High pressure induced changes in beef muscle proteome: Correlation with quality parameters

The relationship between pressure induced changes on individual proteins and selected quality parameters in bovine longissimus thoracis et lumborum (LTL) muscle was studied. Pressures ranging from 200 to 600 MPa at 20 °C were used. High pressure processing (HPP) at pressures above 200 MPa induced strong modifications of protein solubility, meat colour and water holding capacity (WHC). The protein profiles of non-treated and pressure treated meat were observed using two dimensional electrophoresis. Proteins showing significant differences in abundance among treatments were identified by mass spectrometry. Pressure levels above 200 MPa strongly modified bovine LTL proteome with main effects being insolubilisation of sarcoplasmic proteins and solubilisation of myofibrillar proteins. Sarcoplasmic proteins were more susceptible to HPP effects than myofibrillar. Individual protein changes were significantly correlated with protein solubility, L*, b* and WHC, providing further insights into the mechanistic processes underlying HPP influence on quality and providing the basis for the future development of protein markers to assess the quality of processed meats.     

Colour and sarcoplasmic protein evaluation of pork following water bath and ohmic cooking

The objective of this study was to investigate the effects of ohmic (OH) and waterbath (WB) cooking on colour attributes and sarcoplasmic changes of porcine longissimus dorsi muscle at the same endpoint temperatures (EPTs; range 10 °C–80 °C). The OH treatment was carried out at 10 V cm^− 1, and the WB temperature at 85 °C. The colour parameters, deoxymyoglobin% (DeoMb) and metmyoglobin% (MetMb) of the OH-cooked meat were significantly lower (P < 0.05) than those obtained by WB-cooking at the same EPTs (range 60 °C–80 °C). SDS-PAGE analysis showed that the meat treated with WB-cooking had a lower sarcoplasmic protein solubility (5.97 mg/g vs.14.89 mg/g, P < 0.05) and fainter protein bands than that of OH-cooking thus, indicating paler colour, and lower water-holding capacity especially in WB-cooked meat at EPTs above 40 °C. Strong correlations among lightness, browness, metmyoglobin% and soluble proteins were observed in meat following OH-cooking.     

Effect of high pressure processing and cooking treatment on the quality of Atlantic salmon

The effect of high pressure treatment (HPP) (150 MPa and 300 MPa for 15 min) and cooking on quality of Atlantic salmon based on microbial activity, lipid oxidation, fatty acid profile, colour and texture during 6 days of storage was studied. High pressure and cooking significantly (p < 0.05) reduced microbial growth. The 300 MPa treatment and cooking showed higher L∗ and b∗ values but lower a∗ values for dark muscle compared to control and samples treated at 150 MPa. An increase in pressure resulted in an increase in hardness, gumminess and chewiness parameters, and a decrease in adhesiveness compared to control and cooked samples. Whereas cooking and 150 MPa led to similar oxidation development as control in dark muscle, the 300 MPa treatment effectively reduced the samples susceptibility to oxidation. Fatty acid profile of cooked Atlantic salmon dark muscle showed significantly (p < 0.05) lower amounts of total saturated, n−3 Polyunsaturated fatty acids (PUFA) and n−6 PUFA and significantly (p < 0.05) higher amounts of monoenes than HPP treated samples during the entire storage period. However, the most important finding of this study was that there was no significant (p > 0.05) difference between control and HPP treated samples in terms of total saturated, monoenes, n−3 PUFA and n−6 PUFA fatty acid profile. This demonstrates that HPP is a very mild process in terms of its effect on fatty acids.     

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.     

Monitoring the effects of high pressure processing and temperature on selected beef quality attributes

The combined effects of high pressure processing (HPP) and temperature on meat quality attributes were assessed in bovine M. pectoralis profundus, with particular focus on lipid oxidation and fatty acid composition. Beef samples were pressurised at 200, 300 and 400 MPa at two different temperatures 20 °C and 40 °C. Both pressure and temperature regimes had significant effects on colour, cook loss and lipid oxidation. Pressurisation at 200 MPa had a lower impact on colour parameters than higher pressurisation levels. Cook loss also increased when higher levels of pressure were applied. Across all pressure conditions, lower cook loss was observed at 40 °C compared to 20 °C. An increase in TBARS values was observed at the higher pressure levels (300, 400 MPa). While some alterations of individual fatty acids were observed, high pressure had no effect on polyunsaturated/saturated fatty acid (PUFA/SFA) or omega 6/omega 3 (n6/n3) ratio. The temperature at which HPP was applied had a significant effect on the sum of saturated (SFA), monounsaturated (MONO) and polyunsaturated (PUFA) fatty acids. HPP at 40 °C showed higher SFA and PUFA and lower MONO compared to HPP at 20 °C. These results show that high pressure at low or moderate temperatures improves the microbiological quality of the meat with minimal affects on meat quality.     

Effects of supercritical carbon dioxide treatment for sterilization purpose on meat quality of porcine longissimus dorsi muscle

The objective of this study was to investigate the effect of supercritical carbon dioxide (SC-CO₂) treatment for the sterilization purpose on meat quality and protein denaturation of the porcine longissimus dorsi muscle. The conditions of SC-CO₂ treatment were 7.4 and 15.2 MPa at 31.1 °C for 10 min. SC-CO₂ treatment had no effect on muscle pH, tenderness, and water-holding capacity (WHC). However, the samples treated at 7.4 MPa had a higher lightness value (52.97 vs. 46.94, P<0.001) and a more pronounced extent of sarcoplasmic protein denaturation (73.80 vs. 80.73, P<0.01) than the control samples. These results suggest that the paler color of samples treated with SC-CO₂ was associated with the sarcoplasmic protein denaturation, and the major denaturated proteins were determined to be phosphorylase b (PH), creatine kinase (CK), triosephophate isomerase (TPI), and one unknown protein. On the other hand, other quality traits were generally unaffected by the SC-CO₂ treatments at 7.4 or 15.2 MPa.     

High-pressure processing and water-holding capacity of fresh and cold-smoked salmon (Salmo salar)

The influence of high pressure on the water-holding capacity (WHC) of fresh and cold-smoked salmon (CSS) was investigated up to a pressure level of 200 MPa at room temperature for 10- and 20-min periods. Changes in moisture content and WHC were determined by two methods, namely filter paper and spin-spin relaxation proton nuclear magnetic resonance. Both pressure (p<0.05) and process time (p<0.05) had significant effects on the moisture content of CSS, but not on fresh Atlantic salmon. Fresh salmon had less WHC than smoked salmon and a pressure of 150 MPa for 10 min caused a 2% increase in WHC of smoked salmon (p<0.001). The spin-spin proton relaxation (T₂) values were heavily affected by high pressure in both the samples, with substantial effects seen in CSS. At 150 MPa, both fresh and smoked fish behaved differently with respect to T₂ values compared with other pressure levels used.     

Evaluation of the effects of selected plant-derived nutraceuticals on the quality and shelf-life stability of raw and cooked pork sausages

The effect of lutein (200 μg/g meat), sesamol (250 μg/g meat), ellagic acid (300 μg/g meat) and olive leaf extract (200 μg/g meat) on total viable counts (TVC), pH, water holding capacity (WHC), cooking loss, lipid oxidation (thiobarbituric acid-reactive substances, TBARs), colour stability, texture and sensory evaluation of fresh and cooked pork sausages stored in aerobic or modified atmosphere packs (MAP) was investigated. Addition of sesamol, ellagic acid and olive leaf extract reduced (P < 0.001) lipid oxidation in all packaged raw and cooked pork sausages. Antioxidant potency followed the order: sesamol 250 > ellagic acid 300 > olive leaf extract 200 > lutein 200 for both raw and cooked pork sausages. Addition of sesamol increased (P < 0.001) WHC on days 2 and 12 of MAP storage. Meat addition of lutein, sesamol, ellagic acid and olive leaf extract had no detrimental effect on pH, cooking losses, TVCs, tenderness, juiciness, texture or product flavour. Lutein, sesamol, ellagic acid and olive leaf extract were effective as natural functional ingredients in suppressing lipid oxidation and have the potential to be incorporated into functional raw and cooked pork sausages.     

Effect of high-pressure processing on Listeria spp. and on the textural and microstructural properties of cold smoked salmon

Investigation of the effect of high-pressure processing (HPP) at very short time on the inactivation of Listeria innocua was conducted as well as the effect on texture and microstructure. Lipid oxidation, colour and background bacterial flora were studied as well. HPP at 700-900 MPa for 10 s increased the inactivation of L. innocua in cold smoked salmon from 4500 cfu/g to nondetectable level (<0.3 cfu/g). L. innocua was more sensitive to HPP than the background flora tested. The product presented good microbiological quality and there was no indication of lipid oxidation. The effect of HPP on the redness of the product was not observed, however immediate effect on the lightness was noticed and the salmon becomes lighter in colour as a function of both time and pressure. The effects on the microstructure increased with both time and pressure and were most significant at 900 MPa and 60 s. The effect on microstructure coincides with the reduction of the bacteria. The knowledge from this study provides information for the industry on the development of HPP at 400-900 MPa with short pressure time of less than 60 s.     

Effect of high pressure processing on the gel properties of salt-soluble meat protein containing CaCl2 and κ-carrageenan

The effects of high pressure processing (HPP) on the water-binding capacity and texture profile (TPA) of salt-soluble meat protein (SSMP) containing 0.2% CaCl₂ and 0.6% κ-carrageenan (SSMP-CK) gels were investigated. The results showed that 300–400 MPa improved water-binding capacity and decreased TPA parameters of SSMP-CK gels (P < 0.05), while 100 MPa could increase hardness and chewiness of the gels. The thermal transition temperature peak for the myosin head (T_peak1) of SSMP disappeared on addition of CaCl₂ and κ-carrageenan. 300 MPa produced a new peak, and caused a shift of the NH-stretching left peak and amide I and the disappearance of NH-stretching right peak. The destruction of network structure and the weakening of molecular interaction within the pressurized gels could result in the decrease of TPA parameters. Thus gelling properties could be modified by HPP, κ-carrageenan and Ca^2 +. It is of interest to develop low-fat and sodium-reduced meat products.     

Properties of a protein-based film from round scad (Decapterus maruadsi) as affected by muscle types and washing

The effects of muscle types and washing on the properties of a protein-based film from round scad (Decapterus maruadsi) mince were investigated. Washing resulted in an increase in the protein content with a coincidental decrease in the fat content of mince, especially from whole muscle and dark muscle. Among all types of muscle (ordinary, dark and whole muscle), the ordinary muscle rendered the film with the highest tensile strength (TS) (p < 0.05). TS of films from washed mince was greater than that of films prepared from unwashed mince for the same type of muscle used (p < 0.05). Nevertheless, the water vapour permeability (WVP) of films from unwashed mince was higher than that of films prepared from washed mince (p < 0.05). Films from washed mince had higher solubility but lower protein solubility than those from unwashed mince (p < 0.05). Regardless of washing, films from ordinary muscle showed the highest L^∗-value (p < 0.05). However, films prepared from dark muscle were more yellowish than those prepared from other muscles, as evidenced by the greater b^∗-value. Films from round scad mince and washed mince had excellent barrier properties to UV light at the wavelength of 200–280 nm. Generally, films from round scad mince had a lower preventive effect on visible light transmission than had those from unwashed mince. Among films from all muscles, those prepared from dark muscle exhibited the highest barrier to visible light transmission (p < 0.05). Therefore, the properties of films from round scad meat were governed by muscle type as well as by washing.     

A proposed mechanism of tenderising post-rigor beef using high pressure–heat treatment

Tenderness of beef M. Sternomandibularis was tough when cooked from both raw, and when previously heated (60 °C, 20 min), whereas a significant improvement in tenderness was achieved when pressure–heat (P–H) treated muscle (200 MPa, 60 °C, 20 min) was cooked. In order to determine the mechanism for this improvement, connective tissue, myofibrillar and sarcoplasmic proteins, were separated into three fractions and studied with regard to their solubilisation, denaturation and aggregation, degradation and strengthening of protein structures for the three treatments (raw, heated and H–P treated). Measurements included DSC, SDS–PAGE, surface hydrophobicity, and the appearance, length and width of myofibres (light microscopy). For the connective tissue fraction, heat solubility was determined.     

A note on the relationships between cured-cooked and dry-cured ham processing yields

Right and left hams from 353 pigs slaughtered at around 100 kg body weight were processed into cured-cooked hams and dry-cured hams, respectively. Weights and yields at various stages of each process, carcass lean content and fresh meat quality traits were registered. Technological yield of cured-cooked processing (saleable cooked ham weight/defatted–deboned fresh ham weight) was more closely correlated to ultimate pH (r = 0.51, p < 0.001) than to carcass leanness (r = −0.13, p < 0.05) whereas the reverse situation – r = 0.15 (p < 0.01) and r = −0.62 (p < 0.001), respectively – was found for technological yield of dry-cured processing (saleable dry ham weight/trimmed fresh ham weight). The correlation between the two technological yields was significantly positive but of fairly moderate magnitude (r = 0.36). The correlation between the overall yields (saleable processed ham weight/entire fresh ham weight) of the two processes revealed to be very close to zero (r = −0.01).     

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.     

Physicochemical and functional changes in jumbo squid (Dosidicus gigas) mantle muscle during ice storage

Physicochemical and functional changes of jumbo squid (Dosidicus gigas) mantle muscle stored in ice for 15 days were evaluated. Proximate analysis, pH, protein solubility (PS) and SDS-PAGE profile changes were monitored for muscle proteins, while texture profile analysis (TPA) (gel strength, elasticity and cohesiveness), water holding capacity (WHC) and colour changes were monitored for gels produced from this muscle. Fresh muscle chemical composition varied according to fishing season and/or physiological status presented by specimens. pH and PS were stable (p ? 0.05) throughout the study with a slight tendency to decrease towards the end of study. SDS-PAGE revealed no drastic changes in proteins influencing gelation (i.e., myosin). TPA and WHC of gels decreased towards the end of experiment; however, due to sampling variability, no significant differences (p ? 0.05) were found over storage time. Changes in gel colour were observed with hue angle decreasing towards yellow hues. Improved post-capture management of mantle muscle preserved its integrity and functionality for up to two weeks.     

CO2 stunning procedure on Manchego light lambs: Effect on meat quality

This study examined the effect of different gas stunning methods (concentration of CO₂/time of exposure (G1: 80%90s; G2: 90%90s; G3: 90%60s; G4: 80%60s) on the initial meat quality of Manchego breed light lambs (25 kg live weight) and at 7 days post-mortem, assessed by pH, colour coordinates, water holding capacity (WHC), cooking loss (CL), drip loss (DL) shear force (SF) and lipid oxidation. An electrically stunned control group (G5) was used. Stunning method had a significant effect on pH values (P < 0.001) as well as on pH decline (P < 0.01). The lowest pH was found at 24 h post-slaughter in G1 and the highest one on G5. The greatest drop in pH (pH₀–pH₂₄) was found in G1 and G5 while the smallest in G3. In general values of colour coordinates, WHC and DL were similar in all groups. Stunning method affected CL (P < 0.001) at 7 days post-slaughter, with the lowest values being found in G1. Significant differences among groups were found (P < 0.05) in SF values at both post-mortem times, with less tender meat in groups stunned with 80% CO₂, especially in G1. A significant effect (P < 0.001) due to the type of stunning was found at 24 h on lipid oxidation, with the highest value in G5. After ageing this parameter was lowest (P < 0.05) in G1 and G4.     

Effect of high pressure processing on rheological and structural properties of milk–gelatin mixtures

There is an increasing demand to tailor the functional properties of mixed biopolymer systems that find application in dairy food products. The effect of static high pressure processing (HPP), up to 600 MPa for 15 min at room temperature, on milk–gelatin mixtures with different solid concentrations (5%, 10%, 15% and 20% w/w milk solid and 0.6% w/w gelatin) was investigated. The viscosity remarkably increased in mixtures prepared with high milk solid concentration (15% and 20% w/w) following HPP at 300 MPa, whereas HPP at 600 MPa caused a decline in viscosity. This was due to ruptured aggregates and phase separation as confirmed by confocal laser scanning microscopy. Molecular bonding of the milk–gelatin mixtures due to HPP was shown by Fourier-transform infrared spectra, particularly within the regions of 1610–1690 and 1480–1575 cm⁻¹, which reflect the vibrational bands of amide I and amide II, respectively.     

High-Pressure Pretreatment to Improve the Water Retention of Sodium-Reduced Frozen Chicken Breast Gels with Two Organic Anion Types of Potassium Salts

The effect of high-pressure pretreatment (HPP, 100–300 MPa) before heating on the water holding capacity (WHC) and cooking loss (CL) of sodium-reduced (1.35% NaCl) frozen chicken breast gels with the organic anion types potassium lactate (KL-gel) and potassium citrate (KC-gel) was investigated. The results showed that 100–300 MPa could significantly decrease the CL of both gels, and 200 MPa increased the WHC of the KC-gel (P?<?0.05). HPP could decrease the storage modulus (G′) of meat batters, increase the thermal stability of their proteins, facilitate gelation with a dense and uniform microstructure, and immobilize free water, thus improving the gel’s water retention. The water retention of the pressurized sodium-reduced gel varied with the organic anion types of salts. The water retention was better with pressurized KC-gel than with KL-gel, resulting from higher pH and thermal stability of the batters. These results indicate that proper HPP could improve the water retention of sodium-reduced meat gels with organic potassium salts, thus increasing the economic benefit and properties of sodium-reduced products from frozen meat.     

Quality changes in oyster (Crassostrea belcheri) during frozen storage as affected by freezing and antioxidant

Changes in physical, chemical, microbiological and sensory qualities of individual quick frozen (IQF) and contact plate frozen (CPF) oyster (Crassostrea belcheri) meat, treated and untreated with butylated hydroxyanisole (0.02% BHA suspension) during storage at −20 °C for 12 months were investigated. Increase in expressible drip of IQF oyster was slower than that of CPF oyster, due to the fact that quick freezing (IQF) resulted in less tissue damage than slow freezing (CPF). Neither freezing method nor antioxidant treatment caused significant changes in chemical qualities, i.e., pH, moisture, crude protein, crude fat and total volatile basic nitrogen (TVB-N), nor in microbiological qualities, i.e., total viable count (TVC), psychrotrophic bacteria, Escherichia coli and Vibrio parahaemolyticus. During frozen storage, TVC and psychrotrophic bacteria of both BHA-treated and untreated CPF oyster decreased with storage time increases (p < 0.05) at a slower rate than in IQF oyster. Antioxidant treatment could minimise sensory quality changes, especially the colour of frozen oyster during storage.