Effects of sonication on the kinetics of orange juice quality parameters

Stimulation of biosurfactant production by Lactobacillus plantarum using ultrasound

Due to their nonpathogenic status, biosurfactants produced by Lactobacillus strains have been shown to have potential applicability in several industrial sectors, particularly food and pharmaceutical industries. However, products with high efficiency are needed to fulfill the demand for these biosurfactants. Therefore, the present study investigated kinetic parameters, biomass and biosurfactant production of Lactobacillus plantarum ATCC 8014 applying standard MRS and modified MRS (supplemented standard MRS by nitrogen and carbon sources) culture medium under various ultrasonic frequencies of 20, 25, 35, 45, 130 and 950 kHz to obtain more efficient conditions. The optimum conditions were found when using the modified MRS treated by the frequency of 25 kHz (the power of 7.4 W) for 30 min, which led to a significant effect on the growth rate (µ_max, h^-1) rather than control. Furthermore, this condition caused the highest population (10.07 ± 0.1 log CFU/mL) and biomass concentration (4.33 ± 0.06 g/L), and lowest surface tension (39.26 ± 0.5 mN/m), leading to higher biosurfactant production. Hence, given the results of the present study, it can be established that controlled ultrasound exposure and supplementation of culture media using the main growth factors can intensify the microbial activity and the productivity of biological processes.

Preparative scale extraction of mangiferin and lupeol from mango (Mangifera indica L.) leaves and bark by different extraction methods

High biological value compounds are very important in the food and pharmaceutical sectors. The leading research interests are seeking efficient methods for extracting these substances. The objective of this study was to evaluate different extraction methods to obtain mangiferin and lupeol at preparative scale from leaves and bark of mango tree varieties Ataulfo and Autochthonous from Nayarit, Mexico. Four extraction techniques were evaluated such as maceration, Soxhlet, sonication (UAE) and microwave (MAE). Sonication gave the highest concentration of mangiferin and lupeol, demonstrating that extraction assisted by ultrasound could be an effective alternative to conventional extraction techniques because it is a low cost, simple and reliable process. Finally, mangiferin and lupeol were obtained at preparative scale with a higher concentration of bioactive compounds, 1.45 g 100 g^-1 y 0.92 mg 100 g^-1 sample on (d.b.), respectively. The barks from Ataulfo and Autochthonous mango trees turned out to be favourable sources for obtaining mangiferin and lupeol.

Emergence and era of ultrasonic's in fruit juice preservation: A review

Ultrasonic's has emerged to an unconditional extent in the last decade. It has found its application in fruit juice and beverage industry due to its multifunctional desired effects. The technology is inexpensive, simple, reliable, and environmentally friendly and highly effective in the preservation of juices with enhanced quality attributes. This review will enlighten your knowledge in understanding the basic concept of ultrasonic's with the principle, mechanism, and application in the food sector. It specifically reviews the explored effect of ultrasonication on different juices. It explores the influence of technology in enzyme inactivation, microbial inactivation and different quality attributes of fruit juices. It gives you an in-depth insight into the technology.

Ultrasound-Assisted Marination: Role of Frequencies and Treatment Time on the Quality of Sodium-Reduced Poultry Meat

The objective of this study was to evaluate the influence of high-power ultrasound (US) to accelerate marination of chicken breast; the effect of ultrasonic frequencies and marination times were investigated on samples containing full sodium levels (FS) or 25% sodium reduction, either by reducing NaCl (R50) or by its partial substitution with KCl (SR). Chicken breasts were marinated in plastic bags immersed in an ultrasonic bath operating with a frequency of 25, 45 or 130 kHz for 1, 3 or 6 h at a temperature of 2.5 ± 0.5 °C. Chicken marinated using US had a significantly higher uptake (p < 0.05) of sodium compared to control samples (no US) marinated for the same amount of time. No significant changes were observed in the quality parameters of sonicated chicken samples compared to controls. However, significant decreases (p < 0.05) in lipid oxidation were observed in SR samples when treated by US. These results suggest the use of ultrasound in the meat processing industry as a novel technology for enhancing marination processes and formulation of reduced sodium meat products.

Effect of Extraction Method and Thermosonication on Apple Juice Quality

This paper presents the results of a study on the influence of juice extraction and thermosonication methods on the content of microorganisms in juices stored under refrigeration and in ambient temperature. It was determined that the type of extraction device used influenced the content of microorganisms in juice. The lowest total content of mesophilic microorganisms was obtained in juice extracted on a piston press, and the highest was obtained using a centrifuge. The additional purpose was to evaluate the influence of ultrasonic treatment on selected parameters of apple juice quality: cloud value, antioxidant activity, total phenolic content, flavonoid content, and anthocyanin content. The ultrasound treatment of juice from the piston press was conducted at two levels of radiated sonic power so as to obtain sublethal and lethal temperatures of the juice. It was demonstrated that only ultrasound treatment within the range of lethal temperatures was sufficient to deactivate microorganisms. It was determined that thermosonication did not influence the deterioration of chemical properties of juices, with the exception of decreased anthocyanin content. The described method enables prolongation of the shelf life of fresh apple juice under refrigeration to 168 hours (7 days).

Effects of Ultrasound Processing on Physicochemical Parameters, Antioxidants, and Color Quality of Bayberry Juice

Effects of ultrasound on physicochemical parameters, ascorbic acid, anthocyanins, polymeric color (PC), 5-hydroxymethylfurfural (HMF), browning degree (BD), color, and superoxide dismutase (SOD) activity of bayberry juice were investigated. Treatments were carried out at amplitude levels from 20 to 100% of total input power (600 W) at 20 kHz for 2–10 min. The results showed that no notable differences in pH, total soluble solids, titratable acidity, and yellowness b∗ values were found in ultrasound-treated samples. The HMF, PC, BD, and L∗ values of bayberry juice obviously increased with enhancing ultrasonic intensity and treatment time. The ascorbic acid exhibited no notable changes after ultrasound treatment at lower intensity levels for short time, while anthocyanins showed an increasing tendency. With increasing ultrasonic intensity and time, antioxidants gradually decreased. Furthermore, the SOD activity apparently increased at short-time treatment and then decreased with ultrasound processing extension.

Thermo-Ultrasound-Based Sterilization Approach for the Quality Improvement of Wheat Plantlets Juice

The impact of thermo–ultrasound (TU) on the quality of fresh wheat plantlets juice is described in this study. Fresh wheat plantlets juice was treated with TU using ultrasound (US) bath cleaner with different treatment variables, including power (70%, 420 W), frequency (40 kHz), processing time (20 and 40 min) and temperature (30, 45 and 60 °C) for the determination of free amino acids, minerals, microbial loads and bioactive compounds. The treatments have non-significant effects in ºBrix, pH, and titratable acidity while a significant increase in non-enzymatic browning, viscosity, and cloud value. The TU treatment at 30 °C for 20 and 40 min has achieved the highest value of total phenolics, flavonoids, total antioxidant capacity, 2, 2-diphenyl-1-picrylhydrazyl (DPPH), carotenoids, anthocyanin contents, chlorophyll (a + b), minerals and free amino acids than other treatments as well as untreated sample. A lightly visible variation in the color was observed among all treatments. TU treatments also showed a significant impact on the reduction of microbial loads at 60 °C for 40 min. The verdicts revealed that TU at low temperature a viable option to improve the quality of wheat plantlets juice at an industrial scale as compared to alone.

Impact of ohmicsonication treatment on pectinmethylesterase in not-from-concentrate orange juice

The present study investigates the application of ohmicsonication (OS) as a new hurdle technology for pasteurization of Not-from-concentrate orange juice (NFCOJ). OS process parameters to inactivate pectinmethylesterase (PME) activity in NFCOJ were optimized using response surface methodology. The influence of Sonication (S), Thermosonication (TS), Ohmic heating (OH) and OS on inactivation of PME were compared to conventional heat (CH) treatment. Their effects on physical, chemical and microbiological contents were included. In comparison to fresh orange juice, the inactivation of PME was 96%, 95%, 89%, 90% and 29% for OS, OH, TS, CH and S treatments, respectively. Highest cloud value was obtained for OS (1.240 A) treatment. OS treatment gave a lower vitamin C loss compared to TS, OH and CH treatments. A significant increase in the total phenolic content were obtained in the following order OS > TS > OH > CH. OS treated juice also contained the lowest value of hydroxymethyl furfural (0.90 mg/L) compared to OH (0.95 mg/L), TS (1.37 mg/L) and CH (2.72 mg/L) treated samples. Overall, the results indicated that OS can be integrated as a substitute to pasteurization of NFCOJ.

The effect of ultrasound and freezing/thawing treatment on the physical properties of blueberries

The aim of the study was to investigate the effect of ultrasound treatment and freezing/thawing on the physical properties of blueberries (Vaccinium corymbosum L.). Fruits were subjected to ultrasound treatment, mechanical freezing/thawing, and freezing/thawing with subsequent ultrasound treatment. Moisture, density, porosity, hardness, springiness, cohesiveness, chewiness, gumminess, and color of blueberries were analyzed. Ultrasound treatment and freezing/thawing significantly decreased particle density and increased porosity of blueberries (p < 0.05). Ultrasound treatment and freezing/thawing produced significantly softer, less chewy and gummy berries in relation to control sample (p < 0.05). All techniques induced considerable changes in the color of blueberries. The results indicates that ultrasound treatment performed after freezing/thawing, didn't exert any effect on the fruits in relation to freezing/thawing alone (p > 0.05); however, it is an interesting technique for processing fresh blueberries and an alternative to freezing/thawing, when the preservation of product quality is a priority or when rapid textural damage is required before diffusion processes.

Improving the qualitative indicators of apple juice by Chitosan and ultrasound

Today's consumers desire for tasty, nutritious, and safe food products, so researchers are looking for new ways in which little heat or no heat at all is used for processing. This study was to evaluate the effect of treatment using an ultrasonic bath (for 15, 30, and 60 min at 40 and 60°C) and ultrasonic probe (for 10, 15, and 20 min at 40 and 60°C), treatment with Chitosan, and combination of them on the quality of apple juice that includes physicochemical features (pH, acidity, total solid matter), total polyphenol, total antioxidant capacity, the cloud point, and color values of Hunter (L*, a*, b*) in the treated samples and comparing them with each other. The results showed that ultrasound has no effect on the pH and acidity, while the total solid of ultrasound treatment was higher than controls in combination with Chitosan (p < 0.05). Total polyphenols of apple juice samples treated by ultrasonic probe are higher than an ultrasonic bath (p < 0.05). The total antioxidant capacity has improved in treatments (p < 0.05). According to the results there is a significant difference between the cloud point of control samples and Chitosan (p < 0.05). The L* (brightness) increased in ultrasonic probe method and had a significant decline in Chitosantreatment (p < 0.05). Findings from this study suggest that the use of ultrasound treatment in the production of apple juice can improve quality factors, and in this regard, ultrasonic probe is more effective.

Effects of high intensity ultrasound on the inactivation profiles of Escherichia coli K12 and Listeria innocua with salt and salt replacers

This study investigated the efficacy of power ultrasound (US) for the inactivation of Escherichia coli and Listeria innocua in the presence of sodium salt and salt replacers. Inoculated bacteria suspensions were treated at ultrasonic frequencies of 33 or 20 kHz alone or in combination, and in the presence of 5% NaCl, 5% KCl or 5% NaCl/KCl. Inactivation curves were fitted to the Weibull and the Biphasic models. The goodness of the fit for each model was evaluated based on R² and RMSE, while AIC and BIC values were used to choose the best model predictor. The Weibull and the biphasic models showed high regression coefficient (R² > 0.99) and low RMSE (<0.03) values. According to the results, inactivation up to 6 log for E. coli K12 and to 4 log for L. innocua could be achieved within one hour of ultrasound treatment. However, the presence of NaCl, or its substitution with KCl did not affect the degree of inhibition for both microorganisms. The results of this study suggest that power ultrasound treatment may be employed for the inactivation of microorganisms when low salt or salt substitutes are employed.

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.

Antioxidant degradation kinetics in apples

The effect of shelf storage under ambient conditions of cut apple dices on degradation of bioactive compounds such ascorbic acid, total phenols, antioxidant activity (% DPPH inhibition) and PPO activity were investigated. The results indicated that antioxidant activity declined significantly over 80 min storage of diced apples at ambient temperature. Similar trend was observed for ascorbic acid, total phenols and PPO activity. Ascorbic acid, total phenols and antioxidant activity degradation followed first-order kinetics where the rate constant (k) was found to be in range for all the thirteen cultivars, though initial ascorbic acid and phenol content varied in different apple cultivars. The reaction rate constant (k) for first order degradation ranged from 1.16 to 1.97, 0.89 to 1.29 and 0.37 to 1.54 for antioxidant activity, total phenols and ascorbic acid, respectively. This explains that antioxidant activity degrades at higher rate than total phenols and ascorbic acid, which also corroborates that antioxidant activity is affected by both total phenols and ascorbic acid content. In general, total antioxidant activity for apple dices kept for 80 min under ambient conditions exhibited lower values as compared to control.

Integrated phenotypic-genotypic approach to understand the influence of ultrasound on metabolic response of Lactobacillus sakei

The lethal effects of soundwaves on a range of microorganisms have been known for almost a century whereas, the use of ultrasound to promote or control their activity is much more recent. Moreover, the fundamental molecular mechanism influencing the behaviour of microorganisms subjected to ultrasonic waves is not well established. In this study, we investigated the influence of ultrasonic frequencies of 20, 45, 130 and 950 kHz on growth kinetics of Lactobacillus sakei. A significant increase in the growth rate of L. sakei was observed following ultrasound treatment at 20 kHz despite the treatment yielding a significant reduction of ca. 3 log cfu/mL in cells count. Scanning electron microscopy showed that ultrasound caused significant changes on the cell surface of L. sakei culture with the formation of pores "sonoporation". Phenotypic microarrays showed that all ultrasound treated L. sakei after exposure to various carbon, nitrogen, phosphorus and sulphur sources had significant variations in nutrient utilisation. Integration of this phenotypic data with the genome of L. sakei revealed that various metabolic pathways were being influenced by the ultrasound treatments. Results presented in this study showed that the physiological response of L. sakei in response to US is frequency dependent and that it can influence metabolic pathways. Hence, ultrasound treatments can be employed to modulate microbial activity for specialised applications.

Ultrasound assisted synthesis of stable oil in milk emulsion: Study of operating parameters and scale-up aspects

In the present work, application of ultrasound and stirring individually or in combination for improved emulsification of turmeric oil in skimmed milk has been investigated. The effect of different operating parameters/strategies such as addition of surfactant, sodium dodecyl sulfate (SDS), at different concentrations, quantity of oil phase, applied power, sonication time and duty cycle on the droplet size have been investigated. The stability of emulsion was analyzed in terms of the fraction of the emulsion that remains stable for a period of 28days. Optimized set of major emulsification process variables has been used at higher emulsion volumes. The effectiveness of treatment approach was analyzed based on oil droplet size, energy density and the time required for the formation of stable emulsion. It was observed that the stable emulsion at 50mL capacity with mean droplet diameter of about 235.4nm was obtained with the surfactant concentration of 5mg/mL, 11% of rated power (power density: 0.31W/mL) and irradiation time of 5min. The emulsion stability was higher in the case of ultrasound assisted approach as compared to the stirring. For the preparation of stable emulsion at 300mL capacity, it was observed that the sequential approach, i.e., stirring followed by ultrasound, gave lower mean droplet diameter (232.6nm) than the simultaneous approach, i.e., ultrasound and stirring together (257.9nm). However, the study also revealed that the simultaneous approach required very less time (15min) to synthesize stable emulsion as compared to the sequential approach (30min stirring and 60min ultrasound). It was successfully demonstrated that the ultrasound-assisted emulsification in the presence of SDS could be used for the preparation of stable turmeric oil-dairy emulsions, also providing insights into the role of SDS in increasing the stability of emulsions and of ultrasound in giving lower droplet sizes.

Effect of sonication on bioaccessibility and cellular uptake of carotenoids from preparations of photoautotrophic Phaeodactylum tricornutum

With regard to its cost-effective cultivation and the composition of high-value nutrients, the diatom Phaeodactylum tricornutum (P. tricornutum) attracts interest for the use in human nutrition. Besides a number of important nutrients, it is rich in carotenoids. Therefore, this study aimed to investigate the potential of P. tricornutum as a carotenoid source for human nutrition. In photoautotrophically produced P. tricornutum biomass the carotenoid constitution, bioaccessibility (in vitro digestion model) and cellular uptake in differentiated Caco-2 cells (Transwell model system) was determined. Furthermore, the influence of sonication on these parameters was investigated. The results indicate that β-carotene, zeaxanthin and fucoxanthin were the main carotenoids found in P. tricornutum. Moreover, these carotenoids showed a good bioaccessibility (β-carotene: 25%, zeaxanthin: 27%, fucoxanthin: 57%), which is further improved by sonication for β-carotene and fucoxanthin. In line with the good bioaccessibility, fucoxanthin was the most abundant carotenoid in Caco-2 cells followed by zeaxanthin. In contrast, β-carotene could not be detected in the cells. The present study demonstrated that P. tricornutum represents a good source of carotenoids, particularly fucoxanthin. Thus, this diatom can contribute to the intake of bioaccessible carotenoids, even without processing. In addition, sonication might be a useful tool to improve the carotenoid bioaccessibility.

Combined Effect of Ultrasound and Mild Temperatures on the Inactivation of E. coli in Fresh Carrot Juice and Changes on its Physicochemical Characteristics

The combination of ultrasound and mild temperatures to process fruits and vegetables juices is a novel approach that is showing promising results for microbial inactivation and preservation of bioactive compounds and sensory attributes. This study centers on investigating the inactivation of Escherichia coli (ATCC 11755) in carrot juice as a result of the combined effect of ultrasound (24 kHz frequency, 120 μm, and 400 W) with temperature (50, 54, and 58 °C) and processing time (0 to 10 min). In addition, the possible changes in physicochemical properties and the retention of bioactive compounds after processing were analyzed. Microbial inactivation with ultrasound treatment at 50 °C resulted in 3.5 log reduction after 10 min, whereas at 54 °C almost 5 log reduction was attained in the same period of time; meanwhile, for treatment at 58 °C, no viable cells were detected (>5 log reduction) after 2 min. There was no significant difference (P > 0.05) on pH (6.80 to 6.82), °Brix (8.0 to 8.5), titratable acidity (0.29% to 0.30%), total carotenoid (1774 to 1835 μg/100 mL), phenolic compounds (20.19 to 20.63 μg/mL), ascorbic acid (4.8 mg/100 mL), and color parameters between fresh and ultrasound treated samples at the studied temperatures. To predict the inactivation patterns, observed values were tested using 3 different general models: first-order, Weibull distribution, and biphasic. The Weibull and biphasic models show good correlation for inactivation under all processing conditions. Results show ultrasound in combination with mild temperature could be effectively used to process fresh carrot juice providing a safe product without affecting physicochemical characteristics.

PRACTICAL APPLICATIONS

The combination of ultrasound and mild temperatures is effective in reducing microbial load in carrot juice to safe levels. This combination would be beneficial in the industrial processing of carrot juice without altering the quality attributes or bioactive compounds.

Impact of corona discharge plasma treatment on microbial load and physicochemical and sensory characteristics of semi-dried squid (Todarodes pacificus)

The use of corona discharge plasma jet (CDPJ) for the improvement of the sanitary quality of semi-dried squid was investigated. Microbial contaminants, namely aerobic, coliforms, and molds and yeasts, were detected in the samples. The CDPJ generated using 20 kV DC voltage at 58 kHz frequency was used for the decontamination treatment (1-10 min). The bacterial contaminants and molds and yeasts were inactivated in the range of 1.5-2.1 and at 1.9 log CFU/g, respectively. The inactivation pattern was well fitted to the first-order kinetics model. The CDPJ treatment for 10 min did not exert significant changes (p > 0.05) in VBN and the trimethylamine content of semi-dried squid as compared to untreated controls. On the contrary, significant changes (p < 0.05) in moisture content, water activity, pH, color, and TBARS levels were observed upon plasma exposure. However, the CDPJ-treated samples displayed slightly better sensory properties than the controls in terms of appearance, visual color, and flavor.

Ascorbic acid stability in fruit juices during thermosonication

Thermosonication is an emerging technology useful for inactivating microorganisms and enzymes in fruit juices. However, the effect of the ultrasound processing on the ascorbic acid content is not clear and the results reported in the literature are contradictory. In this work, the impact of sonication and thermosonication on the ascorbic acid content was first evaluated in model systems. Degassed model solutions at four different pH values (3-6) were processed with or without sonication for 60min at two different conditions of temperature (25 and 55°C). In all cases, the ascorbic acid was stable under the treatment. After that, two commercial deaerated fruit juices were processed with and without US at 55°C. The ascorbic acid was also retained in these juices after the ultrasound processing under the most severe conditions studied. In conclusion, previous degassing/deaerating of fruit juices is recommended to prevent ascorbic acid degradation when thermosonication is applied.

Manothermosonication as a useful tool for lipid extraction from oleaginous microorganisms

Manothermonication is a recognized and efficient method used for sterilization in food preservation. The synergistic effect of sonication combined with pressure and temperature allows enhancing the cavitation activity. Never employed for extraction, this study is about the transposition of this process as a tool of extraction. In this study, Rhodosporidium toruloides yeast was submitted to extraction by four modes of sonication, with a temperature ranged from 20 to 55°C and a pressure between 1 to 2bars. The lipids extraction yields were compared to the conventional maceration. Microbial oils obtained from both processes were analyzed and quantified by HPTLC (High Performance Thin-Layer Chromatography) and GC-FID (Gas Chromatography with flame ionization detector) after transesterification of lipids. Manothermosonication (30min, 2bars, 55°C) permits to enhance of approximately 20% the extraction yield of lipids to compared to conventional maceration. The fatty acid profiles of each pretreatment and extraction by US, MS, TS and MTS do not affect the fatty acid profiles of yeast (majority of oleic acid (C18:1n9), linoleic acid (C18:2n6) and palmitic acid (C16:0)). Manothermosonication technique shows a great potential for lipid extraction from oleaginous microorganisms.

Effect of ultrasound on some chemical and microbiological properties of sour cherry juice by response surface methodology

In this study, it is aimed to determine effect of ultrasonication on some chemical and microbiological properties of sour cherry juice by response surface methodology, since ultrasound is known as an alternative method for thermal food processing. Sour cherry juice was sonicated at varying amplitude levels (50, 75, 100%); moderate temperatures (20, 30, 40 ℃); and treatment times of 2, 6, 10 min at a constant frequency of 20 kHz. Different ultrasonication amplitudes, temperatures, and times had no significant effect on pH,°Bx, and titratable acidity. A significant increase in total monomeric anthocyanins was observed as the amplitude level and temperature increased (p < 0.01). An increase in the total phenolics was also obtained as the temperature increased (p < 0.05). The effect of amplitude level on antioxidant capacity of sour cherry juice was also found significant (p < 0.05). Color parameters (L*, a*, b*, C, h) generally increased by increasing temperature, amplitude level, and treatment time. It was determined that Escherichia coli O157:H7 significantly affected by temperature and treatment time (p < 0.05).

Ultrasound assisted forward osmosis concentration of fruit juice and natural colorant

The present study deals with the effect of higher and lower molecular weight compounds present in the feed on concentration polarization during forward osmosis concentration and its mitigation by the application of ultrasound. The effects of ultrasound on transmembrane water flux at different forward osmosis membrane orientations and different model feed solutions consisting of sucrose and pectin have also been evaluated. The feed containing sucrose and pectin subjected towards active layer of the membrane was found to be the most suitable orientation. The application of ultrasound (30kHz) significantly reduced the concentration polarization when the feed contains sucrose concentration up to 5%. Whereas, in case of feed containing 0.5% pectin, the ultrasound was not found to be effective in dislodging the gel layer formation resulting in severe external concentration polarization on the membrane surface. In comparison to the ordinary forward osmosis process, the ultrasound-assisted forward osmosis process resulted in higher water fluxes in case of sweet lime juice as well as rose extract containing anthocyanin. The degradation of rose anthocyanin due to ultrasound was found to be 1.82%. Application of ultrasound was found to be an effective way in mitigating concentration polarization on the forward osmosis membrane resulting in increased flux.

Ultrasonic accelerates asparagine-glucose non-enzymatic browning reaction without acrylamide formation

Ultrasonic accelerated the asparagine-glucose non-enzymatic browning reaction with significant decrease of glucose and asparagine concentrations, and marked increase of intermediate products (UV-absorbance value at 294nm, Abs₂₉₄), melanoidins (UV-absorbance value at 420nm, Abs₄₂₀) and in vitro antioxidant activity (DPPH free radical scavenging activity). As the ultrasonic intensity was 17.83W/cm², the asparagine-glucose solution's Abs₂₉₄, Abs₄₂₀ and antioxidant activity increased from 0 to 1.26, 0.88 and 21.56%, respectively, and the glucose and asparagine concentrations of the asparagine-glucose solution reduced 58.97 and 12.57%, respectively. The high performance liquid chromatography (HPLC)-Diode Array Detector (DAD) analyses showed that no acrylamide was detected after 50-min ultrasonic reaction. This study suggested that ultrasonic at higher intensity was a potential method to accelerate the non-enzymatic browning reaction in the asparagine-glucose solution without acrylamide production.

Enzymatic inactivation and antioxidant properties of blackberry juice after thermoultrasound: Optimization using response surface methodology

The purpose of this research was to optimize the thermoultrasound conditions for blackberry juice using the response surface methodology and considering juice quality parameters and antioxidant capacity. With the exception of microbial growth, the response variables showed high correlation coefficients with the mathematical model (R²adj>0.91). Thermoultrasound treatment inactivated all the evaluated microorganisms, and at the optimum conditions (50±1°C at 17±1min) it increased enzyme inactivation and antioxidant activity in comparison to pasteurized juice. The results demonstrated that thermoultrasound can be an alternative to pasteurization for the production of safe and high-quality juices with the added value of higher concentration of bioactive compounds and antioxidant capacity.

Enhancing mung bean hydration using the ultrasound technology: description of mechanisms and impact on its germination and main components

The ultrasound technology was successfully used to improve the mass transfer processes on food. However, the study of this technology on the grain hydration and on its main components properties was still not appropriately described. This work studied the application of the ultrasound technology on the hydration process of mung beans (Vigna radiata). This grain showed sigmoidal hydration behavior with a specific water entrance pathway. The ultrasound reduced ~25% of the hydration process time. In addition, this technology caused acceleration of the seed germination – and some hypothesis for this enhancement were proposed. Moreover, it was demonstrated that the ultrasound did not change both structure and pasting properties of the bean starch. Finally, the flour rheological properties proved that the ultrasound increased its apparent viscosity, and as the starch was not modified, this alteration was attributed to the proteins. All these results are very desirable for industry since the ultrasound technology improves the hydration process without altering the starch properties, accelerates the germination process (that is important for the malting and sprouting process) and increases the flour apparent viscosity, which is desirable to produce bean-based products that need higher consistency.