超声波辅助酶法脱除石莼水溶性膳食纤维中蛋白质的工艺研究

本试验以蛋白质脱除率和水溶性膳食纤维(SDF)保留率作为指标,探讨各主要因素对石莼SDF脱蛋白效果的影响,并采用L_9(3~4)正交试验确定超声波辅助酶法脱蛋白的优化工艺参数。结果显示:在控制石莼SDF浓度0.6%和超声功率200 W的前提下,石莼SDF的超声波辅助酶法脱除蛋白优化工艺参数组合为:碱性蛋白酶使用量1 400 U/g、石莼SDF样液pH 11.0、超声温度50℃、超声时间1.5 h,以上述条件进行验证性试验,石莼SDF的蛋白质脱除率为(83.91±0.18)%,SDF保留率为(86.23±0.25)%,蛋白质脱除效果优于正交试验9个处理组。     

超声波辅助提取泥鳅多糖的工艺优化

以泥鳅为原料,采用超声波辅助技术提取泥鳅多糖,运用硫酸-苯酚法检测泥鳅多糖的含量,利用单因素试验结果设计正交试验,探讨料液比、超声时间和超声功率对泥鳅多糖提取率的影响。经工艺优化,获得超声波提取泥鳅多糖的最佳工艺为料液比1∶20、超声时间20 min、超声功率100 W,在最佳工艺条件下提取泥鳅多糖提取率最高,达到2.79%。     

响应面法优化武昌鱼鳞脱钙工艺的研究

以脱钙率为指标,以脱钙时间、盐酸浓度、液料比为自变量分别进行单因素试验,并在此基础上进行三因素二次旋转正交试验,对盐酸脱除武昌鱼(Megalobrama amblycephala)鱼鳞中钙质的反应规律进行了探讨。结果显示:液料比对脱钙率的影响最大,盐酸浓度次之,脱钙时间的影响最小。得出其反应模型及较佳脱钙工艺参数为:脱钙时间为86.01 min,盐酸浓度为0.43 mol/L,液料比为62∶1,脱钙率达到79.18%。     

微波辅助碱法提取匙吻鲟软骨蛋白-多糖复合物的工艺

以匙吻鲟软骨为材料,利用微波辅助稀碱法提取软骨中的蛋白-多糖复合物,在对碱浓度、微波功率、微波时间和液料比进行单因素试验的基础上设计正交试验,优化提取条件。结果表明,在液料比为15∶1(V/W),碱浓度为0.9%,微波功率为360 W,微波处理为9 min时,得率达到最优值15.72%。与常规碱法提取相比,微波辅助提取不仅降低了碱用量,更加环保,而且缩短了提取时间,提高了得率。     

甲壳素、壳聚糖生产工艺研究

本文以虾壳为原料探讨了甲壳素、壳聚糖的最佳提取工艺。试验中利用稀氢氧化钠溶液除去虾壳中的粗蛋白质,稀盐酸溶液除去虾壳中的灰分,并通过单因素试验得出制备甲壳素的最佳工艺条件为:先用5.0%氢氧化钠溶液脱粗蛋白质,处理时间5h,然后用5.0%盐酸溶液脱灰分,处理时间3h,循环处理直至加酸无气泡产生,甲壳素得率为6.0%,色泽白度为50.3,灰分为2.0%。通过正交试验探讨出甲壳素脱乙酰制备壳聚糖的最佳条件为:氢氧化钠溶液浓度50%,温度90℃,时间12h,料液比1∶70。壳聚糖脱乙酰度(D.D%)为84.8%,粘度(浓度1%)为38.3mPa.s。     

罗非鱼鱼皮提取明胶的酶法脱脂工艺研究

用脂肪酶对罗非鱼鱼皮进行酶法脱脂工艺研究。通过单因素与正交试验确定最适的酶法脱脂工艺为:pH值9,脱脂时间3h,酶添加量2%,料液比1:4,温度40℃,该工艺的脱脂率可达67.5%。通过超声波辅助脱脂研究表明其脱脂率并无明显的提高。     

凡纳滨对虾下脚料生产甲壳素过程中盐酸的循环利用

为减少甲壳素生产过程中废酸液对环境的污染,降低甲壳素的生产成本,试验以甲壳素生产过程中的废盐酸为研究对象,利用硫酸和氯化钙反应进行回收、循环利用盐酸溶液,通过单因素试验和正交试验对工艺条件进行优化。结果表明,脱钙废盐酸溶液最佳再生条件:反应温度为室温,硫酸质量分数为98%,硫酸与废盐酸中钙离子的摩尔比为2.3∶1,反应时间13 min,静置时间3.5 h,最佳条件下盐酸再生率为91.51%。利用最佳工艺条件对废盐酸进行再生处理,盐酸可循环重复利用5次,脱钙虾壳的碳酸钙残留量≤1.2%。     

超声波法制备高黏度的壳聚糖

以甲壳素为原料,用超声波法制备高黏度的壳聚糖。研究超声波的温度、超声的时间以及制备壳聚糖时浓碱的浓度3个不同条件对壳聚糖黏度的影响。结果表明,用超声波制备高黏度壳聚糖的最佳反应条件是:反应温度为50℃,反应时间为3 h,NaOH溶液的浓度为50%,可以得到黏度为2886.7mpa.s、脱乙酰度达97.17%的壳聚糖。将得到的高黏度壳聚糖制成膜,用于染料废水的处理,15 h后,壳聚糖膜对活性橙的脱色率就可达到99.5%。     

舌状蜈蚣藻蛋白质的提取及其抗氧化活性研究

该研究以舌状蜈蚣藻(Grateloupia livida)为原料,以蛋白质提取率为指标,探究不同破壁技术对舌状蜈蚣藻蛋白质的提取效果,并通过单因素分析和正交试验对超声波辅助水提法进行工艺优化,所得蛋白质经硫酸铵盐析法粗提纯后考察其体外抗氧化能力。结果显示,溶胀法、反复冻融法、珠磨法的最高蛋白质提取率分别为(29.66±0.86)%、(24.52±0.04)%、(26.52±0.79)%,均低于超声波辅助水提法;超声波辅助水提法提取舌状蜈蚣藻蛋白质的最佳工艺为:液料比160 mL·g^?1,超声全程时间60 min,超声功率1440 W,pH 6.0,此条件下蛋白质提取率可达58.16%;舌状蜈蚣藻粗蛋白质量浓度在1~8 mg·mL^?1内均具有较强抗氧化活性,其质量浓度为8 mg·mL^?1时的还原力为0.43±0.01,对1,1-二苯基-2-三硝基苯肼(DPPH)自由基的半数清除浓度(IC50)为4.00 mg·mL^?1,对2,2'-二氮-双(3-乙基苯并噻唑-6-磺酸)(ABTS)自由基的IC50为3.96 mg·mL^?1。     

真空微波膨化即食海带脆片工艺研究

为了研究新型即食海带脆片产品的加工工艺,采用盐渍海带为原料,对真空预干燥的海带进行微波膨化加工工艺优化。结果表明:海带规格(长×宽)为2.0 cm×0.4 cm,经3%柠檬酸溶液浸泡脱腥处理,调味液浸泡30 min后沥干,60℃下真空干燥至海带原料水分质量分数为20%,微波膨化功率为320 W,微波工作/间歇时间为10 s/10 s,按照这样的加工工艺可制得营养即食海带脆片产品。     

超声辅助酶解鲣加工副产物制备蛋白胨

为了提高水产加工副产物的利用率和附加值,以鲣加工副产物为原料,采用胰蛋白酶结合超声处理制备蛋白胨,并分析了鲣加工副产物超声辅助酶解过程中蛋白酶活性、水解度、氮回收率、TCA-可溶性氮回收率、酶解产物分子量分布等指标的变化,探究了超声辅助酶解的作用时间、温度以及超声功率等因素对鲣加工副产物酶解产物的影响,通过单因素实验优化确定了蛋白胨制备的最佳酶解工艺条件。结果显示,超声处理造成胰蛋白酶酶活发生显著变化,在功率为120 W的超声场下,胰蛋白酶酶活在30 min内呈上升趋势,但在超声场处理30 min后,胰蛋白酶的酶活呈明显下降趋势,至4 h后酶活变化趋势趋于平缓。超声功率和酶解温度都会影响胰蛋白酶对鲣加工副产物的酶解效率,在超声功率240 W和酶解温度50°C条件下,氮回收率比无超声处理组提高了18.66%,水解度提高了30.43%,TCA-可溶性氮回收率提高了33.20%,且超声处理有效提高了酶解液中小分子肽的含量。超声辅助酶解鲣加工副产物的最佳工艺条件为温度55°C,超声功率240 W,酶解时间4 h,此时氮回收率为81.40%,TCA-可溶性氮回收率为40.75%。     

海蜇中明矾（铝）质量分数4种测定方法的比较

铝（Al）元素在海蜇产品中以明矾的形式存在，Al在人体内累积会对健康造成危害。当前海蜇中明矾（Al）质量分数测定方法较多，各种方法的操作及检测灵敏度均存在差异。研究比较了水煮滴定法、原子吸收光谱法、比色法和酸煮滴定法4种不同方法的检测效果，对各种方法中的前处理现象差异、检测结果、检测方法的准确度和精密度及方法的可操作性等方面进行对比。结果表明，酸煮滴定法前处理只需6min，煮沸后过滤速度快，其测定结果与原子吸收光谱法的结果相近。酸煮滴定法、比色法和原子吸收光谱法回收率介于103．81％～107．60％，平均回收率为104．70％，符合分析要求。对比各种测定方法的优缺点得出，酸煮滴定法操作简便快捷、花费少，适用于生产工厂及检测机构日常检测。     

Elution and internal migration of free amino acids in fish meats by soaking in sodium chloride or sorbitol solution

ABSTRACT:   Elution and internal migration of free amino acids (FAA) in fish meats by soaking were investigated when the meat strips were soaked in various concentrations of sodium chloride (NaCl) or sorbitol solution. Rapid decrease of FAA in an earlier phase of soaking was followed by a mild one, irrespective of the kind and the concentration of soaking solution. The loss of FAA by soaking in NaCl solution was slightly larger than that in sorbitol solution. However, regardless of the kinds of soaking solution, the elution of FAA from fish meats by soaking was only dependent on the soaking time, independently of the concentration, namely osmotic pressure of the soaking solution. Conversely, sluggish migration of FAA from the inside to the surface of the meat strips proceeded by soaking. These results suggested that the elution of FAA from fish meats by soaking was driven by a simple diffusion from the surface of the meats to soaking solution, but it was regulated by sluggish migration rate of FAA in fish meats.     

利用食盐替代物柠檬酸钠制作日本方头鱼盐干品的品质

近年来,随着全球减盐行动的推进,人们对低盐饮食的健康需求日益增长,具备良好风味和外观的低钠盐食品已成为当前的研究热点之一。为适应消费者对健康饮食的需求,本研究利用柠檬酸钠作为食盐替代物制作盐干品,对其品质进行了调查研究。本研究以日本方头鱼为原料,用9%(W/V,质量浓度)食盐(对照组)和柠檬酸钠(实验组)浸渍后风干,制作了高水分半干制品,对表皮颜色和pH值,鱼肉中的Na+浓度、质地、鲜味特征物质IMP、新鲜度指标K值,以及烤制后的感官评价开展了品质研究。结果显示,实验组盐干品表皮红色色度值a*、彩度值C*和pH值显著高于对照组;其肌肉组织中Na+浓度为对照组的39%,且具有较高的持水力,较低的断裂荷重和断裂应力,断裂变形显著高于对照组;同时,IMP和K值等品质指标没有显著差异。烤制后的感官评价结果验证了以上结果,实验组的咸味评分显著低于对照组,在外观评分略高的基础上,咀嚼性、鲜味和总体可接受性等方面没有显著差异。研究表明,用柠檬酸钠代替食盐制作日本方头鱼盐干品,在保证品质的同时,可有效提升表皮色彩,降低Na+含量,是理想的钠盐替代物之一,可为水产品干制加工的工艺改善、口味调节、减少钠盐用量等提供新的思路。     

黄海南部银鲳的摄食生态

本研究应用汞质量平衡模型评估了黄海南部银鲳的日摄食量,为5.87 g wet/100 g wet/d。结合1998~2000年海上声学评估获得的资源量,计算了黄海南部银鲳年饵料消耗量为4.78×105 t,食物转换效率为1.46%。根据观察食道侧囊和分析胃含物,确认水母是银鲳的食物源之一,食道侧囊能够高效碾磨水母,是银鲳重要消化器官,胃内鳞片不是银鲳摄食对象。亟需对银鲳摄食水母的生态过程进行深入研究,从而确定银鲳控制水母暴发的潜在可能性。     

Solubility of Cod Muscle Myofibrillar Proteins at Alkaline pH

Abstract

The solubility characteristics of proteins are of interest because of their relation to many functional properties. The solubility of the proteins of washed cod muscle mince increased dramatically between pH 8.9 and 9.2 at an ionic strength of 10 mM, whereas a high but constant solubility was observed at 430 mM sodium chloride over the pH range from 7 to 9.5. At pH 9.2, the proteins of the washed cod muscle were greater than 60% soluble at a sodium chloride concentration of 6.6 mM but were salted out at slightly higher concentrations. Above about 100 mM to about 900 mM salt, the proteins were salted in, and greater than 90% solubility was achieved. Maximal extractability was observed with a ratio of 36 volumes of extracting solution to 1 weight of minced muscle at pH 9.2. At pH 8.5, the extractability of the protein increased from 11% to 24% over a range in extraction volumes of 12:1 to 144:1 of volume of extracting solution to muscle tissue weight.     

Quality preservation of salted,vacuum packaged and refrigerated mahi sefid (Rutilus frisii kutum) fillets using an onion (Allium cepa) extract

The combined effect of light salting, vacuum packaging and onion extract on the shelf life of mahi sefid (Rutilus frisii kutum) fillets under refrigeration was assessed using chemical, microbiological and sensory methods. The shelf life of control, air‐packaged, salted (APS), vacuum‐packaged, salted (VPS) and vacuum‐packaged, salted with onion extract (VPSOE) samples was determined to be up to 6, 9, 15 and 18 days respectively. The values of total volatile basic nitrogen, free fatty acid and thiobarbituric acid increased progressively during the storage period for all the treatments. However, the preservative methods applied led to an extended shelf life of fillets based on chemical indices and sensory attributes in the following order: VPSOE>VPS>APS>control group. The assay of the total viable count (TVC) revealed that 2% and 4%VPSOE produced a decrease in TVC throughout the storage period. According to the results obtained, the best method to preserve the mahi sefid fillet was by 4%VPSOE treatment.     

Lessons from Two Case Studies of Implementing Traceability in the Dried Salted Fish Industry

The traceability practices in two companies representative of those in a supply chain—one a producer of wet salted cod, the other of dried salted cod—were systematically investigated by a standard procedure. Neither company retained batch identities for all steps in the production process, and so, they did not have an effective traceability system. Although production of dried salted fish is challenging due to the many transformations taking place during production, the use of the basic technique of applying and recording unique identifiers could have provided a traceability system from delivery of wet fish through to the final dried product. This study focused on the critical points for traceability during production of both wet and dried salted fish and the practical challenges this presented.     

Estimating the economic damage caused by jellyfish to fisheries in Korea

Jellyfish cause a range of problems: they sting beach vacationers in the summer, block nuclear power plant intakes (thus disrupting the supply of electricity), decrease fishery catches, cause fishing activities to be delayed, decrease product value, and damage fishing gear. This study gauged the types and amount of damage directly caused by jellyfish. Using jellyfish monitoring data, the decreases in catch and product value for each fishery type as well as the estimated damage to each fishery type caused by jellyfish were evaluated. The results showed that the decrease in catch ranged between 6.5 and 33.7?%, and the decrease in product value ranged between 6.8 and 25.3?%, depending on fishery type. The annual direct damage caused by jellyfish was estimated to be between US$ 68.2 million and US$ 204.6 million. This corresponds to a minimum of 2.1?% and a maximum of 25?% of the annual production value, demonstrating that jellyfish cause considerable damage to the fishing industry.