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1.
ABSTRACT

Fish protein isolates (FPI) were produced from silver carp processing by-products by means of the isoelectric solubilization-precipitation method, and the quality was evaluated. The alkali-aided process led to significantly more lipid reduction (p < 0.05) compared with the acid-aided process. Similar protein types were extracted for the acid and alkali solubilization, and most protein types can be recovered from the raw materials, as observed in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis. The FPI was higher in total amino acids and essential amino acids (EAAs) compared with the original by-products (p < 0.05). The alkali-aided process yielded a higher nutritional and color quality than the acidic process. Furthermore, we found that alkali-aided protein had higher oxidative stability than the acid-aided protein. Our study indicates that high-quality fish proteins can be efficiently recovered from low-value silver carp processing by-products using isoelectric solubilization/precipitation, particularly the alkali-aided process, and subsequently be used in value-added human foods.  相似文献   

2.
Textural characteristics of silver carp surimi gel prepared from acid- and alkali-produced protein isolates were investigated and compared to the surimi gels derived by conventional methods. The acid-aided method showed the most efficiency to recover proteins (86.2%) in comparison to the alkaline-aided (79.8%) and conventional (76.7%) methods. In the washing of fish mince, every step resulted in reduction of sarcoplasmic protein, and consequently the myofibrillar fraction became more concentrated, as shown by the protein patterns in wash water. Some myofibrillar proteins (mainly actin and myosin) were removed along with sarcoplasmic proteins during washing, reducing yield efficiency during the conventional method of making surimi. During the pH shifting process, myosin heavy chain (MHC) was degraded during low (2.5) pH solubilization, whereas there was only a minimal loss of MHC by either hydrolysis or proteolysis during alkaline solubilization. The breaking force and breaking distance of surimi gel prepared in the pH-shifting processes were significantly (p < 0.05) greater than those of surimi gel made by conventional methods, as were expressible moisture, cohesiveness, and springiness. In conclusion, the pH-shifting technique can be considered as an efficient alternative process in recovery of greater quantities of functional protein from silver carp fillet.  相似文献   

3.
Surimi was prepared by washing with single washing cycle with cold water (T-1), alkaline saline (0.2% NaHCO3 and 0.15% NaCl; T-2) solution, and with calcium chloride and salt (0.2% CaCl2 and 0.1% NaCl; T-3), respectively, and compared with conventional washed (CW) surimi. T-2 exhibited significantly (p ≤ 0.05) increased moisture content, which correlated with increased yield, pH and also significantly decreased lipid and ash content. A significant (p ≤ 0.05) decrease in expressible moisture content was also observed in T-2, which suggested higher water holding capacity compared to other treatments. Heat-induced surimi gels exhibited highest L* (p ≤ 0.05), followed by surimi in all the treatments. In the case of L*, T-1 showed highest lightness, followed by T-2, which was comparable to CW. The lowest myoglobin content was exhibited by CW surimi (p ≤ 0.05), which is due to repeated washings. T-2 gel showed higher elasticity, texture, and overall acceptability than others (p ≤ 0.05), except for the whiteness. In all the aspects, T-2 was comparable with CW. Washing with one cycle of T-2 solution can not only improve the quality of surimi but can reduce the wastage of water that is released into the environment without further treatment.  相似文献   

4.
ABSTRACT

The effects of melanin-free ink (MFI) and pre-emulsification on gel properties and stability of bigeye snapper surimi gel fortified with seabass oil during refrigerated storage of 10 days were studied. Lipid oxidation as determined by peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) of surimi gel increased as the level of seabass oil increased (P < 0.05). When MFI was incorporated into surimi gel, lower PV was obtained throughout the storage (P < 0.05). Addition of seabass oil pre-emulsified with soy protein isolate (SPI) in the presence of MFI yielded surimi gel with the highest breaking force and could improve oxidative stability during refrigerated storage (P < 0.05). Slight decrease in whiteness was found in surimi gel added with MFI, while those added with MFI along with pre-emulsified seabass oil showed increased whiteness (P < 0.05). Addition of MFI did not affect total viable count and psychrophilic bacterial count in surimi gels. Thus, the incorporation of pre-emulsified seabass oil prepared using SPI in conjunction with MFI could improve quality and oxidative stability of gel from bigeye snapper surimi.  相似文献   

5.
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.  相似文献   

6.
Protein isolates from hydrolyzed and unhydrolyzed shrimp waste were prepared using the pH shift method. The conditions for protein isolation from unhydrolyzed shrimp waste by the pH shift method were standardized with respect to waste to distilled water ratio (1:2.5, 1:5, 1:7.5, and 1:10 w/v) and the alkaline pH (9.0, 10.0, and 11.0) to which the waste was to be adjusted before protein precipitation for higher yield of protein isolate. The yield of precipitate with waste to distilled water ratio of 1:2.5 (17.3 ± 0.9) was lower (p < 0.05) compared to the other three dilutions. The pH to which the waste is adjusted before precipitating the proteins at pH 4.5 had no effect (p > 0.05) on the yield. The antioxidant activity of the protein isolate obtained by the pH shift method from unhydrolyzed waste was compared with that obtained from the waste hydrolyzed with Alcalase®. The DPPH scavenging activity of protein isolate after enzyme hydrolysis was significantly higher than that of protein isolate from unhydrolyzed waste. With respect to recovery of total antioxidant activity, protein isolation from unhydrolyzed waste was superior to hydrolyzed waste due to higher yield.  相似文献   

7.
A 120-day evaluation was performed to determine the impacts of various carbon source supplements on the water grade and production of bottom- and filter-feeding carp inside a minimum-water-exchange system. The outcomes revealed that the overall ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, total inorganic nitrogen, and orthophosphate concentrations in every one of the carbon source treatments were significantly less (P?<?0.05) than the control. The net production of silver carp and bighead carp in the molasses treatment was significantly higher (P?<?0.05) than that in the control. The total feed conversion rates of the fish in the molasses and the mixed carbon source treatments were significantly lower (P?<?0.05) than in the control, while the total protein efficiency ratio values in the corn starch, molasses, and mixed carbon source treatments were significantly higher (P?<?0.05) than those in the control. The bioflocs significantly (P?<?0.05) impacted the muscle makeup of crude protein, crude fat, and ash of mirror carp. The current examination showed that the increased generation and feed used in mirror, silver, and bighead carp may be reached with an enhanced water grade when different carbon sources were added, while the use of molasses, an organic carbon source, was optimal compared to the other carbon sources due to its low price and good effect.  相似文献   

8.
Changes in the muscle protein during processing of half-dried salt-cured silver carp (Hypophthalmichthys molitrix) was studied. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) assay indicated that hydrolysis of the muscle proteins took place during processing, particularly at the drying stage. Further in vitro assay on the activities of Cathepsins B and L, which are related to the degradation of the myofibrillar proteins, indicated that Cathepsins B and L still had high activity at the last stage. Total soluble nitrogen (TSN) and nonprotein nitrogen (NPN) showed significant decrease (p < 0.05) and then increased during the drying stage (p < 0.05), which may be caused by the degradation of the myofibrillar proteins and other insoluble proteins. Furthermore, the retained enzymatic activity of Cathepsins B and L may contribute to the proteolysis. Our research indicates that heat pump drying is a novel drying method that can produce the traditional flavor of dried aquatic products, and the formation of high-quality flavor may be due to the degradation of the myofibrillar proteins and water-soluble proteins.  相似文献   

9.
朱亚军  叶韬  王云  林琳  陆剑锋 《水产学报》2021,45(7):1140-1150
圆苞车前子壳粉(psyllium husk powder, PHP)是一种富含膳食纤维的食品亲水胶体。为了解其在鱼糜制品中的作用,本实验以冷冻鲢鱼糜为研究对象,以凝胶强度和持水性(water holding capacity, WHC)为考察指标,研究了PHP的添加量、凝胶化温度和凝胶化时间3个因素对鱼糜凝胶特性的影响。在单因素试验的基础上,进行了三因素三水平的正交试验和验证试验。正交试验结果得到最佳工艺条件:PHP添加量0.1%,凝胶化温度45°C,凝胶化时间2 h。单因素试验结果表明,添加适量PHP (0.1%～0.3%)能够增加鱼糜凝胶的硬度和WHC,但对破断距离有不利影响;根据验证试验中蒸煮损失率、SDS-聚丙烯酰胺凝胶电泳(SDS-polyacrylamide gel electrophoresis, SDS-PAGE)和扫描电镜(scanning electron microscopy, SEM)分析,PHP的添加降低了较高凝胶化温度时凝胶的蒸煮损失,PHP或许可以促进肌球蛋白重链(myosin heavy chain, MHC)分子间交联,减缓蛋白质降解,形成更加致密的凝胶结构。本研究对PHP作为一种新型食品原料应用于开发优质健康鱼糜制品进行了初步的探究,以期为丰富亲水胶在影响鱼糜凝胶特性中的应用研究提供一定的参考。  相似文献   

10.
池塘和稻田养殖模式对金边鲤和建鲤肌肉品质的影响   总被引：3，自引：0，他引：3  
分析了稻田和池塘养殖模式下金边鲤和建鲤肌肉营养成分、理化特性和质构特性,并进行营养价值评价,评估金边鲤的肌肉品质,为开发和推广金边鲤稻田养殖提供数据依据。结果显示,稻田金边鲤的粗脂肪、粗灰分和系水力均显著高于池塘金边鲤;稻田建鲤和池塘建鲤的基本营养成分除水分外差异均不显著;稻田金边鲤肌肉的硬度、弹性、咀嚼性显著高于池塘建鲤和稻田建鲤,硬度和恢复性显著高于池塘金边鲤,而内聚性显著低于池塘金边鲤、池塘建鲤和稻田建鲤;测定的17种氨基酸中,4组鱼肉的Lys含量均高于WHO/FAO标准和鸡蛋蛋白标准,稻田金边鲤的∑TAA、∑EAA、∑DAA和∑NEAA均高于池塘建鲤和稻田建鲤,且EAA/TAA比值更接近FAO/WHO要求的40%的标准;稻田和池塘金边鲤的EAAI均超过100分,高于稻田和池塘建鲤(82.31～83.36分);测定出的24种脂肪酸中,稻田金边鲤的∑SFA、∑MUFA和DHA+LA+油酸总量均高于其他3组。研究表明,金边鲤和建鲤鱼肉可作为人体优质的赖氨酸源,稻田金边鲤肌肉比建鲤和池塘金边鲤肌肉更富有嚼劲,其肌肉必需氨基酸、不饱和脂肪酸及高度不饱和脂肪酸含量更高,且组成比例更符合人体需求。稻田养殖金边鲤的肌肉品质优势明显,具有较高的产业开发潜力。  相似文献   

11.
The present study investigated physicochemical and protein structural changes in common carp muscle subjected to different freeze–thaw (FT) cycles. With increasing number of FT cycles, the thawing losses, cooking loss, L*- and b*-value increased, and shear forces and a*-value decreased (p < 0.05). The study showed that multiple FT processes were detrimental to color and water-holding capacity of carp muscle. The increases in thiobarbituric acid reactive substances and carbonyl content with concomitant decrease in sulfhydryl group content (p < 0.05) showed that multiple FT caused carp lipid and protein oxidation, especially for the carp muscle subjected to five freeze–thaw cycles. Myofibrillar protein isolated from FT muscle showed an increased hydrophobicity, reduced ATPase activity, and enhanced susceptibility to thermal aggregation (p < 0.05). These protein structural changes resulted in major losses in muscle quality. Overall, the disrupted protein structure, together with the denaturation of myofibrillar protein induced by FT, was most likely associated with lowered muscle quality.  相似文献   

12.
加工鱼产品种类的电泳鉴定   总被引：1，自引：0，他引：1  
介绍了几种鱼的白肌在乳酸脱氢酶和蛋白电泳表型上种的特异特征。链,镛,草,青,尼罗罗非鱼白肌乳酸脱氢酶的谱带数不同,活性强度亦不同;蛋白质电泳图谱的迁移率也有差异。这类特征可为加工产品的种类鉴定提供可靠判据。鱼类电泳鉴定技术的标准化及其应用将为规范鱼品加工业,检验鱼产品提供理想的检测手段。  相似文献   

13.
Gel properties of blends of surimi from silver carp and white croaker set for a range of times and at different temperatures were evaluated for breaking force, breaking distance, and whiteness. Total protein content was 12% in all samples, and the concentration of white croaker surimi protein in the blends was designed at 0, 10, 20, 30, and 40%. The blended surimi had greater gel strength than either of the two types of surimi alone. Breaking force and breaking distance after setting were also significantly higher than that of the blended surimi cooked directly without setting. The blended surimi exhibited less modori than either of the two types of surimi alone heated to 50°C. The whiteness values of the blended surimi were significantly higher than that of white croaker alone. These results indicate there are advantages to be gained in utilizing surimi from freshwater silver carp in blends with surimi from marine captured white croaker which is becoming limited in supply.  相似文献   

14.
ABSTRACT

The autolytic profile of oxeye scad mince was characterized. Mince showed higher proteolytic activity than washed mince. The highest autolysis was observed at 65 and 60°C for mince and washed mince, respectively. Both mince and washed mince showed the optimum pH for autolysis at pH 9.0, and their activities decreased with increasing NaCl concentration (0–3.5%). Autolysis of washed mince was markedly inhibited by soybean trypsin inhibitor (SBTI), suggesting that myofibril-associated proteinase was serine proteinase. Sarcoplasmic proteinase was characterized to be heat-activated alkaline proteinase having the optimal pH and temperature of 9.0 and 60°C, respectively. The activities were stable at pH range of 8.0–11.0 at 20–40°C. The crude proteinase was inhibited by N-p-tosyl-L-lysine chloromethyl ketone, SBTI, and phenylmethanesulfonyl fluoride, suggesting the predominance of serine proteinases, especially trypsin. NaCl suppressed the activity while β-mercaptoethanol, dithiothreitol, and CaCl2 activated the activity. Therefore, trypsin-like proteinase is a major endogenous proteinase responsible for autolysis in oxeye scad muscle. The present results can be used as scientific guidelines to predict the gel strength of surimi made from oxeye scad muscle.  相似文献   

15.
The physicochemical and gel properties of myofibrillar protein (MFP) from sin croaker fish were studied during ice storage for 18 days. Significant changes in the trends of solubility, Ca2+ ATPase enzyme activity, surface hydrophobicity, and water holding capacity of extracted MFP were observed by the 6th day of storage. The Ca2+ ATPase enzyme activity reduced significantly (p < 0.05) by the 6th day of storage. However, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) did not show a remarkable change in the concentration of myosin heavy chain. Surface hydrophobicity increased almost four times from its original value of 18.98 µg; whereas, water holding capacity showed a fluctuating trend during storage. The emulsion capacity of the MFP was in the range of 0.89- to 1.92-mL oil/mg protein during storage. The gel strength value (313.45 g.cm) of heat-induced gel prepared from fresh minced meat decreased significantly (p < 0.05) by the 6th day of ice storage. Texture profile analysis revealed that changes in hardness and gumminess were concurrent to steeply reducing breaking force up to the 6th day. The histological observation showed gradually increasing gaps between muscle fibers. The histological observations and physicochemical quality indicated that the sin croaker fish can be used for producing good quality surimi when stored for up to 6 days in ice.  相似文献   

16.
Textural property of surimi products is a prime factor in determining the acceptability of consumer as well as market value. Gelatin is one of the most popular biopolymers widely used in food industry as gelling agent with the unique textural properties. Therefore, the addition of gelatin along with the use of protein cross-linkers could be a means to modify the texture of surimi gel, which can fit the demand of consumers. Surimi from the threadfin bream (Nemipterus bleekeri) was added with bovine gelatin (BG) and bovine/fish gelatin mix (BFGM; 1:1, 2:1, 1:2, 4:1, and 1:4) at 10% protein substitution in combination with and without microbial transglutaminase (MTGase) at 1.2 units/g surimi. Textural properties, whiteness, expressible moisture content, protein pattern, and microstructure and sensory properties of gels were determined. When MTGase at 1.2 units/g surimi was incorporated, the increases in breaking force and deformation were noticeable in both surimi gels, with and without 10% BG added ( p < 0.05). On the other hand, surimi gels added with BFGM at all bovine/fish gelatin ratios had the higher breaking force and deformation, compared with that added with BG, when MTGase was incorporated. Addition of BG or BFGM lowered the expressible moisture content and whiteness of surimi gel ( p < 0.05). Based on SDS-PAGE, band intensity of myosin heavy chain and actin of surimi gel decreased when surimi gel was added with all gelatins, regardless of MTGase addition. The microstructure study revealed that surimi gel network became finer and denser with the addition of MTGase (1.2 units/g surimi), but the coarser and irregular structure was obtained when gelatin was incorporated. Gelatin, especially bovine/fish gelatin mix, at an appropriate level could be used as the protein additive in surumi gel in conjunction with MTGase in order to improve the textural and nutritive properties of the products.  相似文献   

17.
This study was conducted to investigate graded levels of dietary zinc on the growth, flesh quality, and the relationship between flesh quality and muscle antioxidant status in young grass carp (Ctenopharyngodon idella Val.). Per cent weight gain (PWG), special growth rate (SGR), feed intake (FI), feed conversion ratio (FCR), anti‐hydroxy radical (AHR), superoxide dismutase (SOD), catalase (CAT), glutathione reducase (GR) activities and glutathione (GSH) content were significantly increased with increasing levels of Zn up to a point, and thereafter declined (P < 0.05). Serum zinc, alkaline phosphatase (AKP), muscle anti‐superoxide anion (ASA), glutathione peroxidase (GPx), glutathione‐S‐transferase (GST) activities and collagen content were significantly enhanced with dietary zinc levels up to a point (P < 0.05), beyond which it plateaued. Cooking loss, shear force and malondialdehyde (MDA) were significantly reduced with increasing level of zinc up to a point, and thereafter increased (P < 0.05). The pH value significantly increased with the increasing zinc levels, whereas the trend of protein carbonyl content was opposite. Flesh quality was positively related to the antioxidant enzymes activities in muscle of young grass carp. These results indicated that optimum zinc could improve growth, and improve flesh quality partly through improving muscle antioxidant status of young grass carp.  相似文献   

18.
The aim of this study was to investigate effects of dietary geniposide (GP) on growth performance, flesh quality, and lipid metabolism of grass carp, Ctenopharyngodon idella (95.2 ± 0.6 g), fed seven different diets, including a control diet; Eucommia ulmoides (EU)–supplemented diet (20 g/kg); and GP‐supplemented diets containing 100, 200, 400, 600, and 800 mg/kg GP, respectively. Weight gain rate was significantly improved (P < 0.05) and feed conversation ratio was significantly decreased (P < 0.05) by supplementation of EU. Grass carp fed 100–800 mg/kg GP‐supplemented diets showed significantly higher total collagen and alkaline‐insoluble collagen content in muscle than control (P < 0.05). Contents of total collagen and the alkaline‐insoluble collagen content in the skin of grass carp were significantly increased by dietary 600–800 mg/kg GP and EU (P < 0.05). Fish fed diets containing 600–800 mg/kg GP showed significantly lower muscle crude lipid content than the EU, control, and 100–400 mg/kg GP groups (P < 0.05). Fish fed 400–800 mg/kg GP diets had significantly higher muscle fiber density and lower muscle fiber diameter and serum triglyceride level than the control (P < 0.05). In conclusion, supplementation of GP could improve flesh quality, but not growth of grass carp. The supplemental level of GP for improving flesh quality was estimated to be a 400–600 mg/kg diet.  相似文献   

19.
The aim of this investigation was to evaluate the effect of wheat, citrus, and carrot fiber on protein oxidation and denaturation of crab leg analog pastes and gels produced from Alaska pollock surimi. There were no significant differences between protein carbonyl contents of the crab leg analog pastes with and without dietary fibers (DF; p > 0.05). The extractability of salt soluble protein in crab leg analog pastes significantly decreased by the addition of DF (p < 0.05), whereas it did not change in the crab leg analog gels (p > 0.05). The electrophoretic patterns in the pastes and gels showed that the addition of carrot fiber followed by wheat fiber and citrus fiber protected the degradation of myosin heavy chains in paste.  相似文献   

20.
Bay essential oil (BEO) at 0.5 and 1 g/100 g was added to surimi gels fortified with omega (ω)-3 rich oils. Although the fortification resulted in increased (P < 0.05) susceptibility of surimi to lipid oxidation, 0.5 g/100 g BEO significantly reduced TBARS (P < 0.05). Addition of ω-3 rich oil or BEO improved the texture. Color values of the surimi seafood were improved particularly when BEO was added. Sensory properties, water activity, and pH values were generally within the acceptable range. These results suggest that the incorporation of BEO may allow food manufacturers to nutritionally enhance surimi seafood with beneficial ω-3 rich oils.  相似文献   

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