双酶法提取星鳗骨鱼油的工艺研究

以星鳗骨为原料,研究了双酶法提取星鳗骨鱼油的工艺条件。在单因素试验的基础上,以鱼油得率为指标进行响应面优化试验,并对星鳗骨鱼油进行理化性质分析。结果表明,最佳的提取条件为:每100 g底物中加入1.6 g胰蛋白酶,加1.6%胰蛋白酶,在酶解温度45℃、初始p H 8下水解4.2 h;再加入1.0%胃蛋白酶,调节p H 2.5,控制酶解温度为40℃,在此条件下酶解3.1 h,最终的粗鱼油得率达到24.44%。所得星鳗骨鱼油颜色为浅黄色,具有鱼油腥味,但是没有明显鱼油的酸败味,指标符合SC/T 3502—2016鱼油中粗鱼油二级标准。     

脂肪酶水解低值鱼油富集EPA和DHA甘油酯的研究

以从南海盛产低值鱼蛇鲻中提取的鱼油为原料,采用脂肪酶选择性水解法富集鱼油中EPA和DHA,研究结果表明在pH 7的缓冲溶液反应体系中,按照水油质量比4:1加入鱼油,脂肪酶OF添加量为1%,然后充氮气密封,在40℃的恒温水浴中震荡反应16 h后,鱼油中的EPA和DHA总含量达到了34.1%;水解后鱼油的组分主要以甘油二酯为主,含量为63.3%;其次是甘油三酯和甘油一酯,含量分别为34.3%和2.4%.     

竹荚鱼加工废弃物中鱼油的分离提取

以竹荚鱼(Trachurus)加工废弃物为原料,采用了蒸煮法和胰蛋白酶酶解法两种工艺提取鱼油,分别以提取率和感官特征等指标对两种提取工艺的参数进行考察优化,得到最佳的提取条件.结果显示:蒸煮法的最佳条件为:蒸煮温度95℃,蒸煮时间40min;胰蛋白酶酶解法的最佳条件为:酶解温度40℃,酶添加量1.5%,料液质量比1:1.5,酶解时间4h.通过比较提取率、感官、理化性质,确定选取蒸煮法分离提取竹荚鱼加工废弃物鱼油.     

水合法提取罗非鱼鱼油及其脂肪酸组成分析

以冻干的罗非鱼粉为原料,采用酶解法和稀碱水解法分别提取罗非鱼鱼油,通过单因素试验和正交试验,确定两种水合法的最佳工艺条件,并采用气相色谱法分析罗非鱼鱼油脂肪酸组成。结果表明:稀碱水解法提取罗非鱼鱼油最佳工艺条件为料液比1∶3、pH 7.5、水解时间30 min、盐析量2.5%、盐析时间25 min、水解温度65℃;酶解法提取罗非鱼鱼油最佳工艺条件为料液比1∶3、加酶量0.6%、pH 9、酶解温度55℃、酶解时间2 h;在最佳工艺条件下,稀碱水解法的提油率为(32.13±0.07)%,略高于酶解法的(28.91±0.18)%;稀碱水解法提取罗非鱼鱼油n-3不饱和脂肪酸含量为(5.192±0.280)%,高于酶解法的(4.991±0.099)%。     

鳀鱼油皂脚的酸化工艺优化

采用响应面实验对鳀鱼油皂脚的酸化工艺进行了优化,并对得到的高酸值粗鱼油进行了脂肪酸分析。结果表明:当皂脚酸化的工艺条件为:H2SO4用量4.18 mL/100 g、反应时间60 min、反应温度71℃、料液比3∶7(g∶mL),皂的转化率高达99.92%;粗鱼油中共检出26种脂肪酸,其中不饱和脂肪酸占51.69%,饱和脂肪酸占37.18%,必需脂肪酸占2.78%,EPA和DHA占21.89%。     

鲈鱼油的酶解提取工艺研究及理化指标分析

研究以海南海鲈鱼腹腔脂肪为原材料,采用酶解法从中提取鱼油,测定鱼油的理化指标。首先以鱼油得率为评价指标,研究不同种蛋白酶、温度、液固比、加酶量和pH五个因素对鱼油得率的影响,并通过正交试验设计获得提取鱼油的最佳酶解工艺条件:采用胰蛋白酶,酶解温度37℃,酶解时间3 h,液固比3:1(mL/g),加酶量0.25%,pH7.8。利用此工艺条件,鱼油得率最高。并对最佳工艺进行验证试验,鱼油得率均值为72.5%,RSD为1.5%,说明工艺稳定。通过对理化指标的测定,粗鱼油符合一级国家标准。     

水酶法提取鲢鱼内脏油脂的工艺研究

采用水酶法从鲢鱼内脏中提取淡水鱼油。选用Alcalase做为酶解所用酶,研究液固比(W/F)、加酶量、酶解时间、pH、温度5个因素对鱼油得率的影响。结果表明:当温度为60℃,用酶量为1.0%(E/S),液固比(W/F)为1∶1,pH为8,酶解3.5h时鲢鱼内脏鱼油的得率达到92.36%,远远高于淡碱法提取的鱼油得率68.50%。     

胰蛋白酶法提取草鱼内脏鱼油工艺优化

利用胰蛋白酶酶解法从草鱼内脏中提取鱼油。以鱼油提取率为指标,利用响应面分析法,研究酶解条件对鱼油提取率的影响。结果表明:利用胰蛋白酶提取草鱼内脏鱼油的酶解工艺参数为酶解温度48℃、酶解pH8、酶添加量1.65%、料液比1:0.87(m/m)、酶解时间4h。在此条件下,实际测得鱼油提取率为70.16%。     

双酶酶解金枪鱼加工下脚料提油工艺

以金枪鱼加工下脚料为原料,对双酶酶解法提取粗鱼油进行研究,主要考察了料液比、蛋白酶A、B添加量、反应时间以及破乳条件对粗鱼油提取率的影响。优化的工艺条件为料液比1:3,蛋白酶A、B添加量均为1.5%,反应时间各为3、2h,所得酶解液在-20℃冻结12h与40℃解冻1.5h进行破乳。在该条件下粗鱼油提取率为(6.58±0.56)%,理化指标均达到SC/T3502—2000的粗鱼油二级标准。     

鳀鱼自溶水解过程的生化变化

鳀鱼含有丰富的蛋白质和内源蛋白酶类,具有较高的开发利用价值。在室温(26℃)和不同初始pH条件下,对鳀鱼自溶水解过程中的生化变化规律进行研究。结果表明,在室温(26℃)条件下,鳀鱼自溶水解的最佳时间为12h;在初始pH9.0的条件下,自溶水解液中的α-氨基氮含量、可溶性总氮含量、蛋白质回收率和氨基氮转化率均较高,分别达到(0.3904±0.0145)g/100mL、(1.3109±0.0181)g/100mL、(55.9±1.19)%、(29.78±0.62)%。因此,鳀鱼的自溶水解过程可完成鳀鱼自身蛋白的部分水解,自溶水解可作为鳀鱼加工处理的一个生产环节。     

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.