Application of an ultrasonic assisted curing technique for improving the diffusion of sodium chloride in porcine meat

Tri-frequency simultaneous ultrasound pickling for the acceleration of the NaCl content and quality improvement of pork (longissimus dorsi)

BACKGROUND

The pickling process with NaCl is an essential step for pork preservation. This study aimed to investigate the effect of different ultrasonic intensities of tri-frequency simultaneous ultrasound (TSIU) pickling on the NaCl content and quality of pork (longissimus dorsi). After 30 min pickling, the NaCl content, moisture content, pickling yield, cooking loss, textural properties, color, pH, moisture migration and distribution as well as microstructure of pork were assessed.

RESULTS

Results showed that among all the ultrasonic treatment intensities (85-150 W L-1), the NaCl content of the sample pickled by an intensity of 101.3 W L-1 was higher than that of other intensities. TSIU 101.3 W L-1 showed 59.95% higher NaCl content than the control sample. In addition, the sample treated with TSIU of 101.3 W L-1 had higher pickling yield and moisture content, better textural properties of pork (including hardness and chewiness), and less cooking loss. The results of the low-field nuclear magnetic resonance showed that, compared with the control group, the relaxation time T21 of the ultrasound-assisted pickling samples increased, while the proportion of T22 (A22) reduction ranged from 175.0% to 379.9%. The microstructure designated that the ultrasonic treatment could facilitate changes in meat texture.

CONCLUSION

Ultrasound marination of different intensities promoted the diffusion of NaCl and affected the quality of pork tenderloins. The TSIU at 101.3 W L-1 could better accelerate NaCl transport and homogeneous distribution on meat, thereby improving the sample quality. © 2024 Society of Chemical Industry.

Effects of brining, ultrasound, and ultrasound-assisted brining on quality characteristics of snakehead (Channa argus) fillets

The change of quality characteristics in snakehead fillets were investigated during brining, ultrasound, and ultrasound-assisted brining processing. Results showed that ultrasound and brine had significantly impact on the tissue microstructure and the color parameter of fillets. Compared to 60-min marination in deionized water, the shear force was reduced by 17.67 g by ultrasound, compared to 80-min marination in deionized water, the shear force was reduced by 28.68 g by brine. Brine significantly increased the water-holding capacity of fish fillets. Ultrasound resulted in increased random coils, β-turn and hydrophobic interaction, while brine significantly promoted the formation of the α-helix structure. The increase of the thermal stability of the myosin head was due to the synergistic effect of ultrasound and brine, but the decrease of the thermal stability of actin only associated with brine. The study provides the reference for the application of ultrasound-assisted brining technology to aquatic industry.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01506-8.

Application of ultrasound treatment in pork marination: Effects on moisture migration and microstructure

To better understanding the effects of ultrasonic marination on the porcine tissue, the moisture migration and microstructure were investigated in this study. Additionally, the acoustic field distribution was analysis using COMSOL Multiphysics. The low-filed NMR results demonstrated that ultrasonic curing induced a leftward shift in T21 and a rightward shift in T22, accompanied by a significant reduction in A22, thereby enhancing the water-holding capacity of pork. The SEM and TEM observation showed that the presence of larger interstitial gaps between muscle fibers facilitated the diffusion of NaCl. The simulation analysis revealed that the acoustic field at 26.8 kHz showed minimal standing wave effects and more pronounced cavitation, which was the main reason for the best curing effect at this frequency. The scale-up test showed the NaCl content in pork reached 1% after ultrasound curing, indicating the potential application of ultrasonic marination technology in domestic refrigerators.

Evaluation of low-temperature ultrasonic marination of pork meat at various frequencies on physicochemical properties, myoglobin levels, and volatile compounds

This study aims to evaluate the pork meat quality after ultrasonic brining at different frequencies, thereby providing a more comprehensive understanding of the effects of ultrasound marination on meat. The texture profile analysis showed that ultrasonic curing at various frequencies significantly improved the textural properties of samples, especially at 26.8 kHz, resulting in a reduction of tenderness, hardness, and chewiness values by 44%, 43%, and 44%, respectively. The cooking loss of samples marinated by ultrasound decreased from 27% without ultrasonic treatment to 22%, indicating a significant improvement in water-holding capacity, while the changes in pH had only a subtle impact on pork quality. Meanwhile, the color of pork became more rosy hue due to decreased L⁎ values and increased a⁎ values, which was mainly attributed to an elevated proportion of oxymyoglobin and reduced metmyoglobin content. Additionally, ultrasonic marination did not exert a negative impact on the oxidation of pork protein and lipids. After roasting, samples marinated by ultrasound exhibited a significantly higher abundance of volatile flavor compounds compared to static marinated meat (with an increase of 16 flavor substances) and fresh pork (with an increase of 24 flavor substances), demonstrating the efficacy of ultrasonic marination in enhancing the overall flavor and taste profile of pork. Consequently, the application of ultrasonic technology holds great potential for the "home kitchen type" rapid marination.

The Application of High-Intensity Ultrasound on Wet-Dry Combined Aged Pork Loin Induces Physicochemical and Oxidative Alterations

This research investigated the synergic outcome of high intensity ultrasound (HIU) treatment and wet-dry combined aging (WDCA) on physiochemical characteristics and lipid oxidation during refrigerated storage to ameliorate pork meat's quality and shelf life. The CIE b* values, cooking loss (CL %), and pH of the HIU treated samples were higher than those of the control over the aging period. They were significantly (p<0.05) modified by the aging period and ultrasound (US) treatment. However, the released water (RW %) and moisture were not significantly influenced by US treatment (p>0.05). The Warner-Bratzler shear force of HIU-treated samples was lower over control values except in 7-14 d, and it showed a significant difference between control and US treatment according to the significance of HIU (p<0.05). The thiobarbituric acid reactive substance of HIU-treated samples was significantly higher (p<0.05) than control values over the aging period. These results suggested that HIU treatment and WDCA showed a synergistic effect of maximizing the tenderness, but lipid oxidation was higher than before ultrasonic treatment. In agreement with this, the most favorable approach would involve implementing wet aging for a period of two weeks followed by dry aging for a period not exceeding one week after the application of HIU.

Evaluation of ultrasound and pulsed electric field combinations on the cooking Losses, texture Profile, and Taste-Related amino acids of chicken breast meat

The search to improve the quality of meat while maintaining its nutritional value and flavor profile has driven the investigation of emerging clean-label non-thermal technologies in the field of meat processing. Ultrasound (US) and pulsed electric field (PEF) treatments have emerged as promising tools for producing high-quality meat products. This study investigated the combined effects of ultrasound and PEF on chicken breast meat quality, focusing on cooking loss, texture, and taste-related amino acids. Ultrasound (24.5 kHz, 300 W, 10 min) combined with PEF for 30 s (1.6, 3.3, and 5.0 kV/cm as US + PEF 1, US + PEF 3, and US + PEF 5, respectively) significantly reduced cooking losses (up to 28.78 %), potentially improving the product yield. Although US + PEF significantly (p < 0.05) affected pH, particularly at a higher PEF intensity (5 kV/cm), the overall color appearance of the treated meat remained unchanged. The combined treatments resulted in a tenderizing effect and decreased meat hardness, adhesiveness, and chewiness. Interestingly, US + PEF with increasing PEF intensity (1.6 to 5.0 kV/cm) led to a gradual increase in taste-related amino acids (aspartic acid, glutamic acid, etc.), potentially enhancing flavor. FTIR spectra revealed alterations in protein and lipid structures following treatment, suggesting potential modifications in meat quality. Scanning electron microscopy (SEM) revealed significant changes in the texture and structure of US + PEF-treated meat, depicting structural disruptions. Furthermore, Pearson's correlation analysis and principal component analysis (PCA) revealed a clear relationship between the physicochemical characteristics, free amino acids, color, and texture attributes of chicken meat. By optimizing treatment parameters, US + PEF could offer a novel approach to improve chicken breast meat quality.

Effect of the temperature and ultrasound on salt impregnation process of haddock

The influence of different brine temperatures (5, 15 and 25 °C) and ultrasound on the salt gain (SG) and water gain (WG) kinetics of haddock cubes during vacuum impregnation (VI) process was evaluated. Samples were taken from salt solution (4 g NaCl/ 100 g solution) after 0, 20, 40, 60, 100, 140 and 180 min of brining process for salt and moisture analysis. Ultrasound assisted VI and increasing temperature in the salt solution increased (P < 0.05) the salt content, and SG value in the haddock cubes. Furthermore, ultrasound assisted VI enhanced the water diffusion into the cubes and resulted in an increase in WG value. The ultrasound process increased the salt effective diffusion coefficient (Ds) and the highest Ds was found at 25 °C brine temperature. Azuara, Diffusive, Peleg, Weibull, Z and L models were tested to predicting SG and WG kinetics and Azuara was the best model during brining process of haddock cubes.

Recent advancements in the utilization of ultrasonic technology for the curing of processed meat products: A comprehensive review

Curation meat products involves multiple stages, including pre-curing processing (thawing, cleaning, and cutting), curing itself, and post-curing processing (freezing, and packaging). Ultrasound are nonthermal processing technology widely used in food industry. This technology is preferred because it reduces the damages caused by traditional processing techniques on food, while simultaneously improving the nutritional properties and processing characteristics of food. The utilization of ultrasonic-assisted curing technology has attracted significant attention within the realm of meat product curing, encouraging extensive research efforts. In terms of curing meat products, ultrasonic-assisted curing technology has been widely studied due to its advantages of accelerating the curing speed, reducing nutrient loss, and improving the tenderness of cured meats. Therefore, this article aims to comprehensively review the application and mechanism of ultrasound technology in various stages of meat product curing. Furthermore, it also elaborates the effects of ultrasonic-assisted curing on the tenderness, water retention, and flavor substances of the meat products during the curing process. Besides, the implication of the ultrasound in the processing of meat curation plays a potent role together with other technologies or methods. The use of ultrasound technology in the process of meat curation was analyzed, which might be a theoretical insight for the industrialization prospects of the meat product.

Effects of ultrasound-assisted intermittent tumbling on the quality of cooked ham through modifying muscle structure and protein extraction

BACKGROUND

Tumbling treatment is widely used in the production of cooked ham. However, traditional intermittent tumbling (IT) treatment is time-consuming. To enhance the tumbling efficiency, high-intensity ultrasound was used to assist IT treatment (UIT).

RESULTS

UIT treatment reduced the tumbling time and significantly improved the water holding capacity, tenderness, sliceability and texture of cooked ham compared to IT treatment. Furthermore, more violent destruction of meat tissue was exhibited in the UIT treatment. This change facilitated extraction of more salt-soluble protein, which in turn welded meat pieces tightly and improved the quality of the cooked ham.

CONCLUSION

UIT treatment could accelerate the tumbling process and enhance the quality of cooked ham. These results may provide guidance on effective strategies for a high-quality meat production process. © 2023 Society of Chemical Industry.

Evaluation of ultrasound-assisted process as an approach for improving the overall quality of unsmoked bacon

Our previous study has found that ultrasonic application on raw meat could improve the flavor of unsmoked bacon. For comprehensively evaluating the impacts of ultrasonic pretreatment (0, 250, 500 or 750 W, 20 kHz) on the overall quality of unsmoked bacon during processing, the following indicators were determined including salt and water content, pH, shear force, color, water distribution, texture and myofibril microstructure. Results manifest that ultrasonic pretreatment could significantly improve the salt and water content, pH and redness of unsmoked bacon. The water retention capacity was obviously enhanced by ultrasonic pretreatment proved by increased immobile water and decreased free water. Meanwhile, the shear force, the hardness and the chewiness were notably ameliorated after ultrasonic pretreatment, suggesting a better tenderness verified by the observation results of transmission electron microscope. However, no significant differences were found on the brightness, yellowness, springiness, cohesiveness and resilience of unsmoked bacon after ultrasonic pretreatment. Consequently, ultrasound could be considered as a potential tool for the overall-quality improvement of unsmoked bacon.

Mass transfer modeling during wet salting of caiman meat (Caiman crocodilus yacare) at different brine temperatures

Caiman meat is considered exotic and its consumption has significantly increased due to its nutritional quality. This study aimed to evaluate the kinetics of water content (WC) and salt content (SC) at different temperatures (1, 5, 10 and 15 °C) and to evaluate the use of mathematical models to predict the mass transfer kinetics until equilibrium conditions during the wet salting of caiman tail fillets. Moisture and chloride analyses were performed throughout the wet salting process. Four models (Peleg; Weibull; Zugarramurdi and Lupín; Diffusion) were tested to predict WC and SC kinetics in caiman tail fillets subjected to wet salting. The increase in the temperature resulted in a reduction (P < 0.05) in WC and an increase (P < 0.05) in SC. Nonlinear effects on WC and SC kinetics were observed between the different temperatures evaluated. Furthermore, the effective diffusion coefficients (D_w and D_s) increased (P < 0.05) with increasing temperature. Peleg, Weibull, Zugarramurdi and Lupín, and the Diffusion model satisfactorily represented WC and SC rates throughout the process. The kinetic behavior of the parameters of the models corroborated the effects of temperature on those parameters. Peleg was the best model for predicting WC and SC kinetics, and Zugarramurdi and Lupín was the best for predicting the equilibrium conditions of the process (WC^∞ SC^∞), all parameters which can be used to describe the mass transfer kinetics during wet salting of caiman tail fillets.

Effect of two-stage heating treatment on physicochemical properties of shrimp (Penaeus vannamei) meat

BACKGROUND

Changes in the physicochemical properties of shrimp meat treated with two-stage heating were investigated. Currently, shrimp products in the processing process are susceptible to uneven dehydration, shrimp meat shrinkage, which results in rough and hard texture, poor chewiness, and seriously affects the edible quality as well as economic benefits. Improving the utilization value of shrimp resources, expanding its market shares, optimizing the tenderness of shrimp is the key to developing new types of fresh and ready-to-eat shrimp products.

RESULTS

The results indicated that preheating at 30 °C could not affect the quality of shrimp meat significantly (P > 0.05). As the preheating temperature increased from 40 °C to 50 °C, the hardness and shear force of shrimp meat decreased due to the exposure of protein hydrophobic groups, protein aggregation and degradation, muscle fraction broken, and weight loss increase. Further increase in preheating temperature would lead to further aggregation and gelation of proteins, causing hardness and shear force increase. Besides, the results of microstructure showed that preheating at 40 °C and 50 °C could cause the shrimp muscles to become loose.

CONCLUSION

This study showed that the preheating temperature ranging from 40 °C to 50 °C could effectively improve the tenderness of shrimp meat. This study might be useful for developing tenderized shrimp products in the future. © 2022 Society of Chemical Industry.

Processing Smoked Pork Loin Using Ultrasound-Assisted Curing

The objective of this study was to evaluate the impact of high intensity ultrasound (HIU)-assisted brining on the physicochemical characteristics and consumer preference of smoked pork loin (Longissimus dorsi, LD). LD cuts (5 × 8 × 2.5 cm, length × width × height) were randomly distributed in a 2 × 2 design of two concentration of brine (5 or 10% NaCl) and two methods of brining (static, TC; or HIU for 30 min). After brining, the samples were smoked, cooled, vacuum packed and stored for 7 d at 4 °C. Weight, pH, percentage of NaCl, water-holding capacity (WHC), shear force and colour characteristics were evaluated in post-brining and smoked samples. Sensory analysis was performed to evaluate preference in appearance, taste, and texture characteristics. Weight and NaCl increased in samples post-brining. However, smoked pork samples were not significantly different among treatments. The smoked samples became more yellow and less red. Consumers preferred TC smoked pork based on this appearance characteristic. HIU improved NaCl concentrations in cured pork meat. Under these conditions, it is necessary to consider the posterior treatment that the ultrasonicated-cured meat will undergo, since part of the weight gain was lost during the smoking process.

Sonoprocessing: mechanisms and recent applications of power ultrasound in food

There is a growing interest in using green technologies in the food industry. As a green processing technique, ultrasound has a great potential to be applied in many food applications. In this review, the basic mechanism of ultrasound processing technology has been discussed. Then, ultrasound technology was reviewed from the application of assisted food processing methods, such as assisted gelation, assisted freezing and thawing, assisted crystallization, and other assisted applications. Moreover, ultrasound was reviewed from the aspect of structure and property modification technology, such as modification of polysaccharides and fats. Furthermore, ultrasound was reviewed to facilitate beneficial food reactions, such as glycosylation, enzymatic cross-linking, protein hydrolyzation, fermentation, and marination. After that, ultrasound applications in the food safety sector were reviewed from the aspect of the inactivation of microbes, degradation of pesticides, and toxins, as well inactivation of some enzymes. Finally, the applications of ultrasound technology in food waste disposal and environmental protection were reviewed. Thus, some sonoprocessing technologies can be recommended for the use in the food industry on a large scale. However, there is still a need for funding research and development projects to develop more efficient ultrasound devices.

Application of simultaneous ultrasonic curing on pork (Longissimus dorsi): Mass transport of NaCl, physical characteristics, and microstructure

This study aimed to investigate the effect of ultrasound curing with various working modes and frequency combinations, including mono-, dual- and tri-frequency, on the content of NaCl and tenderness of pork loins (Longissimus dorsi). The physical qualities, myoglobin, moisture migration, distribution, and microstructure of pork were also evaluated. The results displayed that the NaCl content of samples cured by simultaneous ultrasound (100 W/L) working mode with a frequency combination of 20, 40, and 60 kHz was higher than that of other ultrasound working modes. The effect of ultrasonic brining was significantly better than the static curing when the saline solution was >35 mL. In addition, the samples cured by simultaneous ultrasound had better physical qualities, including more pickling absorptivity, less cooking loss, and lower hardness, tenderness, and chewiness value. The intensity of lightness was reduced, although redness and yellowness remained unaltered compared to static curing. The myoglobin content decreased drastically without changing the oxygenation level, and the relaxation time of T_2b and T₂₁ was delayed. The microstructure indicated that the ultrasonic treatment could promote changes in meat texture. Overall, the simultaneous ultrasound at various frequencies could efficiently accelerate NaCl penetration and improve pork quality.

Effect of Novel High-Intensity Ultrasound Technique on Physio-Chemical, Sensory Attributes, and Microstructure of Bovine Semitendinosus Muscle

The present study aimed to evaluate the effects of high-intensity ultrasound (HIU) application on meat quality traits, sensory parameters, and the microstructure of semitendinosus muscle from Hanwoo cattle. The samples were treated in an ultrasonic bath (35 kHz) at an intensity of 800 W/cm² for 60 min, followed by aging at 1°C for 0, 3, and 7 days. The application of ultrasound resulted in lower Warner-Bratzler shear force and higher myofibrillar fragmentation index values during the storage period. HIU also enhanced the tenderness, flavor, umami, and overall acceptability of cooked beef muscle. However, the electronic tongue evaluation results showed higher umami values in the control treatment on the seventh day of storage. The microstructure of sonicated meat showed disorganized myofibrillar architecture and swelling in the A-band region of sarcomeres during the storage period, which led to greater meat tenderness. The heatmap illustrated the high abundance of α-linolenic acid (C20:5n3) and eicosapentaenoic acid (C18:3n3) in sonicated meat samples on the third day of the storage. These results showed that HIU is a potential method for tenderizing and improving the sensory attributes of beef without compromising other quality aspects.

Understanding the effects of ultrasound processng on texture and rheological properties of food

The demand for the production of high quality and safe food products has been ever increasing. Consequently, the industry is looking for novel technologies in food processing operations that are cost-effective, rapid and have a better efficiency over traditional methods. Ultrasound is well-known technology to enhance the rate of heat and mass transfer providing a high end-product quality, at just a fraction of time and energy normally required for conventional methods. The irradiation of foods with ultrasound creates acoustic cavitation that has been used to cause desirable changes in the treated products. The technology is being successfully used in various unit operations such as sterilization, pasteurization, extraction, drying, emulsification, degassing, enhancing oxidation, thawing, freezing and crystallization, brining, pickling, foaming and rehydration, and so forth. However, the high pressure and temperature associated with the cavitation process is expected to induce some changes in the textural and rheological properties of foods which form an important aspect of product quality in terms of consumer acceptability. The present review is aimed to focus on the effects of ultrasound processing on the textural and rheological properties of food products and how these properties are influenced by the process variables.

Impact of Combining Tumbling and Sous-Vide Cooking Processes on the Tenderness, Cooking Losses and Colour of Bovine Meat

This study investigated the effect of combining tumbling and sous-vide cooking processes on the tenderness, cooking losses and colour of bovine Semitendinosus (ST) muscles sampled from Charolais-breed cows. Half of the ST muscles were tumbled for 12 h with a compression rate of 40%. All muscle samples, whether tumbled or not, were then sous-vide cooked at 50 °C, 60 °C or 80 °C for 1 h or 4 h. After cooking, we measured the shear forces (SF), cooking losses, total water content and the main colour characteristics of pre-tumbled and non-tumbled meat pieces. Pre-tumbled meat pieces had 20% lower SF values than non-tumbled meat pieces, regardless of the cooking conditions applied. All meat pieces cooked at 50 °C had significantly higher (p < 0.05) SF values and lower (p < 0.05) cooking losses than meat pieces cooked at 60 °C or 80 °C. Pre-tumbled meat pieces showed significantly lower cooking losses (p < 0.001) than non-tumbled meat pieces. Applying the tumbling process before cooking led to an increase in meat colour lightness values (p < 0.001), and the colour parameters were significantly affected (p < 0.05) by temperature, cooking time, and temperature × cooking time interaction. Combining a 12-h tumbling process with cooking at 60 °C appears to provide the best compromise between increasing meat tenderness and limiting cooking losses.

Gelling Characteristics of Emulsions Prepared with Modified Whey Protein by Multiple-Frequency Divergent Ultrasound at Different Ultrasonic Power and Frequency Mode

The effect of ultrasonic frequency mode (mono, dual and tri-frequency) and ultrasonic power (0–300 W) on structural properties (intrinsic fluorescence and sulfhydryl content) of whey protein was studied. Emulsions prepared with modified whey protein were used to form the heat-set gels, and the properties of whey protein emulsion gels (WPEG) and their digestion were investigated. The textural and rheological properties of WPEG prepared using whey protein pretreated by mono and dual-frequency ultrasound at the power between 180–240 W were enhanced, while those of WPEG prepared with whey protein pretreated by triple-frequency above the power of 180 W were declined. WPEG prepared using whey protein pretreated by dual-frequency ultrasound (DFU) with the power of 240 W had the highest hardness and storage modulus which were 3.07 and 1.41 times higher than the control. The microstructure of WPEG prepared using DFU pretreated whey protein showed homogeneous and denser networks than those of the control according to the results of confocal laser scanning microscope (CLSM). The modification in the microstructure and properties of the WPEG prepared using DFU pretreated whey protein delayed the protein disintegration during the first 30 min of gastric digestion when compared with control. Whereas the release rate of free amino group of the WPEG prepared using whey protein modified by ultrasonic pretreatment increased during the intestinal phase when compared with that of control. The results indicated that using dual-frequency ultrasound to modify whey protein is more efficient in improving the properties of WPEG, and ultrasonic power should be considered during the application of ultrasound pretreatment in producing protein gels. The fine network of WPEG prepared with whey protein pretreated by ultrasound resulted in better hardness and storage modulus. Partially unfolding of the protein induced by ultrasound pretreatment might make the whey protein more susceptible to the digestive enzyme. Our results could provide new insights for using ultrasound as the potential processing tool on designing specific protein emulsion gels as the delivery system for nutrients.

Mass transfer enhancement of tuna brining with different NaCl concentrations assisted by ultrasound

The influence of different NaCl concentrations (2.5, 5, 7.5 and 10% (w/w)) on the mass transfer kinetics of tuna during brining process with and without ultrasound assistance was evaluated. Results showed that an increase in NaCl concentration and the application of ultrasound accelerated the salt diffusion in the tuna muscle, and the highest yield was obtained in 5% brine concentration. Moreover, the kinetics parameters were significantly affected by the NaCl concentration and ultrasound application during brining. The values of the mass transfer kinetics parameters (k₁, k₂) for total and water weight changes decreased as NaCl concentration increased with and without ultrasound assistance during brining. In contrast, the higher the NaCl concentration, the higher the value of the salting kinetics parameters for salt weight changes. The application of ultrasound enhanced the salt effective diffusion coefficient (De) from 402.8% to 653.21% during the brining process, and the highest De was also found at 5% brine concentration. The application of ultrasound can improve the uniformity of salt distribution, enhance water holding capacity, reduce hardness and chewiness, but have no significant effect on color of tuna muscle.

Effects of Radio Frequency Tempering on the Temperature Distribution and Physiochemical Properties of Salmon (Salmo salar)

Salmon (Salmo salar) is a precious fish with high nutritional value, which is perishable when subjected to improper tempering processes before consumption. In traditional air and water tempering, the medium temperature of 10 °C is commonly used to guarantee a reasonable tempering time and product quality. Radio frequency tempering (RT) is a dielectric heating method, which has the advantage of uniform heating to ensure meat quality. The effects of radio frequency tempering (RT, 40.68 MHz, 400 W), water tempering (WT + 10 °C, 10 ± 0.5 °C), and air tempering (AT + 10 °C, 10 ± 1 °C) on the physiochemical properties of salmon fillets were investigated in this study. The quality of salmon fillets was evaluated in terms of drip loss, cooking loss, color, water migration and texture properties. Results showed that all tempering methods affected salmon fillet quality. The tempering times of WT + 10 °C and AT + 10 °C were 3.0 and 12.8 times longer than that of RT, respectively. AT + 10 °C produced the most uniform temperature distribution, followed by WT + 10 °C and RT. The amount of immobile water shifting to free water after WT + 10 °C was higher than that of RT and AT + 10 °C, which was in consistent with the drip and cooking loss. The spaces between the intercellular fibers increased significantly after WT + 10 °C compared to those of RT and AT + 10 °C. The results demonstrated that RT was an alternative novel salmon tempering method, which was fast and relatively uniform with a high quality retention rate. It could be applied to frozen salmon fillets after receiving from overseas catches, which need temperature elevation for further cutting or consumption.

Effects of washing step and salt-addition levels on textural and quality properties in the chicken-surimi products

The massive wastewater from surimi manufacture and salt addition is controversial. In our previous study, a chicken-surimi (CS) product can be successfully developed from the spent-hen breast via 3 times of washing steps and 2.5% salt addition in the recipe. Due to the characteristics of broiler breast (higher protein contents in muscle), this study was to optimize the washing step for CS batter recovered from broiler breast and the salt-addition level in the CS-product recipe. The step of washing once with 0.1% salt solution showed no (P > 0.05) differences in the texture profile and color parameters (expect a* value) in CS batters compared to initial washing steps (a 3-step washing procedure). The CS batter obtained by this washing step had higher amino-acid contents than boiler breast and large Grade A egg and even fit adults’ daily essential amino-acid requirement. Besides, the lower (P < 0.05) water loss of cooked CS products during the storage (4°C) was shown beyond 2.0% salt addition in CS products. For efficient/ecofriendly extraction and sodium-content reduction, the washing once with a 0.1% salt solution and 2% salt addition in the recipe is recommended in the CS batter recovered from broiler breast and its products, respectively.

The Physicochemical, Microbiological, and Structural Changes in Beef Are Dependent on the Ultrasound System, Time, and One-Side Exposition

The effect of high-intensity ultrasound (HIU) system (bath, 37 kHz and 90 W/cm2; or probe, 24 kHz and 400 W) and application time (25 or 50 min, one-side exposition) on the properties of bovine Longissimus lumborum after 7 d of storage at 4 °C was studied. The bath system significantly increased the lightness of the muscle, while other color parameters (a*, b*, hue, and chroma) were not different from the control. The water holding capacity and shear force decreased significantly (3.1-5% and 0.59-0.72 kgf, respectively) in sonicated meat independently of the system, favoring the tenderization of the muscle after storage. Microstructural changes observed in the HIU-exposed surface provided evidence of a higher area of interfibrillar spaces (1813 vs. 705 µm2 in the control), producing tenderization of the muscle, compared with the control. HIU significantly increased counts of total aerobic and coliform bacteria, especially after 50 min of ultrasonication. HIU also increased lactic acid bacterial counts in the bath system. Single-sided muscle exposition to ultrasound may produce sufficient significant changes in muscle properties, which could decrease long treatment times that would be needed for the exposition of both sides. HIU in bath systems increases tenderness by modifying meat ultrastructure, with no significant changes in physicochemical parameters. Nevertheless, microbiological quality may need to be considered during the process due to a slight increase in bacterial counts.

Effects of ultrasound pretreatment on the quality, nutrients and volatile compounds of dry-cured yak meat

The objective of the present study was to assess the effects of ultrasound pretreatment on the quality of dry-cured yak meat. The ultrasonic power with 0, 200, 300 and 400 W (ultrasonic frequency of 20 kHz) were used to assist processing of dry-cured yak meat. The meat quality, nutrient substances, sensory quality, electronic nose, electronic tongue and volatile compounds of dry-cured yak meat were determined. The results indicated that the moisture content and hardness value of ultrasonic treatment group was significantly lower compared to the control group (P < 0.05). Ultrasonic treatment increased the value of b*, and decreased the value of L*, a*, pH, chewiness, melting temperature and enthalpy. Springiness value significantly increased from control group to 300 W of ultrasonic power group. Shear force significantly decreased with the increase of ultrasonic power (P < 0.05). Ultrasonic treatment had no effect on the TVB-N content, but it could increase the TBARS content. Ultrasonic treatment could significantly increase the essential FAA (EFAA) and total FAA (P < 0.05). In addition, the saturated fatty acid (SFA) content significantly increased with the increase of ultrasonic power (P < 0.05). Ultrasound treatment negatively affected the meat's color, smell, and taste but increased its tenderness and the overall acceptability. It also significantly increased alcohols and aldehydes contents (P < 0.05), which were consistent with the measurement of electronic nose and electronic tongue. The results demonstrated that the the appropriate ultrasonic power assisted in the processing improves quality of dry-cured yak meat, particularly for the power of 300 W.

Effect of ultrasonic thawing on the physicochemical properties, freshness, and protein-related properties of frozen large yellow croaker (Pseudosciaena crocea)

Ultrasonic treatment (UT) was used to thaw large yellow croaker in this study, and the effect of various ultrasonic power levels on the quality of large yellow croaker was evaluated after thawing. The effects of ultrasonic on water holding capacity (WHC), moisture distribution, thiobarbituric acid-reactive substance (TBARs), total volatile base nitrogen (TVB-N), ATP degradation (related to K value), surface color change, free amino acid (FAA) content, total sulfhydryl group (SH) content, Fourier transform infrared absorption spectra (FT-IR), fluorescence emission spectra, and microscopic observations of large yellow croaker myofibrillar proteins were investigated. The thawing times of the control sample, 200UT, 240UT, 280UT, and 320UT samples were 1750, 1190, 810, 580, and 570 s, respectively, which indicated that ultrasonic radiation could improve thawing efficiency. Additionally, ultrasonic thawing maintained better freshness and color and inhibited lipid oxidation. Compared with fresh samples, the TVB-N of large yellow croaker thawed by ultrasonication increased by 12.68%, and the K value increased by 0.9%. The 240UT sample had tightly arranged myofibrils and fewer changes in the structures of myogenic fibrillar proteins than the fresh samples, and the SH content of 240UT was decreased by 8.17%. Use of excessive ultrasonic power (320 W) damaged the protein microstructure and the microstructure of large yellow croaker. In conclusion, sample 240UT maintained the quality of large yellow croaker better with minimal damage, which is recommended for rapid thawing. PRACTICAL APPLICATION: Ultrasonic waves improve the thawing efficiency of large yellow croaker and maintain the freshness and color of the fish. According to results, sample 240UT exhibited slight changes in the structure of the myofibril protein, but excessive ultrasonic power destroyed the microstructure and protein structure. Appropriate ultrasonic treatment to the thawing of fish has good prospects.

Impact of Tumbling Process on the Toughness and Structure of Raw Beef Meat Pieces

Tenderness is a major factor in consumer perception and acceptability of beef meat. Here we used a laboratory tumbling simulator to investigate the effectiveness of the tumbling process in reducing the toughness of raw beef cuts. Twelve Semitendinosus beef muscles from cows were tumbled according to four programs: T1 (2500 consecutive compression cycles (CC), for about 3 h), T2 (6000 CC, about 7.5 h), T3 (9500 CC, about 12 h), and T4 (13,000 CC, about 16 h). The effect of tumbling on the toughness of raw meat was assessed using compression tests (stresses measured at 20% and 80% of deformation ratios) and microscopic observations made at the periphery and centre of meat samples, and compared against non-tumbled controls. Longer tumbling times significantly reduced the stresses measured at 20% and 80% compression rates, which reflected the toughness of muscle fibres and connective tissue, respectively. At the microscopic level, longer tumbling times led to reduced extracellular spaces, increased degradation of muscle structure, and the emergence of amorphous zones. A 12-h tumbling protocol ultimately makes the best compromise between the process time demand and toughness reduction in beef Semitendinosus meat pieces.

Influence of ultrasound-assisted tumbling on NaCl transport and the quality of pork

The present study aimed to investigate the impact of ultrasound-assisted tumbling (UAT; 20 kHz, 100, 300, 500 and 700 W) with different treatment time (30, 60, 90 and 120 min) on the diffusion and distribution of NaCl as well as the change of pork texture properties during curing. Results showed that in comparison with the single tumbling (ST), the NaCl content and the NaCl diffusion coefficient were increased along with UAT treatment (P < 0.05). The scanning electron microscopy and the energy dispersive X-ray analysis showed that UAT treatment changed the microstructure of pork which may facilitate the NaCl dispersion homogeneously. In addition, the moderate UAT treatment of 300 W with 60 min could significantly improve the tumbling yield, water-holding capacity and textural properties of pork compared with the ST treatment (P < 0.05). Meanwhile, in comparison with the ST group, protein extraction was considerably increased after UAT (300 and 500 W) treated for 120 min (P < 0.05). Our study demonstrated that UAT treatment could effectively promote the penetration and distribution of NaCl and improve pork meat quality via facilitating the extraction of meat protein.

Effects of thermoultrasonic treatment on characteristics of micro-nano particles and flavor in Greenland halibut bone soup

In order to investigate the effects of thermoultrasonic treatment (TUT) on the formation of colloidal micro-nano particles (MNPs) and the quality of halibut bone soup, nutrients, particle characteristics, and flavor characteristics were analyzed. The morphology of MNPs was studied using an optical microscope. Results showed that TUT could increase the nutrient content (total sugars, 22.15 mg/100 mL; water soluble proteins, 173.24 mg/mL; fatty acids, 1779.7 mg/100 mL; solids, 3.16 g/100 mL), reduce the particle size (605.92 nm) and interfacial tension. Meanwhile, TUT make the halibut bone soup has better emulsifying characteristics and stability. The contents of flavor substances, such as esters, 5'-nucleotides, organic acids in the halibut bone soup were more abundant, while the contents of hexanal and 1-octen-3-ol and fishy off-flavor were reduced in TUT group. The overall odor and taste outline were more harmonious. Therefore, TUT can be used in the production of high quality fish bone soup, and TUT could be considered as a good deep processing technology for halibut bone and improve economic efficiency.

Ultrasonication of beef improves calpain-1 autolysis and caspase-3 activity by elevating cytosolic calcium and inducing mitochondrial dysfunction

The objective of this study was to investigate if ultrasonication of bovine longissimus thoracis et lumborum (LTL) steaks increases calpain-1 and caspase-3 activities, and if so, to explore the underlying mechanisms that trigger their activation. Post-rigor bovine LTL steaks were subjected to ultrasonication at 40 kHz and 12 W/cm² for 40 min and subsequently aged for 14 d at 4 °C. Ultrasonication improved beef tenderness (P < 0.05) without negatively impacting pH, color, or cook loss (P > 0.05). Improved tenderness in the ultrasonicated steaks was associated with greater degradation of titin, desmin, troponin-T, and calpastatin and increased calpain-1 autolysis and caspase-3 activity (P < 0.05). In addition, ultrasonicated steaks had greater levels of cytosolic calcium and reactive oxygen species and lower mitochondrial oxygen consumption rate (P < 0.05). These data indicate that improved beef tenderness following ultrasonication is, in part, a function of increased calpain-1 and caspase-3 activities, potentially by elevating cytosolic calcium and inducing mitochondrial dysfunction, respectively.

Evaluation of ultrasound and microbubbles effect on pork meat during brining process

In this study combined effect of ultrasound-induced acoustic cavitation and microbubbles during meat brining on pork loin (Longissimus dorsi) was evaluated. Cylindrical shape (diameter 15 mm, height 80 mm) pork loin samples were cut and immersed in 200 g L^-1 NaCl brine and treated with the following brining methods for 180 min: static brining (SB), ultrasound assisted brining (US) and ultrasound combined with microbubbles in brine (USMB). Ultrasound was generated with 20 kHz frequency, 5,09 W/cm² maximum intensity and 100 W maximum power. Microbubbles in brine were produced by a gas-liquid mixing pump. Effect of ultrasound and microbbubles on NaCl content and diffusion in pork loin, mass balance, water binding capacity (WBC), protein denaturation and meat tissue microstructure were evaluated. The US and USMB brinings enhanced the NaCl diffusion into meat compared to meat brined under static conditions. The constant diffusion coefficient (D) model precisely described the NaCl diffusion kinetics during brinings. The ultrasound and microbbubles resulted in microscopic pores on the surface of myofibers. Decreasing WBC was observed for all brining methods. Myosin was not detectable in any of the brining methods. Denaturation temperature of actin showed a decreasing tendency with increasing brining time independently the brining methods.

Improvement of quality and flavor of salted egg yolks by ultrasonic assisted cooking

Physicochemical, texture indexes, microstructure and volatiles were used to characterize the changes in quality, structure and flavor of cooked salted egg yolks (SEYs) with or without ultrasonic treatment. Experimental results indicated that ultrasonic significantly increased cooking (water) loss, oil exudation, lipids oxidation (TBARS), accelerated the doneness of cooked SEYs and then promoted the generation of volatiles. These results were further confirmed by the improvement of thermal stability, the changes in color, secondary structure of proteins, water distribution and mobility. Meanwhile, more "fragments" and "cracks" were observed in scanning electron microscope (SEM) and the decrease in gumminess and chewiness were detected using texture profile analysis (TPA), inducing that the migration of lipids and collapse of gel network were intensified. Moreover, ultrasonic treatment decreased the content of sodium chloride in SEYs. Therefore, it was concluded that the doneness, quality and flavor of cooked SEYs were improved by ultrasonic treatment, which could be used as an effective and alternative method for the production of SEYs with good flavor, sandy and oily texture.

Effect of ultrasonic pre-treatment on Ara h 1 in peanut sprouts

Ara h 1 is the most abundant sensitizing protein in peanuts; it has high thermal stability and is difficult to degrade. The peanut sprout is a high-quality, natural food that has various beneficial effects and lower allergenicity than peanut seeds. In this study, ultrasonication (US) of peanut sprouts was used to alter their Ara h 1 content. We determined that the optimal parameters for the US process were 35 °C temperature, 30 min duration, 240 W power, and 100 kHz frequency. After 5 days of germination, the protease activity of the control (blank) group increased to 262.39 ± 0.10 U, whereas that of the US group increased to 290.1 ± 0.25 U. We also investigated the effects of US on Ara h 1 protein composition, structure, and related gene expression during germination. ELISA results showed that after 5 days of germination, Ara h 1 content in the blank group decreased from 20.63 ± 0.31 ppm to 3.35 ± 0.42 ppm, whereas in the US group, they decreased to below the detection limit. SDS-PAGE bands between 50 and 70 kDa from peanut sprout extracts gradually became lighter in both groups. The band almost disappeared at day 5 of germination in the US group, indicating that US reduced the Ara h 1 content of peanut sprouts, consistent with the ELISA results. The expression of the Ara h 1 gene in peanut seeds was 173.92 ± 26.37. In the BK control group, it decreased to 0.49 ± 0.17 on the fourth day and increased slightly to 0.75 ± 0.09 on the fifth day. In the US group, it decreased to 1.37 ± 0.28 on the first day, dropped sharply to 0.00 on the third day, and increased slightly to 0.04 ± 0.01 on the fourth and fifth days. Protein structure results showed that the α-helix structure of Ara h 1 decreased after US, whereas the content of β-fold structures increased. The surface hydrophobicity decreased, and the secondary and tertiary structures of Ara h 1 were loose.

Application of ultrasound-assisted vacuum impregnation for improving the diffusion of salt in beef cubes

The aim of this study was to investigate the effect of different vacuum impregnation (VI) conditions (Control, VI-250, VI-500, VI-750, US-VI-250, US-VI-500 and US-VI-750) on the salt gain (SG) and water gain (WG) kinetics of beef cubes. The cubes were immersed in brine solution (4 g NaCl/ 100 g solution) and salted at different levels of vacuum (250, 500 and 750 mbar) using VI method with and without ultrasound. The final moisture and salt contents of the cubes were 78.60% and 1.59%, respectively, and the samples were salted the fastest with US-VI-250. Five kinetic models were selected to evaluate the SG and WG kinetics, and Azuara model exhibited the best fit. In addition, the salt (D_s) and moisture (D_w) diffusion coefficients were in the range of 5.94-8.11 × 10^-9 m²/s and 5.17-8.64 × 10^-9 m²/s, respectively. It can be concluded that the ultrasound-assisted VI could shorten the brining time by improving the salt diffusion in beef cubes.

Ultrasonic treatment increased functional properties and in vitro digestion of actomyosin complex during meat storage

We investigated the effects of ultrasonic treatment (400 W, 20 kHz, 45.52 W/L) and storage time (0 d, 3 d, 7 d and 10 d) on functional properties, structural changes and in vitro digestion of actomyosin complex isolated from vacuum-packed pork. As storage time increased, turbidity, surface hydrophobicity, active sulfhydryl and total sulfhydryl of actomyosin complex increased, while protein solubility decreased. Ultrasonic treatment increased surface hydrophobicity, protein solubility and active sulfhydryl content but decreased turbidity and total sulfhydryl content compared with the control. Ultrasonic treatment caused a reduction in α-helix content on 0 day and the fluorescence intensity of tryptophan and tyrosine residues. It increased pancreatin digestibility of actomyosin complex and the number of peptides of smaller than 1 kDa. However, it decreased the number of peptides. The findings provide a new insight into the application of appropriate ultrasonic treatment to promote meat digestibility.

Innovative Characterization Based on Stress Relaxation and Creep to Reveal the Tenderizing Effect of Ultrasound on Wooden Breast

In order to explore a new strategy to characterize the texture of raw meat, based on the ultrasonic tenderized wooden breast (WB), this study proposed stress relaxation and creep to determine the rheological properties. Results showed that hardness was significantly decreased from 3625.61 g to 2643.64 g, and elasticity increased, after 600 W ultrasound treatment at 20 kHz for 20 min (on-time 2 s and off-time 3 s) at 4 °C. In addition, based on the transformation of creep data, a new indicator, slope ε'(t), was innovatively used to simulate a sensory feedback of hardness from the touch sensation, proving WB became tender at 600 W treatment due to the feedback speed to external force. These above results were confirmed by the reduced shear force, increased myofibril fragmentation index (MFI), decreased particle size, and increased myofibrillar protein degradation. Histology analysis and collagen suggested the tenderizing results was caused by muscle fiber rather than connective tissue. Overall, stress relaxation and creep had a potential to predict meat texture characteristics and 600 W ultrasound treatment was an effective strategy to reduce economic losses of WB.

Ultrasound-assisted thawing of frozen white yak meat: Effects on thawing rate, meat quality, nutrients, and microstructure

The objective of this study was to assess the effects of ultrasound-assisted thawing (UAT) on the quality of longissimus dorsi muscles from white yak meat (WYM). Ultrasonic power levels of 0, 200, 400, and 600 W (frequency of 20 kHz) were used to assist thawing. The thawing rate, meat quality, nutrient substances, volatile compounds, and microstructure of the WYM were determined. The results showed that ultrasonic thawing treatment reduced thawing times by 30.95-64.28% compared to control. The meat quality results revealed that the thawing loss, cooking loss, L* and b* values, and pH values decreased significantly while the a* value and cutting force increased significantly (P < 0.05) at the lower 400 W power level compared with the control. In addition, the free amino acid (FAA), mineral, and vitamin (especially water-soluble vitamins) contents were significantly (P < 0.05) increased with the ultrasound treatment. UAT significantly (P < 0.05) increased the content of volatile compounds, an effect that was highest in the UAT-400 W group. Partial least squares discrimination analysis (PLS-DA) showed that 2,4-heptadienal was critical in distinguishing the UAT groups from the control. When the ultrasonic power was lower than 400 W, the muscle cell area was significantly (P < 0.05) increased but decreased when higher power was used. Therefore, UAT improves the thawing efficiency and quality of frozen WYM, particularly at a power level of 400 W, and these findings have potential applications in the meat industry.

Effect of a moderate electric field on the salting of Atlantic Salmon (Salmo salar): An experimental study and phenomenological understanding

Salting is one of the oldest methods of preserving food. The main limitation of salting is its extended processing time due to slow salt diffusion. A moderate electric field (MEF) can improve the mass transfer rate through electroporation. Regularly, mass transfer processes are modeled with Fick's second law. However, due to the anisotropic nature of food microstructures, it might be more appropriate to use an anomalous model. The main objective of this study was to search for a phenomenological explanation for salt and water diffusion in the salmon brining process coupled with MEF. Salmon fillets were cut into finite cylinders (0.025 × 0.025 m) and brined in two salt concentrations (6 and 24% w/w NaCl) at 6 °C for 20 h. MEFs were applied in the range of 0 to 2 V/cm. The salt and water contents of the salmon were measured during the process. Fick's second law and anomalous model based on fractional calculus were used to describe the diffusion phenomena. The results showed that an MEF tended to reduce the brining processing time and increase the salt content of salmon. This effect is predominantly due to an increase in the equilibrium salt concentration in the salmon tissue. Mathematical analysis shows that the anomalous diffusion model is more suitable for representing the brining process, exhibiting superdiffusion behavior (α > 1). An MEF accelerates the salt mass transfer into salmon tissue even at lower temperatures, significantly reducing the processing time. In addition, the diffusion process can be characterized with an anomalous model.