High-intensity Ultrasound Processing Research Articles

Impact of ultrasound processing of açai juice containing complex carbohydrates in human intestinal microbiota composition and metabolite production

The present study evaluated the impact of high-intensity ultrasound processing of potentially prebiotic açai juice containing complex carbohydrates (dextran and oligosaccharides) on human gut microbiota after in vitro colonic fermentation. The juice was subjected to an in vitro simulated digestion and human fecal fermentation. HPLC quantified the metabolites produced during fecal fermentation, and the 16 S rRNA sequencing evaluated the microbiota change. The gluco-oligosaccharides and dextran were resistant to in vitro digestion and promoted the fecal microbiota production of short-chain fatty acids (SCFAs). The sonicated juice markedly increased propionic and butyric acid production, reaching 11 g/L and 4 g/L, respectively. The potentially prebiotic açai juice improved the richness (25%) and diversity (22%) of the fecal microbiota, and the ultrasound processing increased richness (12%) compared to non-sonicated juice, which may contribute to overall host health. The study demonstrated that açai juice containing gluco-oligosaccharides and dextran has a potential prebiotic effect. Incorporating this juice into the diet might promote gut-beneficial bacterial growth, improving the gut microbiota and the health-promoting metabolites.

Thermal Treatment and High-Intensity Ultrasound Processing to Evaluate the Chemical Profile and Antioxidant Activity of Amazon Fig Juices

The present paper evaluated the influence of heat treatment (HT) and high-intensity ultrasound (HIUS) on the chemical profile of the Amazon fig (Ficus subapiculata, Moraceae) juices. Antioxidant activity, quantification of carotenoids, total phenolic compounds (TPC), pH, titratable acidity, soluble solids, color and chemical profile (NMR) were evaluated. Treatments did not change the pH (3.4–3.5), titratable acidity (0.044–0.048%) and soluble solids (2.3–2.4 °Brix). The highest antioxidant activity (DPPH, ABTS) and TPC were presented by the HT-treated juice, which was equivalent to 1235 ± 11 µM TE, 1440 ± 13 µM TE and 312 ± 5 mg GAE mL−1, respectively. The treatments influenced the color luminosity according to the L* and a* parameters, while the b* parameter showed no significant change. The L* parameter was elevated in all treated samples compared to the control sample. Analyzing the parameter a* f, it was verified that the sample with thermal treatment (HT) was different from the control sample, but presented similarity with the samples of the HIUS processes. The 1H NMR spectra of the juices showed similar chemical profiles in all treatments. The compounds α-glucose, β-glucose, fructose, citric, malic, quinic, and p-hydroxybenzoic acids were identified. The HT treatment presented higher efficiency to extract the antioxidant compounds from fig juices. The HIUS treatments with constant energy density also improved the tolerance of the antioxidant compounds, especially in conditions of higher potency and reduced time. Future studies will be devoted to carry out microbiological analysis and evaluate the stability of treated juices.

Inulin-type dietary fiber stability after combined thermal, mechanical, and chemical stresses related to ultrasound processing of prebiotic apple beverage

Inulin-type fructans are promising prebiotic dietary fibers added to foods and beverages to aggregate functional properties. In this regard, this study examined the chemical and physical stability of inulin after thermal, mechanical, and chemical stress conditions provided by high-intensity ultrasound treatment. The objective was to investigate the behavior of the inulin molecular structure and its technological issues under high-energy processing to understand the feasibility of adding inulin to new products with health benefits. Temperature monitoring during high-intensity ultrasound processing was crucial because high temperatures of up to 82 ± 1 °C were reached using short processing times of up to 5.48 min. Despite the temperature rise, ultrasound specific energies of 30, 120, 210, and 300 J/g did not affect the pH, soluble solid content, total phenolic content, antioxidant activity, and sugar content of the inulin-enriched apple beverage. In addition, the ultrasound processing stresses promoted by acoustic cavitation did not modify the profile and content of the short chain inulin added to the apple juice. The specific energy of 300 J/g contributed to the physical stability of the prebiotic apple beverage because this high-energy condition inhibited inulin precipitation producing a less cloudy product. Inulin was stable to high-energy ultrasound treatment because its molecular integrity was preserved. Moreover, the nutritional and bioactive compounds of the apple beverage were stable against acoustic cavitation-induced degradation. On the other hand, inulin precipitated in the aqueous solution after cooling of samples treated up to 210 J/g clouding the apple beverage. Indeed, high-intensity ultrasound processing enhanced the technological attributes of the prebiotic beverage, preventing its clouding due to inulin precipitation. Sonication treatment increased the physical stability of the beverage because it increased the magnitude of zeta potential.

High-Intensity Ultrasound Processing Enhances the Bioactive Compounds, Antioxidant Capacity and Microbiological Quality of Melon (Cucumis melo) Juice.

The bioactive compounds, antioxidant capacity and microbiological quality of melon juice processed by high-intensity ultrasound (HIUS) were studied. Melon juice was processed at two ultrasound intensities (27 and 52 W/cm2) for two different processing times (10 and 30 min) using two duty cycles (30 and 75%). Unprocessed juice was taken as a control. Total carotenoids and total phenolic compounds (TPC) were the bioactive compounds analyzed while the antioxidant capacity was determined by DPPH, ABTS and FRAP assays. The microbiological quality was tested by counting the aerobic and coliforms count as well as molds and yeasts. Total carotenoids increased by up to 42% while TPC decreased by 33% as a consequence of HIUS processing regarding control juice (carotenoids: 23 μg/g, TPC: 1.1 mg GAE/g), gallic acid and syringic acid being the only phenolic compounds identified. The antioxidant capacity of melon juice was enhanced by HIUS, achieving values of 45% and 20% of DPPH and ABTS inhibition, respectively, while >120 mg TE/100 g was determined by FRAP assay. Further, the microbial load of melon juice was significantly reduced by HIUS processing, coliforms and molds being the most sensitive. Thus, the HIUS could be an excellent alternative supportive the deep-processing of melon products.

The influence of high pressure homogenization and high-intensity ultrasound on the functional properties of whey-protein/canola oil nanoemulsions during storage

The current work was conducted in order to explore the influence of two non-thermal technologies (high pressure processing (HPH) and high-intensity ultrasound (HIU) on the droplet size, turbidity and lipid oxidation of whey protein / canola oil nanoemulsions (WPN) during a week. The outcomes exhibited that the HIU process have a significant impact on both droplet size and lipid oxidation (p<0.05) of WPNs. A smaller droplet size was obtained for HPH treated WPNs compared to the control (untreated) WPNs. On the other hand, the smallest droplet sizes were obtained for the samples exposed to 10 min HIU at 100% amplitude (614.7 nm). The same sample also showed the least lipid oxidation during 7 days of storage (124 mmol/kg). There is a positive relationship between the variables of droplet sizes and turbidities. All HIU-treated WPN samples exhibited less turbidity and smaller droplet size where the control WPN samples demonstrated most turbid structure (5.97) with the biggest droplet sizes (985.4 nm). Similar positive relationship was also figured out between the variables of droplet size and lipid oxidation. All HIU-treated WPN samples exhibited less lipid oxidation and smaller droplet size where the control WPN samples demonstrated most lipid oxidation with the biggest droplet sizes.

High‐intensity ultrasound processed acerola juice containing oligosaccharides and dextran promotes Lacticaseibacillus casei NRRL B‐442 growth

SummaryIn the present study, a prebiotic acerola juice containing gluco‐oligosaccharides and dextran was produced and processed by high‐intensity ultrasound (HIUS). After a simulated in vitro digestion, the gluco‐oligosaccharides and dextran maintained 90% and 80% of their initial concentration in all prebiotic’s juices. At the same time, Vitamin C and phenolic compounds concentration increased significantly by 19% and 7% (P < 0.05). After the in vitro digestion, the prebiotic juice HIUS processed by 10 min showed the highest increase in gluco‐oligosaccharides and bioactive compound concentrations. The HIUS processing imparted some dextran hydrolysis and improved its fermentability by Lacticaseibacillus casei. Gluco‐oligosaccharides were extensively consumed as substrate in simulated intestinal conditions, promoting the L. casei NRRL B‐442 growth and production of organic acids and short‐chain organic acids. The prebiotic juice HIUS processed for 6 min showed the best responses regarding the metabolism of L. casei NRRL B‐442. The results showed high‐intensity ultrasound processed acerola juices containing gluco‐oligosaccharides and dextran as a prebiotic food.

Ultrasound-assisted production of emulsion-filled pectin hydrogels to encapsulate vitamin complex: Impact of the addition of xylooligosaccharides, ascorbic acid and supercritical CO2 drying

Emulsion-filled hydrogels are a promising approach to encapsulate lipophilic bioactive compounds and protect them throughout storage. This study aimed to investigate the chemical stability of a vitamin complex (β-carotene, cholecalciferol, α-tocopherol, and ascorbic acid) in lentil protein emulsion-filled pectin hydrogel produced using high-intensity ultrasound (HIUS) as homogenization technique. The impacts of HIUS nominal power, the addition of xylooligosaccharides (XOS) and ascorbic acid on the viscoelastic properties, chemical stability, microstructure, color, lipid oxidation and antioxidant activity of the formed emulsion-filled hydrogels were evaluated. Overall, the hydrogels showed shear-thinning behavior. The addition of ascorbic acid had no significant effect on the rheological properties. The samples processed at 900 W for β-carotene and ascorbic acid contents and 600 W for cholecalciferol and α-tocopherol contents after 21 days of storage had maximum retention capacity. The presence of ascorbic acid contributed to the improved antioxidant activity, thus reducing the lipid oxidation in the samples. The FT-IR spectra showed no conformational difference before and after HIUS processing, indicating no degradation of the vitamin structures and XOS used. The emulsion-filled hydrogels were then dried to form aerogels using supercritical carbon dioxide (SC-CO2) technology. The concentration of pectin used influenced the drying of aerogels. Emulsion-filled hydrogels and aerogels with improved stability of the complex vitamins were produced.

Raw milk processing by high‐intensity ultrasound and conventional heat treatments: Microbial profile by amplicon sequencing and physical stability during storage

This study aimed to evaluate the effects of conventional heat treatments (high‐temperature–short‐time and low‐temperature–low‐time) and high‐intensity ultrasound (HIUS) on the physical stability and bacterial diversity of whole milk during refrigerated storage. HIUS processing used an energy density of 3 kJ/mL and an ultrasound intensity of 90 W/cm2. The most abundant bacterial genera found in raw milk were Acinetobacter and Pseudomonas. After processing and storage for 7 days, Acinetobacter, Kluyvera and Serratia were the dominant genera in almost all samples, and Pseudomonas was the most abundant in HIUS‐processed milk. Only the HIUS process reduced the fat droplet size (<1 µm), providing better physical stability during the storage period.

High-intensity ultrasound processing of baobab fruit pulp: Effect on quality, bioactive compounds, and inhibitory potential on the activity of α-amylase and α-glucosidase

Effect of high-intensity ultrasound (HIU) compared with thermal treatments on baobab fruit pulp (BFP) quality and bioactive properties were investigated. HIU treatments, particularly at intensities of 687.5 W/cm2 for 5 min, and 344 W/cm2 for 15 min significantly (p < 0.05) increased the cloudiness index, ascorbic acid (AA) retention, total phenolic and flavonoid contents, and antioxidant capacity besides a more potent α-amylase and α-glucosidase inhibition relative to thermally treated samples. Moreover, the physicochemical parameters, colour index, and browning index were maintained with HIU besides lower 5-hydroxymethylfurfural values than thermal processing. HPLC analysis revealed that the content of most phenolic compounds was the highest in HIU treatments besides a 235–256% increase in procyanidin C1 compared with control samples. The AA retention following HIU treatments was 87.62–102.86% compared to 30.47–61.90% in thermally treated samples. Our analyses portrayed ultrasound as a feasible alternative to conventional thermal processing of BFP.

High-intensity ultrasound-assisted recovery of anthocyanins from jabuticaba by-products using green solvents: Effects of ultrasound intensity and solvent composition on the extraction of phenolic compounds

This study proposes an update for the jabuticaba processing chain to obtain valuable coproducts from jabuticaba peels. High-intensity ultrasound (HIUS) technology was evaluated as a more efficient extraction process to obtain two high added-value coproducts: pectin and an anthocyanins-rich extract. The HIUS-assisted extraction of bioactive compounds like anthocyanins from the jabuticaba peels was evaluated. The effects of ultrasound intensity (1.1, 3.7, 7.3, and 13.0 W/cm2) and solvent composition concerning water/ethanol ratio (0, 25, 50, 75, and 100 g water/100 g) were examined. One-step HIUS processing promoted the best recovery of bioactive compounds at an ultrasound intensity of 3.7 W/cm2 and 50 g water/100 g, thus proofing the interaction between ultrasound intensity and the solvent composition has a strong influence on the extraction efficiency of the groups of compounds studied and in the jabuticaba peel antioxidant potential. The confocal laser scanning microscopy confirmed bioactive compounds' exhaustion in the dried jabuticaba peel after the HIUS processing, proving its best recovery. The jabuticaba peel extract exhibited an intense reddish color typical of anthocyanin-rich products at acid pH (4.5). The HIUS technology turned out a promising way to recover these valuable phenolic compounds as a quick, relatively inexpensive, and simple technology that improves the yields and decreases the costs and environmental impacts compared to conventional extraction processes.

Effects of high-intensity ultrasound processing on the physiochemical and allergenic properties of shrimp

Shrimp is a common seafood with high nutritional value and delicious flavor. However, many individuals are allergic to shrimp, but no therapies have been provided until now. The aim of this study was to evaluate the impacts of the high-intensity ultrasound processing (0, 5, 10, 15, 20 min, at room temperature) on the physiochemical and allergenic properties of shrimp samples. The results indicated allergenicity decreased with increasing treatment time, and the best hypoallergenic effect showed at 20 min with a 76% reduction of tropomyosin. At 20 min, the total soluble protein content decreased by 28.26%, while the in vitro digestibility, peptide content, total antioxidant capacity strengthened by 7.53%, 0.81%, and 71.29%, respectively. β-Sheets and α-helices increased with processing time, accompanied by the reduction of turns and unordered conformations determining by Fourier-transform infrared spectroscopy. More fragments, strips, and holes were observed after 20 min, which indicated the physical essence of ultrasound treatment in improving the extraction of bioactive molecules. Industrial relevanceThe high-intensity ultrasound as a novel non-thermal processing technique exhibits great potential in reducing the allergenicity of food products. In comparison to thermal processing techniques, it consumes less energy and has a higher mass transfer rate without altering the fundamental properties of foods. Shrimp allergens can be efficiently modified or even eliminated after the optimal condition of ultrasound treatment. The sensory and nutritional properties of shrimp can be retained to meet the marketing requirements for consumers. Therefore, the manufacture of hypoallergenic shrimps with high quality will be one of the most popular products in the future. The findings in this study provide a better understanding of ultrasound application in both lowering allergenicity and retaining the nutritional characteristics of shrimp.

High-intensity ultrasound-assisted recovery of cinnamyl alcohol glycosides from Rhodiola rosea roots: Effect of probe diameter on the ultrasound energy performance for the extraction of bioactive compounds

High-intensity ultrasound (HIUS) energy performance was evaluated using different probe diameters (10 and 20mm) and specific energies (0.5, 1.0, 3.0, and 5.0kJ/g) to recover rosavin and rosin from Rhodiola rosea roots. Also, intensified HIUS process conditions (5, 10, 15, and 20kJ/g) assisted by a cold bath were studied. HIUS energy performance depended on probe diameter at the same nominal power. The larger diameter probe was more energy-efficient, however, the smaller diameter had more ultrasonic intensity (W/cm2). The diameters evaluated did not influence the extraction yields, however, the increase of the HIUS specific energy from 0.5 to 5.0kJ/g increased phenolic compounds content, antioxidant activities, and rosavin and rosin yields. The HIUS process intensification confirmed that the main extraction mechanism was diffusion and the role of the ultrasound was to increase the diffusion coefficients by increasing the turbulence in the liquid medium due to acoustic cavitation.

High-intensity ultrasound processing of kiwifruit juice: Effects on the microstructure, pectin, carbohydrates and rheological properties

This study aimed to evaluate the influences of high-intensity ultrasound on the physiochemical properties of kiwifruit juice. Results reported high-intensity ultrasound processing significantly enhanced the color attributes, cloudiness, and sugars of kiwifruit juice. Further, the shear stress, apparent viscosity, storage and loss modulus was increased with the rise of processing time. However, a significant degradation in the nanostructure of water-soluble pectin and suspended particles in ultrasound treated kiwifruit juice was observed. In addition, ultrasound processing resulted in the rupture of cell wall causing the dispersion of the intracellular components into juice while higher damage in the cellular structure was observed by increasing the processing time. These structural changes reveal the physical mechanism of ultrasound in improving the rheological properties, color attributes, cloudiness, and water-soluble pectin of kiwifruit juice. Altogether these findings suggest that high-intensity ultrasound has an enormous potential to improve the physical properties of kiwifruit juice.

Xylooligosaccharides chemical stability after high-intensity ultrasound processing of prebiotic orange juice.

The effects of the high-intensity ultrasound (HIUS) technology at the nominal powers of 300, 600, 900, and 1200W were evaluated on the chemical stability of xylooligosaccharides (XOS) used to enrich orange juice. The ultrasound energy performance for each nominal power applied to the XOS-enriched orange juice was determined by calculating acoustic powers (W), HIUS intensity (W/cm2), and energy density (kJ/mL). Physicochemical properties (pH and soluble solid content), organic acid content (ascorbic, malic, and citric acids), total phenolic content (TPC), antioxidant activity by the FRAP (Ferric reducing ability of plasma) method, sugar (glucose, fructose, and sucrose), and XOS (xylobiose, xylotriose, xylotetraose, xylopentaose, and xylohexaose) content were determined. The pH and soluble solid content did not change after all HIUS treatments. The HIUS process severity was monitored by quantifying ascorbic acid content after the treatments. A significant linear decrease in the ascorbic acid content was observed in prebiotic orange juice with the HIUS process intensification by increasing nominal power. The malic acid and citric acid contents had similar behavior according to the HIUS process intensification. The nominal power increase from 300 to 600W increased the concentration of both organic acids, however, the intensification up to 1200W reduced their concentration in the functional beverage. The TPC and FRAP data corroborated with the results observed for the ascorbic acid content. However, the HIUS processing did not alter sugar and XOS contents. The XOS chromatographic profiles were not modified by the HIUS treatment and presented the same amount of all prebiotic compounds before and after the HIUS treatment. Overall, HIUS technology has been evaluated as a promising stabilization technique for prebiotic beverages enriched with XOS due to their high chemical stability to this emerging technology under severe process conditions.

Clove essential oil emulsion-filled cellulose nanofiber hydrogel produced by high-intensity ultrasound technology for tissue engineering applications.

High-intensity ultrasound (HIUS) was used to produce emulsion-filled cellulose nanofiber (CNF) hydrogel using clove essential oil (0.1, 0.5 and 1.0 wt%) as dispersed phase towards tissue engineering applications. The novel encapsulating systems obtained using HIUS specific energy at the levels of 0.10, 0.17, and 0.24 kJ/g were characterized by oil entrapment efficiency, microstructure, water retention value, color parameters, and viscoelastic properties. Freeze-dried emulsion-filled CNF hydrogels were characterized by porosity and swelling capacity. In addition, human gingival fibroblast cell cytocompatibility tests were performed to evaluate their potential applications as tissue engineering scaffold. The clove essential oil content strongly affected the oil entrapment efficiency, water retention value, color difference and whiteness of the prepared emulsion-filled CNF hydrogel. And, the HIUS energy only affected the yellowness of the emulsion-filled CNF hydrogel. Via HIUS processing, the CNF hydrogel successfully acted as a continuous phase in the emulsion-filled gel system with maximum oil entrapment efficiency of 34% when 0.5 wt% clove essential oil was added to the system. The encapsulating systems had predominantly gel-like property with maximum elastic modulus of 411 Pa. Furthermore, the emulsion-filled CNF hydrogels with the addition of clove essential oil up to 0.5 wt% indicated good cell viability rates (74-101%) to human gingival fibroblast cells. The newly developed clove essential oil emulsion-filled CNF hydrogel shows desirable cytocompatibility characteristics and can be considered as an alternative scaffold for tissue engineering applications.

High-intensity ultrasound: A novel technology for the development of probiotic and prebiotic dairy products.

High-intensity ultrasound (HIUS) can be used as a mild-preservation technology in dairy products, due to its ability to inactivate pathogenic microorganisms and enzymes. In addition, it can result in physical and chemical alterations in the products and has impact on the probiotic viability and metabolic activity. This review provides an overview of the effects of HIUS on dairy products manufactured with probiotics and prebiotics. Furthermore, it presents perspectives of HIUS application on paraprobiotics and postbiotics products. HIUS has been proven to be a potential technology and its application to fermented dairy products can result in shorter processing time, increased probiotic viability, and products with low lactose content, higher oligosaccharides concentration, less undesirable taste (lower propionic and acetic acids content) and reduced ingredients (no need of prebiotic addition or β-galactosidase inclusion). In cheeses, HIUS can reduce the ripening time and accelerate proteolysis, resulting in products with better sensory, textural and nutritional (bioactive peptides) characteristics. Furthermore, it can change the prebiotic structure, facilitating the access for the probiotics. The impact of the HIUS is highly dependent on the process parameters (frequency, power, processing time, pulse mode and duration), type of probiotic culture and food composition. Therefore, HIUS process parameters must be precisely quantified and controlled. The HIUS can also be applied to the inactivation of probiotic cultures and development of paraprobiotic products or to the improvement in the production of soluble factors (postbiotics) with health effects. Further researches should be conducted to evaluate the efficiency of this methodology in the cases of paraprobiotic and postbiotic products.

High-intensity ultrasound processing of kiwifruit juice: Effects on the ascorbic acid, total phenolics, flavonoids and antioxidant capacity

The objective of the study was to investigate the effect of high-intensity ultrasound processing (0, 4, 8, 12 and 16 min at 400 W, 25 kHz frequency) on the total phenolics, flavonoids, ascorbic acid, and antioxidant capacity of kiwifruit juice. The microstructural characteristics of treated kiwifruit samples were also measured. The results reveal that the total phenolics, flavonoids and antioxidant capacity of treated samples (16 min) significantly increased by 108.65%, 105.56%, and 65.67%, respectively compared to the control group. However, 16-min ultrasound treatment significantly decreased the total protein and ascorbic acid in kiwifruit juice. Microstructure measurement states the formation of microscopic channels or holes, cell walls rupture, torn and tissue distortion after ultrasound processing, which reveals the physical mechanism of ultrasound treatment in improving the extraction of bioactive molecules. These findings indicate that high-intensity ultrasound has an enormous potential to increase these bioactive molecules and antioxidants capacity of kiwifruit samples.

Obtaining a novel mucilage from mutamba seeds exploring different high-intensity ultrasound process conditions

We evaluated the effect of ultrasonic power (200–600 W) and process time (1–7 min) on the recovery of a novel polysaccharide from mutamba (Guazuma ulmifolia Lam.) seeds applying high-intensity ultrasound. Ultrasound process conditions intensification gradually was removing the mucilage layer around the hydrated seeds. Then, the scanning electron micrographs showed that the mucilage was removed completely at the highest applied energy density (10,080 J/mL). Although the colour of mutamba seed mucilage (MSM) have been changed due to increase of energy density, it not affects its practical use because the MSM can be purified to remove impurities. The results obtained in this study demonstrated that the ultrasound process conditions intensification did not affect the primary structure of MSM according to ζ-potential, FTIR spectrum, and monosaccharide residues data. In conclusion, ultrasound process conditions intensification allows the full recovery of the MSM at a short process time (7 min) without altering its quality and the primary structure.

Effects of high-intensity ultrasound process parameters on the phenolic compounds recovery from araticum peel

In this work, we investigated the effects of the nominal ultrasonic power (160–640 W) and process time (0.5–5.0 min) on the phenolic compounds recovery and antioxidant activity from araticum peel. The individual and synergistic effects of the process variables on the phenolic recovery were estimated using a full factorial experimental design. Operating at high nominal ultrasonic powers was possible to obtain high phenolic yields and antioxidant activities at short process times (≤5 min). The HPLC-ESI-QTOF-MS/MS analysis revealed that the araticum peel sample possessed 142 phytochemicals, 123 of which had not been reported in the literature for this raw material yet. The most abundant phenolic compounds recovered were epicatechin, rutin, chlorogenic acid, catechin and ferulic acid. Thus, high-intensity ultrasound technology proved to be a simple, efficient, fast and low environmental impact method for obtaining phenolic compounds from araticum peel. In addition, araticum peel showed to be a promising source bioactive natural phenolics for further applications in the food, nutraceutical, cosmetic and pharmaceutical industries.

Physicochemical changes and microbial inactivation after high-intensity ultrasound processing of prebiotic whey beverage applying different ultrasonic power levels

In this work, we investigated the effects of the ultrasonic power (0, 200, 400 and 600 W) on non-thermal processing of an inulin-enriched whey beverage. We studied the effects of high-intensity ultrasound (HIUS) on microbial inactivation (aerobic mesophilic heterotrophic bacteria (AMHB), total and thermotolerant coliforms and yeasts and molds), zeta potential, microstructure (optical microscopy, particle size distribution), rheology, kinetic stability and color. The non-thermal processing applying 600 W of ultrasonic power was comparable to high-temperature short-time (HTST) treatment (75 °C for 15 s) concerning the inactivation of AMHB and yeasts and molds (2 vs 2 log and 0.2 vs 0.4 log, respectively), although HIUS has reached a lower output temperature (53 ± 3 °C). The HIUS was better than HTST to improve beverage kinetic stability, avoiding phase separation, which was mainly attributed to the decrease of particles size, denaturation of whey proteins and gelation of polysaccharides (inulin and gellan gum). Thus, non-thermal processing by HIUS seems to be an interesting technology for prebiotic dairy beverages production.