• Food Science of Animal Resources
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• v.29 no.6
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• pp.736-742
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• 2009

This study was conducted to investigate the effect of various high pressure freezing and thawing treatments on the physical properties of pork. To compare the effects of the freezing and thawing process on meat quality, atmospheric freezing followed by running water thawing (AFRT), pressure shift freezing followed by running water thawing (SFRT), and pressure shift freezing and pressure assisted thawing (SFAT) were conducted at pressure of 250 MPa and cooling temperature of $-22^{\circ}C$. SAFT and SFRT showed a shorter phase transition time and total thawing time than AFRT. The pH value of treated samples increased significantly (p<0.05) compared to unfrozen meat. In addition, SFAT and SFRT showed a higher pHvalue than AFRT. Although the water holding capacity was significantly decreased (p<0.05) for SFAT and SFRT, SFRT reduced drip loss. In regards to color, SFAT and SFRT resulted in a significant increase in color parameters (p<0.05) relative to AFRT, while SFAT produced a higher L*-value. High pressure treatment significantly increased shear force (p<0.05) compared to AFRT, and, where SFRT showed the highest shear force. Therefore, these combined results indicated that the hydrostatic pressure treatment improved the functional properties of pork and increased the freezing and thawing rate.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.598-603
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• 2000

This study was conducted to enhance the storage stability and the wholesomeness of salted and fermented shrimp manufactured with different salt levels by high hydrostatic pressure sterilization. The effects of high hydrostatic pressure treatment on the putrefactive bacteria in the fermented shrimps were investigated and the sterilization kinetics was analyzed. The initial microbial counts of the fermented shrimp with 8%, 18% salt aged for 6 weeks at $20^{circ}C$ were $1.6{\times}10^3,\;1.4{\times}10^4$ CFU/g for bacteria grown on Vibrio selective media, $9.3{\times}10^3,\;1.7{\times}10^5$ CFU/g for bacteria grown on Staphylococcus selective media, respectively, and null for bacteria grown on Salmonella selective media. The degree of the sterilization increased with the magnitude of the pressure and the treatment time. The fermented shrimp pressurized at 6,500 atm for 10 min had no detectable bacteria grown on Vibrio and Staphylococcus selective media at $10^2$ CFU/g detecting limit. High hydrostatic pressure sterilization could be analyzed by first order reaction kinetics. The $D_P$ values of the bacteria grown on Vibrio selective media of the fermented shrimp at 18% salt were higher than those at 8% salt, while those of the bacteria grown on Staphylococcus selective media showed an inverse trend. The $z_p$ values of 8% salt fermented shrimp were higher than those of 18% salt for both bacteria grown on Vibrio selective media and Staphylococcus selective media. High hydrostatic pressure treatment could be applied for the sterilization of the fermented shrimp, and the optimum high pressure sterilization condition was 10 min treatment at 6,500 atm.

• Food Science and Preservation
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• v.22 no.5
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• pp.714-720
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• 2015

Biji is a tofu by-product made by squeezing the liquid out of the dregs left over from making tofu. The objectives of this research were to break the biji into sub-micron-scale particles and to prepare a biji sub-micron suspension having increased quality characteristics such as antioxidant capacity, polyphenol, dietary fiber, and soluble protein contents, in comparison with untreated biji. Disruption of biji by an ultra-high-pressure homogenization (UHPH) process was used to prepare the sub-micron suspension of biji. UHPH can be used to prepare emulsions or suspensions with extremely small particle sizes. The effect of the UHPH process on biji was studied at 1,000, 1,500, and 2,000 bar. The extraction yield increased up to 1.64 times by breaking the biji to form a sub-micron suspension. The soluble dietary fiber, protein, and free amino acid contents were increased by the UHPH process (p<0.05), in comparison with those of untreated biji. Furthermore, the total sugar, free sugar, and total polyphenol contents of biji were augmented by the UHPH process. Antioxidant activity (ABTS) after exposure to UHPH (1,000-2,000 bar) was well retained (p<0.05). The extraction efficiencies and nutritive components were enhanced by increasing the pressure in the UHPH process.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.10
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• pp.1619-1626
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• 2014

This study was conducted to evaluate the effects of Joule heating and hydrostatic pressure on reduction of total aerobes and spores of Bacillus cereus in four kinds of sauces prepared with traditional Korean fermented foods. Total aerobes and inoculated spores of B. cereus in sauces were assayed after treatment or during storage at $30^{\circ}C$ after 4 or 8 weeks. Joule heating ($85^{\circ}C$), hydrostatic pressure (550 Mpa, 5 min), and antimicrobial additive (3% ethanol) were separately applied or combined as a hurdle technique. A 1.0~2.0 log reduction in total aerobes of Doenjang and Gochujang sauce was observed upon Joule heating at 80, 85, and $95^{\circ}C$. Significant reductions (0.92~1.21 log/0.5~1.38 log and 1.26~1.7 log/0.47~3.45 log) of total aerobes/spores of B. cereus in Doenjang and Gochujang sauce, respectively, occurred upon JA (Joule+additive), JP (Joule+hydrostatic pressure) or JAP (Joule+additive+ hydrostatic pressure). Effects of each treatments were maintained or increased during storage for 8 weeks at $30^{\circ}C$, suggesting that total aerobes and spores of B. cereus in Doenjang and Gochujang sauce can be controlled through Joule heating or hydrostatic pressure treatment.

• Korean Journal of Food Science and Technology
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• v.32 no.2
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• pp.373-379
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• 2000

Low salt fermented anchovy was stored at $25^{\circ}C$ for a period of 20 days from the time of ultra-high pressure treatment under different operating conditions, such as magnitude of pressure($(200{\sim}500\;MPa)$, temperature$(20{\sim}50^{\circ}C)$ and treatment time$(5{\sim}20\;min)$ with viable cell count(VCC) and quality assessments conducted at regular intervals. VCC decreased logarithmically during storage. Lower values of VCC in the treated samples were observed compared to the untreated. A gradual increase in peroxide value was noticed during storage, compared to those of the untreated which showed a sudden rise. Thiobarbituric acid value decreased initially and remained at that level before rising almost exponentially between 12 and 20 days. Volatile basic nitrogen increased gradually during storage. Amino nitrogen remained almost constant up to 20 days, regardless of any conditions investigated. High pressure treatment maintained better quality during storage at $25^{\circ}C$ by reducing the viable cell count in low salt fermented anchovy.

• Food Science of Animal Resources
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• v.26 no.4
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• pp.464-470
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• 2006

This study was carried out to investigate the effect of various high pressure freezing treatments on the physical properties of pork To compare the effect of freezing on meat quality, atmospheric freezing (AF), pressure and freezing (PF), pressure shift freezing (USF) and pressure assisted freezing (PAF) were conducted at pressure of 100 MPa. Water binding properties, shear force and colour were measured as physical properties of pork PAF showed shorter phase transition time than PSF. Although significant increase (p<0.05) in water binding properties was found only at PAF, meat frozen under hydrostatic pressure environment showed improved water binding properties. However, all high pressure freezing treatment caused significantly increased shear force (p<0.05), especially at PF treatment. In color, all high pressure freezing treatments showed significantly higher color parameters (p<0.05) than AF, whilst no significant differences among high pressure freezing treatments were found (p>0.05). Therefore the result indicated that applied hydrostatic pressure improved functional properties of pork with increasing freezing rate and PAF had more potential benefit than PSF at mild pressure range.

• Korean Journal of Food Science and Technology
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• v.33 no.2
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• pp.226-230
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• 2001

High hydrostatic pressure was applied to Foxtail Millet Takju to investigate the effects of high pressure on inactivation of microorganisms and enzymes. Total bacteria, lactic acid bacteria and yeast in untreated Takju were $6.8{\times}10^7,\;1.3{\times}10^8\;and\;8.4{\times}10^7\;CFU/mL$, respectively. Total bacterial count in Takju reduced to $2.2{\times}10^5\;CFU/mL$, while lactic acid bacteria and yeast were sterilized completely when heated at $65^{\circ}C$ for 30 min. Lactic acid bacteria and yeast decreased with the increase of treatment pressure, and pressurization of 400 MPa for 10 min at room temperature sterilized completely the lactic acid bacteria and yeast in Takju. Total bacteria were not sterilized with pressurization of even 600 MPa at room temperature. Total bacteria were completely sterilized at $66^{\circ}C/400\;MPa/60\;min\;and\;66^{\circ}C/600\;MPa/10\;min$. Pressurization of Takju caused a partial inactivation of ${\alpha}-amylase$, and after pressurization at 600 MPa for 10 min at room temperature, 73.2% of the original activity remained. The activity of glucoamylase increased with the increase of treatment pressure. Treatment at $66^{\circ}C/400\;MPa/10\;min$ reduced the activity of ${\alpha}-amylase$ by 59.7% and glucoamylase by 20.5%. ${\alpha}-Amylase$ was inactivated to less than 1.2% of the original activity at $66^{\circ}C/600\;MPa/30\;min$.

• Korean Journal of Food Science and Technology
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• v.33 no.4
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• pp.444-450
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• 2001

Kochujang, fermented hot pepper paste, was treated with combined high hydrostatic pressure and heat. Viable cell counts and chemical compositions of Kochujang were determined as a function of high pressure processing conditions such as temperature, pressure and time, and during storage for 120 days at $37^{\circ}C$. Viable cell counts were decreased with the increase of temperature, pressure and time. Viable cell counts in the treated Kochujang were decreased up to $0{\sim}3$ log cycle with the temperature of $49{\sim}73^{\circ}C$, $0{\sim}3$ log cycle with the pressure of $380{\sim}680\;MPa$, and $2{\sim}5$ log cycle with the time of $10{\sim}70\;min$, compared with the untreated. pH, titratable acidity, amino nitrogen, reducing sugar and ethanol content in the treated Kochujang were comparable to the untreated regardless of the treatment condition. Hunter L, a and b values in the treated Kochujang were higher than those of the untreated. Viable cell counts were decreased with the increase of the storage period at $37^{\circ}C$. Viable cell counts in Kochujang treated at 380 MPa/30 min were decreased up to 2 log cycle from $1.8{\times}10^6\;to\;1.94{\times}10^4\;CFU/g$ after 120 days of storage, while those at 680 MPa/70 min were not detected after 60 days from the initial stage of $4.00{\times}10^1\;CFU/g$. pH, amino nitrogen and ethanol content were decreased, and titratable acidity were increased significantly as the increase of the storage period. Hunter L, a and b values also decreased significantly. The changes in physicochemical properties of Kochujang treated at 680 MPa/70 min were greater than those at 380 MPa/30 min.

• Food Industry And Nutrition
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• v.10 no.3
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• pp.30-36
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• 2005

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.272-279
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• 2018

The high pressure processing (HPP) is a technology which can preserve the quality of foods, such as the fresh taste, incense, texture, vitamin content, and so on, by minimizing the heating process. It does so by applying an instantaneous and uniform pressure that is the same as the water pressure that is 60 km deep in the sea. HPP is a technology that can inhibit food poisoning and spoilage caused by microorganisms and is currently an actively studied area. In this study, we investigated the effects of a high pressure treatment (0, 4, 6 min) on sliced ham, which is a typical meat product, at 600 MP a were tested for their effect on freshness. Moisture contents varied from 48 to 69%, salinity varied from 1.07 to 1.11%, and the pH decreased from 6.4~6.5 to 6.1~5.15. However, there was no difference between the control and treatment groups. General bacteria stored at $20^{\circ}C$ after hyper-pressure treatment were found to have no significant microorganisms in all groups until 4 weeks. but exceeded $10^5$ in control group and HPP 6 min treatment group from 5 weeks, At week 7, it was found to exceed $10^6$. The results indicate it was not possible to ingest food in the 4-and 6 minute treatment groups. Coliform was not observed in all groups despite observing for a total of 7 weeks at $20^{\circ}C$ weight test. VBN, a method used to determine the protein freshness of meat, showed a VBN value of less than 1 mg% until the fourth week and a value of 1 to 2 mg% after 5 weeks. The TBA was used as an index of the degree of fat acidosis in the meat tissues. The results showed it was below 0.18 mgMA / kg until the end of 7 weeks; this value was within the range for fresh meat, and there was no difference in treatment group. In this experiment, deformation of the packaging material did not occur and no swelling occurred due to the generation of gas. It is believed that the basic preservation effect was achieved only by blocking with the air due to the close contact of the packaging material.