Synergistic action of transglutaminase and high pressure on chicken meat and egg gels in absence of phosphates

The effects of simultaneous application of microbial transglutaminase (MTGase) and high pressure (HP) (500, 700 and 900 MPa/40 °C/30 min), only pressure under the same conditions or heat (75 °C/30 min) were investigated on chicken batters with the addition of egg components and without phosphates. MTGase gels (700 and 900 MPa) showed marked increases in textural parameters compared to gels without enzyme (NE) or those obtained by heat. The addition of enzyme did not show differences between gels obtained at 700–900 MPa; however, gels obtained at 500 MPa were darker and more reddish than those obtained by heat. MTGase gels were more homogeneous and compact. Thermal analysis revealed that pressure levels above 700 MPa caused as much denaturing as did heat. The microstructure and texture of MTGase gels suggest that a higher amount and heterogeneity of crosslinks was produced when meat and egg proteins were treated in the presence of MTGase under specific conditions of pressure.     

Effect of laccase and transglutaminase on the textural and water-binding properties of cooked chicken breast meat gels

The effects of laccase and transglutaminase (TG) on the firmness and weight loss of cooked chicken meat homogenate gels were investigated at laboratory scale. The salt, trisodium pyrophosphate and meat contents were also used as variables. Laccase decreased firmness and increased weight loss of phosphate-free, low-meat (65%) and low-salt (1%) gels, although it modified myosin and troponin T and reacted with isolated myofibrils. By applying both low-salt (1%) and low-phosphate (0.17%) amounts, gel firmness decreased and weight loss increased (p<0.05) greatly. A high dosage of TG significantly improved (p<0.05) the strength of phosphate-free, low-meat and low-salt homogenate gels compared to the corresponding no-enzyme controls. TG improved gel firmness of the low-meat homogenate to the level of the homogenate containing 75% meat. Weight loss was increased significantly (p<0.05) in all cases when the high-TG dosage was used. Enzymes were not capable of improving either texture or water-holding capacity in the low-salt–low-phosphate system. The firmness and cooking loss of the chicken meat products containing different amounts of meat, salt and TG were investigated at pilot scale. Under the conditions and dosages used, TG was capable of improving (p<0.05) firmness of the products without a significant reduction in water-holding capacity.     

高静压对鸡肉凝胶品质影响的试验研究

通过单因素试验,在压力100~400 MPa、保压时间15 min、室温条件下,考察高静压对低盐(食盐添加量1%)鸡肉凝胶色泽、pH值、持水性与质构品质的影响。研究结果表明:200 MPa以上的高静压可导致鸡肉凝胶亮度的显著下降、以及凝胶硬度、弹性和咀嚼性的显著增加;300 MPa以上的高静压可引起鸡肉凝胶pH值和黏结性的显著升高(P<0.05);100 MPa与300 MPa压力使鸡肉凝胶的蒸煮损失率CL低于对照组,而200 MPa压力导致CL升高(P<0.05);100~400 MPa的高静压对鸡肉凝胶的保水性无显著影响(P>0.05)。因此,300 MPa的高静压可形成高硬度、高弹性与高黏结性、低CL值的低盐鸡肉糜凝胶制品。     

转谷氨酰胺酶和超高压技术在重组肉制品中的应用

介绍重组肉制品的定义、分类及加工原理,并对转谷氨酰胺酶和超高压技术在重组肉制品中的应用和研究进展进行综述,以期为转谷氨酰胺酶和超高压技术在重组肉制品加工中的应用提供参考。     

Effect of non-meat proteins on hydration and textural properties of pork meat gels enhanced with microbial transglutaminase

The combined effect of incorporation of four non-muscle proteins, NMP (blood plasma, BP; sodium caseinate, SC; soy protein isolate, SPI; gelatin, G) at 2 g/100 g levels on hydration and textural characteristics of pork gels processed without or with 0.6 g/100 g microbial transglutaminase preparation (MTG) was investigated. Addition of SC and BP most favourably affected hydration properties and thermal stability, yielding lower cooking loss and expressible moisture for pork gels. Interactions between NMP and MTG were observed. Improvement of gel strength by addition of transglutaminase was observed for treatments containing SC and BP but not G nor soy isolate. Of the four proteins tested SC was found to be a superior substrate for MTG in enhancing textural properties of a gelled meat system. None of the tested ingredients was able to yield gel cohesiveness equivalent to the control containing 8% muscle proteins. Results of this study indicate a potential for using MTG to improve or modify the functional and textural properties of investigated food proteins (SC and BP in particular) in comminuted meat products.     

Antioxidant active packaging for chicken meat processed by high pressure treatment

Patties made of minced chicken breast and thigh packed in standard vacuum-packaging (C) or in antioxidant active packaging (AP) were subjected to high pressure treatment (800 MPa, 10 min, 5 °C) and subsequently stored for 25 days at 5 °C. Lipid oxidation was studied at the surface (S) and the inner (I) parts of the meat patties. The lipid oxidation was higher in the surface part and the active packaging was able to delay it up to 25 days. The lipid oxidation was limited in the inner part of the meat patties and restrained at the surface of the active packaging. It was found that the effect on lipid oxidation by high pressure may not be explained solely by cell membrane damage, as radicals were formed in the meat during the pressure treatment.     

Application of microbial transglutaminase in meat foods: A review

Microbial transglutaminase (MTG) is an enzyme isolated from a variant of Streptomyces mobaraensis that forms covalent cross-links between protein molecules. Studies are being conducted since last two decades on utilization of MTG in meat foods to improve their characteristics, such as gelation, water-binding, emulsion stability, purge loss, cooking loss, etc. MTG is one of the important topics of interest in meat processing industry due to its advantages in practical utilization and commercial exploitation. This review will discuss about the overall applications of MTG in manipulating the functional properties of meat and meat products by means of various processes such as restructuring, value addition, etc.     

Aroma development in high pressure treated beef and chicken meat compared to raw and heat treated

Chicken breast and beef muscle were treated at 400 and 600 MPa for 15 min at 5 °C and compared to raw meat and a heated sample (100 °C for 15 min). Vacuum-packed beef meat with a smaller fraction of unsaturated fatty acids showed better oxidative stability during 14 days of cold storage, as shown by a low steady-state level of hydroperoxide values, than vacuum-packed chicken meat. Accordingly, the critical pressures of 400 MPa and 600 MPa for chicken breast and beef sirloin, respectively, were established. Volatiles released after opening of the meat bags or during storage of open meat bags, simulating consumer behaviour, were measured under conditions mimicking eating. Quantitative and olfactory analysis of pressurised meat gave a total of 46 flavour volatiles, mainly alcohols (11), aldehydes (15), and ketones (11), but all in low abundance after 14 days of storage. Overall, beef meat contained less volatiles and in lower abundance (factor of 5) compared to chicken meat. The most important odour active volatiles (GC-O) were well below the detection thresholds necessary to impart a perceivable off-flavour. Lipid oxidation was significantly accelerated during 24 h of cold storage in both cooked chicken and beef when exposed to oxygen, while the pressurised and oxygen-exposed chicken and beef meat remained stable. Pressure treatment of beef and chicken did not induce severe changes of their raw aroma profiles.     

Effects of high pressure level and holding time on properties of duck muscle gels containing 1% curdlan

The effect of high pressure processing (HPP) on properties of duck muscle gels (DMG) containing 1% curdlan was investigated. The application of > 300 MPa could result in the decrease of cooking loss of DMG in water binding capacity, the increase of L value and the decrease of a value and b value in color, the increase of hardness, springiness, cohesiveness and chewiness in textural parameters (P < 0.05), while the pressure-holding time had no obvious influence. Those experimental results could be attributed to the interactions among protein molecules and the interactions between protein molecules and curdlan molecules created or enhanced by HPP. Overall, the use of curdlan instead of fat and the application of HPP may provide a novel approach to achieve low-fat (< 6% fat) and low-salt (1% salt) DMG products with good properties and high yields.

Industrial relevance

To provide healthier meat foods like low-fat (< 6% fat) and low-salt (about 1% salt) duck meat products, the application of HPP might be of great interest for industrial manufacture and can yield the products bearing high water binding capacity and good textural properties.     

Kinetics of the formation of radicals in meat during high pressure processing

The kinetics of the formation of radicals in meat by high pressure processing (HPP) has been described for the first time. A threshold for the radicals to form at 400 MPa at 25 °C and at 500 MPa at 5 °C has been found. Above this threshold, an increased formation of radicals was observed with increasing pressure (400–800 MPa), temperature (5–40 °C) and time (0–60 min). The volume of activation (ΔV^#) was found to have the value −17 ml mol⁻¹. The energy of activation (E_a) was calculated to be 25–29 kJ mol⁻¹ within the pressure range (500–800 MPa) indicating high independence on the temperature at high pressures whereas the reaction was strongly dependent at atmospheric pressure (E_a = 181 kJ mol⁻¹). According to the effect of the processing conditions on the reaction rate, three groups of increasing order of radical formation were established: (1) 55 °C at 0.1 MPa, (2) 500 and 600 MPa at 25 °C and 65 °C at 0.1 MPa, and (3) 700 MPa at 25 °C and 75 °C at 0.1 MPa. The implication of the formation of radicals as initiators of lipid oxidation under HPP is discussed.     

Mechanical and functional properties of beef products obtained using microbial transglutaminase with treatments of pre-heating followed by cold binding

Beef proteins are considered non-setting proteins and usually gels obtained by adding of microbial transglutaminase are obtained by cooking directly the solubilized paste. The aim of this work was to determine the effect of pre-heating treatments on the mechanical properties of restructured beef gels treated with microbial transglutaminase (MTG). The effect of cooling (cold binding) the solubilized pastes after the pre-heating treatments was also studied. The restructured beef gels were obtained by adding 0.3% MTG or 0% MTG (control). Three pre-heating temperatures (40, 50 or 60 °C) for 30 or 60 min were studied, followed by heating at 90 °C for 15 min. Control samples without pre-heating were also prepared. Cold binding was studied by holding pre-heated gels at 4 °C for 12 h before heating at 90 °C for 15 min. Changes in mechanical properties (texture profile analysis and puncture test), color attributes, expressible water and cooking loss were determined. Results indicated that the better mechanical properties can be obtained by pre-heating beef pastes at 50 °C for 30 min with minimal effect on color, expressible water and cooking loss when 0.3% of MTG is added. It was concluded that there were no practical advantages by pre-heating the gels for 60 min. Cold binding did not improve the mechanical properties of beef gels.     

Evaluation of red bean protein [Vigna angularis] isolate on rheological properties of pork myofibrillar protein gels induced by microbial transglutaminase

The effects of 1% red bean protein isolate (RBPI) on the gel properties of myofibrillar protein (MP) in various levels of microbial transglutaminase (MTG: 0%, 0.1%, 0.5%, & 1%) were evaluated. The cooking yield (CY) of the MP gels decreased with increasing MTG level, while the addition of RBPI improved the CY of the MP gels. Gel strength (GS) was also improved when RBPI was incorporated into the MP gels containing higher than 0.5% of MTG. The addition of MTG and RBPI was slightly changed the endothermic peak temperatures. Scanning electron microscopy (SEM) showed that the three‐dimensional structure of MP with RBPI alone or in combined with MTG was compacted as compared to the control. Based on the results, RBPI could be functioned as a substrate for MTG (0.5–1.0%) and a water binder of meat protein gel mediated by MTG.     

Raman spectroscopy study of the structural effect of microbial transglutaminase on meat systems and its relationship with textural characteristics

Raman spectroscopy and texture analysis (TPA) studies were carried out to determine the effect of adding different levels of microbial transglutaminase (MTGase) to meat systems. This addition produced a significant (p < 0.05) increase in hardness, springiness and cohesiveness in the meat systems. Raman spectroscopy analysis revealed the occurrence of secondary structural changes in meat proteins due to MTGase. Modifications in the amide I (1650–1680 cm⁻¹) and amide III (1200–1300 cm⁻¹) regions indicated a significant (p < 0.05) decrease in α-helix content, accompanied by a significant (p < 0.05) increase in β-sheets and turns due to the addition of the enzyme to meat systems. Significant (p < 0.05) correlations were found between these secondary structural changes in meat proteins and the textural properties (hardness, adhesiveness, springiness and cohesiveness) of meat systems.     

Effect of sage and garlic on lipid oxidation in high-pressure processed chicken meat

Sage was found to protect minced chicken breast processed with high hydrostatic pressure up to 800 MPa for 10 min against lipid oxidation during subsequent chilled storage for 2 weeks. Garlic showed prooxidative effects especially at moderate high pressure around 300 MPa, an effect partly counteracted by simultaneous addition of sage. From the rate of lipid oxidation, measured as thiobarbituric acid reactive substances, the apparent volume of activation for pressure-induced lipid oxidation during subsequent chilled storage was estimated, which showed that the prooxidative effect of garlic and pressure-induced lipid oxidation were additive. Based on electron spin resonance (ESR) spectroscopy radical formation was measured in pressurized lipid and aqueous phases of minced chicken thighs, and a high radical scavenging capacity of sage in the lipid phase was identified as most important for the protective effect of sage.     

Conventional freezing plus high pressure-low temperature treatment: Physical properties, microbial quality and storage stability of beef meat

Meat high-hydrostatic pressure treatment causes severe decolouration, preventing its commercialisation due to consumer rejection. Novel procedures involving product freezing plus low-temperature pressure processing are here investigated. Room temperature (20 °C) pressurisation (650 MPa/10 min) and air blast freezing (−30 °C) are compared to air blast freezing plus high pressure at subzero temperature (−35 °C) in terms of drip loss, expressible moisture, shear force, colour, microbial quality and storage stability of fresh and salt-added beef samples (Longissimus dorsi muscle). The latter treatment induced solid water transitions among ice phases. Fresh beef high pressure treatment (650 MPa/20 °C/10 min) increased significantly expressible moisture while it decreased in pressurised (650 MPa/−35 °C/10 min) frozen beef. Salt addition reduced high pressure-induced water loss. Treatments studied did not change fresh or salt-added samples shear force. Frozen beef pressurised at low temperature showed L, a and b values after thawing close to fresh samples. However, these samples in frozen state, presented chromatic parameters similar to unfrozen beef pressurised at room temperature. Apparently, freezing protects meat against pressure colour deterioration, fresh colour being recovered after thawing. High pressure processing (20 °C or −35 °C) was very effective reducing aerobic total (2-log₁₀ cycles) and lactic acid bacteria counts (2.4-log₁₀ cycles), in fresh and salt-added samples. Frozen + pressurised beef stored at −18 °C during 45 days recovered its original colour after thawing, similarly to just-treated samples while their counts remain below detection limits during storage.     

Viscoelastic properties of high pressure and heat induced tofu gels

Tofu gels were rheologically examined to determine their storage or elastic (G′) and loss or viscous (G″) moduli as a function of frequency within their linear viscoelastic limits. The tofu gels were made using either glucono-δ-lactone (GDL) or calcium sulphate (CaSO₄·2H₂O), followed by either heat treatment (heated soymilk at ?97 °C prior to coagulation and subsequently held at 70 °C for 60 min, HT) or high pressure treatment (400 MPa at 20 °C for 10 min, HP). The overall moduli values of the GDL gels and CaSO₄·2H₂O gels of both physical treatments were similar, each gave frequency profiles expected for weak viscoelastic materials. However, although both temperature and high pressure treatments could be used to produce tofu gels, the final products were not the same. Pressure formed gels, despite having a higher overall “consistency” (increasing values of their moduli), had a proportionately higher contribution from the loss modulus (increased tan δ). Differences could also be observed using confocal scanning laser microscopy. While such treatment may give rise to differing systems/structures, with new or modified organoleptic properties, the more “open” structures obtained by pressure treatment may well cause processing difficulties if subsequent reworking or moulding is required.     

Quality considerations with high pressure processing of fresh and value added meat products

Pressure can be applied by high hydrostatic pressure, better known as high pressure processing (HPP), or by hydrodynamic pressure (HDP) in the form of shockwaves to alter quality parameters, such as shelf-life and texture of meat and meat products. The aim of this review is to give an overview of the use of pressure in the meat industry and to highlight its usage as a method to inactivate microorganisms but also a novel strategy to alter the structure and the quality parameters of meat and meat products. Benefits and possibilities of the technologies are presented, as well as how to overcome undesired product changes caused by HPP. The use of hydrodynamic shockwaves is briefly described and a promising newly developed industrial prototype for the generation of shockwaves by underwater explosion is presented.     

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.     

Gelation properties of chicken myofibrillar protein induced by transglutaminase crosslinking

Gelation properties of chicken myofibrillar protein isolate (MPI) and the effect of microbial transglutaminase (MTG) were studied using a dynamic oscillatory rheometer and a texture analyzer. Final heating temperature had a great impact on gel stiffness and the maximum gel stiffness was obtained at 95 °C. pH and ionic strength also influenced gel stiffness and the maximum gel stiffness was achieved at pH 6, 0.9 M NaCl; however, less stiff gels were formed in 0.6 and 1.2 M NaCl. In the MPI concentration range of ∼0.5-5%, a positive correlation was observed between gel stiffness or gel peak force and MPI concentration. When MTG was included at levels of ∼0 to 12-15 U, positive linear relations were found between gel stiffness or peak force and MTG levels. However, negative correlations for these parameters were observed at higher MTG concentrations. When MTG level was greater than 15 U, gel stiffness or peak force tended to decrease. The improvement in gel strength or gel peak force for the MPI with inclusion of MTG suggested that some ε (γ-glutamyl) lysine (G-L) crosslinking occurred among myofibrillar molecules. Thus, MTG is useful in improving gelation properties of heat-induced MPI gel and provides new opportunities to expand the utilization of low value meat in muscle foods.     

Use of microbial transglutaminase and nonmeat proteins to improve functional properties of low NaCl, phosphate-free patties made from channel catfish (Ictalurus punctatus) belly flap meat

ABSTRACT:  This study was aimed at developing value-added low sodium chloride (NaCl), phosphate-free restructured patties using minced channel catfish ( Ictalurus punctatus ) belly flap meat. The effect of microbial transglutaminase (MTGase) and nonmeat proteins (isolated soy protein, ISP, and whey protein concentrate, WPC; 1.7%, respectively) alone and in combination were evaluated to improve cooking yield and textural properties in patties with reduced NaCl and no phosphate. The concentration effect of MTGase (0.05% to 0.7%) was also studied. The addition of MTGase increased textural properties such as binding strength, hardness, cohesiveness, chewiness, and springiness, but decreased cooking yield of the patties ( P < 0.05). Isolated soy protein increased cooking yield ( P < 0.05), but did not affect textural properties. Inclusion of WPC did not increase cooking yield or impact textural properties of patties. The combination of MTGase and ISP significantly increased both the cooking yield and textural properties of patties. As the concentration of MTGase increased at constant ISP, the textural properties of cooked patties significantly increased, but cooking yield decreased ( P < 0.05). In conclusion, we suggest that the combination of 0.05% to 0.1% of MTGase with 1.7% ISP is optimal for development of a low NaCl, phosphate-free patty using minced catfish belly flap meat.