Galacto-oligosaccharides (GOS) are prebiotics that have a beneficial effect on human health by promoting the growth of probiotic bacteria in the gut, in addition to having various applications in the food industry. GOS are generally produced from lactose in a reaction catalyzed by ß-galactosidase. Synthesis of GOS from whey permeate (WP) (ultrafiltration of whey, concentrated then spray dried) using surface engineered β-galactosidase in Pichia pastoris (P. pastoris) is a novel method to convert waste into a valuable product. Cell-surface display is the expression of peptides and proteins on the surface of living cells by fusing them to functional components of cells. Surface engineered cells have many potential uses. The Flo1p flocculation functional domain, thought to be located near the N terminus, recognizes and adheres non-covalently to cell-wall components such as α-mannan carbohydrates, causing reversible aggregation of cells into flocs.

Whey is a major by-product of cheese manufacture and contains many valuable constituents, such as β-lactoglobulin, lactoferrin and immunoglobulin. The current study determined the anti-biofilm activity of bioconversion of whey by Lactobacillus plantarum (LP-W), L. rhamnosus GG (LR-W), L. brevis (LB-W) and Enterococcus faecium (EF-W) against foodborne pathogenic bacteria, Escherichia coli O157:H7 and Listeria monocytogenes. When the foodborne pathogenic bacteria were co-incubated with LP-W, LR-W, LB-W or EF-W, biofilms by E. coli O157:H7 and L. monocytogenes were significantly reduced by all bioconversion of whey. Moreover, LP-W, LR-W, LB-W and EF-W also dramatically reduced pre-formed biofilm by E. coli O157:H7 and L. monocytogenes, suggesting that the bioconversion of whey effectively suppress the development and disruption of biofilm by foodborne pathogenic bacteria. Furthermore, in order to determine the growth kinetics of E. coli O157 and L. monocytogenes planktonic cells in the presence the bioconversion of whey, LP-W, LR-W, LB-W and EF-W did not significantly inhibited the growth of foodborne pathogenic bacteria, implying that the bioconversion of whey reduces the biofilm without the decrease of bacterial growth. Taken together, these results suggest that bioconversion of whey by lactic acid bacteria could be a promising agent for the reduction of microbial biofilm.

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.

The effects of substituting whey protein concentrate (WPC) powder for rice flour in the preparation of seolgiddeok were determined by objective and subjective tests. Milk whey is drained from milk curd as a by-product of the cheese manufactureing process. Whey protein is known as a good nutritional source and is a functional material for many processed foods. WPC contains more than 80% whey protein. The moisture content decreased gradually during storage and the decrease in moisture was less in the control than in the WPC powder substituted groups. The color lightness (L) decreased significantly as the amount of WPC powder increased, wherease redness (a) and yellowness (b) both increased. Texture analyses revealed that the hardness, chewiness, gumminess and adhesiveness of seolgiddeok tended to increase in proportion to the amount of WPC powder in the formula. Seolgiddeok gelatinization was investigated by amylographing. Initial pasting temperature, peak viscosity, hot pasting viscosity and breakdown were low in seolgiddeok prepared with WPC powder substituted for rice flour. Setback had the lowest value in the control. Sensory evaluations revealed that, seolgiddeok prepared with 3% WPC powder had the highest overall acceptability score. These results indicated that WPC seolgiddeok with 3% WPC powder has the best quality.

본 연구에서는 농축유청단백질을 이용하여 내부젤화 방법으로 나노크기(<~200 nm)의 W1/O/W2 다중 에멀젼을 제조하고, 제조 공정요인(가교제인 CaCl2 농도, 초음파처리, 유화제)에 따른 나노다중에멀젼의 형태학적, 물리화학적(입자크기, 다분산지수, 제타전위) 특성 평가와 모델 유식품(우유, 요구르트, 치즈)을 이용한 저장 안정성을 연구하였다. 나노다중에멀젼의 형태학적 특성은 투과전자현미경을 이용하여 관찰하였으며 물리화학적 특성 및 유식품 저장 안정성 평가는 입도분석기를 이용하여 수행되었다. 실험 결과 가교제인 CaCl2을 첨가함에 따라 다중에멀젼의 크기가 유의적으로(p<0.05) 감소하였으며, 이용된 CaCl2 모든 농도(0, 4, 6, 8 mM)에서 음전하를 지닌 다중에멀젼은 다분산지수 0.2 이하의 균질의 입자 분포를 지니고 있음을 알 수 있었다. 또한 투과전자현미경을 이용하여 관찰한 결과, ~ 180 nm 크기의 내부에 오일상이 포함된 구형의 나노다중에멀젼이 성공적으로 제조되었음을 확인하였다. 초음파 처리시 다중에멀젼 크기는 유의적으로(p<0.05) 감소하였으며, 다분산지수 0.2 이하의 나노다중에멀젼이 생성됨을 확인하였다. 또한 수상 내 유화제 첨가 시 입자크기가 유의적으로(p<0.05) 감소하였고, 다분산지수 0.2 이하의 나노다중에멀젼이 생성됨을 확인하였다. 모델 유식품 저장 환경에서의 안정성 평가 결과 14일 동안 나노다중에멀젼은 물리화학적 안정성을 유지하였으며, 결과적으로 농축유청단백질 나노다중에멀젼은 유식품 적용성이 뛰어남을 확인하였다.

본 논문은 동결건조 유청발효물(Freeze-dried fermentedwhey; FDFW)과 프럭토올리고당(Fructooligosaccharide;FOS)의 비피도박테리아 증식능을 비교 검증한 내용이다.FDFW와 FOS 모두 비피도박테리아 균주 Bifidobacteriumlactis BL 750과 Bifidobacterium longum FI10564에 대해 증식효과가 우수한 것으로 확인되었으며 통계적인 유의 차는없었지만 FDFW가 FOS에 비해 다소 높은 활성을 보였다.흡광도(600nm)를 이용한 실험에서 FDFW 첨가군은 14시간 배양 후 B. lactis 균주는 1.371에 도달하였고 B. longum균주는 1.844에 도달하였다. 반면 대조군으로 사용한 유청첨가군의 경우 각각 1.064와 1.237에 도달하였다. 생균수실험에서는 9시간째 B. lactis 균주에 대한 비피도박테리아증식능이 확인되었고 FDFW 첨가군과 대조군(무첨가군) 사이에 0.38LogCFU/mL의 차이가 관찰되었다. 마지막으로요거트에 첨가된 B. lactis 균주의 보존력을 확인하기 위해10oC에 보관하면서 20일 동안 생균수를 분석한 결과 무첨가군은 6.86에서 4.1LogCFU/mL로 감소한 반면 FDFW(1%)와 FOS(1%) 첨가군은 각각 6.82에서 4.93, 6.81에서4.51로 감소하였다. 이러한 결과들을 종합해 볼 때 FDFW는 비피도박테리아 증식인자로서 사용될 수 있고 또한 기능성 식품소재로서 다양한 낙농제품에 적용될 수 있을 것으로 판단된다.

The effects of substituting whey protein isolate (WPI) powder for rice flour during the preparation of paeksulgi (Korean rice cake) were evaluated by objective and subjective tests. Milk whey is drained from milk curd as a by-product of the cheese manufacturing process. Whey protein is known as a good nutritional source and a functional material for many processed foods. WPI contains more than 90% whey protein. The moisture content decreased gradually during storage and the decrease was less in control than WPI powder-substituted groups. The color lightness (L) decreased significantly with increasing WPI powder, wherease the redness (a) and yellowness (b) both increased. Texture analyses revealed that the hardness, chewiness, gumminess, adhesiveness and fracturability of paeksulgitended to increase in proportion to the amount of WPI powder added. Evaluation of the gelatinization of paeksulgi by amylographing revealed that the initial pasting temperature, peak viscosity, hot pasting viscosity and breakdown was lower in samples that contained WPI powder. However, the lowest setback value was observed in the control. The results of the sensory evaluation indicated that paeksulgi prepared with 2% WPI powder had the highest overall acceptability. Taken together, these results suggest that WPI paeksulgi containing 2% WPI powder has the best quality.

The early diagnosis of bovine pregnancy is an essential component of successful reproductive planning on farms, because lack of bovine pregnancy over the long term results in reproductive failure and low milk yield‐the latter of which is a special concern on dairy farms. This study was designed to identify early pregnancy‐specific whey proteins in bovine, by comparing milk samples collected from cattle during pregnancy (Days 30 and 50) and from non‐pregnant cattle. In this study, differentially expressed proteins in five pregnant and five non‐pregnant Holstein dairy cattle were investigated and compared, using proteomics analysis. The first dimension was applied to a pH 3.0～10.0 strip, by loading a 2‐mg milk protein sample. After the second‐dimension separation was performed, the gels were stained with colloidal Coomassie brilliant blue. The stained gels were scanned and the images were analyzed, to detect variations in protein spots between non‐pregnant and pregnant cattle milk protein spots, using ImageMaster; this was followed by analysis with MALDI TOF‐MS. Analysis of the 2‐DE gel image resulted in a total of approximately 500～600 protein spots, of which 12 spots were differentially expressed, six spots were up‐regulated, and four spots were downregulated; two spots were identified as pregnancy‐specific proteins. These proteins were identified as lactoferrin, NADH dehydrogenase subunit 2, albumin, serum albumin precursor and transferrin. Our results via 2‐D PAGE analysis revealed composite profiles of several milk proteins related to early bovine pregnancy, implying the possible use of these milk proteins in the early detection of bovine pregnancy.

This study examined the quality characteristics of Jeungpyun prepared with different additions of nano-filtered (NF) tofu whey concentrates. The initial pH values of the Jeungpyun batters ranged from 5.64 to 5.78, and decreased to 4.77-4.98 after 4 hours of fermentation at 35oC. The volume and specific volume values of the control Jeungpyun were lower than those of Jeungpyun samples prepared with 1%, 2%, and 3% NF powder. The color of the Jeungpyun became increasingly greenish-yellow as the NF powder level increased. Hardness and brittleness decreased with increasing NF powder content, while cohesiveness and springiness were not significantly different. Sensory evaluations revealed that as the level of NF powder increased, takju smell and sourness increased, but no significant differences were observed for sweetness and moistness between the control and NF powder groups. In terms of overall acceptability, the results revealed that Jeungpyun can be prepared with up to 1% NF powder in place of rice powder and be deemed as acceptable as a control Jeungpyun product.

In this study, physicochemical properties and the antioxidative activity of whey protein isolate(WPI) for com germ oil were measured. The pH of WPI was 6.26, and the titrable acidity was 0.18%. The WPI’s moisture content was 5.2% and each of the other element content such as lactose, crude protein, crude ash and crude fat was found to be 0.8%, 90.7%, 2.7% and 0.6%, respectively. The amounts of active SH group in WPI 9 μ M-g and total colony counts of bacteria was 5.9 × 103 CFU-g. α-Lactalbumin, β-lactoglobulin and bovine serum albumin(BSA) were shown in WPI as major protein by electrophoresis. The antioxidative effect of WPI and other antioxidants on com germ oil used as substrate was determined by peroxide value(POV) and conjuqated dienoic acid value(CDV). By these results, the order of antioxidative effects could be defined as BHT 0.02%〉ascorbic acid 0.1%〉WPI 0.1%〉WPI 0.02%〉ascorbic acid 0.02%〉control〉tocopherol 0.02%〉tocopherol 0.1%, respectively. Also the induction period of com germ oil added with WPI was longer by 1.6 times than that of control(none added any antioxidant). Therefore the fact suggested that WPI could be utilized as a good antioxidative agents.

이 연구는 글루코만난과 유청칼슘의 혼합물이 1%-Cholesterol을 식이한 후 혈청콜레스테롤에 미치는 영향과 70%-Sucrose를 식이한 후 혈당에 미치는 영향을 알아보았다. 1%-Cholesterol을 식이한 쥐를 일반식이군(ND)과 비교하였으며, 고콜레스테롤식이군(HCD)에 글루코만난식이군(HCDG)과 글루코만난과 유청칼슘군식이군(HCDGW)으로 나누어 관찰하였다. 또한 70%-Sucrose를 식이한 쥐를 일반식이군(ND)과 비교하였으며, 고혈당식이군(HGD)에 글루코만난식이군(HGDG)과 글루코만난과 유청칼슘군식이군(HGDGW)으로 나누어 관찰하였다. 이를 비교 조사한 결과를 요약하면 다음과 같다. 1. 혈청콜레스테롤수치는 HCD> HCDG> HCDGW> ND의 순서로 감소하였다. 2. HCD의 혈청콜레스테롤증가량에 비하여 HCDG는 약 23.84% HCDGW는 약 42.38% 감소하였다. 3. 혈당수치는 HGD >HGDG> HGDGW> ND의 순서로 감소하였다. 4. HGD의 혈당증가량에 비하여 HGDG는 약 6.63% HGDGW는 약 63.14% 감소하였다.