• Title/Summary/Keyword: Physicochemical changes

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Changes in the Physicochemical Characteristics of Sweet Corn Kernels during Grain Filling Stage with Different Sowing Date (단옥수수 주요 품종의 등숙 중 종실 이화학적 특성 변화)

  • Kim, Mi-Jung;Park, Hyo-Jin;Kim, Sun-Lim;Jung, Gun-Ho;Kim, Jung-Tae;Shin, Seong-Hyu;Kwon, Young-Up;Chung, Ill-Min
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.59 no.4
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    • pp.445-456
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    • 2014
  • This study was conducted to investigate the kernel characteristics of sweet corn during ripening with different sowing date. Godangok and Guseulok were sown at April 10, July 10, July 20, and July 30 in 2013. Irrespective of sowing date, fresh and dry weight of 100 kernel, starch content, crude fat content, and hardness of sweet corn kernels were significantly increased according to maturation (p<0.05). But moisture content, total sugar content, crude protein content and crude ash content of sweet corn kernels were significantly decreased according to maturation (p<0.05). The changing rates of 100 kernel weight and starch content on kernels were faster at early sowing date than at late sowing date. The moisture content of sweet corn kernels was 68~69% at optimum for harvesting. The degree of sweetness on Godangok was about 1.8 and 1.4 times higher in sowing at July 20 and July 30 than in sowing at April 10. On the other hand, the degree of sweetness was similar regardless of sowing time on Guseulok. These results will be helpful to farmers for fall-harvest sweet corn cultivation and management.

Effect of Rice Flour Sourdough Fermented with Omija (Schizandra chinensis) Extract on Quality Characteristics of Bread (오미자청을 이용한 쌀가루 sourdough 첨가 식빵의 품질 특성)

  • Byun, Jong-Beom;Chang, Jin-Hee;Jeoung, Gey-Yeoun;Lee, Jin-Sil
    • Korean Journal of Food Science and Technology
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    • v.47 no.6
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    • pp.704-710
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    • 2015
  • The objective of this work was to examine the effect of rice flour sourdough fermented with omija (Schizandra chinensis) extract on the quality characteristics of bread. Five rice sourdough concentrations (0, 15, 30, 45, and 60%) were used in order to ascertain the best bread composition. Bread qualities were determined by means of physicochemical analysis and consumer acceptability test. The results showed that the dough prepared with 15% rice flour sourdough fermented with omija extract had a positive impact on the bread quality such as volume, hardness, springiness, and consumer acceptability. This study suggests that the rice flour sourdough fermented with omija extract could be added up to 15% without quality changes for making bread.

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.

Effect of Fermentation Temperature on the Physicochemical Properties of Mustard Leaf(Brassica juncea) Kimchi during Various Storage Days (발효숙성온도를 달리한 갓 김치의 저장중 이화학적 특성 변화)

  • 박삼수;장명숙;이규환
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.24 no.5
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    • pp.752-757
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    • 1995
  • The effect of fermentation temperature on the changes of pH, acidity, salt content, color and vitamin C of mustard leaf kimchi during various storage days was investigated. The conditions of fermentation temperature were set at $4^{\circ}C$ (sample A) and $20^{\circ}C$ (sample B), and $4^{\circ}C$ after keeping at $20^{\circ}C$ for 12 hours(sample C) and $20^{\circ}C$ for 36 hours(sample D). As the fermentation proceeded, pH of sample stored at low temperature(sample A) was drop ped gradually from initial pH of 5.24 but there was great pH drop in the sample stored at high temperature(sample B, D). The salt content of the sample B at high temperature increased remarkably, and then the values showed D > A > C. The Humter values of L and a increased at the optimum ripening period, the higher the initial fermentation temperature(B) and the later the initial fermentation time at $20^{\circ}C$ those values, then decreased. The Hunter value of b constantly increased until day of 108. As fermentation time passed, the content of total vitamin C decreased to the range of 9.0mg% to 14.0mg% up to 24 days of fermentation, and at the optimum ripening period, it increased to the range of 14.0mg% to 22.0mg%, and at the fermentation period(until day 108), it decreased gradually.

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Effect of Ecklonia cava on the Quality Kimchi during Fermentation (감태 첨가가 배추김치의 숙성 중 품질에 미치는 영향)

  • Lee, Hyun-Ah;Song, Yeong-Ok;Jang, Mi-Soon;Han, Ji-Sook
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.1
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    • pp.83-88
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    • 2013
  • To improve kimchi qualities, Ecklonia (E.) cava of 5%, 15% or 25% were added and the qualities investigated by measuring changes in physicochemical, microbiological, and sensory characteristics during fermentation at $5^{\circ}C$. The pH of kimchi with E. cava added decreased and acidity increased. The number of Leuconostoc sp. in kimchi reached its maximum at the optimum fermenting stage, the $16^{th}$ day in control kimchi and the $20^{th}$ day in the kimchi added E. cava. The optimum fermenting stage of the kimchi was retarded due to adding the E. cava. The reducing sugar contents was highest in kimchi with 25% E. cava during the early stage of fermentation. According to Hunter's color values, the lightness of the kimchi with E. cava added decreased during fermentation, while the redness increased as fermentation proceeded. The sensory scores for overall acceptance, taste, texture and appearance were highest in kimchi with 15% E. cava.

Changes in Physicochemical Characteristics of Green Barley according to Days after Heading (출수 후 일수에 따른 쌀보리 종실의 이화학적 특성 변화)

  • Ju, Jung-Il;Lee, Ka-Soon;Min, Hee-Il;Lee, Byung-Jin;Kwon, Byung-Gu;Gu, Ja-Hyeong;Oh, Man-Jin
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.52 no.1
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    • pp.36-44
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    • 2007
  • In order to evaluate the utilization of immature green barley kernels as food processing material, these experiments were carried out to analyze free sugars, free amino acids, mineral contents and color of two naked barley varieties according to their heading dates. Contents such as moisture, protein, fat, ash, and free sugars were gradually decreased according to the days after heading of the nonwaxy naked barley 'Saessalbori' and waxy naked barley 'Hinchalssalbori', while crude fiber and starch were gradually increased. Contents like maltose and maltotriose in immature green kernels were high, but free amino acids showed a tendency to decrease, among which the alanine content was the highest. As barley matured, beta-glucan content, redness and yellowness increased, while lightness decreased. Considering chemical composition and color, the immature green cereals were produced through blanching the spikes harvested before the yellow ripe stage around $26{\sim}27$ days after heading. The optimum duration of harvest was very limited to produce green whole grains. The harvested green barley cereals is able to eat raw barley or cook it as food processing material.

Comparing the Quality Characteristics of Lactose-Hydrolyzed Low-Fat Milk (유당분해율에 따른 저지방 유당분해우유의 품질 특성)

  • Jeong, Da Hye;Shin, Yong Kook;Kang, Shin Ho
    • Journal of Dairy Science and Biotechnology
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    • v.35 no.1
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    • pp.39-45
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    • 2017
  • The market for lactose-hydrolyzed milk is growing due to an increased awareness of lactose intolerance, and increased market interest for modified milk with health claims. The aim of this study was to compare the quality characteristics of 2% lactose-hydrolyzed milk with its lactose hydrolysis rate, with the goal of applying the method to dairy product monitoring in the future. We observed that the freezing point of milk significantly decreased with increasing lactose hydrolysis rate. A linear relationship was found between lactose concentration and freezing point, following the equation (y=-50.416x + 767.91). However, no significant changes were observed in other physicochemical properties of the milk (pH, titratable acidity, total solids and color) (p<0.05). In conclusion, we could predict the residual lactose content quickly and easily in 2% low fat milk by measuring its freezing point. This could represent an easy means for assessing the lactose hydrolysis rate of dairy products.

Changes in Physicochemical Characteristics of Black Raspberry Wines from Different Regions During Fermentation (국내 복분자 주요 산지별 복분자주 제조 및 발효특성 분석)

  • Lee, Seung-Joo;Ahn, Bo-Mi
    • Korean Journal of Food Science and Technology
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    • v.41 no.6
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    • pp.662-667
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    • 2009
  • In this study, four Korean black raspberry wines were developed using raspberries from different regions in Korea; Gochang (G), Hoengseong (H), Jeongeup (J), Sunchang (S). Sample wines were monitored for titratable acidity, ethanol, pH, reducing sugar content, color intensity, hue, total phenolic content, and organic acids during alcoholic fermentation and aging. After fermentation was complete, the pH levels in the four wines were in a similar range (3.43-3.52), while total acidity levels ranged from 9.98 to 16.2 g/L, which were significantly different among the four wines. During 120 days of aging, the ethanol content ranged from 15.8 to 16.40% which corresponds to a good conversion rate of sugars. Among the four samples tested, the wine made with Jeongeup raspberries showed the highest levels of total phenolic content, and other color values such as hue and intensity. The predominant organic acids were citric acids (3.30-4.89 mg/mL) and succinic acids (1.92-3.48 mg/mL). Overall the wine made with Jeongeup raspberries showed differences in physico-chemical compositions compared to the other wines made with Gochang, Hoengseong, and Sunchang raspberries, respectively.

Physicochemical Properties and Antioxidative Activity of Lactic Acid Bacteria Fermented Rhodiola sachalinensis using Adsorption Process (흡착 공정을 활용한 홍경천(Rhodiola sachalinensis) 유산균 발효물의 이화학적 특성 및 항산화 활성)

  • Sung, Su-Kyung;Rhee, Young-Kyung;Cho, Chang-Won;Lee, Young-Chul;Kim, Young-Chan;Hong, Hee-Do
    • The Korean Journal of Food And Nutrition
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    • v.25 no.4
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    • pp.779-786
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    • 2012
  • Rhodiola sachalinensis fermentates by lactic acid bacteria were prepared using the adsorption process, and were investigated for changes of the main compounds and anti-oxidative activities during the adsorption and fermentation process. While the R. sachalinensis extract (RSE), which did not go through the adsorption process, showed little change in pH during fermentation and a significant reduction in the number of lactic acid bacteria, the pre-preparatory adsorption process was found to be helpful for promoting fermentation and for maintenance of bacterial numbers. The contents of total phenolic compounds mostly decreased during the adsorption process, but showed an increasing tendency to rebound during the fermentation process. The contents of salidroside and p-tyrosol in the RSE were 1153.3 mg% and 185.0 mg% respectively, and they did not significantly change after treatment with acid clay or bentonite as adsorbents, which were 1093.0 and 190.5 mg% by acid clay, and 882.2 and 157.3 mg% by bentonite. When the extract was fermented after treatment with acid clay or bentonite, the salidroside contents were decreased by 282.7 and 505.0 mg% respectively, but the p-tyrosol contents were increased by 714.0 and 522.4 mg% respectively. Compared to the DPPH radical scavenging activity of the RSE (66.8%) at the conc. of 0.1%, that of the fermented RSE, which went through adsorption process with acid clay or bentonite, was significantly increased to 79.4 and 72.7% respectively at the same concentration (p<0.05). Though fermentation by lactic acid bacteria was suppressed in the RSE, the results suggested that the adsorption process may promote fermentation without any change in the content of major active compounds. It is expected that fermentation by lactic acid bacteria could improve the antioxidant activity and various associated functionalities of R. sachalinensis.

Changes in Quality of according to Fermentation Time of Fermented Soybean Produced Made with Bacillus amyloliquefaciens (Bacillus amyloliquefaciens로 제조한 콩 발효물의 발효시간에 따른 품질 변화)

  • Shin, Dong Sun;Choi, In Duck;Park, Ji Young;Kim, Nam Geol;Lee, Seuk Ki;Jeong, Kwang-Ho;Park, Chang Hwan;Choi, Hye Sun
    • The Korean Journal of Food And Nutrition
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    • v.33 no.4
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    • pp.381-389
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    • 2020
  • The purpose of this study was to evaluate the appearance, physicochemical, physical, and fermentation properties of the fermented soybean produced by manufacturing with inoculation the different types of microbial strains. The strains were inoculated by the NSI (natural strains inoculation), and the SSI (selective strain inoculation) were treatments. The appearance showed differences in color, viscous substance, and hardness depending on strains inoculation and fermentation duration. The pH, and total acidity were 6.40~7.26%, and 0.10~0.39% respectively with differences depending on the samples. The moisture content as the fermentation duration increased, the NSI (56.03~57.66%) decreased and the SSI (56.71~58.63%) increased. The physical characteristics of the hardness increased as the fermentation duration increased for the NSI and the SSI decreased. The color values for the L, a, and b values were 47.64~58.56, 7.15~9.08, and 12.41~17.30, respectively. The α-amylase and protease activities of the SSI were the highest among all treatments. The total viable cell counts of the fermented soybean products by strains were 5.02 to 9.77 log CFU/g, and SSI (fermentation, 48 hours) was the highest. The amino-type nitrogen contents of all samples were 301.62~746.97 mg% and the SSI showed the highest content. The amino acid had the highest glutamic acid content.