scholarly journals Ohmic heating/vacuum impregnation treatments on osmodehydrated apples enriched in polyphenols from concentrated pomegranate juice

2018 ◽  
Author(s):  
Jorge Moreno ◽  
P. Zúñiga ◽  
M. E. Guerra ◽  
K. Mella
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Water Content ◽  
Ohmic Heating ◽  
Pomegranate Juice ◽  
Vacuum Impregnation ◽  
Polyphenol Content ◽  
Osmotic Treatment ◽  
Reduced Water ◽  
Improve Mass Transfer

The aim of this work was to study the combination of osmodehydration (OD), coupled with Ohmic Heating (OH) and Pulsed Vacuum (PV) and to introduce natural compounds from a cryoconcentrated pomegranate juice (47°Brix) at 30, 40 and 50 °C into apple matrix, during 180 min. PV was performed at 50 mbar for 5 min at the beginning of the process and OH generates an electric field of 6.6 V/cm. The results indicated that treatments reduced water content and increase polyphenol content of apples, evidencing that the osmotic treatment improve mass transfer, especially when they are applied together at higher temperatures. Keywords: Ohmic heating; pulsed vacuum; cryoconcentration; enriched; pomegranate.

scholarly journals Studies on the Effect of Mass Transfer in Vacuum Impregnation on the Bioactive Potential of Apples

Molecules ◽  
2019 ◽  
Vol 24 (19) ◽  
pp. 3533 ◽  
Author(s):  
Marta Pasławska ◽  
Bogdan Stępień ◽  
Agnieszka Nawirska-Olszańska ◽  
Kinga Sala
Keyword(s):  
Mass Transfer ◽  
Antioxidant Capacity ◽  
Vacuum Impregnation ◽  
Process Conditions ◽  
Mass Variation ◽  
Polyphenol Content ◽  
Solid Gain ◽  
Vacuum Level ◽  
Apple Tissue ◽  
Bioactive Potential

The purpose of the study was to evaluate the efficiency of mass transfer during vacuum impregnation (VI) of apple tissue by different process conditions. VI was carried out in two stages: Vacuum (4, 6, or 8 kPa maintained at time 10, 20, 30, 40, 60, and 80 s) and atmospheric (4 min under atmospheric pressure). As infiltration liquids, fresh squeezed apple-pear juice (J), 3% citric acid solution (C), and distilled water (DW) were used. Mass transfer was analyzed based on three factors: Mass variation (MV), dry mass variation (DMV), and solid gain (SG). The outflow of native components and inflow of infiltration liquid has been described by mathematical models. The polyphenol content and antioxidant capacity (ABTS+, FRAP) were evaluated as the bioactive potential factors confirming native component outflow and incorporation of liquid molecules into an apple tissue. It was found that during VI of an apple tissue, intensive mass transfer occurred: Native components of fruit tissue outflowed and external ingredients of impregnation liquid inflowed into the material with the intensity proportional to the vacuum level and process time. The most beneficial conditions of apple cube VI were noticed at a vacuum level of 4 kPa for a minimum of 40 s, which is when the highest polyphenol content and antioxidant capacity occurred.

scholarly journals Enrichment of Apple Slices with Bioactive Compounds from Pomegranate Cryoconcentrated Juice as an Osmodehydration Agent

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
M. E. Guerra-Valle ◽  
J. Moreno ◽  
S. Lillo-Pérez ◽  
G. Petzold ◽  
R. Simpson ◽  
...  
Keyword(s):  
Electric Field ◽  
Bioactive Compounds ◽  
Ohmic Heating ◽  
Soluble Solids ◽  
Pomegranate Juice ◽  
Total Flavonoids ◽  
Fresh Sample ◽  
Total Anthocyanin ◽  
Apple Slices ◽  
Combined Technique

Pomegranate juice is an important source of bioactive compounds, and cryoconcentrated juice is an interesting osmodehydration agent to enrich a vegetal matrix. This investigation aimed to incorporate bioactive compounds from pomegranate cryoconcentrated juice into apple slices using osmodehydration (OD) assisted by pulse vacuum (PV) and ohmic heating (OH). The apple slices (3 × 4 × 0.5 cm) were osmodehydrated using a 47 °Brix pomegranate cryoconcentrated juice at 30, 40, or 50°C for 180 min with an electric field of 6.66 V/cm (50 V) and a 5 min pulsed vacuum. Over the time, all of the treatments applied to the apple slices increased the soluble solids and bioactive compounds compared with the fresh sample. PVOD/OH at 50°C had the highest content of total anthocyanin during processing, and the best results for the total flavonoids were obtained with OD/OH at 50°C and 40°C. The osmodehydration assisted by pulse vacuum and ohmic heating using a cryoconcentrated juice is a useful combined technique to acquire enriched vegetal samples with bioactive compounds.

scholarly journals Optimizing sludge dewatering with an alternate pressure and electric field

2021 ◽  
Author(s):  
Yunyi Li ◽  
Xinmiao Huang ◽  
Ying Wei ◽  
Yangsheng Liu
Keyword(s):  
Energy Consumption ◽  
Electric Field ◽  
Water Content ◽  
Ohmic Heating ◽  
Promising Method ◽  
Sludge Dewatering ◽  
Dewatered Sludge

Abstract Sludge dewatering is a prerequisite for the subsequent utilization of sludge. However, the existing mechanical dewatering cannot achieve satisfactory water content (< 60%). Herein, pressure and electric dewatering in alternate operation (P/EDWalt) was proposed to improve dewatering efficiency. Compared with conventional simultaneous mode, P/EDWalt performed better in sludge dewatering. Its optimal dewatering conditions were voltage of 30 V for 20 min in two electric dewaterings, and pressure of 0.04, 0.07 and 0.10 MPa in three pressure dewaterings. Such conditions, the water content of sludge was reduced from 83.7% to 53.3%, the dewatering efficiency was 36.3%, and the energy consumption was 0.138 kWh/kgtotal removed water. These phenomena such as electroosmosis, the ohmic heating and electrophoresis facilitated the removal of water in sludge, and the dewatered sludge has good reusability in incineration, landfill and agriculture. Therefore, P/EDWalt could serve as a promising method for the sludge dewatering.

scholarly journals Effects of Ultrasound on Fermentation of Glucose to Ethanol by Saccharomyces cerevisiae

Fermentation ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Luis Huezo ◽  
Ajay Shah ◽  
Frederick Michel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mass Transfer ◽  
Glucose Uptake ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Biofuel Production ◽  
Inhibitory Effects ◽  
Negative Effects ◽  
Intraparticle Mass Transfer ◽  
Improve Mass Transfer

Previous studies have shown that pretreatment of corn slurries using ultrasound improves starch release and ethanol yield during biofuel production. However, studies on its effects on the mass transfer of substrates and products during fermentation have shown that it can have both beneficial and inhibitory effects. In this study, the effects of ultrasound on mass transfer limitations during fermentation were examined. Calculation of the external and intraparticle observable moduli under a range of conditions indicate that no external or intraparticle mass transfer limitations should exist for the mass transfer of glucose, ethanol, or carbon dioxide. Fermentations of glucose to ethanol using Saccharomyces cerevisiae were conducted at different ultrasound intensities to examine its effects on glucose uptake, ethanol production, and yeast population and viability. Four treatments were compared: direct ultrasound at intensities of 23 and 32 W/L, indirect ultrasound (1.4 W/L), and no-ultrasound. Direct and indirect ultrasound had negative effects on yeast performance and viability, and reduced the rates of glucose uptake and ethanol production. These results indicate that ultrasound during fermentation, at the levels applied, is inhibitory and not expected to improve mass transfer limitations.

scholarly journals Research on Electromagnetic Sensitivity Properties of Sodium Chloride during Microwave Heating

2020 ◽  
Vol 39 (1) ◽  
pp. 54-62
Author(s):  
Hua Chen ◽  
Junjiang Chen ◽  
Weijun Wang ◽  
Huan Lin
Keyword(s):  
Sodium Chloride ◽  
Electric Field ◽  
Water Content ◽  
Heating Rate ◽  
Microwave Heating ◽  
Resonant Cavity ◽  
Relative Dielectric Constant ◽  
Heating System ◽  
Heating Process ◽  
Heating Efficiency

AbstractThe multimode resonant cavity is the most common cavity. The material often shows on selective heating performance during the heating process due to the effect of microwave heating having a closely relationship with the electromagnetism parameters. This paper is based on finite difference time domain method (FDTD) to establish the electromagnetic-thermal model. The electromagnetic sensitivity property parameters of sodium chloride including relative dielectric constant, loss angle tangent and water content of sodium chloride is studied during the heating and drying process. The heating rate and the electric field distribution of sodium chloride, at the different water content, were simulated with the electromagnetic characteristic parameters changing. The results show that with the electromagnetic sensitivity property parameters varying, the electric field strength, heating rate and steady-state temperature of the heating material will all have a variety in the cavity. Some measures are proposed to improve the heating efficiency and ensure the stability of the microwave heating system in the industrial application.

Modeling Vapor Transport in a Hollow Fiber Membrane Humidifier Using ε-NTU Approach

2020 ◽  
Author(s):  
Hoang Nghia Vu ◽  
Xuan Linh Nguyen ◽  
Sangseok Yu
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Fuel Cell ◽  
Relative Humidity ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Water Content ◽  
Vapor Transport ◽  
Overall Mass Transfer Coefficient ◽  
Mass Exchanger

Abstract In a fuel cell vehicle, the water content of the gas supply within certain ranges plays a key role in improving the performance of a proton exchange membrane. The lower limit of water content in the air supply is to avoid the problem of drying-out, while the upper prevents flooding. Water management can be accomplished by a membrane humidifier which allows water vapor to permeate the mixture from the side having the higher water concentration, moving to the other side of the membrane. In this study, the variation in water content collected at the outlet of a membrane humidifier is investigated with a one-dimensional mass exchanger model and various operating variables. The vapor concentration of outlet flows is affected by operating temperature and relative humidity of the membrane humidifier. Relative humidity of the dry side at the point of outlet flow, to be supplied to the fuel cell module, is the key characteristic. The analogy of the effectiveness-NTU approach for heat transfer is used to analyze the characteristics of the mass exchanger. Mass flux through the membranes is estimated with an overall mass transfer coefficient which represents vapor transport characteristics moving through the membrane module. This coefficient has a similar role to the overall heat transfer coefficient in heat exchanger analysis. This parametric study is conducted to understand the effects of different variables. The Effectiveness-NTU methodology of mass transfer uses the overall mass transfer coefficient and the mass transfer rate, as evaluated experimentally. Simulink software is then employed to deliver outcomes of the model for different operating conditions.

scholarly journals MHD Mixed Convection Flow over a Permeable Vertical Plate with Buoyancy and Soret Effects

2012 ◽  
Vol 11 (3) ◽  
pp. 51-76
Author(s):  
J Prakash ◽  
B Rushi Kumar ◽  
R Sivaraj
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Mixed Convection ◽  
Vertical Plate ◽  
Ohmic Heating ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Governing Equations ◽  
Transfer Coefficients ◽  
Transfer Equations

This study examines the problem of steady, MHD, mixed convection flow of an incompressible viscous fluid past a semi-infinite vertical permeable plate with slip condition at the boundary layer. The flow field is exposed to the influence of buoyancy, Ohmic heating and Soret effects. The governing equations include the continuity, linear momentum, energy and mass transfer equations which are solved analytically by using perturbation method. The results of this parametric study on the velocity, temperature and concentration distributions are shown graphically and the physical aspects of the problem are highlighted and discussed. The effect of shear stress, rate of heat and mass transfer coefficients at the channel walls are displayed in tables.

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