• Title/Summary/Keyword: Vacuum drying

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Characteristics in the components of the paprika by drying methods

  • Lee, Hyun-Suk;Hong, Ju-Yeon;Choi, Young-Jun;Lee, Yang Suk;Seo, Su-Jeong;Shin, Seung-Ryeul
    • Food Science and Preservation
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    • v.24 no.4
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    • pp.497-504
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    • 2017
  • The aim of this study was to investigate the characteristics of paprika dried by various methods. Moisture content of dried paprika was higher in vacuum freeze-dried red paprika (DRP) (11.85%) than in vacuum freeze-drying of osmotic dried red paprika in sugar (RPS), vacuum freeze-drying of osmotic dried red paprika in fructose (RPF) and vacuum freeze-drying of osmotic dried red paprika in corn syrup (RPCS). Carbohydrate content of DRP was the lowest among the dried groups, but fat, protein, and ash contents were the highest in DRP. The pH of paprika was the highest in RPF (5.34), while it was the lowest in DRP (5.05). Reducing sugar and sugar contents of RPF were 28.59 g/100 g and $5.03^{\circ}Brix$, respectively, which are the highest level among the groups. All color values in inside of paprika were the highest in RPCS, while in outside of paprika, L value is the highest in RPCS, and the value of a, b were the highest in RPS. Regarding the texture characteristics of paprika, strongness, hardness, adhesiveness, chewiness and brittleness were the highest in RPS (p<0.05).

Changes on the Components of Yam Snack by Processing Methods (제조방법에 따른 마 스낵의 성분 변화)

  • Shin Seung-Ryeul
    • Food Science and Preservation
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    • v.11 no.4
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    • pp.516-521
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    • 2004
  • The study was intended to develop a yam snack to increase the consumption and the added value of the yam which has many kinds of medicinal effects and functions. Moisture content of a freeze-drying yam snack was higher than those of hot wind drying and vacuum drying yam snack. However, carbohydrate content was opposed to it. The content of soluble proteins in freeze drying yam snack was 6.43 mg/100g, and lower than that those in hot wind drying and vacuum drying yam snack. The contents of total sugar and reducing sugar were not noticeably different by processing methods. The major organic acids of yam snack were malic, acetic, acids, and acetic acid. Citric acid were rich contented in hot wind and vacuum dried yam snack, but the content of malic acid in freeze dried yam snack was higher than those in hot wind and vacuum dried yam snack. The contents of the amino acids and total amino acids showed the highest contents in vacuum dried snack and the next came in hot wind dried snack and freeze dried snack order. The content of free amino acids were not different by processing methods. Total content of vitamin C were not different by processing methods, but a ascorbic acid was higher in freeze dried yam snack than those in other. The dehydroascorbic acid contents of the hot-air and vacuum dried snack was higher than those of the freeze dried snack, Potassium, sodium and magnesium were the main minerals of the yam snacks.

Quality Characteristics of Vacuum-Dried Gulbi Based on Temperature and Time (온도와 시간에 따른 진공건조 굴비의 품질특성)

  • Park, Hyun Su;Hyun, Myung-Taek;Lee, Ju-Hee;Kim, Dae Young;Lee, Khan;Kim, Hyun Jung
    • Korean journal of food and cookery science
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    • v.33 no.3
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    • pp.316-324
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    • 2017
  • Purpose: Gulbi is a salted and dried yellow corvenia that is popular in Korea. In this study, yellow corvenia was vacuum-dried under two different conditions, average temperatures of $48^{\circ}C$ for 12 and 15 h and $54^{\circ}C$ for 9 and 12 h. Quality characteristics of vacuum-dried Gulbi against fresh corvenia were investigated. Methods: Moisture content, water activity, salt concentration, pH, acidity, volatile basic nitrogen (VBN), thiobarbituric acid-reactive substances (TBARS), and fatty acid composition of Gulbi were evaluated. Results: Moisture contents of fresh corvenia and four types of vacuum-dried Gulbi were 67.37, 31.51, 13.62, 35.17, and 10.05%, respectively. The pH values were in the range of pH 6.70-6.98. The VBN values of Gulbi vacuum-dried at the higher temperature range were greater than those of Gulbi at the lower temperature range. The TBARS of Gulbi increased after vacuum drying (p<0.05). Palmitic acid, palmitoleic acid, oleic acid, and docosahexaenoic acid were the main fatty acids of Gulbi. Conclusion: These results indicate that the quality of vacuum-dried Gulbi is dependent on the drying conditions including temperature and time.

A Study on Sewage Sludge Treatment by Vacuum Drying Method (감압건조법(減壓乾燥法)을 이용(利用)한 하수(下水)슬러지처리(處理))

  • Jang, Seong-Ho;Park, Jin-Sick;Kim, Soo-Saeng
    • Journal of the Korea Organic Resources Recycling Association
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    • v.6 no.1
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    • pp.67-73
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    • 1998
  • This study was to experiment, through sewage sludge treatment by Vacuum Drying Method, variation of water content with reaction pressure, reaction time, reaction temperature. The result are as follows; The water content decreased with the same reaction temperature and reaction time at lower pressure and 360~40 mmHg (a close vacuum) showed lower water content at low reaction temperature and short reaction time. The water content rapidly decreased with the same reaction pressure and time at low reaction temperature (above $120^{\circ}C$).

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Humidity-Controlled Drying of PEG-Treated Waterlogged Woods (PEG처리 수침고목재의 조습건조)

  • Lee, Kwang-Hee;Kim, Soo-Chul;Park, Won-Kyu
    • Journal of Conservation Science
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    • v.27 no.1
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    • pp.91-100
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    • 2011
  • This study is to examine the PEG concentration, and drying humidity and drying periods of humidity-controlled drying(HCD) for conservation of waterlogged woods(Pinus densiflora S. et Z.), and dimension stability of HCD were compared with those of air-drying and vacuum freeze-drying(VFD). Dimension stability of vacuum freeze-drying was the most excellent, i.e., PEG crystal was uniformly distributed in woods. Increasing concentrations of PEG, dimension stability of HCD was increased and drying periods decreased. Dimension stability of HCD after the treatment with the high concentration(70%) of PEG soaking was similar to those of VFD after the treatment with the low concentration(40%) of PEG soaking. In conclusion, high concentration(about 70% in water) PEG solution was the most suitable as a pre-treatment for HCD of waterlogged woods. However, drying should be maintained with enough high humidity and longer period.

Physical Characteristics of Mushroom(Agaricus bisporus) as Influenced by Different Drying Methods (건조방법에 따른 양송이버섯의 물리적 특성에 관한 연구)

  • Ha, Young-Sun;Park, Jong-Won;Lee, Jun-Ho
    • Korean Journal of Food Science and Technology
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    • v.33 no.2
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    • pp.245-251
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    • 2001
  • This research was conducted to study the changes in physical characteristics of mushrooms (Agaricus bisporus) as influenced by drying methods. Samples were dried using either hot air drying, vacuum drying, or freeze drying and changes in the color, browning index, hardness and rehydration rate were evaluated by response surface methodology. Hot air drying resulted in the fastest drying of sample as compared to other methods. The rate of drying was most affected by the environmental temperature rather than air velocity or vacuum pressure. The overall color difference increased as the temperature and air velocity increased. The overall color changes of the freeze dried samples were minimal as compared to those of fresh mushrooms. The hot air dried samples showed the greatest changes in the overall color, browning index as well as hardness. The freeze dried samples showed the best rehydration characteristic and maintained the best overall quality after drying.

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Model of Drying Stress Distribution in Disks End-wrapped in Korean Paper and Effects of End-wrappings on Prevention of Drying Defects for Vacuum Drying of Disks (한지(韓紙) 엔드래핑처리 원판(圓板)의 감압건조응력(減壓乾燥應力) 분포모형(分布模型) 및 엔드래핑스의 건조결함(乾燥缺陷) 예방효과(豫防效果))

  • Lee, Nam-Ho;Jung, Hee-Suk
    • Journal of the Korean Wood Science and Technology
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    • v.19 no.1
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    • pp.31-63
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    • 1991
  • It was proved that in conventional kiln drying of disks piling position in the kiln exerted a great influence on drying rates, and the larger the variation of disk diameter, the more undulating drying rates of disks. While in vacuum drying disks there was no influence on drying rates. By the end-wrapping treatments and the radial direction of disks tangential surface stresses in the core of disks were slightly compressive in three species. In control disks the drying stresses distributed into one step-style that compressive stresses in the pith side of 6cm from pith were larger than those in the bark side, while in the disks end-wrapped with Korean paper the drying stresses distributed uniformly, because flow rates of free water in disks had no difference between heart-and sap-wood by obstruction of evaporating water from surface of disks by end-wrapping with Korean paper. And end-wrapping with Korean paper considerably restrained those. Tangential differential shrinkage stresses developed the maximum tensile stress near the bark and with approaching the pith the stresses gradually reduced and changed into compressive stresses in near the pith. At the end of vacuum drying the maximum tangential tensile stresses of disks end-wrapped with Korean paper were smaller than those of control disks, and critical moisture contents causing the V-shaped crack of disks end-wrapped with Korean paper were lower than those of control disks because of the set by obstruction of evaporating water of end-wrapping with Korean paper. In the experiment of vacuum drying stress distribution the disks end-wrapped with Korean paper or aluminum foil in three species were free from V-shaped cracks and control disks were defected very slightly by V-shaped cracks. And also disks end-wrapped with Korean paper were free from heart checks in Alnus japonica and Juglans sinensis, and heart checks were occurred very slightly in others. Especially, not to speak of disks end-wrapped with Korean paper, vacuum drying of disks end-wrapped with aluminum foil prevented effectively drying defects, moreover drying times could be shortened, that is. Ginkgo biloba, Alnus japonica, and Juglans sinensis disks could be dried from green to in-use moisture content in 110 hours, 272 hours, and 407 hours, respectively.

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Optimization of Vacuum Drying Conditions for a Steamed (Pumpkin-) Sweet Potato Slab by Response Surface Methodology (반응표면분석법을 이용한 증절간 (호박)고구마의 최적 진공건조조건 설정)

  • Shin, Mi-Young;Youn, Kwang-Sup;Lee, Su-Won;Moon, Hye-Kyung;Lee, Won-Young
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.40 no.9
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    • pp.1314-1320
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    • 2011
  • Vacuum drying was conducted for a steamed pumpkin-sweet potato slab to improve its quality, convenience and preference as snack. Steamed sweet potato was dried from 30 to $60^{\circ}C$ for 12 hr, after which moisture contents, colors, and taste were evaluated. The lowest moisture content was 0.22% upon vacuum drying at $60^{\circ}C$ for 12 hr. Lightness decreased while other color values (a, b and ${\Delta}E$) increased with increasing drying temperature and drying time. Reducing sugar and soluble solid contents ranged from 98.7~268.11 mg/g and $19{\sim}72^{\circ}Brix$, respectively. Sensory score of the sample was the highest when dried at $50^{\circ}C$ for 6 hr. The optimum drying conditions were predicted to be $48.5{\sim}62^{\circ}C$ and 5.1~7.1 hr by response surface methodology.

Design and Evaluation of a Microcomputer-based Vacuum Drying System for Shiitake Mushrooms (마이크로컴퓨터 시스템을 이용한 표고버섯의 감압건조에 대한 연구)

  • Choi, Jae-Yong;Kim, Kong-Hwan;Chun, Jae-Kun
    • Korean Journal of Food Science and Technology
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    • v.19 no.6
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    • pp.550-555
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    • 1987
  • Strain gauges attached on the Bourdon tube and load cell were used as the sensors for measuring the vacuum pressure in drying chamber and the weight loss of Shiitake mushrooms respectively. The vacuum drying system was interfaced further with the Bear II microcomputer. The interface devices used were built with such IC chips as MC 6821, ADC 0809, SN 74244 and SN 7424. The relationship between readings of vacuum gauge (P, mmHg) and digital outputs (D) from the microcomputer was represented by P =3.08 D-13.4875(r=0.9999). The weights of drying sample (W) were also related with the digital outputs (D) by W=0.4076 D-6.4762 (r=0.9999). During the vacuum drying of Shiitake mushrooms. the data on pressure and weight were recorded at regular intervals using an acquisition program on the microcomputer system. The Page model was fitted well to the drying data of Shiitake mushrooms. resulting in the following empirical equations : $(M-M_e)/(M_o-M_e)=\exp(-0.1569t^{1.0048})$ at 400 mm Hg up to 14 hours and $(M-M_e)/(M_o-M_e)=\exp(-0.1385_t^{1.2688})$ at 600 mm Hg up to 8 hours.

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Physicochemical Properties of Onion Powder as Influenced by Drying Methods (건조방법에 따른 양파분말의 품질특성)

  • Kim, Hye-Ran;Seog, Eun-Ju;Lee, Jun-Ho;Rhim, Jong-Whan
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.36 no.3
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    • pp.342-347
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    • 2007
  • Physicochemical properties of onion powder as influenced by drying methods were investigated. Moisture contents of onion powder were 13.29%, 12.99%, and 10.78% for samples dried using hot-air dryer, freeze dryer, and vacuum dryer, respectively. There were no significant differences in crude fat, crude protein, and crude ash content (p>0.05) depending on the drying methods. Samples prepared by freeze drying showed a significantly higher L-value as compared with those prepared by hot-air and vacuum drying (p<0.05). Scanning electron micrographs showed that freeze drying produced smaller particle-sized sample which in turn resulted in the higher porosity of the sample. Freeze dried samples revealed significantly lower degree of rehydration than other samples (p<0.05) probably due to small particle size of the sample. Water solubility of freeze dried sample appeared to be higher than that of other drying methods while the swelling ratio of the same sample appeared to be lower than that of the others. Browning index was significantly lower in samples prepared by freeze drying (p<0.05) but not significantly different between samples dried by hot-air and vacuum drying. Vitamin C content was higher in freeze dried onion powder due to the lower temperature applied to the sample. Freeze dried onion powder contained significantly lower amount of total polyphenol and higher amount of total sugar as compared to other samples (p<0.05).