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     

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.     

高压和食盐对鸡肉肠品质特性的影响

在不同压强条件（0.1、200、400 MPa）下对不同食盐添加量（质量分数0%、1%、2%）的生鸡肉肠加热（60 ℃）处理30 min,测定处理后鸡肉肠的持水力、水分分布、质构特性和微观结构,分析高压和食盐对鸡肉肠热诱导凝胶特性的影响。结果发现：常压下,减少食盐添加量会降低鸡肉肠的保水性和质构特性,但高压处理能降低食盐对鸡肉肠的影响。相比常压组,200 MPa高压处理能显著提高产品的保水性和质构特性（P＜0.05）,而400 MPa的高压处理则显著降低产品的保水性和质构特性（P＜0.05）。高压能促进肉糜中的肌纤维分解,使不易流动水的比例升高,自由水比例下降;200 MPa下能形成致密的凝胶网络,而400 MPa则阻碍凝胶网络的形成。高压结合加热处理可用于提高低盐鸡肉肠的品质特性。     

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.     

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 pressure and holding time on colour,protein and lipid oxidation of sliced dry-cured Iberian ham and loin during refrigerated storage

The effect of high pressure (HP) treatments (200 MPa 15 min, 200 MPa 30 min, 300 MPa 15 min, 300 MPa 30 min) on colour, lipid and protein oxidation in sliced vacuum-packed dry-cured Iberian ham and loin during refrigerated storage (90 days, + 4 °C) was evaluated. Pressure level and holding time increased the extent of lipid oxidation in both products. Dry-cured ham showed a higher susceptibility to lipid oxidation than dry-cured loin since HP treatment increased TBA-RS values in dry-cured ham samples while HP treatment decreased TBA-RS values in dry-cured loin samples. However, HP treatment did not affect protein oxidation in both meat products. On the other hand, HP treatment affected instrumental colour since non-pressurized dry-cured meat products showed higher redness than pressurized ones. Regarding changes under storage, after 90 days of refrigerated storage lipid and protein oxidation increased while redness decreased in both HP treated and non-treated dry-cured meat products. Changes induced by HP were only noticeable after HP treatment, as storage reduced the initial differences between HP treated and non-treated samples. Therefore, the lack of differences in long stored dry-cured ham and loin HP treated and non-treated indicates that the application of HP (200–300 MPa/15–30 min) could not affect the quality of dry-cured meat products.Industrial relevanceDry-cured meat products are the meat-based products with the highest sensory quality in Spain and have a high projection in exterior markets. High pressure processing is effective in controlling pathogen and spoilage microorganisms in meat and meat products although it can promote color and oxidation changes that modify sensory characteristics. The study aimed the evaluation of pressure and holding time on color changes and protein and lipid oxidation at vacuum packed slices of Iberian dry-cured ham and loin during subsequent extended chilled storage. High pressure treatment of dry-cured Iberian ham and loin induce changes after treatment although initial differences are not maintained along refrigerated storage.     

低场核磁共振研究高压处理对乳化肠特性的影响

以低温乳化肠为材料,对0.1 ～ 400 MPa 压力处理组肉糜进行扫描电镜观察和低场核磁共振检测,评估加热后的感官特性,并进行相关性分析,从显微结构和水分子弛豫特性变化角度揭示高压处理对乳化肠感官特性改善的原因。结果表明：与对照组相比,压力从100 MPa 增大到200 MPa,感官特性得分增加,而200 MPa 到400 MPa得分减小（P ＜ 0.05）;扫描电镜结果显示各组肉糜显微结构存在明显差异;T2 弛豫结果显示,实验组T21 峰面积大于对照组而T22 峰面积小于对照组（P ＜ 0.05）,T21 弛豫时间在压力从100 MPa 增大到200 MPa 过程中升高,而在200 MPa 到400 MPa 降低（P ＜ 0.05）;相关性分析表明,感官特性各指标与T21 弛豫时间及其峰面积正相关,与T22 峰面积负相关（P ＜ 0.05）。因此,高压处理使自由水部分转化为不易流动水,并影响不易流动水与肉糜蛋白的结合程度,而转化比例和结合程度的强弱又会显著影响肉糜微结构及其加热后的感官特性。     

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.     

Effects of high pressure processing on protein fractions of blue crab (Callinectes sapidus) meat

The studies about the effect of high pressure processing (HPP) on the myofibrillar proteins of crab meat are scarce in the literature. The aim of this study is to evaluate the effect of high pressure processing (HPP) at 100, 300 and 600 MPa (10 °C/5 min) on the muscular protein fractions of blue crab meat (Callinectes sapidus) and compares the effect of high pressure treatments and the thermal cooking process on the yielding of crab meat. Differential scanning calorimetry analysis of raw crab meat showed two peaks at 48.18 and 76.76 °C corresponding to myosin and actin denaturation. The increasing in the pressure level resulted in a decrease in denaturation enthalpy of both proteins. Data from Fourier transform infrared spectroscopy indicated changes in the secondary protein structures in which a reduction in α-helix and an increase in β-turn were observed as a result of denaturation induced by HPP. Electrophoresis analysis (SDS-PAGE) showed myofibrillar protein denaturation as the pressure level increased. The HPP at 100 and 300 MPa resulted in a significant increase in the yielding of meat extracted when compared to the thermal treatment (90 °C/20 min). Higher sensory scores were obtained in 300 and 600 MPa suggesting higher acceptance. Results suggest the feasibility of applying HPP as an alternative to the thermal treatment to process crab meat.Industrial relevanceHigh pressure processing (HPP) technology has been successfully applied to several seafood products. However, it is important to study the effect of HPP on the food components, mainly proteins in the crab meat to optimize the processing parameters to get high-quality products. In the present study, the benefit of using HPP as an alternative to the commercial thermal processing for extraction of crab meat has been confirmed. Applying 600 MPa (10 °C/5 min) to the whole blue crab resulted in a higher yield of extracted crab meat compared with the other treatments. However, using a range of 100–300 MPa (10 °C/5 min) also increases the yielding of extracted crab meat when compared to the thermal process, and moreover, the extraction procedure is faster. The quality and the functional properties of the crab meat with fresh appearance is preserved after the treatment at 100 MPa. These results could promote subsequent applications of pressurized crab meat in the crab industry, especially with the HPP treatments in a range between 100 and 300 MPa.     

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.     

Effects of high‐pressure homogenisation on physicochemical characteristics of partially skimmed milk

The changes in partially skimmed milk (0.5% fat) physicochemical properties and proteins after high‐pressure homogenisation (HPH) at 100, 200 and 300 MPa were investigated. Processing parameters and changes in pH, ethanol precipitation stability, lightness, whey protein denaturation, hydrophobicity and viscosity were evaluated. No significant differences were found between milk pH and nonprotein nitrogen content before and after HPH. Ethanol stability, lightness and hydrophobicity increased when pressure was increased from 100 MPa to 300 MPa. Whey protein denaturation, evaluated through noncasein nitrogen, occurred only at 200 to 300 MPa, and viscosity increased just at 300 MPa. Therefore, HPH changed some milk physicochemical characteristics, mainly those related to protein content. These results highlight that HPH processing is a promising technology to improve partially skimmed milk mouth feel being suitable for dairy products manufacturing.     

Combination of high pressure and heat on the gelation of chicken myofibrillar proteins

The effects of combinations of high pressure and heat on chicken myofibrillar gels were investigated. High pressure was either applied simultaneously with heating (heating under pressure, HUP), before heating (PBH) or no high pressure with heat-only (HT). PBH treatment induced many similar properties in gels as did by HT treatment, except that PBH treatment promoted secondary structure transformation and formed more covalent bonds. HUP treatment resulted in less heat denaturation of the protein, induced fewer hydrophobic interactions and covalent bonds, hindered secondary and tertiary structural transformation, and formed a gel with a more porous microstructure. The gels induced by HUP treatment had softer texture and higher water holding capacity than gels induced by PBH or HT treatments. These findings suggest that high pressure with HUP treatment changes gel properties by resisting the heat-induced denaturation and gelation of myofibrillar proteins, while high pressure with PBH treatment alters gel properties by promoting denaturation of myofibrillar proteins.Industrial relevanceThe main constituents in meat are myofibrillar proteins, which are responsible for the functional properties of processed meat products. The gelation of myofibrillar proteins differs according to the sequence in which pressure/temperature combinations are applied. The pressure-modified protein interactions should be considered when adopting high pressure in meat product processing since the microstructure of the meat gel is affected by pressure, which would further affect water holding capacity and textural properties. HUP treatment showed its advantages in forming a fine microstructure and improving water-holding capacity.     

Influence of Xanthan Gum on the Structural Characteristics of Myofibrillar Proteins Treated by High Pressure

The effects of xanthan gum on the structural modifications of myofibrillar proteins (0.3 M NaCl, pH 6) induced by high pressure (200, 400, and 600 MPa, 6 min) were investigated. The changes in the secondary and tertiary structures of myofibrillar proteins were analyzed by circular dichroism. The protein denaturation was also evaluated by differential scanning calorimetry. Likewise, the protein surface hydrophobicity and the solubility of myofibrillar proteins were measured. High pressure (600 MPa) induced the loss of α‐helix structures and an increase of β‐sheet structures. However, the presence of xanthan gum hindered the former mechanism of protein denaturation by high pressure. In fact, changes in the secondary (600 MPa) and the tertiary structure fingerprint of high‐pressure‐treated myofibrillar proteins (400 to 600 MPa) were observed in the presence of xanthan gum. These modifications were confirmed by the thermal analysis, the thermal transitions of high‐pressure (400 to 600 MPa)‐treated myofibrillar proteins were modified in systems containing xanthan gum. As consequence, the high‐pressure‐treated myofibrillar proteins with xanthan gum showed increased solubility from 400 MPa, in contrast to high‐pressure treatment (600 MPa) without xanthan gum. Moreover, the surface hydrophobicity of high‐pressure‐treated myofibrillar proteins was enhanced in the presence of xanthan gum. These effects could be due to the unfolding of myofibrillar proteins at high‐pressure levels, which exposed sites that most likely interacted with the anionic polysaccharide. This study suggests that the role of food additives could be considered for the development of meat products produced by high‐pressure processing.     

Tenderness improvement of reduced-fat and reduced-salt meat gels as affected by high pressure treating time

This study investigated the effect of high-pressure treating time (HPTT) on the tenderness of reduced-fat reduced-salt (RFRS) meat gels. The result of shear force value showed that the RFRS meat gels exhibited excellent tenderness treated with 200 MPa for 3 min. The mechanism of tenderness enhancement was revealed from the perspective of water migration characteristics in meat batters. After HPP, the characteristics of water molecules in meat batters were investigated using low-field nuclear magnetic resonance (LF-NMR) T₂ relaxometry. The datas of T₂ relaxation time and peak area indicated the free water changed into immobilized water significantly. The result of principal components analysis showed that the sample treated with a proper HPPT (3 min) was significantly different from the others. The tenderness of RFRS meat gel products was improved with the application of 200 MPa, especially treated with 3 min. The improvement of tenderness could be ascribed to the increase of immobilized water. The possible increase of the diameter in three-dimensional gel network might lead to more water molecules entrapped.     

Effect of high pressure processing on the physicochemical and sensorial properties of scallop (Mizuhopecten yessoensis) during iced storage

Scallops are the third largest aquaculture mollusks product, while they are highly perishable during storage. The main purpose of the present study was to evaluate the effect of high pressure processing (HPP) on physicochemical and sensorial properties of scallop (Mizuhopecten yessoensis) during refrigeration storage. The scallop adductor muscle was treated with different pressures (200, 300, 400 and 500 MPa, 5 min) and iced storage for 28 days. Results showed that HPP delayed microbial growth as pressure increased. HPP (≥400 MPa) resulted in myosin and actin denaturation, increased hardness, whiteness, pH and promoted water migration. However, preliminary sensory analysis showed no significant difference between pressure-treated and control adductor muscles in appearance, odour, texture and overall acceptability after cooking. In addition, pressure-treated adductor muscles (≥300 MPa) remained edible after 28 days of storage. Overall, these results can provide basic knowledge for the storage of pressure-treated scallop meat.     

Effect of high-pressure treatment on the quality of prepared chicken breast

In this study, the effect of high-pressure processing (HPP) on the physico-chemical properties and microstructure of prepared chicken breast meat products was investigated. The result showed that the pH and TBARS values of the prepared chicken breast gradually increased, while the total volatile basic nitrogen value constantly decreased with the increase of pressure (0.1–500 MPa). In addition, the colour attributes (L* and a* values) and texture indexes (hardness and chewiness) significantly improved as the pressure increased. The results of low-field nuclear magnetic resonance demonstrated that the peak area of immobilised water (T₂₂) first enhanced and then declined with the increase of pressure, reaching the maximum value at 200 MPa. Moreover, the integrity of microstructure and protein secondary structure of prepared chicken breast were also disrupted. These findings could serve as a theoretical basis for a better application of HPP in prepared chicken breast meat products.     

Use of high pressure to reduce cook loss and improve texture of low-salt beef sausage batters

Methods were investigated to reduce the salt content of beef-containing smallgoods as high-salt intake has been identified as a public health risk for most individuals. Raw meat batters were manufactured from retail beef mince (4–7% fat) using various NaCl concentrations (0–2%), and were packed into casings and subjected to high pressure processing (up to 400 MPa for 2 min at 10 °C). Following pressure treatment, samples were cooked to an internal temperature of 72 °C and cooled. Cooked products were assessed for cooking loss, colour and physical consistency by texture profile analysis. Flavour and overall acceptability were assessed by sensory panels. High pressure processing (HPP) was found to produce a dramatic improvement in the moisture retention of the cooked products. Control (unpressurised) sausages containing 2% NaCl had a similar cook loss (9.3%) to pressure-treated sausages containing just 1% NaCl, whereas unpressurised samples with 1% NaCl had a cook loss of 24.9%. The hardness and gumminess of pressure-treated samples was higher compared to untreated samples, at all salt concentrations. The greatest differences in texture with pressure treatment were seen in the 1% NaCl samples. Pressure treatment generally caused no changes in the colour of either the raw or cooked product; however there was a slight increase in “whiteness” with pressure treatment. Sensory panels reported a greater acceptability in both appearance and texture of pressure-treated sausages of lower salt content compared with non-pressure-treated samples. Examination of extracted proteins using SDS-PAGE and of muscle proteins by thermal analysis indicated that pressure contributed to enhanced binding through protein solubilisation and gelation through partial protein unfolding. The application of high pressure to beef sausages with low-salt content resulted in reduced cooking losses and improved texture.

Industrial relevance

Enhanced meat binding through extraction of salt-soluble proteins is an essential step in the formulation of meat products such as sausages and emulsion-type products. The ability to reduce salt and achieve high binding and water retention through use of HPP is important in being able to produce healthier foods.     

High‐pressure processing‐induced conformational changes during heating affect water holding capacity of myosin gel

This study aimed to investigate the effects of high‐pressure processing (HPP) (0.1‐400 MPa for 9 min) on the water holding capacity (WHC) of heat‐induced rabbit myosin gel and structural changes during thermal treatment (25–75 °C). HPP at 100 MPa significantly increased the WHC (P < 0.05) and formed more regular and homogeneous three‐dimensional network. Myosin tails at 100 MPa unfolded completely during the thermal treatment, which was beneficial to form a high WHC gel network. However, myosin pressurised at 200 MPa and above formed a weak gel. Their heads were already aggregated before heating, preventing from subsequent thermal denaturation and aggregation. With the temperature increasing, unfolding of myosin tails was not sufficient for a filamentous network formation. These results suggested that HPP could modify the myosin structure and affect the gel formation during heating. The 100 MPa was the optimum pressure level for the WHC of rabbit myosin gel.     

DSC study on the influence of meat source, salt and fat levels, and processing parameters on batters pressurisation

 Hydrostatic high-pressure/temperature treatments were conducted at low (10 °C) and high temperatures (60, 70, and 80°C) on different types of meat batters. Pressure-induced effects on proteins were intensified by sodium chloride molarity at low and high temperatures. Treatments at 10°C under pressurisation yielded net thermal destabilisation effects on meat proteins pertaining either to muscle or batter systems. Heating at usual cooking temperature of 70°C under pressure yielded net stabilising effects on meat batter proteins. Overheating at 80°C was needed for entire protein denaturation. Pork and chicken meats were very similar in behaviour but chicken batters exhibited relatively higher thermal- and pressure-induced protein denaturation. Both kinds of physical destabilisation/stabilisation of proteins by pressure-induced effects increased with pressure level. Received: 30 December 1999 / Revised version: 14 February 2000     

Quality changes during the frozen storage of sea bass (Dicentrarchus labrax) muscle after pressure shift freezing and pressure assisted thawing

Quality of frozen sea bass muscle stored (1, 3 and 5 months) at two levels of temperature (−15 and −25 °C) after a pressure shift freezing process (200 MPa) — PSF — and/or a pressure assisted thawing process (200 MPa) — PAT — was evaluated in comparison with samples frozen and thawed using conventional methods (air-blast AF and AT, respectively). Frozen storage of high-pressure treated samples did not significantly affect initial quality of frozen muscle. Thus, parameters related to protein denaturation and extractability, water holding capacity and color presented similar values than those obtained for not stored samples. In addition, the improvement of the microstructure achieved by PSF application remains unchanged during frozen storage. On the other hand, conventional treated samples experienced significant changes during frozen storage, such as protein denaturation, and water holding capacity and color modifications. Storage temperatures did not have influence in the quality of PSF and PAT samples, but it showed some effects in AF muscle.Industrial relevance: This work demonstrates the potential application and benefits of high pressure (HP) in the freezing and thawing of fish meat in comparison to conventional methods, due to an improvement on the cellular integrity of the tissue. Although some negative effects are produced during processing with HP, no additional modifications occur during the frozen storage. The studied methodologies seemed to be very suitable for fish freezing and thawing, especially for products which will be frozen stored and/or cooked.