Power ultrasonic on mass transport of beef: Effects of ultrasound intensity and NaCl concentration

The effects of ultrasound intensity and salt concentration of brining for accelerating brine transfer into beef were evaluated. Samples were analyzed with NaCl and water content, effective diffusion coefficient and microstructure. Results showed that ultrasound intensity and NaCl concentration of brine could significantly affect NaCl and moisture content at different treating time during meat brining (p < 0.05). According to the calculation of diffusion coefficients (D), measured and calculated data were consistent indicating the fitness of the applied model. The D values of NaCl or water significantly increased with ultrasound intensity while the salt concentration was slightly affected by D values of NaCl or water. These facts could be confirmed by microstructural analysis with TEM which illustrated that the space of separation of myofibrils improved with ultrasound intensity. However, with the different salt concentration of brining, ultrasound intensity 20.96 W/cm² caused a nearly consistent result of myofibrils ruptured but significantly better than other ultrasound intensity (p < 0.05). Therefore, ultrasound could be considered a potential method to accelerate the brining process in meat products.Industrial relevanceIn our research, the ultrasound intensity could significantly affect diffusion coefficients (D) of NaCl or water while the salt concentration with ultrasound processing was slightly affected the values of D, these results indicated that in industrial application, we might focus on the effect of ultrasound intensity. In addition, along with the emerging technology, this could reduce the amount of NaCl supplemented in brining and shorten the processing time.     

(23)Na-MRI quantification of sodium and water mobility in pork during brine curing

A model study on movements of sodium ions in pork loin during brining was carried out using ²³Na-magnetic resonance imaging (²³Na-MRI). Samples of different pH and post-mortem age were mounted in Plexiglas^® cylinders with built-in phantoms and cured in 18.9% and 18.1% NaCl (w/v), respectively. One-dimensional ²³Na-MRI and apparent diffusion coefficient (ADC) profiles were obtained over 5 days with intervals of 24 h. On day 5 the meat was cut into 1 cm slices and analyzed for chloride content. ²³Na-MRI and ADC profiles of meat provided detailed non-destructive information about salt and water movements during brine curing. Quantification of salt concentration in meat by one-dimensional ²³Na-MRI profiling proved successful at values above 0.9 g NaCl/100 g sample in the meat. ²³Na measurements were calibrated against chemically determined chloride, yielding a linear relationship. ²³Na-MRI profiles suggested that the diffusion of salt into whole meat cuts cannot be described by simple ordinary Fickian diffusion with a constant diffusion coefficient. The diffusion coefficient is suggested to be affected by changes in NaCl concentration, swelling and degree of dehydration.     

High intensity ultrasound effects on meat brining

Pork loin (longissimus dorsi) samples of two different geometries, cylinders and slabs, were immersed in saturated NaCl brine for 45 min under different conditions: without brine agitation (STAT), with brine agitation (AG) and with ultrasound application (US) at eight levels of ultrasonic intensity. Moisture content change and NaCl gain were considered in order to evaluate the difference in the brining treatments. No significant differences were found in moisture and NaCl content of samples treated under STAT conditions and AG conditions, while the influence of ultrasound on the mass transfer process during meat brining depended on the intensity applied. There was an ultrasonic intensity threshold above which the influence of ultrasound appeared. At the highest level of intensity studied, the water content of samples was significantly higher than the initial water content of meat. As regards NaCl transfer, once above the intensity threshold, the increase in the NaCl content was proportional to the applied ultrasonic intensity. Not statistically significant differences were found for sample geometry.     

Mass Transfer During Ripening of Cuartirolo Argentino Cheese

The mass transfer occurring during ripening of Cuartirolo Argentino cheese was mathematically modelled as an effective diffusion process. The model contained the final NaCl concentration profile resulting from the brining step as starting point and used the same effective diffusivity of NaCl as for brining. The equation developed allowed the calculation of the equilibrium salt concentration resulting from different brining times. Theoretical results were compared against experimental data showing very good agreement.     

Application of vacuum impregnation and CO2-laser microperforations in the potential acceleration of the pork marinating process

The marination of meat takes many hours to attain the required salt content. Vacuum impregnation (VI) and CO₂-laser microperforation have been studied to accelerate the mass transfer process and show promising results. The objective of this study was to investigate the feasibility of reducing the pork marinating time by coupling CO₂-laser microperforation and VI processes and mathematically with Fick's second law and anomalous diffusion models. Pork cylinders were microperforated and marinated with a solution containing NaCl (8% w/w) and Na₅P₃O₁₀ (0.3% w/w) at 6 °C for 60 h. The marinating process was modeled using Fick's second law and anomalous diffusion models. The marinating process coupling VI and microperforations significantly accelerated the mass transfer compared with that of the conventional salting process, reducing the marinating processing time by 47.8%. The anomalous diffusion model was better at representing and adjusting the experimental data compared than the model based on Fick's second law.Industrial applicationThe marinating of meat is a process commonly applied in the meat industry, which focuses on enhancing the flavor, tenderness and juiciness of meat. However, it is a time-consuming process. Laser microperforation is a pretreatment performed on the meat in which the laser acts as a drill, creating micropores in the meat, which coupled with vacuum impregnation can be applied to accelerate the marinating process of pork meat. Applying both technologies, it is possible to reduce the processing time by almost 48%, which can relevantly and significantly increase plant productivity.     

Influence of high intensity ultrasound application on mass transport,microstructure and textural properties of pork meat (Longissimus dorsi) brined at different NaCl concentrations

The aim of this work was to evaluate the effect of high intensity ultrasound and NaCl concentration on the brining kinetics (5 ± 1 °C) of pork loin as well as its influence on the textural and microstructural changes. In order to identify the effect of both factors on NaCl and moisture transport, kinetics were analyzed by taking the diffusion theory into account. The textural and microstructural analysis of raw and brined meat both with and without ultrasound application was carried out. The experimental results showed that the brine NaCl concentration not only determined the final NaCl content in meat samples but also the direction of water transport. The NaCl and moisture effective diffusivities were improved by ultrasound application. The final NaCl and moisture content and the ultrasound application promoted changes in instrumentally measured meat texture, which were confirmed via microstructural observations.     

Kinetics studies during NaCl and KCl pork meat brining

We describe and quantify salt transfer processes during food processing using mathematical models. Our approach incorporates as novel elements: (i) a more rigorous determination of the salt diffusion kinetics by using the salt concentration of the liquid phase instead of the salt concentration of the overall samples, (ii) the use of novel, more accurate equilibrium conditions, (iii) the consideration of mass transfer coefficients in the boundary and (iv) the consideration of diffusion and salt transfer coefficients as functions of time. The methodology is used to determine the NaCl and KCl diffusion and transport coefficients during pork meat salting. Our results, combining experimental studies with a numerical study of a mathematical optimization problem point out the limitations of purely diffusive models and the need for more sophisticated models accounting for more physical and chemical processes taking place in meat during salting.     

Diffusion of Nitrite and Nitrate Salts in Pork Tissue in the Presence of Sodium Chloride

ABSTRACT: The objective of the present work was to analyze the effect of NaCl concentration on the diffusion coefficients of NaNO₂ and KNO₃ in pork tissue using unsteady techniques. Concentrations of nitrite and nitrate as a function of immersion time were determined in cylinders of meat using spectrophotometric techniques; experiments were performed at 4 °C and 20 °C. The unsteady state mathematical formulation was applied considering radial mass transfer. The diffusion coefficients were obtained fitting the theoretical curves to experimental data. An increase of the salt diffusivities in the tissue was observed when the diffusion occurred at high NaCl concentrations. This fact could not be explained by the Maxwell-Stefan theory. Penetration of high NaCl concentration in a tissue may affect the cellular structure leading to higher diffusion coefficients.     

超声波协同真空卤煮牛肉过程中的传质动力学分析

以牛腱子肉为研究对象,通过不同真空卤煮、不同超声功率协同真空卤煮、不同超声频率协同真空卤煮3种卤煮方式卤制牛肉,测定卤煮过程中卤牛肉的食盐、水分和质量变化,研究超声波协同真空卤煮牛肉的传质规律。结果表明：食盐含量变化随着真空度、超声波功率和频率的增加而增大,水分含量变化与质量变化随着真空度、超声波功率和频率的增加而减小。卤煮过程中卤牛肉食盐含量变化的动力学参数k1、k2与真空度、超声功率和频率的大小有关;真空度-0.043 MPa、超声波频率28 kHz、功率1 000 W下,食盐含量变化的有效扩散系数De值最大,为1.42×10-4 m2/s,3种卤煮方式的传质驱动力与t0.5/l具有很好的线性关系。真空卤煮与超声协同真空卤煮对卤牛肉的微观结构有显著影响。因此,超声协同真空卤煮对卤牛肉中的传质有显著影响,能促进传质进程,超声波协同真空卤煮最佳传质条件为真空度-0.043 MPa,超声频率28 kHz,超声功率1 000 W,超声时间30 min。     

超声波处理对湿腌猪肉腌制速度及肉质的影响

主要研究了超声功率、超声时间与间歇时间比、超声时间对湿腌猪肉腌制速度及肉质的影响。实验结果表明,超声波处理可以加速腌制液中食盐、亚硝酸盐和蔗糖向湿腌猪肉的渗透,加快腌制速度,并且增加肉的保水性,提高肉的嫩度,将蒸煮损失控制在合理范围之内。通过L9(34)正交实验得到超声波最佳处理工艺条件为超声功率300W,超声时间与间歇时间比1∶1,超声处理时间90min。     

NaCl diffusion kinetics in dry salting of goat cheese

With the aim of studying diffusion during the dry salting of goat cheese, the experimental profiles of salt and water concentrations were determined in terms of time and distance from the interface. The effective diffusion coefficient was determined using Fick’s Second Law for a semi-infinite model. NaCl was not present at distances greater than 2 cm from the interface after 24 h of salting. The moisture profiles were seen to decrease from the surface farthest from the interface to the zone in contact with the salt. In contrast, salt concentrations were highest at the interface and decreased with distance from this point. The value of the effective diffusion coefficient did not vary significantly with distance from the interface, but did decrease significantly with salting time. Essentially the same phenomenon of salt incorporation was found to occur in dry salting as in brining.     

Mass Transfer Modelling During Osmotic Dehydration of Jumbo Squid (Dosidicus gigas): Influence of Temperature on Diffusion Coefficients and Kinetic Parameters

Mathematical modelling was used to study the effect of process temperature on moisture and salt mass transfer during osmotic dehydration (OD) of jumbo squid with 6% (w v ⁻¹) NaCl at 75, 85 and 95 °C. The diffusion coefficients for moisture and salt increased with temperature. Based on an Arrhenius-type equation, activation energy values of 62.45 kJ mol⁻¹ and 52.14 kJ mol⁻¹ for moisture and salt, respectively, were estimated. Simulations of mass transfer for both components were performed according to Newton, Henderson and Pabis, Page, Weibull and logarithmic mathematical expressions. The influence of drying temperature on the kinetic parameters was also studied. Based on statistical tests, the Weibull and logarithmic models were the most suitable to describe the mass transfer phenomena during OD of jumbo squid.     

Modelling the effect of temperature and lipid content on anchovy (Engraulis anchoita) salting kinetics

The effect of initial lipid content and temperature on the salting behaviour of anchovy (Engraulis anchoita) was studied. For this purpose brining of anchovy with variable initial lipid content (2.69–7.76 g 100 g⁻¹) was performed at temperatures between 5 and 35 °C. The obtained results indicate that initial mass transfer rate increased with brining temperature. Moreover, mass transfer rate was inversely related to the initial lipid content. In order to explain the dependence of the mass transfer rate on these variables two novel mathematical models were proposed. It was determined that both, salt gain and water loss rate constants depend on initial lipid content, whereas temperature only affects constants for salt transfer. In addition, salt gain constants depend linearly with initial lipid content and inversely with brining temperature. On the other hand, water loss rate constant was a function of the initial lipid content, fitting to a quadratic equation.     

Mass transfer dynamics during the acidic marination of turkey meat

The mass transfers of water, acid and NaCl in turkey meat cubes (initial volume 1 cm³ during marination were evaluated at various molalities of acetic acid (0.0-1.0) and NaCl (0.0-1.5). An experimental design was drawn up, associated with an estimate of the velocities of each component by means of kinetic monitoring. High mass yields (mass gain >0.3 kg kg⁻¹), obtained for the marinades most dilute in acid, were found only in the absence of NaCl. The presence of NaCl had a negative effect on mass yield, counterbalanced by the positive effect of acetic acid. In the case of acidic marinades with low salt concentration, high solute flux densities were observed upon the start of immersion, as well as solute transfer velocities greater than those in water. This phenomenon may be explained by the superimposition of material diffusion and transport phenomena caused by a fall in internal filtration pressure due to expansion of the protein matrix. The fall in the buffering capacity of the meat in the course of soaking, related to the leakage of proteins, dipeptides and lactates, may explain the low pH values obtained during immersion in comparison with theoretical data.     

Quantification of salt concentrations in cured pork by computed tomography

Eight pork loin samples were mounted in Plexiglas cylinders and cured for five days. Samples were scanned by computed tomography (CT) once every 24 h. At the end of the experiment, the cylinders were cut in 1 cm sections and analyzed for chloride. From image analysis of the CT images, concentration profiles were extracted and fitted to a diffusion model which included a term to account for a non-negligible mass transfer coefficient. It was found that CT provides accurate estimates of salt gradients in meat and it was suggested that this analytical method could be valuable in scientific research and product development.     

Modeling NaCl and KCl Movement in Fynbo Cheese during Salting

A model considering a ternary diffusion in axial and radial directions of a finite cylindrical solid was developed for predicting NaCl and KCl concentrations in cheese during brining. The generalized Fick's law form, negligible external mass transfer resistance, and an equilibrium between cheese and brine solution were assumed. Cheese samples (12 × 6 cm) were salted in a KCl-NaCl) brine solution. NaCl and KCl concentrations were determined experimentally and theoretically at 5, 10 and 15 hr. The average relative error of the model was higher for KCl than for NaCl and increased with brining time. The model can be applied to systems of similar geometry and conditions provided diffusion constants are known.     

Study of the influence of pulsed electric field pre-treatment on quality parameters of sea bass during brine salting

Pulsed electric field (PEF), as an emerging technique, has recently gained increased popularity in food processing and preservation. However, applications in the seafood industry are still scarce. In the present study, sea bass samples were subjected to PEF pre-treatment prior to brine salting to verify the possible acceleration of the brining rate, increasing the salt uptake and ensuring the homogeneous salt distribution in the muscle. The applied intensity of the current was set at 10 and 20 A (corresponding to a field strength of 0.3 and 0.6 kV/cm) prior to sea bass salting in brine with 5 and 10% salt concentration, respectively. The results have shown that PEF pretreatment could effectively shorten the brine salting time compared to control samples (from 5 to 2 days), or increase the salt uptake up to 77%, ensuring at the same time its homogenous distribution in the muscle. However, myofibrillar protein solubility was significantly reduced in PEF pretreated samples. At the same time, no significant differences in water holding capacity and water activity between PEF pre-treated and untreated samples were found during the whole salting period. Freezable water was influenced by PEF application, but the effect was significant only at the lowest salt concentration during the first period of the salting process.Industrial relevancePEF-assisted brining appears a promising technology in the fish processing industry due to its efficacy in reducing the salt brining time, increasing the mass transfer and enhancing the diffusion of brine into the muscle to ensure the homogeneous distribution of salt in it. The increased salt uptake of the PEF-treated samples compared to control samples shows future potentiality of using PEF prior to salting in the fish processing industry.     

Real-time PCR based on single-copy housekeeping genes for quantitative detection of goat meat adulteration with pork

Adulteration of goat meat with cheaper meat such as pork has been frequently found. Conventional PCR methods to distinguish goat meat from adulteration are qualitative, which easily produce false-positive results due to contamination but not adulteration. To address this problem, real-time PCR based on single-copy housekeeping genes encoding replication protein A1 was developed for goat meat and pork. By calculating the Ct ratio of goat meat/pork, the goat meat content in a suspected adulteration could be deduced by a good linear correlation (R² = 0.9868) in a range from 5% to 80%. Analysis of the simulated samples of goat meat showed high accuracy with recoveries of 104.91% and 105.00% for the goat meat contents of 40% and 60%, respectively, and coefficient of variations were as low as 9.24% and 9.09%. Thus, the developed assay supplied a useful tool for food regulation authorities to achieve quantitative authentication of goat meat.     

鸭腿减盐滚揉腌制过程中的传质动力学

用减盐（30% KCl＋70% NaCl）和氯化钠食盐（即普通食盐,NaCl质量分数≥99.1%）分别腌制肉鸭鸭腿,测定滚揉腌制过程中鸭腿肉总质量、水分质量分数、食盐质量分数变化情况,获得鸭腿肉在不同食盐腌制时的传质动力学数据,并进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳实验,研究不同食盐滚揉腌制过程对鸭腿肉蛋白质的影响。结果显示：氯化钠腌制和减盐腌制中鸭腿肉的总质量变化量（ΔMt0）、水分质量分数变化量（ΔMtw）以及盐分含量变化量（ΔMts）均与腌制时间的平方根（t0.5）呈现出较好的相关性,而且前4 h ΔMt0、ΔMtw以及ΔMts增长较快;氯化钠腌制和减盐腌制的有效扩散系数De分别为4.432×10－8 m2/s和4.462×10－8 m2/s,相差较小;十二烷基硫酸钠-聚丙烯酰胺凝胶电泳图谱显示两种腌制方法肌原纤维蛋白都在不断降解。综上,减盐腌制和氯化钠腌制相比,对传质速率并无明显影响。     

Influence of ultrasound on mass transport during cheese brining

 The effect of ultrasound on mass transfer during cheese brining has been investigated. The rate of water removal and NaCl gain increased when ultrasound was applied in comparison with brining performed under static or dynamic conditions, suggesting that ultrasound improves both external and internal mass transfer. A simple diffusional model was developed to simulate mass transport during acoustic brining. Model parameters were estimated using experimental data from acoustic brining experiments carried out on cheese cylinders of 1.7×10^–2m radius and 3×10^–2 m height at different temperatures (5, 15 and 20  °C). Effective water (D _W) and NaCl (D _S) diffusivities estimated using the proposed model ranged from 5.0×10^–10m²/s and 8.0×10^–10 m²/s at 5  °C to 1.3×10^–9m²/s and 1.2×10^–9 m²/s at 20  °C. Both D _W and D _S varied with temperature according to the Arrhenius equation. Through the proposed model, water losses and NaCl gains of the experiments used in the parameter identification were accurately simulated (average %var=98.2%) and also of two additional acoustic experiments carried out under different conditions of temperature (10  °C) and sample size and geometry [parallelepiped of (6×2.5×1.25)×10^–2 m] to those used in the parameter identification (average %var=98.4%). Received: 22 September 1998 / Revised version: 20 November 1998