Gelation process in two different squid (Dosidicus gigas) surimis throughout frozen storage as affected by several cryoprotectants: Thermal, mechanical and dynamic rheological properties

Differential scanning calorimetry (DSC) was used to follow the thermal denaturation of two differently processed surimis from giant squid (Dosidicus gigas), A (isoelectric precipitation) and B (acid washing). Both surimis were added with several cryoprotectants (sucrose, sorbitol and trehalose), and kept in frozen storage at −15 °C for 6 months. DSC profiles and transition enthalpies showed that protein quality was better in B than in A surimis whether fresh or frozen. It was also demonstrated that the sucrose-plus-sorbitol mixture and trehalose were the most efficient for preserving B and A type formulations respectively after frozen storage. Mechanical (puncture), small amplitude oscillatory (SAOS) and dynamic-mechanical thermoanalyses were performed on both gels from A and B series surimis throughout frozen storage. Gels from surimi A (GA) were considerably brittler than gels from surimi B (GB) and presented significantly lower strain amplitudes. Several correlations among different experimental data have been developed.     

Rheological characteristics of suwari and kamaboko gels made of surimi from Indian major carps

The gel strength, compressibility and folding characteristic of suwari (set) and kamaboko (set and cooked) gels prepared from rohu ( Labeo rohita ), catla ( Catla catla ) and mrigal ( Cirrhinus mrigala ) surimi were examined to understand the occurrence of suwari and modori phenomena in surimi from major freshwater carps. Suwari setting of gels did not take place at lower temperatures. Suwari gels showed good gel strength at 50 °C for rohu and at 60 °C for catla and mrigal after 30 min setting time. Incubation for 60 min decreased the gel strength at 60 °C for rohu and catla. Setting at 25 °C followed by cooking at 90 °C increased the gel strength. Increased setting temperature, however, decreased the gel strength of cooked gels. Gel strength and compressibility data were supported by folding characteristics. © 2002 Society of Chemical Industry     

Influence of texture of suwari gels on kamaboko gels made from sardine (Sardina pilchardus) surimi

The textural characteristics and water holding capacity of suwari (set) and kamaboko (set and cooked) sardine surimi gels were examined in order to clarify the influence of the initial network formed in setting conditions (25, 35 and 40°C for 30 and 60 min) on the texture of the kamaboko gels. Although the texture of suwari gels set at 35°C improved with longer setting, both setting times ensured kamaboko gels with the highest gel strength. Suwari gels set at 25°C also improved with longer setting but the gel strength of both suwari and kamaboko gels was lower than at 35°C. For gels set at 40°C prolonged setting weakened the suwari networks formed, leading to kamaboko gels with poorer textural characteristics. ©1997 SCI     

Use of Konjac glucomannan as additive to reinforce the gels from low-quality squid surimi

This paper reports a study of the influence of a Konjac glucomannan aqueous dispersion (KAD) as ingredient, at different alkalinity levels, on the thermal stability of low-quality squid surimi (Dosidicus gigas) and the viscoelastic properties of its gel. An increase in elastic (G^′) and viscous (G^″) moduli at T < 50 °C, reflecting protein aggregation, and a strong decrease at T > 50 °C, reflecting structural damage, were observed in thermal gelation profiles of low-quality squid surimi. The contribution of 1% KAD (10%) to enhancement of gelation ability was assessed by evaluating the viscoelastic properties of the gels, with and without KAD, at increasing alkalinity levels. Gels with KAD at high-pH had the best rheological properties. Small amplitude oscillatory shear (SAOS) tests showed a significant decrease in rigidity, an increase in strain amplitude and a decrease in the frequency-dependence of G^′ and G^″. These results were in agreement with instrumental texture analyses, meaning that KAD may be used to overcome the negative effect of the poor protein functionality of low-quality squid surimi and achieve better gels from them.     

鱼种和亲水胶体对鱼糜制品凝胶性质的影响

考察了添加复合亲水胶体对鲢鱼、带鱼、金线鱼等鱼糜制品凝胶特性的影响。结果发现,添加亲水胶体后,带鱼鱼糜制品凝胶强度从58.38 g·cm提高至107.27 g·cm,金线鱼鱼糜制品从328.68 g·cm下降至137.55 g·cm,但鲢鱼鱼糜制品没有明显变化。另一方面,添加亲水胶体后鱼糜制品的硬度、粘结性、咀嚼性等发生下降,但水分含量、持水性、蒸煮吸水率均有显著提高。而且,添加亲水胶体后带鱼鱼糜制品中肌球蛋白重链的降解受到一定的抑制。SEM结果发现亲水胶体可以填充到带鱼和鲢鱼鱼糜制品中,但在金线鱼鱼糜凝胶结构中容易形成胶体块状,导致凝胶强度下降。      

Effect of reducing agents on physicochemical properties and gel-forming ability of surimi produced from frozen fish

Effects of different reducing agents (cysteine, ascorbic acid and sodium bisulfite) at various levels on physicochemical properties of protein, transglutaminase activity and gel properties of surimi produced from frozen croaker, lizardfish, threadfin bream and bigeye snapper were studied. Addition of cysteine resulted in the highest increase in the breaking force and the deformation of surimi gels, compared with other reducing agents. The optimum levels of cysteine were 0.05, 0.1, 0.05 and 0.1% (w/w) for surimi from frozen croaker, lizardfish, threadfin bream and bigeye snapper, respectively. Surimi from frozen croaker with cysteine added showed a similar breaking force and deformation to that produced from fresh fish. With addition of cysteine, an increase in sulfhydryl content with a concomitant decrease in disulfide bond content was generally observed. Ca²⁺ ATPase activity also increased, indicating the renaturation of the myosin molecule. T_max of peak 1 (myosin peak) of all surimi sols in the presence of cysteine was shifted to higher temperature. The increased transglutaminase activity was observed with addition of cysteine. Therefore, reducing agents, especially cysteine, recovered the denatured muscle proteins and activated the transglutaminase in the muscle, leading to the increased gel-forming ability of surimi produced from frozen fish.     

Rheological and microstructural changes in gels made from high and low quality sardine mince with added egg white during frozen storage

 This paper examines the influence of freezing temperature (–40°C or –18°C) and frozen storage temperature (–18°C or –12°C) on gels made from two different sardine minces (M1, high functional quality; M2, low functional quality), with the addition of egg white as a gel enhancing ingredient. To characterize the washed mince, proximate analyses and protein functionality were determined. Freezing at either –40°C or –18°C caused no drastic changes in gel structure. Throughout the course of frozen storage of all samples, a decrease in the water holding capacity (WHC) was detected, along with an increase in the amount of protein soluble in 8 M urea. At 90 days the gels frozen at –40°C exhibited numerous ice micro-crystals; however, they did not affect the external appearance of the gel and had hardly any effect on gel strength, shear strength, hardness, cohesiveness or elasticity. On the other hand, at 90 days the gels frozen at –18°C and stored at either temperature exhibited large, macroscopically visible ice crystals. In these samples, gel strength and shear strength increased while hardness decreased. No definite changes attributable to mince quality were detected during frozen storage. Received: 23 June 1997     

Effect of chitooligosaccharide from squid pen on gel properties of sardine surimi gel and its stability during refrigerated storage

Effect of chitooligosaccharide from squid pen prepared using lipase (COS-L) at various concentrations (0–30 g kg⁻¹) on gel properties of sardine surimi gel was investigated. Breaking force (BF) and deformation (DF) of gel were increased, when COS-L level was increased up to 10 g kg⁻¹ (P < 0.05). Water holding capacity and whiteness of gel were improved with the addition of COS-L than those of control. Gel added with 10 g kg⁻¹ COS-L had denser network with higher likeness score for all sensory attributes, compared to control. When gel incorporated with 10 g kg⁻¹ COS-L was stored at 4 °C, BF, DF and whiteness were maintained during 10 days of storage. Textural properties of surimi gel added with COS-L were higher than those of control throughout storage. Thus, incorporation of 10 g kg⁻¹ COS-L could improve gel properties of sardine surimi gel and retarded the deterioration of gel properties during refrigerated storage.     

Effects of superchilling and cryoprotectants on the quality of common carp (Cyprinus carpio) surimi: Microbial growth,oxidation, and physiochemical properties

The objective of the present study was to investigate the effect of superchilling with cryoprotectants (a mixture of sucrose and sorbitol) on microbial growth, lipid oxidation, and proteolytic degradation in common carp (Cyprinus carpio) surimi. With increasing storage time, the microbial count of surimi increased from 4.4 log₁₀ CFU/g (0 days) to 7.2, 6.2, 5.9, and 5.5 log₁₀ CFU/g (35 days; P < 0.05) in the samples superchilled at −1 °C, superchilled at −3 °C, superchilled at −3 °C with cryoprotectants, and frozen at −18 °C, respectively. The total volatile basic nitrogen and thiobarbituric acid-reactive substances exhibited an increasing trend (P < 0.05) similar to that obtained with the microbial growth, whereas the whiteness and lightness stability decreased (P < 0.05) with increasing storage time. The SDS-PAGE analysis revealed that the degree of protein degradation increased with increasing storage time. Compared with the sample frozen at −18 °C, superchilling at −1 °C and −3 °C resulted in a marked reduction in the microstructure deterioration of the myofibrillar protein gels, and the addition of cryoprotectants further reduced this deterioration. These results suggest that superchilling with cryoprotectants offers an effective approach for reducing microbial growth and lipid oxidation and limiting proteolytic degradation in common carp surimi.     

淀粉和鱼糜品质对鱼糜凝胶性质的影响

本文探讨了糯玉米淀粉、马铃薯淀粉和变性淀粉对不同品质鱼糜凝胶形成能力的影响。结果发现,添加糯玉米淀粉后鱼糜制品的破断强度从266.57 g下降至175.00 g,硬度、胶黏性、咀嚼性也发生下降,而添加马铃薯淀粉可以使鱼糜制品的破断强度和部分质构得到显著提高。另一方面,冻融变性鱼糜制备的产品其破断强度、硬度、胶黏性、咀嚼性出现下降,添加马铃薯淀粉能提高其产品的凝胶性质。不论鱼糜是否发生冻融变性,添加三种淀粉后鱼糜制品的持水力和蒸煮时的吸水率都显著提高,但鱼糜制品的色泽变差。根据SDS-PAGE结果,可以发现添加糯玉米淀粉、马铃薯淀粉和变性淀粉都不会影响鱼糜蛋白之间的交联。SEM结果表明添加马铃薯淀粉可以使鱼糜凝胶网络结构变得更加致密有序,从而增强鱼糜制品的凝胶强度。以上结果表明,马铃薯淀粉比糯玉米淀粉和变性淀粉更适合作为鱼糜制品的辅料和添加剂。      

Effects of konjac glucomannan on physicochemical properties of myofibrillar protein and surimi gels from grass carp (Ctenopharyngodon idella)

The cryoprotective effect of konjac glucomannan (KGM) on myofibrillar protein from grass carp (Ctenopharyngodon idella) during frozen storage at −18 °C and the influence of five levels of KGM (0%, 0.5%, 1%, 1.5%, and 2%) on texture properties, water-holding capacity, and whiteness of grass carp surimi gels were investigated. KGM as a novel cryoprotectant could significantly mitigate the decrease in salt extractable protein (SEP), Ca²⁺-ATPase activity, and total sulphydryl and active sulphydryl contents of myofibrillar protein during frozen storage. KGM at the level of 1% showed the same good cryoprotective effect as a conventional cryoprotectant (10% sucrose–sorbitol, 1:1, w/w). As the levels of KGM increased, breaking force and deformation of grass carp surimi gels increased significantly. Water-holding properties of the surimi gels are improved with the increasing addition of KGM, but the whiteness decreased and the colour became darker. The optimum addition level of KGM was suggested to be 1%.     

Effect of laver powder on textual,rheological properties and water distribution of squid (Dosidicus gigas) surimi gel

In order to ameliorate the gel quality of Dosidicus gigas surimi, the effects of laver powder on gel properties, rheological properties, and water-holding capacity (WHC) were investigated. Results indicated that the addition of laver powder could significantly increase the hardness, chewiness, and breaking force of surimi gels. However, the texture indexes and gel strength began to decline when additional amount exceeded 0.6%. Rheological results demonstrated that the addition of laver powder increased the storage modulus (G′) and viscosity of surimi, prolonged protein denaturation temperature in surimi gels. Moreover, the WHC of surimi gel was improved with the increase of laver powder. Further analyses in low-field nuclear magnetic resonance revealed that laver powder could shorten the transverse relaxation time, enhanced the combination with water, and altered the distribution of different water categories. The proportion of bound water and immobilized water reached its maximum and minimum at 0.6% of laver powder, respectively. Correlation analyses showed that WHC of surimi gel was negatively correlated well with the proportion of loose-bound water, but positively correlated with the strong-bound water and free water. In conclusion, the results supported that 0.6% was the optimal additional amount of laver powder for the squid-based surimi production based on the current ingredients of surimi products.     

Effects of salt-induced changes in protein network structure on the properties of surimi gels: computer simulation and digestion study

Surimi is considered a new base ingredient in special dietary foods because of its excellent gel formation properties and nutritional value. Cross-linked network structures are the basis for the formation of protein hydrogels. In this work, protein network structure induced by NaCl was investigated to evaluate its effects on texture property and digestibility of surimi gels. Micro-protein frameworks were investigated by scanning electron microscope combined with computer simulation, which indicated that the network structure became fine and smooth as a result of salt treatment. The digestibility of surimi with NaCl was higher than that of blank samples in simulated gastric juice in first 30 min, whereas the digestibility showed no significant difference (P = 0.257) in intestinal juice after 180 min. This work aids in understanding of the contribution of salt to the mechanism of surimi gels formation, and its effects on digestion, thus supporting potential applications in special dietary food.     

加工方式对鱼糜凝胶性质影响研究进展

鱼糜凝胶特性是评价鱼糜品质的关键指标。本文介绍了鱼糜凝胶形成的机理及引起凝胶劣变的内在因素,综述了新型加工方式对鱼糜凝胶性质影响的研究进展,为淡水渔深加工提供借鉴。      

膳食纤维对鱼糜凝胶工艺特性的影响

研究大豆膳食纤维(水不溶性膳食纤维)、聚葡萄糖(水溶性膳食纤维)以及两者的混合物对带鱼鱼糜凝胶工艺特性的影响.每种膳食纤维添加量均为0,10,20,30,50g/kg,分析鱼浆的质构特性、色差以及鱼糜凝胶的凝胶特性、持水性和白度等的变化情况.结果表明,大豆膳食纤维可以提高鱼糜凝胶的质构特性以及持水性但是会一定程度的降低凝胶的白度;添加5％的聚葡糖会使凝胶的质构特性和持水性显著降低但是可显著地增加鱼糜凝胶的弹性及白度;而两者混合物对鱼糜凝胶影响居于两者之间.     

The influence of superchilling and cryoprotectants on protein oxidation and structural changes in the myofibrillar proteins of common carp (Cyprinus carpio) surimi

The objective of the present study was to investigate the effects of superchilling combined with cryoprotectants (a mixture of sucrose and sorbitol, 1:1) on protein oxidation and structural changes in common carp (Cyprinus carpio) surimi. With increasing storage time, the carbonyl content of myofibrillar proteins increased from 31.4 nmol/mg of protein (0 day) to 53.4, 46.3, and 39.7 nmol/mg protein at 35 days (P < 0.05) for −1 °C superchilled, −3 °C superchilled, and −3 °C superchilled with cryoprotectants samples, respectively. The incorporation of cryoprotectants into common carp surimi was found to significantly inhibit the formation of carbonyls (P < 0.05). The protein surface hydrophobicity increased in a similar direction, and the sulfhydryl content and Ca-ATPase stability decreased (P < 0.05). Emulsifying activities, gel textural hardness, springiness, and water binding capacity were also decreased, but they exhibited significant improvements at −3 °C when combined with cryoprotectants (P < 0.05). These results suggest that superchilling treatments at −3 °C combined with cryoprotectants offer an effective approach to reducing protein oxidation in carp surimi, thereby reducing protein structural changes known to impair the texture of surimi products.     

漂洗液中氯化镁浓度对鲢鱼鱼糜凝胶特性的影响

本文为研究漂洗液中氯化镁对鲢鱼鱼糜凝胶特性的影响,通过测定凝胶强度、质构特性、持水性、蒸煮损失、白度的测定,并采用低场核磁、电泳技术和电镜扫描综合分析了其变化规律。结果表明,经含氯化镁的漂洗液漂洗鱼糜后,硬度和白度随氯化镁浓度的增加逐渐增大,其凝胶特性较用清水和0.15%Na Cl漂洗的鱼糜凝胶得到不同程度的提高。当氯化镁浓度为2.5 mmol/L时凝胶特性最佳,其中凝胶破断力、凹陷距离、凝胶强度、弹性、咀嚼度和持水性较清水和0.15%Na Cl漂洗分别提高了55.90%、42.55%、123.12%、4.59%、51.40%、20.07%和13.77%、12.64%、28.09%、1.33%、22.26%、8.19%;蒸煮损失分别降低了32.54%和22.24%;水分横向弛豫时间T₂₃分别缩短了56.18 ms和26.02 ms,且形成了致密的凝胶网络结构,说明肌球蛋白重链（MHC）发生交联,大分子聚集体形成,SDS-PAGE结果显示进入凝胶中MHC更少,条带更细窄。综合各项指标,浓度为2.5 mmol/L氯化镁漂洗液对鲢鱼鱼糜凝胶性能提升最大。      

Surface hydrophobicity and functional properties of myofibrillar proteins of mantle from frozen-stored squid (Illex argentinus) caught either jigging machine or trawling

The surface hydrophobicity and functional properties of actomyosin from the mantle of frozen squid caught either by jigging machines (AME1) or by trawl (AME2) were investigated. Two components of 155 and 55 kDa were present in the gels at zero time of storage. Degradation of the myosin heavy chain and increase in the 155 kDa component occur earlier in AME2. Irrespective of the catch method used, no significant (P>0.05) changes in protein solubility were observed. The reduced viscosity of both AME1 and AME2 decreased up to months 3 and 5 of frozen storage, respectively. At the beginning of storage, the superficial hydrophobicity of AME2 was 30% higher than that of AME1. So 1-anilino-8-naphthalene sulfonic acid of AME2 significantly increased during 3-5 months of storage period and that of AME1 at the end of storage. The emulsion activity index (EAI) of AME2 significantly (P<0.05) increased during the first month and decreased after 3 months of storage. EAI of AME1 decreased at month 3 and remained unchanged thereafter. Emulsion stability (ES) of AME2 showed a behavior that was similar to its IAE and that of AME1 remained unchanged.     

Effects of rosemary and green tea extracts on frozen surimi gels fortified with omega‐3 fatty acids

Two different sources of omega‐3 fatty acids (fish oil concentrate and menhaden oil) with or without the addition of natural antioxidants (rosemary and green tea) were incorporated into surimi gels at equivalent levels and examined for changes in sensory and physical properties and resistance to oxidation during 9 months of frozen storage. Gels with menhaden oil showed higher acceptance than gels with fish oil concentrate, which displayed a fishy taste that was partially masked by natural antioxidants. Formation of volatile compounds was similar in all samples. Upon heating to form the gel, there was a ca 20–25% decrease in the relative polyene index of the control containing no rosemary or green tea extract. Formulations with menhaden oil containing green tea and rosemary were more stable immediately after cooking; however, a slight pro‐oxidant effect occurred during storage. Omega‐3 fortified gels were whiter than gels with no added oil. Rosemary and green tea extracts increased yellowness (b*) and redness (a*), respectively. Strength increased in all formulations during frozen storage. Copyright © 2005 Society of Chemical Industry