共查询到20条相似文献，搜索用时 46 毫秒
1.
采用化学分析、质构检测及动力学模型建立等方法, 对凡纳滨对虾(Litopenaeus vannamei)即食虾仁在常温保藏中的细菌总数、TVB-N值、pH值、质构特性、色差值及感官评价等参数进行测定。以挥发性盐基氮TVB-N作为货架寿命的关键指示因子, 利用Arrhenius法预测常温流通高水分即食调味虾仁的货架寿命。计算结果Ea为65.26kJ/mol, k0为6.04×109, 进一步推算得到在20℃和25℃常温流通条件下, 即食虾仁产品的货架期为148.61d和94.1d。在25℃保藏3个月的虾仁虽在细菌总数、TVB-N值、pH值、感官评分、质构、色差值等方面均发生了一些变化, 但都在安全范围之内, 不影响其食用价值。本研究为常温流通的即食虾仁产品开发奠定了理论基础。 相似文献
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本文测定了海捕大管鞭虾(Solenocera melantho)(又称红虾)调理食品在不同温度保藏中的细菌总数、挥发性盐基氮(TVB-N)值、pH值及感官评价等参数。通过对虾肉色泽、组织质构、风味和外形四个方面的检测,综合各项指标决定将TVB-N作为该产品质量变化和推测货架期时长的关键指标。将各温度下测定的TVB-N值代入线性方程组计算出反应活化能E_a为55.21 k J/mol,指前因子k_0为1.08×10~9。利用Arrhenius方程外推法计算得出在20°C和25°C温度下TVB-N值变化速率常数分别为k_(20°C)=0.1405和k_(25°C)=0.2386,从而进一步确定该条件下保藏的理论货架期分别为153.6d和92.1d。经质构仪分析红虾虾仁的硬度与弹性变化,综合感官评定结果和其它测定值,确定海捕红虾产品在常温贮藏中的货架期为3个月。本研究为常温下红虾调理食品的保藏提供了理论依据。 相似文献
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低温贮藏罗非鱼微生物学质量变化特性和保藏期 总被引：14，自引：0，他引：14
进行了罗非鱼在0,5,10,15℃贮藏过程中的微生物学质量变化特性和高品质期、货架期的研究,并对其特定腐败菌假单胞菌、细菌总数、VBN与感官评价的一致程度进行了探讨。结果表明,罗非鱼在0～15℃温度区域是淡水鱼中鲜度下降慢的鱼种,在0,5,10,15℃贮藏中,罗非鱼的高品质期分别为11,6,3和1.5d,货架期分别为20,9.5,5和2.5d。高品质期和货架期终点的假单胞菌数平均为(6.27±0.23)Log10cfu·g-1和(7.70±0.11)Log10cfu·g-1,显示了假单胞菌计数与罗非鱼的感官鲜度及保藏期具有较可靠的一致性。高品质期和货架期终点的细菌总数平均为(6.84±0.60)Log10cfu·g-1和(8.08±0.41)Log10cfu·g-1,VBN值平均为(11.8±1.38)mg·100-1·g-1和(20.1±1.66)mg·100-1·g-1,均无显著差异(P>0.05),表明细菌总数和VBN作为罗非鱼低温贮藏的鲜度指标与感官鲜度评价有较好的一致性。 相似文献
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鲫鱼(Carassius auratus)在微冻保鲜过程中的质量变化 总被引：2，自引：0，他引：2
该文研究鲫鱼 ( Carassius auratus)在微冻 ( - 3℃ )保鲜过程中的质量变化规律。以感官评价、细菌总数、T- VBN值、p H值、ATPase活性、K值等作为质量指标。实验结果表明 ,微冻可以明显抑制细菌总数的增长 ,维持较低的 T- VBN和 K值。但是 ,微冻条件下鲫鱼的 ATPase活性下降速度较快 相似文献
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超低温冻藏对金枪鱼肉质构及生化特性机理研究 总被引：2，自引：0，他引：2
为探索金枪鱼肉冻藏过程中质构与生化特性变化规律,得到节能低耗的最佳冻藏温度,以黄鳍金枪鱼质构、盐溶性蛋白含量、K值、颜色(a值)、持水率等为指标,研究在不同冻藏温度下(–18,–25,–35,–45,–55,–65°C)冻藏6个月的质构与生化特性变化规律。结果表明:在不同温度下冻藏,肌肉的质构、肌原纤维蛋白的盐溶性含量、鲜度随着冻藏时间的延长,均呈下降趋势;而且质地的变化与肌原纤维中盐溶性蛋白含量的变化呈正向关系,冻藏温度越低,品质变化越小。冻藏温度对金枪鱼的质构、盐溶性蛋白含量、鲜度、颜色的变化均有显著性影响(P0.05)。但在超低温–55°C与–65°C冻藏180d,无明显变化。从低碳环保角度来看,采用–55°C冻藏180d可以最大限度地保持金枪鱼的品质。 相似文献
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南美白对虾冰温下菌相变化 总被引：4，自引：0，他引：4
通过测定南美白对虾的冰点,确定了南美白对虾冰温贮藏温度;分析了冰温贮藏条件下南美白对虾细菌总数的变化情况,并通过生化实验分离鉴定了生鲜状态和达到一级鲜度时南美白对虾的细菌菌相。结果表明,南美白对虾冰点为(-1.4±0.1)℃,冰温贮藏3d后细菌总数达到1.03×105,达到一级鲜度的细菌总数极限值;4 d后细菌总数达到1.75×106,到达货架期终点。生鲜南美白对虾的优势菌为Aeromonas spp.,Chromobacterium spp.和Photobacterium spp.;冰温贮藏条件下达到一级鲜度时,南美白对虾的特定腐败菌(specific spoilage organisms,SSO)为Shewanella spp.,Flavobacte-rium spp.和Acinobacter spp.。 相似文献
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为探究贮藏温度对中国毛虾品质的影响,通过感官评分,菌落总数和理化指标的测定,分析毛虾虾皮在不同贮藏温度下的品质变化。结果表明:25°C及37°C贮藏期间感官评分、亮度值(L*)显著下降,红度值(a*)、黄度值(b*)、菌落总数显著增加(P0.05),p H值先缓慢增加后趋于稳定,TVB-N和TBA值在贮藏前期均缓慢增加,后期增加显著。4°C贮藏下,感官评分缓慢下降,p H值、菌落总数基本不变,贮藏30 d后,L*、a*、b*、TVB-N及TBA值呈现显著变化(P0.05)。综合分析,不同温度对毛虾虾皮贮藏期的色泽、感官评分、TVB-N、TBA、p H值及菌落总数变化均有显著影响;毛虾皮在25°C和37°C下分别贮藏至15 d及9 d时,已严重发黄并产生异味,菌落总数均大于107CFU/g,已腐败变质。4°C下贮藏至60 d时毛虾虾皮仍未失去食用价值,说明低温能显著延长毛虾虾皮的贮藏时间。 相似文献
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水产品鲐鱼(Pneumatophorus japonicus)细菌多样性及优势微生物分析 总被引：2，自引：0，他引：2
为研究鲐鱼(Pneumatophorus japonicus)在不同冻藏时期的优势微生物,并且得到一个较全面的细菌群落组成结构,采用16SrDNA基因克隆文库及克隆子分析等方法,分别对冻藏1d、8d和20d条件下鲐鱼鳃体系中的细菌种群多样性、优势微生物及其中产组胺菌的变化进行分析。结果表明,不同时期鲐鱼鳃内的细菌多样性均较强;冻藏1天的鳃体系中不动杆菌属(Acinetobacter)占优势为总数的77.5%,产组胺细菌如泛菌属(Pantoea)和肠杆菌属(Enterobacter)较少;第8天优势细菌种群是梭杆菌属(Fusobacteria bacterium)和希瓦氏菌属(Shewanella),而产组胺菌如发光杆菌属(Photobacterium)和弧菌属(Vibrio)较前期数量有所增加;冻藏到第20天的优势种群为哈夫尼菌属(Hafnia)和沙雷菌属(Serratia),它们均是产组胺的菌群。鲐鱼中细菌多样性及其优势微生物的变化等全面信息可为了解鲐鱼水产品组胺发生的微生物机制及其控制方法提供重要依据。 相似文献
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以远洋鲣鱼为研究对象,以传统淡水碎冰保鲜为对照,研究流化冰处理对鲣鱼的理化性质及微生物特性的影响。结果表明:(1)–4°C冷藏18d后,流化冰保鲜鱼肉pH值、TVB-N、TBA、a*值和菌落总数依次为5.57、10.2mgN/100g、2.87mg/100g、8.92和2.61lgCFU/g,而淡水碎冰保鲜鱼肉各指标已达6.05、20.3mgN/100g、6.60mg/100g、7.16和3.02lgCFU/g,故可知流化冰保鲜处理效果明显优于碎冰保鲜。(2)在25±1°C室温条件下,将冰与鱼放入保温箱内保鲜8h后,流化冰保鲜鱼肉的a*值、pH值、TVB-N、TBA、菌落总数和汁液流失率均显著低于空白和淡水碎冰保鲜处理组(P0.05)。流化冰保鲜可显著减缓鱼体的腐败进程、延长产品货架期,进而满足冰鲜水产品的远洋及长距离运输要求。 相似文献
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在鱼鲜酱油的酿制中 ,研究鱼鲜酱油稀发酵中的糖量变化及其与曲霉生长活动的关系 ,对比了在发酵后期向发酵液中加入与不加入糖化液对曲霉生长活动和发酵效果的影响。结果表明 ,鱼鲜酱油稀发酵过程中仅消耗了以粗淀粉形式出现的糖量 ,在 35℃下 ,开始发酵的第 1天至第 4天为曲霉生长繁殖的高峰期 ,到第 1 3天曲霉活细胞数达到最大值 ,此后则开始衰退。第4天至第 1 0天为糖量消耗高峰期。而在发酵后期 (第 1 9天 )添加糖化液 ,在 32℃下发酵 ,可促使曲霉细胞二次活动高潮的形成 ,并使最终产品的无盐可溶性固形物、全氮及各项感官指标均优于未加糖组。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明：土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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Phylogenetic diversity and phenotypic characterization of cultivable bacterioplankton isolated from polar oceans 总被引：1，自引：0，他引：1
A set of 27 marine planktonic bacteria isolated from the polar regions was characterized by 16S rDNA sequencing and physiological and biochemical testing. More than half of these bacteria were positive for caseinase, gelatinase and 13-glucosidase, and could utilize glucose, maltose or malic acid as carbon source for cell growth. Twelve isolates expressed nitrate reduction activities. Except for one antarctic isolate BSwlO175 belonging to Actinobacteria phylum, these isolates were classified as γ-Proteobacteria, suggesting that γ-Proteobacteria dominated in cultivable marine bacterioplankton at both poles. Genus Pseudoalteromonas was the predominant group in the Chukchi Sea and the Bering Sea, and genus ShewaneUa dominated in cultivable bacterioplankton in the Prydz Bay. With sequence similarities above 97%, genus Psychrobacter was found at both poles. These 27 isolates were psychrotolerant, and significant 16S rDNA sequence similarities were found not only between arctic and antarctic marine bacteria （ 〉 99% ）, but also between polar marine bacteria and bacteria from other aquatic environments （ ≥ 98.8% ）, including temperate ocean, deep sea, pond and lake, suggesting that in the polar oceans less temperature-sensitive bacteria may be cosmopolitan and have a bipolar, even global, distribution at the species level. 相似文献
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The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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Sediment properties, such as water content and density, have been used to estimate the dry and wet weights, as well as the volume of sediment recovered and discharged, during benthic impact experiments conducted in the Pacific and Indian Oceans. The estimates show that the weights of dry (355-1332 t) and wet sediment (1651-4888 t) recovered during the experiments, are not only a function of the total duration and distance covered during the experiment, but also depend on water content and density of the sediment. Estimation of dry sediment and its volumetric ratio in the discharge, are key parameters for calculating the discharged volume. The estimated volume of wet sediment recovered (1427-4049 m 3 ) as well as discharged (2693-6951 m 3 ) during the experiments, provide important inputs to evaluate the sediment resettlement and migration. Using these estimates, the average depth of excavation on the seafloor, can also been calculated. However, the stages of sediment recovery and discharge are expressed differently in some of the experiments. In order to standardize these, different stages have been identified, and definitions of certain terms have been suggested, for use in the future. The methods of calculating different properties, as well as weight and volume of discharged sediment are described in the paper for use in other applications concerning deep-sea discharges. 相似文献