Evaluation of various salt contents on quality characteristics with or without curdlan of pork myofibrillar protein gels and the development of low-salt pork sausages

The objective of this study was to evaluate the gelling properties of pork myofibrillar protein (MP) gels at various salt concentrations with or without curdlan, and its application to model sausages with reduced salt levels. When curdlan was incorporated into MP mixtures, cooking yield (CY) at 0.15 m salt was similar to that of 0.45 m salt (P > 0.05). Gel strength of MPs at 0.45 m salt was highest among other salt concentrations. Increased salt concentration tended to be high shear stress values, regardless of the presence of curdlan (P < 0.05). MP gels with increasing salt concentration showed fewer pores and swollen structures. Addition of curdlan improved CY and expressible moisture of low-fat model sausage with increased salt levels. The addition of curdlan at 1.0% salt reduced the hardness and gumminess, and similar to those at 1.5% without curdlan. These results indicated that curdlan improved the water-holding capacity and textural properties of low-fat and low-salt sausage.     

脂肪含量对低盐猪肉凝胶品质的影响

以未添加磷酸盐的低盐猪肉凝胶作为研究对象,考察脂肪添加量(0～20%)对猪肉凝胶保水、质构和色泽的影响。结果显示,脂肪添加量在15%～20%范围内,凝胶保水性显著增加(P<0.05);添加5%以上的脂肪,可显著提高猪肉凝胶的L*值(P<0.05);在脂肪添加量不高于5%条件下,猪肉凝胶可形成良好的硬度、弹性、凝聚性和咀嚼性,并能保持较好的红度值(a*值),利于开发低脂猪肉制品。     

低脂和低盐萨拉米发酵香肠的研究进展

萨拉米发酵香肠具有营养价值高及风味独特等优点,深受消费者喜爱。与大部分肉制品相比,传统萨拉米发酵香肠中食盐（约8%）和脂肪（约32%）含量较高,长期食用高脂高盐食品可能会诱发心脑血管疾病,因此,降低萨拉米发酵香肠中食盐和脂肪添加量势在必行。本文综述了近年来萨拉米发酵香肠的降脂、降盐方法,介绍了非热加工技术在低脂和低盐萨拉米发酵香肠中的应用,为优化低脂和低盐萨拉米发酵香肠提供理论参考。     

Design and nutritional properties of potential functional frankfurters based on lipid formulation, added seaweed and low salt content

The aim of this paper was to design and analyse the nutritional composition (fatty acid profile, cholesterol, mineral and amino acid content) of low-fat frankfurters enriched with n−3 polyunsaturated fatty acids (PUFA) (using algal oil to add 400 mg of docosahexanoic acid – DHA/100 g of product) as affected by the addition of seaweed (5.5% Himanthalia elongata) and the partial substitution (50%) of animal fat by olive oil (as a source of monounsaturated fatty acids – MUFA) or combinations of olive oil and seaweed. Reduction of NaCl level was also studied. The presence of algal oil produced frankfurters with high long-chain n−3 PUFA contents. The partial substitution of the pork fat by olive oil reduced (P < 0.05) saturated fatty acids (SFA) and promoted (P < 0.05) MUFA. A healthier lipid formulation (algal and olive oils and the reducing animal fat) produced a good balance of MUFA/SFA, PUFA/SFA and n−6/n−3 ratios. Although adding seaweed had little effect on the lipid and amino acid profiles of frankfurters, it does constitute a means to produce low-sodium products with important dietary fibre content, with better Na/K ratios and rich in Ca.     

Effect of an outdoor rearing system on the welfare, growth performance, carcass and meat quality of a slow-growing rabbit population

The effect of Outdoor or Indoor housing systems on the growth, welfare and carcass and meat quality of a local rabbit population was investigated. The slaughter age was 103 ± 2 days. Open-field tests showed an effective capacity of the Outdoor group to combat stressors. Compared to Indoor rabbits, Outdoor rabbits showed better growth performance and higher slaughter weight (SW) (2535 vs 2137 g; P < 0.01). Outdoor housing conditions increased the physical activity of rabbits and their hind legs were more developed (36.1% vs 34.9%; P < 0.01). Slaughter yield was lower in Outdoor rabbits (57.8% vs 58.4% SW; P < 0.05) due to the higher skin proportion (17.2% vs 15.6% SW; P < 0.05). Outdoor rabbit meat showed lower L* value (L. lumborum: 55.6 vs 59.2; P < 0.01; B. femoris: 53.0 vs 55.5; P < 0.01) and cooking loss (L. lumborum: 15.9% vs 18.1%; P < 0.05). Outdoor rabbit hind leg meat was characterized by lower water (74.5% vs 75.1%; P < 0.01) and higher protein (22.9% vs 22.6%; P < 0.01) and fat (1.4% vs 1.1%; P < 0.01) contents; lipids were lower in SFA and higher in MUFA. Outdoor rearing seems to be a possible alternative housing system that allays the ethical concerns of modern consumers while also providing good meat quality.     

Comparison of hydrostatic and hydrodynamic pressure to inactivate foodborne viruses

The effect of high hydrostatic pressure (HPP) and hydrodynamic pressure (HDP), in combination with chemical treatments, was evaluated for inactivation of foodborne viruses and non-pathogenic surrogates in a pork sausage product. Sausages were immersed in distilled water, 100-ppm EDTA, or 2% lactoferrin, and then inoculated with feline calicivirus (FCV), hepatitis A virus (HAV) or bacteriophage (MS2, phiX174, or T₄). Each piece was packaged individually and subjected to pressure by either HDP, HPP (500 MPa, 5 min, 4 °C), or control (no pressure). On sausages immersed in water, HPP and HDP significantly (P < 0.05) reduced titers of FCV by 2.89 and 2.70 log₁₀ TCID₅₀/ml, and HAV by log₁₀ 3.23 and 1.10, respectively, when compared to non-pressure-treated controls. Titers of T₄ (1.48 and 1.10 log₁₀ PFU/g) and MS2 (1.46 and 0.96 log₁₀ PFU/g) were also significantly reduced by HPP and HDP treatments, respectively, in combination with water. Inoculation of viruses and bacteriophage on a meat product may have protected viruses from complete inactivation by pressure treatments.

Industrial relevance

This is the first study to directly compare hydrostatic and hydrodynamic pressure technologies to inactivate microorganisms. This is also the first study to examine the inactivation of viruses and bacteriophages by pressure technology in a deli meat product. This study shows that viruses attached to meat surfaces may be protected from complete inactivation by hydrostatic and hydrodynamic pressure treatments, and these findings require more investigation into the survival of viruses in deli 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.     

Combination treatment of high-pressure and CaCl2 for the reduction of sodium content in chicken meat batters: effects on physicochemical properties and sensory characteristics

A combination of high-pressure processing (HPP, 200 MPa, 10 min) and CaCl₂ (0.2%, w/w) on the cooking loss (CL), expressible moisture (EM), textural properties (hardness, springiness, cohesiveness, chewiness and firmness) and sensory attributes of reduced-sodium (1.25% NaCl) chicken meat batters (RCMB) was investigated. The results revealed that combining HPP with CaCl₂ significantly decreased EM, elevated sensory properties and acted synergistically in reducing CL and improving hardness, chewiness and firmness, which enabled RCMB to obtain quality characteristics similar to those with high salt (2.5% NaCl) content. These changes brought about by combined HPP and CaCl₂ could be attributed to increased apparent viscosity and proportion of immobilised water, enhanced rheological (elastic) properties and a denser, homogeneous protein gel network with evenly dispersed small fat globules. It is interesting to take advantage of the synergy between moderate HPP and low concentrations of CaCl₂ to develop meat products with reduced sodium content.     

Development and quality evaluation of cooked buffalo tripe rolls

Cooked buffalo tripe rolls (BTRs) were prepared from a combination of buffalo tripe (75%) and buffalo meat (25%) by using mincing (M-BTR) and blade tenderization (BT-BTR). They were stored at 4 ± 1 °C and studied for various physico-chemical, sensory and microbial qualities. Significantly (P < 0.01) higher pH, shear force value, diameter shrinkage and fat percentage were observed in M-BTR and BT-BTR than control product (100% minced buffalo meat). The product yield and drip loss percentage were significantly (P < 0.01) lower in BT-BTR, whereas drip loss percentage was significantly higher in M-BTR compared to controls and BT-BTR. No significant change was noticed in protein and moisture content between the different products. All physico-chemical parameters and sensory evaluation scores of M-BTR were comparable with control. Significant (P < 0.01) increases were noticed in pH, moisture content, thiobarbituric acid and tyrosine values with increasing storage period, whereas the extract release volume decreased significantly. All microbial counts and sensory evaluation scores were within the acceptable limits until 15 days of storage at 4 ± 1 °C in low-density polyethylene pouches stored aerobically.     

Dietary administration of ewe diets with a distillate from rosemary leaves (Rosmarinus officinalis L.): Influence on lamb meat quality

The effect of including distilled rosemary leaf in the diet of pregnant ewes on subsequent lamb meat quality was studied. Thirty-six Segureña ewes were randomly assigned to three homogeneous groups. One group was fed a basal diet (BD) as control while the diet of the other two groups was modified by substituting 10% (R₁) and 20% (R₂) of the BD with a pellet made from 50% barley and 50% of distilled rosemary leaves (DRL). Meat spoilage (TVC, PSY and MYC), TBARS, CIELab coordinates and the sensory characteristics contribution of fresh lamb meat packed in MAP (70% O₂:30% CO₂) were analyzed on days 0, 7, 14 and 21. In general, R₁ and R₂ had higher a^* values, better scores for meat and fat colour (P < 0.05) and lower TBARS and rancid odour (P < 0.05), than the control samples. The total viable count was lower in meat DRL. No statistically significant differences were detected between the two treatments (10–20% DRL).     

Relationship between rheological,textural and melting properties of dark chocolate as influenced by particle size distribution and composition

In dark chocolate, rheological properties during processing are influenced by particle size distribution (PSD), fat and lecithin contents with consequential effects on finished texture and melting characteristics. Multivariate regression, correlation and principal component analyses (PCA) were used to explore their interrelationships. A 4 × 3 × 2 factorial experiment was conducted with varying PSD [D ₉₀ (90% finer than this size) of 18, 25, 35 and 50 μm], fat (25, 30 and 35%) and lecithin (0.3 and 0.5%). Rheological properties (yield stress and apparent viscosity), textural properties (firmness, index of viscosity and hardness) and melting index (duration) were respectively measured using shear rate-controlled rheometer, TA.HD Plus texture analyzer and differential scanning calorimetry. The PSD, fat and lecithin contents significantly influenced all rheological, textural properties and some melting characteristics. Increasing particles sizes reduced yield stress, apparent viscosity, firmness, index of viscosity, hardness and melting index of products with greatest influence with 25% fat and 0.3% lecithin, reduced with increasing fat and lecithin contents. There were high correlation (r = 0.78–0.99) and regression coefficients (R ² = 0.59–0.99) among the rheological, textural and melting index indicating their high inter-relationships. In PCA, the rheological, textural and melting index accounted for >95% variance in the data.     

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.     

Evaluation of fish meat noodles: physical property,dough rheology,chemistry and water distribution properties

The present study reports the rheological, textural, structural and water distribution properties of fish meat noodles. The results showed that storage and loss modulus were increased when 20% fish meat was added while decreased with the addition of >20% fish meat, whereas loss rate behaved vice versa. The moisture and fat content increased significantly (P < 0.05) while water absorption index was decreased upon the increment of fish meat compared to control. Lightness of dough and hardness of noodles decreased significantly (P < 0.05) while redness and yellowness were increased. Similarly, less swelled starch granules and dominancy of protein network over starch granules were observed in microstructure. The amount of free water was increased while bound water was decreased when >20% fish meat was added during low-field nuclear magnetic resonance. The findings suggest the feasibility of adding 15–20% fish meat for the proper structure and chemistry of noodles.     

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.     

High pressure processing pretreatment of Chinese mitten crab (Eriocheir sinensis) for quality attributes assessment

The present study evaluated high pressure processing (HPP) pretreatment effects on the quality attributes of Chinese mitten crab (Eriocheir sinensis). Process parameters were optimized (300 MPa for 5 min) and the effects of HPP pretreatment on the total edible part of Eriocheir sinensis were investigated. The results showed that steamed loss has no significant difference and water holding capacity of inner meat was increased by approximately 51.33% with HPP pretreatment. HPP pretreatment can also decrease hardness value of crab carapace and preserve texture properties of crab leg meat. Compared with raw inner meat, results of DSC analysis of inner meat with HPP pretreatment has revealed that the denaturation temperature and the enthalpy of protein were decreased remarkably. The results of water distribution indicated that HPP pretreatment reduced the loss of entrapped water in inner meat. Finally, compare with the conventional steamed crabs, it has been detected that the aroma of the edible viscera of crabs has a significant difference with HPP pretreatment. Above findings indicated that HPP pretreatment retains quality attributes of Eriocheir sinensis well, in the meantime improves the processing efficiency since steaming time can be reduced by applying HPP pretreatment.Industrial relevanceHPP is a novel non-thermal technique widely used in the field of food production. Compared with conventional thermal processing, it is important for assessing the impact of HPP pretreatment on the quality attributes of crab in order to obtain high-quality products. According to recent studies, HPP pretreatment has been confirmed to be able to improve the quality of hot processed crabs. By applying 300 MPa for 5 min on Eriocheir sinensis, the total edible part was improved, and the water holding capacity of crab inner flesh was increased. Moreover, HPP pretreatment can also decrease hardness value of crab carapace and preserve sensorial properties of crab leg meat. These results indicated HPP pretreatment retains high quality characteristics of Eriocheir sinensis and reduces steaming time by which means the processing efficiency can be improved. This work provided further support for the use of HPP in Eriocheir sinensis.     

Characteristic of low-salt solid-state fermentation of Yunnan oil furu with Mucor racemosus: microbiological,biochemical, structural,textural and sensory properties

The effect of reducing salt on the microflora, enzymatic activity and structural, textural and sensory properties of Yunnan oil furu was studied. Oil furu with different salt content, including 11 (control), 9%, 7% and 5%, were prepared. The results showed that lower salt increased fungus and lactic acid bacteria growth, yielding a tastier product. In addition, pathogenic bacterium such as Staphylococcus aureus and Salmonella were not detected in Yunnan oil furu during low-salt solid-state fermentation, and the Escherichia coli was <3 MPN g⁻¹. Enzymatic activity decreased slower in low-salt fermented products, leading to more protein hydrolysis. Consequently, the free amino acids and free fatty acids increased significantly. Reduced salt also improved the structural, textural and sensory properties, such as giving a more consistent structure, better spreadability and a better sensory evaluation.     

Optimization of textural properties of reduced-fat and reduced-salt emulsion-type sausages treated with high pressure using a response surface methodology

This study optimized the high pressure conditions for development of a reduced fat sausage. A three-factor-three-level Box–Behnken design was adopted to study the simultaneous effects of one compositional variable (15, 20 and 25% fat content) and two processing variables (150, 200 and 250 MPa high pressure, along with 5, 6 and 7 min high pressure treatment time) on firmness of emulsion-type sausages. Analysis of variance (ANOVA) was performed to evaluate the potential interactive and quadratic effects between these variables. The results revealed that, the optimum processing conditions for an optimum gel setting were 22.19% fat content, 197.30 MPa high pressure and 5.92 min pressure treatment time. The adequacy of the model equation for predicting the optimum response values was effectively verified. In conclusion, the emulsion-type meat sausages using a novel high pressure based processing method were preferred for their improved textural properties and reduced fat content.Industrial relevanceFor health reasons, there is a need to reduce fat content of processed meat products. This study developed a novel processing method using high pressure to produce emulsion-type meat sausages with reduced-fat, with improved functional qualities, including objective appearance, textural properties and sensory evaluation. Importantly, this was achieved with a model, mainly based on prediction of the firmness of the pressure treated sausages with reduced fat contents.     

Changes in fatty acids and polar material of restructured low-fat or walnut-added steaks pan-fried in olive oil

The study aims to determine the influence of pan-frying on the fatty acid composition and fat content and alteration of functional restructured beef steaks. Low-fat (L, 2% fat), 20% walnut-added (W, 13% fat) and medium fat (M, 13% fat) steaks were prepared and fried in extra virgin olive oil. Pan-frying increased fat in L and W steaks and decreased it in M ones. Raw L and M steaks showed similar fatty acid profiles while W ones contained a lower percentage of saturated fatty acids (SFA) and monounsaturated fatty acids (MUFA) but a higher percentage of polyunsaturated fatty acids (PUFA). The fatty acid profile of fried steaks was between that of the raw steaks and olive oil. Several fatty acids (g fatty acid/100 g edible steaks) were affected (p < 0.001) by the frying × meat-formulation interaction. Linoleic and linolenic acid contents did not decrease in fried W steaks, but decreased (p < 0.05) when data were expressed on a dry matter basis.Frying increased SFA, MUFA and ω-6 PUFA contents in L samples while it decreased SFA and increased ω-6 PUFA in M steaks. Before and after frying, W steaks had atherogenic and thrombogenic indexes at least three times lower than their counterparts. Both indexes decreased in fried L samples while only the AI in M ones. Polar material content (PM) increased only in L samples. No relevant differences were found between PM of the fried steaks and that of their corresponding used oils. Results suggest that pan-frying improves the fatty acid composition of L and M steaks with minor changes in PM. The high retention of lipids observed in the W samples permits consumption of ω-3 PUFA- and ω-6 PUFA-enriched meat with a very low content of alteration compounds.     

Ohmic cooking of whole beef muscle – Optimisation of meat preparation

Uniform ohmic heating of solid foods primarily depends on the uniformity of electrolyte distribution within the product. Different preparation techniques were tested in an attempt to ensure an even salt dispersion within a full beef muscle (biceps femoris). Meat pieces were soaked, injected and tumbled using a range of procedures before ohmic cooking at pasteurization temperatures. A final preparation method (multi-injection (five points) with a 3% salt solution followed by 16 h tumbling) was validated. Selected quality parameters of the ohmically cooked products were compared to steam cooked products. Ohmically heated meat had a significantly (P < 0.05) uniform lighter and less red colour. Cook loss was significantly lower (P < 0.05) in ohmic samples and in relation to tenderness ohmic heated samples were tougher (P < 0.05) though the difference was only 5.08 N. Comparable cook values were attained in the ohmic and conventionally cooked products.     

Development of a healthy low-fat fish sausage containing dietary fibre

In order to develop a healthy low-fat fish sausage containing dietary fibre (DF), three fundamental changes were made to an ordinary pork sausage recipe: incorporation of 4% (w/w) of Swelite^® (a DF obtained from inner pea), different levels of pork meat replacement (0%, 50% and 100%) by hake mince and the combination of varying amounts of Fibruline^® (a DF obtained from chicory root) and hake mince (Fibruline: additional hake mince, 2.6:5.2, 5.2:2.6 and 7.8:0.0, % w/w) as a substitute for pork fat. It was found that the addition of Swelite to pork sausage favoured greater gel strength and hardness. On the contrary, increasing levels of pork meat replacement by hake reduced the sausages’ gel strength and hardness. Finally, sausages without pork fat showed promising textural and colour parameters. High-Fibruline sausages were less cohesive and chewable than pork fat sausages (control), but also exhibited a greater gel strength. Low-Fibruline ones presented almost all textural properties similar to the control, with exception of hardness and gumminess. Therefore, regarding some key textural parameters, it was possible to produce low-fat fish sausages similar to the ordinary pork sausages.