Rheological and Stability Transitions in Meat Batters Containing Soy Protein Concentrate and Vital Wheat Gluten

Physical/rheological properties of meat batters during heat-processing were studied. Vital wheat gluten (VWG) and soy protein concentrate (SPC) were incorporated into meat batters which were heated to 40, 50, 60 and 70°C and held for 0, 30 and 60 min. Amounts of fat and aqueous fluid released during heating were determined. A two-cycle compression test and shear modulus determination were used to evaluate rheological changes. VWG and SPC did not have any significant effect on either stability or textural changes. There was a significant interaction between temperature and time for stability and textural characteristics. Significant changes in rheological and stability properties of meat batters occurred in the 50–70°C region. Shear modulus showed a major increase at 54–57°C.     

Thermal and dynamic rheological properties of wheat flour fractions

A commercial high gluten flour (HGF) was fractionated into prime starch (PS), tailing starch (TS), and gluten (G). Fractions were examined alone or in various combinations. Dynamic rheological properties of samples were measured in an oscillatory rheometer (strain 0.02; frequency 0.1 Hz) during heating at 1°C/min. Thermal characteristics of samples were determined by differential scanning calorimetry (DSC) at a heating rate of 10°C/min. The loss (G″) and storage (G′) moduli of PS and mixed G/PS, G/TS, and G/PS/TS increased after 60°C, reaching peak values (e.g. 81, 301, 313, and 3000 Pa in G′, respectively) around 75°C after which the moduli decreased. HGF showed a steady increase in G′ from 32 to 2490 Pa as temperature increased from 65 to 90°C, indicating continuous formation of elastic networks. Cooling increased G′ for G/PS/TS, decreased G′ for HGF, and produced no rheological transitions for all samples. TS and G alone did not exhibit appreciable viscoelastic responses to the heating and cooling temperatures. DSC measurements revealed a major endothermic transition in HGF. This transition, with a peak around 60°C, was due to starch gelatinization. The presence of G or TS resulted in reduced melting enthalpies of starch in the PS fraction. Gluten or TS fractions alone or in combination did not exhibit any endothermic transitions.     

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.     

Functional modification of vital wheat gluten with corn syrup using hydrothermal treatment

Functional properties of gluten modified using hydrothermal treatment were compared with those of vital wheat gluten (VWG). Gluten slurry was jet cooked under pressure in the presence of corn syrup (CS) at different temperatures (121 and 149 °C) for different times and then spray dried. Foaming properties for all samples (treated and untreated) at different pHs showed that, although the optimum pH was 5, at this pH the treated gluten samples displayed reduced foaming properties as compared with the control, whereas at all other pHs there was an increase in foaming properties. The sample treated with CS at 121 °C (JC121w/cs) showed the highest viscosity and elasticity increase among all treated samples. Emulsifying properties were adversely affected by an increase in temperature of treatment, whilst addition of CS helped to restore emulsion stability (ES). The sample VWG with CS (Cont.w/cs) at pH 3 showed maximum ES. In general, samples after treatment showed increased solubility. The hydrophilic but non‐ionisable sugar hydroxyl groups affected the functionality at lower pH. Molecular changes were followed by size exclusion high‐performance liquid chromatography (SE‐HPLC) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). Samples subjected to the lower temperature (121 °C) showed a shift of the molecular weight distribution to higher values in the HPLC profile, consistent with higher viscosities for this treatment. For the same samples, SDS‐PAGE of the reduced protein exhibited a decrease in the intensity of bands corresponding to high‐molecular‐weight glutenin subunits, complementing the fact that large‐molecular‐size polymers are involved during protein modification. Copyright © 2005 Society of Chemical Industry     

Batter rheology and bread texture of sorghum‐based gluten‐free formulations modified with native or pregelatinised cassava starch and α‐amylase

The influence of α‐amylase (0–0.3 U g^?1) on the crumb properties of gluten‐free sorghum batter and bread, respectively, was investigated. The formulations were modified using native or pregelatinised cassava starch (i.e. batter A – 17% pregelatinised starch, 83% sorghum, 100% water fwb; batter B – 17% native starch, 83% sorghum, 100% water fwb; and batter C – 30% native starch, 70% sorghum, 80% water fwb). The batters had solid viscoelastic character with the storage modulus predominant over the loss modulus. Storage moduli of batter A decreased with increasing angular frequency, whereas the moduli of batters B and C were independent from the angular frequency. Increasing enzyme concentration did not affect the loss factors of the batters. Batters’ resistance to deformation, from highest to lowest, followed the order C > A > B. Increasing enzyme concentration decreased crumb firmness, cohesiveness, springiness, resilience and chewiness but increased adhesiveness. Overall, breads containing native starch had better crumb properties (i.e. springier and less firm, chewy and adhesive) than breads containing pregelatinised starch.     

Influence of gluten on the viscoelastic properties of starch pastes and gels

Viscoelastic properties of dispersions (60–300 g kg⁻¹) of gluten (G) and wheat starch (S) blends (0 < G/S < 0·20) and wheat flour have been studied during heating and cooling. In both cases, the moduli followed power law relationships with concentration. The temperature at which the transient network development began, caused by granule–granule interactions, decreased as the concentration increased and increased with an increase in the proportion of gluten. Moreover, gluten weakened the strength of both starch pastes and gels, as shown by the lower values of the moduli. The viscoelastic behaviour of flour samples reflected the role played by internal lipids. A structural model is proposed in order to explain the influence of gluten on the rheological behaviour of starch pastes and gels. © 1998 Society of Chemical Industry.     

A Technique to Measure Binding Properties of Non-meat Proteins in Muscle-Juncture Formation

Junctures of meat containing five nonmuscle protein products were made by use of a technique in which cubes of porcine longissimus muscle were oriented according to three fiber directions and joined together with certain nonmuscle protein products to form blocks. These blocks were cooked (72°C) and their junctures evaluated for viscoelastic properties. Viscoelastic properties were not different (P > 0.05) among all comparisons of junctures except for those made with sodium caseinate and no protein product (controls) which did not form a juncture. Junctures made with plasma protein (PP) or egg albumin (EA) had higher numerical values for viscoelastic properties than those made with either isolated soy protein (ISP) or vital wheat gluten (VWG). VWG-junctures had higher numerical values for viscoelastic properties when cooked to 93°C than when cooked to 72°C. The technique of preparing muscle junctures was satisfactory, but techniques for Instron stress-relaxation measurements of junctures need improvement.     

Influence of double enzymic hydrolyses on gluten functionality

Functional properties of chemically deamidated and/or double enzymically‐treated gluten were studied. Performances of the modified glutens were compared to those of egg white proteins, casein, deamidated gluten and gluten submitted to deamidation plus single enzymic treatment. Higher nitrogen solubility index (>90%) was obtained after treatment of the gluten with the sequence pepsin + alcalase and deamidation + pepsin + papain. The sequence pepsin + papain has permitted the production of a gluten with foaming properties close to those of egg white. Deamidation + papain treatment leads to interesting emulsifying properties although different from those of casein. The results show that modified glutens present thresholds in the degree of enzymic hydrolysis (DH) for foaming and emulsifying properties (respectively 1.3% and 2.0%). For higher DH the stability decreases. © 1999 Society of Chemical Industry     

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.     

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.     

Dynamic Rheological Properties of Cake Batters Made from Chlorine-Treated and Untreated Flours

When cake batters prepared with chlorine (Cl₂)-treated and untreated flours were heated in the Rheometrics Dynamic Spectrometer (RDS), elasticity G′ increased between 90°C and 100°C for the Cl₂-treated sample and not for the untreated sample. Therefore, at 100°C, the batters prepared with Cl₂-treated flours had a much higher G′ than the batter prepared from untreated flours. Flour-water systems prepared with Cl₂-treated and untreated flours showed no difference in G′. This inferred that there was an interaction with at least one formula ingredient. Defatting both Cl₂-treated and untreated flours did not alter the RDS results.     

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.     

Effect of β‐Glucan–Rich Barley Flour Fraction on Rheology and Quality of Frozen Yeasted Dough

Research has shown that prolonged frozen storage of bread dough reduces the quality of the end product. In this study, the effect of air‐classified barley flour fraction rich in β‐glucan (approximately 25%) on rheology and quality of frozen yeasted bread dough was investigated. Wheat flour (W) was replaced by air‐classified barley flour fraction (B) at 10% without or with 1.4% vital gluten to produce β‐glucan enriched barley dough (WB) or barley dough plus gluten (WB + G). Dough products were stored at ?18 ºC for 8 wk and their rheological properties were investigated weekly. During frozen storage dough extensibility increased, while elastic and viscous moduli decreased. Differential scanning calorimeter and nuclear magnetic resonance data indicated that WB and WB + G dough products contained approximately 10% less freezable water and 9% more bound water compared to the control dough (W). β‐Glucan enriched dough also exhibited less changes in gluten network as shown by SEM photographs. The addition of air‐classified barley flour fraction at 10% in frozen dough reduced deterioration effects caused by frozen storage via minimizing water redistribution and maintaining rheological properties of frozen dough.     

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.     

Steady and oscillatory shear behaviour of semi-concentrated starch suspensions

The viscoelastic moduli G’ and G” of aqueous suspensions with 40% (w/v) normal corn starch (NCS) and waxy corn starch (WCS) were determined by oscillation rheometry. The oscillatory shear flow experiments at heating from 30° to 75 °C and maintaining at this temperature showed changes from a behaviour predominant viscous (G”>>G’) to predominant elastic (G’>G”) for both starches at 60.5 °C for WCS, respectively 70,85 °C for NCS, WCS having higher values of G’ and G” as NCS. After the gelatinisation temperature was attired, NCS showed no significant changes, both moduli remaining relatively constant. Peaks of both moduli G’ and G” were obtained for WCS at its maintaining at 75^oC, these changes being attributed to the changes in the amylopectin structure in the absence of amylose for this starch type. The frequency influenced the results; analysis at constant low frequency (10 s^-1) gave big oscillations during the measurements and made the analysis impossible, whereas frequencies as 50 s^-1 or 100 s^-1 gaves reproducible and similar results. The shear flow measurements realised at angular frequencies ω from10^-1 to 10³s^-1 at 25^oC showed that changes from a behaviour predominant elastic (G’>G”) to predominant viscous (G”>>G’) occurred when ω attired the values 10 s^-1 for WCS and 3 s^-1 for NCS. The calculation of the ‘Power-Law’ parameter B showed that NCS forms a physical gel structure, whereas WCS behaves as a covalent gel in the frequency domain 10^-1 to 10 s^-1 and as physical gel in the frequency domain 10 to 10² s^-1.     

Rheological Properties and Microstructure of Acid Milk Gels as Affected by Fat Content and Heat Treatment

Gels were made from recombined milks containing 0, 1.5 or 3.5% fat that were heated at 75, 80 or 90°C for 30 min, followed by acidification with glucono-8-lactone at 30°C. The rheological and microstructural properties of acid gels were investigated using dynamic low-amplitude oscillatory rheology and confocal scanning laser microscopy (CSLM). Heating milks, at temperatures ≥80°C, increased the storage moduli (G′) and decreased the gelation time. Recombined milks containing high fat (3.5%) had higher G′ than gels made from low-fat or skim milk. Milk heat treatment resulted in gels with a cross-linked microstructure. Recombined fat globules appeared to be embedded in the protein matrix.     

Reduced Fat, High Moisture Beef Frankfurters as Affected by Chopping Temperature

Six treatment combinations were studied to determine the effects of initial temperature (0, 15, 30°C) and endpoint chopping temperatures (0, 15, 30, 45°C) on texture and stability of reduced fat, high moisture beef frankfurters. Textural properties (raw batter, frankfurter) and purge loss were determined over 8 wk storage. As endpoint chopping temperature increased, batter stability and shear force decreased. In most samples, initial temperature did not affect texture or stability. Endpoint chopping temperatures of ± 15°C resulted in most stable batters. Chopping > 15°C lowered product quality.     

Dynamic Rheological Properties of Mozzarella Cheese During Refrigerated Storage

Storage (G′) and loss (G″) moduli of low-moisture, part-skim Mozzarella cheese were determined at 10 and 20°C during 1 mo of refrigerated aging. At both temperatures, G′ was always greater than G″. Averaged over aging, G′ increased from 90 to 630 and G″ from 44 to 52 kPa at 10°C, and at 20°C G′ increased from 28 to 190 and G″ from 14 to 53 kPa for the frequency range 0.005-20 Hz. Averaged over frequency, both G′ and G″ decreased about 20% at 10°C and 25% at 20°C during aging. Relaxation spectrum, computed from shear relaxation data, was used to calculate the G. The calculated values of G′ were in good agreement with those determined experimentally. These data help predict and compare melting behaviors of such cheeses.     

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.     

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.