• 한국식품영양과학회지
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• 제27권6호
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• pp.1117-1124
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• 1998

Chymosin was purified from commercial rennet with DEAE Sepharose CL 6B and immobilized on CeliteTM using glutaraldehyde. Whole casein from fresh raw milk was hydrolyzed by immobilized chymosin and total CMP was isolated by trichloroacetic acid(TCA) and ultrafiltration, and characterized. The amount of chymosin purified from 15g commercial rennet by DEAE Sepharose CL 6B was 0.16g and 18mg of chymosin was immobilized on 1g of CeliteTM by 5% glutaraldehyde. Immobilized chy mosin hydrolyzed most of casein on whole casein within 2 hours to leave para casein and casei nomacropeptide(CMP). The total CMP isolated from 10g of whole casein hydrolyzate by TCA and ultrafiltration was 0.4g and 0.1g, respectively. Results of electrophoresis, amount of sialic acid, com position of amino acid and ratio of A280 to A214 showed that total CMP by TCA was purer and had more CMP without carbohydrate than one by ultrafiltration. CMP isolated from total CMP by 12% TCA precipitation was 50% of total CMP and most of caseinoglycopeptide(CGP) was removed from total CMP, indicating less amount of sialic acid in CMP than in total CMP.

• Asian-Australasian Journal of Animal Sciences
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• 제15권4호
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• pp.602-609
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• 2002

Lao-chao is a traditional Chinese fermented rice product with a sweet and fruity flavor, containing high levels of glucose, a little alcohol and milk-clotting characteristics. In order to optimize commercial production of lao-chao, Rhizopus javanicus and Saccharomyces cerevisiae were selected as the mold and yeast starter, respectively. A commercial mixed starter (chiu-yao) was used as control. Fermentation of the experimental combination revealed a sharp drop in pH (to 4.5) on the fourth day, remaining constant thereafter. Content of reducing sugars gradually decreased throughout the entire fermentation period. Of the free amino acids, higher quantities of alanine, leucine, proline, glutamic acid, glutamine and $NH_3$ were noted. For sugars, glucose revealed the highest concentration, while organic acid levels, including those for oxalic, lactic, citric and pyroglutamic acid, increased throughout the fermentation period. Twenty-one compounds were identified by gas chromatography from aroma concentrates of the lao-chao culture filtrate, prepared using the headspace method. For the flavor components, higher quantities of ethanol, fusel oil and ester were determined in both culture filtrates. In regard to the evaluation of yogurt-like product, there were significant differences in alcoholic smell, texture and curd firmness.

• 한국축산식품학회지
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• 제42권6호
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• pp.1009-1019
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• 2022

In recent years, biocontrol of foodborne pathogens has become a concern in the food industry, owing to safety issues. Listeria monocytogenes is one of the foodborne pathogens that causes listeriosis. The major concern in the control of L. monocytogenes is its viability as it can survive in a wide range of environments. The purpose of this study was to isolate lactic acid bacteria with antimicrobial activity, evaluate their applicability as a cheese starter, and evaluate their inhibitory effects on L. monocytogenes. Lactococcus lactis strain with antibacterial activity was isolated from raw milk. The isolated strain was a low acidifier, making it a suitable candidate as an adjunct starter culture. The commercial starter culture TCC-3 was used as a primary starter in this study. Fresh cheese was produced using TCC-3 and L. lactis CAU2013 at a laboratory scale. Growth of L. monocytogenes (5 Log CFU/g) in the cheese inoculated with it was monitored during the storage at 4℃ and 10℃ for 5 days. The count of L. monocytogenes was 1 Log unit lower in the cheese produced using the lactic acid bacteria strain compared to that in the cheese produced using the commercial starter. The use of bacteriocin-producing lactic acid bacteria as a starter culture efficiently inhibited the growth of L. monocytogenes. Therefore, L. lactis can be used as a protective adjunct starter culture for cheese production and can improve the safety of the product leading to an increase in its shelf-life.

• 한국식품위생안전성학회지
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• 제13권4호
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• pp.430-440
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• 1998

식육류에서의 오염지표세균의 분포를 보면 돈육에서는 일반세균 19/g, 대장균군 1.8/g, 저온세균 15/g, 종석영양세균 12/g, 분원성연쇄상구균 6.2/100 g, 슈도모나스 13/100 g이었으며, 내열성세균 및 포도상구균은 검출되지 않았다. 우육에서는 일반세균수 $1.3{\times}10^{2}/g$, 대잔균군 5.2/g, 저온세균 $1.4{\times}10^{2}/g$, 종속영양세균 28/g, 포도상구균 1.2/g, 분원성연쇄상구균 9.5/100 g, 슈도모나스균 1.9/100 g이었으며 내열성세균은 검출되지 않았다. 계육은 일반세균수 $8.8{\times}10^{3}/g$, 대장균군 53/g, 저온 세균 $4.6{\times}10^{3}/g,\;종속영양세균\;4.7{\times}10^{3}/g$ 분원성연쇄상구균 9.9/100g, 슈모나스균 1.5/100 g이었으며, 내열성세균 및 포도상구균은 검출되지 않았다. 우유에서는 일반세균 $4.7{\times}10^{3}/m;\l,\;저온세균\;1.2{\times}10^{2}/ml,\;종속영양세균\;4.2{\times}10^{2}/ml$이었으며, 대장균군, 내열성세균, 포도상구균, 분원성연쇄상구균 및 슈도모나스균은 검출되지 않았다. 치즈에서는 일반세균 3.2/g, 저온세균 2.3/g, 종속영양세균 1.6/g, 포도상구균 1/g, 분원성연쇄상구균 9.1/100g 이었으며, 대장균군, 저온세균, 종속영양세균, 포도상구균 및 슈도모나스균은 검출되지 않았다. 치즈에서는 일반세균 3.2g, 저온세균 2.3/g, 종속영양배균 1.6/g, 포도 상구균 1/g, 분원성연쇄상구균 9/100 g이었으며, 대장균군, 내열성세균 및 슈도모나스균은 검출되지 않았다. 발효유에서는 유산균의 영향을 받아 일반세균수 $1{\times}10^{7}/ml,\;내열성세균\,1.0{\times}10^{6}/ml,\;분원성연쇄상구균\;2.4{\times}10^3/100\,m;,\;유산균수\;3.2{\times}10^{15}/ml$이었으며, 대장균군, 저온세균, 종속영양세균, 포도상구균 및 슈도모나스균은 검출되지 않았다. 그 밖의 햄, 소시지, 버터, 계란, 메추리알에서는 오렴지표세균이 모두 검출되지 않았다. 시판동물성 식품을 $10^{\circ}C,\;20^{\circ}C\;30^{\circ}C$에서 보관하면서 저장기간별로 오염지표세균의 변화를 조사한 결과 식육류는 $10^{\circ}C$에서 보존할 경우 일반세균, 대장균군, 저온세균 및 종속영양세균은 시간이 지날수록 급격히 균수가 증가하였으나 내열성세균, 포도상구균, 분별성연쇄상구균 및 슈도모나스균은 거의 변화하지 않았다. $20^{\circ}C$에서 보존할 경우 일반세균, 대장균군, 저온세균, 종속영양세균 및 분변성연쇄상구균은 7일 보존시 가장 높은 균수를 나타내었으며, 내열성세균, 포도상구균 및 슈도모나스균은 약간 증가하였다. $30^{\circ}C$에서 보존할 경우에는 3일부터 7일 사이에 가장 높은 균수를 나타내었고, 7일부터 급격히 감소하는 경향을 나타내었다. 식육가공품은 $10^{\circ}C$에서 보존할 경우 17일 보존시 $10^{1}/g$ 수준까지 증가하였을 뿐이었고, $20^{\circ}C$에서 보존할 경우 일반세균, 저온세균 및 종속영양 세균이 $10^{5}/g$ 수준정도 증가하였으며, 나머지 지표세균은 거의 변화가 없었다. $30^{\circ}C$에서 보존할 경우 $20^{\circ}C보다\;10^{2}/g$ 수준 더 증가하는 경향을 나타내었을 뿐이었다. 우유류는 저온 살균처리에 의해 일반세균, 저온 세균 및 종속영양세균이 $10^{\circ}C\;보존시\;10^{4}/ml$ 수준까지 증가하였을 뿐 대장장균군, 포도상구균, 분변성연쇄상구균 및 슈도모나스균은 전혀 검출도지 않았다. $20^{\circ}C와\;30^{\circ}C$에서는 빠른 속도로 균수가 증가한 후 일정한 상태를 유지하였다.

• Journal of Dairy Science and Biotechnology
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• 제36권3호
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• pp.178-185
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• 2018

Kefir, which originates in the Caucasian mountains, is a cultured milk beverage produced by a combination of acidic and alcoholic fermentation. Kefir products are commonly used as food vehicles to deliver health-promoting materials including kefran and lactic acid bacteria to consumers. The aim of this study was to develop a freeze-dried starter culture without yeast and assess the suitability of kefir-like dairy products for the growth of lactic acid bacteria and the acidification of milk. Pasteurized whole milk (SNF 8.5%) stored at $25^{\circ}C$ was aseptically inoculated with starter cultures (0.002% w/v); it was kept at $25^{\circ}C$ until the pH attained a value of 4.6. Ten grams of the kefir-like product sample was diluted with 90 mL of 0.15% peptone water diluent in a milk dilution bottle, followed by uniform mixing for 1 min. Viable cells of Lactobacillus species were enumerated on modified-MRS agar (pH 5.2), with incubation at $37^{\circ}C$ for 48 h. Viable cells of Lactococcus species were enumerated on M17-lactose agar, with incubation at $32^{\circ}C$ for 48 h. The pH attained a value of 4.6 after fermentation for 9 h 30 min (Starter 1), 9 h 45 min (Starter 2), and 12 h (Starter 3). The viable cell count of Lactobacillus sp. and Lactococcus sp. was initially $10^5{\sim}10^6CFU/g$; it increased significantly to $10^9CFU/g$ after 12 h of incubation. During the storage of the kefir-like products at $4^{\circ}C$ for 1 4 days, the total viable cell numbers were unchanged, but the pH decreased slightly. The consistency of the kefir products increased gradually during the storage. The organoleptic properties of the kefir products fermented using the new starter culture are more desirable than those of commercial kefir. These results suggest that the newly developed starter culture without yeast could be suitable for kefir fermentation.

• 한국식품영양과학회지
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• 제45권6호
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• pp.889-893
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• 2016

본 연구에서는 고압처리(high pressure processing) 한 원유를 이용하여 발효유를 제조하고, 발효특성 및 저장 기간 물리 화학적 특성의 변화를 살펴보았다. 고압처리 한 원유를 이용하여 발효유 제조 시 발효 초반에 유산균이 급격히 증식 됨을 확인하였으나, 발효 완료 후 총 유산균 수는 대조군과 크게 차이가 나지 않았다. 저장 기간 중 실험군과 대조군 모두 유산균 수가 서서히 감소하는 경향을 나타내었다. 또한 산도 및 pH는 각 군 모두 정상적인 발효유의 범위를 나타내었다. 각 군의 점도를 대조해 본 결과 대조군이 실험군보다 점도가 높게 나타났으나, syneresis는 450 MPa 처리군이 대조군보다 유의적으로 적게 발생한 것으로 나타났다(P<0.05). 따라서 적절한 압력을 이용한 원유의 고압처리는 발효유의 물성을 개선하는 데 효과가 있다고 할 수 있으며, 이 분야에 관한 연구가 좀 더 이루어져야 할 필요가 있다.

• 한국축산식품학회지
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• 제35권2호
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• pp.189-196
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• 2015

The aim of this study was to manufacture functional high protein fermented beverage, using whey protein concentrate (WPC) and Lactobacillus plantarum DK211 isolated from kimchi, and to evaluate the physicochemical, functional, and sensory properties of the resulting product. The fermented whey beverage (FWB) was formulated with whey protein concentrate 80 (WPC 80), skim milk powder, and sucrose; and fermented with Lactobacillus plantarum DK211 as single, or mixed with Lactococcus lactis R704, a commercial starter culture. The pH, titratable acidity, and viable cell counts during fermentation and storage were evaluated. It was found that the mixed culture showed faster acid development than the single culture. The resulting FWB had high protein (9%) and low fat content (0.2%). Increased viscosity, and antioxidant and antimicrobial activity were observed after fermentation. A viable cell count of 10⁹ CFU/mL in FWB was achieved within 10 h fermentation, and it remained throughout storage at 15℃ for 28 d. Sensory analysis was also conducted, and compared to that of a commercial protein drink. The sensory scores of FWB were similar to those of the commercial protein drink in most attributes, except sourness. The sourness was highly related with the high lactic acid content produced during fermentation. The results showed that WPC and vegetable origin lactic acid bacteria isolated from kimchi might be used for the development of a high protein fermented beverage, with improved functionality and organoleptic properties.

• 한국식품과학회지
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• 제25권3호
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• pp.258-263
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• 1993

팽화 미분을 우유에 첨가하여 상업용 젖산균으로 호상요구르트를 제조하여 이의 품질 특성과 저장중 변화를 관찰하였다. 팽화미 제조용 쌀의 수분 함량은 14% 내외가 팽화에 가장 적당하였고 팽화 미분을 요구르트 제조시 첨가할 때 첨가량이 많아짐에 따라 lightness는 떨어지고 적색도 및 황색도는 증가하면서 점도는 크게 상승하였다. 관능평가 결과 4%까지는 표준구와 차이가 없었고 각종 상업용 젖산균은 요구르트 제조시 pH, 산도 및 점도에는 차이가 나타났으나 관능적 품질에는 영향을 주지 못하였다. 팽화 미분을 첨가한 요구르트를 $5^{\circ}C$에 저장하는 경우 pH는 계속 하강하고 산도는 증가하면서 점도는 상승하는 현상을 보였고 젖산균은 저장 16일까지 $10^8$ 이상을 유지하고 있었다. 상업용 요구르트와 관능검사로 품질을 비교한 결과 맛, 향, 조직에서 차이가 있으나 조직의 개선과 향 보완으로 새로운 제품 제조 가능성을 보였다.

• Journal of Microbiology and Biotechnology
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• 제4권2호
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• pp.151-154
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• 1994

Lactobacillus acidophilus KFRI 233, a strain isolated from human, was selected as a candidate for probiotics due to its excellent growth in MRS broth where no special anaerobic condition is required. Both simultaneous and deferred agar diffusion assays exhibited Lb. acidophilus KFRI 233 to possess an antagonistic effect against Clostridium perfringens. Its antagonistic effect was pH dependent Associative culture of KFRI 233 and Cl. perfringens in broth resulted in maximum 94.04% inhibition of Cl. perfringens. $\beta$-Galactosidase activity of KFRI 233 was higher than other tested strains that are sold as commercial probiotics. Survival of KFRI 233 in pasteurized skim milk (4$^{\circ}C$) and Sherbet mix (-15$^{\circ}C$) after 7 days of storage were 71.9 and 105.5%, respectively.

• Asian-Australasian Journal of Animal Sciences
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• 제12권1호
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• pp.68-76
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• 1999

A formal survey was carried out in Nharira-Lancashire areas located in Chivhu to assess the calf rearing systems practiced in smallholder dairy farming areas of Zimbabwe. A total of 47 farmers, collectively owning 305 cows and 194 calves of various breeds, participated in the survey. All the farmers allowed their calves to suckle their dams all day to obtain colostrum. The colostrums intake period was significantly (p < 0.05) shorter (5.2 vs 4.1 days) in the small scale commercial area (SSCA) compared to communal area (CA). Milk was first sold to the Nharira-Lancashire Milk Centre a day after the colostrum intake period ended. Most of the CA (91.3%) and SSCA (77.8%) farmers penned their cows and calves together at night during the colostrum intake period. Thereafter the calves were penned separate from their dams. After colostrum intake, two types of calf suckling systems were practised; twice a day suckling and twice a day then changed to once a day suckling. In both systems, suckling was allowed for 30 minutes after the cows had been hand milked. There was no significant (p < 0.05) difference in the mean weaning age of calves between the CA and SSCA (5.8 vs 5.4 months). The most common weaning method was through separation of the calves from the dams. The limitaitions to calf production in Chivhu were the prohibitively high costs of calf meals, poor feed resources during the dry season, a general lack of knowledge on calf rearing diseases and inappropriate calf housing.