Effect of ultrasound treatment on particle size and molecular weight of whey proteins

Combined pulsed electric field-ultrasound assisted extraction of yarrow phenolic-rich ingredients and their nanoliposomal encapsulation for improving the oxidative stability of sesame oil

In this research, yarrow phenolic-rich extract was produced using pulsed electric field (PEF)-ultrasound assisted technology. The highest extraction efficiency (5.99 %) was obtained at 6.25 kV/cm of PEF and the sonication time of 60 min. As the PEF intensity and sonication time rose, the total phenolic content (TPC) and ferric-reducing power (RP) of the extracts increased. The PEF intensity of 2.70 kV/cm and sonication time of 45.83 min were the optimum extraction conditions resulting in the highest extraction efficiency, TPC, and RP. Then, this optimum extract was loaded into nanoliposomes. At higher extract levels, the encapsulation efficiency lowered, while the particle size, polydispersity index (PDI), and zeta potential of the nanoliposomal samples elevated. The results of Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) confirmed the successful encapsulation of yarrow extract into nanoliposomal carriers; the sample containing the extract had the highest enthalpy (3600 J/g) and nanoliposomes loaded with yarrow antioxidant extract (0.11 mL/mg) was the optimum sample. Finally, the sesame oil containing 500 ppm free and nanoliposome extract, as well as the sample with 200 ppm BHT were evaluated for oxidative stability. The highest oxidation stability (14.21 h) belonged to the oil containing nanoliposomal yarrow phenolic extract.

Effects of ultrasonic treatment on the structure and functional characteristics of myofibrillar proteins from black soldier fly

In the process of utilizing black soldier fly larvae (BSFL) lipids to develop biodiesel, many by-products will be produced, especially the underutilized protein components. These proteins can be recycled through appropriate treatment and technology, such as the preparation of feed, biofertilizers or other kinds of bio-products, so as to achieve the efficient use of resources and reduce the generation of waste. Myofibrillar protein (MP), as the most important component of protein, is highly susceptible to environmental influences, leading to oxidation and deterioration, which ultimately affects the overall performance of the protein and product quality. For it to be high-quality and fully exploited, in this study, black soldier fly myofibrillar protein (BMP) was extracted and primarily subjected to ultrasonic treatment to investigate the impact of varying ultrasonic powers (300, 500, 700, 900 W) on the structure and functional properties of BMP. The results indicated that as ultrasonic power increased, the sulfhydryl content and turbidity of BMP decreased, leading to a notable improvement in the stability of the protein emulsion system. SEM images corroborated the changes in the microstructure of BMP. Moreover, the enhancement of ultrasound power induced modifications in the intrinsic fluorescence spectra and FTIR spectra of BMP. Additionally, ultrasonic treatment resulted in an increase in carbonyl content and emulsifying activity of BMP, with both peaking at 500 W. It was noteworthy that BMP treated with ultrasound exhibited stronger digestibility compared to the untreated. In summary, 500 W was determined as the optimal ultrasound parameter for this study. Overall, ultrasound modification of insect MPs emerges as a dependable technique capable of altering the structure and functionality of BMP.

Effect of ultrasound treatment on quality parameters and health promoting activity of fish protein hydrolysates extracted from side streams of Atlantic mackerel (Scomber scombrus)

Fish protein hydrolysates (FPH) obtained by enzymatic hydrolysis allows for smart valorization of fish side streams. However, further treatments are normally needed to enhance bioactive and functional properties of the obtained FPH. At present, the commonly used methods to improve functional properties of FPH include chemical and enzymatic modification. Chemical treatments often cause environmental problems, while the enzymatic modification method requires the use of quite expensive enzymes. In recent years, emerging technologies such as ultrasound treatment (US-treatment) have shown great potential in protein modification with high efficiency and safety, low energy consumption, and low nutritional destructiveness. In this study, high-power ultrasound treatments were applied to fish protein hydrolysates (FPH) extracted from Atlantic mackerel (Scomber scombrus) side streams to improve their quality parameters. The effect of three different treatments of 300 W, 450 W and 600 W at the operating frequency of 20 kHz for 10 min on the physicochemical, structural, and functional characteristics of FPH, were examined. The results have shown that with an increase in ultrasound power, the protein solubility of FPH increased linearly, and the changes were significant for all US-treated samples compared to control (untreated) samples. US-treatment significantly increased the degree of hydrolysis of FPH samples treated with 450 W and 600 W compared to control samples. The carbonyl content of FPH increased (significantly for 450 W and 600 W), while thiol groups decreased (significantly for 300 W and 450 W). This indicated that some US-treatments induced oxidation of FPH, however the values of the protein oxidation were low. Amino acid composition of FPH revealed that US-treatment increased the proportion of essential amino acids in the sample treated with 300 W and 450 W, but the increase was not significant. After the US-treatment, all FPH samples became lighter and less yellowish and reddish, which suggest potentially higher attractiveness to consumers. In addition, the in vitro antioxidant activity was assessed using the DPPH, FRAP, and ABTS assays and the cell-free dipeptidyl peptidase IV (DPP-IV) inhibitory activity was also measured. Moreover, these biological activities were measured at cellular level utilizing human intestinal Caco-2 cells. Specifically, the FPH capacity to lower H2O2-induced reactive oxygen species (ROS) and lipid peroxidation levels was used to measure its antioxidant activity. The findings suggest that Scomber scombrus hydrolysates could find use as ingredients for promoting health.

Effect of thermal and non-thermal processing methods on the Structural and Functional Properties of Whey Protein from Donkey Milk

This study evaluated the impact of thermal, ultrasonication, and UV treatment on the structural and functional properties of whey proteins from donkey milk (DWP). Whey proteins exhibited notable stability in non-heat-treated environments, while their structural and functional characteristics were notably impacted by excessive heat treatment. The application of high-temperature long-time thermal treatment (HTLT) resulted in a decrease in fluorescence intensity, foaming and emulsification stability, and considerable damage to the active components of the proteins. Specifically, the preservation of lysozyme activity was only 23%, and lactoferrin and immunoglobulin G exhibited a significant loss of 70% and 77%, respectively. Non-thermal treatment methods showed superior efficacy in preserving the active components in whey proteins compared with heat treatment. Ultrasonic treatment has demonstrated a notable capability in diminishing protein particle size and turbidity, and UV treatment has been observed to have the ability to oxidize internal disulfide bonds within proteins, consequently augmenting the presence of free sulfhydryl groups, which were beneficial to foaming and emulsification stability. This study not only offers a scientific basis for the processing and application of DWP but also serves as a guide to produce dairy products, aiding in the development of dairy products tailored to specific health functions.

Improvement of jelly 3D printing using ultrasound treatment and calcium chloride

This study investigated the effects of ultrasound treatment or calcium chloride (CaCl2) addition on the physical properties of jelly formulations. Elastic modulus (G'), loss modulus (G"), tan δ, shear modulus, yield stress (τ0), phase angle (δ), and gel strength were the parameters selected to describe the requirements of jelly printing, such as fidelity, shape retention, and extrudability. Ultrasound treatment of the jelly formulation without pectin increased the G' and shear moduli values, while decreasing the δ and gel strength. The addition of CaCl2 to the jelly formulation with pectin increased the G', G", shear modulus, τ0, and gel strength but lowered the tan δ and δ values. Both ultrasound treatment and CaCl2 addition improved the jelly printing requirements and demonstrated the potential to control the physical properties of jelly formulations for 3D printing using fused deposition modeling.

FT-IR-based fingerprint combined with unsupervised chemometric analysis revealed particle sizes and aqueous-ethanol ratio alter the chemical composition and nutraceutical value of Daucus carota

This study reported the effects of particle size of dry powder and the optimum solvent extraction on the nutraceutical value of carrot by observing its FT-IR fingerprint, TPC, TFC, and antioxidant activity. The dried-powdered carrot was ultrasound-assisted extracted using EtOH, water, and EtOH-water. The TFC, TPC, and antioxidant activity were analysed by a colorimetric method using a spectrophotometry UV-Vis. The chemotaxonomy of samples was analysed using FT-IR combined with chemometrics analysis. The TFC, TPC, and antioxidant capacity were significantly different for each sample with the highest TFC, TPC, and antioxidant obtained on particle size 149 μm with EtOH-water (50:50) as the most prominent solvent (19.51 mgQE/g, 9.90 mgGAE/g, IC50: 16.7 ± 0.89 µg/mL). FT-IR profiling of samples also illustrates a minor different pattern of the spectrum, indicating there is a difference in their chemical composition. The particle size and EtOH-water ratio influence the chemical composition and antioxidant activity of carrots.

Effect of enzymatic hydrolysis with Alcalase or Protamex on technological and antioxidant properties of whey protein hydrolysates

The aim of this study was to evaluate the effect of the enzymatic hydrolysis, performed using Alcalase and Protamex enzymes, on the technological functionalities and the antioxidant capacity of whey protein hydrolysates (WPHs) to identify the conditions allowing to obtain target functionality/ies. Samples were characterized for hydrolysis degree (DH), molecular weight distribution, structural properties, and food-related functionalities. Free sulfhydryl groups and surface hydrophobicity significantly decreased with the increase in DH, regardless of the used enzyme. The foaming and antioxidant properties of Alcalase WPHs were higher as compared to those of WPI, reaching the maximum value at DH = 18-20 %, while higher DH resulted in impaired functionality. Gelling properties were guaranteed when WPI was hydrolysed by Protamex at DH < 15 % while foaming and antioxidant abilities were fostered at 15 < DH < 21 %. These results were well correlated with MW distribution and were rationalized into a road map which represents a useful tool in the selection of proper hydrolysis conditions (time, DH, enzyme type) to obtain WPHs with tailored functionalities. Research outcomes highlighted the possibility to drive protein hydrolysis to optimize the desired functionality/ies.

High-intensity ultrasound treatment of Atlantic cod: Impact on nutrients, structure, sensory quality, bioactivity, and in-vitro digestibility

This study evaluates the impact of high-intensity ultrasound (HIU) on the physicochemical properties and in-vitro digestibility of Atlantic cod (Gadus morhua). Various ultrasound durations (0-60 min) were applied to assess changes in color attributes, total antioxidant capacity (TAC), total flavonoid content (TFC), total phenolic content (TPC), total protein content, and in-vitro protein digestibility (IVPD). Results indicated HIU maximumly increased TAC, TFC, TPC, and peptide content before digestion by 7.28 % (US60), 3.00 % (US30), 32.43 % (US10), and 18.93 % (US60), respectively. While HIU reduced total protein content, it enhanced IVPD by up to 12.24 % (US30). Color attributes electron microscopy reflected structural changes in the cod samples, suggesting the effectiveness of HIU in altering protein structures. These findings highlight HIU's potential as a non-thermal technique for improving the sensory and nutritional quality of Atlantic cod, offering valuable insights for the seafood processing industry and consumers.

Strategies to Improve the Quality of Goat Yogurt: Whey Protein Supplementation and Milk Pre-Treatment with High Shear Dispersion Assisted by Ultrasound

This work investigated the fermentation kinetics and characteristics of goat yogurt supplemented with bovine whey protein isolate (WPI) (0%, 2.5% and 5.0%) subjected to high shear dispersion (HSD) assisted by ultrasound (US). Protein supplementation and the physical processes increased the electronegativity of the zeta potential (≤60%), whereas particle size reduction was observed only with physical processes (≤42%). The addition of 2.5% WPI reduced yogurt fermentation time by 30 min. After 24 h of storage at 7 °C, lactic acid bacteria counts did not differ between samples (≥8 log CFU/mL), and the supplementation was sufficient to increase the apparent viscosity (≤5.65 times) and water-holding capacity (WHC) of the yogurt (≤35% increase). However, supplementation combined with physical processes promoted greater improvements in these parameters (6.41 times in apparent viscosity and 48% in WHC) (p < 0.05), as confirmed by the denser and better-organized protein clusters observed in microscopic evaluation. Thus, both approaches proved to be promising alternatives to improve goat yogurt quality. Therefore, the decision to adopt these strategies, either independently or in combination, should consider cost implications, the product quality, and market demand.

Modification of the physicochemical, functional, biochemical and structural properties of a soursop seed (Annona muricata L.) protein isolate treated with high-intensity ultrasound

The obtained seeds from fruit processing are considered by-products containing proteins that could be utilized as ingredients in food manufacturing. However, in the specific case of soursop seeds, their usage for the preparation of protein isolates is limited. In this investigation a protein isolate from soursop seeds (SSPI) was obtained by alkaline extraction and isoelectric precipitation methods. The SSPI was sonicated at 200, 400 and 600 W during 15 and 30 min and its effect on the physicochemical, functional, biochemical, and structural properties was evaluated. Ultrasound increased (p < 0.05) up to 5 % protein content, 261 % protein solubility, 60.7 % foaming capacity, 30.2 % foaming stability, 86 % emulsifying activity index, 4.1 % emulsifying stability index, 85.4 % in vitro protein digestibility, 423.4 % albumin content, 83 % total sulfhydryl content, 316 % free sulfhydryl content, 236 % α-helix, 46 % β-sheet, and 43 % β-turn of SSPI, in comparison with the control treatment without ultrasound. Furthermore, ultrasound decreased (p < 0.05) up to 50 % particle size, 37 % molecular flexibility, 68 % surface hydrophobicity, 41 % intrinsic florescence spectrum, and 60 % random coil content. Scanning electron microscopy analysis revealed smooth structures of the SSPI with molecular weights ranging from 12 kDa to 65 kDa. The increase of albumins content in the SSPI by ultrasound was highly correlated (r = 0.962; p < 0.01) with the protein solubility. Improving the physicochemical, functional, biochemical and structural properties of SSPI by ultrasound could contribute to its utilization as ingredient in food industry.

Ultrasound viscous reduction effects on the proteolysis of soy protein isolate at a limited degree of hydrolysis: Changes in the functional characteristics and protein structure

High-concentration soy protein isolate was subjected to ultrasonication for viscosity reduction to assist the process of limited enzymatic hydrolysis. Ultrasonication (20 kHz, 10 min, 160 W/L) effectively reduced the viscosity of soy protein isolate at a comparatively high concentration of 14 % (w/v) and promoted the limited enzymatic hydrolysis (controlled degree of hydrolysis of 12 %) with a higher peptide yield than that of the conventional method. The correlations between substrate viscosity and peptide yield, as well as the viscosities of the resulting hydrolysates, were studied. The findings revealed positive correlations between the viscosities of the substrate and hydrolysate, underscoring the potential impact of altering substrate viscosity on the final product. Furthermore, the utilization of ultrasonic viscosity reduction-assisted proteolysis has shown its capability to improve the functional and physicochemical properties, as well as the protein structure of the hydrolysate, while maintaining the same level of hydrolysis. It is worth noting that there were significant alterations in particle size (decrease), β-sheet content (increase), β-turn content (increase), and random coil content (increase). Interestingly, ultrasonication unexpectedly impeded the degradation of molecular mass in proteins during proteolysis, while increasing the hydrophobic properties of the hydrolysate. These findings aligned with the observed reduction in bitterness and improvement in emulsifying properties and water-holding capacity.

Structure and functionality of whey protein, pea protein, and mixed whey and pea proteins treated by pH shift or high-intensity ultrasound

Three modifications (pH shift, ultrasound, combined pH shift and ultrasound) induced alterations in pure whey protein isolate (WPI), pea protein isolate (PPI), and mixed whey and pea protein (WPI-PPI) were investigated. The processing effect was related to the protein type and technique used. Solubility of WPI remained unchanged by various treatments. Particle size was enlarged by pH shift while reduced by ultrasound and combined approach. All methods exposed more surface hydrophobic groups on WPI, while pH shift and joint processing was detrimental to its emulsifying activity. The PPI and mixture exhibited similar responses toward the modifications. Solubility of PPI and the blend enhanced in the sequence of pH shift and ultrasound > ultrasound > pH shift. Individual approach expanded while co-handling diminished the particle diameter. Treatments also caused more disclosure of hydrophobic regions in PPI and WPI-PPI and emulsifying activity was ameliorated in the order of pH shift and ultrasound > ultrasound > pH shift.

Clean-In-Place (CIP) wastewater management using nanofiltration (NF)-forward osmosis (FO)-direct contact membrane distillation (DCMD): Effects of draw salt

A substantial amount of water is being used during Clean-in-Place (CIP) operation, and is transformed into wastewater that can cause eutrophication to the nearby ecosystem. The present study proposed the Nanofiltration (NF) - Forward Osmosis (FO) - Direct Contact Membrane Distillation (DCMD) to recover the cleaning agents and reclaim freshwater from the model CIP wastewater. NF steps were suggested as prefiltration steps to remove organic compounds from the CIP wastewater. NF steps reduced the lactose and protein contents by 100 % and 95.6 %, respectively. The permeates from NF steps were further managed by the integrated FO-DCMD system. Several draw salts such as NaCl, KCl, MgCl2, and CaCl2 were compared to investigate the influence on FO and DCMD performance. It was found that monovalent salts (NaCl and KCl) outperformed the divalent salts (MgCl2 and CaCl2) in terms of water flux for both FO and DCMD. This can be attributed to the lower viscosity and higher mass transfer coefficient. In addition, the replenishment costs of each salt were evaluated since salts loss occurred during FO and DCMD operation. The cost evaluation revealed that NaCl is most the cheapest salts per reclaimed water. All of this observation indicates that NaCl is preferred in terms of water flux and replenishment cost. The NF permeate kept concentrated using the integrated FO-DCMD or single FO with 2 M of NaCl. Compared to a single FO that showed a consistent decline in draw solution concentration, FO-DCMD could maintain the concentration of the draw solution. Despite the constant concentration, flux decline of FO was observed due to fouling formation caused by the high-temperature operation. However, the FO-DCMD could accomplish the recovery of pure water. Finally, the cleaning agents recovered by the NF-FO-DCMD showed the cleaning efficacy comparable to the fresh NaOH. These results suggest the potential of the proposed system to manage the CIP wastewater.

Use of high-intensity ultrasound as a pre-treatment for complex coacervation from whey protein isolate and iota-carrageenan

The aim of this work was to evaluate the influence of high intensity ultrasound (HIUS) treatment on the molecular conformation of whey protein isolated (WPI) as a previous step for complex coacervation with iota carrageenan (IC) and its effect on the surface functional properties of complex coacervates (CC). Both biopolymers were hydrated (1% w/w) separately. A WPI suspension was treated with an ultrasonic bath (40 kHz, 600 W, 30 and 60 min, 100% amplitude). A non-sonicated protein was used as a control. Coacervation was achieved by mixing WPI and IC dispersions (10 min). FTIR-ATR analysis (400-4000 cm-1) detected changes after sonication on WPI secondary structure (1600-1700 cm-1), electrostatic interaction between WPI and IC by electronegative IC charged groups like sulfate (1200-1260 cm-1), anhydrous oxygen of the 3.6 anhydro-D-galactose (940-1066 cm-1) and the electropositive regions of WPI. Rheology results showed pseudoplastic behavior of both IC and WPI-IC with a significant change in viscosity level. Further, HIUS treatment had a positive effect on the emulsifying properties of the WPI-IC coacervates, increasing the time foaming (30 min) and emulsion stability (1 month) percentage. HIUS and complex coacervation proved to be an efficient tool to improve the surface functional properties of WPI.

A novel strategy for improving the stability of myofibrillar protein emulsions at low ionic strength using high-intensity ultrasound combined with non-enzymatic glycation

Poor emulsification of myofibrillar proteins (MPs) limits the production of meat protein emulsion-type products, and it is related to the myosin self-assembles in low-salt settings. The effect of high-intensity ultrasound (HIU) pretreatment combined with non-enzymatic glycation on MP-stabilized emulsions in low-salt settings was investigated in this study, and the potential mechanism was revealed. The results indicated that, compared to using either HIU or glycation treatment alone, HIU pretreatment in combination with glycation significantly improves the physical stability of emulsions while increasing the distribution uniformity and reducing the droplet particle size from 18.05 μm to 2.54 μm (P < 0.05). Correspondingly, the emulsion prepared using this approach exhibited a relatively high absolute zeta potential (-23.58 mV) and a high interfacial protein content (38.78 %) (P < 0.05), promoting molecular rearrangement and forming a continuous and stable interfacial layer. HIU pretreatment combined with glycation could offer reinforced electrostatic repulsion and steric hindrance to depolymerize self-assembled filamentous polymers, thus enhancing the stability of droplets. Additionally, the thermal sensitivity of the glycated MPs pretreated by HIU was remarkably reduced, thus improving the thermal stability of the corresponding emulsions.

High-intensity ultrasound combined with glycation enhances the thermal stability and in vitro digestion behaviors of myofibrillar protein aqueous solution

The low thermal stability of myofibrillar proteins (MPs) is a technological barrier to them being applied in beverage formulas. In this study, we investigated the effect of high-intensity ultrasound (HIU) pretreatment combined with glycation on the thermal stability, structural characteristics, and in vitro digestion behavior of MPs in water. The results indicated that HIU pretreatment combined with glycation significantly inhibited thermal aggregation and reduced the particle size of MPs compared to using either HIU or glycation treatments individually. The grafting of dextran (DX) shielded the sulfhydryl (-SH) and hydrophobic groups and inhibited disulfide bond cross-linking and hydrophobic association. Moreover, HIU pretreatment facilitated the shielding effect of glycation by destroying the filamentous myosin structure and exposing the internal -SH and hydrophobic groups as well as the grafting sites, maximally inhibiting thermal aggregation. In addition, the smaller protein particles and more flexible structure caused by HIU pretreatment combined with glycation increased their binding affinity toward protease. Overall, these findings can promote the technological development of modulating the MP structure-digestion for formulating novel meat protein-based products.

Ultrasonic and homogenization: An overview of the preparation of an edible protein-polysaccharide complex emulsion

Emulsion systems are extensively utilized in the food industry, including dairy products, such as ice cream and salad dressing, as well as meat products, beverages, sauces, and mayonnaise. Meanwhile, diverse advanced technologies have been developed for emulsion preparation. Compared with other techniques, high-intensity ultrasound (HIUS) and high-pressure homogenization (HPH) are two emerging emulsification methods that are cost-effective, green, and environmentally friendly and have gained significant attention. HIUS-induced acoustic cavitation helps in efficiently disrupting the oil droplets, which effectively produces a stable emulsion. HPH-induced shear stress, turbulence, and cavitation lead to droplet disruption, altering protein structure and functional aspects of food. The key distinctions among emulsification devices are covered in this review, as are the mechanisms of the HIUS and HPH emulsification processes. Furthermore, the preparation of emulsions including natural polymers (e.g., proteins-polysaccharides, and their complexes), has also been discussed in this review. Moreover, the review put forward to the future HIUS and HPH emulsification trends and challenges. HIUS and HPH can prepare much emulsifier-stable food emulsions, (e.g., proteins, polysaccharides, and protein-polysaccharide complexes). Appropriate HIUS and HPH treatment can improve emulsions' rheological and emulsifying properties and reduce the emulsions droplets' size. HIUS and HPH are suitable methods for developing protein-polysaccharide forming stable emulsions. Despite the numerous studies conducted on ultrasonic and homogenization-induced emulsifying properties available in recent literature, this review specifically focuses on summarizing the significant progress made in utilizing biopolymer-based protein-polysaccharide complex particles, which can provide valuable insights for designing new, sustainable, clean-label, and improved eco-friendly colloidal systems for food emulsion. PRACTICAL APPLICATION: Utilizing complex particle-stabilized emulsions is a promising approach towards developing safer, healthier, and more sustainable food products that meet legal requirements and industrial standards. Moreover, the is an increasing need of concentrated emulsions stabilized by biopolymer complex particles, which have been increasingly recognized for their potential health benefits in protecting against lifestyle-related diseases by the scientific community, industries, and consumers.

3D Printing of Bioactive Gel-like Double Emulsion into a Biocompatible Hierarchical Macroporous Self-Lubricating Scaffold for 3D Cell Culture

The interconnected hierarchically porous structures are of key importance for potential applications as substrates for drug delivery, cell culture, and bioscaffolds, ensuring cell adhesion and sufficient diffusion of metabolites and nutrients. Here, encapsulation of a vitamin C-loaded gel-like double emulsion using a hydrophobic emulsifier and soy particles was performed to develop a bioactive bioink for 3D printing of highly porous scaffolds with enhanced cell biocompatibility. The produced double emulsions suggested a mechanical strength with the range of elastic moduli of soft tissues possessing a thixotropic feature and recoverable matrix. The outstanding flow behavior and viscoelasticity broaden the potential of gel-like double emulsion to engineer 3D scaffolds, in which 3D constructs showed a high level of porosity and excellent shape fidelity with antiwearing and self-lubricating properties. Investigation of cell viability and proliferation using fibroblasts (NIH-3T3) within vitamin C-loaded gel-like bioinks revealed that printed 3D scaffolds offered brilliant biocompatibility and cell adhesion. Compared to scaffolds without encapsulated vitamin C, 3D scaffolds containing vitamin C showed higher cell viability after 1 week of cell proliferation. This work represented a systematic investigation of hierarchical self-assembly in double emulsions and offered insights into mechanisms that control microstructure within supramolecular structures, which could be instructive for the design of advanced functional tissues.

Non-thermal techniques as an approach to modify the structure of milk proteins and improve their functionalities: a review of novel preparation

BACKGROUND

Milk proteins (MPs) have been widely used in the food industry due to their excellent functionalities. However, MPs are thermal-unstable substances and their functional properties are easily affected by heat treatment. Emerging non-thermal approaches (i.e., high-pressure homogenization (HPH), ultrasound (US), pulsed electric field (PEF)) have been increasingly popular. A detailed understanding of these approaches' impacts on the structure and functionalities of MPs can provide theoretical guidance for further development to accelerate their industrialization.

SCOPE AND APPROACH

This review assesses the mechanisms of HPH, US and PEF technologies on the structure and functionalities of MPs from molecular, mesoscopic and macroscopic levels, elucidates the modifications of MPs by these theologies combined with other methods, and further discusses their existing issues and the development in the food filed.

KEY FINDINGS AND CONCLUSIONS

The structure of MPs changed after HPH, US and PEF treatment, affecting their functionalities. The changes in these properties of MPs are related to treated-parameters of used-technologies, the concentration of MPs, as well as molecular properties. Additionally, these technologies combined with other methods could obtain some outstanding functional properties for MPs. If properly managed, these theologies can be tailored for manufacturing superior functional MPs for various processing fields.

Influence of High-Intensity Ultrasound on Characteristics and Bioaccessibility of Pea Protein in Fiber-Enriched Suspensions

Pea protein is of high interest for the food industry owing to its low allergenicity and high nutritional value. However, it often exhibits poor functionality, such as low solubility. The presence of dietary fiber in food products is beneficial for human health but may decrease the bioaccessibility of nutrients. Ultrasound, as a promising green technology, may influence properties of fibers and proteins and, thus, bioaccessibility. Therefore, this study investigated the effects of high-intensity ultrasound on the characteristics and protein bioaccessibility of protein-fiber suspensions. Suspensions containing different fiber compounds (1 wt.%) and pea protein (5 wt.%) were homogenized using high-intensity ultrasound (amplitude 116 µm, t = 150 s, energy density = 225 kJ/L, P¯ = 325 W). Owing to sonication-induced cavitation, the dispersibility of the protein was enhanced, and the viscosity of solutions containing citrus or apple fiber was increased. FE-SEM revealed the formation of different fiber-protein networks during sonication. Even if viscosity is known to have an impact on the bioaccessibility of nutrients, no restrictions on the digestibility of protein were detected during an in vitro digestion. Thus, protein uptake is probably not affected, and ultrasound can be used to modify the technofunctionality of fibers and proteins without any nutritional disadvantages.

Ultrasound treated fish myofibrillar protein: Physicochemical properties and its stabilizing effect on shrimp oil-in-water emulsion

Effects of ultrasonication at different amplitudes (40% and 60%) and time (5, 10, and 15 min) on the physicochemical and emulsifying properties of the fish myofibrillar protein (FMP) were investigated. Solubility, surface hydrophobicity, and emulsifying properties were augmented when FMP was subjected to ultrasonication at 40% amplitude for 15 min (p < 0.05). Protein pattern study revealed that augmenting amplitude and duration of ultrasound treatment reduced band intensity of myosin heavy chain. Ultrasound treatment facilitated the adsorption of FMP on oil droplets as indicated by the increases in both adsorbed and interfacial protein contents (p < 0.05). Ultrasound-treated FMP (UFMP) sample showed the alteration in chemical bonds as depicted by Fourier transform infrared (FTIR) spectra. Ultrasound treatment altered the β-sheet and random coil of FMP. During storage for 30 days at 30 °C, UFMP stabilized shrimp oil (SO)-in-water emulsion had higher turbidity but lower d₃₂, d₄₃, and polydispersity index than emulsion stabilized by untreated FMP (p < 0.05). Furthermore, emulsion stabilized by UFMP had lower flocculation and coalescence indices (p < 0.05). Microstructure observation revealed smaller droplet sizes and higher stability of droplets in emulsion stabilized by UFMP. Confocal laser scanning microscopic images demonstrated a monodisperse emulsion stabilized by UFMP. This coincided with higher viscosity and modulus values (G' and G″ ). Emulsion stabilized by UFMP exhibited viscous, shear-thinning, and non-Newtonian behavior and no phase separation occurred during storage. Therefore, ultrasonication was proven to be a potential method for enhancing the emulsifying properties of FMP and improving the stability of SO-in-water emulsion during prolonged storage.

Effects of ultrasound treatment on the morphological characteristics, structures and emulsifying properties of genipin cross-linked myofibrillar protein

Genipin is a natural crosslinker that improves the functional properties of proteins by modifying its structures. This study aimed to investigate the effects of sonication on the emulsifying properties of different genipin concentration-induced myofibrillar protein (MP) cross-linking. The structural characteristics, solubility, emulsifying properties, and rheological properties of genipin-induced MP crosslinking without sonication (Native), sonication before crosslinking (UMP), and sonication after crosslinking (MPU) treatments were determined, and the interaction between genipin and MP were estimated by molecular docking. The results demonstrated that hydrogen bond might be the main forces for genipin binding to the MP, and 0.5 μM/mg genipin was a desirable concentration for protein cross-linking to improve MP emulsion stability. Ultrasound treatment before and after crosslinking were better than Native treatment to improve the emulsifying stability index (ESI) of MP. Among the three treatment groups at the 0.5 μM/mg genipin treatment, the MPU treatment group showed the smallest size, most uniform protein particle distribution, and the highest ESI (59.89%). Additionally, the highest α-helix (41.96%) in the MPU + G5 group may be conducive to the formation of a stable and multilayer oil-water interface. Furthermore, the free groups, solubility, and protein exposure extent of the MPU groups were higher than those of UMP and Native groups. Therefore, this work suggests that the treatment of cross-linking followed by ultrasound (MPU) could be a desirable approach for improving the emulsifying stability of MP.

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.

Effect of Thermosonication on Amino Acids, Phenolic Compounds, Sensory Properties and Microbial Quality in Freshly Squeezed Verjuice

Thermosonication is a process that can be used as an alternative to thermal pasteurization by combining mild temperature and ultrasound treatments. This study evaluated the effects of verjuice on the thermosonication process and its bioactive values modeled with the RSM (response surface method). The bioactive components of verjuice were found to increase with high predictive values. Additionally, the presence and amounts of 20 free amino acids in C-VJ (untreated verjuice), P-VJ (thermally pasteurized verjuice) and TS-VJ (thermosonicated verjuice) samples were investigated. Significant (p < 0.05) differences were detected among C-VJ, P-VJ and TS-VJ samples in all free amino acid values except methionine. Although 17 free amino acids were detected at various concentrations, glycine, taurine and cystine were not found in any samples. Thirteen phenolic filters in C-VJ, P-VJ and TS-VJ samples were also examined in this study. Eight phenolic donors with various abilities were detected in the C-VJ sample, along with nine phenolic acceptors in the P-VJ sample and eleven phenolic contents in the TS-VJ sample. The content of phenolic products in the TS-VJ sample increased by 37.5% compared to the C-VJ techniques and by 22.22% compared to the P-VJ techniques. Thermosonication did not significantly affect color and physiochemical values. Panelists generally appreciated the effects of thermosonication. It is concluded that the thermosonication process is a good alternative to thermal pasteurization. The results of this study provide essential data for future in vivo studies and show that the bioactive values of verjuice can be increased by using the thermosonication process.

Recovery of cleaning agents from Clean-In-Place (CIP) wastewater using nanofiltration (NF) and direct contact membrane distillation (DCMD)

Increasing concerns about freshwater sources necessitate the management of wastewater, such as the wastewater generated from Clean-in-Place (CIP) operations. In this investigation, a membrane system composed of nanofiltration (NF) and direct contact membrane distillation (DCMD) was proposed to manage model dairy CIP wastewater that contained NaOH as an alkaline cleaning agent. During the NF step, prefiltration by a 4 kDa membrane or a 4 kDa membrane followed by a 200 Da membrane (4 kDa/200 Da) was used to remove the whey protein and lactose. With these two membranes in series of NF, the protein concentration was reduced by 92.4% and the lactose content was reduced to a non-detectable level when compared to the model CIP wastewater. Before concentrating the permeates from NF steps, three DCMD membranes (FR, Solupor, and ST) with different characteristics were evaluated to manage the NF permeates from 4 kDa or 200 Da NF. An increase in the feed temperature from 40 °C to 60 °C resulted in an increase in the water flux during DCMD operation, except for FR. In addition, it was found that ST generated the highest water flux when compared to the other membranes. Using ST and a feed temperature of 60 °C, the permeates from 4 kDa or 4 kDa/200 Da were continuously concentrated for 7 h with DCMD. During this concentration, there was no significant decline in flux. The cleaning effectiveness of the cleaning agent (NaOH) recovered by NF and DCMD was compared with a fresh cleaning solution using quartz crystal microbalance with dissipation (QCM-D). It was found that the cleaning agents recovered by 4 kDa/200 Da NF presented a statistically identical cleaning rate compared to fresh NaOH. This research highlights the potential of NF and DCMD to regenerate alkaline cleaning agents, while reclaiming water from dairy CIP wastewater.

Effects of dual succinylation and ultrasonication modification on the structural and functional properties of ovalbumin

In this study, the functional properties of ovalbumin (OVA) were improved through dual modification with succinylation (succinylation degrees of 32.1 % [S1], 74.2 % [S2], and 95.2 % [S3]) and ultrasonication (ultrasonication durations of 5 min [U1], 15 min [U2], and 25 min [U3]), and the changes in protein structures were explored. Results showed that as the succinylation degree was increased, the particle size and surface hydrophobicity of S-OVA decreased by the maximum values of 2.2 and 2.4 times, respectively, causing emulsibility and emulsifying stability to increase by 2.7 and 7.3 times, respectively. After ultrasonic treatment, the particle size of succinylated-ultrasonicated OVA (SU-OVA) had decreased by 3.0-5.1 times relative to that of S-OVA. Moreover, the net negative charge of S3U3-OVA had increased to the maximum value of - 35.6 mV. These changes contributed to the further enhancement in functional indicators. The unfolding of the protein structure and the conformational flexibility of SU-OVA were illustrated and compared with those of S-OVA via protein electrophoresis, circular dichroism spectroscopy, intrinsic fluorescence spectroscopy, and scanning electron microscopy. The dually modified OVA emulsion (S3U3-E) presented small droplets (243.33 nm), reduced viscosity, and weakened gelation behavior that were indicative of even distribution, which was visually proven by confocal laser scanning microscopy images. Furthermore, S3U3-E exhibited favorable stability, a particle size that was almost unchanged, and a low polydispersity index (<0.1) over 21 days of storage at 4 °C. The above results demonstrated that succinylation combined with ultrasonic treatment could be an effective dual modification method for enhancing the functional performance of OVA.

Ultrasonic process affecting interactions between sodium caseinate and whey proteins

Ultrasound has been widely explored for several applications, such as emulsification or structural modification of food materials such as proteins. In this work, the effect of ultrasound on the control of whey proteins (WPI) aggregation was evaluated in the presence of sodium caseinate (NaCas). Solutions of NaCas, WPI and both (1:1) were treated with ultrasound under different power and time conditions and were initially evaluated in terms of particle size distribution, charge density, pH and polyacrylamide gel electrophoresis. Three pairs of conditions were adopted to provide the same energy density - A1 (450 W / 300 s, 6750 MJ/m³), A2 (150 W / 900 s, 6750 MJ/m³), A3 (600 W / 300 s, 900 MJ/m³), A4 (202.5 W / 900 s, 9112.5 MJ/m³), A5 (742.5 W / 300 s, 11137.5 MJ/m³) and A6 (247.5 W / 900 s, 11137.5 MJ/m³). Best conditions of transmitted energy - A1, A3 and A5 - were studied for surface hydrophobicity, circular dichroism and infrared spectroscopy. The decrease of surface hydrophobicity of NaCas:WPI mixtures pointed to a protective effect of NaCas against WPI denaturation, confirmed by the presence of more ordered structures by FTIR analysis that were not observed in the absence of NaCas. Finally, the effect of these structural changes on the gelation capacity of the ultrasound-treated proteins was assessed. Ultrasound was able to reduce the stress at rupture from 1988.59 Pa (control) to 1655.31 Pa (A3) and 1871.24 Pa (A5), and more markedly increase the Young modulus from 113.69 kPa (control) to 243.30 kPa (A3) and 392.44 kPa (A5). This study identified that higher power values with shorter times were able to provide greater protein changes that affected gelation properties, showing that the modulation of ultrasound conditions can produce ingredients with different techno-functional properties.

Ultrasound-assisted processing: Changes in gel properties, water-holding capacity, and protein aggregation of low-salt Hypophthalmichthys molitrix surimi by soy protein isolate

The effects of ultrasound combined (25 kHz, 400 ± 20 W/L, ultrasonic time of 5, 10 and 15 min) with soy protein isolate processing on gelling properties of low-salt silver carp surimi, aggregation and conformation of myofibrillar protein were investigated. The results revealed that, compared with only adding soy protein isolate components, ultrasound-assisted soy protein isolate had a more obvious effect on the protein structure in low-salt surimi, leading to the decrease in α-helix and total sulfhydryl contents, and the increase in β-sheet content and protein solubility. As a result, more proteins participated in the formation of the gel network, and significant improvements in hardness, gel strength and water-holding capacity of the low-salt surimi gel were observed, while the myosin heavy chain in SDS-PAGE was weakened. The low-field NMR results showed that the initial relaxation time of T₂ was apparently shorter, the free water content decreased and the bound water content increased under the action of ultrasound. Scanning electron microscope observation found that the surimi gel treated by ultrasound exhibited smaller holes, and had a more stable and denser network structure. In conclusion, the results of our work demonstrated that ultrasound combined with soy protein isolate can significantly improve the gel quality properties of low-salt silver carp.

Effects of ultrasound assisted cell wall disruption on physicochemical properties of camellia bee pollen protein isolates

Camellia bee pollen protein isolates were extracted by cell wall disruption using ultrasonication, freeze-thawing, enzymatic hydrolysis, and their combinations. The effects of these methods on microstructure of cell wall, protein release, protein yield, physiochemical properties and structure of proteins were investigated. As compared with physical treatments (ultrasonication, freeze-thawing and their combination), the enzymatic hydrolysis significantly improved the yield of proteins, because it not only promoted the release of proteins from the inside of pollen, but also released proteins in pollen wall. The proteins extracted by enzymatic hydrolysis method also exhibited better solubility, emulsifying and gelation properties due to the partial hydrolysis of proteins by protease. In addition, when ultrasound was combined with freeze-thawing or enzymatic hydrolysis, it could further improve the yield of proteins and the functional properties of proteins, which was mainly related to the changes of protein structure induced by cavitation effect of ultrasound.

Comparison of Different Extraction Techniques and Conditions for Optimizing an HPLC-DAD Method for the Routine Determination of the Content of Chlorogenic Acids in Green Coffee Beans

Chlorogenic acids (CGAs) are the main phenolic compounds found in green coffee beans. They are receiving more attention recently due to the proven health and nutrition benefits they offer, in addition to their role as markers for coffee quality. A relatively large number of studies are reported in the literature that are based on the analysis of these compounds. However, very limited research is dedicated to the evaluation of the performance of the analytical methods used, particularly the extraction procedures. Therefore, this work was dedicated to the comparison of different extraction techniques and conditions in order to evaluate their influence on the measured content of the three main CGAs in green coffee beans, namely, chlorogenic acid (5-CQA), neochlorogenic acid (3-CQA) and cryptochlorogenic acid (4-CQA). Five simple extraction techniques with affordable equipment were compared in order to develop a routine method suitable for most analytical and food analysis laboratories. The compared extraction techniques provided relatively similar extraction efficiency for the three compounds. However, due to the merits of ultrasonic-assisted extraction as a fast, effective, green, and economical technique, this was selected by comparing the extraction variables and developing an optimized routine method. The extraction solvent, temperature, time, solid-to-solvent ratio, and grinding treatments were the variables that were investigated. The extraction solvent and the solid-to-solvent ratio were found to be the most influencing variables that may improve the extraction efficiency to up to 50%. Based on this thorough investigation, an optimized method for the routine determination of the content of chlorogenic acids in green coffee beans was developed. The developed method is simple, fast, and efficient in the extraction of the three main CGAs.

Effect of Corn Starch Granules on Stabilizing the Foam Structure of Ultrasonically Modified Whey Isolate Protein

In this study, the mechanism of ultrasound combined with corn starch granules (CSG) treatment improved the foam properties of whey protein isolates (WPI) and was systematically investigated. The results showed that ultrasound combined with corn starch granules treatment increased foam capacity and stability by 15.38% and 41.40%, respectively. Compared with the control group, corn starch granules enhanced the surface charge (52.38%) and system turbidity (51.43%), which certainly provided the necessary conditions for the improvement of foam stabilization stability. In addition, corn starch granules as microgel particles increased the mechanical properties of the interfacial protein film, thus delaying the instability of foam. This research would provide new insights into the design of new protein-based foam foods in the future food industry.

Improving the Functional and Sensory Properties of Cookies by Ultrasonic Treatment of Whey Proteins

The profiles of food products are one interesting link that adds a new functional component. Cookies became one of the remarkable foods as a result of their simple preparation, a protracted period, and a sensible acceptance by the population. The effects of sonication on physical and sensory characteristics of cookies to be enhanced were studied. The results showed that cookies prepared with 5 and 10% replacement of sonicated whey protein had significant differences in sensory evaluation especially crumb, but there were no significant differences in the physical characteristics, so we can conclude that sonication will improve sensory properties of cookies. Also, we can conclude that biscuit samples supplemented with 5 or 10% WPC were nutrient-rich. The results of the sensory evaluation showed that the cookie samples supplemented with 5% WPC performed better in most of the characteristics but decreased with an increase in the WPC level. The texture properties of the cookie samples indicated that the control cookies with WPC-supplemented cookies showed no significant differences in most studied properties. It can be concluded that the addition of sonicated whey protein enhanced the physiochemical and sensory properties of cookies.

Effects of High-Intensity Ultrasound Treatments on the Physicochemical and Structural Characteristics of Sodium Caseinate (SC) and the Stability of SC-Coated Oil-in-Water (O/W) Emulsions

The effects of high-intensity ultrasound treatment (0, 3, 6, 9 min) on physicochemical and structural characteristics of SC and the storage, thermal and freeze–thaw stability of SC O/W emulsions were investigated. The results showed that ultrasound treatment reduced the particle size of SC, although there were no obvious changes in zeta potential, profiles and weights. Ultrasound treatment improved surface hydrophobicity and fluorescence intensity of SC and changed ultraviolet–visible (UV–Vis) spectroscopy but had no influence on the secondary structure of SC. This indicates that ultrasounds might destroy the tertiary structure but leave most of the integral secondary structure. A scanning electron microscope (SEM) also showed that ultrasound-treated SC presented small aggregates and a loose structure. The physicochemical and structural changes of SC benefited the ability of protein adsorbing oil droplets and emulsion stability. Under stresses such as storage, thermal and freeze–thawing, the oil droplets of treated emulsions were still uniform and stable, especially at 6 min and 9 min. Overall, the high-intensity ultrasounds made the SC present small aggregates and a loose structure improving the SC O/W emulsions stability under storage, thermal and freeze–thawing environment and have great potential to stabilize the SC prepared O/W emulsions.

Effects of ultrasonic treatment on ovomucin: Structure, functional properties and bioactivity

The effects of ultrasonic treatment on the structure, functional properties and bioactivity of Ovomucin (OVM) were investigated in this study. Ultrasonic treatment could significantly enhance OVM solubility without destroying protein molecules. The secondary structure changes, including β-sheet reduction and random coil increase, indicate more disorder in OVM structure. After ultrasonic treatment, the OVM molecule was unfolded partially, resulting in the exposure of hydrophobic regions. The changes in OVM molecules led to an increase in intrinsic fluorescence and surface hydrophobicity. By detecting the particle size of protein solution, it was confirmed that ultrasonic treatment disassembled the OVM aggregations causing a smaller particle size. Field emission scanning electron microscopy (FE-SEM) images showed that ultrasonic cavitation significantly reduced the tendency of OVM to form stacked lamellar structure. Those changes in structure resulted in the improvement of foaming, emulsification and antioxidant capacity of OVM. Meanwhile, the detection results of ELISA showed that ultrasonic treatment did not change the biological activity of OVM. These results suggested that the relatively gentle ultrasound treatment could be utilized as a potential approach to modify OVM for property improvement.

Effects of Ultrasound versus Pasteurization on Whey–Oat Beverage Processing: Quality and Antioxidative Properties

The consumption of functional beverages is rapidly increasing. The improvement in the functional properties of whey after the application of ultrasound is due to the release of bioactive peptides that have antioxidant properties, among others. Bioactive peptides with antioxidant activity have also been found in oats, stimulating the study of whey beverages formulated with oats to obtain functional products. The aim of this study was to determine the influence of ultrasound (24 kHz) at 20 °C for 15 min at 23 W and 154 W on the quality and functional properties of whey–oat (50:50 v/v) beverages and compare it with pasteurization at 65 °C for 30 min (LTLT). Non-significant effect (p > 0.05) of ultrasound intensity (23 W and 154 W) was observed on the physicochemical characteristics and the proximal composition of the whey–oat beverages. The sonicated beverages showed a greater tendency to green and yellow color (p < 0.05), higher fat content (p < 0.05), and less ash and carbohydrates (p < 0.05) than the pasteurized beverage. The antioxidant activity of the mM Trolox equivalent/mL of the sonicated beverages was higher (p < 0.05) (4.24 and 4.27 for 23 W and 54 W, respectively) compared to that of the pasteurized beverage (4.12). It is concluded that ultrasound is superior to pasteurization in improving the antioxidant activity of whey–oat beverages without having a detrimental impact on the proximal composition and physicochemical quality. Future studies should evaluate more functional parameters and determine the shelf life of sonicated whey–oat beverages.

Study on model plant based functional beverage emulsion (non-dairy) using ultrasound - A physicochemical and functional characterization

This study reports the development of non-dairy functional beverage emulsion employing ultrasound (US) of 20 kHz at 130 W and 195 W at processing times of 2 to 8 min using chickpea milk extract and bioactive, flaxseed oil (4%). The pre-emulsion was formed with high shear homogenizer followed by main sonication process. The sonicated emulsions were stored at 4 ± 2 °C till 14 days and characterized for physicochemical and functional properties. A comparative study was carried out using conventional high shear homogenizer (UT) at 10,000 RPM for 5 min. Upon optimization, 130 W - 8 min, 195 W - 6 min and 195 W - 8 min sono-emulsions showed creaming stability of 100%; with particle sizes as 1.12, 0.97 and 0.78 µm; and zetapotential values as - 40.4 mV, -37.52 and -36.91 mV, respectively. The improvement in protein solubility by 86% proved the emulsifying capability of chickpea proteins, which had partially denatured upon physical effects of acoustic cavitation producing stable and finer emulsion droplets. The reduced sedimentation values of sonicated chickpea extract in comparison to UT showed improvement in physical stability of plant-based milk. Oxidative stability is observed for 130 W - 8 min sonicated emulsions with no change in conjugated dienes, indicating the absence of process generated free radicals. The US process did not have any effect on reduction of stachyose content. But extracted chickpea milk had lower amount of stachyose in comparison to raw chickpeas, reducing the flatulence problem, mainly due to adaptation of high temperature pressure cooking process.