Effect of sodium caseinate and κ-carrageenan on binding and textural properties of pork muscle gels enhanced by microbial transglutaminase addition

Response surface methodology was used to investigate the main effects and interactions of sodium caseinate (SC, 0–2%), microbial transglutaminase (MTG, 0–0.6%) and carrageenan (CGN, 0–0.8%) on water binding, textural and colour characteristics of pork gels. Higher κ-carrageenan and sodium caseinate content favored hydration properties and thermal stability, yielding lower cooking loss and higher water holding capacity. Their addition also increased hardness of pork gels, but was unable to improve springiness or cohesiveness. Sodium caseinate either alone or in combination with MTG generally has been found to be inferior to κ-carrageenan for functionality in comminuted meat systems. Although MTG had no effect on binding properties it was found to increase strength of the gels at higher SC levels. Addition of SC and ic-carrageenan significantly altered colour, while no significant influence of MTG on gel colour parameters was observed.     

Effect of high‐pressure treatments prior to cooking on gelling properties of unwashed protein from barramundi (Lates calcarifer) minced muscle

Heat‐induced gelling properties of barramundi minced muscle with 1.5% and 2% added salt were assessed after application of pressures at 300, 400 and 500 MPa at 4 °C (initial temperature) for 10 min and subsequent cooking at 90 °C for 30 min. Whiteness, gel‐forming ability, water‐holding capacity, hardness and springiness of the barramundi gels increased as applied pressure and salt concentration increased. At 2% salt concentration, high‐pressure treatment results in barramundi gels with higher gel strength, mechanical properties and smoother texture as compared to conventional heat‐induced gels (0.1 MPa, 90 °C for 30). At a reduced salt concentration (1.5%) and pressure ≥ 400 MPa, the quality (gel strength, water‐holding capacity, hardness and springiness) of pressurised cooked gels is comparable to those heat‐induced gels with 2% added salt, but the microstructure is smoother. Scanning electron microscope images of pressurised cooked gels showed dense and compact network with smoother surface than those of heat‐only‐induced gels. Thus, application of high‐pressure treatment prior to cooking could be an effective method to enable reduced salt concentration in barramundi gels.     

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.     

Effect of thermal treatment on the texture and microstructure of abalone muscle (Haliotis discus)

The texture and microstructure of edible abalone meats were studied during heat treatments from 50 to 100°C for 60 min. No increase in extractable soluble collagen content was observed below 80°C, but a 9-fold increase was observed at 100°C. SDS-PAGE showed that extractable myosin heavy chains and paramyosin contents reduced significantly at 80°C, and disappeared completely at 100°C. The shear force increased slowly from 50 to 70°C, but relaxed back to the initial level at 100°C. Rapid reduction of hardness was observed at 50°C, minimum hardness was obtained at 100°C. Springness, cohesiveness, chewiness, and resilience were enhanced to maximum levels at 70, 90, 70, and 90°C, respectively. Optical micrographs and transmission electron microscope showed a significant increase of intermyofibrillar gaps at 90°C and broken fibers at 100°C. Results suggested that 80°C might be a suitable temperature to produce ready-to-eat abalone products.     

Pork Skin Connective Tissue Gel Utilization in Reduced-Fat Bologna

This study determined temperature (50°, 60°, 70° and 80°C) and time (0.5, 1.0, 1.5 and 2.0h) factors that enhanced the water binding of pork skin connective tissue (PCT); the functionality of added water (AW, 100–600%, w/w) PCT gels; and attributes of bologna containing 10-30% addition of 100–600% AW PCT gels. Heating (70°C) PCT increased water binding. Gels (100–600% AW) were formed by heating PCT (70°C) for 30 min. Higher AW levels increased (p < 0.05) gel moisture content, while decreasing fat, melting points, collagen content, and hardness. Addition of PCT gels in bologna decreased (p < 0.05) hardness and increased juiciness, indicating the potential of PCT gels as water binders and texture-modifying agents.     

Binding and textural properties of beef gels processed with κ-carrageenan, egg albumin and microbial transglutaminase

The combined influence of κ-carrageenan (κ-CGN, 0.5%) and egg albumin (EA, 2%) on quality characteristics of beef gels processed without or with 0.5% microbial transglutaminase (MTG) was investigated. Beef gel properties were determined by measuring textural, hydration and colour characteristics. κ-Carrageenan favourably affected hydration properties and thermal stability, yielding lower cooking loss, purge and expressible moisture. It also increased hardness and fracturability of beef gels, but was unable to improve springiness or cohesiveness. Egg albumin either alone or in combination with MTG generally has been found to be inferior to κ-carrageenan for functionality in comminuted meat systems. Addition of EA produced an increase in lightness and yellowness, and a decrease in redness of beef gels, while the presence of κ-carrageenan resulted in lower L(?) and b(?), and higher a(?) values. No significant influence of MTG on gel colour parameters was observed.     

Physical analysis of friction cooked RTE snacks

Extrusion is widely applied for production of ready to eat snacks. The existing technology is capital intensive and requires preconditioning the raw grains before extrusion, dedicated drying after extrusion and post extrusion addition of fat and sugar where required. A novel technology, friction cooking, has been developed to greatly lower capital costs and overcome the limitations of conventional extrusion. The production conditions (temperature and moisture content) and resulting physical properties from eight friction cooked raw grains were compared to the equivalent properties of conventionally extruded products from these grains. Properties were expansion ratio, bulk density, hardness and colour. Friction cooking temperatures were lower (60–98 °C versus about 150 °C), and products were softer but with a lower expansion ratio and higher densities. In friction cooking colour differences between raw grains and cooked product were minor. Many of these differences were attributed to lower temperatures and moisture contents in the friction process.     

Microbial transglutaminase and caseinate as cold set binders: Influence of meat species and chilling storage

The effect of microbial transglutaminase/sodium caseinate (MTG/C) systems on meat batter characteristics (water binding and textural properties of raw and cooked products) was studied in the presence of NaCl (1.5 g/100 g) and sodium tripolyphosphate (0.5 g/100 g), and storage time (96 h at 3 °C) for three meat species (pork, chicken, lamb). Samples prepared from pork and lamb with only MTG/C (no salts) had the highest cooking loss (CL) values, about 23 and 29 g/100 g, respectively; for chicken, the CL was less than 13 g/100 g. Hardness (Hd) and chewiness (Cw) generally tended to be higher in cooked samples containing MTG/C than in samples containing only salts. Products combining salts and MTG/C had higher (P<0.05) Hd and Cw. The efficiency of the MTG/C system as a texture conditioner of cooked products varied with the meat source.     

Effect of Konjac Glucomannan (KGM) and Carboxymethylcellulose (CMC) on some Physico-Chemical and Mechanical Properties of Restructured Gilthead Sea Bream (Sparus aurata) Products

The development of restructured fish products and the application of new food ingredients have been used to create attractive new products and also to upgrade low-value species. The aim of this study was to evaluate the effect of konjac gum (KGM) and carboxymethylcellulose (CMC) fibres on the mechanical and physico-chemical properties of microbial transglutaminase treated restructured fish products from gilthead sea bream as well as to evaluate the effect of heat treatment and storage time. Water holding capacity, mechanical properties and colour attributes in fresh and heat-treated samples after 15 days of cold storage were measured. Results showed that these edible gums could be appropriate for making restructured products obtained from gilthead sea bream. In fresh formulations the addition of 10 g?kg^?1 of KGM or 10 g?kg^?1 of CMC presented a significant effect (p?≤?0.05) on water activity for fresh samples and the lowest value was obtained for 10 g?kg^?1 of KGM (0.975?±?0.002). Water holding capacity and adhesiveness increased due to the presence of these gums in fresh and heat-treated samples. For heat-treated samples, KGM significantly reduced (p?<?0.05) hardness, cohesiveness and chewiness. Cryo-scanning electron microscopy revealed different structures for gels containing fibres. The use of these fibres did not induce significant changes in colour parameters. Fresh or heat-treated samples stored for 15 days at 4°C showed changes in relation to the parameters investigated.     

Ultrastructure of low-fat ground beef patties with added whey protein concentrate

Microstructure of gels formed at 71°C from different mixtures of beef myofibril protein (BMP; 6.1% protein) and whey protein (WP) were studied by transmission electron microscopy (TEM). At a ratio of30:10 (w/w) of whey protein concentrate (WPC; 79.5% protein) to BMP, WP formed a network of aggregated clusters in which beef myofibril proteins were embedded. WP apparently acts as a filler and possibly as a cementing agent for the meat pieces. At a lower ratio of 10:30 (wl w), the WP aggregates occupied and increased the interstitial spaces between the myofibril protein and reinforced the network. The location of WP in the interstitial spaces might explain its water binding ability in beef patties formulated with WP and water. WP protected the beef myofibril protein structure during heating as less disintegration in the Z-line was observed in gels with WP compared to the control. Low-fat (10% fat) ground beef patties with added 10% water and 1–4% whey protein concentrate (WPC), cooked to three different internal temperatures (60, 70 and 80°C), were evaluated for their cooking characteristics and examined by TEM. For all levels of addition, WPC improved the cooking yield compared to a non-formulated control of 10% fat. Fat retention was also improved at the highest level of WPC addition. The increased cooking yield was shown to be caused principally by the better water retention. The textural parameters, hardness and chewiness, were not affected by WPC addition but increased with increasing cooking temperature. These temperature-induced changes were matched by marked changes to the ultrastructure of the meat products.     

Effect of chitosan and microbial transglutaminase on the gel forming ability of horse mackerel (Trachurus spp.) muscle under high pressure

This paper examines the effect of high pressure treatment (300 MPa, 25 °C, 15 min), combined with a prior or a subsequent setting step (25 °C, 2 h), on gelling properties of mackerel mince containing 1.5% chitosan and/or 0.02% microbial transglutaminase (MTG). Rheological analyses (folding test, puncture test and stress–relaxation test), scanning electron microscopy, protein solubility and thiobarbituric acid reactive substances (TBARS) were performed in gels. Chitosan did not substantially modify rheological and microstructural properties of gels obtained under high pressure conditions but reduced lipid oxidation. It exhibited only a slight reduction in gel elasticity, whereas MTG, alone or in combination with chitosan, led to an increase in hardness and to a considerable decrease in elasticity and breaking deformation. No evidence of synergism between chitosan and MTG was found. Pressurization with previous setting induced more deformable and stronger gels and reduced the amount of TBARS as compared to high pressure without setting, or with a setting step following pressurization.     

Effects of different objective functions on optimal decision variables: a study using modified complex method to optimize hamburger cooking

Hamburger patties are prepared from ground beef and cooked to obtain a safe product before consumption. Cooking process eliminates microbial hazards and results in certain quality changes (e.g., cooking loss, textural changes). All these changes can be used as an objective function to achieve an optimum cooking process, but their effects on decision variable (e.g. process temperature profiles) of the optimization should be known. The use of different objective functions (minimization of cooking losses, hardness, chewiness, and shear to work) was compared to see their effects on plate temperature profiles for double-sided contact cooking. Modified Complex Method was applied as the optimization procedure. Lower and higher limits of grill temperatures (177–220°C) were explicit constraints while lethality and temperature at the patties center (F₀⩾15 s; T_c⩾71°C) were implicit constraints. The objective functions and implicit constraints were determined using a previously developed numerical heat transfer simulation model. Constant temperature profiles (decision variables) for different objective functions at different processing times (121 and 130 s) were determined. Same decision variables were found regarding the different objective functions (198.3°C and 184.1°C) for the given processing times.     

Effect of Hardness of Plastic Fat on Structure and Material Properties of Fish Protein Gels

Textural modification of fish protein gels by incorporation of plastic fat was investigated by examining the effect of the physical properties of fat on the structure and the material properties of protein gels. Material properties of fat-containing protein gels were influenced largely by fat distribution pattern which was, in turn, affected by fat hardness. Both compressive and shear forces reached their maximum when fat of 1.8 cm^–1 hardness index (HI) was added at a level of 15% (fat/muscle). Addition of medium hard fat (0.54–0.78 cm^–1 HI): (1) prevented a sponge-like texture development by improving freeze-thaw stability; (2) increased plastic deformation, thus making cooked gels less rubbery; (3) overcame the weakening of texture caused by cooking at the critical zone (60–70°C); and, (4) minimized the variations in textural strength resulting from cooking.     

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 SETTING CONDITIONS USING MICROBIAL TRANSGLUTAMINASE DURING OBTENTION OF BEEF GELS

Microbial transglutaminase (MTG) is a food additive widely used to improve the mechanical properties of beef, poultry and fish gels. The aim of this study was to determine the effect of incubation temperature on the mechanical properties of restructured beef gels treated with MTG. The restructured beef gels were obtained by adding 0.0% (untreated) or 0.3% MTG. Three incubation temperatures (40, 50 or 60C) for 30 min were used, followed by cooking at 90C for 15 min. Control samples without incubation were also prepared. Changes in the mechanical properties (texture profile analysis and puncture test), color attributes, expressible water and cooking loss were determined. Results indicated that the maximum mechanical properties can be obtained by incubating beef pastes at 50C for 30 min with minimal effect on color, expressible water and cooking loss when 0.3% of MTG is added.

PRACTICAL APPLICATIONS

Meat and poultry are considered nonsetting proteins, and consequently, an incubating treatment to allow optimal cross-linking has not been considered, and the products are usually obtained by direct cooking. Our results showed that beef gels containing 0.3% of microbial transglutaminase incubated at 50C showed higher mechanical properties than control gels without incubation. These results could be useful to improve the mechanical properties of beef gels.     

Quality Evaluation of an Ohmically Cooked Ham Product

Selected parameters (cooking loss, instrumental colour and texture and sensory quality) of a brine-injected pork muscle cooked by a novel and rapid ohmic cooking protocol were examined and compared with those obtained in conventionally cooked samples. Ohmic samples were cooked using either a low-temperature long-time (LTLT) protocol (2 min equilibration, 5 min ohmic heating to 70 °C, 8 min holding) or a high-temperature short-time (HTST) procedure (2 min equilibration, 6 min ohmic heating to 95 °C) performed within a hot air cabinet set at 80 °C (LTLT) and 100 °C (HTST). Conventional cooking (steam oven at 80 °C for 120 min) was conducted to a core temperature of 70 °C. The LTLT treatment gave a much lower cooking loss value (4–5% lower, p < 0.05) than the other treatments, though the full magnitude of this difference was not completely reflected in the proximate composition of the cooked products. Ohmically cooked ham showed a significantly (p < 0.05) lighter surface colour with Hunter L values of 65.3 (LTLT) and 63.5 (HTST) relative to the control (61.4). Texture profile analysis (TPA) indicated a significant difference (p < 0.05) in hardness (N) especially between the HTST surface (82.1 N) and the conventional centre (58.8 N). Although the ohmic cooking protocols yielded products with quite acceptable eating qualities, sensory evaluation found the overall quality of the conventionally cooked ham to be significantly (p < 0.05) superior, indicating that further optimisation of the ohmic cooking protocols would be required prior to any commercial adoption.     

甲基纤维素添加量对低盐肉糜凝胶特性的影响

将甲基纤维素(methyl cellulose,MC)作为替代物加入肉糜中等量替代食盐,采用5个不同MC添加量(0％、0.4％、0.8％、1.2％、1.6％)即肉糜中的食盐质量分数分别为2％、1.6％、1.2％、0.8％、0.4％.通过测定肉糜凝胶的蒸煮损失率、色泽、质构、低场核磁共振横向弛豫时间(T2)以及流变特性,...     

Comparison of the Thermostability of Red Hake and Alaska Pollock Surimi during Processing

Thermostability of red hake (Vrophycis chuss) mince and its temperature-dependent gel-forming properties were determined while using Alaska pollock (Theragra chalcogrumma) for comparison. Fish mince and surimi were subjected to various washwater, chopping and setting/ cooking temperatures, cooking times at varying salt concentrations and moisture levels. The optimal temperatures for washing and chopping were 15°C and 12°C for red hake and 10°C and 4°C for pollock, respectively. All treatments significantly affected gel properties. For red hake gels, 77% moisture, 2.0% salt, and a 40°C preheat-setting temperature produced the most cohesive gel. Gels of both red hake and pollock gradually became less cohesive with extended cooking time. The results suggest that red hake is more thermally stable than pollock.     

Characteristics of High- and Low-Fat Bologna Sausages as Affected by Final Internal Cooking Temperature and Chilling Storage

A study was made of the effect that final internal processing temperature (63, 70 and 78°C) and chilling storage (2°C) exerted on the characteristics (cooking loss, purge loss, colour, Instron texture profile analysis) of high-fat (242 g kg⁻¹) and low-fat (100 g kg⁻¹) bologna sausage. High-fat sausages were harder and chewier than low-fat sausages. Lower fat contents were accompanied by a significant reduction in the cooking loss and purge loss. Binding properties were not affected ( P> 0·05) by final internal cooking temperature. In general, Hunter colour parameter a values were higher in low-fat samples subjected to a high final internal cooking temperature than in those cooked up to only 63°C. High internal temperatures produced harder meat emulsions, an effect which was more pronounced in high-fat than in low-fat sausages. Cohesiveness and springiness of sausages was not affected ( P> 0·05) by heat treatment. There were no major variations in textural parameters as a result of chilled storage.     

TEXTURE PROFILE PARAMETERS OF COOKED FRANKFURTER EMULSIONS AS INFLUENCED BY COOKING TREATMENT2

Texture profile parameters of frankfurters were found to be generally related to cooking temperatures, except for degree of elasticity, hysteresis loss, and work ratio. Cohesiveness, elasticity, gumminess, and chewiness all were polynomial functions of cooking temperature and were smallest at 70-75° C where physico-chemical changes in proteins important to texture development appeared to be occurring. Hardness, compression energy of first bite, brittleness, apparent moduli of elasticity, stress at 20% compression and strain energy of compression per unit volume were all linearly related to the cooking temperature. Texture profile parameters were higher for samples with higher protein and lower moisture contents at all cooking temperatures.