인삼(Panax ginseng) 사포닌이 두유의 저장 안정성에 미치는 영향

학위논문 (석사)-- 서울대학교 대학원 : 국제농업기술대학원 국제농업기술학과, 2019. 2. 정동화.대두 (Glycine max)는 35-40%의 높은 식물성 단백질을 함유하고 있으며, 또한 saponin, isoflavone 및 oligosaccharide와 같은 건강기능성 물질을 가진 작물로써, 세계인의 식생활에서 중요한 작물 중 하나이다. 그러나 대두는 trypsin inhibitor, phytate 및 lectin과 같은 영양 저해 인자를 함유하므로 대두는 섭취 전에 열처리 또는 가공공정이 필요하다. 대두가공식품은 발효 유무에 따라서 발효식품(간장, 된장, 청국장 등)과 비발효식품 (두유, 두부, 콩가루 등) 2가지로 분류된다. 특히 비발효식품 중 하나인 두유는 대두를 물에 불린 뒤, 갈아 만든 음료로써, 예로부터 고품질 식물성단백질의 공급원이면서, 유당불내증 환자를 위한 우유 대체 식품으로 전세계적으로 많이 소비되고 있는 건강기능성 음료이다. 그러나 두유는 저장 중 (1) 회분, 불용성 단백질, 섬유질과 같은 불용성 물질 (2) 두유 단백질 간 입자 응집에 의한 침전이 발생하며, 이는 두유의 물리화학적 성질(입도크기, 미세구조 및 탁도), 조직감 및 감각과 같은 두유의 품질을 손상시킨다. 두유의 입자 침전은 Stokes law: V=2∆ρgα^2/9η에 따라 두유 입자의 크기, 두유의 밀도, 점도에 영향을 미치며, 다음의 요인을 조절하여, 두유의 저장 안정성을 향상시킬 수 있다. 두유의 저장 안정성을 향상시키는 방법은 (1) 초고압균질 공정, (2) Hydrocolloid 첨가 등이 있다. (1) 초고압균질 공정의 경우, 두유를 초고압을 가하여 노즐을 통과시키고, 이때 발생하는 cavitation, 전단력 등을 두유 입자에 작용하여, 입자를 미세화, 분산시키는 방법이다. 그러나 초고압균질의 경우 (a) 초고압에 의해 발생한 마찰열에 의한 두유 미량성분의 파괴, (b) 고가의 설비 및 생산비용의 문제점이 있다. (2) Hydrocolloid 첨가의 경우, 두유에 hydrocolloid (자당 지방산에스테르, 모노글리세라이드, 카라기난 등)를 첨가, 분산시켜 두유의 점도 또는 겔 형성 특성을 변화시키는 방법이다. 그러나 특정 hydrocolloid는 pH 및 염과 같은 환경적 요인에 영향을 많이 받으며, 또한 hydrocolloid 섭취 시 위장관에서 병변이나 암을 유발할 수 있다고 보고되었고, 또한 여전히 식품안정성에 대해 입증되지 않았다. 최근 계면활성제가 콜로이드 입자와 상호작용하여, 식품 계면 특성을 변형, 입자 응집 억제, 및 복합체를 형성할 수 있으며, 또한 음료의 저장 안정성을 향상시킬 수 있다고 보고되었다. 계면활성제 중 인삼(Panax ginseng) 사포닌은 천연 계면활성제로써, 항암, 노화방지, 면역 체계 향상, 혈관 운동 개선 등의 건강기능성과 더불어 식품안전성이 입증된 물질이다. 또한 사포닌은 단백질과 상호작용하여, 복합체를 형성하며, 또한 단백질의 친수성을 향상시켜, 저장 중 단백질 응집을 억제하는 기능이 보고되었다. 본 연구는 천연 계면활성제인 인삼 사포닌이 두유의 저장 안정성에 미치는 영향에 대해 조사하였다. 두유 연구는 인삼 사포닌에 의해 유도되는 두유 안정화 메커니즘을 알아보고자 두유 계면 모델 시스템(Chapter 2)에서 계면 특성 실험을 진행하였고, 또한 인삼 사포닌이 두유의 저장 안정성 향상 유무를 확인하고자 실제 두유 시스템(Chapter 3)에서 저장 안정성 실험을 진행하였다. 두유 계면 모델의 계면 특성 분석은 분리대두단백(SPI, 순도≥90%)과 인삼 사포닌 분말(GSP, 순도≥80%)을 각각 인산완충용액(pH 7)에 첨가하고, 혼합, 수화 시킨 용액을 이용하였다. 혼합된 SPI-GSP 계면 시스템은 (1) 불포화 계면층: 〖10〗^(-5)%, w/w SPI 고정, (2) 포화 GSP 계면층: 〖10〗^(-2)%, w/w GSP 고정, (3) 포화 SPI 계면층: 〖10〗^(-2)%, w/w GSP 고정, 총 3가지 농도에서 wilhelmy plate 방법을 사용하여 동적 계면장력을 측정하였다. 평형 계면장력은 동적 계면장력 결과를 외삽하여 결정하였다. 혼합된 SPI-GSP 용액은 GSP-SPI 복합체를 형성할 수 있으며, GSP와 SPI가 낮은 농도 범위 내(〖≤10〗^(-3)%, w/w GSP and SPI)에서 상승 효과를 나타낸다. 반면에 높은 농도 범위 내(〖≥10〗^(-3)%, w/w GSP and SPI)에서 혼합용액의 계면 특성은 GSP/SPI 비율에 따라 변화한다. GSP / SPI의 각각 낮은 비율과 높은 비율에서 계면 장력은 각 SPI와 GSP의 계면장력과 유의적으로 일치한 값을 나타낸다. 이는 GSP와 SPI가 경쟁 흡착 관계이며, GSP / SPI의 계면에서의 비율에 따라 흡착 거동을 조절할 수 있음을 의미한다. 또한 이는 현탁액 또는 유화액 식품 시스템의 형성 및 안정성 조절에 유용하게 이용할 수 있을 것이다. 실제 두유 시스템에서 인삼 사포닌이 두유의 저장 안정성에 미치는 영향을 조사하였다. 두유 샘플은 일반적인 두유 제조공정을 이용하였고, 두유에 인삼 사포닌 분말(GSP)을 0, 0.5, 1, 1.5, 2, 3%, w/w로 첨가한 샘플을 실험에 사용하였다. 두유의 저장 안정성 분석은 저장온도 4, 25, 37 °C에서 35일 저장기간 동안 각 (1) 저장수명: 미생물 생장 및 pH, (2) 저장 안정성 확인: 두유 외관, 입도크기, 제타포텐셜, (3) 유변학적 특성 총 3분류로 나뉘어 분석하였다. 두유의 저장 수명은 저장 온도 및 GSP 농도에 관계없이 저장 기간 중 미생물이 확인되지 않았으며, 또한 pH는 6.2-6.4 값의 일정한 값을 유지하였다. 두유의 저장 안정성은 저장 온도가 낮을수록 두유의 침전이 천천히 발생하였고, 저장 안정성이 향상되었다. 이는 제타포텐셜 결과에 따라 두유를 4 °C에서 저장한 경우, 더 큰 정전기적 반발력이 발생하여 두유의 입자 응집이 억제되기 때문으로 예상되며, 또한 두유의 유체특성 결과에 따라 저장 온도 4 °C에서 두유는 더 큰 점성특성을 나타내었고, 따라서 Stokes law에 의해 두유의 입자 침전속도가 천천히 발생하기 때문으로 예상된다. 마찬가지로 GSP 농도가 증가함에 따라 두유는 더 큰 점성 특성을 나타내었다. 이는 두유의 총 고형물의 증가 또는 Inter-molecular links (ginsenoside 미셸과 두유 단백질 내 펩타이드와 결합)를 형성하기 때문으로 예상된다. 그러나 GSP의 첨가는 두유 입자 응집 및 침전을 포함하여 두유의 저장 안정성에 거의 영향을 미치지 않았다. 이는 두유가 고 단백질 함량 및 많은 종류의 성분을 함유하는 복잡한 시스템이기 때문으로 예상된다. Ginsenoside가 두유의 저장 안정성에 미치는 구체적인 효과를 확인하기 위해 두유 현탁액 또는 유제 모델과 같은 단순한 시스템을 만드는 등 추가 실험이 필요하다. 이 연구는 저장 온도 및 저장 중 천연 계면 활성제 (ginsenosides) 첨가와 같은 다양한 조건에서 두유 입자 침전 과정을 구체적으로 기술하였으며, 또한 두유 계면 모델 시스템에서 ginsenoside가 두유 콜로이드 입자와의 상호작용 메커니즘을 확인하였다. 이는 두유 가공 및 소비의 활용도를 높이고 식품 산업 활용도를 높일 수 있으며, 또한 식품 인터페이스 및 분산 (거품, 유제) 시스템의 안정화 및 저장 안정성을 설명하는데 도움이 될 수 있습니다.The soybean (Glycine max), which contains 35-40% plant proteins, and health functional substances such as saponin, isoflavone, and oligosaccharide, is major source of plant protein and in the human food. However, it also contains trypsin inhibitor, phytate and lectins as anti-nutritional components. Consequently, soybean must be subjected to proper treatment such as thermal, acidic, and ultra-sonication etc. before consumption by human beings to reduce these anti-nutritional contents Soy processed foods may be divided into two classes: fermented foods (soy sauce, soybean paste etc.) and non-fermented foods (soymilk, tofu, soybean flour etc.) Especially, soymilk is the extract obtained after soaking, grinding, cooking and filtering the soybean. It has gained much popularity as a healthy plant-based beverage and easily digestive products. However, soymilk often shows some precipitation during long-term storage and this is susceptible to quality loss, which may adversely affect physicochemical properties (particle size, microstructure, and turbidity), textural, sensory properties of soymilk and limit soymilk utilization. According to Stoke's law: V=2∆ρgα^2/9η, the particle precipitation of soymilk influences the particle size, density and viscosity of soymilk. Also, it can improve the storage stability of soymilk by controlling these three factors. To improve storage stability of soymilk, previous studies were mostly focus on using the ultra-high pressure homogenization equipment, and the addition of hydrocolloids. Ultra-high pressure homogenization in soymilk can enhance shelf-life, colloidal stability, and reduce the average particle size and settling. However, it can cause protein denaturation and degradation of several compounds Adding hydrocolloids in soymilk showed that it interacted with soymilk particles. It can inhibit the particle aggregation and decreased particle precipitation. However, some kinds of hydrocolloids reported that may cause lesions or cancer in the gastrointestinal tract. And the hydrocolloid is sensitive to environmental factors, such as pH, thermal treatment, and ion species. Many researches show that surfactant also can improve stability of emulsion to interact with particles and form the complexes in beverages. Also, this complex can inhibit the protein aggregation and precipitation, thereby the storage stability of the beverage improved. Recently, researchers have reported that ginseng (Panax ginseng) saponin as one of the natural surfactant, also can interact with protein, and make the complex that can improve emulsion stability and change interfacial properties. In addition, it was well known for their health benefits, anti-cancer, and anti-aging. The aim of this study is to characterize an influence of ginsenosides as a natural surfactant on storage stability of soymilk during stored under various conditions (4, 25, 37 °C). The study was divided into two categories: soymilk interface model system (chapter 2) to understand the soymilk stabilization mechanism induced by ginsenosides, and soymilk products (chapter 3) to investigate the effect of GSP on storage stability of soymilk. Interfacial characteristics of mixed soy protein isolate (SPI, purity≥90%) and ginseng saponin powder (GSP, purity≥80%) was studied at air/water interface (Chapter 2). To investigate the change of interfacial properties of mixed GSP-SPI depending on the mass ratio of GSP/SPI, Mixed protein-surfactant system was divided into three concentration profiles: (1) unsaturated interface layer: fixed 〖10〗^(-5)%, w/w SPI, (2) saturated GSP interface layer: fixed 〖10〗^(-2)%, w/w GSP, and (3) saturated SPI layer: fixed 〖10〗^(-1)%, w/w SPI. Dynamic interfacial tension on the timescale 0-5 h was measured using a wilhelmy plate method. The dynamic interfacial tension and extrapolated equilibrium interfacial tension are discussed from the point of view of a mixed GSP-SPI, with interfacial properties of the mixed GSP-SPI changing with the ratio of GSP/SPI. At both lower concentration of GSP and SPI, Mixed GSP-SPI can form a GSP/SPI complex, which has synergistic effects. At both lower and higher ratio of GSP/SPI, The interfacial tension is similar value of each SPI and GSP at interface. It means that GSP and SPI are competitive adsorption relationships, which may control the adsorption behavior depending on the ratio of GSP/SPI at interface. Also, this might be useful for formation of suspension or emulsion food systems, if properly used, might in face widen them. The effect of ginseng saponin on the storage stability of soymilk was investigated at soymilk products. Soymilk was prepared according to general manufacturing process. And ginseng saponin powder (GSP) was added to soymilk at 0, 0.5, 1, 1.5, 2, 3%, w/w. Storage stability of soymilk was analyzed by examining: (1) shelf-life: pH value and microbial test, (2) storage stability: visual appearance, particle size distribution, and zeta potential, (3) rheological property during storage at 4, 25, and 37 °C stored 35 days. In case of shelf-life of soymilk, the pH value remained constant at pH 6.2-6.4. And microbial load was not detected. In case of storage stability of soymilk, the particle precipitation of soymilk decreased with increasing storage temperature, thereby the storage stability of soymilk was improved. It suggested that the soymilk particles, stored at lower temperature, have a larger electrostatic repulsive force according to the zeta potential results. Therefore, the particle aggregation of soymilk was inhibited during storage. In addition, according to the rheological properties of soymilk results, the soymilk showed a higher viscous behavior at lower storage temperature. It was expected that the precipitation rate of soymilk was decreased induced by Stokes law. Also, the soymilk showed a higher viscous behavior with increasing the GSP concentration. It was expected to be due to the increase in the total solid of soymilk or the formation of inter-molecular links, which is binding surfactant with micelle-several peptide. However, the addition of GSP had little effect on the storage stability of soymilk, including the particle precipitation and aggregation. This might be because soymilk is a complex system that contains high protein contents, many kinds of components. To understand the specific effect of ginsenoside on the storage stability of soymilk, additional experiments are necessary, such as making the soymilk suspension or/and emulsion model system that simplified the soymilk. This study systematically investigated the effects of various conditions (various GSP concentration and storage temperature) on storage stability of soymilk, and the interaction mechanism between ginsenoside and colloidal particles of soymilk at interface model system. It can help to explain the stabilization and storage stability of food dispersion model systems such as foams, emulsions, and its interface systems. Also, it can help to increase the utilization of soymilk processing and consumption as well as the food industrial utilization.Abstract ⅰ Contents ⅴ List of Tables ⅷ List of Figures ⅸ Chapter 1 Research background 1. Soybean nutritional values and soybean-based foods 1 2. Soymilk 2 2.1. Nutritional values and composition 2 2.2. Particle aggregation and precipitation during storage 4 2.3. Prevention methods of particle precipitation 6 2.3.1. Ultrahigh pressure homogenization process 6 2.3.2. Adding hydrocolloids 6 2.3.3. Adding surfactant as a new approach 8 3. Ginseng (Panax ginseng) saponin 8 3.1. Compositions and health functionality 8 3.2. Saponin as a natural surfactant 11 4. Overall objective 12 Chapter 2 Interfacial properties of ginseng saponin and soy protein isolate mixtures at air/water interface Introduction 13 Materials and Methods 14 1. Preparation of suspension 14 2. Interfacial tension measurement using wilhelmy plate method 15 Results and Discussion 15 1. Interfacial properties of ginseng saponin 16 1.1. Kinetics adsorption of saponin 16 1.2. Adsorption isotherm of saponin 17 2. Interfacial properties of soy protein isolate 18 2.1. Kinetics adsorption of protein 18 2.2. Adsorption isotherm of protein 18 3. Interfacial properties of mixed ginseng saponin and soy protein isolate 19 Conclusions 29 Chapter 3 Effects of ginseng (Panax ginseng) saponin on storage stability of soymilk Introduction 30 Materials and Methods 31 1. Soymilk elaboration 31 2. Shelf-life of soymilk 32 2.1. Microbiological test 32 2.2. pH 32 3. Storage stability of soymilk 33 3.1. Visual appearance 33 3.2. Particle size distribution 33 3.3. Zeta potential 33 4. Rheological properties of soymilk 33 Results and Discussion 34 1. Shelf-life of soymilk 34 2. Storage stability of soymilk 34 2.1. Visual appearance 35 2.2. Particle size distribution 35 2.3. Zeta potential 36 3. Rheological properties of soymilk 37 Conclusions 50 Overall conclusions 51 References 52 Abstract in Korean 60Maste

Protein-Protein Interactions among the hnRNPs Shuttling between the Nucleus and the Cytoplasm

Maste

압입시험을 이용한 박막의 계면 접착력 평가

학위논문 (박사)-- 서울대학교 대학원 : 공과대학 재료공학부, 2016. 2. 권동일.Recently materials are used to artificially bonding the different materials as a conventional single material. Since the interface that is artificially bonding of different materials, relatively weak section than the film and the substrate. So, the most preferentially failure occurs in a variety of external conditions. That is why the adhesion is regarded as the major property in determining the reliability of the product in a thin film system. The study was continued by many researchers to evaluate the quantitative adhesion for a long time, so that a variety of test methods have been developed. However, most of the conventional methods for evaluating adhesion, based on interfacial separation methods and interfacial fracture method, have limitations. There are three important issues in evaluating the quantitative value of adhesion: the first, effect of film/substrate deformation and fracture is important to the adhesion test results. so, it is necessary to re-interpret the results through the analysis of the film and substrate effect. Second, need to accurate measurement of the crack length and area for a few nanometer thickness film. And third, the applicable test method limited by the characteristics of the material. In the case of hard films, fracture or delamination of the film occurs before the interface. For the bending test, film or substrate should be a bending above certain level. In other words, evaluation for very soft materials is possible. In this thesis, in order to overcome the conventional testing method limitations, a new model proposed using the instrumented indentation test(IIT). Instrumented indentation testing (IIT) has recently attracted significant research interest in this connection, since its testing procedure is relatively simple and can be performed locally and above all high load- displacement resolution. Indentation testing at the thin-film system sample may also obtain a load-displacement curve that included the effect the combination of the thin film/substrate and the interface unlike Bulk sample testing. To interpret the load-displacement curve, "Total work of indentation" in the thin-film system was defined the sum of "work of film" and "work of substrate" and "work of adhesion". Using the formulated hardness, modeling for work of film and substrate plastic deformation effect at indentation test condition. Also, assume that relatively soft materials of plastic volume constraint by the hard materials. Constraint plastic zone volume of a relatively soft material by the interface was defined by the interface parameter. The interface parameter derived using the Expanding Cavity Model and interfacial constraint effect. Based on the previous analysis deriving the work of the adhesion excluding the film/substrate deformation effect. The work of adhesion varies with the experimental conditions, it was constraint volume normalization. Finally the adhesion evaluation method using the indentation test was proposed. To verify the validity of the proposed model, compared to indentation test and SAICAS test, a kind of peel test for metal/ceramic based thin film specimens. The results between two methods show good agreement. Those results show that indentation test is effective for estimation of thin-film adhesion.Chapter 1. Introduction 1 1.1. Objective of the Thesis 2 1.2. Organization of the Thesis 6 Chapter 2. Research Background 11 2.1. Adhesion evaluation method 12 2.1.1. True work of adhesion 12 2.1.2. Practical Work of Adhesion 14 2.2. Instrumented indentation tests 19 2.2.1. Elastic Contact mechanics 20 2.2.2. Elastic-Plastic Contact mechanics 26 2.3. Nanoindentation 35 2.3.1. Development 35 2.3.2. Application 40 Chapter 3. Theoretical Modeling 68 3.1. Thin-film indentation 69 3.2. Interfacial Constraint Effect 71 3.3. Interface parameter 76 3.4. Factor analysis 79 3.5. Modeling 81 3.5.1 Film constraint 82 3.5.2 Substrate constraint 83 3.6 Physical meaning of equation 85 Chapter 4. Verification of models 98 4.1. Experimental Details 99 4.1.1. Sample preparation 99 4.1.2. Experiment conditions 101 4.2. Results & Discussion 103 4.2.1. Comparison with SAICAS method 103 4.2.2. Analysis of indentation parameter 104 Chapter 5. Conclusion 120 Reference 126 Abstract in Korean (초록) 134Docto

Analysis of protein-protein interactions among heterogeneous nuclear ribonucleoproteins and their roles in IRES-dependent translation.

Docto

Moving vehicle identification using measured acceleration

학위논문(석사)--서울대학교 대학원 :건설환경공학부,2007.Maste

박판보의 좌굴해석

학위논문(석사)--서울대학교 대학원 :기계설계학과,1997.Maste

Molecular basis of stress-independent translation of HCV mRNA

2

Anti-HCV drug ribavirin inhibits HCV replication by reducing IRES activity

2

Polypyrimidine tract-binding protein enhances the IRES-dependent translation of p27Kip1 mRNA

1