Influence of high intensity ultrasound on microbial reduction, physico-chemical characteristics and fermentation of sweet whey

Enhancing Functional Properties and Protein Structure of Almond Protein Isolate Using High-Power Ultrasound Treatment

The suitability of a given protein for use in food products depends heavily on characteristics such as foaming capacity, emulsifiability, and solubility, all of which are affected by the protein structure. Notably, protein structure, and thus characteristics related to food applications, can be altered by treatment with high-power ultrasound (HUS). Almonds are a promising source of high-quality vegetable protein for food products, but their physicochemical and functional properties remain largely unexplored, limiting their current applications in foods. Here, we tested the use of HUS on almond protein isolate (API) to determine the effects of this treatment on API functional properties. Aqueous almond protein suspensions were sonicated at varying power levels (200, 400, or 600 W) for two durations (15 or 30 min). The molecular structure, protein microstructure, solubility, and emulsifying and foaming properties of the resulting samples were then measured. The results showed that HUS treatment did not break API covalent bonds, but there were notable changes in the secondary protein structure composition, with the treated proteins showing a decrease in α-helices and β-turns, and an increase in random coil structures as the result of protein unfolding. HUS treatment also increased the number of surface free sulfhydryl groups and decreased the intrinsic fluorescence intensity, indicating that the treatment also led to alterations in the tertiary protein structures. The particle size in aqueous suspensions was decreased in treated samples, indicating that HUS caused the dissociation of API aggregates. Finally, treated samples showed increased water solubility, emulsifying activity, emulsifying stability, foaming capacity, and foaming stability. This study demonstrated that HUS altered key physicochemical characteristics of API, improving critical functional properties including solubility and foaming and emulsifying capacities. This study also validated HUS as a safe and environmentally responsible tool for enhancing desirable functional characteristics of almond proteins, promoting their use in the food industry as a high-quality plant-based protein.

High-intensity ultrasound influences the probiotic fermentation of Baru almond beverages and impacts the bioaccessibility of phenolics and fatty acids, sensory properties, and in vitro biological activity

High-intensity ultrasound (HIUS, 20 kHz, 450 W, 6 min) was used as an alternative to the pasteurization of a water-soluble Baru almond extract (WSBAE). Then, probiotic fermented beverages (Lacticaseibacillus casei) were processed and evaluated during storage (7 °C, 28 days). Four formulations were prepared: RAW (untreated [no pasteurization or ultrasound] and unfermented WSBAE), PAST (pasteurized WSBAE fermented with probiotic), U-BEF (WSBAE added with probiotic, submitted to ultrasound, and fermented), and U-AFTER (WSBAE submitted to ultrasound, added with probiotic, and fermented). PAST and HIUS-treated beverages had similar microbiological quality. The PAST formulation showed decreased monounsaturated fatty acids, compromised health indices, and had the lowest consistency. U-AFTER showed higher concentrations of lactic and acetic acids, lower bioaccessibility for most phenolics and fatty acids, and reduced consumer acceptance. U-BEF had the fermentation time reduced by 13.64%, higher probiotic survival during storage and simulated gastrointestinal conditions, and higher bioaccessibility of phenolics and fatty acids during storage. Furthermore, it presented higher in vitro antidiabetic properties and improved consistency and stability. Finally, U-BEF had improved volatile compound composition, resulting in increased sensory acceptance and improved sensory properties. Our results indicate that the HIUS applied after probiotic addition may be a suitable alternative to pasteurization in the processing of fermented beverages, resulting in reduced fermentation times and improved technological, sensory, and biological properties.

Application progress of ultrasonication in flour product processing: A review

Flour products played a vital role in the global diet structure. With the increasing demand for dietary health and food standardization, the staple food of flour products made from coarse grains due to its unique flavor and rich nutrition has become a trend and is favored by consumers. However, the lack of gluten protein in the raw materials prevented the formation of a stable gluten network structure, leading to the deterioration of the quality of flour products. Ultrasonic treatment, as an innovative food processing technology, generated energy during the action of ultrasonic waves that had a positive impact on the texture, organizational structure, or flavor characteristics of food. That was of great significance for improving food production efficiency, improving food processing quality, and extending food shelf life. This article applied ultrasonic technology to the processing of flour products from the perspective of promoting fermentation and improving production efficiency of flour products. The cavitation effect of ultrasound promoted the formation of gluten network structure, improved the rheology properties of dough and the quality of flour products by promoting protein cross-linking, improving the foaming and emulsifying stability of gluten protein, and promoting the growth and reproduction of yeast. All reviewed studies indicate that ultrasound would be a promising technology for producing high-quality surface products under appropriate conditions.

Effects of ultrasonic processing on the quality properties of fortified yogurt

This study evaluated the effect of ultrasonic processing on functional yogurts fortified with banana-resistant starch (BRS) and green papaya powder (GPP). Ultrasonication technology (80% amplitude, 8 min at 20 kHz frequency) was utilized as an alternative to conventional thermal treatment (85 °C, 30 min) to improve functional yogurts' physical and textural properties. A total of 6 set-type yogurt groups were prepared by ultrasonication (UT) and conventional treatment (CT). Based on the textural studies and correlation (Pearson's) plots, fortified and UT samples were more stiff, firm, sticky, adhesive, and viscous (least elastic) compared to the CT samples. All of the tested yogurts maintained a remarkable number of viable colony counts (≥7.23 log CFU/mL) during the storage. Ultrasonication significantly (p < 0.05) changed the L, a*, and b* color values. The ultrasonic processing reduced whey syneresis and improved the water-holding capacity in fresh and stored yogurts. Further, it retained the fatty acid profile of fortified yogurts. However, ultrasonication negatively affected, i.e., reduced the total polyphenol content and antioxidant activity of yogurts as compared to the conventionally (thermal) treated counterparts. Overall, ultrasound technology can be a potential alternative to thermal treatment for the improved quality and safety of fortified yogurts.

Ultrasound-assisted production of alcoholic beverages: From fermentation and sterilization to extraction and aging

Ultrasound is sound waves above 20 kHz that can be used as a nonthermal ''green'' technology for agri-food processing. It has a cavitation effect, causing bubbles to form and collapse rapidly as they travel through the medium during ultrasonication. Therefore, it inactivates microorganisms and enzymes through cell membrane disruption with physicochemical and sterilization effects on foods or beverages. This emerging technology has been explored in wineries to improve wine color, taste, aroma, and phenolic profile. This paper aims to comprehensively review the research on ultrasound applications in the winery and alcoholic beverages industry, discuss the impacts of this process on the physicochemical properties of liquors, the benefits involved, and the research needed in this area. Studies have shown that ultrasonic technology enhances wine maturation, improves wine fermentation, accelerates wine aging, and deactivates microbes while enhancing quality, as observed with better critical aging markers such as phenolic compounds and color intensity. Besides, ultrasound enhances phytochemical, physicochemical, biological, and organoleptic properties of alcoholic beverages. For example, this technology increased anthocyanin in red wine by 50%. It also enhanced the production rate by decreasing the aging time by more than 90%. Ultrasound can be considered an economically viable technology that may contribute to wineries' waste valorization, resource efficiency improvement, and industry profit enhancement. Despite numerous publications and successful industrial applications discussed in this paper, ultrasound up-scaling and applications for other types of liquors need further efforts.

Encapsulation of Nutraceuticals in Yoghurt and Beverage Products Using the Ultrasound and High-Pressure Processing Technologies

Dairy and beverage products are considered highly nutritious. The increase demand for added nutritional benefits within the food systems consumed by the consumers paves the pathway towards fortifying nutraceuticals into these products. However, nutraceuticals are highly unstable towards harsh processing conditions. In addition, the safety of dairy and beverage products plays a very important role. Therefore, various heat treatments are in practice. As the heat-treated dairy and beverage products tends to illustrate several alterations in their organoleptic characteristics and nutritional properties, the demand for alternative non-thermal processing technologies has increased extensively within the food industry. Ultrasound and high-pressure processing technologies are desirable for this purpose as well as a safe and non-destructive technology towards encapsulation of nutraceuticals into food systems. There are benefits in implementing these two technologies in the production of dairy and beverage products with encapsulants, such as manufacturing high-quality products with improved nutritional value while simultaneously enhancing the sensory characteristics such as flavour, taste, texture, and colour and attaining the microbial quality. The primary objective of this review is to provide detailed information on the encapsulation of nutraceuticals and mechanisms involved with using US and HPP technologies on producing encapsulated yoghurt and beverage products.

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.

High-intensity ultrasound as pre-treatment in the development of fermented whey and oat beverages: effect on the fermentation, antioxidant activity and consumer acceptance

This study aimed to evaluate the effect of high-intensity ultrasound as pre-treatment in the development of fermented whey and oat beverages. Oat malt was produced, incorporated into a whey formulation (35, 50 and 65% v/v of whey) and ultrasonicated (at 40 kHz and 11 W/cm²) for 0, 3 or 10 min, prior to fermentation with L. casei 431. The treatments were identified as 35/65/0, 50/50/0, 65/35/0, 35/65/3, 50/50/3, 65/35/3, 35/65/10, 50/50/10 and 65/35/10, referring to the whey percentage, oat percentage, and the ultrasound time (min), respectively. The beverages 50/50/0 and 50/50/3 registered the highest (P < 0.05) growth with 1.96 and 2.00 log CFU ml, respectively. In general, the final average population of L. casei 431 was 7 to 8.86 log CFU/ml, being this adequate for a probiotic beverage. The highest antioxidant activity was found in the 35/65/3, 35/65/10, 50/50/3 and 50/50/10 beverages without difference (P < 0.05) among them. There was no effect of gender on the acceptance of the probiotic beverages. The best accepted beverage by women was 50/50/3 and both genders disliked the beverage 35/65/10. There was no relationship between the acceptance of the beverages and the consumers' habit by fermented milk beverages. No difference in the preference between the 50/50/0 and the 50/50/3 beverage was found. It is concluded that the probiotic beverage containing 50% whey and 50% oat and ultrasonicated for 3 min generated the highest levels of L. casei 431 growth, high antioxidant activity and good consumer acceptance and preference.

The Physicochemical, Microbiological, and Structural Changes in Beef Are Dependent on the Ultrasound System, Time, and One-Side Exposition

The effect of high-intensity ultrasound (HIU) system (bath, 37 kHz and 90 W/cm2; or probe, 24 kHz and 400 W) and application time (25 or 50 min, one-side exposition) on the properties of bovine Longissimus lumborum after 7 d of storage at 4 °C was studied. The bath system significantly increased the lightness of the muscle, while other color parameters (a*, b*, hue, and chroma) were not different from the control. The water holding capacity and shear force decreased significantly (3.1-5% and 0.59-0.72 kgf, respectively) in sonicated meat independently of the system, favoring the tenderization of the muscle after storage. Microstructural changes observed in the HIU-exposed surface provided evidence of a higher area of interfibrillar spaces (1813 vs. 705 µm2 in the control), producing tenderization of the muscle, compared with the control. HIU significantly increased counts of total aerobic and coliform bacteria, especially after 50 min of ultrasonication. HIU also increased lactic acid bacterial counts in the bath system. Single-sided muscle exposition to ultrasound may produce sufficient significant changes in muscle properties, which could decrease long treatment times that would be needed for the exposition of both sides. HIU in bath systems increases tenderness by modifying meat ultrastructure, with no significant changes in physicochemical parameters. Nevertheless, microbiological quality may need to be considered during the process due to a slight increase in bacterial counts.

Recent advances in the application of ultrasound in dairy products: Effect on functional, physical, chemical, microbiological and sensory properties

Alternative methods for improving traditional food processing have increased in the last decades. Additionally, the development of novel dairy products is gaining importance due to an increased consumer demand for palatable, healthy, and minimally processed products. Ultrasonic processing or sonication is a promising alternative technology in the food industry as it has potential to improve the technological and functional properties of milk and dairy products. This review presents a detailed summary of the latest research on the impact of high-intensity ultrasound techniques in dairy processing. It explores the ways in which ultrasound has been employed to enhance milk properties and processes of interest to the dairy industry, such as homogenization, emulsification, yogurt and fermented beverages production, and food safety. Special emphasis has been given to ultrasonic effects on milk components; fermentation and spoilage by microorganisms; and the technological, functional, and sensory properties of dairy foods. Several current and potential applications of ultrasound as a processing technique in milk applications are also discussed in this review.

Potential use of ultrasound to promote fermentation, maturation, and properties of fermented foods: A review

Conventional food fermentation is time-consuming, and maturation of fermented foods normally requires a huge space for long-term storage. Ultrasound is a technology that emerged in the food industry to improve the efficacy of food fermentation and presents great potentials in maturation of fermented foods to produce fermented foods with high quality. Proliferation of microorganisms was observed along with promoted enzyme activities and metabolic performance when treated by a short-term ultrasonication (<30 min) at a relatively low-power (≤100 W). Additionally, ultrasound at a high-power level (≥100 W) was highlighted to promote the maturation of fermented foods through promoting Maillard reaction, oxidation, esterification, and proteolysis. As a result of promoted fermentation and maturation, texture, color, flavor and taste of fermented foods were improved. All the reviewed studies have indicated that ultrasound at the proper conditions would be a promising technique to produce fermented foods with high-quality.

Combinations of emerging technologies with fermentation: Interaction effects for detoxification of mycotoxins?

Consumption of foods containing mycotoxins, as crucial groups of naturally occurring toxic agents, could pose significant health risks. While the extensive scientific literature indicates that prevention of contamination by toxigenic fungi is one of the best ways to reduce mycotoxins, detoxifying strategies are useful for improving the safety of food products. Nowadays, the food and pharmaceutical industries are using the concept of combined technologies to enhance the product yield by implementing emerging techniques, such as ultrasound, ohmic heating, moderate electric field (MEF), pulsed electric field (PEF) and high-pressure processing, during the fermentation process. While the application of emerging technologies in improving the fermentation process is well explained in this literature, there is a lack of scientific texts discussing the possibility of mycotoxin degradation through the interaction effects of emerging technologies and fermentation. Therefore, this study was undertaken to provide deep insight into applying emerging processing technologies in fermentation, mechanisms and the prospects of innovative combinations of physical and biological techniques for mycotoxins' detoxification. Among various emerging technologies, ultrasound, ohmic heating, MEF, PEF, and cold plasma have shown significant positive effects on fermentation and mycotoxins detoxification, highlighting the possibility of interactions from such combinations to degrade mycotoxins in foods.

Inclusion of Probiotics into Fermented Buffalo (Bubalus bubalis) Milk: An Overview of Challenges and Opportunities

Buffalo-milk-based dairy products provide various health benefits to humans since buffalo milk serves as a rich source of protein, fat, lactose, calcium, iron, phosphorus, vitamin A and natural antioxidants. Dairy products such as Meekiri, Dadih, Dadi and Lassie, which are derived from Artisanal fermentation of buffalo milk, have been consumed for many years. Probiotic potentials of indigenous microflora in fermented buffalo milk have been well documented. Incorporation of certain probiotics into the buffalo-milk-based dairy products conferred vital health benefits to the consumers, although is not a common practice. However, several challenges are associated with incorporating probiotics into buffalo-milk-based dairy products. The viability of probiotic bacteria can be reduced due to processing and environmental stress during storage. Further, incompatibility of probiotics with traditional starter cultures and high acidity of fermented dairy products may lead to poor viability of probiotics. The weak acidifying performance of probiotics may affect the organoleptic quality of fermented dairy products. Besides these challenges, several innovative technologies such as the use of microencapsulated probiotics, ultrasonication, the inclusion of prebiotics, use of appropriate packaging and optimal storage conditions have been reported, promising stability and viability of probiotics in buffalo-milk-based fermented dairy products.

Combination of liquid-phase pulsed discharge and ultrasonic for saponins extraction from lychee seeds

A skillfully combined method of liquid-phase pulsed discharge and ultrasonic (LPDU) had been developed for saponins extraction from lychee seeds. Single factor and response surface methods were used to optimize the system, respectively. The optimized conditions included 30% aqueous ethanol, 62.66 mL/g ratio of liquid to solid, 3 mm centre hole diameter of hollow electrode, 123 mL/min flow velocity, length of serpentine pipe of 15 cm, 276 W ultrasonic power, 47 °C ultrasonic temperature, and discharge voltage was fixed at 14 kV. Under these conditions, it obtained a maximum saponins yield of 51.30 ± 0.08 mg/g with 10 min, which was higher than those of LPD (42.33 ± 0.98 mg/g) with 24 min, ultrasonic assisted extraction (UAE) (41.80 ± 1.31 mg/g) with 30 min and maceration (38.72 ± 1.13 mg/g) with 180 min. Meanwhile, the energy consumption of LPDU was 7560 kJ/kg, which was notably lower than those of LPD (8820 kJ/kg), UAE (25875 kJ/kg) and maceration (10248 kJ/kg). We found that the saponin constituents of LPDU were similar to LPD, UAE, ME by HPLC content detection method, and found that LPDU had the highest degree of tissue damage after scanning electron microscope (SEM) comparison, which verified the reason for its high extraction efficiency. The results showed that LPDU was an effective technology for saponins extraction, which may be potentially applied in cosmetics, medicines and food chemistry.

Different Ultrasound Exposure Times Influence the Physicochemical and Microbial Quality Properties in Probiotic Goat Milk Yogurt

Despite goat milk having health benefits over cow milk, goat milk yogurt (GY) presents low consistency and viscosity, which reduces its overall acceptability by the consumer. Thus, new innovative methods can be an alternative to improve the quality of GY. Hence, this study aimed to investigate the effect of ultrasound (US) treatment with different sonication times on quality parameters of probiotic GY during refrigerated storage. US treatment was conducted at 20 KHz for 3, 6, and 9 min in yogurt. Lactobacillus bulgaricus and Lactobacillus acidophilus LA-5 were sensitive to US treatment, presenting a decrease in the yogurts stocked. This loss of viability led to reduced post-acidification due to smaller lactose metabolization in yogurt samples submitted to the US. Among tested treatments, the application of 6 min enhanced the apparent viscosity and consistency index of GY yogurts. In addition, this time also reduced tyramine and total biogenic amine (BAs) content. These findings suggest that 6 min of sonication is a promising way to improve the rheological properties and reduce the acidity and BAs content in GY. Further studies should be performed to optimize the US setting conditions to preserve the probiotic culture viability in yogurts.

Ultrasound-assisted fermentation for cider production from Lebanese apples

The present work studies the impact of low-intensity ultrasound (US) on Hanseniaspora sp. yeast fermentations. The effect of pulse duration and growth phase on US application was first evaluated using a synthetic medium. The optimal conditions were then applied to apple juice US-assisted fermentation. An US treatment chamber was first designed to allow the recycling of the culture medium. The optimal US pulse duration on the yeast growth rate was of 0.5 s followed by 6 s rest period, and during 6 h of both Lag and Log phases. These US parameters led to a faster consumption of glucose in the medium during the fermentation, compared to the untreated culture. The impact of US was also depending on the growth phase, showing higher sensitivity of the yeast to US during the Lag phase rather than the Log phase. US-assisted fermentation of apple juice showed a significant increase in biomass growth and glucose consumption, along with a significant decrease in the ethanol yield. The fastest growth kinetic (by 52%), and the highest ethanol reduction (by 0.55% (v, v)) were obtained for the treatment during the first 12 h of fermentation, thereby, the stationary phase was reached faster, and the maximum biomass growth rate was 10 folds higher compared to the untreated culture. The results obtained in this study demonstrated the promising efficiency of US-assisted fermentation in stimulating the biomass growth and reducing the ethanol content in alcoholic beverages.

The Effect of High-Intensity Ultrasound on the Physicochemical and Microbiological Properties of Mexican Panela Cheese

High-intensity ultrasound could be an alternative to pasteurization for cheeses made with fresh raw milk, the properties of which must be preserved as part of their intangible cultural heritage, such as Panela cheese in Mexico. This research aimed to study the effect of the amplitude (50% and 100%) and application time (0, 5, and 10 min) of ultrasound treatment of fresh raw milk, on the yield and microbiological and physicochemical qualities of Panela cheese after 24 h of storage at 4 °C. The yield was increased to 24.29% with 10 min of ultrasonication, although the amount of exudate was higher in the ultrasonic product than in the control (20.33%). As the ultrasonication time increased, the yellowness (b*) increased significantly, while the hue angle decreased (with values close to 90°), resulting in evident yellow tones in cheeses made with milk treated for 10 min. The pH significantly increased from 6.6 to 6.74 with 5 min of ultrasound, but decreased to 6.37 with 10 min of ultrasonication. Although no significant differences were found in fat content, the protein significantly increased with 5 min of sonication, but it decreased markedly when ultrasound was applied for 10 min. Ultrasound treatment with amplitudes of 50% effectively decreased the counts of coliform bacteria regardless of ultrasonication time. However, the mesophilic bacteria increased by a 0.9 log with an amplitude of 100% and 10 min treatment. The results showed that ultrasound improved the yield and microbial, nutritional, and physicochemical properties of Panela cheese.

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.

Ultrasound effects based on simulation of milk processing properties

Efficient reconstitution followed by fermentation of nonfat (skimmed) dry milk is one of the most important aspects in manufacturing of various dairy products. As a first stage, dry milk is normally being reconstituted using conventional approaches such as heating and stirring the mixture. Nevertheless, we demonstrated, that low-frequency (22 ± 1.65 kHz) ultrasound can be used as an alternative to the traditional methods of milk recovery. Low-frequency ultrasound was applied during pre-fermentation stage to improve the dispersity of the resulting milk product and to create good conditions for a post-ultrasound bacterial fermentation of milk. The applied ultrasound power was set in the range of 60-120 W/L. For the fermentation process we used: kefir fungi, fermenter of direct inoculation for yogurt LYOBAC YOYO and mixed culture for kefir LAT LC K. The effectiveness of ultrasound treatment was evaluated based on the accumulation of exopolysaccharides (EPS), vitamin C content, as well as antioxidant activity of the resulting milk product. The effect of ultrasound on microflora and the role of the specific types of bacteria such as Lactobacillus on the accumulation of biologically active compounds in the fermented milk products was studied with use of electron microscopy and MALDI - to FMS method. Overall, our results showed that reconstitution of dry milk with use of ultrasound improves further accumulation of biologically active compounds and rises the nutritional quality of the fermented product.

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.

Effects of ultrasound energy density on the non-thermal pasteurization of chocolate milk beverage

This study presents the emerging high-intensity ultrasound (HIUS) processing as a non-thermal alternative to high-temperature short-time pasteurization (HTST). Chocolate milk beverage (CMB) was subjected to different ultrasound energy densities (0.3-3.0 kJ/cm³), as compared to HTST pasteurization (72 °C/15 s) aimed to verify the effect of the HIUS processing on the microbiological and physicochemical characteristics of the beverage. The application of HIUS at an energy density of 3.0 kJ/cm³ was able to reduce 3.56 ± 0.02 logarithmic cycles in the total aerobic counts. In addition, the ultrasound energy density affected the physical properties of the beverage as the size distribution of fat globule and rheological behavior, as well as the chemical properties such as antioxidant activity, ACE inhibitory activity, fatty acid profile, and volatile profile. In general, the different energetic densities used as a non-thermal method of pasteurization of CMB were more effective when compared to the conventional pasteurization by HTST, since they improved the microbiological and physicochemical quality, besides preserving the bioactive compounds and the nutritional quality of the product.

Effect of Ultrasound Technology on Food and Nutritional Quality

Ultrasound technology has been successfully demonstrated for several food processing and preservation applications. The majority of food processing applications reported refer to liquid foods. Ultrasound has been applied to solid foods in some niche applications, e.g., tenderization of meat, mass transfer applications, and drying. Similar to any other technology, ultrasound also has some positive and negative effects on food quality depending on the application and processing conditions employed. This chapter outlines various applications of ultrasound to food and its effect on food and nutritional quality.

Ultrasound technology for food fermentation applications

Fermentation processes involve the participation of enzymes and organic catalysts, generated by range of microorganisms to produce chemical transformations. Ultrasound can be used in such processes to either monitor the progress of fermentation or to influence its progress. High frequency ultrasound (>2MHz) has been extensively reported as a tool for the measurement of the changes in chemical composition during fermentation providing real time information on reaction progress. Low frequency ultrasound (20-50kHz) can influence the course of fermentation by improving mass transfer and cell permeability leading to improved process efficiency and production rates. It can also be used to eliminate micro-organisms which might otherwise hinder the process. This review summarises key applications of high and low frequency ultrasound in food fermentation applications.

Intensified recovery of valuable products from whey by use of ultrasound in processing steps - A review

The current review focuses on the analysis of different aspects related to intensified recovery of possible valuable products from cheese whey using ultrasound. Ultrasound can be used for process intensification in processing steps such as pre-treatment, ultrafiltration, spray drying and crystallization. The combination of low-frequency, high intensity ultrasound with the pre-heat treatment minimizes the thickening or gelling of protein containing whey solutions. These characteristics of whey after the ultrasound assisted pretreatment helps in improving the efficacy of ultrafiltration used for separation and also helps in preventing the blockage of orifice of spray dryer atomizing device. Further, the heat stability of whey proteins is increased. In the subsequent processing step, use of ultrasound assisted atomization helps to reduce the treatment times as well as yield better quality whey protein concentrate (WPC) powder. After the removal of proteins from the whey, lactose is a major constituent remaining in the solution which can be efficiently recovered by sonocrystallization based on the use of anti-solvent as ethanol. The scale-up parameters to be considered during designing the process for large scale applications are also discussed along with analysis of various reactor designs. Overall, it appears that use of ultrasound can give significant process intensification benefits that can be harnessed even at commercial scale applications.