Impact Of Ultrasound Pretreatment Research Articles

Impact of Ultrasound Pretreatment on Juice Yield and Bioactive Content in Juice Produced from Selected Berries Fruit.

The aim of the work was to investigate the effect of ultrasound application during juice pressing. The impact on pressing yield and extraction of bioactive compounds during production of juice from strawberry, blackcurrant and raspberry was evaluated. Juice pressing was carried out after four kinds of mash pretreatment. The tested objects were heated to 55 °C, treated by ultrasound, and/or macerated with an enzyme. The obtained juices were analyzed for the content of bioactive compounds and compared to the 'Control' sample, which was the juice pressed without any pretreatment. Although the results presented here do not conclusively show that enzymatic maceration can be completely replaced by the use of ultrasound, in the case of strawberry and raspberry fruit, juice yield after ultrasound treatment increased almost as much as after enzymatic maceration. Additionally, in the case of raspberry fruit, the antioxidant activity of the juice samples was definitely improved when ultrasound was used. The results from this experiment also showed that it is possible to separate the effect of temperature from the effect of mechanical and chemical actions in ultrasound treatment.

Impact of ultrasound pretreatment on banana chip production by convective drying using hot air: Consideration of shrinkage and variable effective mass diffusivity in the process description

AbstractIn this study, we used experimental analysis and numerical simulation to describe and compare the convective drying (CD) of banana slices, without and with pretreatment with ultrasound (US) at 25 kHz. Banana slices, with an average initial thickness of about 6.60 × 10−3 m and an average diameter of about 3.01 × 10−2 m, were subjected to CD at temperatures of 60, 70, and 80°C, with air speed of 1.5 m s−1. Considering such dimensions, the one‐dimensional diffusion equation in Cartesian coordinates was numerically solved by the finite volume method, using a fully implicit formulation (direct problem). A solver with a numerical solution was developed for the direct problem. This solver was coupled to an optimizer to determine the parameters a and b of functions that relate the effective moisture diffusivity (D) with the local moisture ratio, and also to determine the convective mass transfer coefficient (h) (inverse problem), considering the shrinkage. The proposed model was used to describe the data obtained. The results revealed that the drying rate increased in samples that were subjected to pretreatment with US, for each drying temperature. The best‐simulated results were those that related D to the local moisture ratio by means of a bcosh (aMR2) function. It could be observed that pretreatment with US allowed saving of time (and consequently energy) of 28.3%, 16.0%, and 12.4% at drying temperatures of 60, 70, and 80°C, respectively.Practical applicationsThe main contribution of this paper is to present a solver and an optimizer to determine the mass transfer properties considering the shrinkage during convective drying of banana pieces pretreated with ultrasound by the inverse problem. With the information obtained for the mass transfer properties and the proposed numerical model with a hyperbolic cosine type function for the effective moisture diffusivity, it is possible to more accurately determine the time and, therefore, the energy savings of processing banana chips pre‐treated with ultrasound.

Anaerobic co-digestion of food waste and cardboard in different mixing ratios: Impact of ultrasound pre-treatment on soluble organic matter and biogas generation potential at varying food to inoculum ratios

The aim of the present work is to investigate the impact of acetic acid assisted ultrasound pre-treatment of food waste (FW) and cardboard (CB) to overcome the barriers of substrate characteristics. Anaerobic co-digestion (ACoD) experiments were conducted with FW and CB in the mixing ratios of 100:0, 80:20, 60:40 and 50:50 at a food to inoculum (F/I) ratio of 1:1 and 1:2 to investigate its impact on biogas yield, volatile solids (VS) removal, solubilization of organic matter and the specific energy (SE) required. Results revealed that the biogas yield obtained from ultrasound pre-treated samples regardless of mixing ratio was higher at a F/I ratio of 1:2 compared to 1:1. The formation of bubbles, cavities and floc matrix significantly increased and the particle size decreased from 100 μm to 10 μm for FW:CB of 60:40 and 50:50 after pre-treatment. Ultrasound pre-treatment for 45 min was adequate for FW:CB of 100:0 and 80:20 while it was 60 min for 60:40 and 50:50 for increased sCOD between 37 % - 53 %. The VS removal efficiencies increased between 3–15 % from pre-treated samples compared to untreated. The CB mixing ratio is inversely related to SE while directly related to sCOD. Overall, during ACoD of FW and CB, the FW:CB of 80:20 gave a higher biogas yield of 471 mL/g VSadded followed by 60:40 and 50:50.

Effect of ultrasound pretreatment on the physicochemical properties and simulated gastrointestinal digestibility of micellar casein concentrates

In this study, microfiltered casein micelle retentates were treated with sonication within 15 min prior to spray drying, and the impact of ultrasound pretreatment on the physicochemical, functional, and digestion properties of the resultant micellar casein concentrates were investigated. The results showed that the intrinsic fluorescence intensities of casein samples increased after extending the ultrasound pretreatment time from 2 to 6 min, but decreased if pretreatment time was further prolonged; this was also true for the oil absorption capacity. Additionally, there was a reduction in particle size and thermal stability and an increase in the solubility of pretreated samples in the pH range of 4–8 compared with controls. Bulk and tapped density values decreased after extending the sonication time from 2 to 4 min, but increased if sonication time was further prolonged. No significant changes in the secondary structure of the samples were observed after sonication. An obvious disintegration of micellar casein particles was observed by scanning electron microscopy following ultrasound pretreatment times up to 10 min, resulting in improved digestibility in simulated intestinal fluid. Thus, we concluded that prolonged ultrasound pretreatment facilitates enhanced digestion of micellar casein concentrate and its products.

Effect of multi-frequency counter-current S type ultrasound pretreatment on the enzymatic hydrolysis of defatted corn germ protein: Kinetics and thermodynamics

Abstract In this paper, the impact of ultrasound pretreatment on the kinetics and thermodynamics of defatted corn germ protein (DCGP) enzymatic hydrolysis was evaluated. The enzymatic hydrolysis kinetics and thermodynamics were studied for traditional method and ultrasonic pretreatments with a single-frequency counter-current S type (20 KHz) (SFU) and a multi-frequency counter-current S type (20, 28, 35 and 40 KHz) (MFU). The results showed that the traditional, SFU and MFU pretreated enzymatic hydrolysis of DCGP followed the First-order kinetic model. Again, the SFU and MFU pretreatments enhanced the enzymatic hydrolysis of DCGP. Compared to traditional enzymatic hydrolysis, the reaction rate constant values were increased by 50.0%, 54.7%, 47.8% and 52.3% for SFU pretreated enzymatic hydrolysis, and 58.0%, 58.5, 53.6% and 54.7% for MFU pretreated enzymatic hydrolysis at 20, 30, 40 and 50 oC respectively. Also, the results showed that the SFU and MFU ultrasound pretreatments of DCGP reduced the thermodynamic parameters which included the activation energy (Ea), enthalpy (ΔH), entropies (ΔS) and Gibbs free energy (ΔG) in enzymatic hydrolysis reaction.

Impact of ultrasound pretreatment on hydrolysate and digestion products of grape seed protein

The effects of ultrasound pretreatment with different working modes, including mono frequency ultrasound (MFU), simultaneous dual frequency ultrasound (SDFU) and alternate dual frequency ultrasound (ADFU) using energy-gather counter flow ultrasound equipment, on the degree of hydrolysis (DH) of grape seed protein (GSP) hydrolysate and IC50 of GSP digestion products were studied. Amino acid composition analysis (AACA), ultraviolet–visible (UV) spectroscopy and atomic force microscopy (AFM) of GSP with different ultrasound pretreatments were measured. The results showed that MFU, SDFU and ADFU pretreatments improved the DH and reduced the IC50 of GSP significantly (P < .05). The MFU of 20 kHz and SDFU of 20/40 kHz showed higher ACE inhibitory activity within the MFU and SDFU groups, respectively. ADFU of 20/35 kHz produced the highest ACE inhibitory activity among the three working modes (MFU, SDFU and ADFU). AACA showed that all the working modes of the ultrasound pretreatment could increase the amount of hydrophobic amino acids and the total amino acids. The changes in UV spectra and amino acid analysis indicated the unfolding of protein structure and exposure of more hydrophobic groups by SDFU and ADFU pretreatments. AFM analysis of the GSP indicated that the microstructures were destroyed and the particle size reduced after dual-frequency ultrasound pretreatments. Therefore, energy-gather counter flow ultrasound pretreatment is an effective method to improve the DH and reducing the IC50 due to the changes of molecular conformation and effects on the microstructure by sonochemistry of GSP. In conclusion, it is necessary to select the frequency and working modes of ultrasound pretreatment for the preparation of ACE inhibitory peptide of GSP.

The impact of ultrasound pretreatment on the enzymatic hydrolysis of cellulose from sugar beet shreds: Modeling of the experimental results

This article investigates the impact of ultrasound as pretreatment for enzymatic hydrolysis of cellulose from sugar beet shreds and uses modeling of the experimental results. Ultrasound pretreatment with different power input, duration, duty cycle, and solids load was applied to sugar beet shreds. Ultrasound under investigated conditions provided substrates with different characteristics. At applied conditions, ultrasound caused up to 28% material solubilization while cellulose recovery was approximately 90%. Pretreated substrates had multiple times higher values of water retention (WRV) than untreated one. Ultrasound pretreated sugar beet shreds were more susceptible to cellulases adsorption than the untreated ones having 1.4 to 15 times higher maximum adsorption capacity (σ). Statistical modeling of the results of enzymatic hydrolysis revealed that parameters with significant influence on the reducing sugars yield were interaction between σ and cellulose recovery, then σ and WRV as mutually independent parameters, as well as interaction between WRV and σ. The highest achieved yield of cellulose hydrolysis was 3.7 times higher than that obtained with untreated sugar beet shreds and it amounted approximately 780 mg/g cellulose. © 2017 American Institute of Chemical Engineers Environ Prog, 36: 1164–1172, 2017

Impact of ultrasound pretreatment on whey protein hydrolysis by vegetable proteases

Abstract The ultrasound treatment on whey protein before enzymatic hydrolysis using vegetable proteases was studied. Ultrasound density, temperature, and pretreatment time effects were evaluated on enzymatic degree of hydrolysis, release of Angiotensin I-Converting Enzyme (ACE) inhibitors, and antioxidant activity of the hydrolysates generated. In addition, thermal properties as measured by Differential Scanning Calorimetry (DSC) and changes in secondary structure by circular dichroism (CD) were measured. The results showed that ultrasound density was the only factor that exerted a significant effect on proteolysis increasing the ACE inhibition by 13% and a 95% reduction of hydrolysis time in bromelain hydrolysates, but did not improve the ACE inhibition on papain hydrolysates. Observed changes in denaturation enthalpy (ΔH), reduction of reactive thiol groups, and changes in secondary structure suggest protein rearrangements and aggregate formation. The effect of ultrasound on the whey protein structure produced changes increasing the bioactivity of hydrolysates that could enhance the enzymatic hydrolysis process. Industrial relevance Whey proteins are an important source of bioactive peptides. However, due to their globular structure, they are a complex substrate for enzymatic hydrolysis. Ultrasonic pretreatment could induce changes increasing susceptibility to enzymatic hydrolysis resulting in production of more bioactive peptides. Therefore, treatment of whey proteins with ultrasound waves before enzymatic hydrolysis, offers higher efficiency of enzymatic bioconversion of proteins and production of new biologically active peptide mixtures.