• 농업과학연구
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• 제45권4호
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• pp.635-643
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• 2018

Bovine milk is widely consumed by humans and is a primary ingredient of dairy foods. Proteomic approaches have the potential to elucidate complex milk proteins and have been used to study milk of various species. Here, we performed a proteomic analysis using 2-dimensional electrophoresis (2-DE) and matrix assisted laser desorption ionization-time of flight mass spectrometer (MALDI-TOF MS) to identify whey proteins in bovine milk obtained soon after parturition (bovine early milk). The major casein proteins were removed, and the whey proteins were analyzed with 2-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The whey proteins (2 mg) were separated by pI and molecular weight across pH ranges of 3.0 - 10.0 and 4.0 - 7.0. The 2-DE gels held about 300 to 700 detectable protein spots. We randomly picked 12 and nine spots that were consistently expressed in the pH 3.0 - 10.0 and pH 4.0 - 7.0 ranges, respectively. Following MALDI-TOF MS analysis, the 21 randomly selected proteins included proteins known to be present in bovine milk, such as albumin, lactoferrin, serum albumin precursor, T cell receptor, polymeric immunoglobulin receptor, pancreatic trypsin inhibitor, aldehyde oxidase and microglobulin. These proteins have major functions in immune responses, metabolism and protein binding. In summary, we herein identified both known and novel whey proteins present in bovine early milk, and our sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis revealed their expression pattern.

• 한국식품영양학회지
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• 제30권6호
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• pp.1359-1363
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• 2017

The purpose of this study was that the optimal hydrolysis conditions of endo- and exo-type enzymes were selected to utilize organic cheese byproducts. Optimal substrate concentration and optimum enzyme ratio were measured by using 4 kinds of endo-type enzymes (alcalase, neutrase, protamex, and foodpro alkaline protease) and two exo-type enzymes (flavourzyme and prozyme 2000P) for whey protein hydrolysis were analyzed using liquid chromatography. As a result, the optimal endo-type enzyme through the first enzyme reaction was selected as alcalse, and as a result of the secondary enzyme reaction, flavourzme was selected as the Exo type enzyme. The concentration of whey protein substrate for optimal primary and secondary enzyme reactions was 10%. In addition, the optimum ratio of enzyme was 0.5% of alcalase and 0.2% of flavourzyme, which showed low molecular weight chromatography pattern compared to 2% of alcalase and 1% of flavourzyme hydrolyzate. Therefore, hydrolyzing the endo-type enzyme alcalase at a concentration of 0.5% for 10 hours and then hydrolyzing the exo-type enzyme flavouryme at a concentration of 0.2% for 4 hours was considered to be the optimum condition.

• 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.

• 한국축산식품학회지
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• 제37권1호
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• pp.62-70
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• 2017

The aim of this study was identifying a suitable food grade enzymes to hydrolyze whey protein concentrates (WPCs), to give the highest bioactivity. WPCs from ultrafiltration retentate were adjusted to 35% protein (WPC-35) and hydrolyzed by enzymes, alcalase, ${\alpha}-chymotrypsin$, pepsin, protease M, protease S, and trypsin at different hydrolysis times (0, 0.5, 1, 2, 3, 4, and 5 h). These 36 types of hydrolysates were analyzed for their prominent peptides ${\beta}-lactoglobulin$ (${\beta}-Lg$) and ${\alpha}-lactalbumin$ (${\alpha}-La$), to identify the proteolytic activity of each enzyme. Protease S showed the highest proteolytic activity and angiotensin converting enzyme inhibitory activity of IC50, 0.099 mg/mL (91.55%) while trypsin showed the weakest effect. Antihypertensive and antioxidative peptides associated with ${\beta}-Lg$ hydrolysates were identified in WPC-35 hydrolysates (WPH-35) that hydrolyzed by the enzymes, trypsin and protease S. WPH-35 treated with protease S in 0.5 h, responded positively to usage as a bioactive component in different applications of pharmaceutical or related industries.

• 한국식품영양과학회지
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• 제20권6호
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• pp.546-550
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• 1991

우유의 열처리 정도를 검색할 수 있는 지표 설정을 위한 유효성분을 채택하기 위하여 시판우유의 pH, 적정산도, 불변성 유청단백질 함량과 유효성 lysine의 함량 변화를 비교한 결과, pH 및 정적산도는 열처리에 따른 변화가 없었고, serun 100ml당 불변성 유청 단백질 함량은 저온살균유가 413.7mg, 고온순간살균유가 341.3mg, 초고온살균유는 6.9mg, 초고온멸균유는 96.6mg으로 열처리에 따라 뚜렷한 차이가 있었다. 원유에 대한 각 열처리 우유들의 유효성 lysine 감소율은 저온살균유에서 1.4%, 고온순간살균유에서 0.2%, 초고온살균유에서 6.3%, 초고온멸균유에서 4.9%로 초고온처리에서 명확히 구분되지 않았다.

• 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.

• Journal of Animal Science and Technology
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• 제61권2호
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• pp.98-108
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• 2019

Four Korean native steers ($511{\pm}17.2kg$; $2{\times}2$ replicated crossover design) fitted with duodenal cannulas were used to investigate the influence of oral administration of soluble whey protein (WP; 82.29% crude protein) on ruminal fermentation, gastrointestinal (GI) hormone secretion in the blood, pancreatic ${\alpha}$-amylase activity in the duodenum, and disappearance rate in each segment of the GI tract. Steers were orally fed the basal diet (control; TMR [total mixed ration] 9 kg/d) or the basal diet with enriched WP (400 g/d) for 14 days. The apparent crude protein disappearance rate in the rumen of the WP was higher than in control (p < 0.05). However, no difference between groups was observed in the apparent crude protein disappearance rate in the intestine and the apparent starch disappearance rates in the rumen, GI tract. The level of cholecystokinin, secretin, and ghrelin in serum and pancreatic ${\alpha}$-amylase activity in the duodenum of the WP also did not change. The changes in the level of blood urea nitrogen related to protein metabolism were higher in the WP than in the control (p < 0.05). However, the levels of total protein, lipid, carbohydrate and mineral metabolites did not change. Consequently, we suggest that the oral administration of WP in steers assisted in ruminal fermentation due to the population increase of microbes in the rumen but did not improve the starch digestion rate in the small intestine because GI hormone secretion in the blood and pancreatic ${\alpha}$-amylase activity did not change.

• 한국식품과학회지
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• 제51권6호
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• pp.537-542
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• 2019

국내에서 식용으로 유통 및 판매가 가능한 7종의 곤충 중 누에(Bombyx mori), 갈색거저리(Tenebrio molitor) 유충, 흰점박이꽃무지(Protaetia brevitarsis) 유충, 쌍별귀뚜라미(Gryllus bimaculatus)의 4종을 대상으로 단백질을 분리하고, 유청 단백질과 비교하여 항산화 및 영양 특성을 분석하였다. 원물시료에서 분리한 단백질의 수율은 65.0-75.0%로 나타났다. 각 단백질의 아미노산을 분석한 결과, 모든 곤충 시료에서 필수 아미노산인 Phe, Trp은 유청 단백질보다 높은 함량을 보였다. 근육생성에 도움이 되는 세 종류의 BCAA아미노산 중 Val은 모든 곤충단백질에서 유청단백과 유사한 함량을 보였으며, BCAA함량은 곤충분리단백질 중 쌍별 귀뚜라미와 갈색거저리 유충에서 그 함량이 각각 16.8과 16.4%로 가장 높아 유청단백(22.2-23%)의 73-76% 수준인 것으로 나타났다. 곤충 단백질의 총 폴리페놀함량은 유청단백보다 유의적으로 많았으며 곤충단백중에는 누에의 함량이 유의적으로 낮게 측정되었다. 항산화활성 또한 곤충단백이 유청단백보다 유의적으로 높았으며, 특히 갈색거저리 유충에서의 활성이 가장 높게 측정되었다. 관능검사결과에서는 시판 단백질파우더와 동일한 조성으로 제조했을 경우, 유청단백의 25%의 대체가 가능할 것으로 보이나 맛과 향이 대조군에 비해 많이 떨어지므로 보완할 필요가 있다. 곤충단백질은 유청단백질에 비해 BCAA함량은 다소 낮았지만 폴리페놀 함량이 높고 항산화활성이 있으므로 아미노산 조성을 참고하여 특정목적 단백질 제품으로 사용될 가능성이 높음이 확인되었다.

• 동아시아식생활학회지
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• 제26권1호
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• pp.25-33
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• 2016

The study was performed to investigate the effects of whey protein-rich meal substitute added with vitamins, minerals, and lactobacillus powder probiotics on weight loss, body fat, and body composition in 24 female volunteers for 4 weeks. Whey protein-rich meal substitute was consumed with low-fat, high calcium milk (1% fat, 260 mg/200 mL) twice a day. Subjects submitted 3-day diet records and a life-style questionnaire before the study. During the study, subjects were required to turn in a diet record every day and consume the meal substitute formula in the metabolic ward at C university for 4 weeks. Anthropometric measurements were carried out weekly by Inbody 7.0. The dietary intake and anthropometric data were analyzed to compare changes before and after the study by paired t-test with SPSS version 23.0. The subjects were mostly early 20's and either overweight or obese and highly motivated to lose weight. Most of the subjects consumed three meals per day regularly and spent mostly 10~15 minutes for a meal. Their caloric intake was relatively low and decreased from 1,360 kcal at week 0 to 1,100 kcal after 4 weeks. However, total protein intake increased while carbohydrate and fat intakes decreased (p<0.05) after the trial. Nine vitamin intakes after the study improved compared to those before the study (p<0.05). After the study, subjects showed lower body weight (-1.8 kg), body fat (-0.94 kg), percent body fat (-0.86%), as well as waist circumference (-4.52 cm), hip circumference (-0.44 cm), waist hip ratio (-0.05), and triceps skinfold thickness (-2.39 mm) compared to those at week 0 (p<0.05). Muscle mass tended to be less compared to week 0, although there was no significant differences between weeks 0 and 4. In conclusion, diet trial with whey protein-rich meal substitute induced weight loss and positively changed body fat parameters and body composition.

• Asian-Australasian Journal of Animal Sciences
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• 제17권10호
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• pp.1459-1464
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• 2004

The purpose of this research was to investigate the potential use of cheese whey protein (CWP), a cheese by-product. The physiological activity of calcium-binding peptides in CWP may be used as a food additive that prevents bone disorders. This research also examined the characteristics of calcium-binding peptides. After the CWP was heat treated, it was hydrolyzed by trypsin. Then calcium-binding peptides were separated and purified by ion-exchange chromatography and reverse phase HPLC, respectively. To examine the characteristics of the purified calcium-binding peptides, amino acid composition and amino acid sequence were analyzed. Calcium-binding peptides with a small molecular weight of about 1.4 to 3.4 kDa were identified in the fraction that was flowed out from 0.25 M NaCl step gradient by ion-exchange chromatography of tryptic hydrolysates. The results of the amino acid analysis revealed that glutamic acid in a calcium-binding site took up most part of the amino acids including a quantity of proline, leucine and lysine. The amino acid sequence of calcium-binding peptides showed Phe-Leu-Asp-Asp-Asp-Leu-Thr-Asp and Ile-Leu-Asp-Lys from $\alpha$-LA and Ile-Pro-Ala-Val-Phe-Lys and Val-Tyr-Val-Glu-Glu-Leu-Lys from ${\beta}$-LG.