• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1577-1582
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• 1999

Carrot juice inoculated with $2\;{\times}\;10^8\;cfu/mL$ of Escherichia coli was treated with pulsed electric fields(PEF) for the purpose of a development of new cold pasteurization processes. Inactivation of E. coli in carrot juice increased with increase in intensity of the electric field strength and treatment time. The cells were suspended at concentration of ca. $2\;{\times}\;10^8$ cells per ml. A reduction of 4D was obtained at 40 kv/cm and 256 exponential decay pulses at room temperature. Critical electric field strength(Ec) and treatment time(tc) needed for inactivation of E. coli were 11.74 kV/cm and $3.6\;{\mu}s$ at room temperature, respectively. The combination of PEF and thermal treatment inactivated E. coli more effectively. The reductions of up to 5.5D were observed when the carrot juice was treated with PEF of 22.5 kV/cm and $205\;{\mu}s$ at $50^{\circ}C$. PFF treatment did not effect in color, pH, $^{\circ}Brix$, titratable acidity and ${\alpha}-,\;{\beta}-carotene$ contents of carrot juice.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.871-878
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• 2004

Pulsed electric fields(PEF) technology is one of the latest nonthermal methods of food processing for obtaining safe and minimally processed foods. This technology can be effectively explored for obtaining safe food with minimum effect on nutritional, flavor, rheological and sensory qualities of food products. The process involves the application of high voltage(typically 20 ${\sim}$ 80 kv/cm) to foods placed between two electrodes. The mode of inactivation of microorganism; by PEP processing has been postulated in term; of electric breakdown and electroporation. The extent of destruction of microorganisms in PEF processing depends mainly on the electric field strength of the pulses and treatment time. For each cell types, a specific critical electric field strength and specific critical treatment time are required depending on the cell characteristics and the type and strength of the medium where they have been present. The effect also depends on the types of microorganisms and their phase of growth. A careful combination of processing parameters has to be selected for effective processing. The potential applications of PEF technology are numerous ranging from biotechnology to food preservation. With respect to food processing, it has already been established that, the technology is non-thermal in nature, economical and energy efficient, besides providing minimally processed foods. This article gives a brief overview of this technology for food processing applications.

• Korean Journal of Food Science and Technology
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• v.31 no.2
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• pp.410-415
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• 1999

Yakju was sterilized with high-voltage pulses of short time of a continuous pulsed electric field (PEF) system. The initial microbial counts of Yakju were $2.2{\times}10^{5}$ CFU/mL for total aerobes. The pH, acidity and electric conductivity of Yakju were 3.82, 0.37% and 1.24 mS/cm, respectively. Yakju was treated with exponential-wave formed electric pulses of 100 Hz for $0{\sim}4000{\mu}s$ under the field strength of $20{\sim}35\;kV/cm$. The lethal effect of electric fields on microorganisms was resulted from the breakdown of the cell membrane induced by the transmembrane electric potential. The critical values of the external field for the sterilization were 16.0 kV/cm for total aerobes. Logarithmic survival rates decreased linearly at low electric field strength, but curvilinearly at high electric field strength with treatment time. The sterilization of Yakju was more largely affected by the electric field strength than by the treatment time. Any changes in pH, acidity, and the growth of microorganisms were not found in the PEF treated Yakju during the storage at both $4^{\circ}C\;and\;30^{\circ}C$.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.46 no.3
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• pp.231-241
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• 2020

In this study in order to develop new approaches we investigated using high voltage pulsed electric fields (PEF) technology to reduce the risks, protect the phyto-constituents and improve skin biological activities. After preparing a Chaga mushroom (Inonotus obliquus) extracts pretreated with PEF, components measurement and skin efficacy evaluation were performed. As a result of the content measurement, the content of polysaccharide and polyphenol were higher in the order of extracts treated with 50 Hz and 25 Hz at 0.5 kV/cm, and the content of protein was the highest in extracts treated with 25 Hz at 0.5k V/cm. Similar to the results of the polyphenol measurements, extracts treated with 25 Hz and 50 Hz at 0.5 kV/cm showed leading DPPH scavenging ability. The cell protection effect against sodium dodecyl sulfate (SDS) and UVB was finest in extracts treated with 25 Hz at 0.5 kV/cm, which had the highest protein content. And the hyaluronic acid synthesis was leading in extracts treated with 50 Hz and 100 Hz at 0.5 kV/cm. Therefore, the active ingredient of the high-voltage PEF pre-treatment Chaga mushroom extract can be developed as a functional material with cell protection and moisturizing effect, and such green technology is expected to be used in various fields of cosmetics and material development.

• Food Science and Preservation
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• v.6 no.4
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• pp.521-529
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• 1999

The high influx of imported fruits into Korea is threatening to price and quality competition of domestic fruits. This investigation was conducted to raise price and quality competition of domestic fruits and to develop new products. The scale of production and processing, amount of processing and new processing technology were discussed. The area of cultivation land as well as the rate of processing is decreasing annually, an item of processing is limited to several kinds. Accordingly in this study, the status of production and manufacturing of some fruits and the new processing technologies such as high voltage pulsed electric fields, high hydrostatic pressure, ohmic heating, membrane separation and microwave treatment have investigated to fruit processing. Consequently, the minimal processing technology has to take advantage of various agricultural products in the food industry.

• Korean Journal of Food Science and Technology
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• v.35 no.4
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• pp.635-641
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• 2003

A non-thermal pasteurization technology, high Pulsed Electric Field (PEF) has been thought to be a new alternative processing technology instead of heating. The objective of this study was to examine and compare the effect of PEF and High Temperature Short Time (HTST) treatments on the physicochemical, microbiological and sensory characteristics of citrus juices. Total sugar and titratable acidity values of fresh citrus juice and two treatments were not significantly different each other at p<0.05. The concentration of vitamin C in fresh citrus juice $(31.2{\pm}0.59\;mg%)$ was not significantly different with the value of PEF treatment $(29.4{\pm}0.75\;mg%)$ but was significantly higher than the value of HTST treatment $(27.4{\pm}0.75\;mg%)$. The color values (L, a, and b) in PEF treatment were significantly lower than the fresh citrus juice, but were higher than the values of HTST treatment. Both total bacterial cell counts $(6.65\;{\pm}\;0.08\;log_{10}(cfu/mL))$ and yeast counts $(7.79{\pm}0.07\;log_{10}(cfu/mL))$ in fresh citrus juice were significantly reduced by PEF $(1.39{\pm}0.14,\;2.42{\pm}0.1\;log_{10}(cfu/mL))$ as well as HTST treatment (0, 0). PE activity of fresh citrus juice $(1.3{\pm}0.12\;units/mL)$ was significantly reduced by PEF treatment $(0.11{\pm}0.01\;units/mL)$ and was totally inactivated by HTST treatment. Sensory evaluation scores in flavor, taste and overall acceptability between the fresh and PEF treated citrus juices $(7.2{\sim}7.5)$ were not significantly different but the values of HTST treatment $(5.1{\sim}5.8)$ were lower than others. Consequently, PEF treatment is thought to be a good alternative pasteurization method for fresh citrus juice to HTST treatment due to its strong pasteurization effect, reduced destruction of nutrients and good sensory characteristics.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1529-1535
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• 1999

This study was done for the extraction of carotenoid from Phaffia rhodozyma in combination with PEF and other methods. PEF treatment conditions were $30{\sim}80\;kV/cm,\;100{\sim}1000\;Hz\;and\;100{\sim}1000\;{\mu}s$. In order to increase permeability of yeast cell wall, various methods such as freezing-thawing, mechanical treatment, solvents, permeabilizing agents, and yeast cell wall lytic enzyme were used before PEF treatment. The combination of PEF $(50\;kV/cm,\;300\;Hz,\;1000\;{\mu}s)$ and conventional methods such as solvent and freezing-thawing pre-treatment had no effects on the extraction of carotenoid pigments. The extent of extracted carotenoid by the PEF $treatment(50\;kV/cm,\;300\;Hz,\;1000\;{\mu}s)$ combined with yeast cell wall lytic enzyme and mechanical pre-treatment increased 52% and 69.8% more than the sum of that by each treatment, respectively. Permeabilizing agents, especially Tween 20 and capric acid, enhanced the extraction efficiency of carotenoid pigments from P. rhodozyma cells. These results indicated the feasibility for the continuous extracting carotenoid pigments from P. rhodozyma by PEF combined with other permeabilizing methods.