Fish Gels Research Articles

Rheological Characteristics and Microstructure of Common Carp (Cyprinus carpio) Surimi and Kamaboko Gel

Common carp is cheap and prolific in Australian waters and is regarded as an aquatic environmental pest. In order to add value to this fish species, surimi and kamaboko was prepared from common carp and its rheological and microstructure characteristics were compared with those produced from Alaska pollock and threadfin bream. Temperature sweep tests were run under 100-Pa stress and 0.1-Hz frequency, obtained from linear viscoelastic ranges of all tested fish gels. Storage modulus (G′) thermographs of all samples consisted of two positive peaks and a plateau zone in between. The sol-gel transition was completed at about 53 and 61 °C for these Alaska pollock and threadfin bream gels, respectively, whereas it was recorded at about 69 °C for common carp gel. At these temperatures, G′ of Alaska pollock gel was recorded at 330 kPa, which was 71% and 88% greater than that from threadfin bream and common carp gels, respectively. Furthermore, Alaska pollock and threadfin bream gels had greater gel strength than the gel prepared from common carp surimi. Textural quality could be associated with cross-linking in the gel network. From scanning electron microscopy studies, the microstructure of Alaska pollock gel matrix had about 15,450 polygonal structures per square millimeter with an average area of about 9 µm2. For threadfin bream and common carp gels, the polygonal structures were larger and 12% and 39% fewer, respectively, than those of Alaska pollock gel. However, these results cannot be only attributed to the species variation among tested fish as some other factors such as harvest location, physiological state, handling and processing method, etc. were not considered in this study.

EFFECT OF SETTING CONDITIONS USING MICROBIAL TRANSGLUTAMINASE DURING OBTENTION OF BEEF GELS

ABSTRACT Microbial transglutaminase (MTG) is a food additive widely used to improve the mechanical properties of beef, poultry and fish gels. The aim of this study was to determine the effect of incubation temperature on the mechanical properties of restructured beef gels treated with MTG. The restructured beef gels were obtained by adding 0.0% (untreated) or 0.3% MTG. Three incubation temperatures (40, 50 or 60C) for 30 min were used, followed by cooking at 90C for 15 min. Control samples without incubation were also prepared. Changes in the mechanical properties (texture profile analysis and puncture test), color attributes, expressible water and cooking loss were determined. Results indicated that the maximum mechanical properties can be obtained by incubating beef pastes at 50C for 30 min with minimal effect on color, expressible water and cooking loss when 0.3% of MTG is added. PRACTICAL APPLICATIONSMeat and poultry are considered nonsetting proteins, and consequently, an incubating treatment to allow optimal cross‐linking has not been considered, and the products are usually obtained by direct cooking. Our results showed that beef gels containing 0.3% of microbial transglutaminase incubated at 50C showed higher mechanical properties than control gels without incubation. These results could be useful to improve the mechanical properties of beef gels.

Influence of alginate and microbial transglutaminase as binding ingredients on restructured fish muscle processed at low temperature

AbstractBACKGROUND: In view of the increasing demand for fresh products in Western countries recently, there is considerable interest in commercialising restructured fish products having the appearance of fresh fish. A number of methods have been studied for the purpose of inducing cold gelification. Two of the most common methods, namely addition of alginates and addition of transglutaminases, have been studied mainly in connection with meat products. The present study deals with the use of alginate and transglutaminase as additives in cold gelification of minced hake (Merluccius capensis) muscle. The experiments were targeted on the effects of concentration and combined effects of additional additives on physicochemical characteristics and mechanical properties.RESULTS: As regards mechanical properties, the effectiveness of sodium alginate was improved by addition of a low concentration (1 g kg−1) of calcium chloride (CaCl2), whereas a higher concentration (10 g kg−1) reduced the binding ability of the alginate. The presence of sodium caseinate (15 g kg−1) in combination with microbial transglutaminase (MTGase) was important in helping to increase the work of penetration in fish gels induced at low temperature. Examination of the chemical properties of the muscle gels showed that sodium alginate did not establish covalent protein–protein bonds, while MTGase dramatically increased the number of covalent bonds formed between adjacent muscle proteins.CONCLUSION: With both ingredients, thermostable fish gels of good quality were produced at temperatures below 10 °C. Gels induced by sodium alginate were considerably improved by addition of 1 g kg−1 CaCl2. However, gels induced by MTGase were better suited for the preparation of restructured products. Copyright © 2008 Society of Chemical Industry

The Effect of Washing, Microbial Transglutaminase, Salts and Starch Addition on the Functional Properties of Sardine (Sardina Pilchardus) Kamaboko Gels

The functional properties of kamaboko gels, produced from sardine surimi (SS), were evaluated based on three factors: (a) washing conditions, (b) absence or presence of microbial transglutaminase (MTGase), and (c) addition of CaCl2, MgCl 2, and NH4Cl. Fish gels prepared from sardine mince washed at pH 5.5 showed the highest L* values and whiteness index (WI). A similar trend was also observed for firmness. Addition of MTGase had a beneficial effect on the L* values and WI as well as on firmness and cohesiveness of kamaboko gels ( p<0.05). Fish gels containing CaCl2 or MgCl 2 were lighter and firmer compared to those containing NH4Cl ( p<0.05). Three transitions, using a differential scanning calorimeter (DSC), were observed during heating of surimi containing 50g/kg of unmodified wheat starch (UWS), occurring at 45.2 °C, 63.3 °C, and 71.4 °C and were substantially the same when UWS was added at higher concentrations ( p≥0.05). The thermal gelation of SS, studied with Dynamic Mechanical Analysis (DMA), occurred at three or four distinct stages named: gel softening, low temperature gelation, gel resolution, and high temperature gelation. The cooling process was found to be crucial in surimi gelation since it strongly contributed in the development of gel rigidity.

EFFECTS OF AMIDATED LOW METHOXYL PECTIN ON HEALTHY RESTRUCTURED FISH FOOD FROM MEXICAN FLOUNDER (CYCLOPSETTA CHITTENDENI)

ABSTRACT Nowadays an increasing demand of functional foods exists. In the case of fish products, pectins can be added to offer an additional healthy value to the consumer with a positive effect in the textural properties. Therefore, it is possible to take advantage of species with low commercial value or that are captured incidentally and sacrificed by error, like Mexican flounder (Cyclopsetta chittendeni). The objective of this work was to determine the effect of the addition of amidated low methoxyl pectins (ALMPs) on the functional and mechanical properties of restructured fish products from Mexican flounder. Different concentration of pectins (0 as control, 10, 20, 30 or 50 g/kg) and degrees of amidation (5, 10 or 25%) were studied. The fish pastes obtained were incubated at 40C for 30 min before they were cooked at 90C for 20 min. Backward extrusion, expressible water (Ew) and color of fish pastes were determined, and treated gels were characterized by changes in mechanical properties (texture profile analysis, puncture test and torsion test), Ew and color. Results obtained suggest that the ALMP with the highest degree of amidation increased mechanical properties and the water‐holding capacity of fish gels. Gels containing 10 g/kg of 10 or 25% ALMP showed adequate mechanical and functional properties with almost no changes perceptible in color attributes. ALMP can be used to offer to consumers healthier fish foods based on mexican flounder.PRACTICAL APPLICATIONSA new application to Mexican flounder (Cyclopsetta chittendeni), an abundant fish species in the Gulf of Mexico, was found. High volumes of this species are incidentally caught as part of the shrimp bycatch and discarded because of their small size. The results showed that with the use of amidated low methoxyl pectin as additive, a healthier fish food can be obtained.

Studies on Fish and Pork Paste Gelation by Dynamic Rheology and Circular Dichroism

The muscle paste of fish, pork, and their mixtures were prepared to study the gelling characteristics by dynamic rheological measurement. The gelation mechanisms of muscle paste were also investigated by circular dichroism. Gel formation of fish paste occurred in 2 steps of 5 to 35 and 51 to 90 degrees C respectively, while pork paste mainly in 1 step of 49 to 72 degrees C. Gel formation was relative to the alpha-helix unfolding of myosin, which responded the melting temperatures of 40 and 50 degrees C for fish myosin and 50 and 60 degrees C for pork myosin, respectively. Alpha-helix unfolding of myosin was beneficial for gel formation. During gel formation, G' of muscle paste was linearly related to alpha-helical content of myosin. The interactions of fish and pork proteins at high temperature (>35 degrees C) could change the gel forming characteristics of muscle paste. Mixed paste exhibited a similar gelation pattern to individual fish paste with 2 visible increases in G'. Addition of pork could suppress the breakdown of fish gel structure at approximately 50 degrees C. Mixing pork and silver carp in a certain ratio could improve the gel properties of silver carp products.

Changes in textural and rheological properties of gels from tilapia muscle proteins induced by high pressure and setting

Tilapia meat pastes were prepared with a combination of hydrostatic pressure (200 MPa) and setting (50 °C) treatments, to investigate the changes in their rheological properties, gel-forming ability, whiteness and protein solubility of their gels. The control, a cooked gel (90 °C/30 min), was elastic and white, with low gel-forming ability. Gels formed by setting were elastic, rigid and mainly consisted of covalent bonds. Gels formed by pressurisation were soft and consisted of hydrogen bonds and hydrophobic interactions. Pressurisation prior to setting reinforced the gel structures, by formation of both covalent and non-covalent bonds. Setting prior to pressurisation did not alter the characteristics of the gel. Setting under pressurisation constructed a viscous gel with non-covalent bonds. Various fish gel products were formed in this study.

Fiber-rich functional fish food from striped mullet ( Mugil cephalus) using amidated low methoxyl pectin

The intake of pectin has been reported as healthful for people with risk of cardiovascular diseases. Moreover this is a known fiber able to reduce plasmatic cholesterol. But this hydrocolloid is low compatible with gels from muscle proteins. Only amidated low methoxyl pectins (ALMP) have been reported as adequate to increase mechanical properties of restructured fish products. Striped mullet ( Mugil cephalus) is an abundant subutilized fish in the Gulf of Mexico. The objective of this work was to determine the effect of the degree of amidation of ALMP in the functional and mechanical properties of restructured fish products from striped mullet. Different concentration of pectin (0 as control, 10, 20, 30 or 50 g/kg) and three degree of amidation (5%, 10% or 25%) were studied. Fish pastes were incubated at 40 °C for 30 min before cooking at 90 °C for 20 min. Backward extrusion, expressible water and color of fish paste were analyzed and treated gels were characterized by changes in mechanical properties (texture profile analysis, puncture test and torsion test), expressible water and color. Results obtained suggest that ALMP with higher level of amidation increased mechanical properties and the water holding capacity of fish gels. Gels containing up to 50 g/kg of 25% ALMP showed adequate mechanical and functional properties with almost no changes perceptible in color attributes. ALMP can be used to offer to consumers healthier fish foods, which have high content in proteins, polyunsaturated fatty acids and pectin and low content in cholesterol.

Beneficial Effects of Ascorbic Acid on Heat-Induced Fish Gel (Kamaboko) from the Superoxide Anion Radical

We examined the participation of the superoxide anion radical (O(2)(-)) in the beneficial effects of L-ascorbic acid on heat-induced fish gel (Kamaboko). The generation of a thiyl radical (S.) in glutathione, ovalbumin, and actomyosin was examined by electron spin resonance spectroscopy coupled with spin trapping. O(2)(-) was provided by the photoactivation of riboflavin. The typical line shape for S. was observed with the glutathione and ovalbumin samples. A signal different from that for S. was detected with the actomyosin sample, and its intensity markedly decreased when the SH groups of actomyosin had been modified. The signal was eliminated when superoxide dismutase was added, but unaffected when catalase or an equivalent amount of heat-inactivated superoxide dismutase or catalase were added. These results suggest that S. in actomyosin was produced by the reaction with O(2)(-) and that the beneficial effects of L-ascorbic acid are due to a different mechanism in Kamaboko from that in bread.

An approach to feeding high-percentage fish diets to mice for human and wildlife toxicology studies

Experimental feeding of sport fish to rodents has been an important tool for the study of biological effects induced by a contaminated fish diet. Most rodent feeding studies have used low-to-moderate levels of tissue from large fish species incorporated into diets fed to rats and have given little consideration to issues of diet palatability or nutrition. There are currently no rodent diet models suitable for assessing the risk to human populations of diets very high in daily fish content or to wildlife species consuming high percentages of whole, small-bodied fish. In this study, we describe an approach to feeding mice high percentages (up to 50%) of homogenized, whole fish using Atlantic herring ( Clupea harengus) as a test species. We created a novel gel diet medium for mice that contains a variety of nutritional supplements and is flexible in terms of the fish percentage that can be incorporated. In choice trials, mice preferred 30 and 35% fish gels to their regular commercial dry chow, indicating that the gel diet medium was palatable. In a longer feeding trial, mice ate 35% fish gel for 12 days and 50% fish gel for 12 days (total of 24 consecutive days) and did not differ in body mass compared to age- and sex-matched controls. We conclude that our fish-based gel diet is suitable for rodent feeding trials in toxicology studies that examine dose responses to fish consumption and risk in human and wildlife populations among which daily fish intake is very high. Our general approach may also be applicable for feeding mice materials other than fish.

EFFECTS OF SAMPLE THICKNESS ON BITE FORCE FOR RAW CARROTS AND FISH GELS

ABSTRACT The effects of food thickness on human bite force were investigated using a multiple‐point sheet sensor and electromyography. The total force and contact area were directly measured in real time using the sensor, and the average stress detected between the teeth and a food sample (active stress) was derived from the ratio of the force to the contact area. Raw carrots and fish gels with different thicknesses were bitten between the upper and lower incisors or molars by healthy women. For hard and brittle carrots, the peak force, contact area and active stress at the fracture point were greater in thicker samples when biting with incisors. For soft and tough gels, the peak force and contact area were increased as thickness increased; however, the active stress was similar in incisor bites. These values did not differ significantly with thickness in the molar bites of both samples. Although the force and contact area were greater for molar bites than incisor ones, the active stresses at fracture point were independent of tooth position. The sample thicknesses influenced the bite force of humans and the stress applied to the sample, and the effects differed with sample texture.

Quercetin properties as a functional ingredient in omega‐3 enriched fish gels fed to rats

AbstractWistar rats were fed with surimi gels containing either sunflower oil, fish oil (ω3), and the same formulation additionally supplemented with 1.05 g kg−1 quercetin (ω3‐Q). Antioxidant capacity was highest in gels with added quercetin when measured by the ferric‐reducing/antioxidant power (FRAP) method, but not by the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) free radical assay. Lipid stability was not enhanced by quercetin since commercial fish oil already contains stabilizers. Quercetin modified neither rheological properties nor water‐holding capacity of the gels; however, it produced a large increase in yellowness (b*). Serum lipid profile of rats was not significantly different. Total serum antioxidant capacity by FRAP was significantly increased only in the ω3‐Q group. Plasma malondialdehyde was similar in the ω3 and ω3‐Q groups, indicating no prooxidative effect of quercetin in vivo. These results suggest that quercetin might be used as a food ingredient in fish gel to improve some nutritional properties of the gel. Copyright © 2005 Society of Chemical Industry

Restructured products from arrowtooth flounder (Atheresthes stomias) using high-pressure treatments

The texture of arrowtooth flounder, an underutilized fish species abundant in Alaska, degrades during cooking, a phenomenon that has been associated with proteolysis. Interest in safer fish products by high-pressure processing (HPP) is increasing. The objective of this study was to evaluate the effect of HPP treatments at 400 and 600 MPa for 1 and 5 min on the mechanical and functional properties of heat-induced fish gels obtained from arrowtooth flounder fish paste. Three thermal treatments of pressure-treated and control samples were evaluated: 90 °C for 15 min (kamaboko); 40 °C for 30 min plus 90 °C for 15 min (setting); 60 °C for 30 min plus 90 °C for 15 min (modori). Changes in texture profile analysis parameters, water holding capacity, sodium dodecyl sulfate polyacrylamide gel electrophoretic pattern and color parameters were determined. HPP improved the mechanical properties of heat-induced gels. Proteolysis of fish gels when they were incubated at 60 °C was not inhibited by HPP. The results obtained suggest distinct mechanisms of protein aggregation for pressure- and heat-induced fish gels.

Effect of high‐pressure treatments on mechanical and functional properties of restructured products from arrowtooth flounder (Atheresthes stomias)

AbstractRestructured fish products from arrowtooth flounder (Atheresthes stomias), an abundant and subutilized species from the Gulf of Alaska, were obtained by hydrostatic pressure processing (HPP) at 400 and 600 MPa with 0–5 min pressure‐holding time. Minced fish meat was massaged with 20 g kg−1 salt at 10 °C during 5 min, stuffed in commercial sausage case and HPP‐treated. Raw and cooked (90 °C for 15 min) pressure‐treated gels were characterized by changes in mechanical properties (texture profile analysis and punch test), protein solubility, electrophoretic profile, expressible water and color. The mechanical properties of raw fish gels increased with pressure level and pressure‐holding time while solubility decreased. Myosin aggregation shown by SDS‐PAGE was associated with changes in mechanical and functional properties. The values for mechanical properties of heat‐induced gels were higher in cooked pressure‐treated samples than in the heat‐only control. Copyright © 2004 Society of Chemical Industry

Application in Restructured Fish Products of Transglutaminase Obtained by Strepto verticillum ladakanaum in Media Made from Hydrolysates of Sorghum Straw

ABSTRACT: The efficiency of microbial transglutaminase (MTG), obtained by Streptoverticillum ladakanaum in the fermentation of sorghum straw hydrolysates to increase mechanical properties of restructured fish products, was evaluated. Fish gels were obtained from Mexican flounder (Cyclopsetta chittendenni) by (1) adding MTG obtained in the fermentation of sorghum straw hydrolysates (SMTG) at 0.3 units/g; (2) adding commercial MTG (CMTG) at 0.3 units/g; (3) adding 0.4% calcium chloride to activate the endogenous TG; and (4) without additives as control sample. SMTG more efficiently increased the mechanical properties of restructured products and induced a low value of expressible water, similar to the control (6% to 7%). Results demonstrated the feasibility of producing an efficient MTG from agricultural wastes. Keywords: fish, transglutaminase, microbial, restructured, sorghum

Preparation of surimi gels from striped mullet ( Mugil cephalus) using an optimal level of calcium chloride

Optimal conditions for the setting phenomenon in surimi, prepared from striped mullet ( Mugil cephalus) by adding calcium chloride, were determined. Concentrations of calcium chloride (0–0.4%), temperature (25–45 °C), and time (30–90 min) were optimised to improve the shear stress and shear strain properties of fish gels. After incubating under selected conditions for setting, all gels were cooked at 90 °C for 15 min. Shear stress was mainly affected by the calcium concentration, while shear strain was moderately affected. Maximum shear stress (89.6 kPa) was obtained by employing a concentration of calcium of 0.4%, a temperature of 39.3 °C and a time of 1 h. Under these conditions, a shear strain of 1.47 was obtained. The results suggest that the mechanical properties of surimi gels can be improved, simply, by adjusting the level of calcium to induce activity of the endogenous transglutaminase.

Negative effect of combining microbial transglutaminase with low methoxyl pectins on the mechanical properties and colour attributes of fish gels

The objective of this work was to determine the effect of combining different concentrations of microbial transglutaminase (MTGase) and types of low methoxyl (LM) pectin on the mechanical properties (textural profile analysis, puncture test) and the colour attributes of fish restructured products. A disruptive effect was observed when LM pectin and MTGase were added to fish gels. Adding 1% MTGase with LM32 pectin significantly decreased the hardness (3.85 kg), springiness (0.631) and chewiness (0.434 kg). When LM32 pectin and 0.1% MTGase were added together, significant decreases of the three puncture test parameters were observed. The chroma of fish gels decreased significantly when 0.3% MTGase was added. Fish gels containing the LM35 pectin had higher chroma values than all other fish gels with the same level of MTGase. Hue value was increased in all fish gels after increasing the MTGase level. The results obtained showed that LM pectin is not suitable for use in products containing MTGase.

Use of amidated low methoxyl pectin to produce fish restructured products

Recently, amidated low methoxyl (ALM) pectin has been shown to improve functional and textural properties of surimi. The objective of this work was to determine the effect of ALM pectin on fish pastes and functionality of restructured fish products. Whole muscle of sole ( Cyclopsetta chittendenii) was used to obtain solubilized pastes with 2.5% salt and 0 (control), 1, 2, 3 or 5% ALM pectin. Changes in firmness, consistency, expressible water contents and colour parameters ( L ∗, a ∗, b ∗, chroma and hue) were measured in pastes. Fish gels were obtained by incubating pastes at 40 °C for 30 min, followed by 90 °C for 15 min. Changes on breaking force, deformation and gel strength of restructured products were measured. ALM pectin decreased significantly ( P<0.05) firmness and consistency of pastes when added at 1%. Increases in both parameters were observed using higher ALM pectin levels. Adding ALM pectin to the paste increased the yellowness and redness ( P<0.05) according with a ∗ and b ∗ values. ALM pectin improved significantly ( P<0.05) breaking force and gel strength, and decreased the content of expressible water when added at 1 or 2%. Higher level of addition decreased significantly all mechanical properties. Results obtained indicated that ALM pectin at 1% could be employed to improve water holding capacity and mechanical properties of restructured fish products.

Effects of hydrocolloids and high-pressure-heating processing on minced fish gels

Multivariate statistical methods were applied to data sets of measured gelling properties of blue whiting mince with several hydrocolloids added (locust bean gum, guar gum, xanthan gum, carboxymethylcellulose, ι-carrageenan, κ-carrageenan or alginate) induced under different pressure-time-temperature gelling conditions. The main differences between gels were attributed to the process; all the gels were classified in three clusters on the basis of gelling treatment: (1) high-pressure at moderate heating, (2) high-pressure at cold temperature and (3) heating at atmospheric pressure. Cluster 1 was characterized by very elastic, light gels with high water holding capacity. In cluster 2, gels presented high puncture test properties (breaking deformation, breaking force, work of penetration) and high cohesiveness and water holding capacity. Cluster 3 gels presented low penetration test properties and cohesiveness; high adhesiveness and hardness; high lightness and yellowness. Each cluster was subdivided to describe the gel properties between the hydrocolloid groups, attributing the differences mainly to yellowness (b*), breaking deformation, breaking force and work of penetration.

Surimi‐Derived Elver Substitutes: Microscopic Appearance and Physicochemical and Sensory Properties

ABSTRACT: Elver substitutes made from kamaboko‐type fish gels have recently been introduced onto the market in Spain. Kamaboko is made by addition of 2.5 to 3.0% salt, and optionally other additives, to surimi (minced fish). The present study investigated the usefulness of microscopy techniques for characterizing the structure and composition of two elver substitutes of this type. Sensory and physicochemical analyses were also performed, with the aim of defining the organoleptic characteristics of these products. The results obtained indicate that microscopy techniques are useful for rapid identification of certain additives in products of this type. Furthermore, many of the between‐brand differences in microscopic appearance showed clear correspondence with differences in physicochemical and sensory properties.