• Title/Summary/Keyword: Physicochemical changes

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A Study on Physicochemical Properties of Artificial Substrates and Changes of Plant Growth in Tropical Plant Resources Research Center of Korea National Arboretum (국립수목원 열대온실 내 인공배합토의 물리화학적 특성 및 식물 생육 변화에 관한 연구)

  • Song, Jeong-Hwa;Jin, Hye-Young;Ahn, Tai-Hyeon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.13 no.2
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    • pp.52-62
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    • 2010
  • This study was carried out in the Tropical Plant Resources Research Center of Korea National Arboretum to determine the optimum edaphic environment for the growth of tropical and subtropical plants. The physicochemical properties of artificial substrates and the growth characteristics of tropical and subtropical plants were investigated. Subtropical plants exhibited a high growth rate when cultivated in a substrate of Dry Zone that had physical properties similar to those of arid native soil. Mediterranean plants showed a low growth rate when grown in a substrate of Subtropical Zone that required changes in acidity. The substrate of Tropical Zone had high organic matter and mineral contents and therefore had good physical properties:this substrate has a good environment for the stimulation of the growth of tropical plants. Our results indicate that the chemical properties such as pH and mineral contents of most artificial substrates need to be more urgently improved than their physical properties in order to ensure better growth of tropical and subtropical plants. Initial management strategies for the construction of new tropical greenhouses were formulated, and data from monitoring studies will be continuously gathered and incorporated in the manual to keep it updated.

Changes in the Physicochemical Characteristics and the Antioxidative Activity of Cheonggukjang by Addition of Walnut (호두 첨가에 따른 청국장의 이화학적 특성 및 항산화능 변화)

  • Park, Hwa-Young;Ryu, Beom-Seok;Choi, Ung-Kyu
    • The Korean Journal of Food And Nutrition
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    • v.28 no.6
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    • pp.1004-1010
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    • 2015
  • This study was conducted to investigate the changes in the physicochemical characteristics and antioxidant activity of cheonggukjang with the addition of walnuts. The pH of cheonggukjang did not change significantly with the addition of walnut. But the water content decreased significantly. Walnut addition to the soybean was expected to have a positive effect because the number of Bacillus subtilis was not reduced. The viscous substance content was significantly decreased when more than 20% of walnut was added to cheonggukjang. The addition of walnut made the color darker. The flavonoid and polyphenol content was sharply increased in proportion to the walnut addition and the DPPH radical scavenging activity of cheonggukjang also increased. Altogether, it was found that the addition of walnut had a positive influence on the cheonggukjang by increasing the antioxidant activity.

Changes in Physicochemical Properties of Baik-kimchi during Fermentation (백김치 숙성중 물리화학적 특성변화)

  • 문수경;류홍수
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.26 no.6
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    • pp.1013-1020
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    • 1997
  • To elicit the effect of fermentation on food quality of the watery Chinese cabbage pickles without fish sauce and red pepper paste(Baik-kimchi), changes in physicochemical properties and microstructure of fiber components were studied. Better water holding capacity(WHC) was showed in Baik-kimchi fermented at $25^{\circ}C$ than that of Baik-kimchi fermented at 5$^{\circ}C$. WHC measured at pH 2 and 6 were ranged from 10.18 to 16.79g/g dried sample for Baik-kimchi fermented at $25^{\circ}C$ and 6.51~14.58g/g dried sample for sample for samples at 5$^{\circ}C$, respectively. The higher WHC was resulted in pH controlled freeze-dried sample to pH 6 than that measured in pH 2 sample. The settling volume(SV) and oil adsorption capacity(OAC) increased with fermentation period and kept the same value for a little while, but slightly decreased in the over ripening period. Baik-kimchi fermented at $25^{\circ}C$ exhibited more shrunk microstructure of parenchyma cell and xylem than those of Baik-kimchi fermented at 5$^{\circ}C$. The appearance of SDF of the both Baik-kimchi ripened at 5$^{\circ}C$ and $25^{\circ}C$ could give granular shape, whereas the overripened Baik-kimchi had smooth surface of SDF. On the other hand, the IDF retained the original shape during fermentation.

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Changes of Physicochemical and Flavor Components of Ume According to Varieties and Picking Date (매실 품종과 수확 시기에 따른 이화학적 특성과 향기성분의 변화)

  • Song, Bo-Hyeon;Choe, Gap-Seong;Kim, Yong-Du
    • Food Science and Preservation
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    • v.4 no.1
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    • pp.77-85
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    • 1997
  • This study aims to determine the optimal picking time and the favorate variety for Ume processing. The changes of physicochemical components and flavors of 6 varieties of the Ume were investigated during maturing. Average weight of the fruit increased to the range of 151-292% from 70 days to 90 days after blooming. The hardness of fruit decreased during maturing and Koume variety was not suitable for processing among the last harvesting samples. Moisture and ash were reached to 89-91%, 0.57-0.69%, respectively, and the ash content increased during maturing. Among the Ume varieties, relatively high content of total acid was observed in Oshuku and Koume. The major organic acid were malic, citric, succinic, and tartaric acid. The content of malic acid decreased significantly, whereas citric acid increased during maturing. Thirty five kinds of flavor components were identified from the Ume fruit and main components were ethyl acetate, butyl acetate, and organic acid derivatives. Koume contained a large amount of flavor components among the Ume and the content increased during maturing.

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Changes in Physicochemical, Microbiological and Sensory Quality Characteristics of Ssamjang containing Cheongkukjang during Storage (청국장 첨가 쌈장의 저장 중 이화학적·미생물학적 및 관능적 품질특성 변화)

  • Yum, Eun Ji;Bang, Seon Ok;Kim, Kum-Suk
    • Journal of the East Asian Society of Dietary Life
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    • v.25 no.3
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    • pp.484-491
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    • 2015
  • This study investigated the quality variation characteristics of Ssamjang containing Cheongkukjang, in order to improve the degree of preference of Cheongkukjang. The amount of Cheongkukjang was set at 1% based on sensory evaluation. Ssamjang containing Cheongkukjang was stored at $37^{\circ}C$ for 13 weeks, after which quality variation characteristics were weekly. During storage for 13 weeks, physicochemical quality characteristics, moisture content, and pH of Ssamjang containing Cheongkukjang slightly decreased, whereas salt content did not change. Amino nitrogen content slightly increased by 1 week but decreased by 3 weeks and then increased by 5 weeks. For microbiology quality characteristics, viable cell counts and total cell counts of B. cereus were unchanged. For sensory quality characteristics, shape quality was poor after 13 weeks while mold, drying phenomenon, and swelling phenomenon were not observed. Therefore, physicochemical quality and microbiology quality of Ssamjang containing Cheongkukjang were unchanged during storage for 13 weeks, and the storage limit was determined to be 12 weeks according to sensory quality evaluation.

Effect of Different Cooking Methods and Temperatures on Physicochemical and Sensory Properties of Pork Hams: Ocoo, Sous-Vide, steaming, and boiling (조리 온도와 조리 방법에 따른 돼지고기 뒷다리살의 물리 화학적 및 관능적 품질차이 비교연구)

  • Jeon, Min-Sun;Shim, Je-Won;Yoon, Sun
    • Korean journal of food and cookery science
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    • v.29 no.3
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    • pp.309-316
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    • 2013
  • Quality changes of cooked meat products are dependent upon cooking temperature and heating methods. Pork ham is the most preferred pork dish using pork hams in South Korea although it is not suited to various cooking methods because its low fat content does not provide desirable physiochemical and sensory properties to consumers. Therefore, the objective of this study was to evaluate the effect of four different cooking methods on pork legs by comparing Ocoo, Sous-vide, steaming, and boiling technique at $80^{\circ}C$ and $100^{\circ}C$. Ultimately, the most effective cooking method and temperature to improve the quality of cooked pork hams was investigated. As the results of texture analysis, the samples cooked using Ocoo and Sous-vide methods showed higher springiness and cohesiveness than those using steaming and boiling methods. For the sensory evaluation, participants liked the hardness, juiciness, chewiness, tenderness of the samples using the OC method, resulting in the highest overall acceptance rate. The results of this study showed that using Ocoo or Sous-Vide cooking methods can improve the quality of cooked pork hams in both physicochemical and sensory properties.

ACE-inhibitory Effect and Physicochemical Characteristics of Yogurt Beverage Fortified with Whey Protein Hydrolysates

  • Lim, Sung-Min;Lee, Na-Kyoung;Park, Keun-Kyu;Yoon, Yoh-Chang;Paik, Hyun-Dong
    • Food Science of Animal Resources
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    • v.31 no.6
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    • pp.886-892
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    • 2011
  • This study investigated the ACE-inhibitory effect of yogurt beverage fortified with hydrolysates as well as the suitability of hydrolysates as a nutraceutical additive to yogurt beverage. Three whey protein hydrolysates hydrolyzed by alcalase, protamex, and trypsin were each added to yogurt beverage at concentrations of 1.25, 2.5, and 5 mg/mL. Yogurt beverage fortified with 2.5 mg/mL of hydrolysates had 61-69% ACE-inhibitory activity, whereas yogurt beverage fortified with 5 mg/mL of hydrolysates showed 74% ACE-inhibitory activity. There were no significant differences in ACE-inhibitory activity between the alcalase or protamex hydrolysates during storage; however, trypsin hydrolysate exhibited significant differences. On the other hand, physicochemical characteristics such as pH (3.47-3.77), titratable acidity (0.81-0.84%), colority, viable cell count, and sensory qualities were not significantly different among the tested yogurt beverage samples during storage. These results showed that yogurt beverage fortified with whey protein hydrolysates maintained antihypertensive activity and underwent no unfavorable changes in physicochemical characteristics regardless of enzyme type.

Changes in Physicochemical Properties of Rice Starch Processed by Ultra-Fine Pulverization

  • Han, Myung-Ryun;Chang, Moon-Jeong;Kim, Myung-Hwan
    • Journal of Applied Biological Chemistry
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    • v.50 no.4
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    • pp.234-238
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    • 2007
  • The effects of ultra-fine pulverization on the physicochemical properties of rice starch (RS) were investigated using a high impact planetary mill. After pulverization, RVA characteristics, peak viscosity, break down, and set back values of RS decreased from 274.75 to 9.42 RVU, 214.46 to 6.17 RVU, and 87.80 to 17.00 RVU, respectively. The pasting properties also changed significantly. X-Ray diffractogram revealed RS had four A-type peaks, which disappeared after pulverization. The peak temperature and gelatinization enthalpy of RS using differential scanning calorimetry (DSC) were 13.99 J/g at $75.14^{\circ}C$, whereas the pulverized RS (PRS) had two peaks, 0.13 J/g at $63.88^{\circ}C$ and 1.23 J/g at $101.24^{\circ}C$. DSC measurement showed the retrogradation degree of PRS was lower than that of RS after storage at 4 and $25^{\circ}C$. The enzymatic (${\alpha}$-amylase) digestibilities of RS and PRS were 72.7 and 77.3%, respectively.

Physicochemical Characteristics of Kimchi treated with Chitosan during Fermentation (키토산 첨가에 따른 김치의 숙성 중 이화학적 특성)

  • Park, Bock-Hee;Cho, Hee-Sook;Oh, Bong-Yun
    • Korean Journal of Human Ecology
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    • v.5 no.1
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    • pp.85-93
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    • 2002
  • This study was conducted to examine the effects of chitosan on the changes in physicochemical characteristics and hardness during Kimchi fermentation. The Kimchi samples were stored for 8 days at $20{\pm}l^{\circ}C$. The results were as follows : The pH value was decreased in order of Kimchi treated with 0.05% of 5% chitosan solution(chitosan 0.05%), Kimchi treated with 0.025% of 5% chitosan solution(chitisan 0.025%), Kimchi treated with 0.01% of 5% chitosan solution(chitosan 0.01%) and control, and the total acidity was increased in the opposed order. Volatile acid was increased like the total acidity, it was decreased after 6 days during fermentation, reducing sugar contents of Kimchi samples were decreased gradually. The ascorbic acid contents of Kimchi were increased rapidly in the early stage of fermentation and decreased in the late stage. Properties of hardness of Kimchi measured instrumentally were higher in the Kimchi treated with chitosan than control throughout the fermentation period.

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Effects of Steeping and Washing on Physicochemical Properties of Acorn Flour (수침과 수세가 도토리 묵가루의 이화학적 특성에 미치는 영향)

  • Na, Hwan-Sik;Park, Jong-Hoon;Kim, Kwan
    • Food Science and Preservation
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    • v.5 no.4
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    • pp.368-373
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    • 1998
  • The effects of steeping and washing were investigated in the physicochemical properties of acorn flour. The contents of crude protein, ash and total phenol of acm flour were gradually decreased with the steeping days and washing times. However, the contents of crude fat and dietary fiber were little different. The more steeping days and/or washing times became large, the more the color of acorn flour became light. Swelling power was enhanced by increasing of steeping days and washing times but solubility was some decreased Water binding capacity was decreased and intrinsic viscosity was increased with the increased steeping days and washing times. Washing times were more influential than steeping days to those changes.

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