Biochemical characterisation of Alaska pollock,Pacific whiting,and threadfin bream surimi as affected by comminution conditions

Salt-soluble protein, surface reactive sulfhydryl content, and surface hydrophobicity of Alaska pollock, Pacific whiting, and threadfin bream surimi were characterised, as affected by various comminution conditions. Chopping time/temperatures were explored in consideration of their habitat temperatures. Salt-soluble protein (SSP) significantly decreased when chopping time was extended. Corresponding to our follow-up study, no relationship between SSP and gel texture was found. Surface hydrophobicity was inversely proportional to SSP concentration, indicating the unfolding of protein upon comminution. Alaska pollock surimi demonstrated aggregation during chopping at 10 and 20 °C, based on the surface hydrophobicity. Surface reactive sulfhydryl (SRSH) contents of the three fish species behaved differently. The SH groups were oxidized to disulphide bonds when higher chopping temperature was applied. As a result, increased SRSH content was not observed in Alaska pollock (10 and 20 °C chopping) and threadfin bream paste (25 and 30 °C chopping).     

Effects of Thermal Sensitivity of Fish Proteins from Various Species on Rheological Properties of Gels

ABSTRACT: Thermal sensitivity of myofibrillar proteins from various fish species were compared at various preincubation (setting) treatments and chopping temperatures. There was a significant species effect on gel texture by both pre‐incubation and chopping temperatures. Whereas Alaska pollock had the highest shear stress values at 5 °C or lower temperatures, big eye, lizardfish, and threadfin bream had higher fracture shear stress values at 25 °C or higher temperatures. Decreased intensity of myosin heavy chain (MHC) for warm‐water species set at 40 °C clearly revealed higher thermal stability of these particular species.     

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.     

Elucidating Factors Affecting Floatation of Fish Ball

ABSTRACT:  Factors affecting floatation of fish ball in water were investigated. The density of threadfin bream (TB) surimi paste significantly decreased ( P < 0.05) as moisture content, temperature, or salt concentration increased. The ability of surimi paste to float or sink in water was observed according to changes in density. In gel texture measurement, when surimi was thawed for 1 h before chopping at 5 °C with 2% salt, the highest breaking force and deformation values were obtained. Apparent viscosity of surimi paste decreased as moisture content increased or salt concentration increased, and chopping temperature decreased. Setting gels in salt solution (5 or 10%) significantly reduced ( P < 0.05) stickiness, which is the tendency to stick to one another.     

Gelation of Surimi by High Hydrostatic Pressure

The effects of high hydrostatic pressure (HHP) on gel strength of Pacific whiting and Alaska pollock surimi were determined by torsion. Pacific whiting gels were made with and without 1% beef plasma protein (BPP) as protease inhibitor. HHP treated whiting (1% BPP added) and pollock gels showed greatly increased strain values at all pressure/temperature combinations compared with heat-set controls. Stress values for the same samples were variable depending on treatment and species. A three-fold increase in strain and stress was found for HHP treated whiting gels made without inhibitor.     

Comparison of the Thermostability of Red Hake and Alaska Pollock Surimi during Processing

Thermostability of red hake (Vrophycis chuss) mince and its temperature-dependent gel-forming properties were determined while using Alaska pollock (Theragra chalcogrumma) for comparison. Fish mince and surimi were subjected to various washwater, chopping and setting/ cooking temperatures, cooking times at varying salt concentrations and moisture levels. The optimal temperatures for washing and chopping were 15°C and 12°C for red hake and 10°C and 4°C for pollock, respectively. All treatments significantly affected gel properties. For red hake gels, 77% moisture, 2.0% salt, and a 40°C preheat-setting temperature produced the most cohesive gel. Gels of both red hake and pollock gradually became less cohesive with extended cooking time. The results suggest that red hake is more thermally stable than pollock.     

Linear Heating Rate Affects Gelation of Alaska Pollock and Pacific Whiting Surimi

Shear stress of Alaska pollock surimi gels with and without beef plasma protein (BPP) increased as heating rate decreased, but shear strain was unaffected. An increase in shear stress was accompanied by an increase of cross-linked myosin heavy chain. Slow heating rates increased proteolysis in Pacific whiting surimi as shown by degradation of myosin heavy chain and low shear stress and shear strain. Proteolysis of whiting surimi was lessened by BPP to a greater extent at rapid heating rates (20 and 30°C/min) than at slow heating rates (1 and 5°C/min).     

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     

EFFECT OF PACIFIC WHITING WASH WATER PROTEINS ON ALASKA POLLACK SURIMI GELS

The objective of this work was to evaluate the effect of adding insoluble proteins recovered from Pacific whiting surimi wash water (SWW) on the mechanical and functional properties of Alaska pollack surimi gels. Insoluble proteins from Pacific whiting SWW were added at 0 (control), 10, 30 or 50 g/kg into Alaska pollack grade FA surimi. Changes on mechanical properties, expressible water ( EW ) and color attributes were evaluated in pastes and gels. Results obtained showed that texture profile analysis, puncture test and EW parameters increased significantly by increasing the amount of insoluble proteins added. Although slight changes in color attributes were detected, all surimi gels remained in the same color zone. The results obtained suggest that insoluble proteins from Pacific whiting SWW could be used to improve the mechanical properties of Alaska pollack grade FA surimi gels with a minimum effect on color.

PRACTICAL APPLICATIONS

Insoluble proteins recovered from surimi wash water (SWW) of Pacific whiting added at 10–50 g/kg to Alaska pollack surimi showed no adverse effects on their textural properties (hardness, fracturability, springiness and chewiness) and slight changes on color attributes. The results obtained suggest that it is feasible the use of insoluble proteins recovered from SWW of Pacific whiting in Alaska pollack surimi. Therefore, a double target is obtained: the preservation of environment and an increase in the yield of surimi processing without negative effects on texture.     

Quantification of Alaska pollock surimi in prepared crabstick by competitive ELISA using a myosin light chain 1 specific peptide

A competitive enzyme-linked immunosorbent assay (ELISA) was developed for quantification of Alaska pollock (AP) surimi in crabsticks. Identification of fish species is complicated by processing, cooking, and additional ingredients. ELISA is a powerful tool for identification and quantification of fish species. Polyclonal antibodies were raised in rabbits against a 15-amino-acid peptide (Ala–Pro–Lys–Lys–Asp–Val–Lys–Ala–Pro–Ala–Ala–Ala–Ala–Lys–Lys) determined from the myosin light chain 1 (MLC 1) of AP. Immunoblotting showed the anti-pep-AP antibody had no significant cross-reactivity with protein additives. However, cross-reactivity of the MLC 1 from Pacific whiting, and threadfin bream surimi was observed. MLC 1 was purified from AP surimi and used as the coating protein in the competitive ELISA. MLC 1 was serially diluted and had a R² of 0.9845 following a logarithmic curve. All estimations of AP surimi were within 9% of the actual value. Inter-assay coefficients of variance ranged from 4.2% to 4.9%.     

Characterization of Thermorheological Behavior of Alaska Pollock and Pacific Whiting Surimi

ABSTRACT: Thermorheological behavior of Alaska pollock (AP) and Pacific whiting (PW) surimi was evaluated during gelation at different moisture contents (80% to 95%). The temperature sweep data (storage modulus, G', compared with temperature) for both surimi clearly indicated G' minima. Unlike for the PW surimi, the minimum values of the AP surimi was moisture-content dependent and there was a linear relationship between logarithm of concentration and reciprocal absolute temperature at gelation. The activation energy ( Ea ) for aggregation after gelation temperature at each moisture content was calculated by a nonisothermal kinetic model for both AP and PW Surimi. The Ea values increased with moisture content of the system and ranged from 172.8 to 232.9 kJ/mol. Based on the assumption that melting temperature for a thermo-reversible gel may be considered equivalent to gelation temperature for thermo-irreversible gels, an Arrhenius-type model was used to estimate the enthalpy of cross-links formation for AP surimi to be 300.3 kJ/mol.     

USE OF CYSTEINE PROTEINASE INHIBITORS FROM INJURED TOMATO LEAVES IN WHITING SURIMI

Cooking surimi paste from Pacific whiting results in a gel with poor texture due mainly to myosin degradation caused by a cysteine proteinase. Cysteine and serine proteinase inhibitors were isolated from injured and methyl jasmonate treated tomato leaves. Tomato cysteine proteinase inhibitor was stable at 60C but inactivated at 90C, making it suitable for use in surimi. Tomato proteinase inhibitors (TPI), having 7.9 papain inhibitor units, inhibited autolysis about 95% in 10 g of Pacific whiting surimi. Gel strength of Pacific whiting surimi was improved by adding only 0.0 27% of TPI to the surimi formulation. Addition of TPI did not affect the color of whiting surimi gel, while egg white needed to prevent gel weakening caused the gels to have more yellow hue (P<0.05). SDS-PAGE showed that myofibrillar protein degradation was prevented during cooking when 0.027% of TPI was included in the surimi. TPI extracted from tomato plants has potential for use as food grade additive in Pacific whiting surimi.     

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。     

TEXTURE DEGRADATION KINETICS OF GELS MADE FROM PACIFIC WHITING SURIMI

Degradation kinetics of whiting surimi gel texture were examined over a temperature/time range (40–85C, 0.5–35 min). Changes in textural properties of whiting surimi gel were mainly affected by proteolytic activity of endogenous proteinase. A decrease of failure shear stress and shear strain followed first order kinetics. The kinetic parameters developed using either isothermal or nonisothermal principles were similar. Degradation rate of gel texture increased with temperature, reaching a maximum at 55C. It then decreased to a minimum at 70C. E_a values for the activation and inactivation temperature range were 138.6–162.6 and 13.5–35.0 kJ/mol, respectively.     

Linear Programming in Blending Various Components of Surimi Seafood

Shear stress, shear strain, whiteness of surimi gels made with high and low grades of Alaska pollock and Pacific whiting were investigated to determine linearity of their relationships. A canonical form of least square linear model in mixture design showed a greater linearity (r²0.99) for blending high and low grade surimi lots. Due to linearity without interaction (p<0.001), a least cost linear program provided optimum blending for surimi lots based on value, constraints, and decision variables. Linear programming to determine optimum formulation of surimi with starches and water content was not feasible due to interactions between surimi and starch, or starch and water.     

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%.     

Effect of porcine plasma protein and setting on gel properties of surimi produced from fish caught in Thailand

Effects of porcine plasma protein (PPP) and high temperature setting on gel properties of surimi from bigeye snapper, bigeye croaker, threadfin bream and barracuda were investigated. PPP was effective in increasing breaking force and deformation of kamaboko gels set at 40°C for 30 min and heated at 90°C for 20 min. The optimum levels of PPP were 0.5, 0.5, 1.5 and 1.5 g/100 g and the optimum setting times were 2, 1.5, 1.5 and 2 h for bigeye snapper, bigeye croaker, threadfin bream and barracuda surimi, respectively. However, the addition of PPP significantly decreased whiteness (P<0.05). An increase in gel-forming ability of surimi with PPP coincided with a decrease in solubility in mixture of SDS, urea and β-mercaptoethanol, indicating the formation of nondisulfide covalent bond induced by both endogenous and plasma transglutaminase. The results supported that PPP improve the gelation of surimi in combination with setting.     

Surimi Gel Colors as Affected by Moisture Content and Physical Conditions

Colors (CIE L*, a*, and b*) of Alaska pollock (7′heragra chalcogramma) and Pacific whiting (Mecs productus) surimi gels were evaluated and related to compositional and physical conditions during preparation and measurements. Ten samples were used in each treatment. Water addition, sample size, species, cooking and test temperatures, and freeze/thaw affected lightness (L*) and yellowness (b*) values, while outside light conditions at measurement did not affect colors. Greenness (-a*) values were less affected by all conditions.     

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.     

Proteinase inhibitory activity of sarcoplasmic proteins from threadfin bream (Nemipterus spp.)

BACKGROUND: Thailand is the second largest surimi producer in the world and 50% of surimi is produced from threadfin bream. During surimi processing, sarcoplasmic proteins are removed through water washing and discarded in the waste stream. This study was aimed at investigating the proteinase inhibitory activity of sarcoplasmic proteins. RESULTS: Sarcoplasmic proteins from threadfin bream (TBSP) exhibited inhibitory activity toward trypsin but did not inhibit papain and chymotrypsin. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis under non‐reducing condition stained by trypsin inhibitory activity revealed three protein bands of molecular mass of 95, 41 and 37 kDa. Inhibitory activity of TBSP reached a maximum when subjected to 45 °C and completely disappeared at 60 °C. The breaking force and deformation of lizardfish surimi gel with added TBSP and pre‐incubated at 37° for 20 min increased with additional levels of TBSP (P < 0.05). Trichloroacetic acid–oligopeptide content of lizardfish surimi gel with added TBSP decreased with the addition of 4 g kg^?1 TBSP (P < 0.05). Retention of myosin heavy chain (MHC) increased when TBSP concentration was increased. TBSP effectively protected MHC from proteolysis at 37 °C to a similar extent as egg white powder, but efficacy of TBSP was not observed at 65 °C. CONCLUSION: TBSP could be applied to reduce proteolytic degradation of lizardfish surimi or other surimi associated with trypsin‐like proteinase, rendering an improvement in surimi gelation set at 37–40 °C. Copyright © 2009 Society of Chemical Industry