Mode of action of lactocin 705, a two-component bacteriocin from Lactobacillus casei CRL705

Lactocin 705 is a bacteriocin whose activity depends on the complementary action of two peptides (705alpha and 705beta) of 33-amino-acid residues each and is produced by Lactobacillus casei CRL705. Biologically active, synthetic lactocin 705 was used to study the mode of action on sensitive cells of Lactobacillus plantarum CRL691. The addition of 90 nmol l(-1) of lactocin 705 to cells of L. plantarum dissipated both, the membrane potential (DeltaPsi) and the pH gradient (DeltapH). Energized membrane, obtained after the addition of glucose, were more susceptible to lactocin 705 action leading to the immediate release of intracellular K(+) and inorganic phosphate. When the role of various ions on sensitive cells were analyzed, only Ca(2+) ion exhibited a protective effect against lactocin 705. These data suggest that the presence of a proton motive force (PMF) promotes the interaction of the bacteriocin with the cytoplasmic membrane of energized cells, leading to pore formation which allows for the efflux of ions, thereby ensuring efficient killing of target bacteria.     

The control of Listeria innocua and Lactobacillus sakei in broth and meat slurry with the bacteriocinogenic strain Lactobacillus casei CRL705

The effect of the bacteriocin-producing strain, Lactobacillus casei CRL705, in the control of Listeria innocua 7 and Lactobacillus sakei CRL1424 in MRS medium and meat slurry during the storage under vacuum at chill temperatures was evaluated. L. sakei CRL 1424 isolated from vacuum-packaged contaminated raw meat was identified as the predominant indigenous lactic acid bacterial flora. Co-inoculation of MRS broth at 8°C with L. casei CRL705 caused growth inhibition of L. sakei CRL1424 and L. innocua 7 after 10 and 4 days of storage, respectively. At 4°C the complete inhibition of both strains occurred within 14 and 8 days for L. sakei CRL1424 and L. innocua 7, respectively. Bacteriocin activity in broth was observed to be maximal at 8°C reaching 2130 AU ml⁻¹ after10 days and 400 AU m1⁻¹ after 8 days of storage, while at 4°C maximal activities, 690 and 30 AU ml⁻¹ were obtained at 14 and 10 days, respectively. Addition of bacteriocinogenic strain to the meat slurry did not allow the growth of L. sakei and L. innocua, showing a bacteriostatic effect during 21 days of storage at 4°C. In addition, L. casei CRL705, as a protective culture did not change significantly the pH of the meat slurry in the assayed storage conditions. The results presented here confirm that the bacteriocinogenic strain L. casei CRL705 can be used as a useful tool to improve the microbial stability and safety in the commercial meat preservation.     

复合添加物在腌制过程中对兔肉传质动力学和肌原纤维蛋白的影响

以兔肉为原料,研究5种不同复合添加物(食盐为对照组、"食盐+亚硝酸钠"记为Y组、"食盐+亚硝酸钠+香辛料"记为YY组、"食盐+亚硝酸钠+香辛料+磷酸盐"记为YL组、"食盐+亚硝酸钠+香辛料+磷酸盐+调味料"记为YW组)在腌制过程中对兔肉传质动力学和肌原纤维蛋白的影响。结果表明:复合添加物对兔肉水分变化量、食盐变化量、总重变化量(△M_t~w、△M_t~(NaCl)、△M_t~0)有一定影响,但差异不显著(P0.05);复合添加物降低了腌制兔肉的De值,且Y组De值最小,为9.63×10~(-10) m~2/s;复合添加物不同程度改变了腌制兔肉的持水力和硬度,相比对照组,YL、YW组的持水力显著增加(P0.05)、硬度显著降低(P0.05),Y、YY组的持水力没有显著变化(P0.05)、但硬度变化明显(P0.05);复合添加物降低了肌原纤维蛋白储能模量(G')(P0.05),且与对照组相比,Y、YY组肌球蛋白变性温度提高,Y、YL和YW组肌动蛋白变性温度降低;SDS-PAGE电泳分析表明,复合添加物促进肌原纤维蛋白不同程度降解,且YL组的降解程度最大。     

Evaluation of the thermal resistance of different Salmonella serotypes in pork meat containing curing additives

The preliminary heat resistance evaluation of 94 Salmonella strains was carried out in culture medium (Trypticase soy broth, TSB). The heat resistance of three S. typhimurium strains (ATCC 14028, 133 and 1116), a strain each of S. derby B4373, S. potsdam 1133, S. menston 179. S. eppendorf 166, and S. kingston I124 was determined also in pork meat containing curing additives. As expected, the eight Salmonella strains showed greater heat resistance in pork meat than in TSB. At the lowest temperature (58 degrees C), the heat resistance increased 1.5-4 times, and it was most pronounced for the strains being most heat sensitive in TSB. S. potsdam 133 was the most resistant strain in pork meat, with D-values at 58 degrees C, 60 degrees C and 63 degrees C of 4.80, 1.57 and 0.30 min, respectively. The most sensitive strain turned out to be S. kingston 1124, with D-values of 2.79. 0.92 and 0.24 min, at the same temperatures. According to collected data, the heating processes, as applied to cured pork meat, providing an internal temperature of 60 degrees C for 9-10 min or of 63 degrees C for 3-4 min can be expected to provide a > or = 7 D kill of Salmonella belonging to the serotypes studied.     

不同腌制方式对猪肉腌制速率及肉质的影响

为缩短腌制时间,降低生产成本,指导腊肉的快速腌制,以常压液腌为对照,探讨了常压滚揉,真空滚揉、脉动真空滚揉3种腌制方式对猪肉p H值、腌制液吸收百分比、蒸煮损失、剪切力和食盐含量的影响。结果显示,4种腌制方式下,猪肉的p H值总体呈上升趋势,但相邻检测点间差异不显著(p>0.05);脉动真空滚揉、真空滚揉与常压滚揉的腌制液吸收百分比高于常压液腌,其中脉动真空滚揉腌制的腌制液吸收百分比最大;脉动真空滚揉腌制后的蒸煮损失与剪切力跟其他3种腌制方式相比最小;在达到相同的食盐含量时,脉动真空滚揉腌制所需要的时间最短。结果表明,脉动真空滚揉腌制猪肉效果较好。     

广式腊味氧化问题的研究

文章主要研究广式腊味酸价、过氧化值、TBA值三者之间的相互关系和储藏温度对三者的影响,以及广式腊味的风味变化情况.研究结果表明,广式腊味酸价的变化规律与过氧化值、TBA值的变化规律的相关性不显著.保藏温度越高,广式腊味酸价、过氧化值和TBA值在储藏过程中升高速率越大.储藏时间是影响TBA值更为重要的因素.酸价超标的样品其感官品质也未发生不良变化.所以,酸价和过氧化值在评价广式腊味脂肪氧化程度上并不一致,都不能作为其合适的指标;TBA值是反映广式腊味脂肪氧化程度的最合适指标.     

添加剂在肉制品加工中的应用

肉制品工业的发展离不开添加剂的应用。肉制品加工中应用的添加剂种类丰富,包括防腐剂、抗氧化剂、护色剂、增香剂、乳化剂、水分保持剂、增稠剂等。在综述了肉制品加工中常用添加剂的性状、作用机理、使用方法及注意事项的基础上,还对肉制品加工添加剂的应用现状和最新的研究进展做了一定的归纳和总结,为肉制品加工中添加剂的选择、使用以及新产品开发提供有益参考和指导。     

食品添加剂的作用与安全性控制

随着我国食品工业的发展,食品添加剂发挥着越来越重要的作用,并已成为食品工业的灵魂,没有食品添加剂就没有现代食品工业已成为食品界人士的共识。但是近年来发生的一系列食品安全事件,使社会和公众对食品添加剂产生了误解,认为食品添加剂是食品安全的主要问题,并造成了一些不良影响。事实上,那些引起食品安全事件发生的根本不是食品添加剂,而是一些非法添加物。为了使社会和公众正确认识食品添加剂,食品企业科学合理使用食品添加剂,中国食品添加剂和配料协会在今年3月举办的大型FIC展会期间,与中国卫生监督协会共同举办了"食品添加剂安全性管理高层论坛",此次高层论坛旨在广泛宣传贯彻执行《食品安全法》,正确认识食品添加剂对现代食品工业发挥的巨大作用,给社会和公众传递正确的食品添加剂相关信息,使我们的老百姓不再误解和惧怕食品添加剂;使我们的食品添加剂和食品生产经营企业更加全面了解我国食品添加剂管理的法律法规,加强行业自律,严格依法依规办事,保障食品安全。为此,本刊从第3期开始特设了"专家论坛"栏目,陆续选登在"食品添加剂安全性管理高层论坛"上权威专家和领导的精彩演讲,与读者共同分享他们的精辟论道。本期首先刊登原卫生部卫生监督局局长、现任食品安全国家标准审评委员会食品添加剂专业分委员会主任委员、中国卫生监督协会常务副会长兼秘书长、中国卫生法学会副会长赵同刚先生题为"食品添加剂的作用与安全性控制"的演讲内容。希望他的演讲能对全社会和从事食品添加剂的生产、经营和使用等各方面的人士提供有价值的参考和帮助。     

食品添加剂在肉制品保藏中的应用

介绍了肉制品保藏中常用的食品的添加剂的功能特性及其应用。     

Analysis of commercial soya additives in meat products

The quantitative aspects of the analysis of commercial soya additives in meat products have been investigated using a polyacrylamide gel electrophoresis technique. Extraction of the proteins from the food products was carried out either in 8 M -urea and 1%, 2-mercaptoethanol at 18 to 20 °C for 16 h (Method 1), or 10 M -urea and 4%, 2-mercaptoethanol at 100 °C for 30 min (Method 2). The proteins in the extracts were separated by electrophoresis on gels containing 6% polyacrylamide and either 6 M -urea (Method 1) or 8 M -urea (Method 2) using a 0.06 M -Tris-glycine buffer, pH 8.6. Densitograms of the stained protein bands were used for the quantitative estimation of the soya proteins. Both methods were found to give quantitative results for the analysis of soya protein additives in beefburgers and sausages. Method 1 was also found to give quantitative results for meat pie fillings and canned meat loaf products, which had been autoclaved at 115 °C for 40 min.     

Detection of allergenic additives in processed meat products

Allergic responses to food components are an increasing problem all over the world. It is therefore important to protect people who are vulnerable to food allergens against accidental and unintended consumption of products containing allergic ingredients. The meat industry commonly uses various allergic additives in the production of processed products, such as legumes (soy, peas, beans), milk and egg preparations, cereals containing gluten (wheat, rye, barley and oats), and spices (celery and mustard). These meat additives have specific technological properties, which help to create a texture or flavor profile, or affect the nutritional value, although some of them, such as soy, mustard, milk and egg white proteins, can cause severe allergic reactions. The aim of this paper is to discuss the application of various recently established methods of detection of allergenic additives in processed meat products – for instance cold cuts and sausages. The new methods are based mainly on protein, DNA, and isoflavones or phytic acid analysis. The article also characterizes the latest trends in the development of research on methods that would enable quick and reliable identification of targeted allergens in meat products. © 2018 Society of Chemical Industry     

真空腌制与传统腌制加工过程中腊肉的品质变化

研究真空腌制和传统腌制加工过程中腊肉质量变化规律。对两种腌制方式腊肉在不同加工阶段的水分和食盐含量、亚硝酸钠残留量、微生物指标、颜色及挥发性风味物质种类及相对含量进行比较。结果表明:腌制完成后,真空腌制和传统干腌样品的水分含量分别下降16.5%和20.5%;食盐含量分别升至5.9%和5.2%;真空腌制的样品与传统干腌法的相比L*值高2.1%,a*值低12.2%,b*值差异不显著,菌落总数较低,球菌成为主要的优势菌种。烘烤烟熏完成后,与传统干腌法相比,真空腌制的腊肉样品水分、食盐和亚硝酸钠的含量更高;L*值高于传统干腌法,a*、b*值较低,使得腊肉色泽更佳,肉质呈愉悦的玫瑰粉红色;真空腌制腊肉中球菌和霉菌的数量高于传统干腌法,成为优势菌种,其他菌种的差异性不显著。加工过程中,同一阶段真空腌制的样品检测出的挥发性风味物质的种类及相对含量均高于传统干腌法。因而真空腌制能起到提高腊肉的保水性、促进腌制剂的吸收及改善腊肉风味和颜色的作用。     

Effects of some technologies of curing uncomminuted meat products on their flavour Part 1. Changes in the contents of fatty acids as meat flavour precursors

A study was made of the fatty-acid composition of phospholipids and the fraction of free fatty acids in two uncomminuted pork products, loin and neck, manufactured by three technologies: I, brine curing; 11, dry curing; 111, dry curing using%.6% honey. A higher phospholipid content was found in the loin products. Brine curing caused a more intensive lipid hydrolysis in both types of meat products. The free fatty-acid fraction in the meat products manufactured by technologies II and III was richer in unsaturated fatty acids, which are some of the most important meatflavour precursors.     

国内外肉制品中食品添加剂硝酸盐和亚硝酸盐的标准管理探讨

目的 探讨肉制品中食品添加剂硝酸盐和亚硝酸盐的标准管理.方法 通过对国际食品法典以及美国、加拿大、欧盟、澳新、日本、韩国和中国肉制品中硝酸盐和亚硝酸盐食品添加剂标准规定的分析,结合风险评估、监测结果和食品中毒事件数据分析的情况,探讨相关标准未来的发展方向.结果 从生产加工过程控制、终产品检测可操作性或进出口口岸检测便利...     

肉类食品添加剂的应用现状与趋势

对肉制品加工中常用的防腐剂、抗氧化剂、增稠剂、颜色保持剂和香精香料等主要添加剂的研发应用现状进行了综述,并对其发展趋势进行了介绍和展望。     

Effects of additives and thermal treatment on the content of nitrogen compounds and the nutritive value of hake meat

Heating of minced meat from 40 to 130 degrees C for 10 min and at 120 degrees C from 15 to 60 min with potato starch (3%), soya oil (4%), salt (1.5%), and water (15%) resulted in a decrease in total amino-acid content by 6% on the average, compared to the content in meat without additives. Heating time-dependent changes involved a decrease in the lysine content, while temperature-dependent changes involved a decrease in the valine content. On the other hand, the presence of additives reduced the thermal protein hydrolysis towards the formation of low-molecular nitrogen compounds. Prolonged time of heating of minced hake meat at 120 degrees C produced a more intensive protein hydrolysis than a shorter heating up to 130 degrees C; at the same time with temperatures exceeding 100 degrees C an intensive increase in the ammonia content, decrease in -SH groups content, and a decrease in protein digestibility were observed.     

广式腊肠、腊肉风味物质研究进展

广式腊味是我国传统的风味食品,其口味独特,外形美观,肉嫩香醇,营养丰富,食用简便,深受消费者的喜爱。腊肠和腊肉是两种传统的广式腊味,其独特的风味更形成地方特色,文章综述了广式腊肠特征风味物质的来源、种类及检测方法,概括了广式腊肉与四川、湖南腊肉特征风味物质的区别,并对广式肉制品风味物质保持的研究进行了总结,得出:脂肪氧化是广式腊味的一个重要风味来源;醇类、酯类是腊肠香气成分的重要组成;采用GC-MS法分析香气成分简便快捷;抗氧化技术的发展对于腊味风味保持有重要贡献。     

腌制提高牦牛肉加工制品品质的研究

以牦牛肉为原料采用正交试验设计,探讨了腌制剂配方及腌制工艺对牦牛肉加工制品品质的影响,结果表明:CaCl2、木瓜蛋白酶、复合磷酸盐的浓度分别为3%、0.005%、0.5%,并采用干腌法效果最佳。     

翘嘴红鲌肉腌制工艺优化

目的研究腌制方式和湿腌温度、时间对翘嘴红鲌肉品质的影响。方法以挥发性盐基氮(volatile salt-based nitrogen,VBN)、菌落总数(aerobic plate count,APC)、过氧化值(peroxide value,POV)及感官评分为指标,比较干腌与湿腌法对翘嘴红鲌鱼肉制品品质的影响,在此基础上以腌鱼肉盐分含量、感官评分及盐卤中氨基酸态氮及可溶性蛋白含量为指标,确定最适湿腌条件。结果冷藏后期干腌组鱼肉VBN、APC显著高于湿腌组鱼肉,而感官评分低于湿腌组鱼肉,湿腌组比干腌组鱼肉保质期延长2~3 d;同一腌制温度下,湿腌组鱼肉含盐量、盐卤中氨基酸态氮和可溶性蛋白的含量均随腌制时间延长而增加,最佳腌制工艺为:10~15℃湿法腌制20 min,腌制后鱼肉营养损失相对较少,鱼肉盐分含量约为4.09%。结论相比于干腌法,湿法腌制翘嘴红鲌肉更有利于腌鱼肉的保藏;合适的湿腌温度和时间分别为10~15℃和20 min,此时腌鱼肉具有较好的感官品质,冷藏条件下保质期能达到18 d左右。     

Stabilization of meat lipids with nitrite-free curing mixtures

Several nitrite-free meat-curing mixtures have been formulated. The mixtures included salt, sugar, ascorbates, an antioxidant and/or a chelator, an antimicrobial agent and dinitrosyl ferrochemochrome (DNFH). They imparted to meat a similar oxidative stability as that of sodium nitrite. Butylated hydroxyanisole and t-butylhydroquinone were the best anti-oxidants and polyphosphates, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid were the superior chelators. The antimicrobial agents used were potassium sorbate, propryl paraben, fumarate esters and sodium hypophosphite. In the above mixtures, the added effect of (DNFH) on oxidative stability of the cooked meats was similar to the added effect of 150 ppm sodium nitrite.