响应面法优化三氯化铁回收河鲀鱼糜漂洗液中蛋白质的研究

漂洗是鱼糜加工中重要的步骤之一.鱼肉在漂洗过程中会损失大量水溶性蛋白质.对鱼糜漂洗液进行蛋白质回收,可以提高鱼糜利用率,降低污水处理成本,减少环境污染.本试验采用絮凝剂三氯化铁(FeCl3)对河鲀鱼糜漂洗液中的水溶性蛋白质进行回收,根据不同的单因素变量,研究FeCl3絮凝法回收鱼糜漂洗液中蛋白质的最佳条件.通过响应面分...     

氯化铁法回收鱼糜漂洗液中水溶性蛋白质的研究

采用氯化铁(FeCl3)作为絮凝剂进行鱼糜漂洗液中水溶性蛋白质的回收试验。分别通过体系中的pH值、回收温度和FeCl3添加量的单因素试验及该3个因素的正交试验,研究其对蛋白质回收率、透光率的影响。结果显示,FeCl3絮凝法回收鱼糜漂洗液中水溶性蛋白质的最佳条件为:pH值5.0～6.0,回收温度20～25℃,FeCl3添加量为2.0 mL;在此条件下蛋白质回收率为78.34%,透光率88.50%。表明FeCl3絮凝法是一种可用于鱼糜漂洗液中蛋白质回收利用的有效方法。     

壳聚糖絮凝法回收鱼糜漂洗水中水溶性蛋白质的工艺研究

采用壳聚糖作为絮凝剂进行鱼糜漂洗水中水溶性蛋白质的回收试验。分别通过体系的pH、回收温度和壳聚糖絮凝剂加入量的单因素试验及这3个因素的正交试验,研究其对蛋白质回收率、透光率和化学耗氧量（COD）去除率的影响,得出壳聚糖絮凝法回收40mL已知蛋白质质量浓度（9．0mg·mL-^1）的鱼糜漂洗水中水溶性蛋白质的最佳工艺条件为体系pH8．0,回收温度35℃,1％壳聚糖添加量为1．5mL。该工艺获得的蛋白质回收率为73．17％,透光率87．50％,COD去除率47．20％。     

三氯化铁在育苗水处理中的应用

我区位于胶州湾畔，育苗海水富营养化程度较高。湾内每年发生多起赤潮。育苗过程中，水质过肥以及由此产生的多种有害情况比较普遍。     

三疣梭子蟹钙调蛋白基因的克隆及在蜕皮中的功能分析

基于转录组数据库信息,采用RACE技术克隆获得三疣梭子蟹(Portunus trituberculatus)钙调蛋白基因(PTCaM)。该基因cDNA全长1981 bp,包含450 bp的开放阅读框,编码149个氨基酸,预测分子量16.8 k D,理论等电点为4.09。对序列进行生物信息学分析发现,PTCaM是一个高度保守的序列,具有EF家族典型的EF-hand钙离子结合域。同源性分析结果表明,PTCaM基因编码的氨基酸与果蝇和中华绒螯蟹(Eriocheir sinensis)的Ca M氨基酸序列覆盖率高达100%,与凡纳滨对虾(Litopenaeus vannamei)、克氏原螯虾(Procambarus clarkia)和仿刺参(Apostichopus japonicus)覆盖率高达99%。系统进化表明,PTCaM基因氨基酸序列与凡纳滨对虾、中华绒螯蟹和克氏原螯虾聚为一支。通过分析不同蜕皮时期各个组织中PTCaM的表达情况得知,该基因在蜕皮时期的各个组织中均出现差异性表达,并且差异显著,说明该基因参与蜕皮调控过程。     

虾蛄蛋白浆在三疣梭子蟹土池育苗中的应用试验

三疣梭子蟹是我国主要的海水养殖蟹类,在沿海地区的养殖已得到普及和推广,但苗种的供不应求制约着该蟹养殖业的发展。目前各地普通采用室内水泥池育苗和室外土池育苗两种育苗方式,但出苗率太低,涉及原因很多,如开口饵料、盐度、温度、培育密度等,其中饵料的数量和质量尤为熏要。采用土池育苗方法,因池塘内的天然饵料远不能满足蟹苗的摄食需要,必须补充投喂螺旋藻,蛋黄,豆浆、育苗用粉料等。因此,     

Effects of Partial and Complete Replacement of Synthetic Cryoprotectant with Carrot (Daucus carota) Concentrated Protein on Stability of Frozen Surimi

ABSTRACT

The study aimed to evaluate the effects of carrot concentrated protein (CCP) as additive on the functional and textural properties of surimi from striped catfish (Pangasianodon hypophthalmus) during six months of frozen storage (?20°C). The CCP (82.22% crude protein) was used as an additive either a lone or with a synthetic cryoprotectant (sucrose-sorbitol-sodium tri-polyphosphate). Control was made with synthetic cryoprotectant only. Molecular weight of CCP was found to be 36 kDa. After six months, the results revealed that up to 50% of synthetic cryoprotectants could be replaced by CCP during frozen storage of surimi. Biochemical parameters such as protein solubility, Ca²⁺ATPase activity, and gel strength decreased significantly (p < .05) during storage. Treatment T-3 (CCP 0.5% + 50% of synthetic cryoprotectant) maintained quality of protein significantly superior (p < .05) in respect to denaturation and other functional and sensory attributes compared to all the treatments. The microstructure images of surimi confirmed that addition of CCP modified the ice crystal growth during frozen storage. This study suggests that CCP can be a potential additive to protect protein from denaturation along with partial replacement of chemical cryoprotectants.     

Optimization of Protein Recovery During Hydrolysis of Yellowfin Tuna (Thunnus albacares) Visceral Proteins

Protein hydrolysates were prepared from yellowfin tuna viscera using Alcalase®. Response surface methodology (RSM) was applied to study the effect of independent variables, enzyme activity, temperature, and time on the protein recovery (PR) as the response. The coefficient of determination (r² = 98%) was satisfactory, and the lack of fit test showed a non-significant value for the PR model equation, indicating that the regression equation was adequate for predicting the PR under tested combinations of values. Enzyme activity at 79.9 AU/kg protein, temperature at 59.9°C, and the time of 105 min were found to be the optimum conditions to reach the highest PR (85%). Considerable soluble protein was released with increasing degree of hydrolysis (DH). The yellowfin tuna visceral hydrolysates' amino acids profiles showed high essential amino acids content, although lysine, methionine, and phenylalanine were limited. In addition, the results showed that with increasing hydrolysis time, the amino acids increased. Yellowfin tuna visceral hydrolysates were rich in flavor amino acids which can be used as a taste enhancer.     

Elucidating Comminution Steps to Enhance the Value of Surimi from Tropical Fish

Biochemical and rheological properties of surimi were examined based on: (a) salting time (from 18 to 3 min) while maintaining 21 min for total chopping time; and (b) total chopping time (from 6 to 21 min) while salting during the final 3 min. Extending salting time, which was defined as time of salt contact with proteins during chopping, significantly increased breaking force and penetration distance, while chopping time extension with fixed salting time did not. Salt soluble proteins decreased when salting time decreased; however, this trend performed contrarily against chopping time. A relationship between gel texture and salt soluble proteins was not found. Oxidation of sulfhydryl groups could occur during the chopping process when chopping without salt was extended. Surface hydrophobicity, indicating a certain degree of protein unfolding, was affected differently by chopping versus salting time. Dynamic rheology demonstrated that total chopping time affected denaturation of the myosin tail region more than salting time.     

Protein Recovery of Tilapia Frame By-Products by pH-Shift Method

The conditions of isolating protein from tilapia frame by-products (TFB) by a pH-shift process were investigated along with their physicochemical and gelling properties. The minimum solubility of TFB protein was observed at pH 5.5 and gradually increased at both acid and alkaline sides. The highest solubility was observed at pH 2 and 12. Protein solubility of TFB increased as the ratio of alkaline extraction medium and extraction time increased. The highest protein extraction was found at the ratio of ground sample to extraction medium of 1 to 9 and extraction time of 15 min. The maximum protein recovery was found at pH 12 with 19.19%. The color of all protein isolate samples obtained from either acid or alkaline extraction was dark brown. Whiteness of a TFB protein isolate extracted at pH 2 was the highest with a value of 14.69. An alkaline pH-shift process effectively removed fat as much as 95%. Breaking force and deformation of recovered protein gel from an alkaline pH-shift were higher than those from the acid counterpart.     

Application of Native Lactic Acid Bacteria (LAB) for Fermentative Recovery of Lipids and Proteins from Fish Processing Wastes: Bioactivities of Fermentation Products

Fermentation using native lactic acid bacteria (LAB) was evaluated for its effectiveness in recovering lipids and proteins simultaneously from freshwater fish visceral waste (FVW). Five different LAB isolated from fish processing waste were employed in a fermentation process that involved 10% (w/w) glucose, 2% (w/w) NaCl, and 10% (v/w) LAB. Cultures evaluated included four native isolates (Pediococcus acidilactici NCIM5368, Enterococcus faecalis NCIM5367, Pediococcus acidilactici FM37, and Pediococcus acidilactici MW2) from FVW with E. faecium NCIM5335 as the reference culture. Fermentation with native LAB resulted in recovery of > 90% oil present in the material as against no recovery in case of raw (unfermented) viscera and resulted in > 50% of degree of hydrolysis of proteins. The fatty acid profile of lipids was not affected by the fermentation process. The fermentation liquor, rich in hydrolyzed protein, exhibited antioxidant as well as antagonistic properties against several bacterial pathogens. The results clearly demonstrate the usefulness of fermentation using native isolates for simultaneous recovery of lipids and proteins from fish processing waste. It also asserts the value of fermentation as an eco-friendly method and aids in minimizing disposal/pollution problems associated with these solid wastes.     

Gel Properties of Surimi from Silver Carp (Hypophthalmichthys molitrix): Effects of Whey Protein Concentrate,CaCl2, and Setting Condition

The effects of setting time, whey protein concentrate (WPC), and calcium chloride (CaCl₂) on textural properties of silver carp surimi were investigated. Response surface methodology was used to evaluate and compare the effects of setting time (30–90 min), WPC (1–9% of protein ratio), and CaCl₂ (1–59 mmol/kg) on the gel strength. Models for breaking force, breaking distance, and gel strength of surimi gel were established. The maximum gel strength was achieved at the setting time of 60 min, WPC and CaCl₂ at 5% protein ratio, and 15–18 mmol/kg. CaCl₂ was the most significant factor affecting the gel strength.     

Recovery of Proteins from Rohu Processing Waste Using pH Shift Method: Characterization of Isolates

Yield and physicochemical characteristics of protein isolates recovered from rohu processing waste by acid- and alkali-aided protein solubilization methods were studied. pH 2.0 from acidic side and pH 13.0 from alkaline side resulted in maximum protein solubility, whereas minimum solubility was observed at pH 5.5. Except for pH 13.0, theoretical protein recovery was more than the actual recovery after centrifugation. Maximum protein recovery after the first centrifugation cycle was observed for pH 2.0 and pH 13.0, and the maximum protein recovery during the second centrifugation cycle was observed at precipitation pH 5.5 in both acidic and alkaline methods. Acidic and alkaline methods resulted in a total process recovery of 31.81% ± 0.001% and 31.11% ± 0.01%, respectively. Isolates prepared by acidic method had more whiteness and high foaming capacity, whereas isolates prepared using alkaline methods had less whiteness, tough texture, and high foaming stability. No microbial counts were detected in any of the isolates. Acid and alkaline methods described in this study can be used for the recovery of proteins from rohu processing waste with good yields and functionality.     

Antioxidant and Angiotensin-Converting Enzyme Inhibitory Activities of Protein Hydrolysates Prepared from Threadfin Bream (Nemipterus spp.) Surimi By-products

Solid wastes from threadfin bream (Nemipterus spp.) surimi production composed of head and frame were hydrolyzed by various commercial proteases (Alcalase, Flavourzyme, Neutrase, Protamex, papain, and pepsin) to produce protein hydrolysates with bioactive properties. An Alcalase-hydrolyzed sample at 24.4% degree of hydrolysis (DH) displayed the highest antioxidant activity based on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, ferric reducing antioxidant power (FRAP) assay, and potassium ferricyanide method. In addition, it showed an inhibitory activity toward angiotensin-converting enzyme (ACE) of 25.5%. Antioxidant activity of threadfin bream by-product hydrolysates increased with hydrolysis time and reached the highest DPPH activity after 6 h, while that hydrolyzed for 3 h showed the highest reducing power based on FRAP and potassium ferricyanide assays. In addition, ACE inhibitory activity was found to be at an optimum after 3 h of hydrolysis. The hydrolysates (1 mg/mL) also retarded oxidation of a linoleic acid emulsion system to a similar extent as 0.1 mg/mL 3-tert-butyl-4-hydroxy anisole (BHA), indicating a potential use in the food system. Protein hydrolysates from threadfin bream surimi by-products could be tailor-made to possess both antioxidant and ACE inhibitory activity through controlling DH of Alcalase-catalyzed reactions.     

罗非鱼碎肉酶法制备蛋白胨的工艺研究

为探讨罗非鱼碎鱼肉酶法制备蛋白胨的加工工艺,采用正交试验的方法,分别研究了木瓜蛋白酶、AS.1398中性蛋白酶、复合蛋白酶水解罗非鱼碎肉制备蛋白胨的工艺条件。结果表明:木瓜蛋白酶的最佳水解工艺条件为pH6.5,温度65℃,水解时间4h,加酶量1250 U/g,蛋白胨得率达12.63%;AS.1398中性蛋白酶最佳水解工艺条件为pH 7.5,温度55℃,水解时间4 h,加酶量750 U/g,蛋白胨得率达13.25%;复合蛋白酶的最佳水解工艺条件为pH 7.0,温度50℃,水解时间4.5 h,加酶量850 U/g,蛋白胨得率达11.43%。     

扇贝闭壳肌蛋白对鲢鱼肌肉蛋白凝胶的修饰

以栉孔扇贝闭壳肌蛋白、大豆分离蛋白、谷氨酰胺转氨酶为影响参数,鲢鱼肌肉蛋白凝胶的弹性、咀嚼性和持水性为响应参数,研究这3个因素对鲢鱼肌肉蛋白凝胶的修饰作用.通过单因素方法,分别就扇贝闭壳肌蛋白及大豆分离蛋白各自对鲢鱼肌肉蛋白凝胶的修饰作用进行了研究,结果表明,在一定范围内,添加扇贝闭壳肌蛋白和大豆分离蛋白可以改善鲢鱼肌...