• Title/Summary/Keyword: Physicochemical change

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Physicochemical Characteristics of Sangju Traditional Dried Persimmons during Drying Process (상주 전통곶감의 제조과정 중 이화학적 품질특성)

  • 강우원;김종국;오상룡;김준한;한진희;양진무;최종욱
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.33 no.2
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    • pp.386-391
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    • 2004
  • This study was performed to investigate change of quality characteristics on traditional dried Persimmons from Sangju varity regions (sun-dried, Namjang and Bokryong). Moisture contents on drying were decreased and constant at from 7th to 14th days drying periods and its periods were recognized to constructing second peel of dried persimmons. Constructed second peel were affected on quality characteristics of traditional dried Persimmons. Also, in case of semi-dried persimmons were processed at 45∼55% level of moisture content. Final products of semi -dried persimmons were estimated in 25th from initial drying periods. Changes of water activity were increased reducing speed at time of water content decreased, second feel constructing during drying persimmons were introduced to decreasing of water activity. Weights of dried Persimmons were quickly decreased in 21th drying periods and slowly decreased after that time. Weight changing and water evaporation of dried persimmons at the Namjang and Bokryong were slowy decreased and controled after 7∼14th in periods of constructing second feel of dried persimmons. Change of brix in dried persimmons have had in 18∼27% value at initial drying periods and quickly increased after 7∼14th in drying periods and have in high value of 40∼50% at 21th drying periods. At the texture of dried persimmons, hardness were decresed after 7∼14th in periods and effected on decreasing of water content, increasing of drying times. Sensory score of dried persimmons were highest score of color, sweetness and texture at dried persimmons of Namjang. Score of astringency, sourness and mold smell were highest at dried persimmons of Bokryong. Value of highest overall acceptance score was at dried Persimmons of Namjang.

Change of Phytoplankton Community by Ultrasonication in Eutrophic Ponds (부영양 연못에서 초음파 작동에 따른 식물플랑크톤의 군집 변화)

  • Ko, So-Ra;Ahn, Chi-Yong;Joung, Seung-Hyun;Kim, Hee-Sik;Oh, Hee-Mock
    • Korean Journal of Environmental Biology
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    • v.24 no.3
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    • pp.221-229
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    • 2006
  • The effects of ultrasonication on phytoplankton were investigated in two ponds in which physicochemical and biological water quality was similar, one as a treatment and the other as a control. The samples were collected from August 18 to September 30 in 2003. Traditional morphological analysis showed that Bacillariophyceae dominated phytoplankton community in both ponds. The abundance of Cyanophyceae was lower in the phytoplankton community of the sonicated pond than that of control pond. We used DGGE (denaturing gradient gel electrophoresis) to analyze the diversity and change of phytoplankton community in two ponds. The DGGE banding patterns of 16S rRNA gene and sequence analysis demonstrated that Oscillatoria acuminata and CFB (Cytophaga-Flavobacterium-Bacteroides) group bacterium appeared in the treated pond, and the control pond was dominated by Synechococcus sp. and Aphanizomenon flos-aquae. Especially, Pseudanabaena sp. dominated during the ultrasonic cessation in the treated pond. The DGGE profiles of 18S rRNA gene and sequence analysis showed that the treated pond was dominated by Chlamydomonas reinhardtii and the control pond by C. reinhardtii and Pteromonas protracta. In conclusion, the ultrasonication affected the reduced growth of cyanobacteria, particularly Pseudanabaena.

Changes in Quality of Domestic Apple Juice Concentrates during Long-term Storage (국내산 사과주스 농축품의 장기 저장 중 품질 변화)

  • Kim, Sung-Soo;Kim, Kyung-Tack;Choi, Hee-Don;Hong, Hee-Do
    • Applied Biological Chemistry
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    • v.42 no.3
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    • pp.235-239
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    • 1999
  • During storage of $45^{\circ}Bx$ cloudy, $50^{\circ}Bx\;and\;72^{\circ}Bx$ clear apple juice concentrates for 18 months, the changes in microbial counts and physicochemical properties were investigated. Little viable microbial counts were detected in $50^{\circ}Bx\;and\;72^{\circ}Bx$ clear concentrates during all storage time and a few in $45^{\circ}Bx$ cloudy concentrates during the only first storage stage. In all three concentrates, any changes were not found in pH and titrable acidity. But Hunter L values were decreased and a, b values were increased. Alcohol soluble color(ASC) were increased and vitamin C contents rapidly decreased, especially during the first three months. The contents and compositions of free sugars were showed a little change. It seemed that the change in ASC was more closely related with that of vitamin C contents than that of reducing sugar contents.

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Effect of Freezing on the Physicochemical Properties of Semi-dried Red Pepper (냉동조건에 따른 반건조 홍고추의 물리.화학적 특성 변화)

  • Kim, Bo-Yeon;Lee, Kyoung-Hae
    • Food Science and Preservation
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    • v.16 no.3
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    • pp.362-370
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    • 2009
  • Quality changes in semi-dried red pepper (SRP) treated with ozone water were observed upon storage (at $-18^{\circ}C$) after freezing at $-10^{\circ}C$, $-20^{\circ}C$, and $-40^{\circ}C$. Drip loss after treatment was greater than in control peppers, but no significant difference was evident between treatments (p<0.05). We observed that differences between samples decreased as storage time increased. Texture after treatment did not change significantly over a 3-month period. The redness (a-value) after treatment was greater than in the control, but no sample showed significant color alteration after the 3-month period. The capsaicinoid content decreasedas storage time increased, and was also affected by the freezing temperature. However, carotenoid content was not influenced by freezing or storage temperature. Ascorbic acid and free sugar contents showed decreases of 47% and 6.5%, respectively, after semi-drying. The results of sensory evaluation indicated no significant difference between samples in terms of color appearance.

An Effect of Revolutions Per Minute (r.p.m) in the Noise Characteristics (기계소(機械騷) 음(音)과 회전(回轉) 속도(速度))

  • Cha, Bong-Suk
    • Journal of Preventive Medicine and Public Health
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    • v.10 no.1
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    • pp.94-101
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    • 1977
  • Noise pollution, both in the environment and in the workplace, has been recognized as a major health hazard -one that can impair not only a person's hearing but also his physical and mental well-being. As industrialization progresses, the prevalence rate of occupational diseases is increasing, especially hearing loss, which has the highest prevalence rate among the occupational diseases. The major cause of noise is the construction of various large industries without any regulation of noise sources. Therefor, we must establish an enactment to control mechanical noise sources. as soon as possible. For the purpose of controlling the noise source, we must have exact data about such things as the sound level, the frequency of the peak sound and the revolutions per minute (r.p.m.) of the machine (a measure of the power of its motor). This study was undertaken in order to define the noise characteristics, the power of the machine's motor, the change of the sound level and the peak sound as the r.p.m. increases, and the permissible exposure time. The sample size of this study was 74 machines at 11 plants in 6 industries. The results are as follows; 1. The breakdown of the types of mechanical noise noted was : 63.6% continuous normal sound, 26.9% intermittent sound, 4.7% continuous repeating sound and 4.6% impulsive sound. 2. With respect to the type of industry, the overall sound level was the highest in the mechanical industry, with $103.8{\pm}2.8dB(A)$, and lowest in the textile industry, with $89.2{\pm}1.43dB(A)$. 3. With respect to the type of machine, the highest sound level was 124 dB(A) caused by Gauzing(II), in the mechanical industry, and the lowest was 76 dB(A) caused by Attachment (Jup Chack) (I) in the timber industry. 4. The shortest permissible exposure time to Gauzing(II) in the mechanical industry was less than 15 minutes. 5. Among 74 machines, 68.2% of the peak sound was situated in the high frequency range (52.7% at 2 KHz, 4.1% at 4 KHz and 1.4% at 8 KHz). 41.8% of the peak sound was in the middle frequency range (4.1% at 250Hz, 14.8% at 500Hz and 22.9% at 1KHz). 6. If one machine had two motors or more, the peak sound was shifted to the low frequency range. 7. As the r.p.m. increased, the overall and peak sound levels were increased without any change of the frequency of the peak sound. 8. Whenever the machines had the same kind and the same r.p.m., the overall and peak sounds were changed by the physicochemical characteristics of the raw materials and the management.

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Effect of Oil Addition on Texture of Mungbean Starch Gel (지방첨가가 녹두전분 Gel의 Texture에 미치는 영향 -제1보 : 이화학적 특성 및 기계적 검사에 의한 평가)

  • 주나미;전희정
    • Korean journal of food and cookery science
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    • v.7 no.4
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    • pp.63-69
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    • 1991
  • This study was undertaken for the purpose of studying the physicochemical propery of mungbean and texture of mungbean starch gels. Mungbean starch gel made with different levels of oil were tested to investigate the textural characteristics by mechanical test. The results are summerized as fallows: The content of moisture fat, protein, and ash in Seonwha mungbean were shown to be about 13.19%, 1.02%, 23.57% 3.13% respectively. Those of Seonwha mungbean crude starch were 12.48%, 0.63%, 0.94%, 0.13% respectively. The gain of dry crude starch from peeled mungbean was 22.48%. Water binding capacity of Seonwha mungbean crude starch was 183.1%. The pattern of change in swelling power of Seonwha mungbean crude starch for increasing temperature increased slowly to $70^{\circ}C$, and then increased rapidly. The pattern of change in solubility was similar to that of swelling power. The amylose and amylopectin content were 22.5%, 77.5%. Brabender hot-paste viscosities of mungbean crude starch at 8% and 10% showed the similar amylogram patterns with peak vicosity. By the Rheometer measurement result of 8% 10% mungbean starch gel, Hardness and Fractuability tended to be decreased as the addition level of oil increased. Elasticity, Adhesiveness, Chewiness, L, a, and b value tended to be increased as the addition level of oil increased.

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Effect of Red Beet on Quality and Color Stability of Low-fat Sausages during Refrigerated Storage (레드 비트의 첨가가 냉장저장 중 저지방 소시지의 품질과 발색 안정성에 미치는 영향)

  • Jeong, Ho-Jin;Lee, Hong-Chul;Chin, Koo-Bok
    • Food Science of Animal Resources
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    • v.30 no.6
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    • pp.1014-1023
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    • 2010
  • This study was performed to evaluate the quality characteristics of low-fat boiled or smoked sausages containing sodium nitrite and various levels of red beet during refrigerated storage. Physicochemical properties of boiled and smoked sausages were not affected by the addition of red beet (p>0.05), except for the color values. The interaction between treatment and storage time had significant effects on redness and yellowness of boiled sausages, and on redness of smoked sausages (p<0.05). Boiled sausages containing more than 0.5% red beet decreased lightness and increased redness and yellowness (p<0.05). During storage time, redness decreased and yellowness increased (p<0.05). The combination of sodium nitrite with red beet was better than red beet alone for color stability. In the smoked sausages, addition of red beet decreased lightness, but redness (p<0.05), unlike the boiled sausages, did not change. Redness of sausages containing red beet alone decreased with increased storage time (p<0.05), but there was no change (p>0.05) upon treatment with the combination of sodium nitrite and red beet. These results indicate that the combination of red beet and sodium nitrite contributed to color stability of smoked sausages during refrigerated storage. Therefore, we suggest that red beet as a natural colorant may be used to reduce the content of nitrite during low-fat sausage processing.

Physico-Chemical Properties of Modified Rice Flour by Physical Modification (드럼건조에 의한 쌀가루의 특성)

  • Kum, Jun-Seok;Lee, Hyun-Yu;Shin, Myoung-Gon;Lee, Sang-Hyo;Kim, Kil-Hwan
    • Applied Biological Chemistry
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    • v.37 no.3
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    • pp.154-160
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    • 1994
  • Pregelitinized rice (PR), pregelitinized waxy rice (PWR), and pregelitinized rice flour (PRF) were evaluated for physico-chemical properties comparing with rice starch and acetylated potato starch. L value was decreased during drum drying. PFR had the highest value (P<0.05) for water absorption index and PWR had the highest value for water solubility index. Transmittance of gelitinized samples had drastically increased at $80{\sim}90^{\circ}C$. PWR had the highest value for apparent viscosity and rice samples had a steady apparent viscosity during heating at $90^{\circ}C$. Viscosity was decreased as pH decreased at room temperature and drastically decreased below pH 2. Rice starch and PR had no significant effect for change of pH. Change of viscosity had more effect for hot temp. than room temp.. Pregelitinized samples showed only second peak for DSC. PWR had the lowest value for degree of retrogradation and acetylated potato starch had the highest value for freeze-thaw-stability.

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Effect of pretreatment and packaging methods on quality of cold vacuum dried peach (전처리 및 포장방법이 냉풍감압건조 복숭아의 품질에 미치는 영향)

  • Kwon, Gi-Man;Kim, Jae-Won;Youn, Kwang-Sup
    • Food Science and Preservation
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    • v.20 no.3
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    • pp.317-322
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    • 2013
  • This study was conducted to investigate the effects of pretreatment and different packaging methods on the physicochemical properties of cold vacuum-dried peaches. All the dried peach samples were stored such as $N_2$ gas substitution, vacuum and passive packaged with polyethylene (PE) film and oriented polypropylene (OPP)/aluminum (Al)/PE film at $40^{\circ}C$ for 50 days. The weight change, pH, soluble solids content, titratable acidity, soluble solid-acid ratio (SS/TA), delta E, browning degree and phenolic compounds were analyzed. The weight change and pH were lower in the 0.1% vitamin C-treated group and were significantly lowest in the vacuum-treated OPP/AL/PE. The soluble solids content and the SS/TA were higher in the non-treated groups than in the vitamin C-treated groups. According to the packaging methods, the $L^*$ values were higher in the vacuum, $N_2$ gas and passive package, in that order. In addition, the browning degree and the delta E value were lower in the pretreated groups and significantly lowest in the vacuum-treated OPP/AL/PE with 0.1% vitamin C group. The phenolic compounds were high for the pretreated groups, according to the packaging methods (vacuum > $N_2$ gas> passive), and the OPP/AL/PE was significantly higher than the PE. These results suggest that different packaging materials and pretreatment methods affected the quality of the dried peaches, and the vacuum-OPP/AL/PE film packaging group showed a high quality.

Gelling Characteristics of Mung Bean Starch Supplemented with Gelatin and Isolated Soy Protein (젤라틴, 분리대두단백 첨가가 녹두전분의 겔특성에 미치는 영향)

  • Choi, Eun Jung;Oh, Myung Suk
    • Journal of the Korean Society of Food Culture
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    • v.28 no.6
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    • pp.664-673
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    • 2013
  • This study was conducted to investigate the physicochemical properties of mung bean starch and the quality characteristics of mung bean starch gels supplemented with gelatin and isolated soy protein (0, 2, 5%) during storage at $5^{\circ}C$ for 0, 24, 48, and 72 hours. The swelling power of mung bean starch supplemented with gelatin did not significantly change, whereas those supplemented with isolated soy protein (ISP) significantly increased. The solubility of mung bean starch supplemented with gelatin and ISP, however, significantly increased with increasing concentration. In addition, the soluble amylose and soluble carbohydrate of mung bean starch supplemented with gelatin and ISP significantly decreased with increasing concentration. In terms of pasting properties measured by the Rapid Visco Analyzer (RVA), the pasting temperature of mung bean starch supplemented with gelatin and ISP was not significantly different, whereas peak viscosity, minimum viscosity, final viscosity, breakdown, and consistency decreased. DSC thermograms showed that the onset temperature of mung bean starch supplemented with gelatin and ISP did not significantly change, whereas the enthalpy increased with the addition of 5% ISP. The lightness (L) and redness (a) of mung bean starch gels supplemented with gelatin, ISP, and without additives increased during cold storage, whereas the yellowness (b) decreased. The addition of gelatin and ISP suppressed changes in L, a and b of mung bean starch gel during cold storage. Synereses of mung bean starch gel supplemented with gelatin and ISP was lower than that without additives, with the addition of gelatin suppressing synereses more than ISP. The addition of gelatin and ISP also suppressed increases in hardness, chewiness, and gumminess of mung bean starch gels during cold storage. In the sensory evaluation, the addition of gelatin and ISP suppressed increases in hardness and brittleness of mung bean starch gels during cold storage. The addition of 2%, 5% gelatin and 2% ISP also suppressed a decrease in the overall acceptability of mung bean starch gels during 24-48 hr cold storage. Thus, the addition of 2-5% gelatin and 2% ISP to mung bean starch is appropriate for suppressing the quality deterioration of 24-48 hr cold-stored mung bean starch gels.