Characteristics of pressurised pork meat batters as affected by addition of plasma proteins,apple fibre and potato starch

Pork meat (low‐fat) batters were prepared without and with the addition of three non‐meat ingredients: (blood) plasma proteins, (dietary) apple fibre and potato starch. The batters were processed by cooking‐alone (70 °C) and by high‐pressure/temperature combination (400 MPa/70 °C). Protein denaturation and starch gelatinisation through the different processings were followed by differential scanning calorimetry. Batter characteristics such as water holding (weight loss) and different texture parameters (texture profile analysis) were used as quality criteria for comparisons among different formulations and processes. Plasma proteins and apple fibre behaved as inert fillers in both kinds of processed batters. Potato starch effects depended on processing conditions to the extent that these influenced the degree of gelatinisation. In pressurised batters (pressure and heating in sequence), regular preservation effects against subsequent thermal denaturation of proteins were observed. Differential scanning calorimetry revealed that starch was also pressure‐preserved from subsequent thermal gelatinisation, which was confirmed by scanning electron microscopy. The presence of native‐like proteins and ungelatinised starch produced cumulative softening effects in pressurised batters. © 2000 Society of Chemical Industry     

Gelation of chicken batters during heating under high pressure

The gelling process of chicken meat batters, which were heated (75 °C) under atmospheric pressure or high pressure (200/400 MPa), was investigated by determining the hardness of batter, residual denaturation enthalpy, microstructure, and protein secondary structure. The results showed that meat batters heated at 200 MPa showed a similar increase in hardness to heat-only samples, but meat batters heated at 400 MPa showed a texture decreasing tendency after a limited increase. High pressure disrupted the myofibrils, promoted protein denaturation and aggregation in the first stage of heating under pressure treatment. In the second stage of treatment, heating was the main driving force for protein gelation, which was disturbed by hindering the structural transformation of proteins in the presence of high pressure during heating. The effect of 200 MPa on muscle proteins was relatively gentle and had a less negative effect. Excessive high pressure should be avoided when applying heating under pressure for gel-type meat products processing.Industry relevanceHigh-pressure processing is increasingly applied in the meat industry. By combining high pressure with heating, their effects on texture improvement and microbial inactivation can be maximized. In this study, the influence of high pressure on the texture of meat products was analyzed, which showed that excessive pressure would significantly interfere with the thermal denaturation of the protein, thus adversely affecting the formation of the gel structure. High pressure at 400 MPa and above should be avoided when applying heating under pressure for gel-type meat products processing.     

Effects of pre-heating temperature and formulation on porosity,moisture content,and fat content of fried batters

The effect of pre-heating temperatures on moisture and fat contents, and porosity of fried batters was studied. Batter pre-heated at 60 °C showed higher moisture content, lower fat content and lower porosity than non-pre-heated batter and batters pre-heated at 70 and 80 °C. Moisture content, fat content, and porosity at 4 min frying for batters with different pre-heating treatments ranged from 35.08 to 39.37, 3.92 to 5.16, and 13.14 to 45.31 %, respectively. Because of significant reduction in fat content, 60 °C pre-heating temperature was chosen to study the effect of batter formulations on moisture and fat contents, and porosity. Different wheat to rice flour ratios were prepared, and then each batter was pre-heated at 60 °C. Batters with higher wheat flour content showed higher moisture content, and lower fat content and porosity than batters with higher rice flour.     

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.     

A study of the baking process by differential scanning calorimetry

The denaturation of the components of a baked product such as cake or bread can be observed under simulated baking conditions by differential scanning calorimetry. When starch or protein denaturation occurs, an increased flow of heat shows the temperature range over which that process takes place. Experimental results are presented for angel cake. In the absence of sucrose, the egg-white proteins are denatured predominantly near 65 and 85°C. For wheat flour, starch denaturation is observed near 65°C, and protein denaturation over a broad range from 80 to 110°C. In the presence of the concentration of sucrose used in a standard batter, both the starch and the major portion of the egg-white proteins are denatured near 95°C, at approximately the maximum temperature attained by the cake when it reaches maximum volume in the oven. Apparently, the main function of sucrose in an angel cake is to raise the denaturation temperature ranges of the starch and protein. Decreasing the amount of sucrose in batters designed for high altitudes causes denaturation of starch and protein at the lower maximum temperatures attained at those altitudes. This assures formation of a structural framework of denatured starch and protein which will not allow the cake to “fall” after it attains its maximum volume.     

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.     

Role of cathepsin D activity in gelation of chicken meat heated under pressure

The role of cathepsin D activity in gelation of chicken meat batters (400 MPa/30 min/70 °C) heated-under pressure was investigated, using a specific inhibitor, pepstatin, dissolved in dimethyl sulphoxide (DMSO)/acetic acid (9:1 v/v). Thermal treatment (70 °C/30 min) produced less thermal inactivation of cathepsin D activity at 400 MPa than at atmospheric pressure. Heating, under pressure conditions, produced gels which were less hard and chewy than those produced at atmospheric pressure. Irrespective of the pressure, the presence of the inhibitor solvent influenced the thermal gelation of meat batters, facilitating the formation of harder, chewier gels.     

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.     

Thermal Properties of Proteins in Chicken Broiler Tissues

The thermal behavior of breast and thigh muscles, blood and skin tissues of chicken broilers was evaluated by differential scanning calorimetry (DSC). Onset temperature of transition (T_o), maximum thermal transition (T_max) temperatures, and denaturation enthalpy (ΔH) were evaluated. Breast muscle exhibited a complex thermogram with five endothermic transitions at 57°C, 63°C, 67°C, 73°C, and 78°C at a heating rate of 10°C/min. Thigh muscle exhibited only three major transitions at 60°C, 66°C, and 76°C. Thermal curves of isolated protein fractions indicated that the thermal transitions in muscle corresponded to the denaturation of myosin, sarcoplasmic proteins, collagen and F-actin. An increase in the heating rate from 1.0° to 40°C/min significantly elevated the onset temperature of transition and major transition temperatures, as well as the enthalpy of denaturation. Enthalpy of the muscle system heated to various end-point temperatures, cooled and reheated, showed that myosin was completely denatured at 60°C, sarcoplasmic proteins at 70°C and actin at 80°C.     

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).     

High pressure/thermal treatment of meat batters prepared from freeze-thawed pork

Various meat batters were prepared from pork subjected to different freeze–thaw cycles. These batters were pressurized (300 MPa, 30 min) at low, non-denaturing temperature (10°C) followed by heating (70°C) (PLT+H) and at high, denaturing temperature (70°C) (HUPC). Nonpressurized (NP), heated-only (70°C) sample were also produced. Freezing of meat influenced water binding and textural properties of meat batters; the influence on texture was affected by thermal and pressure conditions. Pressure prior to heating produced a coarse, irregular and loose protein matrix, favoring the formation of weaker gel structures than were found in non-pressurized samples. Pressurization at denaturing temperatures reduced the level of protein denaturation induced by the thermal treatment. The resulting gel structures had better water binding properties but were weaker than non-pressurized samples and samples pressurized prior to heating.     

Effect of Cooking on the Thermal Conductivity of Whole and Ground Lean Beef

The probe method was used to measure thermal conductivity of beef through a temperature range of 30–120°C. Thermal conductivity of beef increases with temperature up to 70°C followed by a decrease during the denaturation of proteins and subsequent loss of water. The thermal conductivity of beef again increases with temperature after protein denaturation. The thermal conductivity of cooked beef is lower than raw beef up to about 80°C. The rate of increase for cooked meat thermal conductivity is fairly constant with temperature at a given moisture content. Models based on composition and temperature were found to predict the thermal conductivity of meat during cooking at an average standard percent error of 7%.     

High-pressure-cooked Low-fat Pork and Chicken Batters as Affected by Salt Levels and Cooking Temperature

The application of high pressure (200 and 400 MPa, 30 min) favored water and fat binding properties of chicken and pork batters even at low ionic strength. Textural properties of meat batters (particularly hardness and chewiness, and to a lesser extent springiness and cohesiveness) were influenced by cooking temperature. High pressures influenced the texture of batters, so that pressurized samples were less hard, cohesive, springy or chewy than nonpressurized samples; this effect was not related to on salt concentration. High pressure treatment limited the formation of gel structures, which probably was associated with its preserving effect against thermal denaturation of meat proteins.     

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.     

Apparent Specific Heat of Chicken Breast Patties and their Constituent Proteins by Differential Scanning Calorimetry

Chicken breast meat yielded three endothermic transitions, with peak transition temperatures of 53,70, and 79°C. Comparison with the purified protein fractions indicated that these transitions corresponded to denaturation of myofibrillar (53°C) and sarcoplasmic (70 and 79°C) proteins. The apparent specific heat profile of chicken breast meat was successfully modeled as a weighted average of the apparent specific heat of the constituent proteins. The specific heats of sarcoplasmic protein, myofibrillar protein, and chicken breast meat were strongly influenced by temperature; however, the specific heat of stromal protein was nearly constant across the temperature range considered (i.e., 10 to 100°C).     

大豆分离蛋白添加量对低盐木质化鸡肉糜凝胶特性的影响

探究大豆分离蛋白(soy protein isolates,SPI)添加量对低盐和正常盐木质化鸡胸肉糜凝胶特性的影响.实验设置正常鸡胸肉为对照组.将不同量(0％、1％、2％)SPI分别添加到含1％和2％食盐的木质化和正常鸡胸肉糜中,测定热诱导凝胶的质构特性、颜色、蒸煮损失、水分分布以及蛋白质二级结构等指标.结果表明:相...     

Porosity determination of deep‐fat‐fried coatings using pycnometer (Fried batter porosity determination by pycnometer)

The effect of processing conditions such as frying time and temperature, and batter formulation on pore development in deep‐fat fried chicken nuggets coatings were studied using helium pycnometer method. Chicken nuggets with preformed and laboratory prepared batter coatings were fried at temperatures between 170 and 190 °C for a time range between 0 and 240 s. There was significant (P < 0.05) effect of frying temperature and batter formulation on porosity. Porosity increased with frying time and temperature, and ranged between 2.15 and 47.92% for the preformed batter and 9.96 and 54.76% for the formulated batters. Apparent and bulk densities of the preformed batters increased and decreased with frying time, respectively, but both declined gradually with increasing frying temperature. As the level of rice flour in the formulation increased, apparent and bulk densities also increased. Batter formulation and frying temperature significantly (P < 0.05) influenced the variation in moisture and fat content of the fried batter. Porosity demonstrated positive and negative correlation with fat uptake and moisture loss, respectively, for all the batter coatings.     

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.     

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).     

Effect of Different Processing Methods and Salt Content on the Physicochemical and Rheological Properties of Meat Batters

The physicochemical and rheological properties of raw and cooked batters produced by a chopping or beating process with various amounts of salt content were studied. Various meat batters were made up for this purpose: the batter processed by chopping with 2% salt, by beating with 1% salt and 2% salt, respectively. Compared with the chopping, the beating cooked batters had higher L* value, hardness, G’ value at 80°C, and lower cooking loss. Using the beating process, the batter with 1% salt had lower L* values, hardness, springiness, and higher cooking loss than the 2% salt. From the micrographs, the batters produced by beating process exhibited more uniform and compact microstructure than the chopping. The result of low-field nuclear magnetic resonance exhibited that the batters of beating had higher water holding capacity than the chopping. Overall, the beating process enabled lowering of the salt content, cooking loss, and making the cooked batter more hard and elastic.