Ultrasound stabilization of raw milk: Microbial and enzymatic inactivation, physicochemical properties and kinetic stability

The aim of this study was to evaluate the effects of non-thermal and thermal high-intensity ultrasound (HIUS) treatment on the microbial and enzymatic inactivation, physicochemical properties, and kinetic stability of the raw milk by applying different energy densities (1, 3, 5, and 7 kJ/mL). Two HIUS treatments were evaluated based on different nominal powers, named HIUS-A and HIUS-B, using 100 W and 475 W, respectively. HIUS-A treatment was non-thermal processing while HIUS-B was a thermal treatment only for the energy densities of 5 and 7 kJ/mL since the final temperature was above 70 °C. The HIUS-B treatment showed to be more efficient. Log reductions up to 3.9 cycles of aerobic mesophilic heterotrophic bacteria (AMHB) were achieved. Significant reductions of the fat globule size, with diameters lower than 1 µm, better color parameters, and kinetic stability during the storage were observed. Also, HIUS-B treatment inactivated the alkaline phosphatase and lactoperoxidase. The HIUS-B treatment at 3 kJ/mL worked below 57 °C being considered a border temperature since it did not cause unwanted physicochemical effects. Furthermore, a microbial inactivation of 1.8 ± 0.1 log cycles of AMHB was observed. A proper inactivation of only the Alkaline phosphatase and a significant reduction of the fat globules sizes, which kept the milk kinetically stable during storage was achieved.

Interactions of β-carotene with WPI/Tween 80 mixture and oil phase: Effect on the behavior of O/W emulsions during in vitro digestion

This study investigated the impact of adding β-carotene on the structure of fresh O/W emulsions with different oil phase (sunflower oil-LCT or NEOBEE®1053-MCT) and emulsifiers (WPI, Tween 80 - T80 or WPI/T80 mixture). In this sense, the behavior of emulsions through the gastrointestinal tract, the stability and bioaccessibility of β-carotene were also assessed. The β-carotene reduced the interfacial tension of the LCT/MCT-water systems. The addition of β-carotene promoted an increase of viscoelasticity of LCT/MCT-T80 (0.5%WPI/0.5%T80 and 1%T80 w/w) interfaces, but an increase of WPI content reduced the viscoelasticity of interfacial layers (LCT/MCT-1% WPI). These changes in the interface properties influenced the mean droplet size and ζ-potential of the fresh emulsions. LCT systems presented similar bioaccessibility/stability of β-carotene. However, β-carotene entrapped within protein-coated MCT droplets was more stable than within T80-MCT systems. Our results show that β-carotene interacted with other ingredients of emulsions changing their properties and behavior under gastrointestinal tract as well as the stability/bioaccessibility of β-carotene.

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

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

Supercritical CO2 Processing of a Functional Beverage Containing Apple Juice and Aqueous Extract of Pfaffia glomerata Roots: Fructooligosaccharides Chemical Stability after Non-Thermal and Thermal Treatments

The effects of supercritical CO₂ processing on the chemical stability of fructooligosaccharides (FOS) and other functional and nutritional compounds were evaluated employing non-thermal and thermal approaches. Apple juice was enriched with Pfaffia glomerata roots aqueous extract due to its high content of short-chain FOS and then subjected to different levels of temperature (40 and 60 °C), pressure (8 and 21 MPa), and CO₂ volume ratio (20 and 50%). The percentage of CO₂ volume was evaluated concerning the total volume of the high-pressure reactor. Also, the functional beverage was thermally treated at 105 °C for 10 min. Physicochemical properties (pH and soluble solid content), beta-ecdysone, sugars (glucose, fructose, and sucrose), and FOS (1-kestose, nystose, and fructofuranosylnystose) content were determined. The pH and soluble solid content did not modify after all treatments. The pressure and CO₂ volume ratio did not influence the FOS content and their chemical profile, however, the temperature increase from 40 to 60 °C increased the nystose and fructofuranosylnystose content. High-temperature thermal processing favored the hydrolysis of 1-kestose and reduced the sucrose content. Regarding beta-ecdysone, its content remained constant after all stabilization treatments demonstrating thus its high chemical stability. Our results demonstrated that supercritical CO₂ technology is a promising technique for the stabilization of FOS-rich beverages since the molecular structures of these fructans were preserved, thus maintaining their prebiotic functionality.

Extraction Methods for Obtaining Natural Blue Colorants

Background:

Blue is a color not often present in food. Even so, it is especially attractive to children. Today, most blue coloring agents used by the food industry are synthetic. With increasing health issues concern by the scientific community and the general population, there is a trend to look for natural alternatives to most synthetic products. There only exist few natural blue colorants, which are presented in a literature survey, along with the methods currently used for their recovery from natural sources. The best extraction methods and process parameters for the extraction of blue anthocyanins, iridoids and phycocyanin are discussed.

Methods:

A literature survey was conducted to detect the main sources of blue colorants found in nature. The focus was on the extraction methods used to recover such molecules, with the objective of finding efficient and environmentally safe techniques for application at industrial level, and, thus, allowing the production of natural blue colorants at scale high enough for food industry consumption.

Results:

The main natural blue colorants found in literature are anthocyanins, phycocyanin, and genipin. While anthocyanins can be recovered from a variety of plants, the source of phycocyanin are algae, and genipin can be obtained specifically from Gardenia jasminoides Ellis and Genipa americana L. Several extraction techniques have been applied to recover blue colorants from such sources, from classical methods using organic solvents, to more sophisticated technologies as ultrasoundassisted extraction, supercritical fluid extraction, pressurized liquid extraction, high-pressure extraction, and enzyme-assisted extraction.

Conclusion:

There is great potential for anthocyanins, phycocyanin and genipin use as natural food additives with health benefits, besides imparting color. However, the technologies for the colorants recovery and application are not mature enough. Therefore, this area is still developing, and it is necessary to evaluate the economic feasibility of the proposed extraction processes, along with the safety and acceptance of colored food using these additives.

Extraction of bioactive compounds from defatted passion fruit bagasse (Passiflora edulis sp.) applying pressurized liquids assisted by ultrasound

Passion fruit bagasse is a rich source of phenolic compounds, including piceatannol, a stilbene to which several biological activities are conferred. This work reports the application of pressurized liquid extraction (PLE) assisted by ultrasound (US) to intensify the extraction of phenolic compounds from defatted passion fruit bagasse (DPFB). PLE at different temperatures (65-75 °C) without and with different US powers (240-640 W) was performed to investigate the mechanism of the assisted process. The extracts were evaluated in terms of global, total phenolic (TP), piceatannol and total reducing sugar yields. The antioxidant capacity of the extracts was determined by FRAP and ORAC assays. PLE assisted by US increased the yields, resulting in 60% more TP and piceatannol. The observed yields suggest that the main mechanism driving PLE assisted by US from DPFB was the rise in temperature caused by the ultrasonic waves. Pearson coefficient revealed a strong correlation between antioxidant capacity and total phenolics and piceatannol yield. The three-line spline model was adequately fitted to the experimental curves, showing three extraction periods in which the recovery of TP and piceatannol was higher than 70% at the end of the falling extraction rate period. PLE assisted or not by US showed to be clean, efficient and green alternatives for the recovery of phenolic compounds. The findings of this work indicate that PLE assisted by US has a great potential to improve the extraction of bioactive compounds from natural products.

High-intensity ultrasound energy density: How different modes of application influence the quality parameters of a dairy beverage

This study evaluated the influence of the high-intensity ultrasound (HIUS) technology on the quality parameters of a model dairy beverage (chocolate whey beverage), operating under the same energy density (5000 J/mL), but applied at different ways. Two processes were performed varying nominal power and processing time: HIUS-A (160 W and 937 s), and HIUS-B (720 W and 208 s). Our objective was to understand how different modes of application of the same HIUS energy density could influence the microstructure, droplet size distribution, zeta potential, phase separation kinetic, color parameters and mineral profile of the chocolate whey beverage. The results demonstrated that the different modes of application of the same HIUS energy density directly influenced the final quality of the product, resulting in whey beverages with distinct physical and microstructural characteristics. The HIUS-B processing was characterized as a thermal processing, since the final processing temperature reached 71 °C, while the HIUS-A processing was a non-thermal process, reaching a final temperature of 34 °C. Moreover, HIUS-B process greatly reduced the droplet size and increased the lightness value in relation to the HIUS-A processing. Both treatments resulted in whey beverages with similar phase separation kinetics and were more stable than the untreated sample. The HIUS processes did not modify the mineral content profile. Overall, the study emphasizes the versatility of the HIUS technology, highlighting that the processing must not be based only on the applied energy density, since different powers and processing times produce dairy beverages with distinct characteristics.

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 1200 W 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 600 W increased the concentration of both organic acids, however, the intensification up to 1200 W 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.

Biorefinery of turmeric (Curcuma longa L.) using non-thermal and clean emerging technologies: an update on the curcumin recovery step

In this study, a biorefinery for the processing of turmeric (Curcuma longa L.) based on clean and emerging technologies has been proposed. High-intensity ultrasound (HIUS) technology was evaluated as a promising technique for curcumin recovery aiming to improve its extraction yield and technological properties as a colorant. In addition, we evaluated the effects of process conditions on the turmeric biomass after the extractions. The process variables were the number of stages of extraction with ethanol (1, 3 and 5) and the solvent to feed ratio (S/F) of 3, 5, 7, 9 (w/w). The highest curcumin content (41.6 g/100 g extract) was obtained using 1 wash and a S/F of 5 w/w, while the highest curcumin yield (3.9 g/100 g unflavored turmeric) was obtained using 5 stages and a S/F of 7. The extracts obtained by solid–liquid extraction assisted by HIUS showed a yellow color (157 and 169 of yellowness index) more intense than those obtained by the pressurized liquid extraction technique (101 of yellowness index) and better yield results than low-pressure solid–liquid extraction (using the same processing time). Thus, it was possible to obtain a characteristic yellow colorant with high curcumin yield in a short process time (5 min of extraction) using HIUS technology. Besides that, SEM images and FTIR spectra demonstrated that the turmeric biomasses processed by HIUS technology were not degraded.

In this study, a biorefinery for the processing of turmeric (Curcuma longa L.) based on clean and emerging technologies has been proposed.

Effect of high-intensity ultrasound on the nutritional profile and volatile compounds of a prebiotic soursop whey beverage

This study evaluated the nutritional profile and volatile compounds present in a novel prebiotic (inulin) soursop whey beverage, due to the effects of high-intensity ultrasound (HIUS). The prebiotic soursop whey beverage was produced and processed by non-thermal high-intensity ultrasound varying the power (0, 200, 400 and 600 W) and by high-temperature short time (72 °C for 15 s) thermal treatment. Total acidity, pH, ascorbic acid content, total phenolics compounds content, antioxidant activity, hypertensive activity, fatty acid profile, volatile organic compounds, macro and micro minerals, as well as the heavy metals in these products, were analyzed. Overall, the HIUS technology induced some positive changes in the nutritional profile of the soursop whey beverage including beneficial effects, e.g., increase of phenolic content, improvement of the antioxidant and anti-hypertensive activity and reduction of undesired minerals. Although some negative changes, such as degradation of the ascorbic acid, decrease of some minerals and production of certain volatile compounds were found, the beneficial effects were prominent, thus, opening new opportunities to develop healthy functional beverages.

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.

Construction and Validation of an Online Subcritical Adsorption-based Device for Assisting CO2 Recycling during a Supercritical Fluid Extraction Process

Background:

An efficient process for extracting food ingredients from plant materials should demand the use of a reduced volume of extraction solvent to obtain a final product that is free of solvent and reduces both the processing time and the costs. In some cases, achieving a new efficient process requires the modification, reconfiguration or renewal of elements that are part of a processing unit.

Objective:

The goal of this work is to describe the development of a modification of a commercial supercritical fluid extraction pilot unit designed to assist CO2recycling based on subcritical adsorption on an adsorbent material. In addition to the construction and validation of the system, a cost survey was performed to estimate the cost of the homemade device developed to allow effective CO2recycling.

Methods:

The developed device was tested using cotton and Celite®as model adsorption materials and annatto seeds (Bixa orellana L.) as a model plant material. A 0.65 L adsorption column was installed with a set of connections and valves that complemented the unit’s recycle system. The validation procedure consisted of defatting annatto seeds.

Results:

The proposed online subcritical adsorption-based device was technically validated using cotton as an adsorbent material. The cost survey showed that an estimated total cost of USD 5731.36 would be required to install the developed device in a Supercritical Fluid Extraction (SFE) unit similar to the one coupled here (5 L).

Conclusion:

The proposed device was demonstrated to be very promising for application in the pseudocontinuous SFE, recirculating the same amount of CO2mass exceeding the S/F values by 14 times, when compared to a process without a CO2recycling system.

Coupling of high-intensity ultrasound and mechanical stirring for producing food emulsions at low-energy densities

In this study, coupling of ultrasound (US) device and rotor-stator (RS), operating at low-energy densities, was studied as an alternative process to individual US and RS to produce modified starch-stabilized oil-in-water emulsions, as well as its potential use to encapsulate eugenol. To this aim, a full factorial design was employed to evaluate the effects of the US nominal power (0, 360 and 720 W) and RS nominal power (0, 150 and 300 W) on the physical properties, encapsulation efficiency and kinetic stability of emulsions produced. Firstly, the action of modified starch and eugenol onto interface oil-water was evaluated. The emulsifier was rapidly adsorbed on the interface water-sunflower oil reducing the interfacial tension from 25 to 16 mN/m, while eugenol did not show surface activity. The increase of energy density, in general, resulted in droplet size reduction, indicating the relevant role of the forces involved in the droplet breakup on emulsion stability. Coupling was more efficient on the droplets breakup producing smaller droplet size with narrower size distribution. While the coupled system work during 5 min for an energy density of 583 J/mL, the corresponding emulsification time for operating singly US and RS were 7.09 min and 17.04 min, respectively. Therefore, the main advantage associate to coupled process is the reduction of processing time to produce an emulsion with better kinetic stability.

Impact of Grinding Procedure on the Yield and Quality of the Extract from Clove Buds Using Supercritical Fluid Extraction

Introduction:

The effects of the grinding procedure on the supercritical fluid extraction (SFE) yields of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove are discussed in detail in this paper.

Methods:

For this purpose, five grinding procedures were employed: 1) continuous 1-min grinding, 2) continuous 2-min grinding, 3) two 1-min grinding periods with 6-min stop in between 4) continuous 4-min grinding, and 5) four 1-min grinding periods with 6-min stops in between. After that, the extractor was filled with 12 g of milled clove obtained using one of the grinding procedures while the other SFE parameters were kept constant (pressure of 150 bar, temperature of 40 °C, supercritical CO2 flow rate of 1.03×10−4 kg/s, static time of 20 min, and dynamic extraction time of 15 min). Then, the composition of the extract was evaluated by gas chromatography (GC).

Conclusion:

It was found that the grinding procedure has considerable effects on the recoveries of eugenol, β-caryophyllene, α-humulene, and eugenyl acetate from clove, and employing four 1-min grinding periods with 6-min stops in between as the grinding procedure gave the highest content of the aforementioned components in the extract.

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.

Extraction of bioactive compounds from genipap (Genipa americana L.) by pressurized ethanol: Iridoids, phenolic content and antioxidant activity

The search for compounds with functional properties from natural sources has grown in recent years as people have developed healthier habits. Therefore, the aim of this study was to evaluate the extraction of bioactive compounds from various parts of unripe genipap fruit (Genipa americana L.) by using pressurized ethanol to verify which part of the fruit provides the greatest recovery of the iridoids genipin and geniposide. Two process variables were studied: temperature (50 and 80°C) and pressure (2, 12 and 20 bar). The whole fruit and the peel, mesocarp, endocarp, endocarp+seeds and seeds of the fruit were studied. The endocarp presented with the highest recovery of genipin (48.6±0.6mg/g raw material) and the extraction from the mesocarp allowed a greater recovery of geniposide (59±1mg/g raw material). The highest values of total phenolic content were obtained with mesocarp extracts. The endocarp and mesocarp extracts presented the highest antioxidant activity as measured by FRAP and DPPH. These results are promising and support the use of unripe genipap fruit as a source of iridoids and natural antioxidants.

Whey-grape juice drink processed by supercritical carbon dioxide technology: Physicochemical characteristics, bioactive compounds and volatile profile

The effect of supercritical carbon dioxide technology (SCCD, 14, 16, and 18MPa at 35±2°C for 10min) on whey-grape juice drink characteristics was investigated. Physicochemical characterization (pH, titratable acidity, total soluble solids), bioactive compounds (phenolic compounds, anthocyanin, DPPH and ACE activity) and the volatile compounds were performed. Absence of differences were found among treatments for pH, titratable acidity, soluble solids, total anthocyanin and DPPH activity (p-value>0.05). A direct relationship between SCCD pressure and ACE inhibitory activity was observed, with 34.63, 38.75, and 44.31% (14, 16, and 18MPa, respectively). Regards the volatile compounds, it was noted few differences except by the presence of ketones. The findings confirm the SCCD processing as a potential promising technology to the conventional thermal treatment.