• Title/Summary/Keyword: 17-4 PH

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Some Properties of the Polyphenol Oxidase from Potatoes (Solanum tubersum L.) and Inhibiting Effect of the Polyphenol Oxidase by Sulfites (감자 Polyphenol Oxidase의 효소학적 성질 및 아황산염에 의한 활성억제 효과)

  • Ha, Young-Duk;Lee, Mi-Ock
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.17 no.3
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    • pp.198-204
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    • 1988
  • This study was aimed at obtaining elementary data on enzymatic browning of potato and potato products and examining the inhibitory method of browning. Therefore, we extracted polyphenol oxidase from potatoes(Solanum tubersum L.), and investigates its general properties and inhibiting effects of its activity with the different concentrations of sulfites($Na_2S_2O_4,\;Na_2SO_3{\cdot}7H_2O,\;NaHSO_3$). The optimum pH and temperature of polyphenol oxidase were observed to be 6.5 and $37^{\circ}C$ respectively. The polyphenol oxidase at PH5 was very stable, and the activity of polyphenol oxidase between pH $5.0{\sim}9.0$ was estimated to be relatively high, showing $72{\sim}75%$ of its activity at pH5. The polyphenol oxidase was very stable when heated at $40^{\circ}C$ for one hour, and almost 50% of enzyme activity was decreased when heated at $70^{\circ}C$ for twelve minutes. At 0.1mM concentrating of sulfites the relative activity of polyphenol oxidase was 98% in all the three cases of sulfites. Thus sulfites at 0.1mM concentration was found to have little inhibiting effect on polyphenol oxidase activity. At 1mM concentration of sulfites $NaHSO_3$ showed the lowest 36% relative activity among the three. At 5mM concentration of sulfites, the relative activity of $Na_2SO_3{\cdot}7H_2O$ was the lowest 14%.

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반응표면분석에 의한 쇠고기 야채 쌀죽의 이화학적 및 관능적 특성 변화

  • 이용욱;금준석;은종방
    • Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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    • 2003.10a
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    • pp.167.2-168
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    • 2003
  • 현대 사회는 서구적인 식생활의 변화로 인해 조리가 간편하고 조리 시간이 짧은 즉석식품과 영양 기호식품을 동시에 충족시켜주는 음식에 대한 소비가 늘고 있는 실정이다. 또한 최근 미곡의 공급량에 비해서 소비량이 해마다 감소하여 재고미의 증가를 볼 때, 쌀의 새로운 이용방법 모색이 절실히 요망된다. 따라서 쌀의 소비촉진과 현대사회의 소비형태를 접목시켜서 쇠고기와 야채를 이용한 즉석쌀죽을 개발하고자 하였다. 쇠고기, 야채 및 쌀가루를 이용한 soup mix의 최적 배합비를 설정하기 위하여 제조조건에 따라 다르게 제조한 쇠고기 야채 쌀죽의 이화학적 및 관능적 특성에 미치는 변화를 조사하였다. 이때 야채의 배합비에 따른 이화학적 및 관능적 특성을 모니터링 하고자 반응표면분석법 (response surface methodology, RSM)을 이용하였다. 요인변수(Xn)를 쌀의 양에 대한 버섯의 비율 (X$_1$), 당근의 비율 (X$_2$), 대파의 비율 (X$_3$)로 하여 중심합성계획에 따라 17실험구로 구분하여 조리실험을 실시하였고, 반응변수(Yn)는 soup mix를 이용하여 제조한 쇠고기 야채 쌀죽의 이화학적 특성인 색도의 L*값 (Y$_1$), a*값 (Y$_2$), b*값 (Y$_3$), 점도(Y$_4$), 퍼짐성 (Y$_{5}$), 고형분 함량(Y$_{6}$), PH (Y$_{7}$)으로 하였으며 관능적 특성인 색 (Y$_{8}$), 향 (Y$_{9}$), 점성 (Y$_{10}$), 맛 (Y$_{11}$), 전체적인 기호도 (Y$_{12}$)를 종속변수로 하여 회귀분석에 이용하였다. 회귀분석에 의한 모델식의 예측에는 SAS (statistical analysis system)program을 사용하였으며, 3차원 반응표면 분석법으로 해석하였다. 야채의 배합비에 따라 제조한 쇠고기 야채 쌀죽의 물리적 특성인 색도의 L*, a*, b* 값에 대한 반응표면 회귀식의 $R^2$은 각각 0.6098(p> 0.05), 0.8803 (p <0.05), 0.6781(p> 0.05)로서 b값에 있어서 그 유의성이 5%수준에서 인정되어 b값에 미치는 영향이 크다는 것을 알 수 있었다. L*값은 63-68사이로, a*값은 0.13에서 -0.89사이를 b*값은 2-5값 사이에서 변화하여 제조한 죽의 색이 옅은 황색임을 알 수 있었다. 고형분 함량, 퍼짐성과 pH에 대한 $R^2$은 각각 0.4280, 0.5433과 0.2406임을 볼 때 버섯, 당근, 대파의 비율에 따라 제조한 쇠고기 야채 쌀죽의 고형분 함량, 퍼짐성과 pH는 설정된 범위내에서 그 유의성이 인정되지 않아 큰 영향을 미치지 않음을 알 수 있었다. 관능검사 결과, 색과 향에 대한 반응표면 회귀식의 $R^2$은 각각0.6000과 0.7825이고 P-value는 각각 0.4290과 0.0942로서 5% 수준에서 유의한 상관성이 없음을 확인할 수 있었다. 맛과 점성에 대한 $R^2$은 0.8717과 0.8068이고 P-value는 각각 0.0195 (p <0.05)와 0.0612로서 야채의 배합비에 따라 맛에 있어서 유의확률 5%수준에서 그 유의성이 인정되었으며, 전체적인 기호도에 대한 유의성은 $R^2$이 0.8463이고 P-value는 0.0344 (p <0.05)임을 볼 때, 설정된 범위내에서 야채의 배합비에 따라 제조한 쇠고기 야채 쌀죽의 맛과 기호도에 큰 영향을 미치는 것을 알 수 있었다. 그리고 최대 임계점이 버섯의 첨가량은 0.99%, 당근의 첨가량은 0.97%, 대파의 첨가량은 0.59%에서 최적 반응표면을 나타내었다. 이상의 결과로 볼 때, 야채의 배합비에 따른 맛과 전체적인 기호도에 있어서 그 유의성이 5%수준에서 모두 유의한 상관관계를 보였으며, soup mix 제조시 쌀가루 양에 대한 야채의 최적 배합비는 버섯, 당근, 대파에 있어서 각각 0.99, 0.97과 0.59%임을 알 수 있었다.

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Contribution of Oswald Veblen to AMS and its meaning in Korea (Oswald Veblen이 미국수학계에 미친 영향과 한국에서의 의미)

  • Lee, Sang-Gu;Ham, Yoon-Mee
    • Journal for History of Mathematics
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    • v.22 no.2
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    • pp.27-52
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    • 2009
  • This article discusses the contributions of the leader Oswald Veblen, who was the president of AMS during 1923-1924. In 2006, Korea ranked 12th in SCIE publications in mathematics, more than doubling its publications in less than 10 years, a successful model for a country with relatively short history of modern mathematical research. Now there are 192 four-year universities in Korea. Some 42 of these universities have Ph.D. granting graduate programs in mathematics and/or mathematical education in Korea. Rapid growth is observed over a broad spectrum including a phenomenal performance surge in International Mathematical Olympiad. Western mathematics was first introduced in Korea in the 17th century, but real significant mathematical contributions by Korean mathematicians in modern mathematics were not much known yet to the world. Surprisingly there is no Korean mathematician who could be found in MaC Tutor History Birthplace Map. We are at the time, to have a clear vision and leadership for the 21st century. Even with the above achievement, Korean mathematical community has had obstacles in funding. Many people thinks that mathematical research can be done without funding rather unlike other science subjects, even though they agree fundamental mathematical research is very important. We found that the experience of early American mathematical community can help us to give a vision and role model for Korean mathematical community. When we read the AMS Notice article 'The Vision, Insight, and Influence of Oswald Veblen' by Steve Batterson, it answers many of our questions on the development of American mathematics in early 20th century. We would like to share the story and analyze its meaning for the development of Korean Mathematics of 21st century.

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Soil Classification of Paddy Soils by Soil Taxonomy (미국신분류법(美國新分類法)에 의(依)한 답토양의 분류(分類)에 관한 연구)

  • Joo, Yeong-Hee;Shin, Yong-Hwa
    • Korean Journal of Soil Science and Fertilizer
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    • v.11 no.2
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    • pp.97-104
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    • 1979
  • According to Soil Taxonomy which has been developed over the past 20 years in the soil conservation service of the U. S. D. A, Soils in Korea are classified. This system is well suited for the classification of the most of soils. But paddy field soils have some difficulties in classification because Soil Taxonomy states no proposals have yet been developed for classifying artificially irrigated soils. This paper discusses some problems in the application of Taxonomy and suggestes the classification of paddy field soils in Korea. Following is the summary of the paper. 1. Anthro aquic, Aquic Udipsamments : The top soils of these soils are saturated with irrigated water at some time of year and have mottles of low chroma(2 or less) more than 50cm of the soil surface. (Ex. Sadu, Geumcheon series) 2. Anthroaquic Udipsamments : These sails are like Anthroaquic, Aquic Udipsamments except for the mottles of low chroma within 50cm of the soil surface. (Ex. Baegsu series) 3. Halic Psammaquents : These soils contain enough salts as distributed in the profile that they interfere with the growth of most crop plants and located on the coastal dunes. The water table fluctuates with the tides. (Ex. Nagcheon series) 4. Anthroaquic, Aquic Udifluvents : They have some mottles that have chroma of 2 or less in more than 50cm of the surface. The upper horizon is saturated with irrigated water at sometime. (Ex. Maryeong series) 5. Anthro aquic Udifluvents : These soils are saturated with irrigated water at some time of year and have mottles of low chroma(2 or less) within 50cm of the surface soils. (Ex. Haenggog series) 6. Fluventic Haplaquepts : These soils have a content of organic carbon that decreases irregularly with depth and do not have an argillic horizon in any part of the pedon. Since ground water occur on the surface or near the surface, they are dominantly gray soils in a thick mineral regolith. (Ex Baeggu, Hagseong series) 7. Fluventic Thapto-Histic Haplaquepts : These soils have a buried organic matter layer and the upper boundary is within 1m of the surface. Other properties are same as Fluventic Haplaquepts. (Ex. Gongdeog, Seotan series) 8. Fluventic Aeric Haplaquepts : These soils have a horizon that has chroma too high for Fluventic Haplaquepts. The higher chroma is thought to indicate either a shorter period of saturation of the whole soils with water or some what deeper ground water than in the Fluventic Haplaquepts. The correlation of color with soil drainage classes is imperfect. (Ex. Mangyeong, Jeonbug series) 9. Fluventic Thapto-Histic Aeric Haplaquepts : These soils are similar to Fluventic Thapto Histic Haplaquepts except for the deeper ground water. (Ex. Bongnam series) 10. Fluventic Aeric Sulfic Haplaquepts : These soils are similar to Fluventic Aeric Haplaquepts except for the yellow mottles and low pH (<4.0) in some part between 50 and 150cm of the surface. (Ex. Deunggu series) 11. Fluventic Sulfaquepts : These soils are extremely acid and toxic to most plant. Their horizons are mostly dark gray and have yellow mottles of iron sulfate with in 50cm of the soil surface. They occur mainly in coastal marshes near the mouth of rivers. (Ex. Bongrim, Haecheog series) 12. Fluventic Aeric Sulfaquepts : They have a horizon that has chroma too high for Fluventic Sulfaquepts. Other properties are same as Fluventic Sulfaquepts. (Ex. Gimhae series) 13. Anthroaquic Fluvaquentic Eutrochrepts : These soils have mottles of low chroma in more than 50cm of the surface due to irrigated water. The base saturation is 60 percent or more in some subhroizon that is between depth of 25 and 75cm below the surface. (Ex. Jangyu, Chilgog series) 14. Anthroaquic Dystric Fluventic Eutrochrepts : These soils are similar to Anthroaquic Fluvaquentic Eutrochrepts except for the low chroma within 50cm of the surface. (Ex. Weolgog, Gyeongsan series) 15. Anthroaquic Fluventic Dystrochrepts : These soils have mottles that have chroma of 2 or less within 50cm of the soil surface due to artificial irrigation. They have lower base saturation (<60 percert) in all subhorizons between depths of 25 and 75cm below the soil surface. (Ex. Gocheon, Bigog series) 16. Anthro aquic Eutrandepts : These soils are similar to Anthroaquic Dystric Fluventic Eutrochrepts except for lower bulk density in the horizon. (Ex. Daejeong series) 17. Anthroaquic Hapludalfs : These soils' have a surface that is saturated with irrigated water at some time and have chroma of 2 or less in the matrix and higher chroma of mottles within 50cm of the surface. (Ex. Hwadong, Yongsu series) 18. Anthro aquic, Aquic Hapludalfs : These soils are similar to Anthro aquic Hapludalfs except for the matrix that has chroma 2 or less and higher chroma of mottles in more than 50cm of the surface. (Ex. Geugrag, Deogpyeong se ries)

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