• Journal of Food Hygiene and Safety
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• v.34 no.1
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• pp.106-114
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• 2019

The effect of physical and chemical treatments to reduce staphylococcal phages was investigated. To determine impact of physical treatment on viability of phages, two staphylococcal phages (SAP84 and SAP89) were treated with multiple heat ($55^{\circ}C$ and $60^{\circ}C$) and pH (pH4, 7, 10) conditions. Viability of SAP 84 was dramatically reduced at 60C and SAP 89 was completely inactivated at 60C within 25 min. Overall, the two phages were stable under all the pH conditions tested except for the SAP 89 at pH 10. Treatments, a 10% FAS (Ferrous Ammonium Sulfate) solution and various density of ethanol and sodium hypochlorite were used to reduce the two phages. SAP 84 was unstable in 50% and 70% ethanol. However, SAP 84 and SAP 89 showed high tolerance after exposure to 100 ppm of sodium hypochlorite which is known as an effective sterilizer. As soon as the two phages were treated with 10% FAS, which is used as a virucidal agent, they were inactivated and did not form any plaque. The result of this study provides additional evidence that staphylococcal phages can be controlled by various physicochemical treatments.

• Korean Journal of Food Science and Technology
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• v.40 no.4
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• pp.365-374
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• 2008

Plastics are comparatively new polymeric materials that are manufactured by chemical synthesis, making them different from natural materials such as wood, paper, stone, metal, and glass. Due to a wide range of properties, including processing capabilities and duration, plastics have become rapidly ubiquitous, being used in all industries, and have improved our quality of life. However, it is true that plastics cause environmental contamination problems that have become important social issues, such as environmental hormone leakage due to incineration or reclamation, difficulty in securing reclamation sites, and deadly poisonous dioxin generated by the incomplete incineration of waste plastic materials. To solve these problems, it is urgent to develop and commercialize degradable plastics that can be stably and conveniently used just as general plastics, and that are easily decomposed by sunlight, soil microbes, and heat generated from reclaimed land after use. This review presents recent worldwide trends in the development and marketing of environmentally degradable plastics.

• Food Science and Preservation
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• v.11 no.3
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• pp.319-324
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• 2004

The antimicrobial activity of the extract of citrus peel prepared by the method of hot water, ethanol and sugar was examined. The results showed that the extract of citrus peel prepared by hot water or ethanol did not have antimicrobial activity, but the extract by 10$\%$(w/v) sugar revealed the high antimicrobial activity. Extracted in 10%(w/v) sugar solution for 9 days, showed the highest antimicrobial activity against 8 strains of bacteria. The minimum inhibition concentration was found to be 0.5$\%$(v/v) against S. aureus, 1.5$\%$(v/v) against B. subtilis, M. luteus and E. coli, and 2.0$\%$(v/v) against S. mutans. The antimicrobial activity of the citrus peel extract was stable regardless of the treatment at 40 $\~$ 100 $^{\circ}C$C for 20 min and unstable response to the change of pH. The results suggested the development of citrus peel as heat-stable antimicrobial agents.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.4
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• pp.687-694
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• 1996

Myrosinase was purified from Korean mustard seed(Brassica juncea) by a sequential process of DEAE-cellulose, concanavalin A-sepharose, and Superose 6 chromatography. The molecular weight of puri-fied myrosinase(II-2) determined by SDS-polyacrylamide electrophoresis was 67KD. About a 248-fold purification for myrosinase II-2 was obtained after Superose 6 chromatography. Optimum pH of the myrosinase was 7.0 and optimum temperature of the enzyme was $3^{\circ}C.$ The enzyme was stable at pH 7.0, and below $30^{\circ}C.$ Cu, Hg and Fe ion significantly inhibited the enzyme activity, but ascorbic acid enhanced, resulting in a maximum activity by 1mM ascorbic acid. Among tile ascorbic acid ana-logues, dehydroascorbic acid inhibited the enzyme activity, whereas others showed a little effect. Reducing agents such as 2-mercaptoethanol and dithiothreitol inhibited the enzyme activity, but the reducing agents with ascorbic acid was enhanced enzyme activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.1
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• pp.83-91
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• 2017

This study made jelly by adding Sansuyu (Corni Fructus) puree and examined the types and contents of gelling agents as well as the physicochemical characteristics of jelly depending on heating time. Water content of Sansuyu puree was 89.39%, pH was 2.92, sugar content was $10.28^{\circ}Brix$, and total polyphenol content was 1,791.71 mg GAE/100 g. As the added amount of Sansuyu puree increased, pH decreased slightly from 3.04 to 2.97, and yield stress decreased greatly. As heating time increased, red color was unstable and changed to yellow. When heated more than 5 min, jelly was not formed. The level of preference for jelly consisting of 10% Sansuyu puree, 1.5% agar, and 1.0% carrageenan was the highest at 5.15. Using pulp of Sansuyu, it will be possible to make jelly consisting of various bioactive substances.

• Korean Journal of Food Science and Technology
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• v.25 no.4
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• pp.404-406
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• 1993

In order to detect the gelation of ultrahigh temperature (UHT) treated market milks during storage at 20+1C, the free amino groups were quantified with 2,4,6-trinitrobenzene sulfonic acid, and the measurement of pH values and the alcohol test were monthly carried out. The average tree amino groups were $0.94{\sim}1.11{\mu}M$ at 1 month, $1.95{\sim}2.17{\mu}M\;at\;5{\sim}6$ month and $4.95{\sim}6.36{\mu}M$ at 12 month. The pH values at the same time as above were $6.72,\;6.49{\sim}6.55\;and\;6.14{\sim}6.16$, respectively. The alcohol test showed positive results at $5{\sim}6$ month, which could indicate the casein instability and beginning of gelation. These results suggest that the gelation of UHT market milks could he predicted through checking some chemical parameters weekly and be helpful for quality control.

• Korean Journal of Food Science and Technology
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• v.27 no.2
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• pp.170-175
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• 1995

Physical and physiological properties of isomaltooligosaccaride (IMO), fructooligosaccharide (FO) and sucrose were investigated. The viscosity and moisture retention power of IMO were similar to those of FO. IMO had an excellent heat and pH stability compared with FO and sucrose. To investigate the effect of oligosaccharides on the growth of mice, each sample was administered orally to mice for 2 weeks. Weight change, moisture content of feces, weight of appendix and the ratio of Bifidobacterium to total microorganisms in the feces were examined. There were no significant differences in the weight increases and the efficiency of feeds. Moisture content of feces was highest in the IMO feeding group, and IMO promoted selectively the growth of Bifidobacterium. On the other hand, FO group showed bigger cecum than other groups.

• Korean Journal of Food Science and Technology
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• v.17 no.4
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• pp.265-270
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• 1985

The saponin yield and its compositional changes of red ginseng extract (RG-EXT) was investigated during extraction at various temperature for 5 times of 8 hours. The higher temperature resulted an increase in solids yield while the total saponin recovered was decreased, particularly at $100^{\circ}C$. A relatively lower thermal stability was found for protopanaxadiol saponin, one of the saponin fractions, than protopanaxatriol saponin. The compositional ratio of saponin at ginsenoside level was little affected by extraction time. The yields data showed that more than 94% of total saponin was recovered by 3$\sim$4 times of 8 hours extraction. Extraction at $80^{\circ}C$ for 4 times of 8 hours were suggested for preparation of RG-EXT from the result of this work.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.235-239
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• 1973

Studies were made on the sugars composition in dried lavers (Porphyra yezoensis Ueda) and changes in the contents of sugars during the storage under a dry and a humid conditions respectively. 1) No notable difference was observed in the glucose content between those dried lavers samples, which were stored under dry and humid conditions. Galactose content showed little change under a dry condition, but under a humid condition rapidly increased to a maximum of about ten times of its initial amount and then decreased gradually. 2) The content of floridoside rapidly decreased under a humid condition while slowly decreased under a dry condition, of which tendency is a contrast to that of galactose. 3) One of the unidentified components, which is deduced to be isofloridoside, showed a fluctuation pattern, which bears resemblance to that of floridoside.

• Korean Journal of Food Science and Technology
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• v.46 no.6
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• pp.677-681
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• 2014

The effects of toasting, simulated gimgui (dried and toasted laver) manufacturing, on lipid oxidation and antioxidant and pigment contents of dried laver (Porphyra spp.) were evaluated by peroxide value (POV) and conjugated dienoic acid (CDA) value measurement, HPLC, and spectrophotometry. Dried laver was toasted for 40 or 300 s at $120^{\circ}C$, or for 2 or 5 s at $250^{\circ}C$. The POV and CDA contents were significantly higher in the toasted samples (0.60-0.69 mmol/kg and 2.17-4.20%, respectively) except in samples toasted at $120^{\circ}C$ for 40 s, compared to those in the non-toasted samples (0.43 mmol/kg and 1.21%, respectively). Chlorophyll was the most stable pigment during toasting (>90% retention), followed by carotenoids (50-77% retention) and phycocyanins and phycoerythrins (13-73% retention). Porphyran was the most stable antioxidant (>95% retention), and polyphenols, the most unstable antioxidant (24-75% retention). Despite the degradation of pigments and antioxidants during toasting, the dried laver still contained health-benefiting components after toasting.