可食天然复合保鲜膜对低温肉制品的保质研究

利用可食性胶原蛋白和壳聚糖与乳酸链球菌素(Nisin)等制成的天然复合保鲜膜对低温肉制品进行浸渍、杀菌、真空包装等处理后,分别置于微温(30~40℃)、常温(20~25℃)、冷藏(0~4℃)3种不同温度条件下贮藏,测定不同贮藏期菌落总数、TVB-N、H2S等指标及感官评定。结果表明,Ⅰ组(2%胶原蛋白 0.05%Nisin 0.03%VE 0.25%茶多酚)和Ⅱ组(2%胶原蛋白 2%壳聚糖 1%醋酸 0.05%Vc 0.03%烟酰胺)的复合保鲜膜处理,其保质期均优于对照组。在微温条件下,Ⅰ、Ⅱ组的保质期分别达30、40d,比对照分别延长10、20d;常温下Ⅰ、Ⅱ组的保质期分别达120、150d,分别比对照延长60、90d;经冷藏的Ⅰ、Ⅱ组保质期均为240d,比对照组延长90d。综合评价以Ⅱ组略好。     

不同冰温贮藏条件对鸡肉贮藏期的影响

试验对比研究了-0.5±0.5℃贮藏、使用复合保鲜剂-0.5±0.5℃贮藏、使用复合保鲜剂-2.0±0.5℃贮藏,三种不同冰温贮藏条件下,鸡胸肉TVB-N值、TBA值、TVC对数值的变化。试验表明:在-0.5±0.5℃冰温贮藏时使用复合保鲜剂处理鸡胸肉,比不使用保鲜剂处理鸡胸肉保鲜期延长了约4d;使用复合保鲜剂处理后鸡胸肉在-2.0±0.5℃环境中,冰温贮藏比-0.5±0.5℃冰温贮藏时保鲜期延长了约15d。使用复合保鲜剂以及较低的冰温贮藏温度,均能提高鸡肉在冰温贮藏条件下的保质期。     

蒸煮贻贝冰温贮藏保鲜剂的筛选、优化及评价

目的：筛选用于改善冰温贮藏贻贝品质、延长贻贝保质期的生物保鲜剂,对复合保鲜剂的配方及保鲜工艺进行优化,并评价其保鲜效果。方法：通过测定保鲜剂作用于贻贝优势腐败菌的抑菌圈大小,筛选出抑菌效果较强的保鲜剂,运用响应面法优化复合保鲜剂配方,采用肉汤稀释法测定最小抑菌浓度(minimum inhibitory concentration,MIC);利用正交试验确定复合保鲜剂用于蒸煮贻贝保鲜的最佳工艺;通过测定蒸煮贻贝冰温贮藏8天后的感官评分、pH值、挥发性盐基氮(total volatile basic nitrogen,TVB-N)含量、菌落总数、汁液流失率来评价复合保鲜剂的效果。结果：筛选出的三种保鲜剂分别为溶酶菌、乳酸链球菌素和丁香酚,复合保鲜剂对枯草芽孢杆菌和假单胞菌的MIC分别为16 μg/mL、8 μg/mL,复合保鲜剂的优化配方(质量分数)为溶菌酶4%、乳酸链球菌素2%和丁香酚0.75%,最佳保鲜工艺为保鲜剂溶液pH 5.5、料液比1:2.5（m:V）,浸泡时间60 min,采用优化的配方和工艺用于蒸煮贻贝的冰温贮藏,贻贝品质的综合评分为空白样品的2倍。结论：复合保鲜剂可以有效改善蒸煮贻贝在冰温贮藏条件下的鲜度和品质,延长保质期,从而拓宽物流范围。     

烧鸡的防腐与保鲜

实验以烧鸡鸡肉为原材料,对烧鸡的防腐保鲜进行初步研究。根据培养条件培养鸡肉细菌来做抑菌试验,通过对不同防腐保鲜液的抑菌实验,筛选出最佳保鲜液;再结合真空包装和微波杀菌的保鲜方法,进行贮藏。结果表明:最佳复合保鲜剂配方为Nisin浓度0.05,溶菌酶浓度0.05,双乙酸钠浓度1的保鲜液。将烧鸡鸡肉浸泡于此保鲜液中60s,再进行真空包装和微波杀菌,在36℃条件下,至少可保藏11d,其微生物、感官指标均在国标允许范围内,可以有效延长鸡肉的保质期。     

复合生物保鲜剂对冷藏红鳍东方鲀的保鲜效果研究

为了验证复合生物保鲜剂对冷藏红鳍东方鲀的保鲜效果,本实验选择水浓度为0.68%的柠檬酸、1.45%的百里酚以及1.94%的海藻酸钠的复合生物保鲜剂处理红鳍东方鲀,将其贮藏在冷藏(4±1)℃条件下,并设置未经保鲜剂处理的鱼肉为对照组,以pH、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBA)、菌落总数、假单胞菌数及汁液流失率为指标,评价复合生物保鲜剂的保鲜效果。结果表明:保鲜组可以显著减缓pH和TVB-N值的上升,延缓鱼肉的氧化,抑制菌落总数和假单胞菌属的生长繁殖,贮藏12 d时接近食用上限。对照组在贮藏6d时已腐败变质,货架期大约在5d左右;保鲜组在贮藏12d时汁液流失率为1.63%,与对照组贮藏6d时无差异(p0.05)(1.63%),显著低于气调保鲜法的汁液流失率。结论:综合各指标的测定,复合生物保鲜剂对冷藏红鳍东方鲀保鲜效果显著,可以将货架期由5d延长至12d左右。     

响应面法优化冷鲜鸡复合生物保鲜剂配比

为了延长冷鲜鸡的货架期,在单因素实验的基础上,利用Box-Behnken实验设计和响应面法研究了由牛至精油、茶多酚和D-异抗坏血酸钠配制的复合保鲜剂对冷鲜鸡胸肉的保鲜效果。建立了以挥发性盐基氮(TVB-N)含量为响应值的二次回归模型,确定了复合生物保鲜剂中各种组分的最佳配比。将优化的复合生物保鲜剂应用于鸡肉保鲜,通过测定感官评定、质构、色差、p H、菌落总数、TVB-N以及硫代巴比妥酸(TBA)值等指标,对其保鲜效果进行了验证。结果表明:三种生物保鲜剂的最佳添加量为牛至精油0.786%、茶多酚0.164%和D-异抗坏血酸钠0.031%,此时TVB-N可达81.89 mg/100 g。经复合保鲜剂处理过的冷鲜鸡胸肉在4℃下贮藏时,可将货架期由常规冷藏对照组的7 d延长至11~12 d。     

香辛料保鲜液与壳聚糖魔芋葡甘聚糖复合膜在冰鲜鸡肉保鲜中的应用

为延长冰鲜鸡肉的保鲜期,采用肉桂精油、生姜精油为保鲜剂,壳聚糖和魔芋葡甘聚糖(konjac glucomannan,KGM)作为涂膜材料,以冰鲜鸡肉挥发性盐基总氮(total volatile basic nitrogen,TVB-N)、pH值、汁液流失率和菌落总数为指标,基于单因素试验和四因素三水平的正交试验,考察肉桂、生姜精油作为天然保鲜剂添加到可食性膜溶液中对冰鲜鸡肉的保鲜作用,以达到减少冰鲜鸡肉保存和运输过程中水分过度散失、延长保质期、减少化学合成防腐剂的使用以及资源浪费的目的,为冷链运输及延长冷鲜肉在超市中的货架期提供参考。试验结果表明,0.9%肉桂精油和0.9%生姜精油配合1.0%的壳聚糖溶液和0.9%魔芋葡甘聚糖溶液制成的涂膜保鲜剂对冰鲜鸡的保鲜效果最好,能有效的使冰鲜鸡肉的货架期由原来的3 d延长至16 d。     

正交设计优化冷鲜鸡肉天然防腐剂保鲜工艺研究

对天然保鲜剂茶多酚、乳酸链球菌素(Nisin)、ε-聚赖氨酸(ε-PL)应用于冷鲜鸡肉保鲜进行了研究。通过单因素实验,以感官评价、TVB-N值、pH值和细菌总数为评价标准,分别得出三种保鲜剂的最佳抑菌浓度分别是0.20%、0.08%和0.04%,且每组单因素的贮藏时间均为8d。在此基础上对三者进行复合保鲜,通过正交实验,得到最佳保鲜工艺条件为:茶多酚浓度为0.20%、乳酸链球菌素(Nisin)浓度为0.07%、ε-聚赖氨酸(ε-PL)浓度为0.04%。在此保鲜条件下,冷鲜鸡肉贮藏时间可延长至12d。     

壳聚糖联合茶多酚对淮南麻鸭冷鲜肉的保鲜效果

以淮南麻鸭的后腿肉为实验材料,经过不同的保鲜液处理后冷藏,评定鸭肉冷藏过程中色泽、气味的感官变化,并测定其pH、挥发性盐基氮(TVB-N)含量、酸价等理化指标和细菌总数的变化,研究壳聚糖和茶多酚联合对冰鲜鸭肉的保鲜效果。结果表明,壳聚糖联合茶多酚对冰鲜鸭肉的保鲜效果优于单一保鲜剂,1%壳聚糖+0.3%茶多酚的复合保鲜剂可使冰鲜鸭肉的保质期比对照延长20d以上。     

生物保鲜剂结合气调包装对冷却猪肉品质的影响

以空气包装组为对照,在4℃冷藏条件下,研究了单一保鲜剂(ε-聚赖氨酸)和复合保鲜剂(ε-聚赖氨酸、壳聚糖、茶多酚)分别结合气调包装对冷却猪肉品质的影响。通过测定样品的菌落总数、理化等指标,评价两种保鲜方法结合使用的保鲜效果。结果表明:对照组货架期约为6d,经过ε-PL和复合保鲜剂浸泡处理的冷却猪肉货架期分别为10d和16d。生物保鲜剂结合气调包装能显著延长冷却猪肉货架期,其中,真空包装组比气调组的保鲜效果差;80%CO2+20%O2包装组抑菌以及延缓TVB-N上升的效果最佳,复合保鲜剂组在第20d时还没有超出鲜度标准,但对冷却猪肉色泽有一定的负面影响,且保水性较差;20%CO2+80%O2的抑菌效果在气调组中最差,但对猪肉的色泽有很好的保护作用,复合保鲜剂组保质期约19d;50%CO2+50%O2在抑菌效果、色泽保护以及保水性方面都有很好的效果。     

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.