| dc.contributor.advisor | Gökmen, Vural | |
| dc.contributor.author | Dönmez, Özge | |
| dc.date.accessioned | 2017-02-16T07:02:37Z | |
| dc.date.available | 2017-02-16T07:02:37Z | |
| dc.date.issued | 2017-01 | |
| dc.date.submitted | 2017-01-06 | |
| dc.identifier.citation | DÖNMEZ, Ö., EFFECT OF PROTEIN POLYPHENOL INTERACTION ON THE PHYSICOCHEMICAL PROPERTIES OF SET
TYPE YOGURT AND ON THE DIGESTIBILITY OF MILK PROTEINS, HACETTEPE UNIVERSITY OF GRADUATE SCHOOL OF SCIENCE AND ENGINEERING INSTITUTE, ANKARA, 2017. | tr_TR |
| dc.identifier.uri | http://hdl.handle.net/11655/3177 | |
| dc.description.abstract | The subject of protein-polyphenol interaction is of great interest to food science
because of causing the physicochemical changes in protein structure, which results
possibly in not only enhance the food product quality but also effect human health
in the presence of polyphenols. The main focus of this thesis was to reveal the
probable consequences of milk protein-polyphenol interactions in both the food and
simulated human gastrointestinal system.
In the first part, the effect of added different concentrations of green coffee powder
and green tea powder, as polyphenol sources, on syneresis behavior which is
described as a defect due to release serum phase from the gel matrix, and
consistency of set yogurts were investigated. The results showed that the interaction
between milk proteins and polyphenols improved the acid-induced gel network of
set yogurts as confirmed by decreased syneresis rate and increased consistency
during storage. But, green tea powder and green coffee powder behaved differently
as a concentration-dependent manner in acidified gel networks of set yogurt, modifying its rheological behavior, as they have different profiles and concentrations
of polyphenols.
In the second part, the effect of the interaction of the milk proteins beta-lactoglobulin
and micellar caseins (as micellar casein isolate) with either the polyphenol
epigallocatechin-3-gallate or alternatively with a polyphenol-rich green tea extract
on the modulation of protein digestibility promoted by gastrointestinal enzymes and
free radical scavenging capacity of phenolic compound was studied. The results
showed that the polyphenol binding is likely to alter protein structure leading to
increased protein stabilization through gastrointestinal tract. In addition, the free
radical scavenging capacity for polyphenols gradually decreased resulted in
interaction with protein, especially casein, from beginning to the end of the digestion. | tr_TR |
| dc.description.tableofcontents | CONTENTS
ABSTRACT .............................................................................................................. i
ÖZET ...................................................................................................................... iii
ACKNOWLEDGEMENTS........................................................................................ v
CONTENTS ............................................................................................................ vi
TABLE OF CONTENTS ......................................................................................... ix
LIST OF FIGURES .................................................................................................. x
SYMBOLS AND ABBREVATIONS ........................................................................ xii
INTRODUCTION .................................................................................................... 1
1. GENERAL INFORMATION ............................................................................. 2
1.1. Milk Proteins ............................................................................................. 2
1.2. Phenolic Compounds ............................................................................... 3
1.3. Interaction of Polyphenols with Proteins ................................................... 4
1.3.1. Interaction of Polyphenols with Whey Proteins .................................. 5
1.3.2. Interactions of Polyphenols with Caseins .......................................... 6
1.3.3. Role of the Milk Proteins-Polyphenols Interactions on Changes in
Gastroinetstinal Tract ................................................................................... 7
1.4. Fermented Milks-Yogurt ........................................................................... 9
1.4.1. One of the Quality Parameters of Yogurt Texture ‘Syneresis’ ......... 13
1.4.2. Rheological Characteristics of Yogurt .............................................. 14
2. SYNERESIS AND RHEOLOGICAL BEHAVIORS OF SET YOGURTS
COMPRISING GREEN TEA AND GREEN COFFEE POWDERS .................... 17
2.1. Introduction ............................................................................................ 17
2.2. Materials and Methods ........................................................................... 17
2.2.1. Chemicals and Consumables .......................................................... 17
2.2.2. Preparation of Green Tea and Green Coffee Powders as a Yogurt
Ingredients ................................................................................................. 18
2.2.3. Preparation of Yogurts Comprising GCP and GTP .......................... 18
2.2.4. Methods ........................................................................................... 18
2.2.5. Statistical Analyses .......................................................................... 20
2.3. Results and Discussion .......................................................................... 20
2.3.1. Syneresis Rate ................................................................................ 20
2.3.2. Rheological Behavior ....................................................................... 25
2.3.3. Changes in Color during Storage ..................................................... 29
2.4. Conclusion ............................................................................................. 29
3. MODULATION OF GASTROINTESTINAL DIGESTION FOR β-
LACTOGLOBULIN FOLLOWING BINDING BY (-)-EPIGALLOCATECHIN-3-
GALLATE (EGCG) AND GREEN TEA POLYPHENOLS .................................. 31
3.1. Introduction ............................................................................................ 31
3.2. Materials and Methods ........................................................................... 32
3.2.1. Chemicals and Consumables .......................................................... 32
3.2.2. Preparation of Green Tea Extract .................................................... 32
3.2.3. In-vitro Pepsin and Pancreatin Digestion ......................................... 32
3.3. Methods ................................................................................................. 33
3.3.1. Seperation of Protein and Nitroblue Tetrazolium Staining for
Quinoprotein Detection .............................................................................. 33
3.3.2. Isothermal Titration Calorimetry ....................................................... 33
3.3.3. Inhibition of Free Radical Scavenging (%) ....................................... 34
3.3.4. Statistical Analyses .......................................................................... 34
3.4. Results and Discussion .......................................................................... 35
3.4.1. Digestion Stability of Beta-Lactoglobulin .......................................... 35
viii
3.4.2. Digestion Stability of Micellar Caseins ............................................. 43
3.4.3. % Inhibition of Free Radical scavenging for Milk Protein-Polyphenol
Complexes ................................................................................................. 49
3.5. Conclusion ............................................................................................. 52
GENERAL CONCLUSION ................................................................................... 54
REFERENCES ..................................................................................................... 56
CURRICULUM VITAE .......................................................................................... 69 | tr_TR |
| dc.language.iso | en | tr_TR |
| dc.publisher | Fen Bilimleri Enstitüsü | tr_TR |
| dc.rights | info:eu-repo/semantics/restrictedAccess | tr_TR |
| dc.subject | Protein-polyphenol interaction | tr_en |
| dc.subject | Set yogurt | |
| dc.subject | Syneresis rate | |
| dc.subject | Rheological behavior | |
| dc.subject | Free radical scavenging capacity | |
| dc.subject | In-vitro digestion | |
| dc.title | Effect of Proteın Polyphenol Interaction on The Physicochemical Properties of Set Type Yogurt and on the Digestibility of Milk Proteins | tr_TR |
| dc.type | info:eu-repo/semantics/masterThesis | tr_TR |
| dc.description.ozet | Protein-polifenol interaksiyonu konusu, proteinin fizikiokimyasal özelliklerinde
meydana getirdiği değişim ile gıda ürünlerinde kalitenin iyileşmesi ve de polifenol
varlığında öngörülen insan sağlığı üzerindeki etkileri sebebiyle gıda bilimi için ilgi
çekici hale gelmektedir. Bu tezin ana odak noktası, süt proteinleri ile polifenoller
arasındaki etkileşimin hem gıda sisteminde hem de simüle edilmiş insan sindirim
sistemindeki muhtemel sonuçlarını ortaya koymaktır.
Birinci bölümde, polifenol kaynağı olarak farklı konsantrasyonlarda eklenen yeşil
çay tozu ve yeşil kahve tozunun set tipi yoğurtlarda, jel matrisinden serum fazının
salınması sonucu bir kusur olarak tanımlanan sineresis hızına ve akış davranışları
üzerine etkileri araştırılmıştır. Sonuçlar, süt proteinleri ile polifenoller arasındaki
interaksiyonun depolama sırasında sineresis hızındaki azalma ve kıvamdaki artışa
sebep olarak, asidifikasyonla meydana gelen yoğurt jel yapısını iyileştirdiğini
göstermektedir. Fakat, yeşil çay tozu ve yeşil kahve tozu yoğurt jelinin reolojik davranışını değiştirirken konsantrasyona bağlı farklı davranışlar sergilemişlerdir. Bu
durum farklı konsantrasyon ve tipte polifenollere sahip olmalarına bağlanmıştır.
İkinci bölümde, süt proteinlerinden beta-laktoglobulin ve kazein izolatı ile
epigallokateşin-3-gallat veya polifenolce zengin yeşil çay ekstraktı
interaksiyonunun, sindirim sırasında protein stabilitiesine ve fenollerin serbest
radikal yakalama kapasitesi üzerine etkisi incelenmiştir. Sonuçlar, polifenol
bağlanmasının protein yapısındaki muhtemel değişimi sonucu sindirim boyunca
protein stabilitesini arttırdığını göstermektedir. Ayrıca, özellikle kazeinle
interaksiyonun genel olarak sindirimin başından sonuna kadar fenollerin serbest
radikal yakalama kapasitesini düşürdüğünü göstermektedir. | tr_TR |
| dc.contributor.department | Gıda Mühendisliği | tr_TR |
