Calcium Compounds to Improve Gel Functionality of Pacific Whiting and Alaska Pollock Surimi

The effect of calcium compounds during three thermal treatments with or without setting was studied. Formation of cross-linking was investigated using SDS-PAGE. Solubility varied. Calcium acetate, chloride, and caseinate were extremely soluble. Calcium lactate had good solubility at 0.2% or higher, then in descending order were phosphate, citrate, sulfate, and carbonate. Effects of temperature on solubility were not measurable except for caseinate. When 25°C setting was applied to surimi, calcium was most effective. Effect of calcium on shear stress was dependent on species, setting temperature, and specific compound. SDS-PAGE indicated that improved gel functionality was likely due to Ca⁺⁺-dependent trans-glutaminase. Shear strain values were not affected by adding calcium compounds regardless of species or thermal treatments.     

Physicochemical Properties of Surimi Seafood as Affected by Electron Beam and Heat

Physicochemical changes of surimi seafood under electron beam (e‐beam) and heat were investigated. Heat caused color browning and texture softening. E‐beam (up to 4 kGy) deteriorated neither color nor texture when the sample temperatures were between 5 and 23°C. However, firmer texture was measured when samples were treated by e‐beam while frozen. None of the treatments changed rancidity of surimi seafood within the parameters tested. Heat, as compared with e‐beam, generated the same headspace volatiles, however, to a greater extent. E‐beam was determined to be an excellent pasteurization alternative for surimi seafood in terms of retention of fresh‐like physicochemical attributes.     

Gelation of Beef Heart Surimi as Affected by Antioxidants

Oxidation of proteins (carbonyls) and lipids (TBARS) in beef heart surimi-like materials during preparation and storage (2°C) was inhibited by propyl gallate (0.02%) or α-tocopherol (0.2%). Inhibition of oxidation did not affect surimi gel property (storage modulus, G'). Storage promoted oxidation of proteins in 0.2% ascorbate-washed mince, leading to increases in peak (～ 55°C) and final (70°C) G' of thermally induced surimi gel. Protein carbonyls in stored surimi and its sol (salted), as well as TBARS of the sol, strongly correlated with both peak and final G of gels. Incorporation of tripolyphosphate into washed mince promoted gelation whether the surimi-like material was oxidized or not.     

Physicochemical Properties of Pacific Whiting Surimi as Affected by Various Freezing and Storage Conditions

ABSTRACT: Effects of various freezing methods of surimi on the biochemical and physical properties, were examined. Stress values increased up to 3 mo and then decreased. Strain values significantly decreased over time, except freeze-dried surimi stored at -18 °C. Yellowness (b*) of the freeze-dried surimi stored at 22 °C increased significantly during storage. In addition, salt-extractable proteins (SEP) decreased while dimethylamine (DMA) increased. Freeze-dried surimi showed the highest SEP and the lowest DMA values after 9 mo storage. Electrophoretic patterns did not show any apparent damages to the MHC until 6 mo. At 6 and 9 mo, development of proteins with smaller molecular weights was observed, indicating proteolytic degradation during frozen storage.     

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).     

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.     

Microbial Inactivation and Electron Penetration in Surimi Seafood During Electron Beam Processing

Electron penetration and microbial inactivation by electron beam (e‐beam) in surimi seafood were investigated. Dose map revealed that 1‐ and 2‐sided e‐beam could efficiently penetrate 33‐ and 82‐mm thick surimi seafood, respectively. Modeling of microbial inactivation by e‐beam demonstrated that 2‐sided e‐beam may control Staphylococcus aureus if the surimi seafood package is thinner than 82 mm. The D_e‐beam value for S. aureus was 0.34 kGy. An e‐beam dose of 4 kGy resulted in a minimum of a 7‐log and most likely a 12‐log reduction of S. aureus. Microbial inactivation was slower when frozen samples were subjected to e‐beam.     

Gel Properties of Surimi from Various Fish Species as Affected by Moisture Content

Torsion, punch, and color tests as affected by moisture content were evaluated for surimi from pollock, Pacific herring, arrowtooth flounder, and Pacific whiting. Torsion stress and strain decreased linearly with increased moisture content but strain values were less sensitive to moisture than were stress values. This finding enabled mathematical normalization of torsion stress and strain values rather than adjusting the moisture content of samples prior to testing. Punch test results, while linearly related to moisture content, were not as consistent as torsion test results. The L* and whiteness increased with higher moisture content, but changes in a* and b* values were not consistent for surimi from different species.     

鲟鱼鱼糜凝胶形成过程中的物理化学变化

以鲟鱼为原料制备鲟鱼鱼糜凝胶,通过蛋白质组成、水分分布、傅里叶变换红外光谱、流变特性分析以及十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析研究了鲟鱼鱼糜凝胶形成过程中的物理化学变化。结果表明：在鲟鱼鱼糜凝胶形成过程中,其盐溶性蛋白比例和水溶性蛋白比例均下降,不溶性蛋白比例上升;肌球蛋白重链、肌动蛋白含量均下降;鱼糜蛋白质的吸收峰在1 100 cm－1附近发生红移;鲟鱼鱼糜的弛豫时间T2有4 个区间,加工后鱼糜凝胶对水分子的束缚力更大,黏弹性也更高;说明经过漂洗、擂溃和凝胶化处理后,鲟鱼鱼糜凝胶形成了致密的凝胶网状结构。本研究为进一步提高鲟鱼鱼糜凝胶的品质提供了理论依据。     

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.     

Rheological Relationships Between Surimi Sol and Gel as Affected by Ingredients

Rheological properties of surimi sol showed that consistency index (K) was surimi concentration-dependent, as it decreased with increased level of ingredients except for carrageenan which increased K value. The flow behavior index and textural properties appeared to be a function of type and level of ingredients. Unlike starch and synergistic carrageenan, egg albumin, oil and i-carrageenan did not show a composite reinforcing effect. K values measured by rotational cylindrical spindle viscometry more closely correlated with textural properties (r = 0.87 for compressive force; r = 0.87 for shear force) than did other viscometries studied.     

Rapid Heating of Alaska Pollock and Chicken Breast Myofibrillar Proteins as Affecting Gel Rheological Properties

Surimi seafoods (fish/poikilotherm protein) in the U.S.A. are typically cooked rapidly to 90+°C, while comminuted products made from land animals (meat/homeotherm protein) are purposely cooked much more slowly, and to lower endpoint temperatures (near 70 °C). We studied heating rate (0.5, 25, or 90 °C/min) and endpoint temperature (45 to 90 °C) effects on rheological properties (fracture, small strain) of washed myofibril gels derived from fish (Alaska pollock) compared with chicken breast at a common pH (6.75). This was contrasted with published data on gelation kinetics of chicken myosin over the same temperature range. Heating rate had no effect on fracture properties of fish gels but slow heating did yield somewhat stronger, but not more deformable, chicken gels. Maximum gel strength by rapid heating could be achieved within 5 min holding after less than 1 min heating time. Dynamic testing by small strain revealed poor correspondence of the present data to that published for gelling response of chicken breast myosin in the same temperature range. The common practice of reporting small‐strain rheological parameters measured at the endpoint temperature was also shown to be misleading, since upon cooling, there was much less difference in rigidity between rapidly and slowly heated gels for either species.     

白鲢鱼鱼糜凝胶过程中水分及凝胶特性的变化

本文研究了白鲢鱼鱼糜凝胶过程中的水分及凝胶特性变化规律,主要考察了鱼糜在凝胶过程中持水力、低场核磁T2横向弛豫时间及T2峰比例、凝胶特性、色差及凝胶微观结构指标的变化,并通过TG-DTGA(Thermogravimetric-Derivative Thermogravimetry Analysis)分析鱼糜凝胶在两段式加热中的结晶水含量变化。鱼糜与淀粉、水、盐混合斩拌后,采用两段式凝胶进行凝胶化。结果发现,加热过程中鱼糜持水力显著增加,在第二段加热25 min时达到最大值为96.93%;T23弛豫时间呈现下降的趋势,并在第二段加热过程中下降速度较快,在第二段加热30 min时达到最低值为30.51 ms;T23峰比例呈现上升趋势且在第一段加热过程中升速较快,在第二段加热10 min后达到最大值为93.97%;弹性、硬度等显著增加;亮度和白度呈现显著上升的趋势;结晶水含量在二段加热中呈现先增加后减少的趋势,在第一段加热30 min时达到最大值为6.59%。     

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。     

电子束辐照对梅鱼鱼糜肌原纤维蛋白结构及凝胶特性的影响

以梅鱼鱼糜为原料,研究不同电子束辐照剂量(0～9 k Gy)对鱼糜肌原纤维蛋白结构及其凝胶特性的影响,确定提高鱼糜凝胶品质的最适剂量。结果表明:低剂量(≤5 k Gy)组总巯基和活性巯基含量下降不明显,但7 k Gy和9 k Gy组下降明显;随辐照剂量的增加,Ca2+-ATPase活性明显下降,而表面疏水性先增大后减小,5 k Gy组表面疏水性值达到最大。SDS-PAGE和DSC分析显示,随辐照剂量的增加,尤其在7 k Gy和9 k Gy组,肌球蛋白重链、肌球蛋白和肌动蛋白的热稳定性下降明显;鱼糜凝胶特性结果表明,经5 k Gy电子束处理,梅鱼鱼糜的凝胶强度、白度值和持水性均高于对照及其它剂量组。综上所述,5 k Gy辐照剂量可有效改善梅鱼鱼糜的凝胶特性,且相比于高剂量(≥7 k Gy)组,低剂量辐照对梅鱼鱼糜肌原纤维蛋白结构的影响不显著。电子束辐照处理可以成为改善梅鱼鱼糜凝胶品质的一种有效手段,合适剂量为5 k Gy。     

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.     

N-Nitrosodimethylamine Formation in Cooked Frankfurters Containing Alaska Pollock (Theragra chalcogramma) Mince and Surimi

Studies were conducted to determine the feasibility of using Alaska pollock mince as a partial substitute for red meats in the formulation of frankfurters. Studies included the effects of fish form (unwashed and washed mince and surimi), percentage substitution (15 and 50) and five different methods of cooking the fish-meat franks on their N-nitrosodimethylamine (NDMA) content. The amount of formed NDMA depended on the method of cooking. Broiling and frying generated the highest levels. Microwave and boiling generated the lowest levels of NDMA, which were equivalent to the level in uncooked franks. Broiling was observed to increase the amount of dimethyl-and trimethylamine formed.     

Color and Quality of Mackerel Surimi as Affected by Alkaline Washing and Ozonation

Washing with alkaline phosphate or bicarbonate buffers (>pH 8.0) did not remove the pigments from minced mackerel. Thirty min ozonation in citrate buffer (pH 3.0) increased the whiteness (51.7 to 60.1) and L value (53.9 to 62.6), and decreased myoglobin (47.8 to 12.2 mg/100g) and total pigments (78.5 to 15.5 mg/100g). However, the deformation of surimi decreased from 0.90 cm to 0.45 cm, even though there was no change in breaking force. In comparison with untreated sample, addition of 0.10% NaHSO₃, 0.15% cysteine or 0.20% ascorbic acid during grinding resulted in substantial recovery of the deformation and breaking force of ozonated surimi.     

Functionality Changes in Oxidatively/Antioxidatively Washed Beef-Heart Surimi During Frozen Storage

Beef‐heart surimi prepared using 4 washing solutions (sodium phosphate buffer alone, buffer+NaCl, buffer+propyl gallate, and buffer+sodium tripolyphosphate) and mixed with cryoprotectants was stored at 29°C and analyzed periodically up to 12 mo. All samples showed increases in gelling capacity during storage, corresponding to oxidative changes in proteins (carbonyls, hydrophobicity). Emulsifying activity of surimi, however, did not change during storage. No major differences were found between washing conditions, but propyl gallate‐washed surimi tended to have the least oxidation and least increase in gel elasticity. Overall, frozen storage not only preserved the shelf life but also enhanced gelation of beef‐heart surimi washed with these solutions.