椰蓉膳食纤维对面包品质的影响

用椰蓉膳食纤维替代部分面粉进行面团发酵后制作面包,研究椰蓉膳食纤维对面团发酵体积及面包品质的影响。结果表明,添加椰蓉膳食纤维后,面团发酵体积较空白组有所减少,但在发酵后期两者的差异逐渐减少,120 min时添加1%的IDF和SDF面团体积分别为93.50 mL和102.25 mL,略低于空白面团的104.25 mL。另外,膳食纤维添加量1%时,面包的感官品质、质构特性和内部微观结构的改善效果最为明显,面包的柔软程度、口感和咀嚼性均有所提升。研究结果可为椰蓉的精深加工提供依据和参考。     

麦麸膳食纤维对面团流变学性质的影响

采用酶法制备了两种麦麸膳食纤维,即可溶性膳食纤维含量为1%的DF1和26.6%的DF2.用Brabender粉质仪和拉伸仪研究其对中筋面粉的面团流变学性质的影响.结果表明,麦麸膳食纤维对面团流变学性质的影响随着添加量和提取膳食纤维时酶水解方式的不同而不同;DF1和DF2对面团的粉质特性均有不同程度的改良作用,DF1的改良作用大于DF2;DF1的添加对面团的拉伸特性有恶化的作用,DF2对面团的拉伸特性则有一定的改良作用;DF1和DF2添加量分别为2%～4%和2%～10%时,对面团流变学性质有改良作用.     

高膳食纤维面团热机械学及面包的烘焙特性

研究大豆纤维粉(soybean dietary fibre,SDF)和玉米抗性淀粉(resistant starch,RS)及其混合物以20%、30%比例部分替代小麦粉在高膳食纤维面包中的应用,并分析高膳食纤维对面团热机械学特性及面包烘焙特性的影响。结果表明:SDF与RS的引入可提高面团持水性与吸水率(分别提高43.3%～63.3%和5%～7.6%),降低C5-C4值,对淀粉回生产生一定的抑制作用。两者对面团稳定时间和C1-C2的影响不同,RS会显著降低面团稳定时间(为对照组的53.52%～66.46%),增大C1-C2值24.14%～27.59%,蛋白质弱化度提高,而SDF对此则具有积极作用;通过对面包的烘焙特性分析发现,SDF与RS共用时具有协同作用,生产的面包不仅膳食纤维与蛋白质含量高,质构与风味较单独添加SDF有所改善,且提高了RS单独应用时的面包水分含量,提高得率。综合面包比容、色泽、质构与营养而言,5%SDF-15%RS和10%SDF-10%RS组制作的高膳食纤维面包品质最佳,且口感良好。     

红薯渣膳食纤维的制备及其对面包品质的影响

采用水提法和酶提法制备红薯渣膳食纤维,并比较了不同工艺制备的膳食纤维的含量及理化性质,研究了将其作为添加剂添加到面包中对面包品质的影响。结果显示：酶提法制备的膳食纤维纯度较水提法高,含量达到62．45％,其中SDF含量为2．52％,IDF含量为59．93％。以水提法制备的膳食纤维代替5％面粉。加水量为57％时面包的品质最佳;以酶提法制备的膳食纤维代替5％面粉,加水量为72％时,面包的品质最佳。     

天然菊粉对面团流变学及面条品质的影响

为了获得膳食纤维含量高的面条,探讨了天然菊粉对面粉糊化、面团流变学和面条品质的影响。结果表明,天然菊粉能够显著(p<0.05)降低面粉糊化过程中的峰值黏度、峰谷黏度、最终黏度和破损值,显著提高糊化温度(p<0.05)。天然菊粉能够改善面条面粉的粉质和拉伸特性。添加天然菊粉能使面团吸水率和弱化度降低,而使面团的形成时间、稳定时间和粉质质量指数增加。随天然菊粉添加量的增加,面团的拉伸阻力和拉伸比例逐渐增大,而拉伸曲线面积和延伸度呈先增大后减小的趋势。当天然菊粉添加量为7.5%时,面条的干物质吸水率高达180.66%。在天然菊粉1.25%~15%添加量实验范围内,天然菊粉的添加对面条的弹性和咀嚼性没有显著影响(p>0.05)。综合考虑,天然菊粉的最适添加量为7.5%。     

乳化剂影响新鲜及冷冻面团面包品质的研究

研究了硬酯酰乳酸钠(SSL)、卵磷脂、单甘酯、蔗糖酯、双乙酰酒石酸甘油酯(DATEM)等几种面包加工常用乳化剂对新鲜面团及冷冻面团的力学特性及面包的质构和感官品质的影响。结果表明,乳化剂的添加会显著提高新鲜面团的力学特性和新鲜面团面包的感官品质,卵磷脂为最适乳化剂,适宜添加量为0.45%(面粉为基数);乳化剂对冷冻面团的力学特性的影响不显著,但可以显著改善冷冻面团面包感官品质,SSL为最适乳化剂,适宜添加量为0.30%(面粉为基数)。     

膳食纤维对面粉品质影响的研究

以小麦纤维、燕麦纤维、抗性糊精和菊粉作为膳食纤维的来源,考察了其不同添加量对面粉面筋质、粉质特性、糊化特性及动态流变学特性的影响。结果表明小麦纤维、抗性糊精和菊粉降低了面粉湿面筋含量,添加燕麦纤维则提高了湿面筋含量,高添加量(10%)时面粉的面筋指数均能恢复至对照样水平,甚至更高。四种膳食纤维均能提高面粉的粉质稳定时间和粉质质量指数,降低粉质弱化度,提升了面团的耐搅拌性和筋力强度。动态流变学特性显示添加四种膳食纤维均提高了面团的G"和G"",说明面团的强度增加。但不同膳食纤维存在差异,小麦纤维、燕麦纤维和菊粉能提高面团的G"和降低tanδ,说明提高了面团的弹性和固体性质,添加抗性糊精则提高了面团的G"和tanδ,说明相对提高了面团的延展性。添加四种膳食纤维均能降低面糊的峰值粘度、崩解值和回生值,有助于面糊的热稳定和延缓其回生。     

大豆种皮膳食纤维的生物发酵与酶解法制备及其体外降脂的研究

为探究不同提取方法对大豆种皮膳食纤维(Dietary fiber, DF)的理化性质的影响,对比分析了发酵法和复合酶法提取的大豆种皮膳食纤维的理化性质及其体外降血脂功能。米曲霉发酵大豆种皮的可溶性膳食纤维的(Soluble dietary fiber, SDF)提取率为9.18%,不溶性膳食纤维(Insoluble dietary fiber, IDF)的提取率为86.31%;复合酶法的SDF的提取率为12.24%, IDF的提取率为72.18%。两种方法制备的SDF的持水性、溶胀性、持油性均高于IDF;当DF膳食纤维的添加量为1 g时,发酵法制备的SDF对胆酸盐的结合率达到最大70.28%;在0～90 min时,各组分的胆固醇吸附量均随吸附时间的延长呈上升趋势,且发酵法SDF的吸附能力最好;DF在pH=7时的胆固醇结合率高于pH=2时的结合率,两种方法制备的DF整体效果均为SDFIDF。     

米糠膳食纤维与食盐对面粉粉质及糊化特性的影响

为了给研发高品质米糠膳食纤维面制品提供理论依据,本文用微型粉质仪和快速粘度分析仪研究了米糠膳食纤维与食盐各自及共同对面粉粉质及糊化特性的影响规律。研究结果表明:添加米糠膳食纤维使面团弱化度最高增大48%,使面粉糊化温度最大增高26%,使面粉糊化的峰值粘度最高下降23%、最终粘度最高下降21%、衰减值最高减少13%、回生值最高减少8%;添加食盐使面团的形成时间最高延长79%、稳定时间最高延长277%、弱化度最高减少52%,使面粉糊化的衰减值最高增大12%、回生值最高减少12%;添加2%食盐使米糠膳食纤维对面团弱化度的增大作用降低为0,对面粉糊化温度的最大提高作用小于2.5%,对面粉糊化峰值粘度的下降作用减少5%,对面粉糊化回生值的减小作用提高到12%。     

豌豆苗膳食纤维的添加对面团和面包物性的影响

将粗提取的豌豆苗膳食纤维添加到面粉中制作面团,结果发现,随添加量的不断增大,面团的黏度逐渐增大,回复性有所降低.但弹性和咀嚼性无明显变化.添加豌豆苗膳食纤维对面包的体积膨胀有抑制作用,同时使面包皮的硬度和脆性降低,面包心的硬度在一定加入量范围内也降低.贮藏实验表明,添加豌豆苗膳食纤维(<15%)对防止面包的老化有积极意义.该研究为今后膳食纤维在面制品中的强化应用提供了实验依据.     

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