柠檬醛纳米乳液对鲅鱼鱼糜凝胶品质及贮藏稳定性的影响

目的 为了改善鱼糜制品的品质及其贮藏稳定性,添加不同浓度柠檬醛纳米乳液（0.35%-0.55%,添加量为3%）制备鲅鱼鱼糜。方法 测定鱼糜的凝胶性能、微观结构、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、氧化稳定性以及菌落总数。结果 柠檬醛纳米乳液的添加提高新鲜鲅鱼鱼糜的凝胶强度、持水性以及质构特性 (P < 0.05),降低蒸煮损失率 (P < 0.05),且凝胶网络结构致密有序,孔洞较小,表面光滑。当柠檬醛纳米乳液浓度为0.45%时,新鲜鱼糜凝胶品质最好。此外,在贮藏过程中,各处理组鱼糜的持水性、蒸煮损失、氧化稳定性、TVB-N值和菌落总数均优于对照组,表现最佳为0.45%组。结论 柠檬醛纳米乳液的加入能够提高鲅鱼鱼糜的凝胶性能,增强鱼糜在贮藏过程中的氧化稳定性,抑制鱼糜中微生物的生长,为进一步鱼糜凝胶品质的改善提供参考。     

糖基化凝胶增强剂对鱼糜制品凝胶特性的影响

以新鲜蛋清、刺槐豆胶和瓜尔豆胶为原料,采用湿法糖基化法制备凝胶增强剂,并加入到冷冻鱼糜中,研究糖基化凝胶增强剂对红娘鱼鱼糜制品的凝胶强度、质构、白度、持水性和化学作用力等的影响。结果表明,凝胶增强剂经湿法糖基化改性后可显著提高鱼糜制品的凝胶强度（P＜0.05）。最佳改性条件为反应温度55?℃、加热时间12?h。在此条件下,凝胶增强剂接枝度为（23.37±1.62）%,十二烷基硫酸钠-聚丙烯酰氨凝胶电泳显示蛋白聚集体的形成,表明蛋清蛋白与刺槐豆胶和瓜尔豆胶复配胶显著发生糖基化反应,添加到冷冻鱼糜中可明显改善鱼糜制品的凝胶强度、白度和持水力等。与未添加凝胶增强剂的鱼糜制品相比,凝胶强度提高64%;与添加同等含量的新鲜蛋清的鱼糜制品相比,凝胶强度提高26.9%;与添加未发生糖基化反应的凝胶增强剂的鱼糜制品相比,凝胶强度提高4.7%。实验表明,糖基化改性后的凝胶增强剂具有显著提高鱼糜制品凝胶特性的作用,在鱼糜产业中具有广阔的应用前景。     

外源添加物对鲢鱼-鳕鱼复合鱼糜凝胶性能的影响

以鲢鱼与鳕鱼为主要原料,选择外源添加物马铃薯淀粉、谷氨酰胺转氨酶（Glutamine transaminase, TGase）以及蛋清蛋白的添加量为单因素,以复合鱼糜凝胶强度为响应值,采用Box-Behnken响应面试验优化复合鱼糜凝胶性能,并用质构性能分析和扫描电镜对最优复合鱼糜凝胶性能进行验证。结果表明:鲢鱼-鳕鱼复合鱼糜在马铃薯淀粉添加量为16%,谷氨酰胺转氨酶（TGase）添加量为0.4%,蛋清蛋白添加量为6.0%,复合鱼糜凝胶强度最大。根据此配方（优化工艺组）所得复合鱼糜质构特性参数中的咀嚼性、粘结性、破断力与破断距离均显著高于未添加外源物普通工艺组（P<0.05）,同时优化工艺组的复合鱼糜的扫描电镜图显示其凝胶结构网状结构较为致密,凝胶孔洞较小,证明了外源添加物有助于改善复合鱼糜凝胶强度。     

不同天然抗氧化剂乳液对冷藏鱼丸贮藏品质变化的影响分析

为探究天然抗氧化剂乳液的添加对冷藏鱼丸保鲜效果的影响，该研究以酪蛋白为乳化剂构筑水包油乳液体系，探究酪蛋白添加量及贮藏时间对乳液稳定性的影响。将添加不同天然抗氧化剂（鼠尾草酸、苹果多酚、葡萄籽多酚）乳液与鱼糜混合制成鱼丸，以鱼丸的硬度、弹性、凝胶强度、硫代巴比妥酸值（TBA）、菌落总数以及感官评分为考察指标，探究不同抗氧化剂乳液对鱼丸在4 ℃贮藏期间品质的影响。研究发现，酪蛋白质量分数为2%时的乳液贮藏14 d后粒径为372.33 nm，电位为33.53 mV，稳定性最好。天然抗氧化剂乳液可显著改善贮藏过程中鱼丸的硬度、凝胶强度、硫代巴比妥酸值及菌落总数（P<0.05）。此外，经鼠尾草酸-酪蛋白乳液处理的鱼丸在贮藏末期的硬度为511.79 g，凝胶强度为293.64 g，硫代巴比妥酸值为0.64 mg/kg，显著优于苹果多酚-和葡萄籽多酚-酪蛋白乳液组，且在贮藏第12天后的菌落总数为4.95 lg CFU/g，仍在标准范围内。该研究成果表明鼠尾草酸-酪蛋白乳液对鱼丸贮藏期间的品质保持效果最好。     

表没食子儿茶素没食子酸酯对冷冻罗非鱼鱼糜抗冻作用机制

通过肌原纤维蛋白理化指标、鱼糜凝胶特性的测定及十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（sodium dodecyl sulfate-polyacrylamide gel electrophoresis,SDS-PAGE）,研究表没食子儿茶素没食子酸酯（epigallocatechin gallate,EGCG）对冷冻罗非鱼鱼糜的抗冻效果并探讨其作用机制。结果表明,罗非鱼鱼糜中添加EGCG具有一定的抗冻效果,对比空白组具有显著差异性。冻藏期间空白组鱼糜中盐溶性蛋白含量、总巯基含量分别下降了68.2%和62.9%,而添加0.01% EGCG后二者的降幅分别为54.5%和49.2%,且EGCG还明显延缓了肌原纤维蛋白的氧化羰基化作用。此外,冻藏过程中,EGCG组和空白组鱼糜凝胶强度和持水性随冻藏时间延长逐渐降低,且EGCG添加量较大时,反而加快凝胶劣化。SDS-PAGE显示,EGCG能够有效抑制肌原纤维蛋白降解,其中质量分数为0.01%的EGCG效果最佳。EGCG能延缓肌原纤维蛋白变性和降解程度,延缓鱼糜氧化变质程度,有望成为一种新型的鱼糜抗冻剂。     

外源添加物对海杂鱼鱼糜凝胶特性的影响

为改善海杂鱼鱼糜的凝胶特性,通过单因素试验探究谷氨酰胺转氨酶（transglutaminase,TGase）、蛋清蛋白粉、复合磷酸盐添加量对海杂鱼鱼糜凝胶强度和持水性的影响,并采用响应面法对重组配方进行优化,确定外源添加物最佳添加量。最后采用质构仪、流变仪、核磁共振仪以及扫描电镜对优化组的鱼糜凝胶性能进行验证。结果表明,TGase添加量为0.4%,蛋清蛋白粉添加量为7.0%,复合磷酸盐添加量为0.30%时,鱼糜凝胶强度最大。与不含添加物的对照组相比,最佳添加量条件下鱼糜的质构特性、流变学特性、水分分布以及微观结构均显著提升（P<0.05）。本研究为海杂鱼鱼糜品质特性的改良提供参考依据和技术指导。     

添加微细鲽鱼鱼骨泥对金线鱼鱼糜凝胶品质的影响

以鲽鱼骨为研究对象,首先采用湿法超微粉碎技术将其加工成微细骨泥,再将其添加到金线鱼鱼糜制品中开发高钙鱼糜制品,从鱼糜溶胶pH值、肌原纤维蛋白Ca2＋-ATP酶活力、凝胶强度、质构、持水性、色泽、凝胶溶解度、微观结构方面探讨添加不同质量分数（2.5%～12.5%）鱼骨泥对鱼糜制品凝胶品质的影响。结果显示：添加微细鱼骨泥不影响鱼糜正常凝胶的pH值;较低质量分数（不超过5.0%）时,鱼骨泥中的Ca2＋可以激活鱼糜溶胶中肌原纤维蛋白的ATP酶,显著提升Ca2＋-ATP酶活力;鱼糜凝胶的凝胶强度、质构、持水性、色泽指标均在添加质量分数5.0%鱼骨泥时达到最高值,而凝胶溶解度达到最低值。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析和扫描电子显微镜观察结果表明,添加质量分数2.5%～5.0%鱼骨泥一定程度上促进了肌球蛋白重链（myosin heavy chain,MHC）的交联,可以促进鱼糜凝胶形成致密均匀的网状结构,过量添加则会影响MHC交联和凝胶网络致密性。     

干热处理蛋清粉改善鲢鱼鱼糜凝胶性的研究

为提高鲢鱼鱼糜制品的凝胶性,将蛋清粉与干热处理蛋清粉添加至鲢鱼鱼糜中。利用质构仪、色差计分析蛋清粉与干热处理蛋清粉对鲢鱼鱼糜凝胶性与色泽的影响。试验结果表明,未添加蛋清粉的鱼糜凝胶强度、白度为585.62 g·cm和75.56,添加1.5%的蛋清粉或2.5%的干热处理蛋清粉可显著提高鲢鱼鱼糜的凝胶性与白度,且干热处理蛋清粉的改善效果要优于普通蛋清粉。扫描电镜结果表明,普通鲢鱼鱼糜所称凝胶空隙较大,质地松软,而添加蛋清粉后凝胶质地变紧密,尤其是添加干热处理蛋清粉后,其凝胶间隙明显变小,凝胶切面变平滑。     

丙酸杆菌发酵提取物-乳酸链球菌素复配对熏煮香肠品质的影响

为延长熏煮香肠的货架期、保持其食用品质,该文研究了丙酸杆菌发酵提取物（Propionibacterium fermented extract,PFE）和乳酸链球菌素（Nisin）复配对熏煮香肠贮藏期间品质、氧化程度及微生物的影响。分别将0.01%、0.02%、0.03%的Nisin与0.30%的PFE复配后添加到熏煮香肠中,探究其在贮藏期间（4 ℃）颜色、质构、硫代巴比妥酸值（Thiobarbituric acid reactive substances,TBARS）和菌落总数的变化,并与0.30% PFE和0.03% Nisin作比较,同时通过高通量测序分析贮藏过程中熏煮香肠的微生物多样性。结果显示,PFE与Nisin复配后显著提高香肠的L*值和a*值并降低b*值（p<0.05）,显著降低产品的硬度、咀嚼性和弹性（p<0.05）。0.3%PFE复配0.01%和0.02% Nisin的处理组抑制脂肪氧化的效果显著优于单独添加Nisin和PFE的处理组（p<0.05）。复配处理组的菌落总数在整个贮藏期间均显著小于其它处理组（p<0.05）,且复配0.01% Nisin的处理组在贮藏后期表现出更好的抑菌效果。通过高通量测序技术发现Nisin与PFE复配添加对葡萄球菌属、不动杆菌属和芽孢八叠球菌属均表现出更好的抑制效果。PFE复配Nisin后可有效抑制熏煮香肠的脂肪氧化和微生物生长,更好地保持熏煮香肠在贮藏期间的品质,其中0.01%的Nisin复配比例的综合表现最佳。     

13种植物多酚提取物抗氧化活性分析及其对冻藏未漂洗鱼糜品质的影响研究

提高未漂洗鱼糜比漂洗鱼糜得率高,环境友好,但品质较差,主要表现在脂质氧化明显,凝胶强度低。本文比较分析了石榴、芝麻、蓝莓、姜黄、迷迭香、薄荷、葡萄、橄榄、草莓、马鞭草、茶籽、燕麦、莲子皮等13种植物的多酚提取物的抗氧化活性及对冻藏未漂洗鱼糜脂质氧化、凝胶强度的影响。迷迭香多酚提取物对羟自由基清除率最高,达到87.56%±0.28%;石榴多酚提取物对超氧阴离子的清除率最高,为79.35%±0.13%;葡萄多酚对脂氧酶抑制率最高,为89.04%±2.01%。新鲜鱼糜丙二醛含量为(0.18±0.01) mg/kg,冻藏3d后,急剧增加至0.54±0.04mg/kg,添加葡萄多酚的鱼糜最低,为(0.23±0.02) mg/kg。添加姜黄多酚的冻藏未漂洗鱼糜凝胶强度最高,为1049.85 g.mm,空白为527.15 g.mm。葡萄多酚和姜黄多酚比例为1:1时,未漂洗鱼糜TBARS最低,为(0.37±0.02) mg/kg;凝胶强度最高,为(1249.97±13.31) g*mm。本文为未漂洗鱼糜贮藏加工提供了理论支撑和参考。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

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.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.     

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.