• 한국축산식품학회지
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• 제32권5호
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• pp.627-634
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• 2012

This study was carried out to investigate the physical and thermal properties of ${\kappa}$-carrageenan (${\kappa}$-car) gel added whey protein isolate (WPI) as a cryoprotectant. The concentration of ${\kappa}$-carrageenan was fixed at 0.2 wt%. The mean ice crystal size of the WPI/${\kappa}$-car was decreased according to increasing whey protein isolate concentration. The temperature of gel-sol (Tg-s) and sol-gel (Ts-g) transition of WPI/${\kappa}$-car maxtrix was represented in the order of 3.0, 0.2, 5.0 and 1.0 wt%. In addition, the transition temperature of gel-sol of WPI in sucrose solution were showed in order of 1.0, 5.0, 0.2 and 3.0 wt% depending on whey protein isolate concentration. The shape of ice crystal was divided largely into two types, round and rectangular form. 1.0 wt% WPI/${\kappa}$-car matrix at pH 7 and 9 showed minute and rectangular formation of ice crystals and whey protein isolate in sucrose solution at a concentration of 1.0 wt% WPI/${\kappa}$-car matrix at pH 3 and 5 showed relatively large size and round ice crystals. The ice recrystallization characteristics and cryprotective effect of ${\kappa}$-carrageenan changed through the addition of different concentrations of whey protein isolate. It seems that the conformational changes induced interactions between whey protein isolate and ${\kappa}$-carrageenan affected ice recrystallization.

• Journal of Nutrition and Health
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• 제28권5호
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• pp.406-414
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• 1995

Nitrogen(N) concentration of preterm(PT) and term (T) milk in various fractions, such as total, protein, nonprotein, whey protein and casein were determined at 2-5 days, 1, 2, 4 and 6 weeks of postpartum. The purpose of this study was to investigate the nitrogen concentration of human milk from mothers delivering at preterm and term, and the propriety of preterm milk for premature infants. The concentration of total N, nonprotein N, protein N, whey protein N and casein N in preterm milk was decreased significantly with time postpartum. Total N was 374mg/이 at colostrum, 232mg/dl at mature milk. Whey protein N was decreased from 42mg/dl at 2-5 days to 32mg/dl at 4-6 weeks. Protein N was 332mg/dl at colostrum, 202mg/dl at mature milk. The proportion of whey protein N and casein N were 39:61 at colostrum, 28:72 at mature milk. No difference were found between T and PT milk for total nitrogen excepted 2 weeks. In this report we show that nitrogen concentration except casetpt casein N is smaller in milk from mothers giving birth prematurely than in milk from mothers giving birth at term, over the first two weeks of lactationl But protein N was higher in preterm milk than term milk, whey protein nitrogen was lower. By comparing predicted nitrogen intakes to estimated requirements of preterm infants fed 150 to 200ml/kg/day of their own mother's milk, we predict that the quantities of protein provided would be adequate to meet the requirements of the prematured infants during the early weeks of life.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.122-125
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• 1997

The utilization of excess whey is necessary to reduce dairy waste because the large amount of whey disposal in waste streams has caused environmental problems. During whey protein film production as the effective means of utilization of excess whey, we have examined the effects of pH, temperature, and plasticizers for water vapor permeability(WVP), tensile strength(TS), and elongation rate(%E) of the whey protein films. The 10% whey protein films had the highest WVP(28.73g$.$mm/kPa$.$day$.$㎡) and TS(1.85${\pm}$0.11Mpa). But, in this case, an increase of WVP was caused by the thickness of whey protein films. At the concentration of 8% whey protein, appropriate thickness was obtained. Whey protein films prepared at the pH 6.75 and 95$^{\circ}C$ showed lower WVP(28.38g$.$mm/kPa$.$day$.$㎡) and elongation rate(12.9%) and higher TS value(3.769${\pm}$0.407 MPa) than at the pH 6.75 and 75$^{\circ}C$. As the temperature increased, WVP of films decreased slightly and tensile strength increased slightly, while elongation rate decreased significantly. Higher WVP and TS were observed at pH6.75 compared to pH7-9. In contrast, significantly higher elongation was observed at pH 9comapred to pH6.75-8. Among the plasticizer types used, the addition of sorbitol showed the highest TS value(6.244${\pm}$0.297 MPa) at the concentration 0.4g sorbitol and elongation rate(49%) at the concentration of 0.6g sorbitol.

• 농업과학연구
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• 제50권2호
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• pp.323-336
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• 2023

As a byproduct obtained from cheese manufacture, whey protein was developed as a functional food that contains multi-functional proteins. In this study, the biochemical activity of fermented milk prepared by fortifying whey protein with excellent physiological activity was investigated. Immunoglobulin (IgG) content was higher in 10% fortified whey protein fermented milk than in the control. The viable cell counts were 20% higher in the fermented milk with 10% fortified whey protein than in the control group. The antibacterial effect of 10% fortified whey protein fermented milk compared to the control group was shown to be effective against four pathogenic microorganisms, Escherichia coli (KCTC1039), Pseudomonas aeruginosa 530, Salmonela Typhimurium (KCTC3216), and Staphylococcus aureus (KCTC1621). The antioxidant effect by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities wasincreased two-fold in 10% fortified whey protein fermented milk compared to the control. The 10% fortified whey protein fermented milk inhibited the expression of the inflammatory cytokines (interleukin [IL]-6, tumor necrosis factor [TNF]-α, and induced nitric oxide synthase [iNOS]) in a concentration-dependent manner. In a piglets feeding test, the weight gain with 10% fortified whey protein fermented milk was increased by 18% compared to the control group, and no diarrhea symptoms appeared. Our results clearly demonstrated that 10% fortified whey protein fermented milk could be a useful functional ingredient for improving health.

• Preventive Nutrition and Food Science
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• 제10권3호
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• pp.231-238
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• 2005

A standard $1\%$ w/v solution of CM-chitosan made from squid pen was added to milk at levels of $0.5\sim3\%$ (v/v) to improve the yield and rheological properties of cottage cheese by whey protein retention. Cheese curd did not form at levels higher than $3\%$ (v/v) CM-chitosan standard solution. Yield and total protein of cottage cheese increased up to $2\%\;by\;11\;to\;42\%\;and\;17\;to\;38\%$ respectively, compared to control cheese. Whey protein losses were decreased by 11 to $42\%$ and thus accounted for all of the increase in yield. Anomalous results were obtained at the $0.8\%$ level, which neither improved yield or whey protein retention nor stabilized rheological parameters, and at the $0.5\%$ level, which improved yield and total protein without increasing whey protein retention. Elasticity and cohesiveness of CM-chitosan-containing cheese were generally improved and stabilized during storage. Monitoring of cheese chromaticity values for four weeks revealed a delay in the onset of yellowing in cheeses with CM-chitosan compared to the controls, while the concentration of added CM-chitosan had little influence on cheese chromaticity. The addition of CM-chitosan solution could be applied directly to industrial scale cottage cheese-making without the need for any modification of the production process.

• Food Science and Biotechnology
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• 제14권1호
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• pp.131-136
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• 2005

The selective extraction behavior of lactoferrin (Lf) from whey protein mixture was examined using reverse micelles formed by the cationic surfactant, cetyldimethylammonium bromide (CDAB). The major whey proteins, including ${\beta}$-lactoglobulin, ${\alpha}$-lactalbumin and bovine serum albumin, were solubilized from aqueous phase to organic phase while Lf was recovered in the aqueous phase. The solubilization behaviors of the proteins were manipulated by the process parameters such as the pH and salt concentration of the aqueous phase and the surfactant concentration in the organic phase. Efficient forward extraction was achieved with sodium borate buffer (50 mM, pH 9) containing 50 mM KCl and organic phase containing 100 mM CDAB. Based on SDS-PAGE and densitometry, about 96% of the initial Lf remained in the aqueous phase after forward extraction. The dialyzed Lf fully maintained its bacteriostatic activity against E. coli O157:H7.

• 한국축산식품학회지
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• 제43권3호
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• pp.512-530
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• 2023

The present study evaluated the effects of fermented whey protein using kimchi lactic acid bacteria Lactobacillus casei DK211 on skeletal muscle mass, muscle strength, and physical performance in healthy middle-aged males performing regular resistance exercises. Effective protein supplementation and regular exercise are two important factors for improving muscle health. Therefore, in this study, the effects of consuming fermented whey protein twice a day were investigated and compared with that of non-fermented supplementation. Forty-eight males (average age 44.8) were randomly assigned to two groups: Fermented whey protein supplementation (FWPS) and non-fermented whey protein concentration supplementation (WPCS) groups. Each group ingested 37 g of FWPS or WPCS twice a day for eight weeks. Body composition, muscle strength, and physical performance were assessed pre- and post-intervention. Independent t-tests or chi-square tests for the categorical variables were performed for analyzing the observations. FWPS was effective in promoting the physical performance in dynamic balance measurement and muscle health, indicated through the increment in grip strength (left), upper arm circumference, and flat leg circumference from the baseline. However, similar improvements were not observed in the WPCS group. These results imply that whey protein fermented by L. casei DK211 is an effective protein supplement for enhancing muscle health in males performing regular resistance exercises.

• Food Science and Biotechnology
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• 제18권3호
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• pp.610-617
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• 2009

The stability of corn oil-in-water emulsions coated by milk proteins, sodium caseinate (CAS), or whey protein concentrate (WPC), was compared under the environmental stress of pH change. Emulsions were prepared at 0.1 of protein:oil because the majority of droplets were relatively small ($d_{32}=0.34$ and $0.35\;{\mu}m$, $d_{43}=0.65$ and $0.37\;{\mu}m$ for CAS- and WPC-emulsions, respectively) and there was no evidence of depletion flocculation. As the pH of the emulsions was gradually dropped from 7 to 3, there was no significant difference in the electrical charges of the emulsion droplets between the 2 types of emulsions. However, laser diffraction measurements, microscopy measurements, and creaming stability test indicated that WPC-emulsions were more stable to droplet aggregation than CAS-emulsions under the same circumstance of pH change. It implies that factors other than electrostatic repulsion should contribute to the different magnitude of response to pH change.

• 한국축산식품학회지
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• 제31권4호
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• pp.543-550
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• 2011

Various concentrations of whey protein isolate (WPI), such as 0.1, 0.5, 1.0, 2.5, and 5.0%(w/v), containing 1.0%(w/v) eugenol were prepared by high speed homogenization to formulate nanoemulsions (NEs) and to investigate their antimicrobial activity. The results showed that particle size decreased according to increases in WPI concentration. Similarly, the ${\zeta}$-potential value was reduced to a negative charge when using WPI concentrations >0.1%(w/v). In contrast, no significant differences in particle size were observed during 1 mon of storage, except for the 0.1%(w/v) WPI NE. The ${\zeta}$-potential value depended on the increase in WPI concentration and storage duration, except for NE1 and NE5, suggesting that a low or high concentration of emulsifier was not effective for maintaining the droplet form of the eugenol NE. The results of an antibacterial effect investigation indicated that the growth of Escherichia coli was inhibited based on an increase in eugenol concentration in all NE formulations. Moreover, a membrane permeability study showed that total leakage content increased according to incubation time.

• 한국식품영양과학회지
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• 제37권4호
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• pp.428-436
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• 2008

본 연구에서는 고지방식으로 유도한 식이성 비만 모델 수컷 흰쥐에게 고지방식이와 함께 유청단백질 및 유청단백질 가수분해물을 급여하였을 때, 유청단백질 가수분해물의 섭취에 따른 체중, 장기 및 체지방, 지질 농도 및 식욕 조절호르몬에 대한 영향을 살펴보았다. 즉, 실험동물 흰쥐에게 18% 우지를 첨가한 고지방식을 기본으로 하여 질소원으로 유청단백질(whey protein concentrate 80: WPC80, 매일유업(주)) 10%를 4주간 공급한 후(control period), 4군으로 나누어서 고지방식을 기본으로 유청단백질, 유청단백질 가수분해물(whey protein hydrolysate), 유청 macropeptide fraction(whey macropeptide fraction; WH중 MW${\geq}$10,000)의 3종을 함유한 실험식이를 각각 6주 동안 급여하였다. 그 결과는 다음과 같다. 체중증가량 및 식이섭취량은 유청단백질 수준이나 가수분해물 섭취에 따른 실험군간 유의적 차이가 없었다. 간의 무게는 가수분해물 섭취에 의해 감소하였으나, 신장, 고환 및 비장의 무게는 실험군간 유의적 차이가 없었다. 한편, 신장의 무게는 고단백 식이에 의해 유의적으로 증가하였다(p<0.05). 지방조직의 무게는 신장 주변 지방과 부고환 주변 지방 모두 유청단백질 수준이나 가수분해물 섭취에 따른 차이를 보이지 않았다. 혈청의 총 지질과 중성지방은 가수분해물 섭취에 의해 유의적으로 낮게 나타났다(p<0.05). 반면, 혈청의 총 콜레스테롤과 HDL 콜레스테롤은 유청단백질 수준과 가수분해물 섭취에 따른 차이를 보이지 않았다. 간 조직의 총 지질, 중성지방과 총 콜레스테롤은 가수분해물 섭취에 따라 차이가 없었으며, 고단백식이에 의해 유의적으로 감소하였다(p<0.05). 일일 분 배설량은 고단백식이에 의해 유의적으로 증가하였다(p<0.05). 분 중 총 지질함량과 중성지방 함량은 가수분해물 섭취 시 그 함량이 유의적으로 증가하였다(p<0.05). 반면, 분 중 총 콜레스테롤 함량은 유청단백질 수준이나 가수분해물 섭취에 따른 영향을 받지 않았다. 혈청 중 glucose와 insulin 농도는 가수분해물 섭취 시 유의적으로 감소하였다(p<0.05). 혈청 중 leptin 농도는 유청단백질 수준이나 가수분해물 섭취에 따른 유의적인 차이를 보이지 않았다. 혈청 중 ghrelin 농도는 고단백 식이에 의해 유의적으로 감소하였으며(p<0.05), 특히, 가수분해물 섭취 시 감소하는 경향을 보였다. 이상의 결과로부터 유청단백질 가수분해물의 섭취는 intact 유청단백질보다 흰쥐의 혈청과 간의 지질 농도를 저하시키고, 분 중으로의 지질배설량을 증가시키는 것으로 나타났다. 또한 혈중 glucose 농도와 insulin 농도를 감소시킴으로서 인슐린 저항성을 개선시켰으며, ghrelin 감소를 통한 식욕조절 효과를 보였다. 한편, 본 연구에서 유청단백질 가수분해물이 체중감소나 조직의 지방량에는 영향을 미치지 않았는데, 이것은 본 연구에서 사용된 25% 단백질 수준이 체중감소나 조직 지방량에 영향을 미치기에는 부족한 수준이라 사료되며, 단백질 수준에서의 증가 또는 보다 장기간 동안의 섭취가 수행되어진다면 식욕 촉진 호르몬 분비 감소를 통해 체중 감소에 있어서 더 유의적인 효과가 나타날 것으로 사료된다.