栅栏技术优化即食调味珍珠贝肉工艺的研究

文章运用栅栏效应的理论，确定了高水分型即食调味珍珠贝肉食品的制作工艺，分析了各种常见栅栏因子对制品感官品质及微生物的影响，优化前处理、烘干工艺、杀菌工艺、pH、水分活度（activity water，Aw）和低温处理等多种栅栏因子，形成有效防止制品腐败变质的栅栏模式。试验结果表明，原料前处理需用3％的食盐进行了清洗；采用0．15％柠檬酸溶液调节pH为5．6～5．7；贝肉调味后需经烫煮；产品水分含量45％～50％，Aw为0．88～0．90；产品真空包装，低温处理24h，再采用巴氏杀菌（80～85℃、30min），能较好地保持产品的品质和风味，延长保存期，保持珍珠贝肉特有的鲜味和营养价值，促进珍珠贝肉的开发利用。     

真鲷水分脱湿等温曲线和热力学性质的研究

研究了真鲷水分脱湿(解吸附)等温曲线的动力学特性、不冻结水和冻结点之间的关系以及热力学性质.研究采用水蒸汽压法和差示扫描量热法测定了真鲷各个处理条件下的水分活度、熔融热和冰点.实验通过GAB(Guggenheim-Anderson-de Boer)模型和BET(Brunauer-Emmett-Teller)模型对真鲷的水分解吸附等温曲线进行了拟合,确定了各参数间的拟合方程.实验发现,真鲷的水分解吸附等温曲线为Ⅱ型(S形),GAB模型和BET模型均具有较好的拟合度,R2分别为0.991 5(GAB模型,aw: 0.13～0.98)和0.982 5(BET模型,aw＜0.90 ).由拟合方程计算得真鲷的单分子层饱和水分含量分别为0.082 0 g/g 干基(GAB模型)和0.078 1 g/g 干基(BET模型).实验发现,真鲷中可冻结水含量与熔融热存在线性关系(R2 = 0.999 6),并计算得当熔融热(ΔH f)为0时,真鲷的不可冻结水水分含量为0.291 2 g/g干基.     

水分活度降低剂在半干鱿鱼制品加工中的应用

水分活度(Aw)与食品品质及贮藏性有着密切的关系,降低半干鱿鱼制品的Aw有利于保持其品质并延长保质期。为寻求有效降低鱿鱼制品水分活度的方法,采用Box-Behnken试验设计和响应面分析法,研究了丙三醇、海藻糖和柠檬酸等3种水分活度降低剂对半干鱿鱼制品水分活度的影响。结果表明:丙三醇、海藻糖、柠檬酸均能有效降低半干鱿鱼制品的水分活度,最佳组合为:丙三醇1.80%,海藻糖4.00%,柠檬酸0.40%,此时鱿鱼制品的水分活度为0.872。     

鱼在腌制过程中水份活度和有关参数的变化关系

本文研究了腌制鱼的水分活度(Aw值)变化及其与其他有关参数的关系。以鲳鱼作为试验原料,用混合腌渍法对鱼品进行不同时间的腌制,然后观察鱼体中水分活度、盐分含量和水分含量的变化情况,并进一步探索这些参数之间相互的变化关系。实验结果表明,鱼体中水分活度和水分含量的降低,盐分的增加均在开始腌制至18小时时为最快;18小时后变化缓慢;34小时后基本趋向平衡。实验表明,水分活度,盐分含量与水分含量之间存在简单的线性关系,因此在腌制过程中,测定出水分和盐分含量就可以计算出水分活度Aw值,从而达到控制鱼品质量的目的。此方法在提高鱼品的保藏效果上具有一定的实用价值。     

高水分扇贝调味干制品保质栅栏的模式及其强度

运用栅栏效应理论，设置多个强度缓和的保质栅栏的交互效应，阻止微生物的生长发育，避免了单一高强调防腐方法对产品感官质量等方面造成的不良影响，研究开发的高水分扇贝调味干制品在Ａｗ〉０．９０时，仍非制冷可贮，口感柔软，能充分体现扇贝的鲜美 风味，较好地保持了鲜品的色泽和外观，卫生安全性得到进一步保证，经济效益提高。本文探讨了高水分扇调味干制品的保质栅栏模式，着重对各栅栏因子的强度进行了选择。     

盐酸对早期断奶仔猪生长的影响

四川农业大学动物营养研究所冷向军、王康宁、杨凤等采用48头平均体重5．25kg的28±1日龄断奶杜×长大杂交仔猪，在玉米－豆粕型基础日粮(对照组)中分别添加1％NaHCO3、1％柠檬酸钠、0．6％HCl、1．2％HCl、2．4％HCl、2．4％HCl＋2．04％NaHCO3和2．4％HCl＋2．38％柠檬酸钠，以研究盐酸对早期断奶仔猪生产性能和体内酸碱平衡的影响。结果表明：在断奶后头2周内，0．6％HCl提高日增重6．2％(P＜0．10)，降低了腹泻率；2．4％Hcl降低日增重14．2％(P＜0．10)腹泻率有轻微增加，在其基础上添加2．04％NaHCO3或2．38％柠檬酸钠，日增重得到改善，柠檬酸钠效果优于NaHCO3；1％NaHCO3降低日增重11．3％(P＜0．10)，增加了腹泻率；2．4％Hcl使尿液PH值、[HCO3]－下降(P＜0．01)，尿中氨N含量和占总排泄N的比例上升(P＜0．05)，有代谢性酸中毒趋势，但这种酸中毒趋势可用添加NaHCO3或柠檬酸钠缓解；0．6％HCl和1％NaHCO3；1％柠檬酸钠对体内酸碱平衡没有影响，但1％NaHCO3和1％柠檬酸钠使尿液PH值上升(P＜0．01)，[HCO3]－上升(P＜0．05)，表现碱性尿液特征。试验表明在早期断奶仔猪饲粮中添加低剂量HCl（0．6％）可降低仔猪腹泻率，轻微提高增重，而大剂量HCl(2．4％)则影响体内酸碱平衡，降低生长性能。     

扇贝血细胞胞内酶活性的细胞学观察

分别对海湾扇贝、虾夷扇贝、栉孔扇贝的3种血细胞胞内酶：碱性磷酸酶(ALP)、过氧化物酶(POD)、酚氧化酶(PO)进行了免疫细胞化学研究，并对血细胞酶反应阳性率作了统计。结果表明，3种扇贝血细胞ALP阳性率相差不大，海湾扇贝为46．6％，虾夷扇贝为42．4％，栉孔扇贝为36．8％；3种扇贝血细胞POD阳性率相差较大，栉孔扇贝阳性率高达50．2％，海湾扇贝为44．2％，虾夷扇贝仅为17．2％。3种扇贝血细胞PO孵育反应后，由于海湾扇贝、虾夷扇贝PO反应活性很低，瑞氏染液复染后，无法区分阴性、阳性细胞。实验中仅对栉孔扇贝PO阳性率进行了统计，栉孔扇贝血细胞PO阳性率为39．3％。     

人工养殖施氏鲟肌肉、皮、鳍的一般化学组成及其营养价值

对人工养殖的施氏鲟肌肉、皮和鳍进行了营养分析，结果表明，肌肉、皮和鳍中粗蛋白含量分为19．60％，38．70％，24．70％；纯蛋白含量分别为16．40％，17．94％，15．90％；18种氨基酸含量分别为18．17％，33．67％，24．44％；其中必需氨基酸各占42．21％，20．04％，21．79％；水分含量各为74．36％，57．50％，58．71％；灰分含量各为1．53％，2．54％，16．48％；总脂肪含量各为4．57％，5．78％，0．05％；施氏鲟肌肉、皮和鳍中还含有丰富的矿质。     

养殖褐牙鲆细胞色素b基因序列的初步研究

对养殖褐牙鲆(Paralichthys olivacews)的线粒体DNACytb基因的部分序列进行测定，测得的目的DNA片段的长度为410bp，其A(104bp)、T(119bp)、C(117bp)、G(70bp)4种碱基平均含量分别为25．4％、29．0％、28．5％、17．1％。在28个褐牙鲆个体中共出现了3种单倍型。白化褐牙鲆出现的第1种和第3种单倍型个体数分别为10尾(占白化褐牙鲆样本数的如90．91％)和1尾(9．09％)；6尾黑化褐牙鲆均出现第1种单倍型(100％)；正常褐牙鲆出现的3种单倍型尾数分别为7尾(占正常褐牙鲆样本数的55．56％)、2尾(22．22％)和2尾(22．22％)；测得的序列与既知序列间在第6bp、第19bp和第402bp碱基处出现差异。由于褐牙鲆Cytb基因的高度同源性，研究其白化、黑化和正常状态时出现的序列差异，对于寻找褐牙鲆白化机理研究的分子标记意义重大。     

背角无齿蚌和褶纹冠蚌肌肉营养成分的初步研究

背角无齿蚌含肉率3．41％，肌肉水分含量79．68％，粗蛋白10．23％，粗脂肪1．30％，粗灰分1．71％，钙2．97毫克／克，磷1．12毫克／克；褶纹冠蚌含肉率4．25％，肌肉水分含量78．86％，粗蛋白11．21％，粗脂肪1．40％，粗灰分1．74％，钙3．91毫克／克，磷1．09毫克／克。     

虾夷扇贝质量参数的测定

测定了虾夷扇贝鲜贝柱，干贝柱等质量参数，并与栉孔扇贝，海湾扇贝的质量和进行了比较，证实虾夷扇贝生长快，个体大，鲜贝柱，干贝柱大而且出率高。     

大连沿海虾夷扇贝体内重金属含量研究与质量评价

用微波消解对大连沿海虾夷扇贝样品进行处理,电感耦合等离子体质谱法测定虾夷扇贝不同组织中重金属Pd、Cd、Hg、Cr、Cu、Zn的含量,同时对重金属含量进行质量评价。试验结果表明,Pd、Cd、Hg、Cr、Cu、Zn在不同海域虾夷扇贝中的含量相差较大,6种重金属的平均含量分别为0.488、2.924、0.047、1.394、2.152、36.08mg/kg,即ZnCdCuCrPbHg。虾夷扇贝不同组织蓄积重金属具有明显的差异性,闭壳肌中重金属Cd、Cu的含量显著低于其他组织,Zn的含量却高于内脏团,不同组织对Cr的蓄积程度差异较小。调查发现,虾夷扇贝中重金属Cd的含量较高,尤其内脏部分远超过我国无公害水产品中有毒有害物质限量,建议食用虾夷扇贝时去除内脏团。     

An Improved Process for Retort Cooking Atlantic Blue Crab

Abstract

Non-uniform steam distribution and large temperature differences are frequently found within the retort during pressure steam cooking of blue crabs. A precook treatment involving evacuation of air from the retort prior to introduction of steam was found to decrease this unevenness in temperature distribution. The conventional and modified treatments were compared by (1) determination of temperature profiles within a retort during the conventional cooking process and the modified process; and (2) testing the resulting product from the two processing methods for differences in meat moisture and pH. The modified process improved the temperature distribution and reduced cook time by up to 50%. Meat moisture content increased in crabs processed using the vacuum process while pH testing of the cooked meat showed little difference in meat from the two processes. It was concluded that the improved temperature distribution would shorten cook time and increase throughput, product yield, product safety, and process efficiency.     

中国对虾与海湾扇贝投饵混养的实验研究

用放在海水池塘中的8个陆基围隔(5.0m×5.0m×1.8m),研究中国对虾(Penaeuschinensis)与不同密度海湾扇贝(Argopectenirradians)投饵混养的放养方式、生产力和极限放养量.对虾体长(2.85±0.16)cm,扇贝壳长(1.10±0.12)cm,放养密度分别为6.0尾/m2和0,1.5,4.5,7.5粒/m2,用投饵和施肥(鸡粪和化肥)饲养.结果表明,扇贝密度为0和1.5粒/m2时,对虾的成活率无显著差异.混养(扇贝1.5粒/m2)时对虾的出塘体长、体重和产量分别比单养高2.5%,3.8%和6.5%;当扇贝密度高于1.5粒/m2时,对虾的平均体长、体重和产量随扇贝密度的增加而显著减少(P＜0.05).扇贝密度为1.5和7.5粒/m2时,其产量由470kg/hm2增至1236kg/hm2;当扇贝密度高时,去壳后湿重占体重的百分数从(42.84±3.44)%降至(37.88±4.26)%.扇贝的极限放养量为600～800kg/hm2,适宜放养密度为1.0～1.5粒/m2.     

Stress response and lipid composition in shrimp Litopenaeus vannamei fed diets enriched with squid or scallop viscera meal

We substituted 10% of fishmeal with scallop (Argopecten ventricosus) or squid (Dosidiscus gigas) by‐product meal in a feed for shrimp (Litopenaeus vannamei) growth assay that lasted 60 days and then shrimps were submitted to handling stress. Shrimp fed the control diet had smaller weight gain and lower recovery after stress. Prostaglandins in gills were affected by diet and stress, with significant differences in shrimp fed the control diet before and after the stress. Hydroperoxides were increased after stress, while isoprostanoids were higher in shrimp fed the control diet. The gene expression of Glutathione peroxidase and Catalase was increased on the stressed shrimp fed the scallop diet, with no differences among diets for Superoxide dismutase or Cyclooxygenase. Arachidonic acid in the phospholipid fraction of muscle was the only fatty acid affected by stress and diet. Cholesterol oxidation products were significantly higher in shrimp fed the scallop diet compared to shrimp fed the control diet before applying the stress. A PCA analysis grouped in one‐factor growth variables, as well as Superoxide dismutase, esterified astaxanthin and isoprostane, while another factor was determined by stress, prostaglandin and hydroperoxide levels in gills. The partial substitution of fishmeal with scallop of squid by‐product meals affected growth and stress differently, indicating shrimp that grew up more were not necessarily more tolerant to handling stress, which can have a strong repercussion in aquaculture, particularly during density control, recording of growth and harvest.     

Evaluation of hemato-immunological parameters during the reproductive cycle of the scallop Nodipecten nodosus in association with a carotenoid-enriched diet

The cultivation of scallops Nodipecten nodosus is a promising activity emerging in Brazil. The purpose of this study was to characterize the immune system of N. nodosus and evaluate the modulation of some hemato-immunological parameters during the reproductive cycle, in association with an astaxanthin-enriched diet. It was hypothesized that a supplementation on astaxanthin could enhance scallop immune system and minimize stress of reproduction. Scallops were separated in different groups: juveniles (J), adults (A), sexually mature (M), and recently spawned (S) animals. The last two groups were fed standard (M and S) or astaxanthin-enriched (Ma and Sa) diets. Scallop hemolymph contained two hemocyte populations: hyaline (HH) and granular hemocytes (GH). Antimicrobial peptides, similar to mussel defensins and mytilins, were found by immunodetection within the GH granules, even though the scallop hemolymph did not exhibit significant antimicrobial activity against different bacteria, including marine vibrios. Scallop hemocytes were able to phagocytose zymosan and produce reactive oxygen intermediates (ROI–NBT reduction). The number of circulating hemocytes (Neubauer chamber) varied from 12 to 26.10⁶ cells mL^− 1, and the GH was always the predominant cell type (67–99%). The plasma of N. nodosus contained lectins, specific to galactose and sialoconjugates, and their agglutinating activity was partially calcium-dependent. A phenoloxidase (PO) activity (146–446 U min^− 1 mg^− 1) was observed in the scallop hemolymph. However, this activity was not induced by trypsin or components of microorganism surface, and was strongly enhanced by alkaline pH (≥ 8.5). The total protein concentration of the plasma varied from 240 to 660 μg mL^− 1. In general terms, all examined hemato-immunological parameters (hemograms, superoxide anion production, PO activity, lectin titers and total protein concentration) had a similar profile during all the scallop reproductive cycle. Their levels increased significantly from juveniles to adults (except PO activity), and declined markedly (immune depletion) in the sexually mature scallops. After spawning, the animals had a tendency to recover the standard levels of their immune parameters. Apparently, the astaxanthin-enriched diet had no effect on the tested immune parameters except for a slight influence on the scallop immune-oxidative reactions (ROI production). The results obtained in this study suggested the occurrence of a general immune depletion in the sexually mature scallops, confirming that the reproductive stage is a critical period in scallop life.     

浮筏养殖虾夷扇贝的自然稀疏效应

为了研究虾夷扇贝浮筏养殖自然稀疏效应和科学养殖密度,2009年8月—2010年7月,对不同密度梯度的3个贝龄虾夷扇贝进行浮筏养殖现场实验。在自然稀疏条件下,逐月调查浮筏养殖不同贝龄的虾夷扇贝壳长生长、湿重增长和累计死亡率,并估算了适宜的扇贝浮筏养殖密度。结果表明,在不同养殖密度条件下,3 个贝龄扇贝周年壳长生长都没有显著差异;1龄贝壳长增长最快,年均增长29.53 mm;2龄贝壳长年均增长23.50 mm;3龄贝壳长增长较慢,年均增长15.47 mm;3个贝 龄扇贝周年湿重增长都没有显著差异,3龄贝和2龄贝湿重增长较快,3龄贝的年均增长约54.07 g,2龄贝的年均增长约37.80 g,1龄贝的年均增长约14.69 g;2 龄贝、3龄贝各养殖密度梯度之间累计死亡率都没有显著差异,3龄贝死亡率介于76.30%～83.33%,2龄贝死亡率介于88.89%～91.78%,养殖密度为150个/层的1龄贝与80个/层和50个/层的1龄贝累计死亡率差异显著。依据自然稀疏模型,浮筏养殖适宜密度3龄贝为4～5个/层;2龄贝为8～16个/层,1龄贝为29～124个/层。     

A comparison of larval production of the northern scallop,Argopecten purpuratus,in closed and recirculating culture systems

Northern scallop Argopecten purpuratus aquaculture relies on an efficient all year-round larval supply. Larvae are generally produced in closed aquaculture systems (CAS) using the batch techniques with periodical water changes. For instance, survival rates are greatly variable and can range from 0 to 80% making production of scallop larvae uncertain. The main goal of this study was to determine the feasibility of rearing scallop larvae in a recirculating aquacultural system (RAS), and secondarily to compare scallop larval growth rate and time length to reach the settling stage when reared with a traditional Chilean CAS technique and in a novel RAS technique in an industrial-like approach.Several batches of larvae were cultured in CAS and RAS. Larvae were fed on Isochrysis galbana cultured in 35-L tubular photobioreactors. Growth rates were significantly different (F_11,2840 = 274.66; p < 0.001). All scallop larvae cultured in CAS showed lower growth rates ranging within 4.49 and 7.30 μm day^?1 and protracted period of culture until settlement (at least 10 more culture days) than those reared in RAS (growth rates between 9.56 and 13.15 μm day^?1). However, final survival (from D-larvae until settlement) of larvae reared in CAS showed higher values than those values recorded for larvae cultured on RAS. Higher growth rates observed in RAS could be attributed to a reduction in daily manipulation of the animals and/or more feed availability as well as higher temperatures and a steady state conditions in water quality. Even though, the reduction in time for rearing larvae until settlement in RAS was high, the comparison between systems is more significant in view of the reduction in make up seawater from 100% of system volume (CAS) to less than 10% of system volume (RAS). Therefore, RAS was independent from daily water quality variation from natural seawater by increasing water retention time, and with that improve water quality steady state conditions. Results of this research show that a more efficient use of water and heating systems than generally used in the Chilean hatchery industry is achievable. This is an important result since it could lead to significant reductions in the cost of operating a scallop hatchery, however further work is required to accurately compare the two systems (CAS and RAS). The main result from this research is that scallop larvae can be cultivated using recirculating aquaculture systems (RAS) as a method to increase production. The information reported in this paper will be useful for the improvement of scallop larvae culture techniques under controlled conditions.     

Marine co‐product meals as a substitute of fishmeal in diets for white shrimp Litopenaeus vannamei improve growth,feed intake and muscle HUFA composition

Total replacement of fishmeal using marine co‐product meals in the diets for white shrimp Litopenaeus vannamei and its effects on growth, feed utilization and muscle HUFA and sterol composition were assessed in a 45‐day feeding trial with juvenile shrimp (0.32 g mean initial weight). Eight dietary treatments were tested: a control diet containing fishmeal (FM), a commercial shrimp diet as external reference and six diets where the FM in the control diet was totally replaced by pen shell scallop viscera (Pinna rugosa), squid viscera (Dosidicus gigas) or whole chub mackerel (Scomber japonicus) meals, produced by two methods: (i) cooking followed by grinding and drying and (ii) grinding followed by drying. Survival in all treatments was above 92%, except in the commercial diet (77%). The growth response, feed utilization and chemical composition of shrimp varied among the treatments and were affected in different ways by the by‐products and the meals preparation process. Growth and feed intake were significantly higher in shrimp fed diets containing cooked‐dried squid and pen shell scallop viscera meals, and whole mackerel meal produced by grinding followed by drying. Muscle fatty acid profiles were improved for human consumption when these ingredients were used, compared with the diets containing FM.