Detailed Information

Screening and Validation of Flavor-forming Starter Bacteria for Korean Gouda-type Cheese Model : 풍미 생산 스타터 박테리아의 선발 및 한국형 고다 타입 치즈 모델에서의 유효성 검증

DC Field Value Language
dc.description학위논문 (석사)-- 서울대학교 국제농업기술대학원 국제농업기술학과, 2017. 8. 허철성.-
dc.description.abstractLactic acid bacteria (LAB) have an important role in dairy fermentations, notably as cheese starter cultures. They cause not only rapid acidification and coagulant of milk through the production of lactic acid, but also flavor formation. Cheese flavor results from a complex combination of flavor compounds. The flavor compounds in cheeses are derived from milk composition which is mainly composed of lactose, milk casein, and milk fat. During cheese production and ripening period, various enzymes from milk, rennet, starter cultures, and non-starter LABs are involved in the flavor formation pathways-
dc.description.abstractglycolysis, proteolysis, and lipolysis. Among these three pathways, starter LABs are especially related into amino acids degradation, presumably the origin of major flavor compounds. Therefore, specific key enzymes (AdhE-
dc.description.abstractBifunctional Alcohol/Aldehyde dehydrogenase, BcaT-
dc.description.abstractBranched chain aminotransferase, AraT-
dc.description.abstractAromatic aminotransferase, EstA-
dc.description.abstractEsterase, Adh-
dc.description.abstractAlcohol dehydrogenase, CitP-
dc.description.abstractCitrate permease, KdcA-
dc.description.abstractKeto acid decarboxylase) appear to be major criteria for the selection of flavor-forming starter bacteria. By using the multiplex PCR assay for detection of genes for those enzymes, 44 of flavor-forming LAB strains were screened. Among them, the most putative strains which have a possibility to flavor formation in cheese were selected. They were four of Lactococcus lactis subsp. lactis strains and one of Lactococcus lactis subsp. cremoris strain. Each of five strains were further characterized and assessed for industrial use. The combinations of starter bacteria were validated in miniature Gouda-type cheese model. Flavor compounds of tested miniature cheeses were analyzed and profiled by using the Hercules Ⅱ electronic nose (Alpha M.O.S., France). Compared to industrial cheese starter (CHN-11, Chr.hansen, Denmark), selected flavor-forming starter bacteria showed more variety flavor profile. Methylbutanone and 1-propanol, 2-methyl- was only found in test groups. Among the test groups, flavor profile of Test 1 evolved most at the last day of ripening.-
dc.description.tableofcontentsAbstract ⅰ
Contents ⅲ
List of Tables ⅴ
List of Figures ⅵ

Chapter 1. Introduction 1
1.1. Study backgroud 1
1.2. Purpose of research 2

Chapter 2. Review of Literature 3
2.1. Cheese 3
2.1.1. Gouda-type cheese 4
2.2. Cheese starter culture 5
2.2.1. Starter lactic acid bacteria 5
2.2.2. Gouda-type cheese starter 6
2.3. Cheese flavor 7
2.3.1. Glycolysis of lactose and citrate 7
2.3.2. Proteolysis of milk casein 8
2.3.3. Lipolysis of milk fat 10
2.3.4. Gouda-type cheese flavor 11

Chapter 3. Material and Methods 13
3.1. Selection of the flavor-forming starter bacteria 13
3.1.1. Sample collection 13
3.1.2. Isolation of lactic acid bacteria 14
3.1.3. Acidification and coagulant activity 16
3.1.4. Proteolytic and lipolytic activity 16
3.1.5. Multiplex PCR 17
3.1.6. Enzymatic assay 21
3.2. Characterization of the selected starter bacteria 23
3.2.1. 16s rRNA sequence analysis 23
3.2.2. API test 24
3.2.3. Growth curve 24
3.2.4. Autolysis ability 25
3.2.5. Stability to freeze-drying process 26
3.3. Validation of the selected strains in cheese model 27
3.3.1. Manufacture of miniature cheese model 27
3.3.2. Electronic nose analysis 31

Chapter 4. Results 34
4.1. Selection of the flavor-forming starter bacteria 34
4.1.1. Isolation of lactic acid bacteria 34
4.1.2. Acidification and coagulant activity 34
4.1.3. Assessment of proteolysis and lipolysis 36
4.1.4. Detection of enzymes involved in the flavor-forming pathways 36
4.1.5. Glutamate dehydrogenase activity assessment 39
4.2. Characterization of the selected starter bacteria 40
4.2.1. Identification of the selected strains 40
4.2.2. Biochemichal property 40
4.2.3. Growth curve 42
4.2.4. Assessment of autolysis ability 44
4.2.5. Stability to freeze-drying process 45
4.3. Validation of the selected strains in cheese model 46
4.3.1. Analysis of miniature cheese model 46
4.3.2. Flavor compounds analysis 48 Discriminant Function Analysis (DFA) 48 Flavor compounds analysis 50

Chapter 5. Discussion 58

References 63

Abstract in Korean 75
dc.format.extent2219633 bytes-
dc.publisher서울대학교 국제농업기술대학원-
dc.subjectLactic acid bacteria-
dc.subjectStarter culture-
dc.subjectGouda cheese-
dc.titleScreening and Validation of Flavor-forming Starter Bacteria for Korean Gouda-type Cheese Model-
dc.title.alternative풍미 생산 스타터 박테리아의 선발 및 한국형 고다 타입 치즈 모델에서의 유효성 검증-
dc.contributor.AlternativeAuthorHye Won Lee-
dc.contributor.affiliation국제농업기술대학원 국제농업기술학과-
Appears in Collections:
Files in This Item:


Item View & Download Count

  • mendeley

Items in S-Space are protected by copyright, with all rights reserved, unless otherwise indicated.