• Journal of Dairy Science and Biotechnology
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• 제34권2호
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• pp.75-82
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• 2016

Members of the genus Bifidobacterium are prevalent in the human colon and represent up to 90% of all bacteria in fecal samples of breast-fed infants, and 3~5% of adult fecal microbiota. Bifidobacteria produce organic acids, thus reducing the colon pH to a level inhibitory for pathogenic bacteria. They can also detoxify a number of toxic compounds and adhere to the colon mucosa, thus preventing the adherence of pathogens and induction of colon cancer. Recently, we identified a novel Bifidobacterium longum subsp. longum strain, KACC 91563, in a fecal sample of a Korean neonate, and demonstrated its functional properties. We showed that B. longum KACC 91563 alleviates food allergy through mast cell suppression and produces antioxidative and antihypertensive peptides by casein hydrolysis. Dairy products are considered as an ideal food system for the delivery of probiotic cultures to the human gastrointestinal tract. Cheese affords protection to probiotic microbes during gastric transit due to its relatively high pH, more solid consistency, higher fat content, and higher buffering capacity. Incorporation of B. longum KACC 91563 into cheese making is currently under study.

• Journal of Applied Biological Chemistry
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• 제58권3호
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• pp.247-251
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• 2015

In this study, a keratin-degrading bacterium was isolated from soil contaminated with feather waste. The isolated strain was identified as Chryseobacterium sp. P1-3 on the basis of the 16S rRNA gene sequence alignment. Chryseobacterium sp. P1-3 is currently used in various biotechnological applications (e.g., in the hydrolysis of poultry feathers). It hydrolyzed the feather meal within 2 days and possesses a high level of keratinase activity (98 U/mL). The keratinase, partially purified from this strain, prefers casein as a substrate and shows optimal activity at a temperature of $30^{\circ}C$ and at a pH of 8.0.

• Fisheries and Aquatic Sciences
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• 제15권1호
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• pp.83-89
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• 2012

Flavobacterium johnsoniae was isolated from farmed rainbow trout Oncorhynchus mykiss in Korea, and its biochemical and molecular characterization was determined. Yellow-pigmented bacterial colonies were isolated from 18 of 64 fish samples (28.1%) on trypticase soy agar plates, and their biochemical profiles were characterized by API 20E and API 20NE test kits. F. johnsoniae was identified by biochemical phenotyping of factors including rapid gliding motility, Gram-negative condition, oxidase- and catalase-positive status, Congo red absorption, nitrate reduction, ${\beta}$-galactosidase production, acid production from glucose, and gelatin and casein hydrolysis. PCR and subsequent sequencing of 16S rRNA confirmed that the yellow-pigmented colonies were most similar to F. johnsoniae. The alignment analysis of 16S rRNA sequences also showed that all 18 rainbow trout isolates had highly similar homologies (97-99% identity). One isolate was selected and named FjRt09. This isolate showed 98% homology with previously reported F. johnsoniae isolates, and in phylogenetic analysis was more closely grouped with F. johnsoniae than with F. psychrophilum, F. columnare, or F. branchiophilum. This is the first report on the occurrence and biochemical characterization of F. johnsoniae isolated from rainbow trout in Korea.

• 한국식품과학회지
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• 제9권2호
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• pp.97-105
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• 1977

1) 효모세포벽(酵母細胞壁) 용해활성(溶解活性)이 큰 미생물을 얻기 위하여 baker's yeast-peptone-bouillon agar 평판(平板)배지에서 투명하게 용해된 부위를 형성하는 균주(菌株)를 서울 및 경기지방의 토양 및 하수(下水)시료에서 156개 분리하였고 이들중 활성(活性)이 가장 큰 균주(菌株)로 K-42를 선발하여 Bacillus circulans로 동정(同定)하였다. 2) 균주(菌株) K-42에 의한 효모세포벽 용해효소의 생산을 보면 당류 첨가의 경우 배양 2일째에는 maltose>glucan>xylose>control의 순으로, 3일째에는 lactose>galactose>glucan>control의 순으로 나타났다. 무기 질소원의 경우는 배양2일째 ammonium acetat>sodium nitrate>control의 순으로, 3일째는 ammonium chloride>ammonium oxalate>control의 순으로 나타났으며 milk casein을 제외한 거의 모든 유기질소원은 배양 2일째 활성(活性)의 증가를 보였으나 3일째는 모두 감소하였다. 당류와 질소원의 배합첨가는 상승효과가 없었다. 3) 효소생산에 미치는 당류와 질소원의 첨가 효과는 배양기간 중 pH의 변화와 깊은 관계가 있었는 바 배양중 $pH\;7{\sim}8$을 계속 유지시켜 주면서 당류 또는 질소원을 첨가하면 높은 활성(活性)을 상당기간 계속 유지할 수 있었다. 4) K-42균주(菌株)가 분비(分泌)하는 세포벽(細胞壁) 용해효소의 작용최적(作用最適) 조건은 $pH\;7{\sim}8$, $60^{\circ}C$이었고 열처리(熱處理) 효모세포벽의 용해율은 65%이었다.

• 한국의류학회지
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• 제17권3호
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• pp.491-505
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• 1993

The influences of protease on the removal of various protein soils from cotton fabrics were studied. The human epidermal stratum corneum, hemoglobin and casein were used as protein soils. The soiled fabrics were denatured by steaming for 30 min. before washing and laundered using Terg-O-Tometer under washing conditions. The removal efficiency was evaluated by analysis of protein on the fabrics before and after washing by means of copper-Folin method. The relations between the removal and the characteristics of protease were discussed. Also the degradation of protein were examined by microscopy. The seperation of human epidermal stratum corneum after hydrolysis was examined by SDS-PAGE. The results obtained were as follow : 1. The protein from the soiled cotton fabric was removed effectively by adding protease. The removal of protein was increased in proportion to increasing of the enzyme concentration up to a certain point, but it began to decrease above the point. The removal effect was high in the order of casein>human epidermal stratum corneum>hemoglobin. Especially the protein was more effectively removed in ADS solution(pH 9.5) containing enzyme. 2. When protease was used with ADS. the removal of protein was efficiently showed in relatively short time(5~15min.) compared to using ADS only. It is due to the properties of this enzyme that reacts with very short time. 3. Even at low temperature the removal efficiency of enzyme was relatively higher compared with the activity of enzyme. The removal of protein soil was increased up to a maximum near $50^{\circ}C$, and then decreased. 4. The removal of protein by protease was improved with the increase of alkalinity in the pH range from 9.5 to 11.0 but it began to decrease above pH 11.0. 5. According to the increase of mechanical agitation, the removal effect was increased. But the removal efficiency of protease was more effective compared with the agitation in detergency. 6. According to the SDS-PAGE separation and micrograph it was confirmed that the human epidermal corneum was effectively hydrolysed by the enzyme added. So the fragments of protein were removed more efficiently by means of the interfacial reaction of AOS.

• 한국식품영양과학회지
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• 제16권3호
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• pp.11-20
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• 1987

우육(牛肉) 조리시(調理時) 첨가(添加)되는 향신료(香辛料) 등이 우육(牛肉)의 연화(軟化)에 미치는 영향(影響)을 알아보기 위하여 향신료(香辛料) 자체(自體)의 단백질(蛋白質) 가수분해능(加水分解能)의 유무(有無)와 이에 따른 연화효과(軟化效果)를 연육소(軟肉素) 및 연육기(軟肉器)에 의한 연육효과(軟化效果)와 비교(比較) 검토(檢討)하였다. 1. Casein을 기질(基質)로 하여 향신료(香辛料)의 단백질(蛋白質) 분해효소능(分解酵素能)의 유무(有無)를 실험(實驗)한 결과(結果), 모든 시료(試料)에서 단백질분해효소능(蛋白質分解酵素能)이 확인(確認)되었으며 각(各) 시료(試料)의 단백질(蛋白質) 분해정도(分解精度)는 마늘, 무우, 생강 그리고 양파의 순(順)으로 컸다. 2. 조직학적(組織學的) 특성검사(特性檢査)에서 연육소처리(軟肉素處理)를 한 조직(組織)은 전반적(全般的)으로 collagen 및 elastic fiber, 근계육(筋繼維) 등이 분해(分解)되는 정도(程度)가 현저(顯著)하였으며, 연육기처리(軟肉器處理) 조직(組織)은 collagen 및 elastic fiber, 근계육(筋繼維) 등이 절단(切斷)되어 조직(組織)이 붕괴(崩壞)되었다. 또한 향신료(香辛料)를 처리(處理_한 조직(組織)도 단백질(蛋白質) 가수분해효소능(加水分酵素能)에 의해 collagen, elastic fiber 및 근계육(筋繼維)가 부분적(部分的)으로 분해(分解)되었다. 3. 처리육(處理肉)의 유연성(柔軟性)에 대한 관능검사(官能檢査)의 결과(結果), F-value가 11 27로 4가지 시료(試料)사이에 1% 수준에서 유의성(有意性)이 인정(認定)되었으며, 시료간(試料間) 유의성(有意性)의 차이(差異)에 있어서 향신료처리(香卒料處理) 쇠고기는 5% 수준(水準)에서 처리(處理)하지 않은 쇠고기와의 간(間)에 유의성(有意性)이 인정(認定)되었다.

• Journal of Dairy Science and Biotechnology
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• 제32권1호
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• pp.7-16
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• 2014

최근 성인병 중에서 가장 높은 빈도로 발병하는 것이 고혈압인데, 이 고혈압의 예방하기 위해서 가장 손쉽게 일상적으로 섭취할 수 있는 것이 바로 우유의 성분인 카제인염이다. 일반적으로 우유 펩타이드는 혈압조절자인 ACE를 방해함으로써 혈압을 줄여주는 항고혈압 효과와 관련이 있으며, 또한 혈액의 혈소판 응집을 저해해 심근경색이나 뇌경색의 원인인 혈전을 방지한다라고 알려져 있다. 따라서 이러한 기능을 가지고 있는 우유의 카제인염을 다양한 단백질가수분해 효소로 처리하여 가수분해 시간에 따른 특성 그리고 ACE 저해효과가 높은 가수분해물을 제조하기 위해서 대표적인 막여과 방법인 한외여과법이 이용되고 있는 것을 살펴보았다. 향후 가수분해물들의 (1) 항산화 효과, 세포독성 및 용해성, 기포성 등이 더 향상될 수 있도록 효소선발과 효소처리에 대한 폭 넓은 조사와 연구, (2) 고품질 대량생산법 확립, 그리고 (3) 건강기능성식품으로의 산업화 이용이 가능하도록 지속적인 기초 연구가 신속히 진행되어야 할 것이다.

• Journal of Microbiology
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• 제41권3호
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• pp.207-211
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• 2003

Extracellular protease, from Aeromonas hydrophila Ni 39, was purified 16.7-fold to electrophoretic homogeneity with an overall yield of 19.9％, through a purification procedure of acetone precipitation, and Q Sepharose and Sephacryl S-200 chromatographies. The isoelectric point of the enzyme was 6.0 and the molecular mass, as determined by Sephacryl S-200 HR chromatography, was found to be about 102 kDa. SDS/PAGE revealed that the enzyme consisted of two subunits, with molecular masses of 65.9 kDa. Under standard assay conditions, the apparent $K_{m}$ value of the enzyme toward casein was 0.32 mg/ml. About 90％ of the proteolytic activity remained after heating at 60$^{\circ}C$ for 30 min. The highest rate of azocasein hydrolysis for the enzyme was reached at 60$^{\circ}C$, and the optimum pH of the enzyme was 9.0. The enzyme was inhibited by the serine protease inhibitor, phenylmethylsulfonyl fluoride (PMSF), by about 87.9％, but not by E64, EDTA, pepstatin or 1,10-phenanthroline. The enzyme activity was inhibited slightly by Ca$\^$2＋/, Mg$\^$2＋/ and Zn/supb 2＋/ ions.

• Journal of Nutrition and Health
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• 제30권1호
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• pp.40-47
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• 1997

Dietary peptides have recently received attention regarding their beneficial effects on nutrient metabolism since the caseinphosphoptides obtained from casein hydrolysate are generally believed to enhance the intestinal absorption of Ca. The two experiments were conducted to investigate the effects of various hydrolyzed fractions of gluten on Ca bioavailability. The gluten hydrolysate of dietary components was produced by enzymatic hydrolysis of gluten whereas gluten hydrolysate supernationt and its precipiate resulted from centrifugation. In experiment I, the rats were for 4 weeks fed the 4 kinds of diets containing same amount of nitrogen and calories and diffeing only in the forms of nitrogen sources. The diets were gluten (G), gluten hydrolysat(GH), gluten hydrolysate supernatant(GHS) and gluten hydrolysate precipitatie(GHP). Determination was made for the body weight gain, serum Ca concentration, Ca solubility in small intestinal contents, bone weight, length and stength, bone ash and Ca content, and Ca balance, respectively. No significant difference was noticed as regards growth, serum Ca, and bone dimension and Ca content among rat groups. More significant increase was observed with regard to Ca absorption and intestinal solubility in the rats receiving the GH or GHS diet which containe crude gluten peptides, than in those subjected to G or GHP diet. In experiment II, in vitro determination for Ca solubility was made to ascertain the mechanism responsible for the effects of gluten peptides on Ca absorption. The 10mM Ca in potassium phosphate buffer solution(pH 7.0) incubated for 3 hours at 37$^{\circ}C$ by the GHS fraction, was observed to be capable of increasing the Ca solubility at 5-25mg/ml concentration of gluten peptides. These observations suggest that the gluten peptides from gluten hydrolysate may enhance the Ca absorption efficiency by increasing the solubility of Ca in small intestine.

• 한국수산과학회지
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• 제53권1호
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• pp.112-122
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• 2020

This study investigated some enzymatic properties and bitterness improvement of an aminopeptidase retentate fraction (ARF) from common squid Todarodes pacificus hepatopancreas extract (HPE), obtained by ultrafiltration with a 10 kDa molecular weight cut off membrane. Endoprotease and aminopeptidase (AP) activity, and the purity of the ARF (>10 kDa) increased by 6.69-18.11 U/mg and 1.5-2.6 fold, respectively, compared to HPE (2.63-9.37 U/mg). The AP activity toward LeuPNA was stable at 20-55℃ and pH 5-9, but decreased slightly with increasing concentration of NaCl in the reaction mixture. The ARF was the most active MetPNA and preferentially hydrolyzed Glu, Leu and AlaPNA. The bitterness tryptic casein hydrolysates (BTCHs) were treated with ARF, and the bitterness of ARF-BTCHs significantly decreased with increasing amounts of released amino acids Ala, Val, Met, Ile and Leu, which show strong correlations with bitterness. Therefore, the ARF of T. pacificus HPE obtained by ultrafiltration may have a considerable potential for application in protein hydrolysis and appears to be ideally suited to the purpose of lowing bitterness in protein hydrolysates.