酶法提高芋头浆中淀粉水解率的工艺条件研究

针对芋头浆中被粘多糖蛋白质和果胶等粘性物质包裹的淀粉难以水解的难题,研究采用复合纤维素酶-果胶酶和中性蛋白酶分步酶解法对芋头浆进行前处理,以提高α-淀粉酶酶解芋头浆淀粉的水解率。通过单因素实验和正交实验优化,结果表明,复合纤维素酶-果胶酶酶解最佳条件为:添加量0.2%,酶配比1∶1,pH5.8,酶解时间40min;中性蛋白酶酶解最佳条件为:添加量0.8%,pH7.3,酶解温度48℃,作用时间7.0h,该条件下,芋头浆出汁率和蛋白质水解率分别达到74.67%和40.46%。对经上述酶法预处理后的芋头浆中的淀粉进行酶水解,其水解率高达87.39%,与芋头原浆直接酶解相比提高了33.07%。     

酶解鲽鱼下脚料的工艺优化

以鲽鱼下脚料为原料,采用不同蛋白酶对鲽鱼下脚料进行酶解。以水解度作为评价指标,比较不同蛋白酶的水解能力,筛选最佳酶,并对其水解工艺进行优化。结果表明:对鲽鱼下脚料水解效果较好的是中性蛋白酶和风味蛋白酶,中性蛋白酶水解鲽鱼下脚料的优化条件为:酶用量0.1%,pH值6.0,温度50℃,酶解时间4.5 h。风味蛋白酶水解鲽鱼下脚料的优化条件为:酶用量0.05%,pH值6.0,温度50℃,酶解时间5.0 h。二者复合的工艺条件为:中性蛋白酶/风味蛋白酶=2/1(添加量为0.15%),pH6.0、酶解时间4.5 h,温度50℃,在此条件下水解度可达44.56%。     

贻贝油膏多酶协同水解工艺研究

采用酸性蛋白酶、中性蛋白酶和碱性蛋白酶对贻贝油膏生产中的酶解条件进行研究。探讨了酶解温度、酶解时间、酶添加量和酶解pH对原料水解度的影响。结果表明:酸性蛋白酶的最适作用条件为温度55℃、时间2h、添加量2.5%、pH 2.5;中性蛋白酶为温度50℃、时间3h、添加量2.5%、pH 7.5;碱性蛋白酶为温度50℃、时间3h、添加量1.5%、pH 8.5。原料经三种酶协同水解后,水解度可以达到71.7%。     

中性蛋白酶-超声波处理降低大米淀粉中蛋白质的残留

采用中性蛋白酶结合超声波法分离大米淀粉和蛋白质,研究采用诺维信公司的中性蛋白酶neutrase1.5MG水解米粉,pH值是高度显著影响因素,而酶解温度和酶解时间是显著影响因素,采用正交回归分析得到最佳工艺条件为:加酶量为0.1%,液固比为9∶1,酶解时间为2.43h,即145.8min;酶解pH值为7.48;酶解温度51.95℃。对酶解后进行超声波作用可以更好的降低淀粉中的残留蛋白质,最终残留蛋白质2.45%,淀粉回收率73.72%。     

虾加工副产品中虾油提取工艺研究

通过比较碱性蛋白酶、中性蛋白酶、风味蛋白酶、复合蛋白酶和胰蛋白酶对虾加工副产品的酶解,确定风味蛋白酶作为最佳水解酶,并确定其起始pH值为6．5,考察了酶添加量、料液比、酶解时间和温度对虾油提取率的影响,确定最优工艺：酶添加量1．0g／100g,料液比1g：8mL,酶解时间2．5h,酶解温度50℃。     

酶解乳蛋白制取乳源肽的研究

用酸性蛋白酶、中性蛋白酶和碱性蛋白酶对牛乳蛋白进行水解，研究了水解工艺，并通过正交试验对工艺进行了优化。结果为：酸性蛋白酶水解牛乳蛋白的最佳工艺条件是：水解温度50℃，时间120min，pH值3．0，加酶量8．0％；中性蛋白酶水解温度50℃，时间90min，pH值7．0，加酶量1．60％；碱性蛋白酶水解温度60℃，时间105min，pH值9．0，加酶量8．0％。中性蛋白酶水解物苦昧最小，最适宜作食品。     

响应面法优化高粱米淀粉的中性蛋白酶法提取工艺

以高粱米为原料,以淀粉回收率为指标,通过单因素及响应面优化试验,对高粱米淀粉的中性蛋白酶法提取工艺进行了优化。结果表明,中性蛋白酶法提取高粱米淀粉的最佳工艺条件为,中性蛋白酶添加量600 U/g,酶处理温度35℃,酶处理p H 7.0,酶处理时间3.2 h,粉碎粒径132μm。在此条件下,高粱米淀粉回收率为83.35%,与普通水提法相比增加了16.49%,具有较高的应用价值。     

水酶法提取花生水解蛋白的研究

采用水酶法从冷榨花生饼中提取水解蛋白。以溶出的蛋白质浓度为指标,研究了提取花生蛋白的酶解工艺及条件。结果表明,先用碱性蛋白酶水解再用中性蛋白酶水解效果优于单一酶,碱性蛋白酶最适条件为：温度为55℃,pH值为9．0,加酶量为0．8％,水解时间为3h;中性蛋白酶最适条件为：温度为50℃,pH值为6．5,加酶量为0．3％,水解时间为1．5h。此条件下,蛋白提取率可达90．29％。     

水酶法提取花生水解蛋白的研究

采用水酶法从冷榨花生饼中提取水解蛋白。以溶出的蛋白质浓度为指标,研究了提取花生蛋白的酶解工艺及条件。结果表明,先用碱性蛋白酶水解再用中性蛋白酶水解效果优于单一酶,碱性蛋白酶最适条件为：温度为55℃,pH值为9．0,加酶量为0．8％,水解时间为3h;中性蛋白酶最适条件为：温度为50℃,pH值为6．5,加酶量为0．3％,水解时间为1．5h。此条件下,蛋白提取率可达90．29％。     

酶法水解牛胎盘下脚料

以牛胎盘下脚料为原料，试验5种蛋白酶对其进行水解，根据水解液综合效果确定中性蛋白酶为最适单酶，其最佳水解条件为温度40℃，pH7．5，酶添加量4000u／g，料水比1：3，水解时间4h；响应面分析方法知，中性蛋白酶与胰蛋白酶混合水解牛胎盘下脚料的最佳水解条件为：温度46．4℃，pH值为8．17，酶比1：1(酶量为4000u／g)，料水比为1：3。氨基酸分析结果表明：混合酶水解液的游离氨基酸2483.6mg／L，而中性酶水解液的游离氨基酸493.8mg／L。     

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.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.