Influence of postharvest ultrasounds treatments on tomato (Solanum lycopersicum,cv. Zinac) quality and microbial load during storage

Whole tomato fruits were treated at ultrasonic power levels from 10% to 100%, and at a constant frequency of 45 kHz, for different times (1–19 min). A central composite rotatable design (CCRD) was applied to optimise ultrasonic treatments for tomato quality (colour, texture and total phenolic content (TPC)) maintenance. According to response surface analysis, the optimal treatment parameters were 55%_10 min, 80%_15 min and 100%_19 min. At these conditions, and especially at higher power levels, a maximum retention of colour and texture, as well as an increase of TPC and microbial reduction were obtained in comparison with untreated fruits during 15 storage days at 10 °C. The ultrasounds treatment was found to be effective in delaying colour development and texture losses, preserving sensorial quality of whole tomato, with increase of TPC and microbial load reduction. Moreover, this postharvest treatment can be used as an alternative for extending fresh fruits shelf-life.     

High-intensity ultrasonication impact on the chlorothalonil fungicide and its reduction pathway in spinach juice

Among different novel technologies, sonochemistry is a sustainable emerging technology for food processing, preservation, and pesticide removal. The study aimed to probe the impact of high-intensity ultrasonication on chlorothalonil fungicide degradation, reduction pathway, and bioactive availability of spinach juice. The chlorothalonil fungicide-immersed spinach juice was treated with sonication at 360 W, 480 W, and 600 W, 40 kHz, for 30 and 40 min at 30 ± 1 °C. The highest reduction of chlorothalonil fungicide residues was observed at 40 min sonication at 600 W. HPLC-MS (high-performance liquid chromatography-mass spectroscopy) analysis revealed the degradation pathway of chlorothalonil and the formation of m-phthalonitrile, 3-cyno-2,4,5,6-tetrachlorobenamide, 4-dichloroisophthalonitrile, trichloroisophtalonitrile, 4-hydoxychlorothalonil, and 2,3,4,6-tetrachlorochlorobenzonitrile as degradation products. High-intensity sonication treatments also significantly increased the bioavailability of phenolic, chlorophyll, and anthocyanins and the antioxidant activity of spinach juice. Our results proposed that sonication technology has excellent potential in degrading pesticides through free radical reactions formation and pyrolysis. Considering future perspectives, ultrasonication could be employed industrially to reduce pesticide residues from agricultural products and enhance the quality of spinach juice.     

Effective control of antibiotic resistance using a sonication-based combinational treatment and its application to fresh food

Antibiotics have been widely used to treat several infectious diseases. However, the overuse of antibiotics has promoted the emergence and spread of antibiotic resistant bacteria (ARB) in various fields, including the food industry. In this study, the antimicrobial efficacies of two conventional sterilization methods, mild heat, and sonication, were evaluated and optimized to develop a new strategy against ARB. Simultaneous mild heat and sonication (HS) treatment led to a significant reduction in viable cell counts, achieving a 5.58-log reduction in 4 min. However, no remarkable decrease in viable cell counts was observed in individually treated groups. Interestingly, the release of antibiotic resistance genes (ARGs) increased in a time-dependent manner in the heat-treated and HS-treated groups. The inactivation levels of ARGs increased as the HS treatment time increased from 2 to 8 min, and most ARGs were degraded after 8 min. In contrast, no significant inactivation of ARGs was observed in the heat-treated and sonication-treated groups after 8 min. These results reveal the synergistic effect of the combination treatment in controlling not only ARB but also ARGs. Finally, on applying this newly developed combination treatment to fresh food (cherry tomato and carrot juice), 3.97- and 4.28-log microbial inactivation was achieved, respectively. In addition, combination treatment did not affect food quality during storage for 5 days. Moreover, HS treatment effectively inactivated ARGs in fresh food systems.     

Application of ultrasound in grape mash treatment in juice processing

Recently, application of ultrasound has attracted considerable interest as an alternative approach to traditional methods. In this study, response surface methodology (RSM) was used to optimize the conditions for grape mash treatment by ultrasound and by combination of ultrasound and enzyme. The results indicated that optimal conditions were the temperature of 74 °C and the time of 13 min for sonication treatment; and were the enzyme concentration of 0.05% and the time of 10 min for combined ultrasound and enzyme treatment. In comparison with traditionally enzymatic treatment, sonication treatment increased extraction yield 3.4% and shortened treatment time over three times; combined ultrasound and enzyme treatment increased extraction yield slightly, only 2%, but shortened treatment time over four times. After sonication treatment, enzymatic treatment increased extraction yield 7.3% and total treatment time of this method was still shorter than that of traditionally enzymatic treatment method. Besides, application of ultrasound improved the grape juice quality because it increased contents of sugars, total acids and phenolics as well as color density of grape juice.     

Sustainable emerging sonication processing: Impact on fungicide reduction and the overall quality characteristics of tomato juice

Sonication is an emerging sustainable and eco-friendly technology that has been broadly explored in food processing and preservation. Sonication has the edges of low energy consumption and high efficiency than conventional decontamination methods and would not pass on secondary pollutants. In the current research, we analyzed the impact of sonication on anilazine fungicide reduction, bioactive compound, antioxidant activity, colloidal stability, and enzymatic and microbial load of tomato juice. Sonicated treatments were carried out at 40 kHz, 480 W, 30 ± 2 °C for 0, 8, 16, 24, 32, and 40 min in an ultrasonic bath cleaner. The GC–MS outcomes revealed that the anilazine maximum reduction in tomato juice attained 80.52 % at 40 min of sonication. The anilazine concentration reduced significantly (p ≤ 0.05) with increased sonication time. In contrast, sonication treatments have acquired the highest TFC, TPC, ascorbic acid, carotenoids, lycopene, ABTS, and ORAC assay than the untreated sample. The Sonication process significantly improved (p ≤ 0.05) colloidal stability by reducing particle size distribution, apparent viscosity, and sedimentation index. Sonication prolonged tomato juice's shelf life by reducing the total viable count from 6.31 to 1.91 log CFU/mL. Polygalacturonase and pectin methyl esterase of the sonication sample at 40 min were inactivated by 44.32 % and 64.2 %, respectively. Considering this issue from a future perspective, sonication processing can be used industrially to enhance fruit juice's nutritional properties and shelf life and reduce pesticides and other organic residues.     

Impact of sonolytic ozonation (O3/US) on degradation of pesticide residues in fresh vegetables and fruits: Case study of Faisalabad,Pakistan

High pesticide residues in fresh produce is a serious food safety issue. This study was aimed at assessing the pesticides residues in some important vegetables and fruits marketed in Faisalabad, Pakistan and the impact of sonolytic ozonation (O₃/US) treatment in removing these contaminants. From a short grower’s survey, five registered and mostly used pesticides (acetamiprid, carbendazim, imidacloprid, thiacloprid and thiamethoxam) were identified. A time optimization trial of O₃/US application (05, 10 and 15 min) on okra, showed that 10 min treatment significantly reduced three identified chemicals (thiamethoxam 100 %, imidacloprid and thiacloprid 97.17 %), without any adverse effect on its quality. In follow up trial, five fresh vegetables (cauliflower, chillies, cucumber, spinach and tomato) three fresh fruits (grapes, guava and peach) collected from three markets of Faisalabad, were pooled together to have uniform samples. Vegetables and fruits were treated with O₃/US for 10 and 6 min, respectively, along with control (simple tap wash) for determining the impacts on pesticides degradation. Samples were processed for extraction, clean up and analysis using HPLC-UV–Vis in isocratic mode. The data revealed the presence of five mentioned chemicals, with an accumulative mean residue of 9.006 and 1.921 µg/g in tested vegetables and fruits, respectively. After subjecting to O₃/US, the accumulative chemical residues were reduced to 3.214 µg/g (64.313 %) and 1.064 (44.6 %) in treated vegetables and fruits respectively. Irrespective of fresh produce, the mean residues of thiamethoxam, imidachloprid, acetamiprid and thiachloprid and carbendazim were reduced by 99.3 %, 52.6 %, 65.2 %, 87.3 % and 72% respectively. It was concluded that sonolytic ozonation treatment was effective in significant reduction of pesticide residues from vegetables and fruits and thus can be employed as a good food safety practice at culinary level to reduce the associated health hazardous risks.     

Impact of microsecond-pulsed plasma-activated water on papaya seed germination and seedling growth

The seed of Carica papaya consists of a hard shell-like testa with inhibitors in vivo causing slow, erratic and asynchronous germination. In this work, plasma-activated water prepared by microsecond-pulsed plasma jets (μPAW) was applied to treat papaya seeds. The μPAW after plasma activation of 30 min was about 40 ℃. The reactive species such as NO₂, NO₃, and H₂O₂ in the μPAW activated from deionized water were measured and correlated to the seed germination rate and the seedling growth performance. The μPAW-treated papaya seed achieved a higher germination rate of 90%, which is 26% higher than the control group using deionized water. Comparing the results with a hot water (40 ℃) reference group showed that the reactive species in μPAW played primary roles in germination improvement, with little effect caused by the heat shock. The μPAW also sterilized the treated seeds, reducing the germination stress. The morphological change in the seeds was observed by SEM, showing an effect of physical etching after treatment promoting seed imbibition. The biochemical mechanism of the seed germination was deduced with reference to the evolution of surface chemistry, functional groups, and ABA content. The accelerated seed metabolism observed was corresponded to the chemical modification pathway. Besides, early seedlings developed from treated seeds were observed to be healthy, grow more leaves, and have better root structures. The content of MDA in the treated papaya seedlings decreased along with increased SOD and higher ion concentration. The μPAW that can be prepared at atmospheric pressure for bulk production offers a low-risk and cost-effective seed priming technology that may significantly increase the production of agricultural crops.     

Mechanism and optimization of non-thermal plasma-activated water for bacterial inactivation by underwater plasma jet and delivery of reactive species underwater by cylindrical DBD plasma

Plasma-activated water (PAW) has been in use for the past decade in sanitization against bacteria and other microorganisms. This research study compared PAW generated by a DC positive flyback transformer (FBT) underwater plasma jet with delivery of reactive species underwater by cylindrical dielectric barrier discharge (C-DBD) with a neon transformer. A Box–Behnken design was adopted as a response surface methodology (RSM) to design the experimental plan and optimize operating parameters including time, gas flow, and gas ratio. The physical responses comprise optical emission spectroscopy (OES), pH, oxidation-reduction potential (ORP), and electrical conductivity (EC). The chemical responses consist of hydrogen peroxide (H₂O₂) and hydroxyl radicals (OH·). The biological responses include Escherichia coli reduction and Staphylococcus aureus reduction. The optimal condition for underwater plasma jet was found to be Ar gas with a flow rate of 3 slm for 6.5 min of treatment time, which can reduce E. coli and S. aureus to 7.14 ± 0.14 and 3.10 ± 0.26 in log, respectively. Also, the optimal condition for delivery of reactive species underwater by C-DBD plasma was found to be Ar (99%): O₂ (1%) gas mixture with an Ar gas flow rate of 4 slm for a treatment time of 11.5 min, which could reduce E. coli and S. aureus to 0.45 ± 0.07 and 2.45 ± 0.23 in log, respectively.     

Impact of sonochemical synthesis condition on the structural and physical properties of MnFe2O4 spinel ferrite nanoparticles

Herein, we report sonochemical synthesis of MnFe₂O₄ spinel ferrite nanoparticles using UZ SONOPULS HD 2070 Ultrasonic homogenizer (frequency: 20 kHz and power: 70 W). The sonication time and percentage amplitude of ultrasonic power input cause appreciable changes in the structural, cation distribution and physical properties of MnFe₂O₄ nanoparticles. The average crystallite size of synthesized MnFe₂O₄ nanoparticles was increased with increase of sonication time and percentage amplitude of ultrasonic power input. The occupational formula by X-ray photoelectron spectroscopy for prepared spinel ferrite nanoparticles was (Mn_0.29Fe_0.42)[Mn_0.71Fe_1.58]O₄ and (Mn_0.28Fe_0.54) [Mn_0.72Fe_1.46]O₄ at sonication time 20 min and 80 min, respectively. The value of the saturation magnetization was increased from 1.9 emu/g to 52.5 emu/g with increase of sonication time 20 min to 80 min at constant 50% amplitude of ultrasonic power input, whereas, it was increased from 30.2 emu/g to 59.4 emu/g with increase of the percentage amplitude of ultrasonic power input at constant sonication time 60 min. The highest value of dielectric constant (ε′) was 499 at 1 kHz for nanoparticles at sonication time 20 min, whereas, ac conductivity was 368 × 10⁻⁹ S/cm at 1 kHz for spinel ferrite nanoparticles at sonication time 20 min. The demonstrated controllable physical characteristics over sonication time and percentage amplitude of ultrasonic power input are a key step to design spinel ferrite material of desired properties for specific application. The investigation of microwave operating frequency suggest that these prepared spinel ferrite nanoparticles are potential candidate for fabrication of devices at high frequency applications.     

High intensity ultrasound treatment of protein isolate extracted from dephenolized sunflower meal: Effect on physicochemical and functional properties

The influence of high intensity ultrasound (HIUS) on physicochemical and functional properties of sunflower protein isolates was investigated. Protein solutions (10% w/v) were treated with ultrasound probe (20 kHz) and ultrasound bath (40 kHz) for 5, 10, 20 and 30 min. Thermal stability of protein isolates was reduced as indicated by differential scanning calorimetry. Minimum thermal stability was observed at 20 min of sonication and increased further with increase in treatment time indicating aggregation at prolonged sonication. SDS-PAGE profile of proteins showed a significant reduction in molecular weight. Further, surface hydrophobicity and sulfhydryl content increased after HIUS treatment indicating partial unfolding of proteins and reduction in the intermolecular interactions. The particle size analysis showed that HIUS treatment reduced the particle size. Less turbid solution were observed largely due to reduction in particle size. HIUS decreased the available lysine content in protein isolates. Solubility, emulsifying capacity, emulsion stability, foaming capacity, foam stability and oil binding capacity were improved significantly, while as, water binding capacity was decreased. The effect of HIUS on physicochemical and functional properties of sunflower protein isolates was more pronounced in probe sonication rather than bath sonication. Protein isolates with improved functional properties can be obtained using high intensity ultrasound technology.     

Effect of thermoultrasound on aflatoxin M1 levels,physicochemical and microbiological properties of milk during storage

The aim of this research was to determine the physicochemical properties, microbial counts and aflatoxin M₁ (AFM₁) levels of thermoultrasonicated, pasteurized and untreated milk (control) at days 1, 7 and 14 of storage. Thermoultrasound treatment was performed at a rate of 20 kHz for 10 or 15 min and 95% amplitude on homogenized and non-homogenized milk samples. Results showed that most physicochemical parameters were within the Mexican norms established for milk. Ultrasound treatment for 15 min reduced solids precipitation (p < 0.05) in unhomogenized milk during storage as compared to the pasteurized milk. All samples complied with aerobic mesophilic counts limits set by the Mexican norm except the control and the homogenized milk sample which was thermoultrasonicated for 10 min. Enterobacteriaceae counts of pasteurized and 15 min-thermoultrasound homogenized milks complied with the norm. The lowest levels of AFM₁ were found in the 10 min-thermoultrasound unhomogenized milk (0.15 ± 0.05 pg AFM⁠₁E/mL) one day after storage. Thermoultrasound did not affect the color of samples but homogenized milk treated for 10 min exhibited less total color difference. A high phenolic content was found in thermoultrasound and pasteurized milks on day 1. Thermoultrasound could be an alternative to milk pasteurization that preserves the physicochemical and microbiological quality of milk while reducing AFM₁ levels.     

High-power ultrasound in olive paste pretreatment. Effect on process yield and virgin olive oil characteristics

The effect of high-power ultrasound on olive paste, on laboratory thermo-mixing operations for virgin olive oil extraction, has been studied. Direct sonication by an ultrasound probe horn (105 W cm⁻² and 24 kHz) and indirect sonication with an ultrasound-cleaning bath (150 W and 25 kHz) were applied and their effects compared with the conventional thermal treatment.

A quick-heating of olive paste, from ambient (12–20 °C) to optimal temperature conditions (28–30 °C), and an oil extractability improvement were observed when applying sonication. Better extractability was obtained by direct sonication for high moisture olives (>50%) whereas indirect sonication gave greater extractability for low moisture olive fruits (<50%).

Optimal application of ultrasound was achieved with direct sonication for 4 min at the beginning of paste malaxation and with indirect sonication during the malaxation time.

Effect of high-power ultrasound on oil quality parameters and nutritional and sensory characteristics were studied. Changes in quality parameters (free acidity value, peroxide value, K270 and K232) were not found, however significant effects on the levels of bitterness, polyphenols, tocopherols (vitamin E), chlorophyll and carotenoids were observed. Oils from sonicated pastes showed lower bitterness and higher content of tocopherols, chlorophylls and carotenoids. Related to sensory characteristics, off-flavour volatiles were not detected in oils from sonication treatments. Total peak areas of volatiles and the ratio hexanal/E-2-hexenal, as determined by SPME analysis, were lower than non-sonicated reference oils; sensory evaluation by panel test showed higher intensity of positive attributes and lesser of negative characteristics than those untreated.     

Sonozonation: Enhancing the antimicrobial efficiency of aqueous ozone washing techniques on cherry tomato

Ultrasound requires high power and longer treatment times to inactivate microorganisms when compared to ultrasound combined with other technologies. Also, the antimicrobial efficiency of aqueous ozone increases with an increase in its concentration and exposure time, but with a detrimental effect on the quality of the treated food. In this study, the effect of aqueous ozone at low concentration, multi-mode frequency irradiation and their combination on microbial safety and nutritional quality of cherry tomato was investigated. Individual washing with aqueous ozone and mono-mode frequency irradiation resulted in <1 log CFU/g reduction in the spoilage microorganisms, while dual-mode frequency irradiation (DMFI) resulted in higher microbial reduction (1.3–2.6 1 log CFU/g). The combined system (20/40 kHz + aqueous ozone) on the other hand, resulted in >3 log CFU/g microbial reduction. The application of DMFI enhanced the antimicrobial efficiency of aqueous ozone without any detrimental effect on the physicochemical properties (except the firmness), bioactive compounds, and antioxidants of the cherry tomato during 21 days refrigerated storage. The result obtained indicates the promising substitute to the single washing technique for microbial safety as well as preserving the nutritional quality and enhancing the shelf life of cherry tomato.     

Assessment of sonotrode and tube reactors for ultrasonic pre-treatment of two different sewage sludge types

The effectiveness of tube and sonotrode reactors for the sonication of sewage sludge under identical conditions was compared for the first time. Despite the considerable structural differences, sonication with each ultrasonic reactor led to an accelerated degradation rate and an increased methane production within the first five days for the majority of the sewage sludge samples tested. On closer examination, however, it becomes clear that the investigated sonication systems are not equally suitable for the substrates considered. While the use of a sonotrode proved to be particularly advantageous for the treatment of waste activated sludge (+25% methane yield at 300 kJ/kg_TS), the use of a 2-inch tube reactor achieved the highest enhancement for low-intensity sonication in digested sludge (+22% methane yield at 300 kJ/kg_TS). With increasing energy input, more chemical oxygen demand was solubilized, but this did not result in an increase in methane yield for all samples. Sonication of waste activated sludge led to a significant reduction in viscosity of up to 50%, and a reduction of up to 60% was observed after sonication of digested sludge with low energy inputs. The study, therefore, demonstrates that the choice of the most suitable sonication system essentially depends on the properties of the sludge to be sonicated.     

Tertiary treatment of real abattoir wastewater using combined acoustic cavitation and ozonation

This work reports the influence of ultrasound alone and combined with ozone for the treatment of real abattoir wastewater. Three different frequencies were studied (44, 300 and 1000 kHz) at an applied power of 40 W. The injected ozone dose was fixed at 71 mg/L and the treatment time varied from 1 to 60 min. Using ultrasound alone, 300 kHz was the only frequency showing a reduction in chemical oxygen demand (COD, 18% reduction) and biological oxygen demand (BOD, 50% reduction), while no diminution in microbial content was measured for any of the frequencies studied. Combining ultrasound with ozone, on the contrary, led to a significant decrease in COD (44%) and BOD (78%) removal for the three frequencies under study. A complete inactivation of total coliforms (TC) was obtained, as well as a final value of 99 CFU/mL in total viable counts (TVC, 5 log reduction). That is, the ozonation-sonication combined system was the only treatment method (compared to sonication and ozonation alone) reaching direct discharge limits, as well as meeting drinking water standards for microbial disinfection (TC and TVC).     

Hydrogen storage in sonicated carbon materials

The hydrogen storage in purified single-wall carbon nanotubes (SWNTs), graphite and diamond powder was investigated at room temperature and ambient pressure. The samples were sonicated in 5 M HNO₃ for various periods of time using an ultrasonic probe of the alloy Ti-6Al-4V. The goal of this treatment was to open the carbon nanotubes. The maximum value of overall hydrogen storage was found to be 1.5 wt %, as determined by thermal desorption spectroscopy. The storage capacity increases with sonication time. The sonication treatment introduces particles of the Ti alloy into the samples, as shown by X-ray diffraction, transmission electron microscopy, and chemical analysis. All of the hydrogen uptake can be explained by the assumption that the hydrogen is only stored in the Ti-alloy particles. The presence of Ti-alloy particles does not allow the determination of whether a small amount of hydrogen possibly is stored in the SWNTs themselves, and the fraction of nanotubes opened by the sonication treatment is unknown. Received: 18 December 2000 / Accepted: 18 December 2000 / Published online: 9 February 2001     

Impacts of sonication and high hydrostatic pressure on the structural and physicochemical properties of quinoa protein isolate dispersions at acidic,neutral and alkaline pHs

Herein, 1 wt% quinoa protein isolate (QPI) was exposed to sonication using a 20 kHz ultrasonicator equipped with a 6 mm horn (14.4 W, 10 mL, up to 15 min) or high hydrostatic pressure (HHP, up to 600 MPa, 15 min) treatments at pH 5, pH 7, and pH 9. The changes to physicochemical properties were probed by SDS-PAGE, FTIR, free sulfhydryl group (SH), surface hydrophobicity (H₀), particle size and solubility. As revealed by SDS-PAGE, substantial amounts of 11S globulin participated in the formations of aggregates via SS bond under HHP, particularly at pH 7 and pH 9. However, protein profiles of QPI were not significantly affected by the sonication. Free SH groups and surface hydrophobicity were increased after the sonication treatment indicating protein unfolding and exposure of the embedded SH and/or hydrophobic groups. An opposite trend was observed in HHP treated samples, implying aggregation and reassociation of structures under HHP. HHP and sonication treatments induced a decrease in ordered secondary structures (random coil and β-turn) accompanied with an increase in disordered secondary structures (α-helix and β-sheet) as probed by FTIR. Finally, the sonication treatment induced a significant improvement in the solubility (up to ∼3 folds at pH 7 and ∼2.6 folds at pH 9) and a reduction in particle sizes (up to ∼3 folds at pH 7 and ∼4.4 folds at pH 9). However, HHP treatment (600 MPa) only slightly increased the solubility (∼1.6 folds at pH 7 and ∼1.2 folds at pH 9) and decreased the particle size (∼1.3 folds at pH 7 and ∼1.2 folds at pH 9). This study provides a direct comparison of the impacts of sonication and HHP treatment on QPI, which will enable to choose the appropriate processing methods to achieve tailored properties of QPI.     

Sonoelectrocatalytic decomposition of methylene blue using Ti/Ta2O5–SnO2 electrodes

Sonoelectrochemical decomposition of organic compounds is a developing technique among advanced oxidation processes (AOPs). It has the advantage over sonication alone that it increases the efficiency of the process in terms of a more rapid decrease in chemical oxygen demand (COD) and in total organic carbon (TOC) and accelerates electrochemical oxidation which normally requires a lengthy period of time to achieve significant mineralisation. Moreover the use of an electrocatalytic electrode in the process further accelerates the oxidation reaction rates. The aim of this study was to improve the decomposition efficiency of methylene blue (MB) dye by sonoelectrochemical decomposition using environmentally friendly and cost-effective Ti/Ta₂O₅–SnO₂ electrodes. Decolourisation was used to assess the initial stages of decomposition and COD together with TOC was used as a measure of total degradation. The effect of a range of sonication frequencies 20, 40, 380, 850, 1000 and 1176 kHz at different powers on the decolourisation efficiency of MB is reported. Frequencies of 850 and 380 kHz and the use of higher powers were found more effective towards dye decolourisation. The time for complete MB degradation was reduced from 180 min using electrolysis and from 90 min while carrying out sonolysis to 45 min when conducting a combined sonoelectrocatalytic experiments. The COD reduction of 85.4% was achieved after 2 h of combined sonication and electrolysis which is a slightly higher than after a single electrolysis (78.9%) and twice that of sonolysis (40.4%). A dramatic improvement of mineralisation values were observed within 2 h of sonoelectrocatalytic MB degradation. The TOC removal efficiency increased by a factor of 10.7 comparing to sonication alone and by a factor of 1.5 comparing to the electrolytic process. The energy consumption (kWh/m³) required for the complete degradation of MB was evaluated.     

Effects of thermal treatment and sonication on quality attributes of Chokanan mango (Mangifera indica L.) juice

Ultrasonic treatment is an emerging food processing technology that has growing interest among health-conscious consumers. Freshly squeezed Chokanan mango juice was thermally treated (at 90 °C for 30 and 60 s) and sonicated (for 15, 30 and 60 min at 25 °C, 40 kHz frequency, 130 W) to compare the effect on microbial inactivation, physicochemical properties, antioxidant activities and other quality parameters. After sonication and thermal treatment, no significant changes occurred in pH, total soluble solids and titratable acidity. Sonication for 15 and 30 min showed significant improvement in selected quality parameters except color and ascorbic acid content, when compared to freshly squeezed juice (control). A significant increase in extractability of carotenoids (4–9%) and polyphenols (30–35%) was observed for juice subjected to ultrasonic treatment for 15 and 30 min, when compared to the control. In addition, enhancement of radical scavenging activity and reducing power was observed in all sonicated juice samples regardless of treatment time. Thermal and ultrasonic treatment exhibited significant reduction in microbial count of the juice. The results obtained support the use of sonication to improve the quality of Chokanan mango juice along with safety standard as an alternative to thermal treatment.     

Bio-activity assessment of fruits using Generalized Difference and Parameterized Fujii method

In this research work, both qualitative and quantitative measurement of biospeckle activity of three Indian fruits namely apple, pear and tomato have been carried out using Generalized Difference and Parameterized Fujii methods. Different activity area of the fruits can be easily visualized through the spectral maps. The variation of activity level of the fruits during shelf life storage has been studied through activity graphs. Comparative studies of activities of all the fruits are also presented and relatively high activity was found in apple compared to pear and tomato.