淀粉和蛋白类添加物对鱿鱼鱼糜凝胶特性的影响

通过分析凝胶强度、白度、持水性等指标,研究淀粉类和非肌肉蛋白类添加剂对鱿鱼鱼糜凝胶特性的影响。结果表明,红薯淀粉、玉米淀粉、木薯淀粉和马铃薯淀粉均可提高鱿鱼鱼糜的凝胶强度,分别提高了49.08%,20.77%,26.46%,30.16%;4种淀粉均可提高持水性,其中红薯淀粉效果较好,为79.10%;添加淀粉后虽会导致白度有不同程度的降低,但差异不显著。非肌肉蛋白的添加使鱿鱼鱼糜组织结构更加紧密;除乳清蛋白外,大豆分离蛋白、大豆浓缩蛋白和蛋清蛋白均可提高鱿鱼鱼糜的凝胶强度,分别提高了39.03%,29.30%,35.82%。综合指标分析表明淀粉类及大部分蛋白质类添加物可以改善鱿鱼鱼糜的凝胶特性。     

碳酸钙与外源蛋白复配物对含有MTGase的鱼糜凝胶特性的促进作用

目的研究钙盐、外源蛋白及其复配物对含微生物产转谷氨酰胺酶(MTG)的鲢鱼糜凝胶品质的影响。方法将碳酸钙、乳酸钙、卵清蛋白、大豆分离蛋白及其复配物添加到含MTG(2 U/gg_(鱼蛋白))的鲢鱼糜中并制成凝胶,测定鱼糜凝胶的持水性、质构特性(破断强度、凹陷深度、硬度、内聚性、咀嚼性)、白度和聚丙烯酰胺凝胶电泳图谱。结果添加碳酸钙、乳酸钙、卵清蛋白、大豆分离蛋白及其复配物均可不同程度地改善含MTG的鱼糜凝胶的凝胶特性,且添加其复配物优于单独添加碳酸钙、乳酸钙、卵清蛋白、大豆分离蛋白。经试验优化,将8μmol/U_(MTG)碳酸钙、4 mg/U_(MTG)卵清蛋白、4 mg/U_(MTG)大豆分离蛋白添加到含有2 U/g_(鱼蛋白)MTG的鲢鱼糜中可获得最佳凝胶品质,鱼糜凝胶的破断力、凹陷深度最高,硬度、咀嚼性、白度均显著高于单独添加MTG(P0.05),也明显高于添加2 U/g_(鱼蛋白)其他品牌商品MTG的(P0.05)。结论 CaCO_3与外源蛋白复配物对含有MTG的鱼糜凝胶特性具有显著促进作用,将碳酸钙、卵清蛋白、大豆分离蛋白与MTG按比例混合可制成鱼糜制品专用的复配酶制剂。     

变性淀粉对白鲢鱼鱼糜凝胶特性和蛋白构象的影响

为了研究原木薯淀粉、羟丙基淀粉、乙酰化二淀粉磷酸酯和醋酸酯淀粉对白鲢鱼鱼糜凝胶特性和蛋白构象的影响,分析不同淀粉添加量条件下,白鲢鱼鱼糜白度、凝胶强度、持水性、质构特性、储能模量(G')、化学作用力、蛋白二级结构和微观结构的变化规律。结果表明,添加淀粉可以显著提高鱼糜凝胶的持水性。当其添加量为1%时,可提高鱼糜凝胶的白度、凝胶强度、硬度和咀嚼度,且羟丙基淀粉的改善效果最佳。流变学特性表明淀粉在鱼糜制品中起到非活性填料的作用。添加少量淀粉可阻碍氢键的形成,促进疏水相互作用及离子键的形成,诱导鱼糜蛋白的构象由α-螺旋结构向β-折叠结构转变。4种淀粉添加量为1%时均可以得到更为致密的鱼糜凝胶网络结构,其中,添加羟丙基淀粉可以使鱼糜凝胶网络中孔洞的大小、分布更均匀。添加1%的羟丙基淀粉可用于改善白鲢鱼鱼糜的凝胶品质。     

淀粉对高温杀菌鱼糜凝胶特性的影响

为提高杀菌鱼糜制品的品质,本文研究了添加不同浓度的木薯原淀粉和四种变性淀粉(羟丙基化二淀粉磷酸酯,乙酰化二淀粉己二酸酯,磷酸交联淀粉,羟丙基化淀粉)对120℃高温杀菌鱼糜凝胶特性的影响。通过测定分别添加5%,10%和20%淀粉后复合鱼糜凝胶的破断力,破断距离,凝胶强度,白度,持水率,曲折实验和扫描电镜等指标,研究不同淀粉对杀菌鱼糜凝胶质构性,色泽和持水能力的影响。结果表明各种淀粉适宜的添加量均为10%。在各种淀粉添加剂中,木薯羟丙基化二淀粉磷酸酯和木薯乙酰化二淀粉己二酸酯对高温杀菌后鱼糜凝胶的破断力,凹陷距离的改善效果最好,能显著增强鱼糜的凝胶强度(p0.05)。添加淀粉均会改善鱼糜凝胶的白度,使白度增加。添加木薯原淀粉,木薯乙酰化二淀粉己二酸酯和木薯羟丙基化二淀粉磷酸酯可不同程度提高鱼糜的持水力。     

大豆分离蛋白、木薯淀粉与转谷氨酰胺酶组合对鲢鱼鱼糜凝胶品质的影响

探究了大豆分离蛋白、木薯淀粉及转谷氨酰胺酶对鲢鱼鱼糜制品的影响并确定最适添加量。结果表明,当大豆分离蛋白添加量6%,木薯淀粉添加量9%以及转谷氨酰胺酶添加量4U/g·蛋白时,能有效增加鱼糜的持水性,降低其蒸煮损失,且不会使鱼糜带有大豆分离蛋白的淡黄色,同时提高了鱼糜的凝胶强度,鲢鱼鱼糜制品各项指标较好。通过低场核磁共振和扫描电镜检测发现,未添加的对照组在6次冻融后凝胶结构完全被破坏,不易移动水峰面积(A_(23))下降了25%,试验组凝胶结构比较致密,A_(23)下降了11%,进一步验证了此配方组合对鱼糜在冻融循环过程中凝胶结构的稳定性具有保护作用。     

不同种类淀粉对罗非鱼鱼糜凝胶品质的影响

为了改善淡水鱼鱼糜制品的品质,以冷冻罗非鱼鱼糜为原料,分别添加4%木薯原淀粉、3种木薯变性淀粉（磷酸酯淀粉、羟丙基淀粉和乙酰化二淀粉磷酸酯）及复配木薯变性淀粉（乙酰化二淀粉磷酸酯与羟丙基淀粉质量比为3∶2）,考察淀粉添加对鱼糜凝胶质构、流变学特性、持水性及水分分布和微观结构等的影响,探讨不同种类淀粉对鱼糜凝胶品质的改善。结果表明,与对照组相比,添加5种淀粉均会显著降低罗非鱼鱼糜凝胶的白度（P<0.05）,但其凝胶强度、硬度和咀嚼性显著增大,凝胶持水性显著提高（P<0.05）,蒸煮损失率显著下降（P<0.05）,结合水含量显著增加（P<0.05）,凝胶微观结构更加均匀致密,且添加了复配木薯变性淀粉的凝胶质构特性最好,持水性最高。低场核磁共振成像和光学显微镜观察结果显示,不同种类的淀粉均能有效锁住鱼糜凝胶基质中的水分;升温过程中淀粉吸水膨胀,在鱼糜凝胶网络结构中起浓缩和填充作用;添加了复配木薯变性淀粉的鱼糜凝胶结构最致密均匀。因此,添加复配木薯变性淀粉可以有效改善罗非鱼鱼糜制品的品质,为淡水鱼鱼糜制品的开发提供了理论支撑。     

磷酸盐和钙盐对罗非鱼鱼糜凝胶特性的影响

试验探讨2种钙盐(氯化钙和乳酸钙)和3种磷酸盐(三聚磷酸盐、焦磷酸盐和六偏磷酸盐)对罗非鱼鱼糜凝胶特性、持水率、白度以及折叠强度的影响。研究结果表明,不同添加量的氯化钙和乳酸钙都可以改善罗非鱼鱼糜的白度、持水率和鱼糜的折叠强度,添加0.3%的氯化钙对罗非鱼鱼糜可以显著提高罗非鱼鱼糜的凝胶强度,但不同添加量的乳酸钙对罗非鱼鱼糜的凝胶强度没有显著影响。不同添加量的3种磷酸盐均可提高罗非鱼鱼糜的白度、持水率以及鱼糜的折叠强度,这与钙盐的影响结果相同;当焦磷酸盐添加量低于0.2%,六偏磷酸盐添加量低于0.3%时,鱼糜的凝胶强度都得到显著性的提高(p0.05),而添加三聚磷酸盐则会降低罗非鱼鱼糜的凝胶强度。     

不同温度处理的大豆分离蛋白乳化大豆油对猪肉糜品质的影响

目的 探讨应用不同温度（20 ℃、60℃和98℃）处理的大豆分离蛋白乳化大豆油替代猪背膘生产低脂猪肉糜的可行性。方法 测量猪肉糜的色泽、质构、保水性、水分分布和移动性。结果 添加不同温度处理的大豆分离蛋白乳化大豆油显著提高（P < 0.05）猪肉糜的L*和b*值、蒸煮得率、硬度、弹性、内聚性和咀嚼性,降低水分移动性。大豆分离蛋白处理温度显著影响猪肉糜的品质,添加98℃处理大豆分离蛋白乳化大豆油的猪肉糜有最高的（P < 0.05）L*和b*值、蒸煮得率、质构特性和不易流动水的含量。结论 添加98℃处理大豆分离蛋白乳化大豆油的猪肉糜品质最佳。     

猪血浆蛋白对鲢鱼鱼糜品质的影响

将猪血浆蛋白添加到鲢鱼鱼糜制品中,测定鱼糜制品凝胶强度、TPA、失水率和色泽的变化,并采用化学方法研究了添加猪血浆蛋白后鱼糜的化学作用力和溶解率的变化。结果表明,以1.5g/100g比例添加猪血浆蛋白时,鱼糜凝胶强度较空白样品提高了约2倍,高于添加等量的大豆分离蛋白的鱼糜制品凝胶强度,失水率降低至4.29%,白度稍微降低。溶解率及化学作用力分析显示猪血浆蛋白主要是通过非二硫共价键(尤其是ε-(γ-Glu)-Lys)、疏水键及氢键来促进鱼糜形成更致密、均匀的三维网状空间结构。     

响应面法优化南美白对虾即食虾滑的加工工艺

为开发即食虾滑新产品,以南美白对虾为原料,研究不同辅料(金线鱼鱼糜、淀粉、大豆分离蛋白)添加量对虾滑凝胶强度、质构特性、持水性、白度和感官评分的影响。在单因素试验基础上,以感官评分和凝胶强度为响应值,利用响应面法对即食虾滑配方进行优化,结果表明:最适合添加到即食虾滑中的淀粉种类是木薯醋酸酯淀粉,影响即食虾滑产品品质的因素从高到低为金线鱼鱼糜添加量、大豆分离蛋白添加量、木薯醋酸酯淀粉添加量,最终得出即食虾滑的最优配方为:100 g虾仁,虾肉块、虾糜质量比3∶2,添加食盐1%、鸡蛋白粉0.3%、魔芋粉3%、金线鱼鱼糜12.68%、木薯醋酸酯淀粉3.30%、大豆分离蛋白1.14%、谷氨酰胺转胺酶0.3%、虾味剂0.4%、复合磷酸盐0.3%、饮用水8%,该条件下所得即食虾滑的口感爽滑、鲜味十足,感官评分和凝胶强度的综合评价结果最优,分别为90.50分和1 339.87 g·mm,与预测值相近,说明利用响应面法优化南美白对虾即食虾滑加工工艺的方法可靠、可行。     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

Tests of potential functional barriers for laminated multilayer food packages. Part II: Medium molecular weight permeants

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status