苹果新型高效蓄冷剂特性及应用效果研究

针对冰蓄冷剂在果蔬保鲜及短途冷链运输过程中相变潜热低、蓄冷效果不显著等问题,以及苹果常温贮运易腐烂、营养损失等产业难题。以JH-Y-A、JH-Y-B新型蓄冷剂为试材,采取空箱试验设计、温度差计算冷量方法,对其蓄冷特性进行研究,并将2种相变蓄冷剂分别应用于苹果蓄冷保鲜试验中,以冰蓄冷剂作为空白对照。通过模拟运输环境温度(25 ℃),测定56 h内果实回温曲线及理化指标,以阐述新型蓄冷剂保鲜效果。结果表明,JH-Y-B蓄冷剂释放冷是冰蓄冷剂的1.2倍,至模拟蓄冷保鲜结束,试验组果实回温均低于对照组(17.3 ℃),均能有效维持可溶性固形物含量,保持苹果硬度及失水状况,苹果品质均优于对照组。研究表明该新型相变蓄冷剂蓄冷贮藏能力好,能减缓果蔬品质损失,为果蔬简约蓄冷保温技术应用奠定理论基础。     

复合相变蓄冷材料的制备及对香菇贮藏品质的影响

为了研发相变温度适宜、相变潜热高、热性能参数稳定的低温复合相变蓄冷材料,研究了氯化钾、甘氨酸、高吸水树脂(superabsorbent ploymer,SAP)3种材料复合的相变蓄冷材料,在单因素试验基础上,利用Box-Behnken试验设计原理,以相变潜热为响应值,优化出最佳成分质量分数(氯化钾2%、甘氨酸1.37%、SAP 3.37%),并对其性能进行了冻融循环测试以及探究了对香菇贮藏品质的影响。结果表明:香菇贮藏实验中保温箱内的温度差异说明了研发型复合相变蓄冷材料较市售材料有更高的潜热,且冻融循环20次后的研发型复合相变蓄冷材料无相分离现象,温湿度记录仪对冻融前后冻结曲线的记录结果表明研发型复合相变蓄冷材料具有较好的热稳定性;而且在室温25℃条件下,研发型复合相变蓄冷材料较市售蓄冷材料可以更好地保持香菇色泽和较低的质量损失率,抑制膜脂过氧化代谢,延缓香菇衰老。     

环保型蓄冷剂的制备及包装应用

目的:制备一种环保型蓄冷剂,并以现摘草莓为包装对象加以包装应用。方法:以甘露醇溶液与碳酸钠(Na2CO3)溶液为主储能剂,硼砂和羧甲基纤维素钠(CMC)分别为成核剂和增稠剂,加入游离水来提高体系的相变潜热;将制备的蓄冷剂用薄膜封口后冷冻至凝固,然后将其置于温控包装箱的6个表面后装入适量草莓,置于25℃的恒温环境中,记录试样在不同时间的温度变化,验证所制备蓄冷剂的蓄冷效果。结果:最佳制备配方为:6%甘露醇,2%Na2CO3,2%硼砂,5%CMC。该蓄冷剂相变温度在5℃左右,过冷度较小,无相分离现象,相变潜热为290.2 k J/kg。结论:所制备蓄冷剂具有良好的实用价值。     

食品相变蓄冷剂的配方优化及应用

对KCl溶液、NaCl溶液作为食品相变蓄冷剂的配方进行优化,通过添加人工晶核改善蓄冷剂的过冷性能,并筛选合适的蓄冷载体.结果显示:1％ SiO2和0.1％ CuS能够较好地减少KCl溶液的过冷现象,3％四硼酸钠(Na2B4O7)能较好地改善NaCl溶液的过冷现象,它们都可以用作相变蓄冷剂的人工晶核.SAP(超吸水性树脂...     

蓄冷材料结合保鲜剂对南美白对虾的保鲜效果研究

研究高分子吸水树脂结合3种具有保鲜防腐功能的蓄冷剂,在不同浓度下对南美白对虾的保鲜效果。试验结果表明,试验进行到1 h时,装有4 kg高分子吸水树脂的泡沫箱内的温度达到2℃以下,而且保持7℃以下的时间超过30 h;相比冰块,高分子吸水树脂蓄冷剂更能延长泡沫箱内对虾的保冷时间,提高保鲜效果。其中,以13%Na2SO3-高分子吸水树脂的蓄冷剂保鲜效果最佳,可延长南美白对虾保藏时间至30 h。     

反相悬浮聚合法制备相变蓄冷材料及其应用

为提升吸水树脂（superabsorbent resin, SAR）的吸水能力,增加其用作蓄冷材料的潜热,采用了单因素实验结合Box-Behnken试验的方法,将反相悬浮聚合法制备SAR的条件进行了优化,并通过双孢菇的贮藏实验表明了其蓄冷效果。结果表明:制备SAR的最优反应条件为:交联剂为单体丙烯酸（AA）质量的0.06%,引发剂0.9%,分散剂4.38%,淀粉10%,中和度75%,反应单体AMPS:AA为1:10,反应温度65 ℃,产物单位吸水量为573.26 g/g;吸水量的增加提升了制备蓄冷材料在保温箱中保持环境低温的能力,可以在12 h内基本保持10 ℃以下的低温环境,而且在25 ℃条件下,可以更好地保持双孢菇色泽,抑制失重、刺激气味的产生和质构的变化,表明通过优化SAR吸水性对其蓄冷性能的提升可以更好地保持双孢菇贮藏品质。     

包装方式对西兰花物流保鲜品质的影响

为减少蓄冷剂用量,研究普通聚乙烯(polyethylene,PE)包装袋与微孔PE包装袋协同蓄冷剂的复合保鲜技术对西兰花物流保鲜品质的影响。结果表明:放入4袋蓄冷剂组比不放蓄冷剂组保鲜效果要好,而放入2袋蓄冷剂结合PE包装袋优于4袋蓄冷剂组,2袋蓄冷剂结合PE微孔袋包装的效果最佳。说明PE包装袋特别是PE微孔袋的协同使用可以弥补蓄冷剂用量减少后温度升高带来的保鲜品质下降问题,为解决目前蓄冷剂用量过大导致的成本升高难题提供了新的思路。     

紫红长茄蓄冷贮藏品质实验研究

环境温度30℃,采用相变温度为5.8℃的高温相变蓄冷剂,使用蓄冷保温箱对紫红长茄蓄冷贮藏品质进行实验研究,测试蓄冷保温箱内温度和茄子中心温度变化,每隔24 h对紫红长茄进行取样,通过多人打分方式对其感官评定,测试其硬度、可溶性固形物和Vc含量。结果表明:实验进行66 h蓄冷剂完全液化,比预计时间少6 h,按公式[m=k A(t_s-t_0)τ/r_0]计算的蓄冷剂质量偏小;PE塑料保鲜膜包装茄子在感官评价、硬度、可溶性固形物含量和Vc含量方面均高于无膜包装茄子;PE塑料保鲜膜包装茄子感官评价降低1.4分,硬度降低1.67 N,可溶性固形物含量下降了0.4%,Vc含量降低了0.4 mg/100 g,茄子感官和营养品质变化不大。     

用于冷链运输的复合相变蓄冷剂主储能剂研制

研制了一种用于冷链运输的三元复合相变蓄冷剂的主储能剂。以有机物甘露醇(C6H14O6)水溶液作为主储能剂,无机物氯化钾(KCl)水溶液为相变温度调节剂,经充分混匀,用差示扫描量热仪研究主储能剂的热物性,并测试其T-t曲线来判断其稳定性。结果表明,当C6H14O6/KCl溶液的浓度比(mol/L)为0.6∶0.2,且水溶液体积按1∶1混合时,该复合物可以达到相变潜热在290 J/g以上,Onset温度在-6~-4℃的主储能剂要求。测得Onset温度为-5.1℃,相变潜热为296.3 J/g,且无分层,无过冷,无相分离现象。主储能剂的原料无毒无害,价格便宜易得。其化学性能稳定,能长期反复使用,可以大规模应用于低温物流、冷链运输等领域。     

精准温度控制对蓝莓的低温保鲜效果

为研究精准温度控制技术在蓝莓保鲜中的应用效果,该研究采用了对照组和3个精准温控组,分别是将蓝莓装入泡沫箱（control check,CK）、泡沫箱+蓄冷剂（冰温1）、精准温控箱（冰温2）和精准温控箱+蓄冷剂（相温）中,记录箱内温度,结合贮藏期间蓝莓的品质变化,通过主成分分析法对四组蓝莓进行综合评价,以得到最佳精准温度控制的处理方式。结果表明,冰温贮藏的箱内温度更低,相温贮藏箱内温度较CK波动更小,贮藏第60 d时,相温组蓝莓的好果率、软果率、风味指数及果霜覆盖指数分别为79.54%、17.87%、72.22%、76.00%,色泽变化低于2,L值达27.03,此外,精准温度控制贮藏的蓝莓硬度更高,可溶性固形物、可滴定酸、Vc、花青素等营养物质消耗速度更慢,其中CK组蓝莓贮藏期间Vc含量分别比精准温控组多下降了5.01、9.18、16.67 mg/100 g,经主成分分析后得到四组蓝莓的品质排序为相温组>冰温2组>冰温1组>CK组,且精准温度控制贮藏的蓝莓醛类、萜类、酯类等有利香气成分相对含量更高。因此,精准温度控制技术有利于蓝莓的冷藏保鲜,其中相温贮藏效果更好。     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the