Alaska Pollock (Theragra chalcogramma) Mince and Surimi as Partial Meat Substitutes in Frankfurters: N-Nitrosodimethylamine Formation

Studies were conducted to determine the feasibility of using 3 forms of Alaska pollock (AP) as a partial substitute for meat in a nitrite-cured product. The effect of several pre- and post-processing storage conditions on N-nitrosodimethylamine (NDMA) were studied in frankfurters substituted with 15 and 50% unwashed and washed mince and surimi. In franks made with unwashed mince, frozen stored prior to processing, NDMA increased during frozen storage; little change was observed in franks containing washed mince and surimi. Refrigerated storage of franks generally showed a decrease in NDMA with all 3 forms of fish. Overall, the use of washed mince and surimi at the 15% substitution level gave mean values less than 2 ppb NDMA, even after boiling. The results indicate that 50% unwashed AP mince should not be used as a partial substitute for meat in frankfurters.     

近红外光谱技术快速无损测定狭鳕鱼糜水分和蛋白质含量

通过拟合狭鳕鱼糜的近红外漫反射光谱与其水分和蛋白质含量,建立近红外定量模型,用于狭鳕鱼糜水分和蛋白质的快速无损检测。模型采用偏最小二乘法(PLS)拟合,水分和蛋白质的定标模型相关系数分别达0.98 和0.96以上,优于近红外透射光谱建立模型的预测结果。模型的相对标准偏差(RSD)＜ 10%,相对分析误差(RPD)＞ 3,表明该模型能准确快速地测定狭鳕鱼糜中的水分和蛋白质含量,且可用于实际生产中。     

Effect of soy protein isolate on gel properties of Alaska pollock and common carp surimi at different setting conditions

The effects of soy protein isolate (SPI) on the gel properties of different grade Alaska pollock and common carp surimi at different setting conditions were evaluated and compared. Breaking force and distance of gels decreased with increasing SPI concentrations in direct cook (85 °C for 30 min) and in cook after setting at 30 °C for 60 min conditions. The effect of SPI on gel strength of common carp surimi was less than in Alaska pollock surimi. The breaking force obtained for addition of 10% SPI to Alaska pollock surimi was higher than for surimi alone when cooked after incubation at 50 °C for 60 min. Addition of SPI decreased the whiteness and increased the yellowness of the gel. The gel structure showed that the addition of SPI modified the microstructure of the fish protein gel, thus resulting in surimi with different gelling properties. Copyright © 2004 Society of Chemical Industry     

Yam affects the antioxidative and gel‐forming properties of surimi gels

The antioxidative activities and textural properties of pollock surimi gels containing four different yams were determined to evaluate the potential of using yam as a health ingredient and an alternative source for starch in surimi‐based seafoods. Surimi gels containing 20% fresh yam showed higher α,α‐diphenyl‐β‐pricryl‐hydrazyl (DPPH) radicals scavenging activities and total phenolic contents than the gels without yam. Two tested cultivars, 70W34 and 70W35, did not show significant reductions in antioxidative activities when used in surimi gel while three other cultivars revealed species‐dependant declines in both the DPPH scavenging activities and total phenolic contents. The surimi gel containing the cultivar 70R20 showed the highest breaking forces and deformations. In general, 20% fresh yam could be used to form a yam‐containing surimi gel having similar textural properties with a potato starch containing pollock surimi gel. The dried yam powders might be used at the amount of 30% fresh yam equivalent without causing significant losses of the textural properties of pollock surimi gels. Copyright © 2005 Society of Chemical Industry     

EFFECTS OF CHITOSAN ON GELLING PROPERTIES OF LOW QUALITY SURIMI

In order to produce a strong and elastic gel from low quality walleye pollock surimi, use of chitosan was examined. The strength of gels was nearly doubled by the addition of 1.5% chitosan when salted surimi pastes were set below 25C. In contrast, chitin did not cause any changes in the physical texture of gels. When salted surimi pastes containing 1.5% chitosan were set at 20C, a large decrease in the proportion of myosin heavy chain was observed with a concomitant increase in components with molecular weights heavier than myosin heavy chain. Since the addition of EGTA, an inhibitor of transglutaminase, to surimi reduced gel strength and minimized myosin heavy chain polymerization, it is suggested that the enhancing effect ofchitosan on the gel formation of walleye pollock surimi could be due to the activity of the endogenous transglutaminase known to be present in this surimi.     

TEMPERATURE-TOLERANT FISH PROTEIN GELS USING KONJAC FLOUR

Shear stress and strain values of surimi gels made from Alaska pollock and Pacific whiting were measured upon cooling, reheating, and freeze/thawing. Konjac flour was introduced to investigate its ability to maintain fracture properties of surimi gels against various temperatures. Gel colors (CIE L*,a*,b*) were also measured as affected by various levels of konjac flour. Konjac flour (5%) showed its ability to reinforce shear stress of gels 8-10 times in both whiting and pollock surimi. Gels with 4% konjac flour were the most heat-tolerant in both surimi. Surimi gels with konjac flour exhibited an ability to maintain consistent shear strain values against repeated freeze/thaw abuse. Konjac flour, up to 2%, increased lightness of gels, while yellow hue increased gradually up to 5%.     

N-Nitrosothiazolidine and its 4-Carboxylic Acid in Frankfurters Containing Alaska Pollock

In marine fish of the gadoid family trimethylamine oxide can decompose to formaldehyde. It can then react with cysteine and cysteamine, that may in turn react with nitrite, if present, to form N-nitrosothia-zolidine-4-carboxylic acid (NTHZC) and N-nitrosothiazolidine (NTHZ). The NTHZC and NTHZ content of Alaska pollock surimi-meat frankfurters were similar to or lower than those found in an all-meat control, even at 50% substitution. No correlation was found between age of the fish protein prior to processing into surimi meat frankfurters and any measured variables.     

Thermal Conductivity of Surimi–Measurement and Modeling

To measure temperature-dependent thermal conductivity of surimi, a line-source probe system was developed. Effects of test conditions and sample history were investigated. Thermal conductivity of Alaska pollock surimi having 0, 4, 6, 8, and 12% cryoprotectant levels was measured in the range -40 to 30°C. Thermal conductivity of surimi has a relatively weak dependence upon cryoprotectant level when water content of the sample is controlled at 80.3%. From measured data, the Schwartzberg model and its modification were selected for future prediction. Three parameters in the model, T_i, B, and K′_f had a linear variation with cryoprotectant concentration.     

DIFFERENT ARRANGEMENT OF ɛ-(γ-GLUTAMYL)LYSINE CROSS-LINKING IN ALASKA POLLOCK (THERAGRA CHALCOGRAMMA) SURIMI PROTEINS BY STREPTOVERTICILLIUM AND ENDOGENOUS TRANSGLUTAMINASES DURING SUWARI PROCESS

The objective of the present study is to compare the protein cross‐linking reaction in Alaska pollock surimi that is catalyzed by a commercially available microbial transglutaminase and by endogenous Alaska pollock transglutaminase. The endogenous transglutaminase was inhibited by EGTA and activated by CaCl₂ The microbial transglutaminase was added to the salted surimi with and without EGTA and CaCl₂. These surimi pastes were incubated at 25C up to 24 h followed by cooking at 90C. The resultant gels were fractionated into soluble and insoluble (aggregate) fractions by SDS‐urea extraction. Compositional analysis revealed that the aggregate consisted predominantly of cross‐linked myosin heavy chain. The distribution of ?‐(γ‐glutamyl)lysine isopeptide in the soluble and aggregate fractions andpeptide mapping analyses of the aggregate fraction demonstrate that the formation of isopeptide cross‐links in Alaska pollock surimi proteins during suwari process differs when catalyzed by the microbial transglutaminase and endogenous transglutaminase.     

Effects of adding fish gelatin on Alaska pollock surimi gels

Fish gelatin is a food additive obtained after hydrolysis of collagen from fish skin. The importance of fish gelatin as a food additive is increasing due to its increased commercial availability. Surimi is washed minced fish meat used as the raw material for seafood analogs like crabmeat substitutes. The most important attributes of surimi are gelling and whiteness. The objective of this work was to determine the effect of using fish gelatin as an additive in surimi to improve the mechanical and functional properties of gels. Surimi gels were prepared by mixing grade A or FA surimi (Alaska pollock) with salt (20 g/kg w/w) and commercial fish gelatin at 0 (control), 5, 7.5, 10, or 15 g/kg (w/w) previously dissolved in water (200 mL/kg surimi). The solubilized paste was incubated at 40 °C for 30 min followed by cooking at 90 °C for 15 min. Changes in mechanical properties (torsion test), a functional property (expressible water content) and color attributes of surimi gels were measured. Grade FA surimi gels containing 7.5–15 g/kg of fish gelatin showed an improved expressible moisture. However, gelatin added at 15 g/kg showed a disruptive effect detrimental to the mechanical properties. Color parameters were modified slightly. Whiteness attribute as affected by increasing the fish gelatin was instrumentally detected but not observed by sensory panelists. Gelatin did not change the overall color attributes and all gels remained in the grayish region. These results indicated that fish gelatin did not have an advantage for using as a functional additive in Alaska pollock surimi grades A or FA. However, it can be used at up to 10 g/kg without a negative effect on the mechanical properties.     

复合南极磷虾糜中鱼糜配比量及外源添加剂对其凝胶特性的影响

采用等电点沉淀法制备了南极磷虾糜,对其营养成分进行了分析,并与阿拉斯加狭鳕鱼糜复配提高凝胶性能。通过分析复配虾糜的凝胶强度、持水力、感官评分结果,结合差示扫描量热值的变化及动态流变学特征,来确定最佳的鱼糜复配比例,并在此基础上探究不同功能性外源添加剂及其添加量对复合鱼糜凝胶强度的影响。结果表明,制备的南极磷虾糜中,粗蛋白含量为81.01%,氟含量为79.79 mg/kg,必需氨基酸含量达521.5 mg/g蛋白;确定的虾糜与鱼糜的最佳配比为3:7,此复配比例条件下,相较于南极磷虾糜,复合鱼糜凝胶的热相变温度(45.73、108.26 ℃)与南极磷虾糜(19.24、97.56 ℃)相比,显著提升(p<0.05),储能模量(G')上升幅度增加,表明凝胶强度得到了明显提升;功能性辅料中,大豆蛋白、蛋清粉、木薯淀粉和TG酶的添加量分别为15%、15%、20%、0.4%时,复合虾糜的凝胶强度值达到最大,表明复配以鱼糜后,可加入添加剂进一步改善南极磷虾糜的质构特性。     

Effect of rainbow trout (Oncorhynchus mykiss) plasma protein on the gelation of Alaska pollock (Theragra chalcogramma) Surimi

ABSTRACT:  The effect of rainbow trout plasma protein (RPP) on the gelation of Alaska pollock surimi was determined to evaluate the possibility of its commercialization as a new protein additive. For modori gel, the breaking force, deformation, whiteness, and water holding capacity increased as the addition amount of RPP (0 to 0.75 mg/g) increased, and decreased at higher concentration of RPP (0.75 to 1.50 mg/g) ( P < 0.05). Protein solubility of modori gel in the mixture of SDS, urea, and β-mercaptoethanol decreased as the addition amount of RPP increased up to 0.75 mg/g, and increased at higher concentration of RPP (0.75 to 1.50 mg/g) ( P < 0.05). The contents of trichloroacetic acid-soluble peptide decreased as the addition amount of RPP (0 to 1.50 mg/g) increased ( P < 0.05). Based on the result of sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis (PAGE), most myosin heavy chain of surimi was not degraded when RPP was added. Thus, RPP was supposed to act as a protease inhibitor in the gelation of Alaska pollock surimi. An RPP of 0.75 mg/g was the optimal concentration to prevent the gel weakening of Alaska pollock surimi. Compounds with molecular weights less than 10 kDa in RPP had no significant effect on the gelation of Alaska pollock surimi based on the result of the dialyzed RPP.     

Application of recombinant chum salmon cystatin to Alaska pollock (Theragra chalcogramma) surimi to prevent gel weakening

ABSTRACT:  Recombinant chum salmon cystatin (RC) expressed in Saccharomyces cerevisiae was purified by His-select nickel affinity chromatography. The specific inhibitory activities of RC against papain and cathepsin L were 7.45 and 10.24 U/mg, respectively. RC was stable over pH 5.0 to 7.0 and at temperature below 65 °C. RC was used to prevent the gel weakening of Alaska pollock surimi. RC at 100 μg/g showed the highest inhibitory activity against the autolysis of surimi based on the analysis of TCA-soluble peptides. As the concentration of RC increased, both the breaking force and deformation of modori gel greatly increased ( P < 0.05). The addition of RC resulted in less expressible drip, which coincided with the increase of whiteness. More myosin heavy chain (MHC) was retained as the addition of RC increased. Therefore, RC could prevent the degradation of proteins in Alaska pollock surimi and was better than egg white (EW). Thus, RC could be applied to Alaska pollock surimi to prevent gel weakening and RC at 100 μg/g was the optimal concentration.     

Effect of Freezing and Frozen Storage of Alaska Pollock on the Chemical and Gel-Forming Properties of Surimi

Alaska pollock was headed, gutted, and frozen at sea in pre- and postrigor condition. Surimi made from this fish held at - 29°C showed a gradual loss in gel-forming ability with time of storage. This loss in gel-forming ability was accompanied by a loss in viscosity and Ca⁺⁺-ATPase activity of the surimi over the 9-month storage period. The gel strength of kamaboko gels showed an inverse linear relationship with gel moisture over a limited moisture range. Simply freezing and thawing pollock resulted in surimi with significantly lower gel strength than that from fresh pollock.     

Quantification of Shrimp in Shrimp-Surimi Mixtures using Urea Gel Isoelectric Focusing

A method of quantitate the percent content by weight of shrimp in surimi-pink shrimp mixtures was developed by comparing peak areas of two Alaska pollock surimi-specific (pI 7.11 and 7.17) and two shrimp-specific (pI 5.46 and 5.52) protein bands on isoelectric focusing (IEF) gels. An equation describing the linear relationship between peak areas and protein from the standard samples of surimi, shrimp and surimi-pink shrimp mixtures was also developed. Using this method, unknown mixtures containing 10.0, 12.4 and 5.7% pink shrimp, respectively, were determined in blind studies to contain 8.3, 12.0 and 4.4% shrimp and 85.7, 86.8, and 92.7% surimi, respectively.     

Optimum chopping conditions for Alaska pollock, Pacific whiting, and threadfin bream surimi paste and gel based on rheological and Raman spectroscopic analysis

Rheological and Raman spectroscopic properties of surimi from three species [Alaska pollock (AP) (cold water), Pacific whiting (temperate water), and threadfin bream (warm water)] were investigated as affected by various chopping conditions. Comminuting Alaska pollock surimi at 0 °C demonstrated superior gel hardness and cohesiveness when chopping time was extended to 15-18 min; however, long chopping time at higher temperatures resulted in a significantly decreased gel texture particularly at 20 °C. Warm water fish threadfin bream exhibited higher gel texture when chopping was done longer at higher temperature. Rheological properties were significantly affected by both chopping time and temperature. Species effect, based on their thermal stability, was readily apparent. Raman spectroscopy revealed a significant change in disulfide linkage and the reduction of secondary structure upon extended chopping. Dynamic oscillation rheology demonstrated the damage of light meromyoisn and lowering of onset of gelling temperature as the chopping time was extended. PRACTICAL APPLICATION: Chopping conditions to determine gel quality and manufacture surimi seafood are varied by all manufacturers. This paper covering three primary species for surimi with their suggested optimum chopping conditions: 15 min for Alaska pollock when chopped at 0 °C, 15 min for Pacific whiting at 15-20 °C, and 18 min for threadfin bream at 25-30 °C. The use of optimum chopping condition should maximize the value of each surimi and provide consistent quality to the end users.     

Effect of Various Types of Egg White on Characteristics and Gelation of Fish Myofibrillar Proteins

ABSTRACT:  Three types of egg white protein (regular dried egg white [REW], special dried egg white [SEW], and liquid egg white [LEW]) were compared for their effect in surimi (CON), containing no egg white (EW). They were characterized for enzyme inhibition and time of EW addition, either with cryoprotectants prior to freezing or during gel preparation, using Pacific whiting surimi. In addition, the setting (suwari) effect and fish protein–EW protein interactions (dynamic rheological properties, total sulfhydryl groups, and fracture gel analysis) were evaluated using Alaska pollock surimi. After 12 mo frozen storage, adding 2% and 3% SEW to Pacific whiting surimi during chopping significantly ( P  < 0.05) increased the force and deformation values compared to adding the respective EW before freezing. The highest ( P  < 0.05) force (175.2 g) and deformation (9.0 mm) values after 12 mo were obtained when 3% SEW was added during chopping. Enzyme autolysis showed that addition of 2% EW protein was effective at inhibiting enzyme activity. During setting, adding 2% SEW maintained force (1047.4 g) and deformation (17.9 mm) values similar ( P  > 0.05) to CON (1055.1 g; 19.3 mm) and significantly ( P  < 0.05) better than 2% REW (666.1 g; 15.6 mm). Texture results corresponded well to other data where 2% SEW showed the lowest total sulfhydryl groups (48.3 mole/10⁵ g), and higher elastic modulus (G'), which suggests improved protein interaction for gel formation. Overall, the addition of 2% to 3% SEW improved gel textural properties of Pacific whiting and Alaska pollock fish protein.     

Sodium Asocorbate Affects Surimi Gel-forming Properties

Effect of sodium-L-ascorbate (SA) on the gel-forming properties of Alaska pollock surimi was studied with respect to optimum level, surimi quality, gel setting, vacuum chopping, freeze-thaw and thermal stabilities, and salt and moisture levels. SA significantly improved gel cohesiveness and sensory firmness of fiberized products with maximum strengthening effect at a 0.2% level. Its effectiveness was directly related to surimi quality regardless of vacuum treatment indicating the unimportance of airborne oxygen. Freeze-syneresis promoted by ascorbatc during frozen storage was moderated by the use of hydrox-ypropylatcd-modified starch.     

冻藏条件对带鱼鱼肉及其鱼糜凝胶特性的影响

为研究不同冻藏条件对带鱼鱼肉及其鱼糜凝胶特性影响,将新鲜带鱼分别置于-7、-13、-18和-23℃下冻藏15～120 d,期间测定带鱼鱼肉理化特性(羰基、巯基、Ca²⁺-ATPase活性、TBARS),随后将鱼肉制成鱼糜凝胶后测定凝胶特性(色泽、凝胶强度、持水力),并结合扫描电镜观察微观结构。结果表明,随着冻藏时间的延长,鱼肉羰基含量和TBARS值逐渐升高,巯基含量和Ca²⁺-ATPase活性下降。冻藏温度越低,鱼肉的各项指标变化程度越小。除-7℃冻藏60 d后的样品TBARS值大于0.58 mg MDA/kg外,其余样品均未发生腐败。随冻藏时间的延长,带鱼鱼糜凝胶色泽逐渐劣变,持水力逐渐降低,冻藏温度越低色泽和持水力的变化越小。带鱼鱼肉在四个温度下冻藏120 d制成的鱼糜凝胶,其凝胶强度分别下降了72.33%、54.13%、39.17%和29.31%。通过SEM观察发现更低的冻藏温度能够使鱼糜凝胶保持良好的三维网状结构,抑制带鱼凝胶的劣变。综上,随冻藏时间的延长,带鱼鱼肉及其鱼糜凝胶特性逐渐劣变,随着冻藏温度由-7℃降低到-23℃,劣变过程...     

Physicochemical Changes in Alaska Pollock Surimi and Surimi Gel as Affected by Electron Beam

ABSTRACT: Alaska pollock surimi and surimi gels (cooked) were subjected to various doses of electron beam (e-beam). Shear stress of surimi gels increased as the dose increased up to 6 to 8 kGy and then decreased. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed gradual degradation of myosin heavy chain as the dose increased. The degradation was slower for frozen samples. The integrity of actin was slightly affected by high doses (25 kGy). The amount of sulfhydryl groups and the level of surface hydrophobicity of Alaska pollock surimi decreased as the dose increased, suggesting formation of disulfide bonds and hydrophobic interactions. The sulfhydryl groups and hydrophobicity of surimi gels increased as the dose increased up to 6 kGy and then decreased.