Antibacterial Interactions of Monolaurin with Commonly Used Antimicrobials and Food Components

ABSTRACT:  Monolaurin is a nontraditional antimicrobial agent that possesses better antimicrobial activities but causes no health problems to consumers, but the use of monolaurin in the food industry as a preservative is still limited. Using a microtiter plate assay, the minimum inhibitory concentrations for monolaurin were 25 μg/mL against  Escherichia coli , 12.5 μg/mL against  Staphylococcus aureus , and 30 μg/mL against  Bacillus subtilis . The interaction with commonly used antimicrobials revealed that monolaurin and nisin acted synergistically against the test microorganisms, monolaurin in combination with sodium dehydroacetate or ethylenediaminetetraacetic acid was synergistic against  E. coli  and  B. subtilis  but not  S. aureus , and monolaurin combined with calcium propionate or sodium lactate showed no synergistic effects against any test microorganism. The interaction with food components revealed that the antibacterial effectiveness of monolaurin was reduced by fat or starch while the monolaurin activity remained unchanged in the presence of protein. This study contributes to a better understanding on the use of monolaurin as a nontraditional preservative in food products. Results from this study suggest the potential use of monolaurin as a nontraditional preservative in combination with commonly used antimicrobials, such as nisin, sodium dehydroacetate, or ethylenediaminetetraacetic acid, and suggest that the antibacterial effectiveness of monolaurin may be reduced significantly in high-fat or low-starch food products.     

国家食品标签通用标准的几点说明

1994年2月4日经国家技术监督局批准发布了GB7718－94国家标准一食品标签通用标准，并规定从1995年2月1日开始实施。该标准是强制性标准，也就是说凡是在中华人民共和国国内销售、生产的产品标签都必须按标准规定的要求标注。为此，着重说明以下几个问题：一、食品标签的作用首先，什么是食品标签。食品标签是指预包装食品容器上的文字、图形、符号及一切说明物。预包装食品是指预先包装于容器中，以备交付给消费者的食品。容器是指将食品完全或部分包装，以作为交货单元的任何包装形式，也包括包装纸。这样，食品标签的作用显而易见在于：…     

Flow Properties Of Encapsulated Milkfat Powders as Affected by Flow Agent

Food powders containing softer cores of fatty or flavor components present handling problems, as such powders are generally of very low density and mostly non free-flowing. Three classes of flow conditioners [silica, silicate and stearate], at three levels of concentration, were evaluated to determine effects on bulk and flow properties of sucrose, lactose and modified corn starch as well as butter oil powders encapsulated with the same materials. Silica and silicate were generally effective in improving bulk properties but only silica was effective in improving flow-ability of unencapsulated powders as well as lactose-encapsulated butteroil powder. Washing with isopropanol was effective in improving flow only with the lactose-encapsulated butteroil powder. Butteroil encapsulated in lactose had flow characteristics similar to lactose.     

皮革科技论文中关键词的引用分析及部分关键词推荐(Ⅱ)——常用关键词推荐

鉴于目前部分皮革科技论文中关键词标引不规范的现状,搜集了皮革及相关行业的常用词汇,并结合中国轻工业标准汇编,分类列举了常用主题词及标准行业词汇,以供皮革科技论文作者在标引关键词时参考使用。     

Comparative Absorption of Low Molecular Aroma Compounds into Commonly Used Food Packaging Polymer Films

Five polymer films commonly used in food packages were stored in an aqueous solution of 10 apple aroma compounds. Substances absorbed by the polymers were determined by a supercritical fluid extraction/gas chromatography method. Polypropylene absorbed most aromas, more than 2× amounts absorbed by low density polyethylene. Polyamide and polyester absorbed very small amounts of the aromas. Esters and aldehydes were absorbed much more than alcohols. Molecular size also affected absorption, larger molecules being absorbed to a greater extent than smaller ones. For most materials the absorption equilibrium was reached within a week.     

Effect of Composition on the Flow Properties of Egg Powders

Flow properties of two classes of egg powder were studied. Whole egg with corn syrup and salt (CEP) exhibited better flow properties than whole egg powder (WEP). Free-flowing characteristics of both powders decreased with increased temperature. Moisture content was found to have significant affect on the flowability of CEP, but not WEP, at level as low as in the (B.E.T.) monolayer region [Brunauer et al. (1938), JACS 60: 309]. Lipid, on the other hand, was shown to be the dominant factor in preventing easy flow of WEP. This was related to the presence of surface lipid that contributed to the cohesiveness between particles.     

功能性食品添加剂 N-乙酰-D-葡糖胺的理化性质

N-乙酰-D-葡糖胺是一种具有多种生理活性和功能性质的重要氨基糖 .实验研究了NAG的一些重要理化性质和加工稳定性 ,为NAG在食品中的应用提供理论依据 .结果表明 ,NAG易溶于水 ,微溶于乙醇 ;NAG晶体在 1 2 0℃、6h下保留率大于 98% ,性质稳定 ;在 1 0 0℃、6h、pH 3 .0～8.5的条件下 ,NAG水溶液稳定性好 ,pH超过 8.5则保留率大大降低 ,并伴有颜色变化 ;NAG在牛奶杀菌条件下性质稳定 ;NAG不具有吸湿性和保湿性     

邱博合成无定形二氧化硅和硅酸盐作为助流剂和抗结剂广泛应用于粉末食物

精细研磨的合成无定形二氧化硅和硅酸盐有效地用于粉末食物中,以提高产品的流动性和抑制产品结块。根据食物颗粒之间流动性差或结块的情况,可通过颗粒间互相作用的最小化来解决。弄清了颗粒间自然的相互作用后,我们将会针对邱博二氧化硅和硅酸盐如何使食物颗粒间的相互作用达到最     

皮革常用染料概述

1皮革染料的基本概念能溶于水及溶剂,具有一定坚牢度的有色物质称为染料。用于蛋白质皮革纤维染色的染料又称为皮革用染料。皮革染料除要求具有鲜艳的颜色外,还要对皮革纤维具有良好的亲和力和各项坚牢度功能,如耐晒牢度、耐水洗、耐干湿摩擦等专业指标。2皮革染料的分类2.1普通常用的皮革染料目前国内市场上的酸性染料、直接染料、其分子结构为单偶氮染料,颜色鲜艳,但皮革染色牢度相对较差,且价格低廉,所谓的皮革染料市场的酸性黑、直接黑都属经济型皮革染料。     

Effect of Equilibrium Water Activity on the Bulk Properties of Selected Food Powders

The bulk properties of powdered coffee creamer, infant formula, salt and sucrose at different levels of water activity were characterized by mechanical methods. These included loose bulk density, compressibility, cohesion, % irrecoverable work in compression and asymptotic modulus after stress relaxation. In the crystalline powders the physical characteristics generally followed the pattern established by the moisture content with an apparent critical water activity beyond which changes became drastic. In the creamer and formula which were very cohesive even in the dry form, the changes in bulk properties were generally more gradual. The rheological tests indicated that much of the physical changes in the salt and sucrose powders could be attributed to surface moisture. In the creamer and formula the plasticity of the particles material was also a major factor that affected the bulk behavior.     

层间加填中黏合剂的特性及复配比例对成纸性能的影响

以废纸抄造瓦楞原纸,选用重质碳酸钙为填料,苯丙乳液与两种取代度不同的阳离子淀粉为黏合剂,考察了黏合剂的种类、用量以及不同黏合剂的复配比例对成纸物理强度性能的影响。结果表明:采用苯丙乳液作为黏合剂的效果优于两种取代度不同的阳离子淀粉,而低取代度的阳离子淀粉又优于高取代度阳离子淀粉。当碳酸钙填加量为25%(相对于绝干浆),苯丙乳液与阳离子淀粉以1:4的比例复配,用量为2%时,虽纸张的抗张强度略有下降,但纸张的环压强度及内结合强度高于单独使用阳离子淀粉或苯丙乳液的纸张。     

Antioxidant and Anti-inflammatory Activities of Several Commonly Used Spices

ABSTRACT: Antioxidant and anti-inflammatory activities are extensively used to screen chemo-preventive foods. Five well-known anticancer spices, ginger, red pepper, garlic, green onion, and leek, were selected and assessed in this study. Antioxidant function was evaluated based on the scavenging ability of the cation radical ABTS⁺. Moreover, anti-inflammatory activity was determined based on the inhibitory effect of nitric oxide (NO) production by lipopolysaccharide (LPS)-activated macrophages. The antioxidant activity of the 5 spices followed this order: ginger > red pepper > leek > green onion and garlic. All of these spices had a strict inhibitory effect on NO production. The anti-inflammatory activity could be ranked based on the IC₅₀ of the spices, as garlic > ginger > green onion > leek and red pepper. Additionally, a significant correlation existed between antioxidant activity and total phenolics content. Obviously, total phenolics content was a crucial determinant of the antioxidant but not the anti-inflammatory activity of foods. The compounds responsible for the anti-inflammatory activity should differ from those responsible for the antioxidant activity.     

Biofilm Formation by Shiga Toxin-Producing Escherichia coli O157:H7 and Non-O157 Strains and Their Tolerance to Sanitizers Commonly Used in the Food Processing Environment

Shiga toxin-producing Escherichia coli (STEC) strains are important foodborne pathogens. Among these, E. coli O157:H7 is the most frequently isolated STEC serotype responsible for foodborne diseases. However, the non-O157 serotypes have been associated with serious outbreaks and sporadic diseases as well. It has been shown that various STEC serotypes are capable of forming biofilms on different food or food contact surfaces that, when detached, may lead to cross-contamination. Bacterial cells at biofilm stage also are more tolerant to sanitizers compared with their planktonic counterparts, which makes STEC biofilms a serious food safety concern. In the present study, we evaluated the potency of biofilm formation by a variety of STEC strains from serotypes O157:H7, O26:H11, and O111:H8; we also compared biofilm tolerance with two types of common sanitizers, a quaternary ammonium chloride-based sanitizer and chlorine. Our results demonstrated that biofilm formation by various STEC serotypes on a polystyrene surface was highly strain-dependent, whereas the two non-O157 serotypes showed a higher potency of pellicle formation at air-liquid interfaces on a glass surface compared with serotype O157:H7. Significant reductions of viable biofilm cells were achieved with sanitizer treatments. STEC biofilm tolerance to sanitization was strain-dependent regardless of the serotypes. Curli expression appeared to play a critical role in STEC biofilm formation and tolerance to sanitizers. Our data indicated that multiple factors, including bacterial serotype and strain, surface materials, and other environmental conditions, could significantly affect STEC biofilm formation. The high potential for biofilm formation by various STEC serotypes, especially the strong potency of pellicle formation by the curli-positive non-O157 strains with high sanitization tolerance, might contribute to bacterial colonization on food contact surfaces, which may result in downstream product contamination.     

家具常用包装材料与结构

家具包装材料是实现家具正确包装的关键所在。重点阐述了家具包装容器和家具包装防护材料这两大类家具包装材料的类别和主要特性,以帮助家具企业更好的认知家具材料,从而实现正确的家具包装。     

烟包常用纸张的种类和特性

中国是世界上最大的烟草生产国,年产量达3445万大箱。这些香烟绝大部分都采用纸箱包装,纸张类型主要有白卡纸、白板纸、铜版纸和铝箔纸。如果全国按3400万大箱,软、硬盒包装各按50%计算,上述四个品种纸张的年销量为:白卡纸49万吨、白板纸30万吨、铜版纸6.8万吨、铝箔纸10.5万吨。近几年,硬盒包装发展势头强劲,因此,白卡纸的用量不断增长。而铝箔纸的广泛采用,更是表现了强烈的中国特色,不管是硬包还是软包,不管是一类、二类烟,还是低档次的四、五类烟,都采用华丽、高成本的铝箔纸。这一现象的发生,极大促进了中国铝箔纸生产企业的发展。这种…     

银耳多糖与大豆分离蛋白的相互作用及流变性能

研究银耳多糖(Tremella fuciformis polysaccharide,TFP)与大豆分离蛋白(soybean protein isolate,SPI)的相互作用,利用浊度、纳米粒度仪、激光共聚焦扫描显微镜、流变仪、荧光光谱法和傅里叶变换红外光谱法等对TFP与SPI的复合凝聚过程进行表征。结果表明：pH值、SPI与TFP质量比和盐离子浓度对凝聚体的形成影响较大,当SPI∶TFP>1时,与复合物形成相关的关键pH值(pH_c和pH_φ1)向高pH值方向移动。当SPI∶TFP<1时,pH_φ1向低pH值方向移动。随着体系中TFP比例的增大,浊度的最大吸收峰逐渐降低(pH_opt逐渐减小)。当SPI∶TFP=1∶1时,两者在pH 3.0处的相互作用最强,此时体系总体的黏度最大(约为1.30 Pa·s),形成的聚集体最多且粒径最大。NaCl浓度较低(<20 mmol/L)时能促进SPI-TFP凝聚体形成,NaCl浓度较高(≥20 mmol/L)时由于屏蔽作用会抑制凝聚体的形成。当剪切频...     

糖酯的表面活性及其在食品加工中的应用

糖酯是典型的非离子型生物表面活性剂.亲水-亲油平衡值、临界胶束浓度、乳化能力和乳化稳定性、起泡能力和起泡稳定性是表述糖酯表面活性的重要参数.为指导糖酯的合成和应用,阐述糖酯结构对上述性质的影响.糖酯可作为食品乳化剂、润湿与分散剂、食品质地改良剂、保鲜杀菌剂、结晶调节剂和抗老化剂,在食品加工中具有广泛用途.     

酒标签常用材料及应用介绍

近些年,随着社会的发展和人们生活水平的不断提高,标签被越来越广泛地应用于各种产品中.其中酒类产品更加离不开精美标签的衬托,甚至可以说,是否有一枚精美的标签也是决定酒类产品档次的标准之一.     

Kinetics of Water Uptake by Food Powders

The water uptake by several food materials that included animal and vegetable proteins and starch materials was studied. The amount q of water taken up by a sample powder during time t was described by the equation q = Qt/(B + t), where Q is the total water uptake of equilibrium and B is the time required to sorb Q/2. The rate of water uptake was proportional to the square of the amount of water that must still be absorbed to reach equilibrium. A specific rate constant for the process was calculated as (BQ)^?1.