酶法提取生姜精油的研究

为了优化生姜精油的提取工艺,采用纤维素酶作用于生姜提取生姜精油,探讨酶解时间、酶解温度、酶解pH和酶用量对生姜精油提取率的影响.结果表明,纤维素酶作用能显著提高生姜精油的提取率,鉴于各影响因子之间的相互作用,在单因素试验的基础上,设计了正交试验,分析试验结果,得出最合适的工艺参数为酶解温度46 ℃、酶解时间2 h、pH 6.0、纤维素酶用量2.2%,生姜精油得率达到0.39%.酶法提取生姜精油是一种合适的提取生姜精油的方法.     

超临界CO2萃取生姜油工艺优化研究

采用超临界CO2萃取方法,研究从生姜中提取生姜油的最佳生产工艺,着重探讨粉碎度、萃取压力、萃取温度、萃取时间、C02流量等参数对出油率的影响,并应用正交试验探讨优化工艺参数.研究结果表明:采用萃取压力30MPa,萃取温度45℃,萃取时间2.5h,C02流量380kg/h等工艺条件,可使干生姜粉的出油率达1.81%.     

生姜抑制亚硝化反应有效成分的提取工艺研究

以生姜为原料,亚硝酸盐清除率和亚硝胺合成阻断率为评价指标,优化生姜中清除亚硝酸盐和阻断亚硝胺合成的有效成分提取工艺,研究结果表明:超声辅助提取效果最好,最佳工艺参数料液比1︰5 (g/mL)、超声功率171W及超声时间为30 min,此条件下得到生姜提取物亚硝酸盐清除率和亚硝胺抑制率分别为45.81%和24.56%。     

模糊数学模型优化姜露饮品的口味

以生姜为主要原料,并以冰糖、红枣干、柠檬酸、枸杞和桂花为辅料制备生姜露保健饮品。在三元二次回归模型设计优化生姜露饮品口味的基础上,结合模糊数学模型综合评价最优工艺参数并进行验证。结果表明在生姜质量分数为11.50%,红枣干质量分数为8.00%、柠檬酸质量分数为0.28%,熬煮15 min制备生姜露感官评分最高,口感最佳,且具有明显的姜辣味和淡淡的花香味,产品均匀澄清无杂质。     

超临界CO_2萃取生姜油的模型方程和条件优化

优化超临界CO2萃取生姜油的工艺条件,提高生姜油的萃取率.以生姜油萃取率为响应值,利用单因素试验、正交试验、回归分析和响应面分析法对超临界CO2萃取生姜油的工艺条件进行系统研究.建立对萃取率可以进行较好预测的数学模型方程,证明影响萃取率的各主要因素间存在不同大小的交互作用,得到了生姜油超临界CO2萃取的最佳工艺条件:萃取压力29MPa;萃取温度50℃;萃取时间180min;解析压力5.6MPa;解析温度36℃.最佳工艺条件下生姜油萃取率为:7.461%.     

超临界萃取结合分子蒸馏纯化生姜精油及其挥发性成分分析

为研究超临界萃取结合分子蒸馏纯化生姜精油的最佳工艺参数,鉴定生姜精油的挥发性成分,以舒城黄姜为原料,通过单因素试验和正交试验优化了超临界CO₂流体萃取(supercritical CO₂ fluid extraction, SFE)生姜油的最佳工艺条件,考察了分子蒸馏(molecular distillation, MD)温度对分离纯化生姜精油效果的影响,并通过气相色谱-质谱联用对生姜精油的挥发性成分进行了分析。结果表明,超临界CO₂流体萃取结合分子蒸馏(SFE-MD)纯化生姜精油的最佳工艺条件为萃取压力24 MPa、萃取温度45℃、萃取时间2 h、分子蒸馏温度80℃,在此条件下,生姜精油的综合得率为2.53%,显著高于水蒸气蒸馏精油得率0.96%(P<0.05)。挥发性成分分析显示,α-姜烯、β-倍半水芹烯、β-红没药烯是生姜精油的主要挥发性成分,百分含量达70%以上,其中α-姜烯百分含量为42.13%,高于水蒸气蒸馏生姜精油α-姜烯百分含量40.59%。该方法绿色环保,萃取率高,精油品质好,为生姜精油的进一步研...     

红糖姜片真空渗糖工艺参数的探讨

探讨红糖姜片真空渗糖工艺参数.方法:以生姜、红糖为主要原料,对真空渗糖工艺中真空度、渗糖时间、梯度、温度等条件进行研究,测定其总糖、水分的含量.结果表明:最佳真空渗糖工艺条件为真空度-0.09 MPa,温度40 ℃,渗糖梯度为先用60%的红糖液后用90%的红糖液,时间均为6 h.该工艺得到的红糖姜片含糖量为65.22%,含水量为18.6%,且饱满、柔韧、有光泽.     

超声结合酶法提取生姜中水溶性膳食纤维及其功能性研究

以生姜为原料,采用超声水提法和超声结合酶法提取生姜中水溶性膳食纤维,探讨料液比、超声时间、超声功率、加酶量等对提取率的影响,通过正交试验优化工艺条件,并对其功能性进行研究。结果表明,超声水提取最佳工艺条件为料液比1:30、超声时间25min、超声功率100W,生姜中水溶性膳食纤维提取率最高为10.02%;超声结合酶法提取最佳工艺条件为加酶量3%、料液比1:25、超声时间25min、超声功率100W,生姜中水溶性膳食纤维提取率为13.86%,比超声水提法提取率提高了38.2%。生姜中水溶性膳食纤维对.OH和O-2.均表现出较强的清除能力,其IC50分别为2.58mg/mL和0.42mg/mL,对DPPH自由基具有一定的清除作用,清除率可达40%以上;生姜中水溶性膳食纤维的持水力为359%,膨胀力为2.86mL/g。     

响应面优化生姜多糖提取工艺及其抗氧化活性研究

采用Box-Benhnken法优化生姜多糖的提取工艺参数,分别考察提取时间、提取温度及液固比对多糖得率的影响,采用三因素三水平响应面法进行多糖提取工艺的优化,利用傅立叶红外光谱分析其结构。结果表明,生姜多糖最佳提取时间为2 h 44 min,提取温度为71.6℃,液固比为41∶1(m L/g),在此条件下,生姜多糖得率为3.13%。后经抗氧化活性测定,生姜多糖提取物具有一定抗氧化活性。     

利用超临界流体萃取制备生姜油工艺技术的研究

本文介绍了超临界CO_2萃取生姜中挥发性油的提取分离技术工艺,重点研究了超临界CO_2萃取压力、温度、时间对出油率的影响,并且应用正交实验优化出较佳的工艺参数:SC-CO_2萃取压力为:25MPa;温度为:45℃;时间为:120min;流量为:25L/min由超临界CO_2萃取干生姜粉挥发油的出油率高达4.27%。     

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.