Rheological and Structural Properties of Wiener-Type Products Substituted with Vital Wheat Gluten

Mechanical properties of wiener batters substituted with vital wheat gluten (VWG) or acid-solubilized (deamidated) VWG were studied. Substitution led to decreased storage (G') and loss (G”) moduli. Cooking profiles showed initial modulus decreases due to fat melting, with G’ reaching minimum around 50-55°C, followed by rapid increases. Sharp G” and tan 5 transitions appeared near 48°C. Substitution caused upward shift in transition temperatures, and at 20%, decreased moduli. Substitution caused no significant (p < 0.05) decreases in cook yield or texture. Microscopical examination revealed random binding of gluten to meat protein, forming continuous networks. Batters containing deamidated gluten had structure similar to all-meat or VWG-substituted batters.     

Effect of Gradual Heating and Fat/Oil Type on Fat Stability,Texture, Color,and Microstructure of Meat Batters

The effects of endpoint cooking temperature (40, 50, 60, 70, 80, and 90 °C) on emulsion stability, texture, color, and microstructure of meat batters prepared with different fats/oils were studied. Canola oil treatments showed the highest cooking loss whereas hydrogenated palm oil provided the most stable meat batters. Rendered beef fat was less stable than regular beef fat. Increasing endpoint cooking temperatures resulted in a progressive reduction of water holding capacity in all treatments. As temperature was raised, meat batters showed higher hardness and cohesiveness values, but no appreciable changes in cohesiveness above 60 °C. Canola and hydrogenated palm oil treatments showed the highest hardness and chewiness values. Lightness (L^*) values of all meat batters increased significantly with increasing temperature from 40 to 60 or 70 °C; no major changes observed above 70 °C. Light microscopy revealed no substantial changes in the microstructure of all the stable meat batters cooked to between 50 and 70 °C. Heating to 90 °C changed the microstructure in all meat batters except the hydrogenated palm oil treatments, which still showed nonround fat particles and a less aggregated protein matrix.     

Rheological and Water-Holding Properties of Gelled Meat Batters Containing Iota Carrageenan, Kappa Carrageenan or Xanthan gum

Meat batters containing either 0.5% or 1% iota carrageenan (IC, kappa carrageenan (KC) or xanthan gum (XG) were investigated. Rigidity changes during heating and Instron texture profile analysis indicated textural properties of batters. All treatments exhibited a decrease in water-holding ability (WHA) from 55–70°C. Addition of IC increased WHA, rigidity at 70°C, force-to-fracture and true shear strain. KC increased rigidity at 70°C and was most effective at increasing hardness. XC decreased all textural parameters measured. Gums were specific in affecting textural and WHA properties.     

Walnut, microbial transglutaminase and chilling storage time effects on salt-free beef batter characteristics

Response surface methodology (RSM) was used to assess the effect of walnut content (W), microbial transglutaminase/sodium caseinate (MTG/C) content and storage time (ST) at 3 °C on water- and fat-binding properties, texture profile analysis and dynamic rheological characteristics of salt-free beef batters. Walnut addition favoured the binding properties and elastic modulus (G′) of raw meat batters (20 °C); however, increasing amounts of walnut caused G′ to decrease at 70 °C. MTG/C had no effect on binding properties, but it did cause increases in the hardness of cooked meat batters and in the rheological properties of both raw and cooked samples. The products formulated with MTG/C and stored for up to 11 days at 3 °C presented good gel-forming ability; however, binding properties were poor, so that other ingredients like walnut were needed to improve the binding properties of the products.     

A Comparison of Nonmeat Proteins, Sodium Tripolyphosphate and Processing Temperature Effects on Physical and Sensory Properties of Frankfurters

Frankfurters, with and without 0.5% sodium tripolyphosphate (STPP), containing 3.5% vital wheat gluten (VWC), calcium reduced nonfat dry milk (RNFDM) and soy protein concentrate (SPC) were processed to an internal temperature of 72° or 82°C and compared to an all-meat control. Processing yields, textural profile analysis (TPA) and sensory textural attributes were not different among protein treatments, but SPCand VWG contributed slight-to-moderate off-flavor. VWG and SPC franks were acceptable, but slightly less desirable than the control and RNFDM treatments. Franks processed to 82°C were more desirable, but at the expense of reduced yields. STPP did not affect yields, but increased sensory firmness and TPA fracturability and hardness. VWG, RNFDM and SPC were comparable to the control for most traits studied, but alterations in spice formulation are needed to improve VWG and SPC flavor.     

Kinetic Analysis of the Effect of Some Processing Factors on Changes in Color of Comminuted Meats during Processing

Changes in the psychometric color attributes lightness (L*), hue angle (H*) and chroma (C*) of porcine lean meat batters during processing were kinetically analyzed using the empirical approach of mathematical modeling. The changes during 24 hr storage at 15°C and during heating at 40°C, 50°C, and 60°C were fitted into a model and analyzed for the effects of air pressure during chopping, cutter type and enzyme inhibitors. For changes in L* and C* at 40°C, 50°C and 60°C such kinetic analysis was not possible. Among the factors studied, “air pressure” had the greatest overall effect on color. The effect of “cutter type” was intermediate and that of “enzyme inhibitors” least. The effects found could be ascribed to changes in absorption and scatter properties of the meat batters.     

Contribution of High‐Pressure‐Induced Protein Modifications to the Microenvironment and Functional Properties of Rabbit Meat Sausages

Rabbit meat batters were subjected to high pressure (HP, 100 to 300 MPa for 3, 9, or 15 min) to elucidate their effects on proteins structures, the microenvironment, and the resulting functionalities of the subsequently heated products. To determine these effects, we investigated structural and microenvironmental changes using Raman spectroscopy and also expressible moisture content, textural characteristics, and dynamic rheological properties of batters during heating (20 to 80 °C). Untreated samples served as controls. Analysis of specific Raman spectral regions demonstrated that applications of HP to rabbit meat batters tended to induce the transformation of the all‐gauche S‐S conformation to gauche‐gauche‐trans in the batter system. HP treatment higher than 100 MPa for 9 min promoted secondary structural rearrangements, and molecular polarity enhancement in the proteins prior to cooking. Also, increases of O–H stretching intensities of rabbit meat sausages were obtained by HP treatment, denoting the strengthening of water‐holding capacity. These HP‐induced alterations resulted in improved texture and, perhaps, improved juiciness of rabbit meat sausages (P < 0.05), however they had relatively poorer rheological properties than the controls. Nevertheless, HP treatment, especially 200 MPa for 9 or 15 min, was an effective technique for improving the functionalities of gel‐type products through modification of meat proteins.     

Effect of Gums on Low-Fat Meat Batters

The effects of adding Iota-carrageenan, kappa-carrageenan, guar gum, locust bean gum, xanthan gum, methylcellulose, and a locust bean gum/kappa carrageenan mixture to low-fat, high moisture meat batters were investigated. The methylcellulose treatment showed an increase in weight losses between 60° and 70°C, while other treatments remained similar throughout heating. Xanthan gum and guar gum at 0.2% altered textural parameters as determined by texture profile analysis. Increasing the concentration of xanthan gum decreased batter hardness without affecting batter stability. Sensory evaluation indicated that low-fat frankfurters (11–12% fat) were as acceptable as control frankfurters (27% fat).     

Effect of Heating Rate on Meat Batter Stability, Texture and Gelation

The effects of four heating rates (0.31, 0.51, 1.22, and 1.62°C/min) on the gelation, stability and texture of meat batters containing 2.5 and 1.25% salt were studied. In general, slower heating rates resulted in higher modulus of rigidity (G) values, and salt reduction resulted in lower G values. All the low salt treatments, except the 1.62°C/min treatment, showed a structural breakdown (above 67°C) when the scanning rigidity monitor was used. However, in the texture profile analysis (samples cooked to 50, 60 and 70°C) no structural breakdown was observed. Therefore, special care should be given to interpreting gelation profile results.     

STRUCTURAL FAILURE AND NONDESTRUCTIVE RHEOLOGICAL ANALYSES OF FRANKFURTER BATTERS: EFFECTS OF HEATING RATES AND SUGARS1, 2

The effects of heating rate and sugar type and concentration on the values of frankfurter textural parameters at structural failure were evaluated by a torsion test and a two cycle uniaxial compression test. Structural failure tests indicated that heating rate and sugar concentration had major effects on shear stress; in addition to minor effects on true shear strain. In general, heating rate had a greater effect on stresses and strains than sugar. Torsion and compression tests yielded different values, however, trends due to treatment were similar. The method used for interpretation of texture profile analysis parameters from Instron force-deformation curves had an effect on the statistical analysis results. A thermal scanning rheology monitor nondestructively measured rheological changes during thermal processing. During thermal processing, the major modulus of rigidity increase started at 58°C and the major decrease in energy loss occurred in the 40–60°C range. Unlike structural failure rheological properties, rigidity at 70°C was not affected by heating rate.     

Pressure-assisted gelation of chemically modified poultry meat batters

Changes were induced in the characteristics of poultry meat protein using specific chemical modifiers to investigate the effect of pressurization, prior to heating, on gelation, texture and thermal behaviour of meat batters. Values of hardness and chewiness were higher in cooked meat batters treated with urea than in a salt-only sample, but cohesiveness was similar. The β-mercaptoethanol treatment produced a heat-induced gel with very similar properties to the salt-only gel. The rheological behaviours of salt-only and β-mercaptoethanol samples were very similar, but storage modulus values were higher in samples with urea, which accelerated gelation. The pressure-induced reduction of differences in the textural properties of meat batters suggests that hydrophobic interactions play an important role in heat-induced gelation. Differential scanning calorimetry showed that urea clearly destabilized chicken meat batters, while β-mercaptoethanol had very little influence on their thermal behaviour. Pressurization tended to equalize batters and final cooking definitively equalized them.     

Changes in Physical Properties of Meat Batters During Heating

Techniques for measuring changes in physical properties of meat batters during heating that would be suitable for studying kinetics of gelation were studied. Change in absolute modulus as measured by a dynamic tester was too variable to be useful in studying gelation kinetics. However, differences in consistency show up as significant differences if the absolute moduli of the raw batters. Increase in volume during heating was strictly a temperature effect and the rate of expansion at the same heating medium temperature was the same for a bitter that was gelling compared to a gelled batter in the same mold. Pressure change on heating of a batter at constant volume showed a pattern consistent with expected behavior of proteins on heating. Plots of pressure against temperature were a series of linear sections with the transition points occurring at 33–36°C and at 57–67°C. These temperature ranges are known to start insolubilization of muscle proteins and start solubilizaation of collagen respectively. Plots of unaccomplished pressure change against time on semi logarithmic coordinates was used to calculate a time constant for each stage of the process thereby giving a measure of the rate of gelation.     

鹰嘴豆分离蛋白对减盐猪肉糜凝胶品质的影响

为探究鹰嘴豆分离蛋白(chickpea protein isolate,CPI)不同添加量对2种盐含量(质量分数1.4%和2%)猪肉糜凝胶品质的影响,将猪瘦肉与猪背膘斩拌成肉糜,分别设置不同盐含量和鹰嘴豆分离蛋白的处理组并加热制成凝胶。测定猪肉糜凝胶的色泽、乳化稳定性、质构、水分分布和流变特性。结果表明,在不添加鹰嘴豆分离蛋白的条件下,1.4%食盐质量分数的猪肉糜凝胶的汁液流失和硬度值显著高于2%食盐浓度的猪肉糜凝胶;相同食盐浓度条件下,随着CPI添加量的增加,猪肉糜凝胶的a^*值、b^*值、硬度、弹性、咀嚼性以及不易流动水比例均显著增加(P<0.05),动态流变储能模量G'值升高,汁液流失率显著降低(P<0.05),并在CPI添加量为1.2%时达到最大值或最小值;在相同CPI添加量条件下,1.4%食盐1.2% CPI的猪肉糜凝胶的储能模量G'值高于2%食盐1.2% CPI的猪肉糜凝胶,且2组凝胶的不易流动水比例、乳化稳定性、质构特性无显著差异(P>0.05)。综上,鹰嘴豆分离蛋白的添加能够在降低食盐用量的同时提升猪肉糜的凝胶品质。     

Structure and physical stability of hybrid model systems containing pork meat and superworm (Zophobas morio larvae): The influence of heating regime and insect: meat ratio

Hybrid model systems, containing pork shoulder meat and Zophobas morio larvae in different insect:meat ratios, were subjected to isothermal heating at 70 or 80 °C to investigate how this would affect the rheological behavior, water holding properties and textural properties of these model systems. Meat and insect model systems were also studied for comparison. Rheological and textural characteristics were significantly higher in meat model systems compared to insect and hybrid model systems. Furthermore, insect:meat ratio had little to no effect on the studied attributes of the hybrid model systems. It was also demonstrated that heating the hybrid model systems at 80 °C resulted in similar viscoelastic and water holding properties compared to meat model systems heated at 70 °C. However, even when heated at this higher temperature, the maximum force measured during penetration of the hybrid model systems was still approximately 3 times lower compared to meat model systems.Industrial relevanceThis study investigated the effect of insect:meat ratio and heating temperature on structure formation and water holding in hybrid model systems. The results offer important insights with regard to the composition and processing of hybrid meat products. They indicate that similar viscoelastic and water holding properties compared to meat products may be obtained by applying higher heating temperatures. However, results showed that obtaining the desired texture may pose an important challenge when developing hybrid meat products.     

DSC study on the influence of meat source, salt and fat levels, and processing parameters on batters pressurisation

 Hydrostatic high-pressure/temperature treatments were conducted at low (10 °C) and high temperatures (60, 70, and 80°C) on different types of meat batters. Pressure-induced effects on proteins were intensified by sodium chloride molarity at low and high temperatures. Treatments at 10°C under pressurisation yielded net thermal destabilisation effects on meat proteins pertaining either to muscle or batter systems. Heating at usual cooking temperature of 70°C under pressure yielded net stabilising effects on meat batter proteins. Overheating at 80°C was needed for entire protein denaturation. Pork and chicken meats were very similar in behaviour but chicken batters exhibited relatively higher thermal- and pressure-induced protein denaturation. Both kinds of physical destabilisation/stabilisation of proteins by pressure-induced effects increased with pressure level. Received: 30 December 1999 / Revised version: 14 February 2000     

Effect of salt content on gelation of normal and wooden breast myopathy chicken pectoralis major meat batters

This study investigated the effects of salt content (0–4%) on water holding capacity (WHC), textural characteristics, rheological properties, and microstructure of cooked normal (NOR) and wooden breast (WB) chicken meat batters. Results indicated with 0–2% salt addition, the WB batters had significantly lower WHC and storage modulus (G’) compared with the NORs (P < 0.05). However, these differences were eliminated when salt contents were increased to 3% or 4%. In addition, the NORs formed more regular and pored networks than the WBs (0–2%). Salt level significantly affected the textural properties of both batter types (P < 0.05). The hardness of the WB batters was lower than NORs at all NaCl levels (P < 0.05). Overall, compared with NORs, the WB batters showed inferior gelation properties at salt contents of 0–2%, while increasing salt content to 3–4% can improve the WHC and microstructure of gels.     

Effects of salt reduction on the rheological and gelation properties of beef, pork and poultry meat batters

The gelation and rheological properties of beef, pork and poultry meat batters as affected by salt reduction (2·50, 1·25 and 0·00%) were studied by using a Haake rotational viscometer and a thermal scanning rigidity monitor. Beef batters showed a decrease in shear stress with the decrease in salt levels at both high and low shear rates. Pork batter showed a mixed behavior (no definite trend in shear stress versus shear rate) and the poultry meat batters showed a Bingham pseudoplastic behavior, except for the no-salt treatment. During heating the beef batters showed the highest G values followed by the pork and the poultry meat batters. The rigidity modulus profiles exhibited two major transition temperatures at 47-53°C and at 64-76°C. Beef batter with 2·50% salt developed the highest average G value (16·6 kPa) and the poultry batter with 2·50% salt the lowest (7·3 kPa).     

High pressure processing of meat batters with added walnuts

Various model systems were designed in order to analyse the way in which addition of different levels of walnut (0, 10, 20%) and processing by high pressure (HPP) (400 MPa for 10 min at 10 °C) influenced the physico‐chemical properties of cooked (70 °C for 30 min) meat batters. The addition of walnut increased the fat level and decreased the moisture content in the meat batters. All of the meat batters exhibited good water and fat binding properties. The hardness, cohesiveness, springiness and chewiness of cooked products were reduced by addition of walnut but were unaffected by HPP. Incorporation of nuts in meat products can potentially be used to confer cardiac health benefits.     

Optimisation of freezing process with pressure steaming of potato tissues (cv Monalisa)

Response surface methodology (RSM) was used for determining optimum conditions of the freezing process on pectinesterase (PE) activity, rheological parameters and textural properties in potato tissues. In the process of production of frozen potatoes, the second step of the stepwise blanching prior to freezing was considered as a fixed factor and performed at 97 °C for 2 min as well as the freezing rate in the freezing step itself, which was carried out at −2 °C min⁻¹. The effects of variation in levels of temperature (57.93–72.07 °C) and time (15.86–44.14 min) in the first blanching step on the PE activity were studied using a central composite rotatable design. A Box–Behnken factorial design was used to investigate the effects of simultaneous variation of temperature (60–70 °C) and time (20–40 min) in the first blanching step and steaming temperature (112–122 °C) and time (1–3 min) on rheological parameters and textural properties. Blanching temperature was the independent variable that most influenced either enzymatic activity or rheological parameters. Stationary points showing maximum PE activity had critical temperature and time values of 64.22 °C and 29.37 min before freezing and 64.39 °C and 28.02 min after freezing and steaming of the tissues, and these values were very close to those obtained for some creep compliance parameters. Results show a high correlation between increases in PE activity and tissue firmness below optimum experimental freezing conditions, proving the role of the enzyme as one of the main contributors to the firmness which determines the textural quality of frozen potato tissues. © 1999 Society of Chemical Industry     

Use of time–temperature superposition to study the rheological properties of cheese during heating and cooling

The objective of this study was to investigate the time–temperature superposition behaviour of the rheological properties of cheese during heating and cooling. A standard part‐skim Mozzarella cheese and a fat‐free cheese were used for the study. Fourier transform mechanical spectroscopy was used to simultaneously study the rheological properties over a range of frequencies from 0.08 to 8 Hz while samples were being heated from 10 to 90 °C or cooled from 90 to 10 °C at the rate of 1 °C min^?1. Master curves of storage modulus (G′), loss modulus (G′′) and loss tangent were obtained using a reference temperature of 70 °C.