啤酒废酵母自溶条件的研究

啤酒废酵母的自溶条件包括自溶时间、自溶促进剂、pH值、自溶加水量、自溶温度等。试验结果表明，啤酒废酵母的最佳自溶条件为：自溶时间48h，促进剂食盐，浓度为3％，pH值为7，加水量250％，温度50℃，添加木瓜蛋白酶将促进酵母自溶，浓度0.03%，自溶时间可缩短到24h。（一平）     

啤酒废酵母自溶条件的研究

本文探讨了以啤酒废酵母为原料，采用自溶法生产酵母抽提物的条件。结果表明：以食盐为啤酒酵母自溶促进荆的最佳作用条件是10％的啤酒酵母悬浮液在pH5．0、温度50℃、食盐浓度3％T，自溶40h，所得酵母抽提液的氨基氮含量为O．498g／100mL．产品得率47．50％。风味非常醇厚。     

从啤酒废酵母制取氨基酸工艺的研究

目的研究以啤酒废酵母为原料生产氨基酸的工艺条件。方法研究温度、pH、食盐浓度、木瓜蛋白酶添加量、自溶(水解)时间等因素对啤酒废酵母水解的影响,确定最佳自溶条件。结果啤酒废酵母最适自溶(水解)条件为:温度55℃,pH5.5,食盐浓度3%,木瓜蛋白酶添加量0.8%(以啤酒废酵母干重计,自溶16 h后开始添加),自溶(水解)时间28 h。结论确定了利用啤酒废酵母生产氨基酸的最佳自溶(水解)条件。     

利用啤酒废酵母开发功能性液态调味剂的研究

为了得到利用啤酒废酵母生产功能性调味剂的最佳工艺流程;试验在前期啤酒废酵母的脱苦工艺和自溶条件单因素研究的基础上,对啤酒废酵母的自溶条件进行正交试验,并对功能调味剂的调配进行正交试验;结果表明:废酵母自溶的最佳自溶条件为pH 7.0、自溶温度55℃、自溶时间60h,影响因素依次为自溶时间>pH>自溶温度;功能性调味剂最优调配组合为糖1%、酒精2%、酱色1%,对调味剂风味的影响因素依次为:酒精>酱色>糖。     

从啤酒废酵母制取氨基酸工艺的研究

目的研究以啤酒废酵母为原料生产氨基酸的工艺条件。方法研究温度、PH、食盐浓度、木瓜蛋白酶添加量、自溶（水解）时间等因素对啤酒废酵母水解的影响,确定最佳自溶条件。结果啤酒废酵母最适自溶（水解）条件为：温度贷℃,pH5．5,食盐浓度3％,木瓜蛋白酶添加量0．8％（以啤酒废酵母干重计,自溶16h后开始添加）,自溶（水解）时间28h。结论确定了利用啤酒废酵母生产氨基酸的最佳自溶（水解）条件。     

以产朊假丝酵母为原料生产风味酵母抽提物工艺的研究

以产朊假丝酵母为原料制备酵母抽提物,以氨基态氮含量和抽提物得率为主要指标考察了对酵母自溶影响关键的几个因素,包括均质压力、均质次数、自溶温度、自溶p H、外加蛋白酶的种类及添加量、自溶时间,并在此单因素实验基础上对酵母自溶进行正交实验,最后确定了酵母抽提物的最佳工艺条件为:15%浓度的酵母悬浮液,75MPa压力下循环均质2次后,调初始p H6.5,并添加1.5%(w/w)的复合风味酶,温度50℃下水浴自溶48h。在此最佳工艺条件下,制得的酵母抽提物的氨基态氮含量和得率分别达到650.6mg/100m L和50.1%,该酵母抽提物有酱香并略带酯香,口感浓郁有鲜甜味。     

啤酒废酵母自溶条件的研究

探讨了以啤酒废酵母为原料,采用自溶法生产酵母抽提物的条件。结果表明:以食盐为啤酒酵母自溶促进剂的最佳作用条件是10%的啤酒酵母悬浮液在pH5·0、温度50℃、食盐浓度3%下,自溶40h,所得酵母抽提液的氨基氮含量为0·498g/100mL,产品得率47·50%,风味非常醇厚。     

利用活性干酵母制备酵母抽提物的工艺研究

以活性干酵母为原料,采用自溶-酶联技术制备酵母抽提物。以氨基氮得率和抽提物得率为主要指标考察了对酵母自溶影响关键的几个因素,包括自溶温度、酵母悬浮液浓度、自溶pH值、外加破壁酶的种类、外加蛋白酶的种类及添加量、自溶促进剂,并在此基础上对酵母酶联自溶进行正交试验,最后确定了酵母酶联自溶的时间。结果表明:自溶-酶联技术是制备酵母抽提物的理想方法,在最佳工艺条件下制得的酵母抽提物氨基氮得率和抽提物得率分别达到3.19%和51.31%。     

基于功能性调味剂开发的啤酒废酵母自溶工艺条件的研究

为了设计利用啤酒废酵母生产功能性调味剂的工艺流程,试验对啤酒废酵母的脱苦工艺和自溶条件进行研究。结果表明:啤酒废酵母脱苦的最佳NaHCO3浓度为0.5%,最佳的自溶条件为0.3%NaCl溶液和0.05%的溶壁酶作促进剂、pH7.0、自溶温度55℃、自溶时间60 h。     

啤酒废酵母甘露聚糖的制备

本实验以啤酒废酵母为原料,研究了自溶法制备甘露聚糖的最佳工艺条件,并将优化后的自溶法和常用的酸碱法进行了比较,最后对最佳自溶条件在5L 发酵罐中进行了放大实验。结果表明：自溶24h 后,酵母残渣中的甘露聚糖含量达到最高值;制备啤酒废酵母细胞壁的最佳自溶条件为温度50℃、NaCl 2%、pH6,此条件下,酵母自溶残渣中甘露聚糖含量达到164.95mg/g,优于传统的酸法、碱法;自溶因素的重要性次序为：温度＞ NaCl浓度＞ pH 值。放大实验结果表明,最优自溶条件下甘露聚糖含量达到149.00mg/g。     

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.