紫贻贝磷脂的贮藏性能

对不同贮藏温度下紫贻贝磷脂含量及其组分的变化情况进行了研究。在30℃、4℃、-10℃、-20℃分别贮藏贻贝,随着温度的上升,磷脂含量的下降速度加快。对贮藏3d后的贻贝磷脂进行组分分析,磷脂各组分的相对百分比都发生了变化,并且随温度的升高PC的降解速度大大加快,所占的百分比快速下降,而LPC的比例有不同程度的增加。     

科技与学术动态

贻贝收获期正值高温季节。因其极易变质,鲜销受到地区限制,用一般方法速冻又会使贝肉起渣、发糊并失去原有风味。上海水产大学有关科技人员经过三年研究,终于突破了贻贝速冻保鲜的难题。他们针对贻贝肉蛋白质含量高的特点,确定采用蒸煮开壳快速冷却取肉——保鲜剂浸泡——速冻——包冰衣冻藏的保鲜工艺,在-18℃贮藏半年的贻贝肉,仍能保持原有的色泽、风味、质地和营养成分。     

三种解冻方法比较研究

本文以速冻悲崔贻贝为试验材料，对空气解冻，红外解冻和微波解冻等三种解决方法进行了比较研究。通过测定解冻至５℃所需的时间和解冻后产品的感官评价、ＴＶＢ－Ｎ值及还原糖含量等质量指标来进行分析比较。实验结果表明，从解冻时间和解冻后产品质量的角度来看，选择微波解波法较适宜。符合现代流水线生产的需要，可为水产品解冻生产实际提供指导和参考。     

贻贝

贻贝是软体动物门瓣鳃网丝鳃目的一付珍贵海产贝类,含有丰富的蛋白质、脂肪、肝醣等,营养价值高,可治人体虚弱,防佝偻病,干制品称“淡菜”,是宴会上的名菜。贻贝广布我国沿海,品种甚多,养殖主要品种有厚壳贻贝、翡翠贻只、紫贻贝等,南方多翡翠贻贝,北方多紫贻贝,厚壳贻贝从勃海、黄海到台湾海峡都有。贻只生长在潮流急畅而风浪不大的港湾或靠近外海处,海水比重1.009—1.031为好,贻贝适温范围广,2—30℃都能生长,垂直分布在干潮线以下一尺至数十尺深的水层中,如翡翠贻贝在水深2公尺至9公尺左右生长较好,紫贻贝自低潮线至水深近2尺以内较多,也有分     

紫贻贝人工育苗的新进展与存在问题

无产阶级文化大革命以来，毛主席的革命科研路线更加深入人心。几年来，我们在科研为无产阶级政治服务，与生产劳动相结合的方针指引下，与山东省胶南县有关单位一起，针对紫贻贝养殖发展中的苗种供应问题进行了一系列的试验研究。并已在紫贻贝幼虫、幼苗的生物学、生态条件与培养技术等方面取得了肯定的结果，使紫贻贝人工育苗提高到了中间生产规模。现将所得结果总结如下：     

氯硝柳胺和COS对紫贻贝的毒性作用机理

为研究氯硝柳胺和COS(一种树根中提取物)对紫贻贝抗氧化酶活性的影响,通过毒性试验的方法,测定紫贻贝组织的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、丙二醛(MDA)、胆碱酯酶(CHE)的酶活性。结果表明,紫贻贝组织内SOD和MDA的变化趋势是上升-下降, CAT和CEA的变化趋势是下降-上升-下降的趋势,由此可见,在两种药物胁迫下,紫贻贝机体虽没有出现死亡表现,但其机体内的酶活性含量已发生了显著的变化,可见这两种药物可能主要通过干扰紫贻贝机体应激机制来间接地造成氧化性损伤,最终导致紫贻贝死亡。通过对比两种药物对紫贻贝的四种生物标志物第10天的抑制率可知,氯硝柳胺对紫贻贝酶活性的敏感顺序为:MDASODCHECAT,COS对紫贻贝酶活性的敏感顺序为:CHESODCATMDA,可见紫贻贝组织中MDA和SOD酶对氯硝柳胺反应敏感,CHE和SOD酶对COS反应敏感。     

紫贻贝

名称、分类地位紫贻贝Mytilus edutis Linnaeus(以下简称贻贝)，属于瓣鳃纲，异柱目，贻贝科，贻贝属。地方名：海红、淡菜。     

紫贻贝和厚壳贻贝杂交及F1代杂交优势初探

2005-2007年对紫贻贝(Mytilus gallo provincialis)和厚壳贻贝(Mytilus coruscus)种间进行了杂交生产性试验,通过亲贝强化培育、确认雌雄亲贝、改革育苗水体交换方法、投喂混合单细胞藻类、流水培养附着稚贝等技术,获得F1代.结果表明,正交F1代幼虫的成活率明显高于反交F1代和厚壳贻贝,在幼虫培育前期与紫贻贝的成活率相当,但随着幼虫的发育有高于紫贻贝的趋势.正交F1代幼虫的壳长和壳高在培育阶段的前期生长与紫贻贝相当,低于厚壳贻贝,高于反交F1代;但后期的生长明显增快,并高于反交F1代和其他两种贻贝.各试验组贻贝海区养殖的成活率在90%以上,正交F1代最高,显著高于反交F1代.各试验组生长特性,正交F1代紫贻贝厚壳贻贝反交F1代.其中正交F1代获附着稚贝3.77×109 ind.正交F1除在孵化率上低于紫贻贝、厚壳贻贝外,在壳长、壳高、成活率等方面指标具有一定杂交优势,而反交F1代的杂交优势不明显.     

改善翡翠贻贝冻品质量的研究

本文研究了翡翠贻贝冻品在贮藏过程中的质量变化,从实验结果可得出：－２５℃的贮藏温度有效地保持翡翠贻贝冻品质量,如果再添加由８％多聚磷酸钠和１．６％六偏磷酸组成的复合添加剂,就可使其优秀品质保持期在７个月以上。     

杂交贻贝同工酶表达的初步分析

运用聚丙烯酰胺凝胶电泳技术,对2种贻贝(厚壳贻贝、紫贻贝)稚贝及通过人工培育所得的二者的杂交后代稚贝同工酶表达状况进行分析.结果显示,所检测5种酶(SOD、MDH、ME、ATP、ADH)在上述3种贻贝中的表达极为相似,MDH在3种贻贝中除r迁移率相同的条带外,在紫贻贝中表达出迁移率较小、表达较弱的条带;SOD和ATP仅在厚壳贻贝中表达出比另外2种多1条迁移率最大的条带,ME则表现为紫贻贝少1条中间的条带,ADH在杂交贻贝和紫贻贝中表达完全相同,厚壳贻贝虽也表现为3条酶带,但迁移率明显不同.试验结果说明,厚壳贻贝和紫贻贝具有较近的亲缘关系,其杂交后代与二者均有一定的相似性,这与传统的分类方法所得的结论相一致.     

Effects of postharvest processes on quality of Australian sardines (Sardinops sagax) and redbait (Emmelichthys nitidus nitidus) for feeding aquacultured southern bluefin tuna (Thunnus maccoyii)

Feed nutritional quality impacts on the performance of aquacultured species. This study was undertaken to assess the consequences of existing postharvest handling practices on nutritional quality of local baitfish (Australian sardines, Sardinops sagax and redbait, Emmelichthys nitidus nitidus) used to feed farmed southern bluefin tuna (Thunnus maccoyii). Controlled experiments were then undertaken to determine the most appropriate postharvest treatments to maintain baitfish nutritional quality, assessed through measurement of vitamins C and E, histamine, K value and TBARS. During frozen storage (?18 °C) vitamins and fish freshness decreased significantly and rancidity increased; after approximately 3 months baitfish were of questionable utility, particularly as a source of antioxidants. On‐land freezing method [i.e. block or individually quick frozen (IQF)] affected vitamin E loss with IQF sardines losing vitamin E faster than block‐frozen baitfish. Block‐frozen baitfish, particularly sardines, should be thawed in seawater, not air or freshwater, to minimize vitamin losses. Thawing time should be no more than 2 days, and baitfish storage less than 3 months. Thiobarbituric acid reactive substances (TBARS) correlated well with remaining vitamin E, indicating its usefulness as an indicator of antioxidant status. TBARS analysis is methodologically simpler, faster and cheaper than that for vitamins, and is therefore recommended for determination of baitfish nutritional quality.     

日本枪乌贼(Loligo japonica)不同温度冻藏过程中的品质变化

选取-20℃、-30℃和-50℃3个冻藏温度,以TVB-N值、肌原纤维蛋白含量、Ca2+-ATPase活性、巯基含量、TBARS值及肌肉组织微观结构为指标,结合感官评分,对比分析90 d内日本枪乌贼(Loligo japonica)的品质变化规律。结果显示,在不同冻藏温度下,随着时间的延长,Ca2+-ATPase活性和感官评分不断下降;肌原纤维蛋白和巯基含量,则先略微上升而后快速下降;TVB-N值和TBARS值呈不断上升的趋势,且温度越高上升速率越快;肌肉组织微观结构分析表明,枪乌贼肌纤维结构在冻藏过程中逐渐变得松散。相比-20℃,-30℃和-50℃冻藏温度条件下更能长久地保持枪乌贼品质,且品质无显著差异。综合分析认为,冻藏温度低于-30℃时,可较好地保持枪乌贼品质。     

上海市售扇贝冻品品质评价模型构建及关键影响因素分析.

为分析上海销售端扇贝冻品的品质状况及存在的问题,探究市售扇贝冻品的品质评价方法以及冻藏过程中导致其品质劣变的关键因素,本研究依据冰柜温度、冻藏时间、产品形式、包装方式和摆放位置共5种常见影响因素,对上海市售的11种扇贝冻品商品进行采样,测定白度、解冻损失、蒸煮损失、持水力、回复性、内聚性、弹性、咀嚼性、硬度和感官评分共10项品质指标,利用因子分析构建扇贝冻品品质评价模型,并结合多元线性回归分析确定影响扇贝冻品品质劣变的关键因素。结果显示,扇贝冻品10项品质指标之间存在一定相关性,通过因子分析提取了3个因子成分,累计方差贡献率为73.33%,可以代替原有指标来综合评价扇贝冻品的品质,建立了市售扇贝冻品的品质评价模型：f=0.467f1+0.302f2+0.231f3,其中,f1公因子包括弹性、回复性、内聚性、蒸煮损失和持水力,f2公因子包括硬度、白度和咀嚼度,f3公因子包括解冻损失和感官评分;进一步由多元线性回归分析得出,冻藏时间、冰柜温度和产品形式是影响扇贝冻品品质的关键因素,其他2种因素无显著影响。研究表明,基于因子分析和多元线性回归的方法能够较好地进行扇贝冻品的品质评价并分析导致其品质劣变的影响因素。     

Evaluation of Egg White Protein-Based Coatings to Improve the Protection of Frozen Atlantic Salmon (Salmo salar)

ABSTRACT

The effects of different egg white protein coatings on Atlantic salmon quality preservation after 4 months of frozen storage were evaluated. These coatings increased the yield of the fillets and protected them from lipid oxidation, providing better protection than glazing. Egg white protein coatings were better options than glazing to preserve salmon color during frozen storage. The best results were obtained with the application of coatings before freezing. No clear effects of the type and concentration of plasticizer in most quality parameters were found. Egg white protein + glycerol 2:1 applied before freezing was the best coating for frozen Atlantic salmon protection.     

Postmortem Changes in the Adductor Muscle of Scallop (Chlamys tehuelchus) in Chilled and Frozen Storage

Abstract

The effects of freezing and frozen storage on the biochemical properties of scallop adductor muscles stored at 2-4EC were investigated. Glycogen content fell 40% in the first 12 hr of chilled storage and decreased slowly thereafter. ATP content increased for a short time after death and then decreased slowly. Glycogen and ATP degradation was accompanied by a decrease in both pH and 260/250 absorbance ratio of scallop muscle extracts. A significant increase (p < 0.05) in the hypoxanthine (Hx) content was also observed in chilled stored adductor muscles. Adductor muscles showed a significant decrease (p < 0.05) in the 260/250 absorbance ratio of extracts and an increase in the Hx level after freezing. An increase in Hx content was observed during frozen storage of adductor muscles frozen immediately after processing. Expressible juice increased with freezing and frozen storage of the muscles. The results shown in this paper indicate a rapid loss of quality in scallop adductor muscles during storage at 2-4. Freezing and frozen storage enhanced the quality deterioration of the muscles.     

不同被膜对冷冻牡蛎质量的影响及优化

以提高冷冻牡蛎质量为目的，采用自行设计的冷冻装置，分别以魔芋葡甘聚糖被膜液、壳聚糖被膜液及葡甘聚糖和壳聚糖被膜液各为50％的复合液被膜牡蛎进行冷冻试验。采用正交实验，分析了不同方式处理对冷冻牡蛎质量的影响。结果表明，采用被膜液进行被膜可明显降低冷冻牡蛎VBN值和不合格率，提高冷冻牡蛎质量。在被膜液浓度相同状况下，魔芋葡甘聚糖被膜液被膜的效果最好。此外，还对牡蛎葡甘聚糖涂膜液被膜的状态参数进行了优化。     

Quality of Mince from Alaska Pollock (Theragra chalcogramma) Frames

The quality and frozen stability of minces produced from Alaska pollock (Theragra chalcogramma) frames were compared against commercially produced fillet mince. Fresh frame mince had a higher defect level, lower nutritional content, and darker color. Cooked frame mince had a softer texture than commercial mince. After 6 mo frozen storage, frame mince had deteriorated to where it had unacceptable color, flavor and cooked texture. Rancidity increased more rapidly in frame mince than commercial fillet mince. Blending frame mince at levels of 10% to 20% with commercial mince produced acceptable fresh quality but marginal frozen storage stability.     

The Effect of Prior Frozen Storage (−20°C) on the Quality of Oven-Baked Sardines (Sardina pilchardus)

ABSTRACT

The effect of frozen storage for 3, 30, 60, 90, and 120 days on the quality of sardines baked for 15, 30, and 45 min was studied. The combination of frozen storage with the baking time in linear reduction of yield and moisture led to less juicy products, as well as significant changes in proteins and lipids. A linear increase of C16:0 followed by a linear reduction of C22:6ω-3 was detected due to frozen storage, indicating lipid oxidation. This was also confirmed by the C22:6ω-3/C16:0 and C20:5ω-3/ C16:0 ratios, which were reduced by 36.8 and 32.7%, respectively. The fatty acid profiles of sardine samples were not significantly altered due to oven-baking. A gradual reduction of eicosapentaenoic acid + docosahexaenoic acid (EPA + DHA) of the baked products was observed mainly due to frozen storage. Cholesterol and squalene content increased with increasing the time of baking. A gradual decrease of cholesterol and squalene was observed due to frozen storage.     

低温速冻处理对养殖大黄鱼冻藏品质的影响

研究了养殖大黄鱼分别用-20℃空气冻结和-65℃低温速冻处理后,在-18℃冻藏过程中肌肉蛋白质生化特性、质构特性以及组织结构的变化情况。结果表明,无论是-20℃空气冻结还是-65℃低温速冻,随着贮藏时间的延长,养殖大黄鱼的盐溶性蛋白含量、Ca2+-ATPase活性、硬度均呈下降趋势,pH值先下降后上升。低温速冻处理冻结速率快,组织细胞产生的冰晶小且均匀,细胞形态基本保持完整,对盐溶性蛋白质含量和Ca2+-ATPase活性影响极显著(P0.01),低温速冻更有利于保持养殖大黄鱼的品质。     

3种淡水对虾在冻藏过程中蛋白质特性的变化

以目前市场上主要的3种养殖对虾为对象,以肌原纤维蛋白盐溶解度、Ca2+-ATPase活性与蛋白质表面的巯基含量为指标,探讨了不同温度冻藏过程(-10、-20、-30、-40℃)对虾虾肉蛋白质生物化学特性的变化,评价了不同冻藏温度对对虾品质的影响。结果表明,第一,3种蛋白质的冷冻变性指标应用于对虾时出现一定差异。Ca2+-ATPase活性比较灵敏,能较好反映-10～-40℃不同冻藏温度引起的蛋白质变性的程度。肌原纤维蛋白盐溶解度能够反映-20℃以上冻藏过程中蛋白质变性程度的差异,而-20～-40℃的差异难以区分。-10℃冻藏时,肌原纤维蛋白的盐溶解度下降明显,而-20℃冻藏时下降程度较小,-20、-30、-40℃冻藏时肌原纤维蛋白的盐溶解度没有明显区别。-10～-40℃冻藏对于巯基含量变化都不大。第二,冻藏过程中3种对虾蛋白质冷冻变性较轻度,比一般鱼类在冻藏过程中稳定,虾比大部分鱼类更耐冻。第三,冻藏温度越低Ca2+-ATPase活性下降程度越小,-10～-40℃冻藏时其差异性有比较明显区分,表明Ca2+-ATPase活性更适合于虾的质量评价。第四,-20℃冻藏对于虾类是比较经济合理的,实用冻藏温度可取-20℃...