为实现南极磷虾油品质导向的高效制备,实验以全脂南极磷虾粉为原料,以豆油或中链甘油三酯作为载体助溶剂,采用协同超临界CO2萃取技术制备甘油三酯富集型油脂(一级油);再以萃取后的南极磷虾粉饼粕为原料,采用乙醇提取法制备磷脂富集型油脂(二级油).基于所得磷虾油的脂质组成、磷脂酰胆碱和磷脂酰乙醇胺的绝对含量为考察指标,优选了30％豆油作为载体助溶剂.结果发现,与无助溶剂组和乙醇助溶剂组相比,载体助溶剂(30％豆油)组的一级油提取率最高(37.68％±0.39％),其一、二级油的甘油三酯与磷脂可有效分离,且其多烯指数、致动脉粥样硬化指数和致血栓指数较低,分别为0.14±0.00、0.35±0.02、0.41±0.02和1.33±0.08、0.62±0.02、0.02±0.00.研究表明,分级制备的南极磷虾油在磷脂含量上差异显著,不仅丰富了磷虾油产品种类,也为后续南极磷虾油提取工艺的选择与制定提供理论指导.

以南极大磷虾酱料为研究对象,采用不同杀菌方式[紫外杀菌(UV)、微波(MV)、巴氏杀菌(LTLT)、高温杀菌(HTST)]对样品进行处理,通过分析南极大磷虾酱料的感官、质构、流变、色泽、风味等指标,结合微生物残存检测,探讨不同杀菌方式对酱料品质及安全性的影响.结果显示,南极大磷虾酱料整体风味独特,质感丰富,可接受度高.HTST组色泽变得深暗,嫩度降低,组织结构不均,滋味的甜度值减少,咸度值升高,气味品质受到破坏,综合感官评分较低.UV组在滋味和气味品质方面与CG组具有较小的差异性,L*值最高(28.97),质构分析中硬力值和硬力做功值分别为166.90 g和9.33 mJ,韧性较强,而组织结构均一性较差.MV组硬力值和硬力做功值分别为128.80 g和6.59 mJ,流变值为17.49 Pa·s,质构的剪切力变低,组织均一性良好,在滋味、气味和色泽品质上变化较小.LTLT组品质变化较小,具有较高的感官综合可接受度.南极大磷虾酱料灭菌后的细菌总数和大肠菌群数量均低于10 CFU/g,沙门氏菌和金黄色葡萄球菌均未检出.研究结果为南极大磷虾高值化产品的工艺优化、品质提升和综合利用提供基础数据.

为了拓展南极磷虾油的应用范围,采用喷雾干燥法制备南极磷虾油微囊粉.通过对比微囊化效果确定最佳壁材、乳化剂及工艺条件,并对最终产品各项性能指标进行测定.结果 表明,制备南极磷虾油微囊粉的最佳条件为:最佳壁材组合为麦芽糊精(75％)与酪蛋白酸钠(2％),最佳乳化剂为单甘酯,单甘酯添加量2.0％,均质压力40 MPa,喷雾干燥进风温度180℃、出风温度90℃.在最佳条件下制得的南极磷虾油微囊粉表面含油率为0.68％,包埋率达到95％以上,载油量约为20％.南极磷虾油微囊粉为淡红色,具有一定的虾油味道,流动性良好,没有出现结块现象,并且复水后能够快速溶解,没有分层或漂油现象.

为防止南极磷虾油在加工和贮藏过程中发生氧化,减少过程中氧化反应的发生,采用Schaal加速试验方法,以过氧化值(peroxide value,POV)为考察指标,研究在不同加工阶段添加维生素E、迷迭香提取物和茶多酚3种天然抗氧化剂对磷虾油抗氧化性能的影响,最终确定添加抗氧化剂的最佳阶段、种类和最佳添加浓度.结果表明,在虾油萃取阶段添加抗氧化剂的效果优于在成品油阶段添加抗氧化剂的效果,在虾油萃取阶段添加0.2％的天然VE抗氧化剂的抗氧化效果最好.所得结果将为虾油在生产和贮藏过程中的品质提升提供技术参考依据,具有重要的实际应用价值.

借鉴水化脱胶原理,对南极磷虾油磷脂富集工艺进行优化.通过单因素实验考察了反应溶液类型、质量分数、加入量,反应温度,反应时间及搅拌速度对南极磷虾油磷脂富集效果及富集后各功能成分的影响,得到南极磷虾油磷脂富集的最佳工艺条件为南极磷虾油中加入4倍南极磷虾油磷脂量的2％柠檬酸溶液、反应温度60℃、搅拌速度60 r/min、反应时间30 min.在最佳条件下磷脂富集效果明显,分离得到的磷脂溶液经冻干后磷脂含量可达70.78％,EPA和DHA含量分别为151.93 mg/g和113.70 mg/g;而分离得到的甘油三酯中虾青素含量最高可达780.49 mg/kg.

以磷虾油中的虾青素含量为评价指标,对浓缩工艺中加热温度、加热时间、真空度等浓缩条件进行考察,找到影响虾油中虾青素含量的关键因素,明确各因素对虾青素含量的影响大小,并结合生产实际,最终确定最佳浓缩工艺为真空度-0.1MPa,加热温度为50℃,加热时间为3h.

以南极磷虾为原料,采用柠檬酸钠溶液浸泡法从磷虾中提取磷虾油并对其工艺条件进行优化,以提取率、磷脂、酸值和流动性等衡量磷虾油生产成本和产品品质最重要的4个指标综合分析,确定最佳提取工艺条件:柠檬酸钠溶液浓度1.0％、料液比1∶5、浸泡时间3.0h.在此工艺条件下,采用95％乙醇浸提磷虾粉,固液分离后,对分离得到的提取液进行减压蒸馏,除去乙醇后得到的磷虾油的磷脂含量为50.15％、酸值为10.33 mgKOH/g,磷虾油的提取率为14.9％,并且流动性较好.该工艺操作简单,安全实用,提取出的磷虾油磷脂含量高、酸值低、流动性好、品质稳定,极大提高了南极磷虾的综合利用率,具有重要的实际应用价值.

食源性腐败菌是食品腐败的重要原因,它可通过初级或次级代谢产生具有异味的挥发性有机化合物(volatile organic compounds,VOCs),加速食品的腐败进程.腐败菌种类及组成会随食品基质和贮藏条件而改变,导致产生的VOCs也具有多样性和差异性.随挥发性有机物质收集和检测技术的快速发展,通过分析腐败菌相关的VOCs成分组成可鉴别食源性腐败菌种类和食物腐败进程.本文对常见腐败菌VOCs的产生途径和种类进行归纳,并重点探讨了VOCs提取分析技术及在食品腐败研究中的具体应用,为有效进行腐败菌防控,提升食品质量和安全提供参考.

为研究饲料脂肪水平对血鹦鹉幼鱼(Cichlasoma synspilum♀×Cichlasoma citrinellum ♂)肝脏免疫及抗氧化酶的影响,以豆油为脂肪源,配制5组粗脂肪含量分别为4.77％(CL1)、8.75％ (CL2)、11.68％(CL3)、16.25％ (CL4)、23.70％(CL5)的实验饲料饲喂血鹦鹉幼鱼.实验采用初始体重为(1.20 ±0.30)g的血鹦鹉幼鱼分5个不同脂肪饲料来饲养42 d,每组30尾.饲养6周后,无菌取其肝脏,制备组织匀桨液,测定其肝脏中免疫及抗氧化相关酶含量,包括碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、溶菌酶(LMZ)、超氧化物歧化酶(SOD)、总抗氧化酶(T-AOC)、过氧化氢酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)和丙二醛(MDA).实验结果表明,饲喂不同饲料脂肪水平的血鹦鹉幼鱼肝脏免疫及抗氧化相关酶活力均呈现先升高后下降的趋势;在饲料脂肪水平为11.68％时,LMZ、SOD、T-AOC、GSH-Px活力最高且显著高于其他脂肪水平组(P＜0.05);当脂肪水平为16.25％时,AKP、ACP、CAT活力、MDA达到最大值并显著高于其他饲料组(P＜0.05).通过绘制二次曲线回归方程得知血鹦鹉幼鱼最适饲料脂肪水平为15.80％-16.75％.本研究将为血鹦鹉幼鱼实用饲料营养的精准供给提供理论基础.

The invention relates to a method for extracting euphausiid oil with a low acid value, low protein content and low salt content from euphausiids under mild conditions. The method comprises the steps of mixing euphausiids and an organic extracting agent according to the proportion of (1:3.5)-(1:15), stirring and extracting at the temperature of 10 DEG C below zero to 75 DEG C for 0.5-5h, and then, separating residues to obtain an extraction liquid; directly adding water into the extraction liquid, or firstly concentrating the extraction liquid at the temperature of 30-70 DEG C, then, adding water into the concentrated extraction liquid until the water content is up to 10-80% to realize oil water phase separation, collecting an oil phase, and distilling at the temperature of 30-70 DEG C to obtain a finished product of the euphausiid oil. The method is simple in process flow, free of complex equipment, flexible in site selection, mild in condition and free of damage to bioactive substances such as astaxanthin and the like when impurities such as free fatty acids, salt, proteins and the like are removed, so that the quality of the euphausiid oil is greatly improved.

The invention discloses a method for preparing antarctic krill low-fluorine hydrolysis polypeptide. The method comprises the following steps of: performing enzymolysis on antarctic krill powder used as raw materials, heating and inactivating enzyme, centrifuging, adding calcium oxide at different concentration, defluorinating, uniformly stirring, performing centrifugal separation, adjusting a solution until the solution has a certain pH value, and performing spray drying on supernatant obtained through separation to obtain the antarctic krill low-fluorine hydrolysis polypeptide of which the fluorine content is 10 to 30ppm. The process is easy to operate, the obtained product has low fluorine content, the nutrition constituents are damaged slightly, consumed time is short, and the process is simple and efficient, and is an ideal method for removing fluorine from enzymatic hydrolysate. The method lays the foundation for developing the multi-functional antarctic krill low-fluorine polypeptide.

Using whole cells as antigens, specific egg yolk antibodies (IgY) were generated respectively against Shewanella putrefaciens and Pseudomonas fluorescens, two important spoilage bacteria in aquatic products. The obtained IgY exhibited a high and specific affinity to corresponding antigen bacteria. A concentration-dependent antimicrobial activity of the specific IgY was observed in liquid medium. Compared to control groups, the cell number of S. putrefaciens and P. fluorescens was reduced approximately 84.7% and 88.1%, respectively, in the presence of specific IgY (contain salts) at a concentration of 200 mg/mL after 8 h of incubation. Similar growth inhibitory effects were also observed in solid medium, in which the inhibition ratio was calculated as 52.8% and 62.5% for S. putrefaciens and P. fluorescens, respectively, in the presence of specific IgY at a concentration of 100 mg/mL. These results indicated a great potential of specific IgY as a safe and natural antimicrobial agent for aquatic food preservations.

Disclosed is a method for extracting phospholipid-rich krill oil from Antarctic krill. The method includes using the Antarctic krill or Antarctic krill head shells as raw materials, subjecting the raw materials to pretreatment such as heating for enzyme-killing and sterilization and alkaline solution soaking, performing water removing, drying and smashing, using organic solvents to extract krill powders, performing filtering, subjecting separated extracting solutions to rotary evaporation, and removing the residual organic solvents to obtain the Antarctic krill oil with phospholipid contents over 40%. The method for extracting the phospholipid-rich krill oil from the Antarctic krill is simple in operating, the obtained phospholipid-rich krill oil is cheap, safe, environment-friendly, high in the phospholipid contents, low in acid values and good in liquidity, and the method is capable of improving stability of the phospholipid oil, improving qualities of the phospholipid oil and greatly improving comprehensive utilization rate of the Antarctic krill and can be used as a simple and practicable method for extracting oil and particularly the phospholipid-rich oil from the Antarctic krill.

The egg yolk immunoglobulin (IgY) now receives increasing attention as a natural and safe alternative of chemical antimicrobial agents. To find suitable synergetic factors of this immunoglobulin, here the effect of metal ions, chitosan and potassium porbate on the antimicrobial activity of specific IgY against Pseudomonas taetrolens was investigated. Appropriate levels of Mg2+, Ca2+, K+ were able to enhance the activity of the IgY to inhibit the growth of Pseudomonas taetrolens in solid medium, however, only K+ and Ca2+ exhibited similar synergetic effects in Paralichthys olivaceus samples. Chitosan demonstrated no effects on IgY in culture media, but when used in the fish, the antimicrobial activity of the IgY was significantly increased in the presence of chitosan. Both in medium and fish samples, a significant synergistic effect of potassium sorbet was validated on the IgY in inhibiting the growth of Pseudomonas taetrolens. These results allowed us to suggest chitosan and potassium as promising synergetic factors of specific IgY for food preservation.

BACKGROUND: The spoilage of fishery food has been attributed to limited types of microorganisms called specific spoilage organisms (SSO). Unlike traditional food-preserving techniques which usually exploit broad-spectrum antimicrobial agents, here, based on the specific antimicrobial activity of egg yolk antibodies (IgY) against two SSO in refrigerated fish (Shewanella putrefaciens and Pseudomonas fluorescens), a novel strategy for fish preservation was suggested and evaluated.RESULTS: During storage of Paralichthys olivaceus fillets at 4 +/- 1 degrees C, the bacteria growth (including total microorganisms and the two SSO) in test groups was significantly inhibited in comparison to that of controls (P < 0.05). This antibacterial activity of the specific IgY was also confirmed by chemical analysis (pH, total volatile base nitrogen and 2-thiobarbituric acid value) and sensory evaluation, and the shelf life of samples was extended approximately from 9 days to 12-15 days in the presence of the specific IgY.CONCLUSION: These results indicated a significant antimicrobial activity of the anti-SSO IgY for refrigerated fish products, which allowed us to suggest its potential as a bio-preservative for seafood. (C) 2011 Society of Chemical Industry

The dominant spoilage organisms in cultured Paralichthys olivaceus during cold storage at 4 ℃ were qualitatively and quantitatively investigated. Based on the colony morphology, biochemical and physiological characteristics, spoilage bacteria were isolated at the end of shelf life and identified using bacteria identification systems. Shewanella putrefaciens was dominated spoilage bacteria, which accounted for about 58.4% of all bacteria at the end of shelf life at 4 ℃. Pseudomonas which were common spoilage bacteria in aquatic products included Pseudomonas fluorescens, Pseudomonas taetrolens and Pseudomonas marginalis,with a corresponding proportion of 63.2%, 29.2% and 7.6%, respectively. Two types of egg yolk antibodies (IgY) against Shewanella putrefaciens, Pseudomonas fluorescens and Pseudomonas taetrolens were obtained by immunizing leghorn chicken by two methods, and their antibacterial efficiencies in liquid and solid media were evaluated. After incubation for 8 h in liquid culture, the inhibition ratio of the two IgYs at 100 mg/mL against antigen bacteria could attain between 61% and 78%, and after incubation for 24 h in solid culture, the inhibition ratio could reached between 27% and 40%. This demonstrates the potential application of egg yolk antibody as a natural antimicrobial agent for preservation and bacteria inhibition.

Dot-immunogold filtration assay (DIGFA) is a rapid and simple immunoassay for qualitative screening of analytes, but now its application is often restricted by relatively low sensitivity. Here, a secondary antibody-based method was developed to activate nitrocellulose membranes and therefore improve the sensitivity of DIGFA. With such activated membranes, the detection sensitivity for enrofloxacin was improved approximately five times in pure matrix. The same enhancement of DIGFA was also obtained with food samples. These results allowed us to suggest a promising application of the established technique for development of more sensitive DIGFA for low molecular contaminants in food.

采用5%NaOH、0.15 mol/L NaCl、0.1 mol/L磷酸盐缓冲液、0.15 mol/L NaCl及0.06%纤维素酶和1%SDS溶液提取新鲜海带中的蛋白质,并采用Brrddford的方法测定提取的蛋白质含量.结果表明,采用5%NaOH+0.06%纤维素酶浸泡,然后经超声波破碎,离心取上清液进行100%饱和度的(NH4)2SO4沉淀,对所得沉淀透析后冻干所得海带蛋白质的含量较多.时间飞行质谱表明蛋白质分子量为872～7705 m/z.抑菌试验表明海带蛋白对大肠杆菌、产气杆菌、金色葡萄球菌具有抑制作用.同时,以海带蛋白(5 mg/kg)对高血压模型大鼠灌胃具有良好的降压作用.