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

Effect of constant-current pulsed electric field thawing on proteins and water-holding capacity of frozen porcine longissimus muscle

This study explored the effect of constant-current pulsed electric field thawing (CC-T) on the proteins and water-holding capacity of pork. Fresh meat (FM), and frozen meat after constant-voltage thawing (CV-T), air thawing (AT) and water immersion thawing (WT) were considered as controls. The results indicated that CC-T had a higher thawing rate than conventional thawing during ice-crystal melting stage (-5 to -1 °C). It also showed a lower water migration and thawing loss, maintaining pH and shear force closer to FM. Meanwhile, CC-T decreased myoglobin oxidation, resulting in a favorable surface color. The results of protein solubility, differential scanning calorimetry, total sulfhydryl, carbonyl and surface hydrophobicity demonstrated that CC-T reduced myofibrillar protein oxidative denaturation by suppressing the formation of disulfide and carbonyl bonds, thus enhancing solubility and thermal stability. Additionally, microstructural observation found that CC-T maintained a relatively intact muscle fiber structure by reducing muscle damage and myosin filament denaturation.

Assessing Individual Muscle Characteristics to Enhance Frozen-Thawed Meat Quality

This study assessed previous research aimed at mitigating the adverse effects of freeze-thawing on meat quality. Specifically, it focuses on assessing the physicochemical alterations in meat resulting from freezing, freeze-thawing, or technologies to minimize these alterations. Recent studies have focused on conventional freeze-thaw technology applicable across various livestock species and muscle types. However, recent research has indicated the necessity for developing freeze-thaw technology considering the unique characteristics of individual muscles. In this review, we summarize previous studies that have compared alterations in the physicochemical properties of primary muscles owing to freezing or freeze-thawing. Despite the introduction of various technologies to significantly reduce the adverse effects on meat quality resulting from freeze-thawing, it is essential to consider the unique characteristics (proximate composition, pH, and muscle fiber characteristics) of individual muscles or cuts to develop enhanced the freeze-thaw processing technology.

Effects of different drying methods on physicochemical, textural, flavor, and sensory characteristics of yak jerky

The work aimed to study the effect of four drying methods, namely constant temperature hot air drying (HD), microwave drying (MD), hot air microwave drying (HMD), and gradient hot air drying (GHD), on quality characteristics of dried yak meat. The analyses of physicochemical, textural, flavor, and sensory characteristics were carried out based on these four drying methods. The results revealed that microwave dried yak jerky exhibited better color and received the highest sensory score. Hardness of samples were affected by the drying methods, which showed significant differences. There were 21 free amino acids (FAAs) detected in dried yak samples. The samples treated by microwave drying showed the highest total free amino acid content (73.30 mg/100 g) and the EUC value was significantly higher than other methods, indicating the sample displayed greater flavor. A total of 153 volatile compounds were identified in dried yak meat samples, primarily including aldehydes, ketones, and esters. Moreover, the sensory evaluation indicated that the drying methods could significantly affect on color, flavor, and overall acceptability of different samples. Microwave drying samples scored higher than other drying methods. Overall, considering aspects of quality, time savings, and energy efficiency, microwave drying of yak jerky emerges as a more satisfactory option. This study could provide important theoretical support for the application of drying methods to improve the quality of yak jerky and enhance production efficiency.

Polymorphisms of ITGA9 Gene and Their Correlation with Milk Quality Traits in Yak (Bos grunniens)

A single-nucleotide polymorphism (SNP) is a genome-level trait that arises from a variation in a single nucleotide, leading to diversity in DNA sequences. SNP screening is commonly used to provide candidate genes for yak breeding efforts. Integrin Subunit Alpha 9 (ITGA9) is an integrin protein. It plays an important role in cell adhesion, signalling, and other processes. The aim of this study was to discuss the association between genetic polymorphisms in the ITGA9 gene and milk quality traits and to identify potential molecular marker loci for yak breeding quality. We genotyped 162 yaks using an Illumina Yak cGPS 7K liquid chip and identified the presence of polymorphisms at nine SNP loci in the ITGA9 gene of yaks. The results showed that the mutant genotypes in the loci g.285,808T>A, g.306,600T>C, and g.315,413C>T were positively correlated with the contents of casein, protein, total solids (TS), and solid nonfat (SNF) in yak milk. In other loci, heterozygous genotypes had a positive correlation with nutrient content in yak milk. Then, two ITGA9 haplotype blocks were constructed based on linkage disequilibrium, which facilitated a more accurate screening of ITGA9 as a candidate gene for yak milk quality improvement. In conclusion, we identified SNPs and haplotype blocks related to yak milk quality traits and provided genetic resources for marker-assisted selection in yak breeding.

The Effects of Assisted Freezing with Different Ultrasound Power Rates on the Quality and Flavor of Braised Beef

This study investigated the effects of ultrasound-assisted immersion freezing (UIF) at different power rates (0, 200, 400, and 600 W) on the changes in beef quality and flavor after braising. The results demonstrated that UIF treatment at 400 W significantly reduced the juice loss (cooking loss decreased from 49.04% to 39.74%) and fat oxidation (TBARS value decreased from 0.32 mg/kg to 0.20 mg/kg) of braised beef. In addition, the tenderness (hardness value decreased from 5601.50 g to 2849.46 g) and color stability of braised beef were improved after UIF treatment. The flavor characteristics of braised beef were characterized using an electronic nose and an electronic tongue. The PCA analysis data showed that the cumulative contribution rates of the first and second principal components were 85% and 93.2%, respectively, with the first principal component accounting for a higher proportion. The UIF-400 W group had the highest concentration for the first principal component, and the differentiation was not significant compared to the control group. The total amino acid values of different power UIF treatment groups were improved compared to the AF treatment group, indicating that UIF can effectively reduce the losses caused by freezing. The results demonstrate that ultrasound-assisted freezing treatment is beneficial in enhancing the tenderness and flavor attributes of beef after braising, providing new insights into the processing of meat products with desirable quality characteristics.

Effect of static magnetic field-assisted thawing on the quality, water status, and myofibrillar protein characteristics of frozen beef steaks

This study investigated the effect of static magnetic field-assisted thawing (SMAT) at varying intensities (0, 1, 2, and 3 mT) on the quality, water status, and myofibrillar protein (MP) characteristics of frozen beef steaks. The thawing times of SMAT-1, 2, and 3 treatments could be shortened by approximately 10.9 %, 20.0 %, and 8.5 %, respectively, compared to the control. The results indicated that SMAT treatment significantly decreased thawing loss, maintained color stability, and reduced the degree of lipid oxidation in beef steaks compared to the control group (P < 0.05). Low-field nuclear magnetic resonance results confirmed that SMAT treatment enhanced the water-holding capacity of muscle. Furthermore, SMAT-2 treatment protected the muscle microstructure, decreased carbonyl content, and increased total sulfhydryl content (P < 0.05) compared to the control group. In conclusion, SMAT treatment effectively improved the beef quality and the characteristics of MP after thawing, especially in 2 mT.

Myosin heavy chain isoform expression and meat quality characteristics of different muscles in yak (Bos grunniens)

Myosin heavy chain (MHC) isoforms and meat quality characteristics of different muscles were investigated to explore their potential relationships in yaks. Results showed that semitendinosus (ST), longissimus thoracis (LT), and infraspinatus (IS) have a greater ratio of MHC IIb (47.84%), MHC IIa (73.27%), and MHC I (24.26%), respectively, than the other two muscles. Compared with LT or ST, IS exhibited more intense color, greater water-holding capacity, and initial tenderness with higher intermuscular fat (IMF) and collagen (of lower cross-linking level), presenting overall better quality. Variations in MHC isoforms accounted for the muscle-specific meat quality. Specifically, MHC I was positively associated with redness, myoglobin, IMF, collagen, pH, and thermal stability and negatively associated with myofibril fragmentation index, fiber thickness, collagen cross-linking, and drip loss. These results provide insights into the relationships between MHC isoforms and meat quality in yaks and the MHC I isoform has an extensive influence on meat quality.

Myofibril degradation and structural changes in myofibrillar proteins of porcine longissimus muscles during frozen storage

The effect of frozen time and the temperature on myofibril degradation and the structure of myofibrillar proteins of porcine longissimus muscles were investigated. With extended frozen time and increased temperature, the muscle fibres became broken; the muscle cells became irregularly arranged; and the fragmentation index value, number of ionic bonds, and number of hydrogen bonds of the samples significantly decreased. Meanwhile, the myofibril fragmentation index value, number of hydrophobic interactions, and number of disulphide bonds significantly increased (P < 0.05). After 12 months of storage, the intensities of I760/I1003, I850/I830, I1450/I1003, and I2945/I1003 in the samples frozen at -8 °C were reduced by 4.36 %, 1.28 %, 1.86 %, and 0.74 %, respectively. A reduction in the maximum absorption peak and a red shift were observed in the ultraviolet spectrum. Therefore, frozen storage resulted in significant damage to the tissue microstructureand caused accelerated protein degradation, and the loss of protein structural integrity.

Enhancing chicken breast meat quality through ultrasonication: Physicochemical, palatability, and amino acid profiles

Ultrasonication, a technology that employs high-frequency sound waves, has demonstrated potential for modifying the properties of various food items. However, the effect of ultrasonication on chicken meat, particularly concerning amino acid composition and flavor enhancement, has not been sufficiently investigated. The objective of this research was to bridge the gap in the literature by exploring the impact of various ultrasonic treatments at varying power levels (300, 500, and 800 W) and durations (10 and 30 min) on the physicochemical characteristics, texture, and amino acid profile of chicken breast meat, with a focus on improving its palatability and flavor. The results indicated that ultrasonication reduced the pH and cooking loss, as well as hardness and chewiness while simultaneously increasing lightness and yellowness values of chicken breast meat. Moreover, ultrasonication enhanced the amounts of essential amino acids, including glutamic acid, alanine, and glycine as well as the free amino acid content, which gives meat its savory and umami flavor. Furthermore, the results demonstrated significant changes in the texture and structure, as demonstrated by the scanning electron microscopy (SEM) images, and in chemical makeup of chicken breast meat, as indicated by the FTIR spectra. These modifications in the molecular and microstructural characteristics of meat, as induced by ultrasonication, may contribute to the enhancement of tenderness, juiciness, and overall palatability.

Improving the Flavour of Enzymatically Hydrolysed Beef Liquid by Sonication

Beef potentiator is an important flavour enhancer in the food industry, while it is prone to generating insufficient compounds with umami and sweet tastes and compounds with a fishy odour during enzymatic hydrolysis of beef, resulting in poor flavour of beef potentiator. It has been extensively reported that sonication is capable of improving food flavour. However, the effect of sonication on the flavour of enzymatically hydrolysed beef liquid (EHBL) was scarcely reported. Herein, we investigated the effect of sonication on the flavour of EHBL using quantitative descriptive analysis (QDA), physicochemical analysis and SPME-GC-olfactometry/MS. QDA showed that sonication had a significant effect on taste improvement and off-odour removal of EHBL. Compared with the control, sonication (40 kHz, 80 W/L) increased the contents of total nitrogen, formaldehyde nitrogen, total sugars, reducing sugars, free amino acids (FAAs) and hydrolysis degree of EHBL by 19.25%, 19.80%, 11.83%, 9.52%, 14.37% and 20.45%. Notably, sonication markedly enhanced the contents of sweet FAAs, umami FAAs and bitter FAAs of EHBL by 19.66%, 14.04% and 9.18%, respectively, which contributed to the taste improvement of EHBL. SPME-GC-olfactometry/MS analysis showed that aldehydes and alcohols were the main contributors to aroma compounds of EHBL, and sonication significantly increased the contents of key aroma compounds and alcohols (115.88%) in EHBL. Notably, sonication decreased the contents of fishy odorants, hexanoic acid and nonanal markedly by 35.29% and 26.03%, which was responsible for the aroma improvement of EHBL. Therefore, sonication could become a new potential tool to improve the flavour of EHBL.

Analysis of the suitable thawing endpoint of the frozen chicken breast using video recording analysis, shear force, and bioelectrical impedance measurement

This study focuses on analyzing the texture properties and bioelectrical impedance characteristics of frozen chicken breasts during low-temperature thawing, meanwhile, we also compared the differences in physiochemical properties. Frozen chicken breasts were thawed at 4 ± 2°C for 2, 4, 6, 8, and 10 h separately, then the physiochemical properties (color, pH, water-holding capacity, water distribution), the texture properties (easy-to-cut level), and the bioelectrical impedance were determined and analyzed. The easy-to-cut level of the samples was evaluated by the sensory panel and two indexes, one is Warner-Bratzler shear force measured by texture analysis machine, and the other is cutting speed value calculated by the consumer-oriented cutting behavior analysis using frame-by-frame video recording analysis method. These two methods were used to characterize the easy-to-cut level of the frozen samples during thawing from the industrial processing and home cooking standpoint. Strong correlations were observed between the easy-to-cut level and the bioelectrical impedance of the frozen chicken breasts during thawing. The impedance magnitude at 100 kHz showed a high correlation coefficient (R2  = .9417) with Warner-Bratzler shear force, and the impedance magnitude at 50 Hz showed a high correlation coefficient (R2  = .8658) with cutting speed. Our results indicated the acceptability of using bioelectrical impedance to evaluate the easy-to-cut thawing endpoint for both industry processing and home cooking.

The impact of freezing methods on the quality, moisture distribution, microstructure, and flavor profile of hand-grabbed mutton during long-term frozen storage

The aim of present study was to investigate the influence of conventional freezing (CF, -18 °C), low-temperaturefreezing (LF, -40 °C), and ultra-low-temperature freezing (ULF, -80 °C) on the quality, moisture distribution, microstructure, and flavor profile of hand-grabbed mutton (HGM) during frozen storage (0, 30, 60, 90, 120, 150 and 180 days). The TPC, TVB-N, and TBARS values increased significantly with prolonged storage, while the moisture content decreased (P < 0.05). Additionally, the concentrations of aldehydes, alcohols, ketones, acids, and alkenes decreased significantly as the storage duration increased. However, the concentrations of esters and heterocyclics increased (P < 0.05). Notably, at 30-180 days of storage, the TBARS and TVB-N values in ULF samples were significantly lower than those in CF and LF samples, while the moisture content was significantly higher (P < 0.05). Low field-nuclear magnetic resonance (LF-NMR) analysis showed that ULF decreased water migration and maintained the original texture characteristics of HGM during frozen storage. The ULF and LF groups had significantly higher levels of volatiles than the CF group (P < 0.05). The findings show that ULF, with its relatively rapid freezing rates, can still maintain the high quality of HGM after 180 days of frozen storage, contributing to quality control.

Challenges and processing strategies to produce high quality frozen meat

Freezing is an effective means to extend the shelf-life of meat products. However, freezing and thawing processes lead to physical (e.g., ice crystals formation and freezer burn) and biochemical changes (e.g., protein denaturation and lipid oxidation) in meat resulting in loss of quality. Over the last two decades, several attempts have been made to produce thawed meat with qualities similar to that of fresh meat to no avail. This is due to the fact that no single technique exists to date that can mitigate all the quality challenges caused by freezing and thawing. This is further confounded by the consumer perception of frozen meat as lower quality compared to equivalent fresh-never-frozen meat cuts. Therefore, it remains challenging for the meat industry to produce high quality frozen meat and increase consumer acceptability of frozen products. This review aimed to provide an overview of the applications of novel freezing and thawing technologies that could improve the quality of thawed meat including deep freezing, high pressure, radiofrequency, electro-magnetic resonance, electrostatic field, immersion solution, microwave, ohmic heating, and ultrasound. This review will also discuss the development in processing strategies such as optimising the ageing of meat pre- or post-freezing, and the integration of freezing and thawing in one process/regime to collapse the difference in quality between thawed meat and fresh-never-frozen equivalents.

The Sous Vide Cooking of Mediterranean Mussel (Mytilus galloprovincialis): Safety and Quality Assessment

This study involves an investigation of the effects of various cooking temperatures, freeze-thaw processes, and food preservatives on the quality and shelf-life of sous vide Mediterranean mussels. Cooking temperatures of 80 °C or above significantly improved the microbiological quality, with bacterial counts remaining within the acceptability range for human consumption even after 21 days of refrigerated storage. Fast freezing followed by slow thawing preserved the highest moisture content, potentially improving texture. Sensory analysis revealed that refrigerated sous vide mussels maintained a comparable taste to freshly cooked samples. Frozen samples reheated via microwaving exhibited more intense flavour than pan-reheated or fresh mussels. Food additives, including citric acid, potassium benzoate, and potassium sorbate, alone or in combination with grape seed oil, significantly reduced total volatile basic nitrogen and thiobarbituric acid-reactive substances during 28 days of storage, indicating decreased spoilage and lipid oxidation. Mussels with a combination of these additives registered a nitrogen content as low as 22 mg of N/100g after 28 days, well below the limit of acceptability (<35 mg of N/100g). Food additives also inhibited bacterial growth, with mesophilic bacteria count below 3.35 Log CFU/g after 28 days, compared with 5.37 Log CFU/g in control samples. This study provides valuable insights for developing optimal cooking and preservation methods for sous vide cooked seafood, underscoring the need for further research on optimal cooking and freeze-thaw protocols for various seafood types.

The combined effects of ultrasound and plasma-activated water on microbial inactivation and quality attributes of crayfish during refrigerated storage

In this study, a decontamination technology combining ultrasound (US) and plasma-activated water (PAW) was developed to better preserve crayfish. First, the decontamination efficacy of US, PAW and their combinations (UP) on crayfish was quantified after 0, 20, 40, or 60 min of treatments. The total viable count (TVC) was reduced by 0.27-0.77 Log CFU/g after individual US or PAW treatments, while a TVC reduction of 1.17 Log CFU/g was achieved after 40 min of UP treatment. Besides, the changes in psychrotrophic bacteria, lactic acid bacteria, yeasts and molds followed a similar trend to TVC. UP treatments normally resulted in more significant reductions in the natural microbiota of crayfish than US or PAW treatments. Furthermore, the microbial quality, physicochemical properties and sensory properties of crayfish after different treatments were assessed during storage at 4 °C for 12 days. According to TVC and total volatile basic nitrogen (TVB-N) values, the control group became unacceptable from 4 days, US or PAW groups became unacceptable from 6 days, while UP group extended the storage time to 8-10 days. During storage, thiobarbituric acid reactive substances (TBARS) values of all the groups were maintained below 0.5 mg/kg, among which the control group exhibited the highest value (0.39 mg/kg). Moreover, UP treatment effectively retarded the deterioration in color and texture properties of crayfish. Fourier transform infrared (FTIR) spectroscopy analysis indicated that UP treatment decreased the α-helix contents and increased the β-sheet contents of crayfish proteins, while the structural changes were not evident at the end of storage. Low-field nuclear magnetic resonance (LF-NMR) analysis revealed that UP treatment reduced the water migration and enhanced the stability of bond water in crayfish. In addition, E-nose analysis revealed the protection of UP treatment on the sensory properties of crayfish during storage. This study demonstrated that the combinations of US and PAW treatments effectively accelerated the decontamination of crayfish and contributed to better storage quality.

Physicochemical and structural changes of myofibrillar proteins in muscle foods during thawing: Occurrence, consequences, evidence, and implications

Myofibrillar protein (MP) endows muscle foods with texture and important functional properties, such as water-holding capacity (WHC) and emulsifying and gel-forming abilities. However, thawing deteriorates the physicochemical and structural properties of MPs, significantly affecting the WHC, texture, flavor, and nutritional value of muscle foods. Thawing-induced physicochemical and structural changes in MPs need further investigation and consideration in the scientific development of muscle foods. In this study, we reviewed the literature for the thawing effects on the physicochemical and structural characters of MPs to identify potential associations between MPs and the quality of muscle-based foods. Physicochemical and structural changes of MPs in muscle foods occur because of physical changes during thawing and microenvironmental changes, including heat transfer and phase transformation, moisture activation and migration, microbial activation, and alterations in pH and ionic strength. These changes are not only essential inducements for changes in spatial conformation, surface hydrophobicity, solubility, Ca2+ -ATPase activity, intermolecular interaction, gel properties, and emulsifying properties of MPs but also factors causing MP oxidation, characterized by thiols, carbonyl compounds, free amino groups, dityrosine content, cross-linking, and MP aggregates. Additionally, the WHC, texture, flavor, and nutritional value of muscle foods are closely related to MPs. This review encourages additional work to explore the potential of tempering techniques, as well as the synergistic effects of traditional and innovative thawing technologies, in reducing the oxidation and denaturation of MPs and maintaining the quality of muscle foods.

Slightly acidic electrolyzed water as a novel thawing media combined with ultrasound for improving thawed mutton quality, nutrients and microstructure

The effects of ultrasound-assisted slightly acidic electrolyzed water thawing (UET), air thawing (AT), water thawing (WT) and microwave thawing (MT) on the quality, nutrients and microstructure were investigated. The UET treatment did not affect the lightness (L*) but reduced the redness (a*) and yellowness (b*) of the mutton. The UET treatment could better maintain the textural properties. The UET group had a higher immobilized water and lower free water, which was closer to the state of the control group. The UET treatment not only effectively inhibited the lipid oxidation but also reduced the loss of nutrients, especially minerals. The microstructure of the UET group was smoother and more complete, and the muscle fibers did not show significant breakage. In conclusion, UET treatment could better maintain the quality, nutrients and microstructure of thawed mutton. Therefore, UET could be regarded as a potential thawing method for application in the processing of meat products.

Mono-frequency ultrasonic-assisted thawing of frozen goose meat: Influence on thawing efficiency, product quality and microstructure

This study aimed to investigate the influences of mono-ultrasound assisted thawing on the thawing efficiency, product quality and conformational characteristics of frozen goose meat. The thawing time, thawing loss, muscle quality, and microstructure of frozen goose meat were studied. The results displayed that ultrasonic-assisted thawing effectively reduced the thawing time by 45.37-57.58% compared with non-sonicated group, and significantly decreased the thawing loss. For the quality properties of goose meat tissue, ultrasound-assisted thawing with single-frequency of 50 kHz indicated a lower protein turbidity; meanwhile, hardness values were also significantly increased, and displayed a higher springiness, gumminess and chewiness of goose meat tissue. The microstructure analysis exhibited that the conformation of goose myofibrillar protein (MP) was modified following ultrasonic-assisted thawing, and became closer and more irregular. Therefore, ultrasound-assisted thawing treatments at 50 kHz mono-frequency (temperature 25℃) have a high potential application value in the thawing research of frozen goose meat, and lay a theoretical foundation for use in the meat process industries.

Effects of alternating electric field assisted freezing-thawing-aging sequence on longissimus dorsi muscle microstructure and protein characteristics

The current study investigates the influence of alternating electric field (AEF)-assisted freezing-thawing-aging sequence on the muscle microstructure and myofibrillar protein characteristics. Three treatments were used for longissimus dorsi (LD) muscle: only aging (OA), freezing-thawing-aging sequence (FA) and AEF-assisted freezing-thawing-aging sequence (EA). Compared with the FA and EA groups, the OA group showed considerably fewer cracks between muscle fibers and maintained the integrity of the Z-line as observed using scanning and transmission electron microscopy, respectively. Furthermore, the EA treatment effectively decreased myofibrillar fragmentation, myofibrillar protein aggregation, and protein oxidation, as shown by the myofibrillar fragmentation index, turbidity, and total sulfhydryl concentration. Analysis of surface hydrophobicity and the Fourier transform infrared, UV absorption, and fluorescence spectrums indicated that AEF minimized the alterations of protein secondary and tertiary structure alterations during aging after freezing.

Do ultrasound form spontaneously nitrous pigments in nitrite-free pork meat batter?

The effects of ultrasound (US) on myoglobin modification, nitrous pigment formation, color, and total and free sulfhydryl content in nitrite-free pork meat batter were assessed. Five treatments were elaborated: Control (without US); TUS10'12 and TUS20'12 (sonication at 25 kHz, at 12 °C for 10 and 20 min, respectively); TUS10'18 and TUS20'18 (sonication at 25 kHz, at 18 °C for 10 and 20 min, respectively). Sonication for 20 min at 12 °C increased OxyMb and DeoxyMb pigments while reducing MetMb levels. This US condition also yielded higher red color indices and lower yellow color indices. Moreover, TUS20'12 exhibited enhanced nitrous pigment formation and decreased FerrylMb and free sulfhydryl (SH) values, indicating reduced oxidation in OxyMb and DeoxyMb pigments. In conclusion, the findings demonstrate that US can impart a cured color to nitrite-free meat products.

Effect of slaughter age and postmortem aging time on tenderness and water-holding capacity of yak (Bos grunniens) longissimus thoracis muscle

The present study investigated the effect of slaughter age (2.43 ± 0.20, 4.15 ± 0.19, 6.62 ± 0.18, 10.59 ± 0.74 years) and postmortem aging time (1, 24, and 72 h) on the tenderness and water-holding capacity (WHC) of yak longissimus thoracis muscles to determine the most suitable age for slaughter to ensure product consistency. Under conventional postmortem aging conditions (4 °C), muscles of each age group exhibited the effect of cold shortening. Once the cold shortening occurred, the age effect on thickening muscle fiber and developing cross-links of collagen, considered to intensify the meat toughness, became less important. Owing to greater carcass weight and intramuscular fat, muscles of the older carcass (over 6-year-old) were less influenced by the cold shortening effect during the chilling process and showed lessened sarcomere contraction, delayed formation of drip loss channels, and increased level of myofibril fragmentation index (MFI) and myofiber structural disintegration, resulting in greater tenderness and WHC, especially 6-7 years group. Aging of 72 h structurally disintegrated the collagen cross-linking and integrity of muscle fibers and elevated the MFI, improving the meat tenderness. Therefore, the suitable slaughter age for yak is 6-7 years old and after 72 h aging, improved quality of yak meat can be obtained.

A novel infrared and microwave alternate thawing method for frozen pork: Effect on thawing rate and products quality

The effect of infrared and microwave alternate thawing (IR + MWT) on frozen pork were compared to fresh, air thawing (AT), infrared thawing (IRT), microwave thawing (MWT). The IR + MWT took only about 11.81 min of the thawing time compared to AT 66.5 min, and the Raman spectroscopy and Low-field nuclear magnetic resonance (LF-NMR) results showed that the IR + MWT maintained better protein secondary structure composition and moisture state compared to MWT and IRT. In terms of thawing losses, IR + MWT had the lowest loss 1.92%. In terms of texture, IR + MWT had the least effect on the post-thawing textural properties and increased the springiness of the meat. Scanning electron microscopy results also showed that there was reduced damage to the muscle structure with IR + MWT. Regarding the odor of the meat after thawing, IR + MWT retained the odor better and was closer to the fresh sample. Therefore, IR + MWT can be used to enhance the thawing rate to protect the quality of the thawed pork.

Application of physical field-assisted freezing and thawing to mitigate damage to frozen food

Freezing is an effective technique to prolong the storage life of food. However, the freeze-thaw process also brings challenges to the quality of food, such as mechanical damage and freeze cracks. Increasingly, physical fields have been preferred as a means of assisting the freezing and thawing (F/T) processes to improve the quality of frozen food because of their high efficiency and simplicity of application. This article systematically reviews the application of high-efficiency physical field techniques in the F/T of food. These include ultrasound, microwave, radio frequency, electric fields, magnetic fields, and high pressure. The mechanisms, application effects, advantages and disadvantages of these physical fields are discussed. To better understand the role of various physical fields, the damage to food caused by the F/T process and traditional freezing is discussed. The evidence shows that the physical fields of ultrasound, electric field and high pressure have positive effects on the F/T of food. Proper application can control the size and distribution of ice crystals effectively, shorten the freezing time, and maintain the quality of food. Microwave and radio frequency exhibit positive effects on the thawing of food. Dipole rotation and ion oscillation caused by electromagnetic waves can generate heat inside the product and accelerate thawing. The effects of magnetic field on F/T are controversial. Although some physical field techniques are effective in assisting F/T of food, negative phenomena such as uneven temperature distribution and local overheating often occur at the same time. The generation of hotspots during thawing can damage the product and limit application of these techniques in industry. © 2022 Society of Chemical Industry.

Effects of sous vide cooking combined with ultrasound pretreatment on physicochemical properties and microbial communities of Russian sturgeon meat (Acipenser gueldenstaedti)

BACKGROUND

The production of Russian sturgeon is expanding rapidly in China but it is necessary to adopt measures to extend the shelf life of sturgeon meat. Previous studies found that sous vide cooking (SVC) at 60 °C increased the protein and lipid oxidation. The addition of antioxidant substances reduced the acceptance of the product. The effect of combination SVC and ultrasound pretreatment was therefore investigated.

RESULTS

Results showed that SVC at 50 °C combined with ultrasound effectively restrained the growth of total viable counts (TVC) in samples. Meanwhile, the main dominant genera changed from Pseudomonas to Carnobacterium and the number of microbial species decreased. The odor profile of Russian sturgeon meat was more stable and the lipoxygenase (LOX) activity decreased more rapidly after treating with SVC and ultrasound. Importantly, more stable protein aggregates were formed in samples treated by SVC 50 °C together with ultrasound pretreatment, so the protein and lipid oxidation were slowed during storage. Higher springiness values were obtained and the color of sturgeon meat was lighter under these conditions.

CONCLUSION

The combination of SVC 50 °C and ultrasound pretreatment effectively inhibited the microbial growth of Russian sturgeon meat at lower oxidation levels. These findings theoretically support the preservation and development of sturgeon meat, and the application of SVC technology. © 2022 Society of Chemical Industry.

The Novel Structural Variation in the GHR Gene Is Associated with Growth Traits in Yaks (Bos grunniens)

The growth hormone receptor (GHR) is a member of the cytokine/hematopoietic factor receptor superfamily, which plays an important role in the growth and development, immunity, and metabolism of animals. This study identified a 246 bp deletion variant in the intronic region of the GHR gene, and three genotypes, including type II, type ID, and type DD, were observed. Genotype analysis of structural variation (SV) was performed on 585 individuals from 14 yak breeds, and it was found that 246 bp deletion was present in each breed. The II genotype was dominant in all yak breeds except for SB yak. The association analysis of gene polymorphisms and growth traits in the ASD yak population showed that the 246 bp SV was significantly associated with body length at 6 months (p < 0.05). GHR messenger RNA (mRNA) was expressed in all the tested tissues, with significantly higher levels in the liver, muscle, and fat than in other organs. The results of transcription activity showed that the luciferase activity of the pGL4.10-DD vector was significantly higher than that of the pGL4.10-II vector (p < 0.05). Additionally, the transcription-factor binding prediction results showed that the SV in the runt-related transcription factor 1 (Runx1) transcription-factor binding site may affect the transcriptional activity of the GHR gene, regulating yak growth and development. This study showed that the novel SV of the GHR gene could be used as a candidate molecular marker for the selection of the early growth trait in ASD yak.

Ultrasound combined with slightly acidic electrolyzed water thawing of mutton: Effects on physicochemical properties, oxidation and structure of myofibrillar protein

The effects of air thawing (AT), water immersion thawing (WT), microwave thawing (MT) and ultrasound combined with slightly acidic electrolyzed water thawing (UST) on the myofibrillar protein (MP) properties (surface hydrophobicity, solubility, turbidity, particle size and zeta potential), protein oxidation (carbonyl content and sulfhydryl content) and structure (primary, secondary and tertiary) of frozen mutton were investigated in comparison with fresh mutton (FM). The solubility and turbidity results showed that the MP properties were significantly improved in the UST treatment. UST treatment could effectively reduce the MP aggregation and enhance the stability, which was similar to the FM. In addition, UST treatment could effectively inhibit protein oxidation during thawing as well. The primary structure of MP was not damaged by the thawing methods. UST treatment could reduce the damage to MP secondary and tertiary structure during the thawing process compared to other thawing methods. Overall, the UST treatment had a positive influence in maintaining the MP properties by inhibiting protein oxidation and protecting protein structure.

A comprehensive review of the principles, key factors, application, and assessment of thawing technologies for muscle foods

For years, various thawing technologies based on pressure, ultrasound, electromagnetic energy, and electric field energy have been actively investigated to minimize the amount of drip and reduce the quality deterioration of muscle foods during thawing. However, existing thawing technologies have limitations in practical applications due to their high costs and technical defects. Therefore, key factors of thawing technologies must be comprehensively analyzed, and their effects must be systematically evaluated by the quality indexes of muscle foods. In this review, the principles and key factors of thawing techniques are discussed, with an emphasis on combinations of thawing technologies. Furthermore, the application effects of thawing technologies in muscle foods are systematically evaluated from the viewpoints of eating quality and microbial and chemical stability. Finally, the disadvantages of the existing thawing technologies and the development prospects of tempering technologies are highlighted. This review can be highly instrumental in achieving more ideal thawing goals.

Experiments and simulations demonstrating the rapid ultrasonic rewarming of frozen tissue cryovials

The development of methods to safely rewarm large cryopreserved biological samples remains a barrier to the widespread adoption of cryopreservation. Here, experiments and simulations were performed to demonstrate that ultrasound can increase rewarming rates relative to thermal conduction alone. An ultrasonic rewarming setup based on a custom 444 kHz tubular piezoelectric transducer was designed, characterized, and tested with 2 ml cryovials filled with frozen ground beef. Rewarming rates were characterized in the -20 °C to 5 °C range. Thermal conduction-based rewarming was compared to thermal conduction plus ultrasonic rewarming, demonstrating a tenfold increase in rewarming rate when ultrasound was applied. The maximum recorded rewarming rate with ultrasound was 57° C/min, approximately 2.5 times faster than with thermal conduction alone. Coupled acoustic and thermal simulations were developed and showed good agreement with the heating rates demonstrated experimentally and were also used to demonstrate spatial heating distributions with small (<3° C) temperature differentials throughout the sample when the sample was below 0° C. The experiments and simulations demonstrate the potential for ultrasonic cryovial rewarming with a possible application to large volume rewarming, as faster rewarming rates may improve the viability of cryopreserved tissues and reduce the time needed for cells to regain normal function.

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.

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

Solid foods include fish, shrimp, shellfish, and other aquatic products, fruits, and vegetables. These products are commonly used for food freezing, cooling, and thawing. However, traditional freezing, cooling, and thawing of solid food technologies have limitations in quality, such as protein denaturation and water loss in food. Ultrasound-assisted technology has become a useful method in solid food processing due to improved preservation quality of solid food. This paper comprehensively reviews the mechanism and application of ultrasonic in solid food processing technology. Although the application of ultrasound-assisted ultrasound in solid food processing is relatively comprehensive, the energy saving of food cold processing is essential for practical application. This paper analyzes the optimization of ultrasonic in solid food processing, including orthogonal/multi-frequency technology and the combination of ultrasonic and other technologies, which provides new ideas for freezing, cooling, and thawing of solid food processing.

Effects of ultrasound-assisted thawing on lamb meat quality and oxidative stability during refrigerated storage using non-targeted metabolomics

The aim of this study was to evaluate the changes of ultrasound-assisted thawing on lamb meat quality and differential metabolite profiles during refrigerated storage. Compared with flow water thawing (FW), pH, a*, C*, and sulfhydryl content of lamb were significantly increased, while L*, drip loss and cooking loss were significantly decreased after ultrasound-assisted thawing (UT). On day 1 (UT1 and FW1) and day 7 (UT7 and FW7) in the UT and FW groups, principal component analysis explained 42.22% and 39.25% of the total variance. In this study, 44 (UT1 and FW1) and 47 (UT7 and FW7) differentially expressed metabolites were identified, including amino acids, carbohydrates and their conjugates, nucleic acids, carbonyl compounds and others. The results of this study provide data to clarify the differences between UT and FW, and lay a foundation for the application of ultrasound-assisted thawing in the meat industry.

Research progress on quality deterioration mechanism and control technology of frozen muscle foods

Freezing can prolong the shelf life of muscle foods and is widely used in their preservation. However, inevitable quality deterioration can occur during freezing, frozen storage, and thawing. This review explores the eating quality deterioration characteristics (color, water holding capacity, tenderness, and flavor) and mechanisms (irregular ice crystals, oxidation, and hydrolysis of lipids and proteins) of frozen muscle foods. It also summarizes and classifies the novel physical-field-assisted-freezing technologies (high-pressure, ultrasound, and electromagnetic) and bioactive antifreeze (ice nucleation proteins, antifreeze proteins, natural deep eutectic solvents, carbohydrate, polyphenol, phosphate, and protein hydrolysates), regulating the dynamic process from water to ice. Moreover, some novel thermal and nonthermal thawing technologies to resolve the loss of water and nutrients caused by traditional thawing methods were also reviewed. We concluded that the physical damage caused by ice crystals was the primary reason for the deterioration in eating quality, and these novel techniques promoted the eating quality of frozen muscle foods under proper conditions, including appropriate parameters (power, time, and intermittent mode mentioned in ultrasound-assisted techniques; pressure involved in high-pressure-assisted techniques; and field strength involved in electromagnetic-assisted techniques) and the amounts of bioactive antifreeze. To obtain better quality frozen muscle foods, more efficient technologies and substances must be developed. The synergy of novel freezing/thawing technology may be more effective than individual applications. This knowledge may help improve the eating quality of frozen muscle foods.

Effects of Alternating Electric Field Assisted Freezing-Thawing-Aging Sequence on Data-Independent Acquisition Quantitative Proteomics of Longissimus dorsi Muscle

This study was designed to investigate the differences in the proteomes of bovine Longissimus dorsi (LD) muscle during an alternating electric field (AEF)-assisted freezing-thawing-aging sequence based on a data-independent acquisition strategy. When compared to that of the only postmortem aging (OA) group, the meat quality of the freezing-thawing-aging sequence (FA) and AEF-assisted freezing-thawing-aging sequence (EA) groups showed a declining trend. However, the group assisted by AEF was significantly enhanced in color, water-holding capacity, and tenderness. Three hundred fifty-two proteins in LD muscle were differentially abundant proteins (DAPs) among FA, EA, and OA treatments. Furthermore, among the 40 DAPs in the FA versus EA comparison, 5 DAPs with variable importance in projection scores higher than 1 were identified as biochemical markers of beef quality. Bioinformatic analysis revealed that most of these proteins were involved in structural constituents of ribosome and catalytic activity. These results provide a basis for further understanding the quality of beef following a freezing-thawing-aging sequence assisted by AEF.

Impact of ultrasonication applications on color profile of foods

Food color is a feature that provides preliminary information about their preference or consumption. There are dominant pigments that determine the color of each food; the most important pigments are anthocyanins (red-purple color), chlorophylls (green color), carotenoids (yellow-orange color), and betalains (red color). These pigments can be easily affected by temperature, light, oxygen, or pH, thereby altering their properties. Therefore, while processing, it is necessary to prevent the deterioration of these pigments to the maximum possible extent. Ultrasonication, which is one of the emerging non-thermal methods, has multidimensional applications in the food industry. The present review collates information on various aspects of ultrasonication technology, its mechanism of action, influencing factors, and the competence of different ultrasonication applications (drying, irradiation, extraction, pasteurization, cooking, tempering, etc.) in preserving the color of food. It was concluded that ultrasonication treatments provide low-temperature processing at a short time, which positively influences the color properties. However, selecting optimum ultrasonic processing conditions (frequency, power, time, etc.) is crucial for each food to obtain the best color. The key challenges and limitations of the technique and possible future applications are also covered in the paper, serving as a touchstone for further research in this area.

Study on the quality and myofibrillar protein structure of chicken breasts during thawing of ultrasound-assisted slightly acidic electrolyzed water (SAEW)

The effects of air thawing (AT), water thawing (WT), slightly acidic electrolyzed water (ET), ultrasound-assisted water thawing (WUT) and ultrasound-assisted slightly acidic electrolyzed water (EUT) on the quality and myofibrillar protein (MP) structure of chicken breasts were investigated. The results showed that WUT and EUT could significantly improve the thawing rate compared with AT, WT, and ET groups. The EUT group not only had lower thawing loss, but also their immobilized and free water contents were similar to fresh sample according to the low-field nuclear magnetic resonance (LF NMR) results. The EUT treatment had no adverse effect on the primary structure of the protein. The secondary and tertiary structures of MP were more stable in the EUT group according to Raman and fluorescence spectra. The muscle fibers microstructure from EUT group was neater and more compact compared with other thawing methods. Therefore, EUT treatment could be considered as a novel potential thawing method in the food industry.

Application of infrared and microwave heating prior to freezing of pork: Effect on frozen meat quality

The effect of thermal treatment using infrared and microwave fields on freezing of pork loin was investigated. Several infrared and microwave treatment protocols were designed and tested to determine the thawing losses is each case to identify the most suitable one which yielded the best quality. In addition, the state of moisture in the meat, cooking loss, texture, color, pH, Thiobarbituric acid-reactive substances (TBARS), and other indicators were also evaluated. The results show that both microwave and infrared pre-dehydration can reduce the thawing loss of pork loin; the minimum loss is only about 1.7% using microwave 50 W intensity of 1.92 W/g of wet pork. Pre-dehydration also reduced the hardness of all samples and increased springiness, cohesiveness, and resilience. It is noteworthy that pretreatment did not damage the color. Based on the results of this study it is concluded that thermal pretreatment using microwave or infrared fields of appropriate strength prior to freezing can yield good quality frozen pork meat.

Effect of Static Magnetic Field Assisted Thawing on Physicochemical Quality and Microstructure of Frozen Beef Tenderloin

Although freezing is the most common and widespread way to preserve food for a long time, the accumulation of microstructural damage caused by ice crystal formation during freezing and recrystallization phenomena during thawing tends to degrade the quality of the product. Thus, the side effects of the above processes should be avoided as much as possible. To evaluate the effect of different magnetic field strength assisted thawing (MAT) on beef quality, the indicators associated with quality of MAT-treated (10-50 Gs) samples and samples thawed without an external magnetic field were compared. Results indicated that the thawing time was reduced by 21.5-40% after applying MAT. Meat quality results demonstrated that at appropriate magnetic field strengths thawing loss, TBARS values, cooking loss, and shear force were significantly decreased. Moreover, by protecting the microstructure of the muscle, MAT significantly increased the a∗ value and protein content. MAT treatment significantly improved the thawing efficiency and quality of frozen beef, indicating its promising application in frozen meat thawing.

Modification of the vacuum-steam thawing method of meat by using the initial stage of sublimation dehydration

Vacuum-steam thawing is one of the methods used for defrosting food, realized in the atmosphere of water vapour under the conditions of reduced pressure. The water vapour formed in vacuum with the temperature of 20 °C fills the defrosting chamber and condenses on the surface of the defrosted product. The condensated steam has the role of thermal energy carried enabling product thawing. The study presents a modification of this method, introducing an additional stage of sublimation-dehydration vacuum steam thawing (SRVST). The study was carried out for different variants of initial sublimation degree (in the range from 0 to 15%) of a slice of pork loin (m. longissimus lumborum) assessing the final effect of the process of vacuum-steam thawing. Thawing kinetics was determined with the SRVST method, degree of sample defrosting and level of their rehydration. Based on the results it was demonstrated that the use of 12% sublimation dehydration of a meat sample enables its complete defrosting (reaching the temperature not exceeding the cryoscopic temperature).

Study on the Flavor Compounds of Fo Tiao Qiang under Different Thawing Methods Based on GC–IMS and Electronic Tongue Technology

“Fo Tiao Qiang” is a famous dish with Chinese characteristics. It is delicious, rich in materials, and high in nutritional value. Through physical and chemical analysis, electronic tongue, gas chromatography–ion mobility spectroscopy, and other technologies, the present study explored the quality characteristics and flavor differences of Fo Tiao Qiang by using different thawing methods (natural thawing, ultrasonic thawing, microwave thawing, and water bath thawing). The results show that the protein content was slightly higher in Fo Tiao Qiang with ultrasonic thawing than others. The fat content of the microwave-thawed Fo Tiao Qiang was significantly lower than the other three kinds of samples. After ultrasonic thawing, the number of free amino acids in the samples were the highest and the umami taste was the best. Compared with natural thawing, most of the flavor substances decreased in ultrasonic thawing, microwave thawing, and water bath thawing. However, several substances increased, such as alpha-terpineol, beta-phenylethyl alcohol, phenylacetaldehyde, cis-rose oxide, isobutyl acetate, and 2–3-pentanedione. This study revealed the changing laws of different thawing methods on the quality characteristics and flavor characteristics of Fo Tiao Qiang. It provides theoretical guidance for the industrial production and quality control of Fo Tiao Qiang.

Power ultrasound in the meat industry (freezing, cooking and fermentation): Mechanisms, advances and challenges

High intensity ultrasound (HIUS) has a wide range of applications in different sectors of food processing. It is a promising and emerging technology demonstrating the potential to promote food processes without or at least damage to the quality of products. Among the processes of the meat industry, freezing, thawing, cooking and fermentation are very sensitive and important, because they have significant effects on product quality and are also very energy and time consuming. This review paper provides an interpretation of high intensity ultrasound (HIUS) applications, a summary of recent outstanding published research and an overview of the freezing/thawing, cooking/frying and fermentation processes in meat and its products assisted by HIUS. The effects, benefits and drawbacks as well as the challenges ahead in the commercialization of this technology in the meat industry are studied. The research results confirmed that the use of HIUS in the meat freezing/thawing, cooking/frying and fermentation in combination with the corresponding processing methods demonstrates a great potential to promote the process, improve the general quality of the final product and reduce the time and energy required. However, many issues remain that require further research to address these challenges. These challenges and subsequent research that is useful for developing and increasing the efficiency of this technology have been reviewed. After the literature review, it is concluded that HIUS may be a useful technology for meat processing because of its significant effects on the quality factors and related process variables that leads to the preservation of the initial nutritional and sensory properties of meat and its products. Of course, research must be continued to eliminate the disadvantages or minimize the undesirable effects of this technology on the final product and to remove barriers to commercialization and optimization of this method.

Impact of Ultrasound-assisted Saline Thawing on the Technological Properties of mirror carp (Cyprinus carpio L.)

The aim of the study was to evaluate the positive effect of ultrasound-assisted saline thawing (UST) on the technological properties (water mobility, water holding capacity, colour, pH, shear force, TVB-N, oxidation reaction and microstructure) of mirror carp (Cyprinus carpio L.). The results present in the study showed that different thawing methods had negative impacts on the quality of mirror carp to varying degrees. Among them, UST samples had significant lower thawing loss, centrifugal loss and cooking loss than ultrasound thawing (UT) and air thawing (AT) samples (P < 0.05). The analysis result of low-field nuclear magnetic resonance illustrated that UST inhibited the mobility and distribution of water effectively. Decrease in shear force and TVBN values were observed in all thawing samples, and the UST samples maintained the significant better texture property and freshness than UT and AT samples did (P < 0.05). In addition, the treatment of UST obtained 1% salt concentration inhibited the oxidation reactions effectively. Investigation of the microstructure of samples demonstrated that the treatment of UST kept the relatively complete structure of tissue than other thawing methods. Therefore, UST can be an alternative strategy to the traditional thawing of meat.