• Title/Summary/Keyword: titratable acid

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Effect of Copper Ions on Over-Acidification of kimchi (구리 이온의 김치산패 억제작용에 관한 연구)

  • 채경연;유양자;경규항;박세원;김연순
    • Korean journal of food and cookery science
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    • v.18 no.1
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    • pp.87-93
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    • 2002
  • Effect of copper ions (Cu$\^$+/ and Cu$\^$2+/) on the fermentation of kimchi, especially on their effect on the prevention of over-acidification of kimchi, was investigated. The effect of Cu$\^$2+/ ion on the growth of individual lactic acid bacterium originally isolated from kimchi was also investigated. The addition of Cu$\^$+/($\geq$4.0mM) or Cu$\^$2+/($\geq$3.0mM) ions in kimchi effectively inhibited growth of lactic acid bacteria and maintained a titratable acidity of less than 1.0% for a periods of 14 days. Leuconostoc mesenteroides significantly decreased at the 10th day of fermentation in control kimchi, whereas the group with Cu$\^$+/ and Cu$\^$2+/ showed 10$\^$5/-10$\^$6/ CFU/ml at the 14th day of fermentation. This indicates that the addition of Cu$\^$+/ and Cu$\^$2+/ inhibited the production of excessive acids by inhibiting lactic acid bacteria, and allowed Leu. mesenteroides stay alive longer. Fe$\^$2+/ and SO$_4$$\^$2-/ ions did not have any effect on the fermentation of kimchi. Cu$\^$2+/ inhibited growth of all lactic acid bacteria tested, such as Leu. mesenteroides 6, Streptococcus faecalis 12, Lactobacillus plantarum 14, Lac. brevis 15, Leu. mesenteroides LA 10, and Lac. plantarum LA 97.

Changes in Chemical Components of Korean Kiwifruit(Actinidia deliciosa) by Storage Temperature (저장온도에 따른 한국산 양다래(Actinidia deliciosa)의 화학적 성분의 변화)

  • Kim, Jung-Min;Ko, Young-Su
    • Korean Journal of Food Science and Technology
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    • v.29 no.4
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    • pp.618-622
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    • 1997
  • This study was carried out to investigate the effect of storage temperature (0, 5, $20^{\circ}C$) on chemical components of Korean kiwifruits. Moisture content decreased in $0^{\circ}C-,\;5^{\circ}C-stored$ samples and slightly increased in $20^{\circ}C-stored$ sample. Soluble solid content increased in $0^{\circ}C-,\;5^{\circ}C-stored$ samples and decreased in $20^{\circ}C-stored$ sample ranging from 11 to $14\;^{\circ}Brix$. pH and titratable acidity remained at the level of $3{\sim}3.5$ and $1{\sim}1.5$, respectively. The content of malic and quinic acid increased during storage at $0^{\circ}C$ and $5^{\circ}C$. In case of citric acid, the content increased up to 6th week and then decreased. Kiwifruits stored at $20^{\circ}C$ showed a changing pattern of organic acids similar to those stored at 0 and $5^{\circ}C$. Glucose, fructose and sucrose increased in $0^{\circ}C-,\;5^{\circ}C-stored$ samples except fructose at $5^{\circ}C$. In case of $20^{\circ}C-stored$ sample, sucrose increased up to 2∼3th week and then decreased.

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Effect of Medicinal Herbs' Extracts on the Growth of Lactic acid bacteria isolated from Kimchi and Fermentation of Kimchi (한약재 추출물이 김치 관련 유산균의 성장과 김치의 숙성에 미치는 효과)

  • Lee, Shin-Ho;Choi, Woo-Jeong
    • Korean Journal of Food Science and Technology
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    • v.30 no.3
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    • pp.624-629
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    • 1998
  • This studies were carried out to investigate antimicrobial activity of 35 kinds of medicinal herbs against lactic acid bacteria isolated from home-made Kimchi. The most isolated lactic acid bacteria were inhibited by ethanol extract of various medicinal herbs such as Schizandra chinensis (SC), Salvia miltiorrhiza (SM), Glycyrrhiza uralensis (GU), Lithospermum erythrorhizon (LE) and Sophrora flavescens AITON (SF). But Cnidium monnier, Pinus densiflora, Paeonia suffruticosa, Acanthopanax sessiliflorum and Rhus chinensis inhibited the growth of only a few isolated lactic acid bacteria. The pH of Kimchi containing 1% of medicinal herbs extracts such as SM, GU, LE and SF was higher than that of control during fermentation for 25 days at $10^{\circ}C$, respectively. Titratable acidity and viable cells of total bacteria and lactic acid bacteria of the Kimchi were lower than that of control during fermentation. The sensory quality (taste, flavor and overall acceptability) of SM, GU, and LE added Kimchi was similar to that of control at 10th day of fermentation. But Sophrora flavescens AITON added Kimchi decreased significantly its sensory quality compared with control(P<0.05).

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Comparison of Caries Activity of Some Children's Beverages Inoculated with Streptococcus mutans (Streptococcus mutans를 접종한 일부 어린이 음료의 우식활성능 비교)

  • Young-Nam PARK
    • Korean Journal of Clinical Laboratory Science
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    • v.55 no.3
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    • pp.195-202
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    • 2023
  • The caries activities of some commercially available children's beverages were measured to determine the risk of dental caries and provide basic data for preventing dental caries. For the experimental beverage, the beverages with the highest market share among carbonated beverages, fruit beverages, milk, and fermented milk products sold in the domestic market were selected. As a control, 0.25% glucose trypticase soy broth was prepared and used. The pH of the beverages, titrate acid and buffering capacity, and the acid production and vitality were measured over time after inoculating the beverages with Streptococcus mutans. The pH of children's beverages was the lowest in soda (2.61±0.02), and milk had the lowest in titratable acid (14.00±0.58). Fermented milk (80.33±3.64) had the highest buffering capacity, and carbonated beverage (9.40±1.06) had the lowest (P<0.05). Carbonated beverages (3 hr and 25 min) had the highest acid production, and milk (4 hr) had the lowest. In conclusion, thorough oral hygiene management is necessary after consuming children's beverages because they have a low pH promote high acid production of S. mutans.

Quality Characteristics of Brown Rice Takju by Different Nuruks (누룩 종류에 따른 현미 탁주의 품질특성)

  • Woo, Seung-Mi;Shin, Jin-Suk;Seong, Jong-Hwon;Yeo, Soo-Hwan;Choi, Ji-Ho;Kim, Tae-Young;Jeong, Yong-Jin
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.2
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    • pp.301-307
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    • 2010
  • This study evaluates quality of Nuruk, which is a source material of Takju, collected in Daegu and Gyeongbuk and investigates fermentation characteristics of Takju made of it. Totally 7 types of Nuruk were examined and their pH and titratable acidity were 5.4~5.9 and around 0.1%, respectively. Saccharifying activity was high in D, F, G, A and E Nuruk by recording over 300 mg%. Lactic acid bacteria count was the highest in G Nuruk with $3.78\times10^8$ and yeast and total microbe count recorded the highest levels, $3.78\times10^8$ and $3.47\times10^8$, respectively in B Nuruk. When quality characteristics of Takju made of each type of Nuruk were compared, alcohol content was the highest in G Nuruk by recording 19.0% and titratable acidity was 0.44~0.86% in all samples. Hunter's color, brown color and turbidity showed different levels according to types of Nuruk and all lactic acid bacteria, yeast and total microbe counts were the highest in A and E Nuruk. For alcohol components, E and G Nuruk showed high fusel oil content levels and methanol and fusel oil contents of all samples were suitable as standards, respectively. The total organic acid content was the highest in B Nuruk at about 4,000 mg% and it was 2,000 mg% and around 1,000 mg% in A, E, F and G Nuruk and C and D Nuruk, respectively. The content of total free amino acid was the highest in B Nuruk at 3,676 mg% and it was observed to be 1,890, 1,676 and 1,531 mg% in G, E and C Nuruk in that order, respectively. Sensory preference of subjects in their 20s was high overall in G and C Nuruk and that of those in their 40s was high in F and C Nuruk. From all of these results, the types of Nuruk largely affected quality and components of Takju and an appropriate method to consider useful purpose is needed.

Physicochemical Properties of Colostrum by Milking Time of Gyeonggi Province (경기지역의 착유회수에 따른 초유의 이화학적 특성)

  • Jeong, Seok-Geun;Ham, Jun-Sang;Kim, Dong-Hun;Ahn, Chong-Nam;Chae, Hyun-Seok;You, Young-Mo;Jang, Ae-Ra;Kwon, Il-Kyung;Lee, Seung-Gyu
    • Food Science of Animal Resources
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    • v.29 no.4
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    • pp.445-456
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    • 2009
  • Colostrum samples were collected from 36 dairy farms in Gyeonggi-do and one dairy farm in the National Institute of Animal Science (NIAS) for testing. Colostrum samples were analyzed for phisycochemicals (specific gravity, pH, titratable acidity), general components (fat, protein, lactose, total solid, solid non-fat (SNF)), fatty acids, amino acids, minerals, microflora, somatic cells, and Ig (Immunoglobulin). The first colostrum revealed the following data: fat contents were $6.16{\pm}2.39%$, proteins were $14.78{\pm}4.30%$, lactose $2.57{\pm}0.77%$, total solid $24.28{\pm}4.36%$, and SNF $18.12{\pm}4.08%$, whereas the 2nd (or $12^{th}$) colostrum revealed $5.56{\pm}1.76%$ fat, $3.46{\pm}0.41%$ proteins, $4.19{\pm}0.43%$ lactose, $13.90{\pm}1.76%$ total solid, and $8.34{\pm}0.81%$ SNF. Also, the first colostrum revealed the contents of major amino acids as 0.89% aspartic acid, 0.71% threonine, 0.86% serine, 1.75% glutamic acid, 0.64% valine, 0.95% leucine, 0.83% lysine, and 0.95% proline, and those in the 10th colostrum were 0.25% aspartic acid, 0.15% threonine, 0.19% serine, 0.59% glutamic acid, 0.19% valine, 0.35% leucine, 0.31% lysine, and 0.34% proine. Major amino acid contents rapidly decreased as milking times increased. In the first colostrum, the following mineral contents were observed: there were 2,168 ppm in Ca, 1,959 ppm in P, 914 ppm in K, 761 ppm in Na, 287 ppm in Mg, 1.7 ppm in Fe, 14.3 ppm in Zn, and 1.0 ppm in Cu; while in the 10th colostrum, the following ppm contents were 1,389 in Ca, 1,323 in P, 838 in K, 427 in Na, 131 in Mg, 1.0 in Fe, 4.7 in Zn, and 1.3 in Cu. The mineral contents in a colostrum rapidly decreased as milking times increased.

Effect of Squid and Octopus on the Quality Characteristics of Kimchi during Fermentation (문어와 오징어의 첨가량에 따른 배추김치의 숙성 중 품질특성에 미치는 영향)

  • Lee, Mi-Ai;Seo, Hye-Young;Yang, Ji-Hee;Jang, Mi-Soon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.42 no.12
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    • pp.2004-2011
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    • 2013
  • This study was carried out to investigate the chemical and microbiological properties of Kimchi containing different amounts of squid and octopus during fermentation at $4^{\circ}C$ for 56 days. Kimchi were assigned to one the of the following 7 treatment groups: CK (control Kimchi; no addition), SK-5 (added 5% of squid), SK-10 (added 10% of squid), SK-20 (added 20% of squid), OK-5 (added 5% of octopus), OK-10 (added 10% of octopus), and OK-20 (added 20% of octopus). The quality characteristics of CK and other treatments were determined by measuring the pH, titratable acidity, reducing sugar, volatile basic nitrogen (VBN), and microbial analysis. During fermentation, Kimchi containing squid and octopus had higher pH and lower acidity values than the CK group (P<0.05). The titratable acidity was increased in all treatment groups, whereas the reducing sugar content decreased gradually during fermentation. The reducing sugar contents were highest in the CK group. The VBN value increased in all treatment groups with increasing storage period, and the CK group had lower VBN value than the other treatment groups containing squid and octopus. The numbers of total bacteria and lactic acid bacteria rapidly increased up to the second week, and this slowly increased thereafter.

Quality Characteristics and Antioxidant Activity of Dioscorea bulbifera, under Various Oligosaccharide Pre-Soaking Condition (당 침지액 농도에 따른 건조 둥근 마의 품질 특성 및 항산화 효과)

  • Jo, Hye Min;Kim, Hee Young;Heo, Yoo Jeong;Song, Da Hye;Kim, Gyeong-Ji;Kim, In-Su;Yoon, Jin-A;Chung, Kang-Hyun;An, Jeong Hee
    • The Korean Journal of Food And Nutrition
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    • v.30 no.6
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    • pp.1176-1183
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    • 2017
  • This study was investigated the quality characteristics and antioxidant of dried Dioscorea bulbifera with various pre-soaking concentrations of oligosaccharide. Dioscorea bulbifera are prepared by additions of 0, 4, 6, 8 and 10% oligosaccharide solution, and dried at $50^{\circ}C$. The effects of pre-soaking percent of Dioscorea bulbifera slices were evaluated by the moisture, soluble solid, pH, titratable acidity, color, browning degree, texture, antioxidant activities and sensory test. According to the percent of pre-soaking oligosaccharide solution was increased, the moisture was increased but soluble solids and titratable acidity were decreased. With respect to the result of colors, Dioscorea bulbifera slices that underwent the 10% pre-soaked process (85.86%) were lighter than control (73.88%). However, the redness and yellowness scores were the lowest than control. The springiness and cohesiveness of texture showed no significant differences among all groups. Gumminess and chewiness of texture results were increased according to per-soaking concentration increase. Also the polyphenol, flavonoid and DPPH (${\alpha},{\alpha}$-diphenyl-${\beta}$-picrylhydrazyl) and ABTS [2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging activities were significantly increased with increasing immersion concentration. The Dioscorea bulbifera slices supplemented with 6% pre-soaking oligosaccharide solution treatment showed the highest total sensory score. The results of our study indicated that when pre-soaking oligosaccharide solution is used to immerse the Dioscorea bulbifera slice, it has browning inhibition and antioxidant effect.

Sensory Evaluation and Changes in Physiochemical Properties, and Microflora and Enzyme Activities of Pumpkin-added Kochujang (호박을 첨가하여 제조한 고추장의 숙성 중 성분 변화 및 관능적 특성)

  • Choo, Jong-Jae;Shin, Hyun-Ju
    • Korean Journal of Food Science and Technology
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    • v.32 no.4
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    • pp.851-859
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    • 2000
  • In the present study, changes in physicochemical and sensory properties, and microflora and enzyme activities, by addition of pumpkin (1, 2 and 5% pumpkin on the weight basis), of Sunchang sikhe kochujang, the most famous traditional kochujang, were investigated. Moisture content appeared to be reduced during fermentation, possibly due to exposure to the sun. Patterns of pH changes were rather complicated. pH of control kochujang was gradually reduced from the begining of fermentation up to 60 days of fermentation. Thereafter, it tended to be increased but again reduced after 90 days of fermentation. On the other hand, titratable acidity increased with fermentation reaching at the highest level at 90 day of fermentation and then slowly decreased. The addition of pumpkin induced a reduction in pH and an increase in titratable acidity, but this was due to organic acid contained in pumpkin itself. Contents of reducing sugar and amino nitrogen were increased by the addition of pumpkin in relation to the level of addition. Ethanol content was highly increased by the addition of pumpkin. Bacterial and yeast count, and activities of amylase and protease were not affected by the addition of pumpkin. Sensory evaluation test revealed that the addition of pumpkin improved sweet and savory taste, but color turned to be undesirable. However, none of tested parameters except color showed statistical significance.

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Influence of Addition of Membrane-Filtered Powder of Sunmul on the Quality Characteristics of Yogurt (막분리한 두부순물 농축분말첨가가 요구르트의 품질에 미치는 영향)

  • Jung, Jin-Young;Chung, Hai-Jung;Kim, Woo-Jung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.34 no.10
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    • pp.1579-1585
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    • 2005
  • The aim of this study was to propose utilization of tofu whey concentrates separated by ultrafiltration (UF) for yogurt production. The curd yogurt was prepared from whole milk added with skim milk Powder in which UF powder was substituted 0$\%$, 6.25$\%$, 12.5$\%$ or 25$\%$ for skim milk powder. The quality characteristics of yogurt in terms of pH, titratable acidity, viscosity, color and viable cell counts were evaluated. There were no significant differences in pH and titratable acidity between control (yogurt added with only skim milk powder) and yogurt added with UF powder after 24 hr of fermentation at 37$^{\circ}C$. Apparent viscosity of yogurt added with UF powder was lower (2,623 $\∼$ 3,189 cps) than that of the control yogurt (3,196 cps). Lightness and redness value of yogurt added with UF powder were not significantly different from control yogurt, while yellowness value increased as the amount of UF powder increased. Addition of UF powder stimulated the growth of lactic acid bacteria. Gas chromatographic analysis detected acetaldehyde, diacetyl, and organic acids, and more volatile compounds were detected in yogurt added with UF powder. Sensory analysis showed that yogurt added with UF powder were evaluated as acceptable as control yogurt. Therefore, UF powder could be substituted for skim milk powder without depressing yogurt qualify.