New ultrasonic assisted technology of freezing, cooling and thawing in solid food processing: A review

Ultrasound-assisted immersion freezing method as a new strategy to improve the quality and microstructure of Chinese beef stewed dishes

Prepared dishes, as a technological extension of pre-conditioned foods and representative products of the central kitchen, are becoming a major part of people's daily diets. However, the problem of dish quality deterioration owing to freezing in the frozen supply chain has not yet been addressed, and freezing quality enhancement techniques are lacking. Herein, special equipment was used to investigate effects of ultrasound-assisted immersion freezing (UIF) on the quality of the prepared dish (braised beef with potato) and compare it with immersion freezing (IF) and conventional air freezing (AF). Results indicated that UIF effectively shortened the freezing time and improved the freezing rate of the dish. A suitable intensity of UIF treatment (150 W) improved dish quality, and high-intensity UIF treatments (300 and 450 W) caused tissue structure destruction and decreased quality. The hardness of beef and potatoes treated with UIF-150 was significantly higher than that of other treatments (P < 0.05). Scanning electron microscopy demonstrated that UIF-150 reduced the size of ice crystals and maintained the structural integrity of beef and potatoes. Porosity values of beef were 6.91 %, 2.66 %, 2.09 %, 4.30 % and 6.94 % in the AF, IF, UIF-150, UIF-300 and UIF-450 groups, respectively, and the trend of porosity in potatoes was similar to that of beef. Meanwhile, the contents of volatile flavour components in the dishes were remarkably decreased after freezing treatments, and UIF treatment could promote the retention of volatile flavour components. Results of this study provided a reference for the application of UIF technology in the frozen quality enhancement of prepared dishes and their industrialisation.

Effects of ultrasound-assisted immersion thawing in plasma-activated water on thawing rate, quality characteristics, lipid and protein oxidation of porcine longissimus dorsi

This work investigated the effects of five thawing methods (air thawing (AT), water thawing (WT), plasma-activated water thawing (PT), ultrasound-assisted water thawing (UWT) and ultrasound-assisted plasma-activated water thawing (UPT)) on thawing rate, quality characteristics, lipid and protein oxidation of porcine longissimus dorsi using fresh sample as control. The thawing time of UPT samples was significantly reduced by 81.15% compared to AT treatment (P < 0.05). The thawing loss of UPT samples was 1.55% significantly lower than AT samples (4.51%) (P < 0.05). In addition, UPT samples had the least cooking loss and centrifugal loss. UPT treatment reduced the conversion of bound and immobilized water to free water and resulted in more uniform water distribution. UPT treatment significantly decreased the thiobarbituric acid reactive substances (TBARS) value and carbonyl content and increased the total sulfhydryl content of the samples (P < 0.05). In conclusion, UPT treatment increased the thawing rate and retarded the lipid and protein oxidation, resulting in better maintenance of quality characteristics of porcine longissimus dorsi than other thawing methods.

Changes in the Objective Indices Related to Meat Quality of Porcine Longissimus Dorsi Induced by Different Thawing Methods

The quality of frozen pork is adversely affected upon thawing. In this study, the influence of various thawing methods for frozen pork, including cold water (18 °C), room temperature (18 °C), and refrigeration (4 °C) thawing, on physicochemical and nutrient substances were examined. The pork samples (a Chinese local breed: Anqing six-end-white pigs), which were thawed through the above conditions, were compared with controls (fresh porcine longissimus dorsi). Analyses were carried out to determine porcine longissimus dorsi shear force, pH value, crude protein content, antioxidant capacity, amino acid content, and fatty acid content. The results indicated that the shear force, pH value, crude protein content, total antioxidant capacity (T-AOC), and total superoxide dismutase (T-SOD) content of the porcine longissimus dorsi muscle significantly decreased via the three thawing methods compared with the control group (p < 0.05). However, malondialdehyde (MDA) content, intramuscular fat content, inosinate and cholesterol content, essential amino acid content, and umami amino acid proportion in the cold thawing group were not significantly different from the control group (p > 0.05), but there were significant differences between the other two groups. The MDA content of the air thawing and hydrostatic thawing groups significantly increased compared with the control group (p < 0.05), with it being 42.6% and 50.8% higher than the control group, respectively. In addition, the monounsaturated fatty acid content in the pork subjected to the three thawing methods significantly increased compared with the control group (p < 0.05), and the monounsaturated fatty acid content after cold thawing and hydrostatic thawing increased by 18.2% and 21.6%, respectively. In conclusion, refrigeration had less influence on the quality of the Anqing six-end-white pork and was the most suitable thawing method. This study provides a theoretical reference for frozen pork preservation for improving food quality and availing its economic benefits.

Effects of multi-frequency ultrasound-assisted immersion freezing processing on myofibrillar protein structure and lipid oxidation of large yellow croaker (Larimichthys crocea) during long-time frozen storage

In this study, large yellow croaker (Larimichthys crocea) was frozen using multi-frequency ultrasound-assisted freezing (MUIF) with different powers (160 W, 175 W, and 190 W, respectively) and stored at -18 °C for ten months. The effect of different ultrasound powers on the myofibrillar protein (MP) structures and lipid oxidation of large yellow croaker was investigated. The results showed that MUIF significantly slowed down the oxidation of MP by inhibiting carbonyl formation and maintaining high sulfhydryl contents. These treatments also held a high activity of Ca2+-ATPase in the MP. MUIF maintained a higher ratio of α-helix to β-sheet during frozen storage, thereby protecting the secondary structure of the tissue and stabilizing the tertiary structure. In addition, MUIF inhibited the production of thiobarbituric acid reactive substances value and the loss of unsaturated fatty acid content, indicating that MUIF could better inhibit lipid oxidation of large yellow croaker during long-time frozen storage.

Effect of magnetic nano-particles combined with multi-frequency ultrasound-assisted thawing on the quality and myofibrillar protein-related properties of salmon (Salmo salar)

Multi-frequency ultrasound-assisted thawing (MUAT) has been proven to be an effective method of maintaining the quality of frozen food. The effects of magnetic nano-particles (MNPs) combined with MUAT and multi-frequency ultrasound-assisted sequential thawing (MUST) on water retention, myofibrillar protein (MP) structural characteristics, function characteristics, and MP aggregation and degradation of salmon (Salmo salar) were studied. The results showed that MNPs combined with multi-frequency ultrasound-assisted sequential thawing (MNPs-MUST) significantly improved the thawing rate and the retention of water and had better emulsifying and foaming properties. MNPs-MUST treatment reduced the oxidation and degradation of MP, increased sulfhydryl content, and protected the structure of MP. Confocal laser scanning microscopy (CLSM) indicated that the MP transformed into a filamentous polymer into more evenly distributed units, resulting in higher protein solubility, lower surface hydrophobicity, and lower protein turbidity. Therefore, MNPs combined with MUST has a potential application value in the thawing research of frozen salmon.

Influence of the liquid ionic strength on the resonance frequency and shell parameters of lipid-coated microbubbles

The correct measurement of the resonance frequency and shell properties of coated microbubbles (MBs) is essential in understanding and optimizing their response to ultrasound (US) exposure parameters. In diagnostic and therapeutic ultrasound, MBs are typically surrounded by blood; however, the influence of the medium charges on the MB resonance frequency has not been systematically studied using controlled measurements. This study aims to measure the medium charge interactions on MB behavior by measuring the frequency-dependent attenuation of the same size MBs in mediums with different charge densities. In-house lipid-coated MBs with C3F8 gas core were formulated. The MBs were isolated to a mean size of 2.35 μm using differential centrifugation. MBs were diluted to ≈8×105 MBs/mL in distilled water (DW), Phosphate-Buffered Saline solution (PBS1x) and PBS10x. The frequency-dependent attenuation of the MBs solutions was measured using an aligned pair of PVDF transducers with a center frequency of 10MHz and 100% bandwidth in the linear oscillation regime (7 kPa pressure amplitude). The MB shell properties were estimated by fitting the linear equation to experiments. Using a pendant drop tension meter, the surface tension at the equilibrium of ≈6 mm diameter size drops of the same MB shell was measured inside DW, PBS1x and PBS10x. The surface tension at the C3F8/solution interface was estimated by fitting the Young-Laplace equation from the recorded images. The frequency of the peak attenuation at different salinity levels was 13, 7.5 and 6.25 MHz in DW, PBS1x and PBS-10x, respectively. The attenuation peak increased by ≈140% with increasing ion density. MBs' estimated shell elasticity decreased by 64% between DW and PBS-1x and 36% between PBS-1x and PBS-10x. The drop surface tension reduced by 10.5% between DW and PBS-1x and by 5% between PBS-1x and PBS-10x, respectively. Reduction in the shell stiffness is consistent with the drop surface tension measurements. The shell viscosity was reduced by ≈40% between DW and PBS-1x and 42% between PBS-1x and PBS-10x. The reduction in the fitted stiffness and viscosity is possibly due to the formation of a densely charged layer around the shell, further reducing the effective surface tension on the MBs. The changes in the resonance frequency and estimated shell parameters were significant and may potentially help to better understand and explain bubble behavior in applications.

The Evolution of Sonochemistry: From the Beginnings to Novel Applications

Sonochemistry is the use of ultrasonic waves in an aqueous medium, to generate acoustic cavitation. In this context, sonochemistry emerged as a focal point over the past few decades, starting as a manageable process such as a cleaning technique. Now, it is found in a wide range of applications across various chemical, physical, and biological processes, creating opportunities for analysis between these processes. Sonochemistry is a powerful and eco-friendly technique often called "green chemistry" for less energy use, toxic reagents, and residues generation. It is increasing the number of applications achieved through the ultrasonic irradiation (USI) method. Sonochemistry has been established as a sustainable and cost-effective alternative compared to traditional industrial methods. It promotes scientific and social well-being, offering non-destructive advantages, including rapid processes, improved process efficiency, enhanced product quality, and, in some cases, the retention of key product characteristics. This versatile technology has significantly contributed to the food industry, materials technology, environmental remediation, and biological research. This review is created with enthusiasm and focus on shedding light on the manifold applications of sonochemistry. It delves into this technique's evolution and current applications in cleaning, environmental remediation, microfluidic, biological, and medical fields. The purpose is to show the physicochemical effects and characteristics of acoustic cavitation in different processes across various fields and to demonstrate the extending application reach of sonochemistry. Also to provide insights into the prospects of this versatile technique and demonstrating that sonochemistry is an adapting system able to generate more efficient products or processes.

Effect of ultrasound combined with pineapple protease treatment on the tenderness of dried shrimp

BACKGROUND

In order to improve the tenderness of dried shrimp products as well as to reduce the hardness of the meat during the drying process, shrimp were treated with ultrasound combined with pineapple protease and the tenderization condition was optimized by measuring the texture and shear force of dried shrimp. In addition, the sulfhydryl content, myofibril fragmentation index (MFI) and microstructure were also examined to clarify the mechanisms of shrimp tenderization.

RESULTS

The results showed UB1 group with ultrasonic power of 100 W, heating temperature of 50 °C and pineapple protease concentration of 20 U mL-1 were the optimum tenderization conditions, where shrimp showed the lowest hardness (490.76 g) and shear force (2006.35 gf). Microstructure as well as sodium dodecyl sulfate-polyacrylamide gel electrophoresis results suggested that during the tenderization process the muscle segments of shrimps were broken, degradation of myofibrillar proteins occurred, and MFI values and total sulfhydryl content increased significantly (P < 0.05) (MFI value = 193.6 and total sulfhydryl content = 93.93 mmol mg-1 protein for UB 1 group).

CONCLUSION

Ultrasound combined with bromelain could be used as a simple and effective tenderization method for the production of tender dried shrimp. The best conditions were 100 W ultrasonic power, 50 °C ultrasonic temperature, and 20 U mL-1 bromelain. © 2024 Society of Chemical Industry.

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.

Effect of different orthogonal double frequency ultrasonic assisted freezing on the quality of sea bass

The ice crystals formed in the body of the fish after freezing will cause irreversible damage to the fish's tissues, resulting in a decline in the fish quality. Therefore, based on the single frequency and double frequency ultrasonic freezing technology, the influence of orthogonal ultrasonic on the sea bass quality was studied. The results showed that the orthogonal ultrasonic wave could effectively improve the utilization rate of ultrasonic. In addition, SEM images showed that the muscle tissue in the dual frequency orthogonal ultrasonic assisted freezing group (DOUAF-40 (H) 20 (V)) was more uniform and dense. DOUAF-40 (H) 20 (V) group did not cause excessive oxidation of myofibrin on the one hand, and on the other hand reduced the duration of lipid oxidation in fish. The results showed that the orthogonal ultrasonic freezing technology inhibited the impact on fish quality during the freezing process, which provided a reference for the food freezing industry to improve aquatic products.

Progress in the application of novel cryoprotectants for the stabilization of myofibrillar proteins

In this review, the physicochemical and conformational changes of myofibrillar proteins (MPs) of freeze-induced mince-based aquatic foods were comprehensively summarized in depth. Studies have demonstrated that temperature fluctuation and long-time freezing negatively affect food quality, resulting in texture alteration, drip fluid, flavor degradation, and nutrition loss due to MPs denaturation, aggregation, and oxidation. Attempts have been made in ice-recrystallization inhibition, freezing point depression, and ice shape and growth control for better cryopreservation. Moreover, to further minimize the quality deterioration, cryoprotectants were acknowledged to reduce the denaturation and aggregation of the MPs effectively. Recently, interest in novel functional ingredients, including oligosaccharides, protein hydrolysates, and natural polyphenols demonstrated excellent cryoprotective effects while avoiding health concerns and undesirable flavor caused by traditional sugar-based or phosphates-based cryoprotectants. Therefore, the present review provides a systematic overview of these low molecular weight multifunctional substances with a particular sequence and highlights their underlying mechanism in the inhibition of ice recrystallization the stabilization of MPs.

Enhanced gelling properties of myofibrillar protein by ultrasound-assisted thermal-induced gelation process: Give an insight into the mechanism

Effects of the incorporation of ultrasound with varied intensities (0-800 W) into the thermal-induced gelation process on the gelling properties of myofibrillar protein (MP) were explored. In comparison with single heating, ultrasound-assisted heating (<600 W) led to significant increases in gel strength (up to 17.9%) and water holding capacity (up to 32.7%). Moreover, moderate ultrasound treatment was conducive to the fabrication of compact and homogenous gel networks with small pores, which could effectively impair the fluidity of water and allow redundant water to be entrapped within the gel network. Electrophoresis revealed that the incorporation of ultrasound into the gelation process facilitated more proteins to get involved in the development of gel network. With the intensified ultrasound power, α-helix in the gels lowered pronouncedly with a simultaneous increment of β-sheet, β-turn, and random coil. Furthermore, hydrophobic interactions and disulfide bonds were reinforced by the ultrasound treatment, which was in support of the construction of preeminent MP gels.

The positive contribution of ultrasound technology in muscle food key processing and its mechanism-a review

Traditional processing methods can no longer meet the demands of consumers for high-quality muscle food. As a green and non-thermal processing technology, ultrasound has the advantage of improving processing efficiency and reducing processing costs. Of these, the positive effect of power ultrasound in the processing of muscle foods is noticeable. Based on the action mechanism of ultrasound, the factors affecting the action of ultrasound are analyzed. On this basis, the effect of ultrasound technology on muscle food quality and its action mechanism and application status in processing operations (freezing-thawing, tenderization, marination, sterilization, drying, and extraction) is discussed. The transient and steady-state effects, mechanical effects, thermal effects, and chemical effects can have an impact on processing operations through complex correlations, such as improving the efficiency of mass and heat transfer. Ultrasound technology has been proven to be valuable in muscle food processing, but inappropriate ultrasound treatment can also have adverse effects on muscle foods. In the future, kinetic models are expected to be an effective tool for investigating the application effects of ultrasound in food processing. Additionally, the combination with other processing technologies can facilitate their intensive application on an industrial level to overcome the disadvantages of using ultrasound technology alone.