Ohmic Processing: Temperature Dependent Electrical Conductivities of Lemon Juice

Darvishi, Hosain; Hosainpour, Adel; Nargesi, Farzad; Khoshtaghaza, Mohammad Hadi; Torang, Hosain

doi:10.5539/mas.v5n1p209

Cited by 49 publications

(33 citation statements)

References 25 publications

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“…There are several published patents about the usage of ohmic treatments on several food materials such as; strawberry (Allali et al (2008); Sarang et al (2008); Castro et al (2004)); red apple, golden apple, peach, pear and pineapple ); tomato soup (Jun and Sastry (2005)); apricot and peach purees Icier and Ilicali (2005a)); sour cherry juice (Icier Icier and Ilicali (2004)); tylose (Icier and Ilicali (2005b)); seawater (Assiry et al (2010a); Assiry (2011)); lemon juice (Darvishi et al (2011)); milk (Stancl and Zitny. 2010;Bansal and Chen.…”

Section: Introductionmentioning

confidence: 99%

The process of producing tomato paste by ohmic heating method

et al. 2014

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In this study, the effect of ohmic heating technique on electrical conductivity, water evaporation rate, heating rate, colour parameters, pH and energy consumption of tomato samples was investigated. Ohmic heating was accomplished till the moisture content of the tomato samples reduced from initial moisture content of as 9.33 (dry basis) to a safer level of 2.2. The results of the nonlinear mathematical model including the effects of voltage gradient level and the temperature on the electrical conductivity changes had good agreement (R≥ 0.955) with the experimental data. Also, it was observed that the electrical conductivity increased along with concentration of tomato samples. The range of electrical conductivity during ohmic heating was 3.19-8.95 (S/m). It was found that processing time decreased from 28.32 to 4.3 min over the voltage gradient range studied (6 to 14 V/cm), which resulted in decreased specific energy consumption from 4.63 to 3.05 (MJ/kg water). Due to increasing of heating rate and water evaporation rate at high voltage gradient, the change of the pH was limited. Samples processed in high voltage gradient had higher L*, b* and hue angle (h), lower a* and Chroma (C) values as compared to low voltage gradient. The optimum value of processing time, pH, colour, specific energy consumption was obtained at 14 V/cm voltage gradient level.

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Section: Introductionmentioning

confidence: 99%

The process of producing tomato paste by ohmic heating method

et al. 2014

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“…At both electric field strengths, the temperature of the medium showed a minor increase throughout the operations (∆T < 2 o C). A minor temperature increase in the medium indicated that distilled water had a lower electrical conductivity compared to brine (Darvishi et al, 2011;Hayashi, 2004). On the other hand, a saline medium caused rapid meat thawing, and the total thawing time decreased to under 1 h (~52 min) for 0.2% NaCl and approached about 30 min for 2% NaCl (Fig.…”

Section: Resultsmentioning

confidence: 99%

Applications of Low-voltage Ohmic Process Combined with Temperature Control System to Enhance Salting Process of Pork

Hong¹,

Chun²,

Choi³

2012

Korean Journal for Food Science of Animal Resources

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This study investigated the effects of a low-voltage ohmic heating process (2.5 and 3.8 V/cm) on the thawing characteristics and NaCl diffusion of pork. The thawing rate of pork was dependent on the applied voltages and brine salinities, and few differences were obtained in pork quality parameters (color, water-holding capacity, and shear force) regarding the different treatments. The NaCl concentration of pork after ohmic thawing was higher than that following brineimmersion thawing, however, the NaCl diffusion did not differ from when fresh meat was immersed in brine. For application of the ohmic process in fresh pork, various ohmic pulses were generated in order to prevent the meat from overheating, and the results indicated that the ohmic process was a better way to enhance NaCl diffusion compared with immersing pork at high temperature. Although the mechanisms involved in NaCl diffusion at low-voltage electric field strength were unclear, the present study demonstrated that the ohmic process has a potential benefit in the application of meat processing.

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“…Ohmic heating of tomato paste, at 6V/cm, showed that the time taken to reach 96 C was 235s; whereas at 14V/cm the time taken to reach the same temperature was 38s [15] . A bubbling temperature of upto 90 C was reached when grape juice was ohmic heated at 20 to 40 V/cm [17] .…”

Section: Effect Of Temperature and Voltage Gradient On Rate Of Ohmic mentioning

confidence: 99%

“…At 13.33 V/ cm, the time required to heat the pulp without sugar and with 10%, 30% and 50% sugar was observed to be 90s, 120s, 240s and 540s.Similar observation was done at 20 V/cm and 26.66 V/cm. A bubbling temperature of 74 C was reached within 45s when lemon juice was ohmically heated at 30-55V/cm [15] . The ohmic heating of tomato juice at 50-70 V/cm 48s to reach a temperature of 80 C [16] .…”

Section: Effect Of Temperature and Voltage Gradient On Rate Of Ohmic mentioning

confidence: 99%

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Stability and Storage Studies on Banana pulp by Ohmic Heating and Conventional Heating

Poojitha¹,

Athmaselvi²

2016

Biosci., Biotech. Res. Asia

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The demand for fresh foods with longer shelf life is increasing day by day. The conventional pasteurization reduces the microbial count but easily affects the organoleptic properties. In order to enhance the shelflife and quality of the product ohmic heating technique is used. Ohmic heating is a fast heating method for food products. This is a food processing technique in which the liquid or semi-solid foods are sterilized without any physical damage as caused in conventional heating. In ohmic heating processes, foods are made part of an electric circuit through which alternating current flows, causing heat to be generated within the foods due to the electrical resistance of the foods. In this study, banana pulp without sugar and with different concentrations of sugar is ohmically heated and the changes in physiochemical properties are compared with that of conventional heating. The electrical conductivity, pH, total soluble solids, acidity before and after heat treatment were also analysed. Meanwhile, the pulp was stored in refrigeration temperature without adding preservatives and the shelf life of the ohmic heated and conventional heated banana pulp was also studied. Consequently, it is been found that ohmic heated pulp has maximum shelf life than conventionally heated pulp.

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Ohmic Processing: Temperature Dependent Electrical Conductivities of Lemon Juice

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Cited by 49 publications

References 25 publications

The process of producing tomato paste by ohmic heating method

The process of producing tomato paste by ohmic heating method

Applications of Low-voltage Ohmic Process Combined with Temperature Control System to Enhance Salting Process of Pork

Stability and Storage Studies on Banana pulp by Ohmic Heating and Conventional Heating

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