市售条件下冷鲜鲟鱼肉货架期及品质变化规律研究

模拟冷鲜鲟鱼的市售环境(托盘覆膜包装置于4℃、4℃+吸水垫片和0℃贮藏),通过感官指标、微生物指标、理化指标以及肌肉质构分析和微观观察,研究冷鲜鲟鱼肉在不同市售环境下的货架期及品质变化规律。结果表明:冷鲜鲟鱼在4℃、4℃+吸水垫片和0℃条件下贮藏的货架期分别为5、4 d和7 d;贮藏至第8天时,3种贮藏环境下鲟鱼肉的菌落总数、TVB-N值和TBA值均超过国标规定的鲜度指标;贮藏至第8天时,贮藏在0℃下的鲟鱼肉的硬度、弹性、回复性分别达到贮藏在4℃下鲟鱼肉的1.14、1.29、1.15倍,是贮藏在4℃+吸水垫片的1.39、1.07、1.18倍;对比贮藏初期和后期鲟鱼肉的肌肉组织结构的电镜图可以明显看出0℃下的鲟鱼肉肌原纤维排列紧密,黏结少,排布较规整。结论:不同贮藏温度对冷鲜鲟鱼肉货架期及品质影响显著,温度越低越利于鱼肉良好品质的维持;市售中常用的4℃+吸水垫片的包装方式对鲟鱼肉货架期的延长并没有显著的影响。     

二氧化氯对鲳鱼微冻贮藏品质的影响

用二氧化氯（ClO2）处理鲳鱼块后进行微冻（－3 ℃）贮藏,测定贮藏期间鱼肉的菌落总数、菌相、总挥 发性盐基氮（total volatile basis nitrogen,TVB-N）含量、K值、pH值及肌原纤维储能模量（G’）的变化,考察ClO2 处理对鲳鱼块微冻贮藏品质的影响。结果表明：30 μg/mL ClO2处理（料液比1∶20（m/V）,浸泡10 min）可以使鱼 块的初始菌落总数降低约2 （lg（CFU/g））。贮藏过程中,处理组鱼块的菌落总数始终低于对照组,但贮藏初期 处理组鱼块的细菌生长速率明显高于对照组;2 组鱼块的优势腐败菌均由初期的希瓦氏菌属过渡到末期的假单胞菌 属;根据鱼肉的TVB-N含量,对照组于贮藏第20天变为二级鲜度,而处理组在贮藏的32 d内一直处于一级鲜度; ClO2处理使鱼肉初始pH值下降0.52,贮藏期间处理组鱼肉的pH值始终低于对照组约0.2～0.4;贮藏期间2 组鱼肉 的K值差别不大,对照组和处理组分别于贮藏12、16 d达到40%;处理组鱼肉的肌原纤维蛋白G’峰值始终高于对照 组。上述结果表明,ClO2处理结合微冻贮藏能够有效提升鲳鱼块鲜度、延长其货架期。     

酸性电解水前处理对鲟鱼肉冰温贮藏品质的影响

目的考察酸性电解水(acidicelectrolyticwater,AEW)前处理对鲟鱼肉冰温贮藏品质的影响。方法利用有效氯浓度(available chlorine concentration, ACC)不同的AEW处理鲟鱼块后进行冰温(–1℃)贮藏,测定贮藏期间鱼肉的菌落总数、挥发性盐基氮(total volatile basic nitrogen, TVB-N)含量、K值、pH值及硫代巴比妥酸值(thiobarbituric acid reactive substances, TBARS)的变化。结果经AAC分别为67、49、36 mg/L的AEW处理后,鲟鱼块减菌率分别高达99.7%、98.9%和96.5%,且贮藏期间菌落总数始终保持ACC67组ACC49组ACC36组对照组。与对照组相比,AEW处理能有效延缓鲟鱼肉pH值、TBARS值、TVB-N值、K值的上升, ACC含量越高,延缓作用越强。结论 AEW前处理能够有效提升冰温贮藏鲟鱼肉的鲜度、延长其贮藏期,ACC67、ACC49、ACC36组分别可将鲟鱼肉冰温贮藏期延长8～11 d、6～8 d、2～4 d。     

减菌处理对金鲳鱼块微冻贮藏品质的影响

目的考察酸处理对金鲳鱼块微冻贮藏品质的影响。方法用0.05%(m:V)食品级HCl处理鲳鱼肉块(1:20料液比,浸泡10 min,然后用预冷无菌水冲洗)后进行微冻贮藏(-3℃),测定TVB-N、K值、pH、菌落总数(total plate count,TPC)、菌相及肌原纤维弹性模量的变化。结果酸处理可降低鱼块菌落总数2.28log CFU/g。对照和处理组分别于24、30 d后超过6 log CFU/g,于30、36 d后出现异味。处理组菌落总数始终低于对照组,但贮藏初期处理组细菌生长速度明显高于对照组。两组的优势腐败菌均由贮藏初期的希瓦氏菌过渡到中期的希瓦氏菌、环丝菌及假单胞菌,直到末期的假单胞菌。根据TVB-N含量,对照和处理组分别于20、24 d后鲜度降至二级。酸处理使鱼肉初始pH值(6.7)下降0.4,贮藏4 d后两组p H值降至最低,之后开始升高,12 d后两组pH值几乎相同,24 d后均回升至初始pH水平。贮藏期间两组K值差别不大,均于贮藏16 d后达到40%成为二级鲜度。两组肌原纤维蛋白的储能模量峰值随着贮藏时间延长而下降,酸处理组于贮藏18 d后下降速度变缓,贮藏24 d后,酸处理组开始明显高于对照组。结论 0.05%HCl处理能够在一定程度上延长微冻贮藏鲳鱼块的鲜度和货架期。     

抑菌流化冰提高白鲳鱼的贮藏品质

为了提高冰鲜海鱼的品质,对比研究了3种抑菌物质二氧化氯(Cl O2)、乳酸链球菌素(Nisin)和二甲基二碳酸盐(DMDC)制备的流化冰在24天贮藏期内对白鲳鱼品质特性的影响。结果显示:在平均温度为1℃的贮藏环境中,随着冰鲜时间的延长,白鲳鱼的TVB-N值和TBARS值升高,升高幅度显著小于普通流化冰(p<0.05),TVB-N值显示Cl O2样品24 d为33.47 mg/mL,DMDC样品20 d为34.45 mg/mL,Nisin样品16 d为37.41 mg/mL,普通流化冰样品12 d为39.53 mg/mL,抑菌流化冰延长了白鲳鱼的货架期。抑菌流化冰可以促进白鲳鱼鱼肉p H值、硬度、弹性和色度等的稳定性,证明Cl O2抑菌流化冰样品的新鲜度保持更好。通过研究白鲳鱼在不同贮藏环境中的品质变化,建立微生物学Logistic模型能够较准确地预测白鲳鱼在冰鲜保藏温度-1至5℃的货架期,其相对误差范围不超过3.22%。研究结果有助于提高白鲳鱼等海洋鱼在贮藏期间的品质,延长其货架期。     

不同温度下鲳鱼品质及微观组织的变化研究

为探究鲳鱼在不同温度贮藏下货架期情况,本文对冷藏(4℃)、微冻(-3℃)和冻藏(-18℃)条件下鲳鱼的菌落总数(APC)、pH值、挥发性盐基氮(TVB-N值)、K值、肌动球蛋白含量、总巯基含量和微观组织等指标进行研究。结果表明:随着贮藏时间延长三种贮藏方式鲳鱼菌落总数、pH、TVB-N值和K值上升,至三种贮藏方式实验终点,鲳鱼TVB-N分别在第6 d,20 d和60 d时达到0.35 mgN/g、0.40 mgN/g,0.16 mgN/g,说明冻藏能有效的延缓鲳鱼腐败变质;三种贮藏方式鲳鱼肌动球蛋白溶出量与巯基含量呈现下降趋势。肌纤维间冰晶形成程度随贮藏温度不同呈现不同趋势,贮藏至第20 d,因为冰晶的形成冷冻组鲳鱼肌纤维组织结构破坏程度大,肌纤维发生大规模位移和形变,微冻组鲳鱼肌纤维仅发生部分位移,说明微冻贮藏方式能更好保持鲳鱼良好的肌纤维组织形态。     

不同温度贮藏对黄鳍鲷鱼肉鲜度与品质的影响

以黄鳍鲷（Acanthopagrus latus）为研究材料,通过测定鱼肉菌落总数、pH值、挥发性盐基氮（total volatile basic nitrogen,TVB-N）值、硫代巴比妥酸（2-thiobarbituric acid,TBA）值和剪切力等指标,结合感官评定,设立4℃冷藏为对照组,研究0℃和微冻（-4℃）贮藏对黄鳍鲷鱼肉鲜度和品质的影响。结果表明：在贮藏期间,各贮藏组黄鳍鲷鱼肉的菌落总数、TVB-N和TBA值均呈现上升趋势,鱼肉pH值呈先稍下降后再上升的趋势,而鱼肉剪切力和感官评分均呈逐渐下降趋势。0℃和微冻两贮藏组黄鳍鲷鱼肉各项指标的变化速率均小于4℃冷藏对照组,0℃和微冻保鲜效果明显优于4℃冷藏保鲜;0℃和微冻贮藏组,黄鳍鲷贮藏7 d后鱼肉菌落总数分别为6.88 lg（CFU/g）和5.72 lg（CFU/g）,TVB-N值分别为20.54 mg/100 g和11.40 mg/100 g,TBA值分别为0.88 mg/100 g和0.38 mg/100 g,剪切力分别为4.96 N和5.51 N,说明微冻贮藏能更好地抑制鱼肉微生物繁殖,有效地减缓鱼肉蛋白质分解和脂肪氧化,较好地保持鱼肉嫩度和品质;相比于4℃冷藏,0℃和微冻下贮藏的黄鳍鲷鱼肉货架期至少可延长2 d和8 d。     

鲫鱼在冷藏和微冻贮藏下品质变化的研究

以感官品质、pH、硫代巴比妥酸(TBA)、总挥发性盐基氮(TVB-N)和鲜度指标K值、细菌总数为指标,研究鲫鱼在冷藏(4℃)和微冻(-3℃)贮藏中品质的变化规律.结果表明,鲫鱼在4℃和-3℃贮藏条件下,分别在第8d和第24d达到感官品质接受上限.4℃条件下第14d TBA值为1.29mg/100g,-3℃贮藏条件下第30d TBA值为1.58mg/100g.4℃条件下贮藏8d TVB-N值为18.76mg/100g,-3℃贮藏24d TVB-N值为18.52mg/100g.4℃贮藏8d和-3℃贮藏24d的鲫鱼K值分别为56.7％和53.2％.4℃贮藏12d细菌总数为7.02lg cfu/g,3℃贮藏30d为5.78lg cfu/g.综合各指标变化,4℃和-3℃条件下鲫鱼的货架期分别为8d和24d,与冷藏相比,微冻能明显的延长鲫鱼的货架期.     

秋刀鱼-20℃、-30℃和-50℃冻藏过程中品质变化

为了探究秋刀鱼冻藏过程品质变化,以蒸煮损失率、TVB-N值、肌原纤维蛋白含量、巯基含量、TBARS值为指标,并结合肌肉组织结构观察,对-20、-30℃和-50℃3个温度条件下秋刀鱼的品质变化进行了研究。结果表明,冻藏温度对秋刀鱼品质有较大影响。总体上,温度越低,秋刀鱼品质劣化程度越低,各项理化指标的值也更接近新鲜鱼肉的水平。秋刀鱼肌肉蒸煮损失率、TVB-N值和TBARS值随冻藏时间的延长不断上升,冻藏180 d时-20℃组TVBN值极显著高于另两组(P0.01),而-30℃和-50℃组间差异较小;冷冻贮藏导致肌肉蛋白变性,肌原纤维蛋白含量与活性巯基含量逐渐降低,其中-20℃组下降速率较快;冻藏结束时,3组秋刀鱼TBARS值差异显著(P0.05),-20℃组TBARS值为1.10 mg/kg已达到脂肪轻微酸败程度;肌肉显微结构表明,冻藏温度越高,会造成肌纤维之间更大的空隙且破坏更多的肌肉纤维束。从品质保持效果和经济效能角度,-30℃适宜作为秋刀鱼的冻藏温度。     

不同贮藏温度下鲫鱼鱼片品质变化研究

为探究不同贮藏温度下鲫鱼鱼片保鲜效果,试验设置0℃(冰藏)、4℃(冷藏)、-3℃(微冻)和-18℃(冻藏)4组试验,以质构分析、硫代巴比妥酸(TBA)、高铁肌红蛋白、挥发性盐基氮(TVB-N)、微生物等指标变化为依据测定不同贮藏温度条件下鲫鱼鱼片的品质变化。结果表明,随着贮藏时间的延长,不同贮藏温度条件下鲫鱼鱼片的质构特性、高铁肌红蛋白、挥发性盐基氮(TVB-N)、菌落总数均出现不同程度的上升,温度越高,上升速度越快。其中,4℃(冷藏)下的鲫鱼鱼肉的贮藏货架期为9 d,0℃(冰藏)下的鲫鱼鱼肉的货架期为15 d,-3℃(微冻)和-18℃(冻藏)下鲫鱼鱼肉的货架期较长。综合各项理化指标可知鲫鱼鱼片在微冻和冰温、冻藏条件下保鲜效果明显优于冷藏。     

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.     

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.     

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     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press     

INFOPRINT 2014 was Successfully Held in Dongguan

Sponsored by Printing and Printing Equipment Industries Association of China （PEIAC） and organized by Print China magazine, the Seventeenth Beijing International Printing Information Conference （INFOPRINT 2014） was successfully held on 11th Dec. 2014 at Dongguan Exhibition International Hotel.