Effects of power ultrasound on oxidation and structure of beef proteins during curing processing

Effects of the structure and gel properties of myofibrillar protein on chicken breast quality treated with ultrasound-assisted potassium alginate

This paper aimed to evaluate the effects of the structure and gel properties of myofibrillar protein (MP) on 300-days-old chicken breast quality treated with ultrasound (300 W) and low addition (4 mg/mL) of potassium alginate (UPA). The results showed that UPA group exhibited lower liquid loss and optimized texture correlated with the formed water barrier and damaged myofibrils. UPA reduced the MP size and increased its solubility, and the decreased myosin thermostability and dissociated actomyosin reduced heating time for improved texture. UPA improved the gel strength, elastic modulus and ordered-arrangement of network. During gelation, the aggregation of myosin head was weakened and cross-linking of myosin tail and PA molecules was enhanced by hydrophobic interactions. UPA further inhibited the formation of disulfide bonds of myosin head and increased gel firmness. The lower myosin gelling temperature thus accelerated gel formation, and enhanced protein association with PA molecules facilitated the better gel performance.

Extraction of protein from food waste: An overview of current status and opportunities

The chief intent of this review is to explain the different extraction techniques and efficiencies for the recovery of protein from food waste (FW) sources. Although FW is not a new concept, increasing concerns about chronic hunger, nutritional deficiency, food security, and sustainability have intensified attention on alternative and sustainable sources of protein for food and feed. Initiatives to extract and utilize protein from FW on a commercial scale have been undertaken, mainly in the developed countries, but they remain largely underutilized and generally suited for low-quality products. The current analysis reveals the extraction of protein from FW is a many-sided (complex) issue, and that identifies for a stronger and extensive integration of diverse extraction perspectives, focusing on nutritional quality, yield, and functionality of the isolated protein as a valued recycled ingredient.

Effects of ultrasonic-assisted cooking on the volatile compounds, oxidative stability, and sensory quality of mortadella

Ultrasound is a form of green technology that has been applied efficiently to improve processes in the food industry. This study evaluated the application of ultrasound to reduce the cooking time of mortadella. The volatile compounds, oxidative stability, and sensory quality of mortadella were evaluated. Four cooking conditions were used, as follows: Control, corresponding to the cooking time traditionally used in the meat industry; TUS100 and TUS50: cooking with US (25 kHz) and 50% reduction of the cooking time of Control, using 100% (462 W) and 50% (301 W) amplitude, respectively; and TWUS: cooking without the application of US and 50% reduction of the cooking time of Control. TUS100 and TUS50 showed an increase of 10.8% and 29.4%, respectively, in the total amount of terpenes on the first day of storage in relation to the Control. The presence of nonane on the 60th day only in the US-treated samples (0.22 × 10⁶ vs 0.11 × 10⁶ for TUS100 and TUS50, respectively) indicated that the US treatment may have induced higher oxidation in mortadella. The oxidative stability index ranged from 274 to 369 days for TUS100 and the Control, respectively. The treatments TWUS and TUS50 showed a lower sensory quality at the end of storage. On the other hand, TUS100 presented sensory quality similar to the Control, demonstrating that ultrasonic-assisted cooking using a 100% amplitude is an alternative to reduce the cooking time without affecting the product quality.

Effects of combined ultrasound and low-temperature short-time heating pretreatment on proteases inactivation and textural quality of meat of yellow-feathered chickens

This study aimed to investigate the effect of combined ultrasound and low-temperature short-time heating (ULTSTH) (40 kHz, 0.2 W/cm² at 55 °C for 15 min) as pretreatment on proteases inactivation and textural quality of yellow-feathered chicken (YFC). Results showed ultrasound and low-temperature heating synergistically improved the inactivation of the most important meat proteases, calpain, cathepsin B and total proteases, with kinetics following the first order decay(s). Degradation of meat proteins was effectively reduced by ULTSTH compared to the pretreatment of chilling. Importantly, ULTSTH increased the firmness of breast meat and led to improved texture and microstructure. Lipid and protein oxidation of meat pretreated with ULTSTH were reduced during refrigerated storage period. Additionally, microorganisms in meat were inactivated by ULTSTH, which resulted in an obvious increase in the shelf life of meat. These findings suggested that ULTSTH is promising as an alternative pretreatment to obtain a favorable textural quality of YFC.

Stability improvement of reduced-fat reduced-salt meat batter through modulation of secondary and tertiary protein structures by means of high pressure processing

This study investigated the effect of high-pressure processing (HPP) at 100 to 400 MPa for 2 min on the stability of reduced-fat reduced-salt (RFRS) meat batter. Total expressible fluid (TEF) of RFRS batter reached its minimum value at 200 MPa. The results of Raman spectra revealed that α-helix reached its random coils increased as the pressure level was increased, and pressure up to 200 MPa remarkably increased protein unfolding but 400 MPa increased aggregation. Finally, Raman spectra and magnetic resonance imaging (MRI) revealed that 200 MPa significantly increased tryptophan, tyrosine doublet, CH₃ and/or CH stretching and proton intensities related to water and fats; but decreased β structures, SS stretching (475) and (g-g-t or t-g-t, 540), as compared with the control. RFRS batter treated at 200 MPa is beneficial for the meat industry from the technological point of view and for consumers from the health point of view, as the improved emulsion stability contributed by the modified secondary and tertiary structures.

Ultrasonic Freezing Reduces Protein Oxidation and Myofibrillar Gel Quality Loss of Common Carp (Cyprinus carpio) during Long-Time Frozen Storage

Ultrasonic freezing (UF) is an effective method to increase the freezing speed and improve the quality of frozen food. The effect of UF on myofibrillar protein oxidation and gel properties of common carp (Cyprinus carpio) during frozen storage were investigated with air freezing (AF) and immersion freezing (IF) as controls. The results showed that the carbonyl and dityrosine content of UF samples were lower and the free amine content was higher than those of AF and IF samples during frozen storage indicating that UF inhibited protein oxidation caused by frozen storage. The particle size of UF myofibrillar protein was the smallest among all the groups indicating that UF inhibited the protein aggregation. The UF sample had higher G', G" value, gel strength and gel water holding capacity than AF and IF groups showing that UF reduced the loss of protein gel properties. The gel microstructure showed that UF protein gel was characterized by smaller and finer pores than other samples, which further proves that UF inhibited loss of gel properties during frozen storage. The UF sample had shorter T2 transition time than other samples demonstrating that UF decreased the mobility of water. In general, UF is an effective method to reduce protein oxidation and gel properties loss caused by frozen storage.

Effect of ultrasound-assisted alkaline treatment on functional property modifications of faba bean protein

This study investigated alkaline shifting, ultrasonication, and their combination on functional modifications of faba bean protein isolate (FPI). The protein characterization revealed that the combined alkaline shifting/ultrasound treatment dissociated large aggregates of FPI into small ones, resulting in increased protein surface hydrophobicity and decreased free sulfhydryl groups. Such structural changes significantly increased FPI solubility from 12.2 to 40.4% to more than 95% at pH 3 and 7 and more than 80% at pH 6. Furthermore, the FPI modified by the combined alkaline shifting/ultrasound treatment produced emulsions with smaller particle size and superior stability at pH values 3 and 7. Likewise, a striking enhancement in foaming capacity (from 93% to 306-386%) and stability (from 10 s to 473-974 s) was achieved by the combined treatment. This study suggested that the ultrasound-assisted alkaline shifting treatment could be considered an effective method for improving FPI functional properties.

Application of temperature-controlled ultrasound treatment and its potential to reduce phosphate content in frankfurter-type sausages by 50

The objective of this study was to evaluate the effect of ultrasound treatments with different durations (15, 20, 25, 30, and 35 min) at a low static temperature (12 °C) controlled by an intelligent temperature control and monitoring system on the quality of 50% reduced-phosphate frankfurters. The results show that without ultrasound treatment, phosphate reduction caused some obvious deficits in the textural properties, sensorial parameters, and oxidative stability of frankfurters. Moreover, 25-min ultrasound treatment could significantly lower the cooking loss and enhance emulsion stability, textural properties, and sensorial parameters of reduced phosphate frankfurters, which was also verified by dynamic water distribution analysis and microstructural observation. Additionally, low constant temperature during ultrasound treatment was another crucial factor in retarding lipid oxidation during storage. Therefore, ultrasound treatment with moderate duration and stable low temperature could be considered a successful approach to obtain healthier reduced-phosphate frankfurters under the "clean label" concept.

High-intensity ultrasound improves threadfin bream surimi gelation at low NaCl contents

Effects of high-intensity ultrasound (HIU) treatments on gelation of threadfin bream (Nemipterus spp.) surimi at various NaCl contents (0.5, 1, and 2% NaCl) were investigated. Protein extractability at 0.5% NaCl was increased with the ultrasonic intensity (p < 0.05). At all tested NaCl contents, reactive sulfhydryl group (SH) content and surface hydrophobicity of the surimi pastes were increased after HIU treatments and were accompanied by a decrease in the Ca²⁺ -ATPase activity and total SH content, indicating a greater extent of unfolding and conformational changes induced by HIU at higher NaCl contents. Textural properties and color of the surimi gels at 0.5% NaCl were improved concomitant to an increase in ultrasonic intensity (p < 0.05), whereas HIU treatments resulted in inferior gels at 1 and 2% NaCl. Scanning electron microscopy (SEM) revealed that HIU resulted in a more orderly gel network at 0.5% NaCl. Fourier transform infrared (FT-IR) spectroscopy indicated that the α-helix content of the surimi gels was decreased as the ultrasonic intensity and NaCl content increased, confirming that structural changes induced by HIU were more profound at higher NaCl contents. The results suggested that HIU technology can be applied to improve only the 0.5% NaCl surimi gel. PRACTICAL APPLICATION: High-intensity ultrasound (HIU) improved surimi gel containing 0.5% NaCl due to an increase in protein extractability and protein conformational changes. It is likely to lay a theoretical foundation for utilization of HIU technology in production of surimi-based products at low/reduced salt levels.

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.

Insights into Digestibility and Peptide Profiling of Beef Muscle Proteins with Different Cooking Methods

This study aimed to investigate theeffects of sous vide (SV), boiling (BO), and roasting (RO) on beef protein digestibility and peptide profiling in simulated gastrointestinal digestion. The results indicated that beef samples treated with SV had higher (p < 0.05) gastrointestinal digestibility (34.97%) than those treated with BO (27.59%) and RO (24.36%). Furthermore, SV (2450) resulted in more types of peptides released during gastrointestinal digestion than BO (2077) and RO (1896) and a higher proportion of 400-1200 Da peptides. The significant increase of carbonyl content, the decrease of sulfhydryl content, and the formation of covalent bonds coupled with the transformation of protein secondary structure from α-helix to β-sheet suggested that excessive protein oxidation and aggregation occurred in BO and RO samples. These changes in BO and RO samples might explain the decreased protein digestibility and peptide release in gastrointestinal digestion. Thus, SV is a promising cooking method to improve beef protein digestibility.

Effect of ultrasound on proteolysis and the formation of volatile compounds in dry fermented sausages

Ultrasound (US) is an emerging technology capable of affecting enzymes and microorganisms, leading to the release of amino acids and the formation of volatile compounds. The effect of different exposure times (0, 3, 6, and 9 min) of US (25 kHz, 128 W) on the proteolysis and volatile compounds of dry fermented sausages during processing (day 0 and 28) and storage (day 1 and 120) was investigated. Lower alanine, glycine, valine, leucine, proline, methionine, and tyrosine levels were observed at the beginning of manufacture for the sample subjected to 9 min of US (p < 0.05) when compared to the control. During the storage period, the samples subjected to US exposure for 3 and 6 min exhibited higher free amino acid levels. A greater formation of hexanal, pentanal, and hexanol was observed in the US-treated samples when compared to the control (p < 0.05), as well as other derivatives from the oxidation reactions during the storage. The use of US (25 kHz and 128 W) in the manufacture of dry fermented sausages can affect the proteolysis and the formation of compounds derived from lipid oxidation during the storage.

Monitoring Thermal and Non-Thermal Treatments during Processing of Muscle Foods: A Comprehensive Review of Recent Technological Advances

Muscle food products play a vital role in human nutrition due to their sensory quality and high nutritional value. One well-known challenge of such products is the high perishability and limited shelf life unless suitable preservation or processing techniques are applied. Thermal processing is one of the well-established treatments that has been most commonly used in order to prepare food and ensure its safety. However, the application of inappropriate or severe thermal treatments may lead to undesirable changes in the sensory and nutritional quality of heat-processed products, and especially so for foods that are sensitive to thermal treatments, such as fish and meat and their products. In recent years, novel thermal treatments (e.g., ohmic heating, microwave) and non-thermal processing (e.g., high pressure, cold plasma) have emerged and proved to cause less damage to the quality of treated products than do conventional techniques. Several traditional assessment approaches have been extensively applied in order to evaluate and monitor changes in quality resulting from the use of thermal and non-thermal processing methods. Recent advances, nonetheless, have shown tremendous potential of various emerging analytical methods. Among these, spectroscopic techniques have received considerable attention due to many favorable features compared to conventional analysis methods. This review paper will provide an updated overview of both processing (thermal and non-thermal) and analytical techniques (traditional methods and spectroscopic ones). The opportunities and limitations will be discussed and possible directions for future research studies and applications will be suggested.

Duck breast muscle proteins, free fatty acids and volatile compounds as affected by curing methods

The aim of this study was to investigate the effects of different curing methods on protein structure, protein and lipid oxidation, lypolysis and volatile compounds in duck breast meat. The results showed that compared to static brining and pulsed pressure salting, the vacuum tumbling curing significantly decreased the oxidation of proteins and lipids, and the surface hydrophobicity of proteins, increased α-helix structure but decreased the proportion of β-sheet, and increased actomyosin dissociation, liplysis and the free fatty acid content in meat. Meanwhile, vacuum tumbling curing decreased the amount of volatile flavor compounds, hexanal, 2,3-octanone, and off-flavor compounds 1-octen-3-ol and 1-hexanol. This study suggests that concerns on healthiness and the sensory quality of processed meat products should be paid in the selection of curing methods and vacuum tumbling curing is superior in terms of both aspects.

Low-frequency and high-power ultrasound-assisted production of natural blue colorant from the milk and unripe Genipa americana L

This study presents the production of a novel natural blue colorant obtained from the cross-linking between milk proteins and genipin assisted by low-frequency and high-power ultrasound technology. Genipin was extracted from unripe Genipa americana L. using milk as a solvent. Also, milk colloidal system was used as a reaction medium and carrier for the blue color compounds. The effects of ultrasound nominal power (100, 200, 300, and 400 W) on the blue color formation kinetics in milk samples were evaluated at 2, 24, and 48 h of cold storage in relation to their free-genipin content and color parameters. In addition, Fourier transform infrared (FTIR) spectrum, droplet size distribution, microstructure, and kinetic stability of the blue colorant-loaded milk samples were assessed. Our results have demonstrated that the ultrasound technology was a promising and efficient technique to obtain blue colorant-loaded milk samples. One-step acoustic cavitation assisted the genipin extraction and its diffusion into the milk colloidal system favoring its cross-linking with milk proteins. Ultrasound process intensification by increasing the nominal power promoted higher genipin recovery resulting in bluer milk samples. However, the application of high temperatures associated with intensified acoustic cavitation processing favored the occurrence of non-enzymatic browning due to the formation of complex melanin substances from the Maillard reaction. Also, the blue milk samples were chemically stable since their functional groups were not modified after ultrasound processing. Likewise, all blue colorant-loaded milk samples were kinetically stable during their cold storage. Therefore, a novel natural blue colorant with high-potential application in food products like ice creams, dairy beverages, bakery products, and candies was produced.

Efficacy of Ultrasonic-Assisted Curing Is Dependent on Muscle Size and Ultrasonication System

Ultrasound-assisted marinade is a promising technology for reducing the time of traditional immersion marination. This study evaluated the effect of the ultrasonic system (bath or probe, amplitude 50 or 100%) and muscle sample size (3 or 5 cm3) on physicochemical quality, yield (salt content, fresh weight, and relative fresh weight), and bacteria counts associated with pork. The results showed a significantly high salt (p < 0.0001) content in 3 cm3 (11.54%) and 5 cm3 (8.88%) samples after 24 h marination by immersion. The 3 cm3 cubes marinated in a 100% probe system for 20 min presented an amount of salt (9.55%) that was quite close to the controls. The 3 cm3 samples treated by immersion and in a 50% probe system gained more relative weight (in relation to the initial weight, 7.45 and 6.64%, respectively) after 7 d at 4 °C. Meanwhile the 5 cm3 cubes marinated by immersion gained 8.1%. The other treatments showed a weight loss after treatment. Although significant differences were found in the fresh weight and in water holding capacity (WHC) in the 3 and 5 cm3 meat samples, the relative fresh weight is a real measure of weight gain, more relevant for the industry. Thus, the samples with the highest salt transfer experienced a phenomenon of “dehydration”, retaining less water. The 3 and 5 cm3 cubes marinated by immersion presented orange color tones due to the long processing time, while the probe system produced redder and brighter tones. Ultrasound as a technology to assist in marinades is not efficient for bacteria control of mesophilic, psychrophilic, or coliform. However, a significant increase in lactic acid bacteria (LAB) counts may bring benefits for meat preservation during refrigerated storage.

Effects of ultrasound-assisted heating on aroma profile, peptide structure, peptide molecular weight, antioxidant activities and sensory characteristics of natural fish flavouring

This study deals with the production of natural fish flavouring using ultrasound-assisted heating process. The effect of ultrasound pretreatment at different amplitudes (0, 15, 30, and 45%) on the Maillard reaction rate, antioxidant activities, flavour profile, and sensory characteristics of fish flavouring was investigated. Results showed that sonication markedly accelerated the Maillard reaction (MR) rate, as evidenced by the modification of peptide structure, a decrease in pH value, free amino acid content coupled with a rise in browning intensity. Also, ultrasound pretreatment significantly enhanced the antioxidant activities of fish flavouring (p ≤ 0.05). Moreover, sonication increased the type and content of aroma compounds significantly. Sensory analysis revealed that ultrasound pretreatment increased the fish-like and toasty aroma as well as umami and mouthfulness attributes coupled with the reduction of the bitter taste of the fish flavouring. This result was consistent with the GC-MS, electronic nose, cluster, and Partial Least Squares Regression (PLSR) analyses, which clearly showed that ultrasound pretreatment enhanced the fish-like aroma, which was associated with the increase in aldehydes, ketones, alcohols, thiophenes, pyrazine, and furans contents. Thus, it could be concluded that ultrasound pretreatment, coupled with the thermal process, could be a promising process for the production of natural fish flavouring with higher antioxidant activities.

Impact of combined ultrasound-microwave treatment on structural and functional properties of golden threadfin bream (Nemipterus virgatus) myofibrillar proteins and hydrolysates

The effects of microwave, ultrasound and combined ultrasound-microwave (UM) treatment with different intensities on structural and hydrolysis properties of myofibrillar protein (MP) were investigated. Freeradical scavenging ability, angiotensin-I-converting enzyme (ACE) inhibitory activity, and cellular antioxidant and anti-inflammatory abilities of the related bioactive peptides were also evaluated. Raman spectroscopic analysis indicated that MP molecule tended to unfold and stretch with increasing in β-turn and random coil content under mild microwave (100 W), ultrasound (100-200 W) and combined UM treatments. Meanwhile, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) revealed these treatments could also improve the thermal stability against heat-induced denaturation and degeneration. The 200 W ultrasound treatment clearly increased MP solubility by disrupting the highly-ordered aggregates into smaller filament and fragment structures. The 300 W ultrasound coupled with 100 W microwave treatment further enhanced these effects. The resulting partially denatured structure induced by suitable ultrasound and combined UM treatments increased the susceptibility of MP to exogenous enzymes, thereby accelerating hydrolytic process and yielding a high peptide concentration in MP hydrolysates. MP peptides could effectively inhibit free radical and ACE activity, which also improved the ability of antioxidant defence system, and suppressed the production of proinflammatory cytokines in RAW 264.7 cells stimulated by H₂O₂. The combination of 100 W microwave and 300 W ultrasound treatment was optimal method for generating bioactive MP peptides with the strongest multi-activity effects against H₂O₂-induced cell damage.

Effect of salt mixture on flavor of reduced-sodium restructured bacon with ultrasound treatment

Flavor loss from sodium reduction is a large challenge faced in the meat industry. The effects of salt mixture (KCl: CaCl2 = 1:1, w/w) content (0%-1.0%) on flavor of reduced-sodium (1.5% NaCl) restructured bacon with ultrasound treatment (UT, 600 w for 30 min) were investigated. The results showed that 0.5% salt mixture (0.25% KCl and 0.25% CaCl2) could significantly (p < .05) enhance the lipid oxidation, the protein oxidation, and the formation of free amino acids of reduced-sodium UT-restructured bacon and could also markedly (p < .05) improve its flavor and the overall quality of sensory evaluation via promoting the release of five kinds of volatile phenolic compounds (o-cresol, m-cresol, 2-methoxy-phenol, 2-methoxy-4-methylphenol, and 2-methoxy-5-methylphenol) and the formation of five kinds of volatile aldehyde compounds (hexanal, nonanal, decanal, furfural, and 5-methyl furfural). It is interesting to understand the mechanism for the effect of salt mixture on flavor and to efficiently develop a technique for improving the flavor of reduced-sodium products in the meat industry.

Antioxidant, Physicochemical, and Cellular Secretion of Glucagon-Like Peptide-1 Properties of Oat Bran Protein Hydrolysates

The aim of this work was to determine the physicochemical and biological activities of hydrolyzed proteins from sonicated oat brans. In addition to the control bran sample, two types of pre-treatment procedures-namely, ultrasonic bath and probe-type sonication-were performed to extract proteins, followed by hydrolysis with various proteases. Physicochemical analyses showed that Flavourzyme-hydrolysates had greater amounts of aromatic amino acids, Papain-hydrolysates low surface charges (-0.78 to -1.32 mV) compared to the others (-3.67 to -9.17 mV), and Alcalase-hydrolysates a higher surface hydrophobicity. The hydrolysates had good radical scavenging activities but, as the ultrasonic pre-treatment of the brans showed, in certain cases there was a reduction in activities of up to 22% for ROO^• and HO^• and 15% for O₂^•- radicals. In anti-diabetic tests, the maximum inhibition of α-amylase was 31.8%, while that of dipeptidyl peptidase-4 was 53.6%. In addition, the secretion of glucagon-like peptide-1 in NCI-H716 cells was enhanced by 11.5% in the presence of hydrolysates.

Structural and functional modification of food proteins by high power ultrasound and its application in meat processing

In the field of agricultural and food processing, high power ultrasound (HPUS) is recognized as a green, physical and non-thermal technology in improving the safety and quality of foods. The functional properties of food proteins are responsible for texture, yield and organoleptic of food products which are the theoretical basis for food processing optimizing. HPUS treatment could provide the possibility for creating novel functional properties of new foods with desirable properties due to the modification of protein structure. In this article, an overview of the previous studies and recent progress of the relationship between structure modification and functional properties of food proteins using the HPUS technique were presented. The research results revealed that HPUS could significantly affect the conformation and structure of protein due to the cavitation effect resulting in the improvement of solubility, interfacial, viscosity, gelation and flavor binding properties of proteins. During meat processing, HPUS can modify the structure and thereby improve the functional properties of myofibrillar protein (MP), leading to the quality enhancement, low fat and/or salt products development and the shelf life extending. In view of this review, the recent findings of applications of HPUS in the production of meat products based on the modification of MP including curing, freezing/thawing and thermal processing have been summarized. Finally, the future considerations were presented in order to facilitate the progress of HPUS in meat industry and provided the suggestions based on the advanced protein modification by HPUS for the commercial utilization of HPUS in producing the innovative meat products.

Application of ultrasound technology in processing of ready-to-eat fresh food: A review

With the increase in food standardization and the pace of modern life, the demand for ready-to-eat foods is growing. The strong processing conditions of traditional technology often accelerate the rate of deterioration of quality, and microbes are the safety hazard of ready-to-eat foods. Ultrasound technology is an environmentally friendly technology that hardly causes thermal damage to raw materials. In this paper, the ultrasound technology is used in the disinfection, sterilization, enzyme inactivation, desensitization, dehydration, curing, tenderization and cooking process of fresh food from the perspective of microbial safety and quality of fresh food. The cavitation effect of ultrasound can improve the mass transfer rate of infiltration processes such as dehydration and curing, promote the oxidation of lipids and proteins for enrich the flavor of meat products, improve the microbiological safety and reduce the sensitization by destroying the integrity of the microbial cells and the conformation of the protein. In addition, ultrasound as an auxiliary processing technology can reduce the damage of traditional production technology to reserve the quality and nutritional value of food. Ultrasound has proved to be an efficient and green processing technology for ready-to-eat food.

Influence of ultrasound pretreatment on the subsequent glycation of dietary proteins

The influence of ultrasound treatment on the subsequent glycation process of proteins is controversial. Glycation behaviors of bovine serum albumin (BSA), β-lactoglobulin (β-Lg) and β-casein (β-CN) after ultrasound pretreatment (UP) were compared by both evaluating glycation kinetics and analyzing structural changes of proteins. UP resulted in both unfolding and aggregation behavior in protein samples, which altered the accessibility of the Lys and Arg. Five cycles of UP up-regulated the glycation degree of BSA and β-Lg, possibly due to the unfolding behavior induced by UP, which exposed additional glycation sites. In contrast, 30 cycles of UP induced a dramatic increase (by 97.9 nm) in particle size of BSA, thus burying portions of glycation sites and suppressing the glycation process. Notably, UP had minimal influence on glycation kinetics of β-CN, due to its intrinsic disordered structure. Based on proteomics analysis, the preference of Lys and Arg during glycation was found to be changed by UP in BSA and β-Lg. Four, 3 and 3 unique carboxyethylated lysine residues were identified in glycated BSA after 0, 5 and 30 cycles of UP, respectively. This study suggests that the protein glycation can be affected by UP, depending on the ultrasonication duration and native structure of the protein.

Principles and applications of non-thermal technologies and alternative chemical compounds in meat and fish

Conventional methods of food preservation have demonstrated several disadvantages and limitations in the efficiency of the microbial load reduction and maintain food quality. Hence, non-thermal preservation technologies (NTPT) and alternative chemical compounds (ACC) have been considered a high promissory replacer to decontamination, increasing the shelf life and promoting low levels of physicochemical, nutritional and sensorial alterations of meat and fish products. The combination of these methods can be a potential alternative to the food industry. This review deals with the most critical aspects of the mechanisms of action under microbial, physicochemical, nutritional and sensorial parameters and the efficiency of the different NTPT (ultrasound, high pressure processing, gamma irradiation and UV-C radiation) and ACC (peracetic acid, bacteriocins, nanoparticles and essential oils) applied in meat and fish products. The NTPT and ACC present a high capacity of microorganisms inactivation, ensuring low alterations level in the matrix and high reduction of environmental impact. However, the application conditions of the different methods as exposition time, energy intensity and concentration thresholds of chemical compounds need to be specifically established and continuously improved for each matrix type to reduce to the maximum the physicochemical, nutritional and sensorial changes. In addition, the combination of the methods (hurdle concept) may be an alternative to enhance the matrix decontamination. In this way, undesirable changes in meat and fish products can be further reduced without a decrease in the efficiency of the decontamination.

High-intensity ultrasound applied on cured pork: Sensory and physicochemical characteristics

This research aimed to evaluate the physicochemical characteristics and their relationship with sensory properties of cured porcine m. longissimus lumborum assisted by high-intensity ultrasound (HIU, 37 kHz, 22 Wcm-2). An experiment was designed with three factors at two levels each: type of curing (immersion or ultrasound-assisted -UA-), immersion time (30 or 90 min), and steak thickness (1.27 or 2.54 cm). After treatment and 7 days of storage at 4°C, the percentage of salt, pH, CIE L* a* b* color, water holding capacity (WHC), and shear force were determined in the samples. A quantitative descriptive analysis was performed using eight trained panelists. The HIU significantly increased the percentage of NaCl (p < .0005) and decreased the color saturation of the meat (p < .05), but did not affect the luminosity, redness (a*), yellowness (b*), pH, WHC, or shear force (all p > .05). The thickness of the steak had significant effects on almost all of the evaluated variables. Samples with 1.27 cm thickness had lower shear force, higher WHC and salt percentage (p < .0001). In agreement with this, the sensory profiles showed that the 1.27 cm samples treated with HIU for 30 min were perceived as less tough (more tender) and juicier.

Amino Acid and Secondary Structure Integrity of Sonicated Milk Proteins

This study investigated the effect of low-frequency (20kHz) and high-frequency (414kHz) ultrasound treatment on the amino acid and secondary structural integrity of dairy proteins. Sonicated skim milk proteins were hydrolysed and analysed with reverse-phase high-performance liquid chromatography to investigate the amino acid content of the processed samples. It was successfully demonstrated that both low-frequency and high-frequency ultrasound did not adversely affect the amino acid content, even after prolonged extreme processing conditions (6h, 355kHz). This finding was supplemented with protein secondary structure data (Fourier-transform (FT)-IR secondary derivatives of the amide I band, 1700–1600cm−1) that showed that ultrasound was capable of causing structural modifications to the dairy proteins. This study shows that ultrasound can be used to influence protein–protein interactions in skim milk via alterations to the secondary structure without degrading the amino acids in the proteins.

Sono-physical and sono-chemical effects of ultrasound: Primary applications in extraction and freezing operations and influence on food components

Ultrasound is an advanced non-thermal food-processing technology that has received increasing amounts of interest as an alternative to, or an adjuvant method for, conventional processing techniques. This review explores the sono-physical and sono-chemical effects of ultrasound on food processing as it reviews two typical food-processing applications that are predominantly driven by sono-physical effects, namely ultrasound-assisted extraction (UAE) and ultrasound-assisted freezing (UAF), and the components modifications to food matrices that can be triggered by sono-chemical effects. Efficiency enhancements and quality improvements in products (and extracts) using ultrasound are discussed in terms of mechanism and principles for a range of food-matrix categories, while efforts to improve existing ultrasound-assist patterns was also seen. Furthermore, the progress of experimental ultrasonic equipments for UAE and UAF as food-processing technologies, the core of the development in food-processing techniques is considered. Moreover, sono-chemical reactions that are usually overlooked, such as degradation, oxidation and other particular chemical modifications that occur in common food components under specific conditions, and the influence on bioactivity, which was also affected by food processing to varying degrees, are also summarised. Further trends as well as some challenges for, and limitations of, ultrasound technology for food processing, with UAE and UAF used as examples herein, are also taken into consideration and possible future recommendations were made.

Influence of ultrasound-assisted sodium bicarbonate marination on the curing efficiency of chicken breast meat

Effects of ultrasound combined with sodium bicarbonate assisted curing (USC), sodium bicarbonate assisted curing (SC) and traditional wetting curing (WC) on curing efficiency and tenderization of the chicken breast meat were investigated. Compared with SC and WC treatments, the highest marinade uptake and chloride content were observed in USC treatment (P < 0.05). The lowest shear forces and the largest myofibril fragmentation indexes (MFI) were also obtained in USC chicken (6.99 N and 61.65) (P < 0.05), which were related to the larger gaps and cavities between the adjacent muscle bundles and the more broken muscle fibers in chicken by ultrasonic, followed by SC (8.01 N and 56.82) and WC (9.50 N and 52.23). Furthermore, the USC and SC decreased significantly the cooking loss and surface hydrophobicity of chicken (P < 0.05). Meanwhile, the USC and SC treatments gradually decreased the low-field nuclear magnetic resonance (LF-NMR) relaxation times (T₂₁ and T₂₂), which was related to the lower fluid losses in chicken. These results indicated that the USC and SC treatments had greater impact on the improvement of meat tenderization, water holding capacity and curing efficiency than WC, especially the USC was the best curing method.

Effect of Ultrasonic Treatment on Freeze-thaw Stability of Soy Protein Isolate Gel

This study investigated the impact of ultrasonic modification at various ultrasonic power extents on the freeze-thaw stability of soy protein isolate (SPI) gel. The freeze-thaw stability of the gel was evaluated by examining the changes in texture, water holding capacity, microstructure and soluble protein content during the process of 5 freeze-thaw cycles. In addition, effects on particle size, surface hydrophobicity and structure were also explored. The results showed that within a certain range, the average particle size of the protein gradually decreased, and the particle size distribution was narrower with ultrasonic intensity, it may be due to the high shear and cavitation effects of sonication that reduce the degree of protein aggregation. Furthermore, we also detected that treated proteins had lower fluorescence intensity, higher surface hydrophobicity and more flexible molecular structure with the reduction of α-helical structure as well as the rise of random coil. In terms of gel freeze-thaw stability, moderate ultrasound treatment made the water holding capacity and soluble protein content of SPI gel reduce by 38.27% and 3.58%, whereas the hardness and elasticity increased by 510.23g and 0.06mm after 5 FTC. The corresponding changes of indexes of the control group were 75.05%, 51%, 1062.75g and 0.11mm, respectively. It can be observed that the change range of treated SPI gel properties was smaller than that of natural SPI gel, indicating that ultrasonic treatment can remarkably improve the freeze-thaw stability of the gel which might have something to do with changes of protein structure.

Does ultrasound equally improve the quality of beef? An insight into longissimus lumborum, infraspinatus and cleidooccipitalis

Quality of bovine longissimus lumborum, infraspinatus and cleidooccipitalis muscles after high-intensity ultrasound (HIU; 40 kHz and a power of 11 W/cm² for 0, 40, 60, and 80 min) and aging (0, 7 and 14 d) was evaluated. The effects of HIU on pH and color of meat were not considered negative. HIU improved water holding capacity (WHC) of l.lumborum and infraspinatus only after aging. Whereas, the WHC of cleidooccipitalis increased immediately after sonication. The total collagen of HIU treated samples was significantly lower compared to the untreated samples. Ultrasonication for 80 min was the most effective for infraspinatus and cleidooccipitalis. Toughness decreased with HIU, iii nfraspinatus and l.lumborum tenderized more than cleidooccipitalis. HIU application and 7 d aging is an excellent combined treatment to improve tenderness of the three muscles. Infraspinatus was the most tender meat. HIU could help industry to improve the quality of beef as it helps in tenderization and accelerates maduration particularly of l.lumborum.