초록 ▼

○ 연구결과
우유 내 IGFs는 환경 요인에 따라 함량이 다양해질 수 있으며 초유에 그 함량이 높은 것을 확인하였다. 다양한 유가공 공정 중 IGF-Ⅰ은 대부분 그 활력을 유지하나 멸균 조건과 발효 공정 후 그 함량이 떨어지는 것으로 분석되어 강화 유제품의 개발에 있어서 온화한 살균 조건이 IGF-Ⅰ함량을 유지하는 조건인 것으로 사료하였고 캡슐화를 통한 강화 조건은 다양한 유제품의 저장 안정성을 부여하고 발효 공정 후에도 그 활력을 유지할 수 있는 좋은 기술인 것으로 평가되었다. IGFs 함량을 분석하는 방사선면역측정법의 개선

○ 연구결과
우유 내 IGFs는 환경 요인에 따라 함량이 다양해질 수 있으며 초유에 그 함량이 높은 것을 확인하였다. 다양한 유가공 공정 중 IGF-Ⅰ은 대부분 그 활력을 유지하나 멸균 조건과 발효 공정 후 그 함량이 떨어지는 것으로 분석되어 강화 유제품의 개발에 있어서 온화한 살균 조건이 IGF-Ⅰ함량을 유지하는 조건인 것으로 사료하였고 캡슐화를 통한 강화 조건은 다양한 유제품의 저장 안정성을 부여하고 발효 공정 후에도 그 활력을 유지할 수 있는 좋은 기술인 것으로 평가되었다. IGFs 함량을 분석하는 방사선면역측정법의 개선으로 활성 물질에 대한 분석 방법에 새로운 방향이 모색되었으며 강화된 유제품의 안정성 평가를 통하여 우유로부터 정제된 IGF-Ⅰ이 기능성 식품으로서의 소재가 될 수 있는 것으로 사료되었다.

Abstract ▼

Insulin-like growth Factor-I, namely IGF-I, namely IGF-I is one of the main growth factors in milk and found in milk produced from all mammalian species. It has 70 amino acids residues cross-linked by 3-disufied bonds. The structure of bovine IGF-I is identical with that of human's IGF-I. It stimul

Insulin-like growth Factor-I, namely IGF-I, namely IGF-I is one of the main growth factors in milk and found in milk produced from all mammalian species. It has 70 amino acids residues cross-linked by 3-disufied bonds. The structure of bovine IGF-I is identical with that of human's IGF-I. It stimulates growth, differentiation, and metabolism of various cells.
Thus we examined the change of IGF-I content in bovine milk dring year lactation period and to identify parameters affecting IGF-I content in bovine milk.
The IGF-I content was determined by radioimmunoassay using ¹²⁵I after acid-ethanol treatment. The data were analyzed using GLM and CORR procedures of SAS to examine significant differences (P<0.05) within groups(dairy farms, lactation periods, seasons and parity).
Different feeding pattern between dairy farms may have influenced the content in milk. There were about six fold decrease in the concentration of IGF-I(From 2,462.7 to 353.0 ng/㎖) in colostrum from 6hr after parturition to that of 18hr after parturition. The acid-neutralized colostrum whey samples were fractionated two peaks (p1 and p2) through Sephadex G-50 gel chromatography(pH 6.64), and IGF-I content of peak fractions were determined. Both of the two pooled fractions of ng/㎖ content were similar at 6, 12, 18 hr after parturition. When lactation period classified into three groups such as early, middle and late lactation period, IGF-I content did not show significant difference throughout whole lactation periods. Parity did not result in significant difference IGF-I content.
To show the pattern of radioactivity of IGF binding protein complex sephacryl S-100 neutral (pH 7.0) column chromatography after incubation of ¹²⁵I with milk serum was shown two or three major peaks. The 150-to 200-kDa peak was assumed the complex of ¹²⁵I, Acid Labile Subunit (ALS) and binding proteins and the latter was assumed 50 kDa peak.
And the change of ¹²⁵I content before and after each dairy process was examined . ¹²⁵I content in raw milk and whey was not significantly changed by normal pasteurization conditions. However, IGF-I content in raw milk and whey was greatly decreased after exposure with autoclave condition.
Significant reduction i IGF-I content was found during fermentation with commercial starter culture. IGF-I content decreased from 53.0 to 3.8 ng/㎖ after incubation for 13 hrs (Final pH of 4.06). In term of commercial dairy products, ng/㎖ content of market milk was in the range of 32.9~56.4 ng/㎖. Commercial whole milk powder, skim milk powder, infant formula and sweet cheese whey was 41.3, 55.8, 32.2 and 20.5 ng/㎖, respectively. However,IGF-I content of yoghurt was relatively lower than that of other dairy products and ranged from 7.7 to 17.4 ng/㎖. The changes of IGF-I content in the fortified dairy products during storage were determined. The IGF-I content in the fortified milk and dried milk powder did not show significant difference during the tested storage periods (12 days for milk, 4 weeks for dried milk powder), but the IGF-I content in yogurt was significant decreased (P<0.05) during the storage for 12 days.
As a way to improve storage stability, IGF-I was encapsulated by surface reforming process (hybridization) using enteric coating materials (Sureteric and Eudragit L100-55) and the changes of IGF-I content were monitored. When crude IGF-I was coated with enteric wall materials before fortification, the IGF-I content in yogurt was maintained during fermentation and storage, and no significant differences was found. Surface reforming process resulted in significantly higher remained IGF-I content after fermentation compared to that of uncoated control. Therefore, the enteric coating of IGF-I prior to fermentation can be used as an effective way to prevent degradation of IGF-I during fermentation.
For production of IGF-I moclonal antibody (mAB), Balb/c mouse was immunized with commercial recombinant human IGF-I(rhIGF-I). Immunized cells were harvested from spleen, and fuzed with carinoma cells. Selected 4 hybridoma cell lines by HAT selection medium and indirect immunofluorescence were immunized into Balb/c to obtain the highly immunized ascitic fluid. Specific binding of IGF-I mAb to rhIGF-I (7.5kDa) was shown in Western gybridization and indirect immunofluorescence. Therefore the being of IGF-I mAb in ascitic fluids were confirmed. Binding conditions for radioimmnunoassay (RIA) and enzyme linked immunosorbant assay(ELISA) were modified or etablished by use of IGF-I mAb.
IGF-I peptide in milk were isolated by immunoaffinity chromatography using IGF-I mAb, and their bio-activity was idenfitied , in-vitro and in-vivo. IGF-I peptide which was isolated in milk (mIGF-I) treated each cell lines show increased proligeration, especially in myoblast C2C12. For in -vivo test, ICR mice were infused with the IGF-I concentrated milk, and their body weight were increased. Oral treatment of IGF-I concentrated milk , and their body weight were increased. Oral treatment of IGF-I concentrated milk also induces the incerement of tissue weight, IGFs concentration, and expression of IGF-I and IGF-IR in pheripheral tissue. Therefore mIGF-I was seems to have a significant and specific bio-acitivities.
We also investigated safety evaluation of commercial recombinant Insulin like Growth Factors-I(IGF-I), IGF-I isolated from bovine colostrum which may be applicable to functional foods as raw materials, and enriched milk with IGF-I. In order to evaluate toxicity of IGF-I, genetic toxicity test, acute toxicity test, and short term toxicity test were executed with recombinant IGF-I obtained from R&D systems company, IGF-I isolated from bovine colostrum and enriched milk with IGF-I isolated from bovine colostrum. As a result, any mutagenic effect ofenriched milk with IGF-I isolated from bovine colostrum was not observed in 5 species of Salmonella typhimurium. IGF-I treated groups show n o significant toxicological findings with changes of body weight, food consumption and water consumption and no pathological findings compared with control groups in genetic toxicity test, acute toxicity test, and short term toxicity test.

목차 Contents

• 제출문 ... 1
• 요약문 ... 2
• SUMMARY ... 8
• CONTENTS ... 11
• 목차 ... 12
• 제 1 장 연구개발과제의 개요 ... 13
• 제 1 절 연구 개발의 필요성 ... 14
• 제 2 장 국내외 기술개발 현황 ... 17
• 제 1 절 국내외 기술현황과 문제점 ... 17
• 제 2 절 앞으로의 전망 ... 19
• 제 3 절 기술도입의 타당성 ... 20
• 제 3 장 연구개발수행 내용 및 결과 ... 21
• 제 1 절 제1세부과제 : 유제품 내 IGFs의 강화 방안 연구 ... 21
• 제 2 절 제2세부과제 : IGFs의 생체 내.외에서의 생리화학적 활성 연구 ... 61
• 제 3 절 위탁연구과제 : IGFs 강화 유제품의 안전성 평가 ... 113
• 제 4 절 종합토의 ... 137
• 제 4 장 목표달성도 및 관련분야에의 기여도 ... 139
• 제 1 절 제1세부과제 : 유제품 내 IGFs의 강화 방안 연구 ... 139
• 제 2 절 제2세부과제 : IGFs의 생체 내.외에서의 생리화학적 활성 연구 ... 140
• 제 3 절 위탁연구과제 : IGFs 강화 유제품의 안전성 평가 ... 143
• 제 5 장 연구개발결과의 활용 계획 ... 145
• 제 6 장 연구개발과정에서 수집한 해외과학 기술정보 ... 146
• 제 7 장 참고문헌 ... 147
• 끝페이지 ... 161