• Applied Biological Chemistry
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• 제36권5호
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• pp.352-357
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• 1993

S.G.Y.배지(skim milk, glucose, yeast extract)와 S.M.W.배지(skim milk whey). 배지에 P. freudenreichii KFCC 31227과 L. acidophilus KFCC 32825를 단독 또는 혼합배양 후, 두 균주의 생육 및 유기산 생성에 미치는 발효여액의 영향과 당의 변화 및 이용 효과를 검토한 결과, 자신의 발효여액보다는 상대편의 발효여액에서 그리고 단독배양보다는 혼합배양에서 생육이나 산 생성의 효과가 촉진되었으며, 배지중의 glucose 및 lactose 의 이용효과를 보면 P. freudenreich-ii KFCC 31227 단독 배양시는 lactose 를, L. acdophilus KFCC 32825 단독배양시는 glucose를 생육이나 산 생성에 더 잘 이용하였다. 또한 두 균주의 혼합배양시에는 단독배양에 비해 발효에 glucose 나 lactose 를 이용하는 시간이 더욱 단축되는 결과로 나타났으며, 이것은 혼합배양시 두 균주의 상호작용에 의한 synergism 효과에 기인된 것으로 생각된다.

• Food Science and Biotechnology
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• 제16권1호
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• pp.83-89
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• 2007

In our study, lactic acid bacteria (LAB)-fermented whey solutions were applied in the soybean soaking process to minimize bacterial contamination and to enrich the biologically functional components of isoflavone and $\gamma$-aminobutyric acid (GABA). Among the 11 LAB tested, Bifidobacteria infantis and a mixed culture (Lactobacillus acidophilus, Bifidobacteria lactis, and Streptococcus thermophilus; ABT-3) displaying the greatest $\beta$-glucosidase activity were selected to produce improved biologically functional soybean preparations. In the soybean soaking processing (without water spraying), the LAB-cultured 10% whey solution was used to soak and to ferment the soybeans and the fermented soybeans were finally dried by heat-blowing at $55^{\circ}C$. The processing conditions used in this study demonstrated that the final soybean product had a reduced contamination by aerobic and coliform bacteria, compared to raw soybeans, likely due to the decrease in pH during LAB fermentation. The aglycone content of the isoflavone increased up to 44.6 mg per 100 g of dried soybean by the processing method, or approximately 8-9 times as much as their initial content. The GABA contents in the processed samples increased as the processing time of soaking-fermentation proceeded as well. The soybean sample that fermented by ABT-3 culture for 24 hr showed the greatest increase in GABA content (23.95 to 97.79 mg/100 g), probably as a result of the activity of glutamate decarboxylases (GAD) released from the soybean or produced by LAB during the soaking process.

• 한국축산식품학회지
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• 제33권5호
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• pp.565-571
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• 2013

An enzyme ${\beta}$-galactosidase or ${\beta}$-galactohydrolase [EC3.2.1.23], commonly called lactase, mediates galacto-oligosaccharide (GOS) synthesis under conditions of high substrate concentrations. Also, lactase hydrolyzes ${\beta}$($1{\rightarrow}4$) lactose into glucose and galactose, the latter is successively transferred to free lactose to make various oligosaccharides via transgalactosylation. GOS is non-digestible to human digestive enzymes and has been used as a functional prebiotics. Among the 24 lactic acid bacteria (LAB) strains used, Lactobacillus paracasei YSM0308 was selected based on its exhibition of the highest ${\beta}$-galactoside hydrolysis activity, and the crude lactase was prepared for examination of reaction conditions to affect the GOS synthesis. Lactase activity was measured with a spectrophotometer using ONPG (o-nitropheyl ${\beta}$-D-galactopyranoside) method. Lactase activity was not detected in the culture supernatant and was mostly present in the cell pellet after centrifugation. Activity of the crude lactase preparation ranges from102 to 1,053 units/mL, with the highest activity determined for L. paracasei YSM0308. Optimal conditions for GOS synthesis are as follows: concentration of whey powder, pH, temperature, and time were 30%, pH 6.5-7.0, $30^{\circ}C$, and 4 h, respectively. The final GOS concentration was 19.41% (w/v) by the crude YSM0308 lactase, which was obtained from strain YSM0308 grown in the 10% (w/v) reconstituted whey-based medium.

• 한국식품과학회지
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• 제24권4호
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• pp.311-314
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• 1992

역삼투 방법을 이용한 두부순물의 정화시 역삼투 잔사의 활용 가능성을 검토하기 위해 두부순물 농축물의 성분 특성 및 분리 단백질의 기능성을 조사하였다. 두부순물의 역삼투 잔사 농축물에는 자당, 라피노오스 및 스타치오스가 건물 중으로 각각 32.59%, 4.76% 및 9.99% 함유되어 있었고, 무기물중 칼륨이 5.23%로 회분의 42.7%를 점하였다. 또한 조단백질 함량은 18.69%이었으며 아미노산 조성 및 전기영동상의 sub-unit 양상은 분리 콩단백질과 다소 차이를 보였다. 한편 두부순물로부터 분리한 단백질의 기능성중 pH에 따른 용해도는 분리 콩단백질에 비해 전반적으로 다소 높은 값을, 유화능과 유화안정성 및 점도는 분리 콩단백질보다 비교적 낮은 값을 나타냈다.

• Asian-Australasian Journal of Animal Sciences
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• 제29권7호
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• pp.1022-1028
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• 2016

Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat ($6.82%{\pm}0.04%$), solid-not-fat ($11.24%{\pm}0.02%$), total solids ($18.05%{\pm}0.05%$), protein ($5.15%{\pm}0.06%$) and casein ($3.87%{\pm}0.04%$) contents followed by buffalo milk. Maximum whey proteins were observed in camel milk ($0.80%{\pm}0.03%$), buffalo ($0.68%{\pm}0.02%$) and sheep ($0.66%{\pm}0.02%$) milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82), cow (r = 0.88), sheep (r = 0.86) and goat milk (r = 0.98). The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow ($108{\pm}2.3mg/g$), camel ($96{\pm}2.2mg/g$) and buffalo ($90{\pm}2.4mg/g$) milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products.

• Journal of Dairy Science and Biotechnology
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• 제35권4호
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• pp.270-285
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• 2017

Among milk proteins, caseins are not subjected to chemical changes during heat treatment of milk; however, whey proteins are partially denatured following heat treatment. The degree of whey protein denaturation by heat treatment is decreased in the order of high temperature short time (HTST) > low temperature long time (LTLT) > direct-ultra-high temperature (UHT) > indirect-UHT. As a result of heat treatment, several changes, including variations in milk nitrogen, interactions between beta-lactoglobulin and k-casein, variations in calcium sulfate and casein micelle size, and delay of milk coagulation by chymosin action, were observed. Lysine, an important essential amino acid found in milk, was partially inactivated during heat treatment. Therefore, the available amount of lysine decreased slightly (1~4% decrease) after heat treatment, However, the influence of heat treatment on the nutritional value of milk was negligible. Nutritional value and nitrogen balance did not differ significantly between UHT and LTLT in milk. In conclusion, our results showed that heat treatment of milk did not alter protein quality. Whey proteins denatured to a limited extent during the heat treatment process, and the nutritional value and protein quality were unaffected by heat treatment.

• 한국축산식품학회지
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• 제43권4호
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• pp.594-611
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• 2023

Whey protein (WP) has nutritional value, but the presence of β-lactoglobulin (β-LG) and α-lactalbumin (α-LA) cause allergic reactions. In this study, hypoallergenic whey protein hydrolyate (HWPH) was prepared by decomposing β-LG and α-LA of WP using exo- and endo-type proteases. The enzyme mixing ratio and reaction conditions were optimized using response surface methodology (RSM). Degradation of α-LA and β-LG was confirmed through gel electrophoresis, and digestion, and absorption rate, and immunostimulatory response were measured using in vitro and in vivo systems. Through RSM analysis, the optimal hydrolysis conditions for degradation of α-LA and β-LG included a 1:1 mixture of Alcalase and Prozyme reacted for 10 h at a 1.0% enzyme concentration relative to substrate. The molecular weight of HWPH was <5 kDa, and leucine was the prominent free amino acid. Both in vitro and in vivo tests showed that digestibility and intestinal permeability were higher in HWPH than in WP. In BALB/c mice, as compared to WP, HWPH reduced allergic reactions by inducing elevated Type 1/Type 2 helper T cell ratio in the blood, splenocytes, and small intestine. Thus, HWPH may be utilized in a variety of low allergenicity products intended for infants, adults, and the elderly.

• 한국축산식품학회지
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• 제43권3호
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• pp.540-551
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• 2023

Milk protein concentrate (MPC) is widely used to enhance the stability and texture of fermented dairy products. However, most research has focused on yogurt products, and the effects of MPC on sour cream characteristics remain unknown. Therefore, we investigated the effects of different MPC levels (0%, 1%, 2%, and 3% w/w) on the rheological, physicochemical, microbiological, and aroma characteristics of sour creams in this study. We found that MPC supplementation stimulated the growth of lactic acid bacteria (LAB) in sour creams, resulting in higher acidity than that in the control sample due to the lactic acid produced by LAB. Three aroma compounds, acetaldehyde, diacetyl, and acetoin, were detected in all sour cream samples. All sour creams showed shear-thinning behavior (n=0.41-0.50), and the addition of MPC led to an increase in the rheological parameters (η_a,50, K, G', and G"). In particular, sour cream with 3% MPC showed the best elastic property owing to the interaction between denatured whey protein and caseins. In addition, these protein interactions resulted in the formation of a gel network, which enhanced the water-holding capacity and improved the whey separation. These findings revealed that MPC can be used as a supplementary protein to improve the rheological and physicochemical characteristics of sour cream.

• Journal of Dairy Science and Biotechnology
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• 제31권2호
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• pp.93-98
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• 2013

For purposes of substantiation of organizing measures on industrial processing of goat's and sheep's milk in Mongolia and the production of dairy products we have conducted the studied physico-chemical characteristics of the Mongolian goat's and sheep's milks especially to recognize amino acids, minerals and vitamins in the milk and compare with the Mongolian cow's milk. And also was studied fractional structure of goat's milk whey proteins.

• Journal of Dairy Science and Biotechnology
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• 제32권2호
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• pp.111-119
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• 2014

다양한 기능성을 갖는 유청과 표고버섯을 혼합한 기능성 음료를 개발해 유청의 활용 범위를 높이고자, 유청과 표고버섯을 혼합하여 유산균 발효를 시킨 다음, 발효 전 후 성분 비교, 항산화 활성 평가 및 관능검사 등을 실시한 결과는 다음과 같다. 표고버섯 첨가량에 따른 pH 변화는 버섯 첨가량이 증가할수록 약간 감소하는 경향을 보였으나, 시료구별 큰 유의적인 차이를 보이지 않았다. 산도는 표고버섯 첨가량이 증가할수록 높아지는 걸 확인하였다. 표고버섯 첨가 유청 발효액의 유산균수는 $10^{11}$까지 확인되어 유산균 음료로의 가능성을 확인하였다. 발효 전 유청과 발효 후 유청 발효액의 단백질 함량은 유의적인 차이를 보이지 않았고, 지방 함량은 0.31%에서 0.63%로 발효 후 유청 발효액이 약 2배 정도 증가하였다. 유리당은 lactose의 경우, 발효 전 4.83%에서 발효 후 2.48~2.61%로 급격히 감소하였다. 유리아미노산 함량은 발효 전 유청은 196.7 mg%였고, 발효 후 유청 발효액의 경우 260.16~462.16 mg%로 함량이 증가하였다. 발효 전 후 DPPH radical 소거 활성은 유산균 접종 후 즉시 측정한 값과 비교해, 발효 24시간째 측정한 값이 모든 시료구에서 높게 나타났다. ABTS radical 소거 활성은 DPPH radical 소거 활성 측정 결과와 마찬가지로 발효한 시료가 발효 전 시료에 비해 활성이 매우 높게 나타났다. 발효 전 후 산화질소 생성량은 발효 후의 산화질소 생성량이 발효 전의 산화질소 생성량에 비해 낮아지는 경향을 보였다. 유청 발효액의 관능평가 결과는 색, 맛 및 종합기호도 항목에서는 1.0% 첨가구에서 4.7, 4.5 및 4.8로 가장 높은 기호도를 보였다. 유청 발효액의 브랜딩을 통한 유청 음료의 관능평가 결과, 브랜딩 후 유청 음료는 7~8점 정도의 기호도를 보여 음료로써의 기호도 값을 확보하였다. 표고버섯향 첨가량에 따른 기호도를 보면 0.01% 첨가 시료구에서 모든 항목의 기호도가 높게 나타났다.