scholarly journals Ohmic heating of pomegranate juice: Electrical conductivity and pH change

2013 ◽  
Vol 12 (2) ◽  
pp. 101-108 ◽  
Author(s):  
Hosain Darvishi ◽  
Mohammad Hadi Khostaghaza ◽  
Gholamhassan Najafi
2017 ◽  
Vol 39 ◽  
pp. 241-246 ◽  
Author(s):  
Filiz Icier ◽  
Hasan Yildiz ◽  
Serdal Sabanci ◽  
Mutlu Cevik ◽  
Omer Faruk Cokgezme

2020 ◽  
Vol 861 ◽  
pp. 213-217
Author(s):  
Sumuncharee Suyraksa ◽  
Pitiya Kamonpatana ◽  
Noppadon Kerddonfag ◽  
Amporn Sane ◽  
Vanee Chonhenchob

This study was aimed to develop conductive packaging for ohmic heating. Polypropylene (PP) was mixed with conductive material (CM) in the ratios of 70:30 (CM30), 75:25 (CM25), and 80:20 (CM20) (w/w), then the conductive bottles were developed using extrusion blow molding process. The bottles were suspended in different sodium sulfate (Na2SO4) solutions (0.2, 0.3, and 0.5% w/w) as a transmitting current medium for ohmic heating and heated for 8 min. The CM30 and CM 25 had the highest electrical conductivity compared to the CM20, however the CM20 exhibited best processability, hence it was selected to be used for ohmic heating of orange juice. Different concentrations of Na2SO4 solutions had the effects on ohmic heating. The CM20 bottle suspended in 0.2% Na2SO4 solution resulted in the most uniform heating and suitable for ohmic processing of orange juice. The new conductive bottles developed could potentially be used for beverage processing by ohmic heating.


2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
M. E. Guerra-Valle ◽  
J. Moreno ◽  
S. Lillo-Pérez ◽  
G. Petzold ◽  
R. Simpson ◽  
...  

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.


2015 ◽  
Vol 8 (9) ◽  
pp. 1904-1913 ◽  
Author(s):  
Yinzhe Jin ◽  
Yu-dong Cheng ◽  
Mika Fukuoka ◽  
Noboru Sakai

Author(s):  
Lam-Lam Wong ◽  
Yong-Wei Xu ◽  
Zhan-Hui Lu ◽  
Li-Te Li

Electrical conductivity of starch suspension during ohmic heating was applied to analyze the starch gelatinization process. Native starches from wheat, corn, rice, potato, sweet potato, and pea were prepared on a starch to water ratio of 1:3 (w/w) with adding 0.05 M potassium chloride. A laboratory scale ohmic heating setup was designed to heat the starch suspension from room temperature to 90°C at a controlled heating rate of 10°C/min operating at 50 Hz and 110 V. The results show that starch gelatinization temperatures could be precisely calculated from electrical conductivity of starch suspension during ohmic heating process. The starch gelatinization temperatures based on ohmic heating were comparable to those measured by differential scanning calorimetry (DSC). Highly significant correlation of onset temperature (R=0.9972) and peak temperature (R=0.9950) were observed. The ohmic heating method could provide an alternative way to DSC with a promising potential for on-line and rapid evaluation of starch gelatinization temperatures.


2011 ◽  
Vol 7 (5) ◽  
Author(s):  
Mostafa Keshavarz Moraveji ◽  
Emad Ghaderi ◽  
Reza Davarnejad

In this article, the effects of Ohmic heating process conditions on electrical conductivity and heat transfer were investigated. In order to study the Ohmic heating process, various hydrocolloid solutions containing starch in water with concentrations of 4–8% in the static cells were used. Temperature increments increased electrical conductivity of the solution, linearly. The concentration of dispersed solid particles in the solution caused a progressive trend in time-temperature curve for hydrocolloid solutions (with concentrations of 4, 5.5 and 8%) without electrolytes. The electrical conductivity was raised by increasing temperatures. In order to consider the salinity impact on electrical conductivity and the heating rate, sodium chloride (with concentrations of 1–0.25%) was added to the solution. It was observed that the salt addition to the system had a major effect on electrical conductivity and time-temperature curves. The pH level was modified with Citric acid addition, and the influence of pH level on the time-temperature curves and heating rates were investigated. The Citric acid addition had no on significant effect on the time-temperature curves.


2012 ◽  
Vol 79 (1) ◽  
pp. 10-17 ◽  
Author(s):  
Su-Yeon Lee ◽  
Sangryeol Ryu ◽  
Dong-Hyun Kang

ABSTRACT The effect of frequency of alternating current during ohmic heating on electrode corrosion, heating rate, inactivation of food-borne pathogens, and quality of salsa was investigated. The impact of waveform on heating rate was also investigated. Salsa was treated with various frequencies (60 Hz to 20 kHz) and waveforms (sine, square, and sawtooth) at a constant electric field strength of 12.5 V/cm. Electrode corrosion did not occur when the frequency exceeded 1 kHz. The heating rate of the sample was dependent on frequency up to 500 Hz, but there was no significant difference ( P > 0.05) in the heating rate when the frequency was increased above 1 kHz. The electrical conductivity of the sample increased with a rise in the frequency. At a frequency of 60 Hz, the square wave produced a lower heating rate than that of sine and sawtooth waves. The heating rate between waveforms was not significantly ( P > 0.05) different when the frequency was >500 Hz. As the frequency increased, the treatment time required to reduce Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium to below the detection limit (1 log CFU/g) decreased without affecting product quality. These results suggest that ohmic heating can be effectively used to pasteurize salsa and that the effect of inactivation is dependent on frequency and electrical conductivity rather than waveform.


Desalination ◽  
2010 ◽  
Vol 260 (1-3) ◽  
pp. 9-17 ◽  
Author(s):  
A.M. Assiry ◽  
M.H. Gaily ◽  
M. Alsamee ◽  
A. Sarifudin

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