鳕鱼皮胶原蛋白肽的功能特性及抗氧化活性

以鳕鱼皮胶原蛋白肽为实验材料,研究其吸水性、保水性、乳化性等功能特性,并且进行了体外抗氧化实验。结果表明鳕鱼皮胶原蛋白肽具有较好的吸水性、保水性、吸油性和起泡性,具有一定的乳化性和较弱的泡沫稳定性。体外抗氧化实验结果显示,鳕鱼皮胶原蛋白肽对DPPH自由基、羟自由基和超氧阴离子自由基均有一定的清除效果,且清除率与样品溶液的浓度存在剂量依赖关系;浓度为30mg/mL时,胶原蛋白肽对DPPH·、·OH和O2-·的抑制率分别可达到73.84%、85.76%、64.09%。分级后,分子量1ku以下的胶原蛋白肽对DPPH·和·OH的清除能力最强,30mg/mL时清除率达到84%和90.97%;分子量5ku以上的胶原蛋白肽对O2-·清除能力最强,30mg/mL时清除率达到74.02%。     

仿刺参冷风干制工艺优化及不同干制方式的比较

以盐渍仿刺参为研究对象,以感官评分和脱水速率加权后的综合评分作为评价指标,采用单因素试验及响应面法对冷风干制(cold-air drying,CAD)工艺条件进行优化,并对CAD、真空冷冻干制(vacuum freeze drying,VFD)、热风干制(hot-air drying,HAD)和真空微波干制(vacuum microwave drying,VMD)工艺处理的仿刺参进行品质比较分析。结果表明:CAD最佳干制工艺条件为真空脱盐时间4.2 h、冷风温度19℃、冷风风速1.70 m/s,仿刺参的综合评分为0.77。在营养保持方面,VFD和CAD比HAD和VMD效果更好;在热收缩率方面,HADVMDCADVFD,其中CAD和VFD差异不大;在复水倍数方面,CADVFDHADVMD;在质构特性上,CAD和VFD质构指标明显优于HAD和VMD。对比结果说明CAD在工业生产中具有更高的实用性。     

Sensitivity of tag-recovery mortality estimates to inaccuracies in tag shedding,handling mortality,and tag reporting

We used Monte Carlo simulations to evaluate the sensitivity of tag-recovery mortality estimates to inaccuracies in tag shedding, handling mortality, and tag reporting. The data-generating model used in the simulations assumed that tagging was conducted annually for 4 years with tag recoveries occurring over a 4-year period. Several different combinations of instantaneous fishing (F) and natural (M) mortality were evaluated in the simulations. The data-generating model additionally assumed that immediate-shedding and handling-mortality rates equaled 2.5% and 0%, respectively, and that chronic shedding was a sigmoidal function of months since tagging. Two spatial patterns of reporting rates were considered—one where reporting was a function of distance from the tagging site and one where reporting was a random generation across the study area. Maximum likelihood estimates of F and M were calculated from the recovery of tags from the data-generating model under different assumed rates of tag shedding, handling mortality, and tag reporting. We found that assumptions about reporting rates resulted in the most variability in mortality estimates regardless of which combination of F and M was evaluated, with assumptions about chronic shedding also contributing substantially to overall variability in mortality estimates for most mortality combinations. Assumptions about immediate tag shedding and handling mortality had relatively minor effects on mortality estimates compared to reporting rate. When planning a tag-recovery study, care should be taken to ensure that chronic shedding and tag-reporting rates are accurately measured, as inaccurate measurements in these factors can result in significant errors in mortality estimates.     

凡纳滨对虾的加工利用和产业发展概述

凡纳滨对虾是当今高产的三大养殖对虾品种之一,具有广温广盐杂食性、生长速度快、抗病抗逆力高、适应性能强、营养需求低等突出特点,是一种营养均衡的食源性高蛋白佳品。凡纳滨对虾从1988年引进中国后,90年代初养殖获得成功,2000年后进行了规模化推广,2019年养殖总产量为181.6万吨t,逐步成为我国对虾养殖的主要品种和渔业经济的重要支柱产业,并且形成了从引种、繁苗、养殖、加工、销售等环节的庞大产业链,产生了巨大的经济效益、社会效益、生态效益以及文化效益。目前我国对虾加工产业处于结构简单、粗放加工的初级阶段,加上国际贸易壁垒、国内外市场低迷、成本过高等诸多因素,进行虾类高值化产品研究、加工技术研究、延长虾类加工产业链等已成为产业发展方向,这对开辟凡纳滨对虾加工食品新途径、促进虾产业的可持续发展具有重要意义。     

超高效液相色谱-串联质谱测定水产品中的己烯雌酚

建立了水产品中己烯雌酚(DES)的超高效液相色谱串联质谱(UPLC-MSMS)检测方法。样品经乙酸乙酯提取后,经正相固相萃取小柱净化,进行UPLC-MSMS分析。当添加水平在0.1～1.0μg/kg时回收率大于75%,相对标准偏差为7.2%～9.2%。     

Risk assessment in service provider communities

Online service delivery undertaken between clients and service providers often incurs risks for both the client and the provider, especially when such an exchange takes place in the context of an electronic service market. For the client, the risk involves determining whether the requested service will be delivered on time and based on the previously agreed Service Level Agreement (SLA). Often risk to the client can be mitigated through the use of a penalty clause in an SLA. For the provider, the risk revolves around ensuring that the client will pay the advertised price and more importantly whether the provider will be able to deliver the advertised service to not incur the penalty identified in the SLA. This becomes more significant when the service providers outsource the actual enactment/execution to a data centre — a trend that has become dominant in recent years, with the emergence of infrastructure providers such as Amazon. In this work we investigate the notion of “risk” from a variety of different perspectives and demonstrate how risk to a service owner (who uses an external, third party data centre for service hosting) can be managed more effectively. A simulation based approach is used to validate our findings.     

Effect of cooking methods on bioaccessibility of Zn,Se, Cd,Cu in sea cucumber (Apostichopus japonicus)

Food Science and Biotechnology - In this study, the total concentration and bioaccessibility of four metals (Zn, Se, Cd, Cu) in sea cucumbers (Apostichopus japonicus) before and after cooking were...     

凝胶渗透色谱净化-气相色谱-质谱法测定水产品中的溴酚类化合物

建立了水产品中溴酚类化合物的气相色谱-质谱分析方法。样品中的溴酚类化合物经酸化后,用正己烷-乙醚混合溶液提取,凝胶色谱净化,乙酸酐衍生后,用正己烷提取衍生产物,在选择离子模式下用气相色谱-质谱法进行测定。结果表明,溴酚类化合物在DB-17ms色谱柱上得到良好的分离,色谱峰出峰尖锐,没有杂峰干扰。乙酸酐衍生后极大地提高了溴酚类化合物在检测器上的响应,灵敏度也较衍生前提高近百倍。本方法检出限为0.3～0.5 μg/kg, 在添加浓度为0.3～5.0 μg/kg范围内,回收率为70.2%～102%,相对标准偏差为5.2%～10.3%。通过对市场上常见的水产品进行分析,发现溴酚类化合物的含量在0.56～4.44 μg/kg之间,其中2,4,6 三溴苯酚的含量最高。     

HPLC测定水产品中孔雀石绿、亚甲基蓝、结晶紫及其代谢物的残留量

采用固相萃取-高效液相色谱分析水产品中孔雀石绿及其代谢物(隐色孔雀石绿)、亚甲基蓝及其代谢物(天青A、天青B、天青C)、结晶紫及其代谢物(隐色结晶紫)。样品用乙酸铵缓冲液和乙腈提取,二氯甲烷初步净化后,再经MCAX固相萃取柱净化,以乙腈和0.125mol/L乙酸铵溶液为流动相,经MG C18柱分离后紫外检测器检测。孔雀石绿、隐色孔雀石绿、结晶紫、隐色结晶紫、天青B的定量限均为2.0μg/kg,亚甲基蓝、天青A、天青C的定量限均为5.0μg/kg。孔雀石绿及其代谢物和结晶紫及其代谢物、天青B添加2～40μg/kg,亚甲基蓝、天青A、天青C添加5～80μg/kg水平时,平均添加回收率大于70%,相对标准偏差小于15%。     

加工水产品中N-亚硝胺的形成和控制技术研究进展

N-亚硝胺类化合物(N-nitrosamines, NAs)是食品和自然环境中普遍存在的致癌物。一些水产品在加工贮藏过程中自身组分受不同因素作用,容易产生并积累NAs,个别情况下其含量会明显超出我国食品中污染物的限量标准,长期过量摄入含有NAs的水产品有致癌风险。因此,明确NAs的前体来源和影响因素,并在水产品加工、贮藏过程中控制NAs的产生和发展,对促进水产品加工行业健康发展、保障水产品食用安全有着重要意义。本文综述了水产品中NAs及其前体的来源和影响因素等关键问题,在总结前人研究工作的基础上探讨可能应用于水产品的NAs阻断控制技术,以期为控制加工水产品中的NAs提供参考。