed in detail. The practicalities of various scenarios for cultured beef production, the health of donor animals, and regulatory issues associated with the safety of cultured meat for consumers are also considered. © 2020 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.