APPLICATION OF CITRUS ESSENTIAL OIL IN EDIBLE COATING TO DELAY FRESH TOFU DEGRADATION
By Mega Chandra
14212056
BACHELOR’S DEGREE in
FOOD TECHNOLOGY LIFE SCIENCES & TECHNOLOGY
SWISS GERMAN UNIVERSITY EduTown BSD City
Tangerang 15339 Indonesia
STATEMENT BY THE AUTHOR
I hereby declare that this submission is my own work and to the best of my knowledge, it contains no material previously published or written by another person, nor material which to a substantial extent has been accepted for the award of any other degree or diploma at any educational institution, except where due acknowledgement is made in the thesis.
Mega Chandra
____________________________________________
Student Date
Approved by:
Maria D.P.T Gunawan Puteri, S.TP., M.Sc., Ph.D ____________________________________________
Thesis Advisor Date
Della Rahmawati, S.Si, M.Si.
____________________________________________
Thesis Co-Advisor Date
Dr. Dipl-Ing. Samuel P. Kusumocahyo
____________________________________________
Dean Date
ABSTRACT
APPLICATION OF CITRUS ESSENTIAL OIL IN EDIBLE COATING TO DELAY FRESH TOFU DEGRADATION
By Mega Chandra
Maria Gunawan Puteri D.P.T, S.TP., M.Sc., Ph.D, Advisor Della Rahmawati, S.Si, M.Si, Co-Advisor
SWISS GERMAN UNIVERSITY
The purpose of this research was to delay the degradation of tofu by utilizing citrus essential oil as natural antimicrobial agent, with edible coating as intermediate media. The commercial essential oil of Citrus limon, Citrus sinensis and Citrus aurantifolia from Semarang, West Java Indonesia extracted by steam distillation was used. Two kinds polymers which were starch based and alginate based were analysed. Alginate based coating solution was chosen due to its better gelation and retention of tofu characteristics. A set of solution of Sodium Alginate 1.29%(w/v), glycerol 1.16% (w/v), 0.025%(w/v) sunflower oil and 0.6% (v/v) citrus limon essential oil and 2%(w/v) Calcium Chloride was used as coating system for fresh tofu. The minimum inhibition concentration (MIC) of Citrus limon essential oil was 0.2% and 0.6%, and minimum bactericidal concentration (MB) was determined 0.6% and >2% against Bacillus sp., and Escherichia coli, respectively. Single-layer coating was chosen for coating application. A batch of control negative, control positive and sample underwent degradation test of 12-hour interval for 48 hours. They were analysed chemically and microbiologically. It was observed that C. limon essential oil can act as a good antimicrobial activity against bacteria, and alginate can act as a good based edible coating solution for bacteria-prone food such as tofu.
© Copyright 2016 by Mega Chandra All rights reserved
DEDICATION
I dedicate this works for the people who has given me their infinite support
ACKNOWLEDGEMENTS
This piece of hard-work and dedication would not happen without no-ending supports, faith, guidance and patience from all of the parties.
To almighty God, for His unlimited Grace.
To my family who has support me throughout the journey
To my thesis advisor, Mrs. Maria D.P.T. Gunawan Puteri, S. Tp., M.Sc., Ph. D and co- advisor, Della Rachmawati, S.Si., M.Si., thank you for your kind advised, support, guidance, and simultaneous attention. I cannot thank you enough for sparing all of your busy time.
To Mr. Irvan Kartawira, ST., Ms. C, Mr. Tabligh Permana who have helped me during hard-times in completing this thesis
To my important people who have been there through hard and good times, Riswandi Wansyah, Giacinta Beta, Leah Sibuyo, Hamdarian Wijaya, Paula Felycia, Raissa Melina and Ria Isnaeni.
To all of my friends who cannot be name one by one, those who was there through stressful times, late night laboratory overtime, and helps through thesis writing. Words cannot explain enough how much fun, care and patient I have received.
To all Lecturers and staffs who had taught me everything from the very beginning until now reaching the end of this study.
TABLE OF CONTENTS
STATEMENT BY THE AUTHOR ... 2
ABSTRACT ... 3
DEDICATION ... 5
ACKNOWLEDGEMENTS ... 6
CHAPTER 1 - INTRODUCTION ... 12
1.1. Background ... 12
1.2. Research Problems ... 13
1.3. Objectives ... 14
1.4. Significance Studies ... 14
1.5. Research Question ... 14
1.6. Hypothesis ... 15
CHAPTER 2 - LITERATURE REVIEW ... 16
2.1 Tofu ... 16
2.1.1 Microbial Spoilage of Tofu ... 17
2.1.2 Chemical Preservatives in Tofu ... 18
2.2 Edible Coating ... 18
2.2.1. Starch based Edible Coating ... 19
2.2.2. Alginate based Edible Coating ... 20
2.2.3. Glycerol as Plasticizer ... 22
2.2.4. Incorporation of Active Compounds in Edible Coating ... 24
2.3.1. Antimicrobial Activity of Citrus Components ... 25
CHAPTER 3 – RESEARCH METHODS ... 28
3.1. Venue and Time ... 28
3.2. Materials and Equipment ... 28
3.2.1. Materials ... 28
3.2.2. Equipments ... 28
3.3. Design of Experiments ... 29
3.3.1. Determination of Appropriate Edible Coating ... 30
3.3.2. Selection of Essential Oil Type and Concentration ... 30
3.3.3. Incorporation of Citrus Essential Oil in Edible Coating for Tofu Application 31 3.4. Experimental Procedure ... 32
3.5.1. Physicochemical Analysis ... 34
3.5.1.1. Viscosity ... 34
3.5.1.2. Density ... 34
3.5.1.3. Basis Weight ... 35
3.5.1.4. Microscope Measurement ... 35
3.5.2. Microbial Analysis ... 35
3.5.2.1. Minimum Inhibitory Concentration ... 35
3.5.2.2. Minimum Bactericidal Concentration... 36
3.5.2.3. Total Plate Count ... 36
3.5.3. Chemical Analysis for Tofu ... 37
3.5.3.1. Moisture Content ... 37
3.5.3.2. pH Measurement ... 37
3.5.3.3. Protein Content Analysis... 37
CHAPTER 4 – RESULTS AND DISCUSSIONS ... 39
4.1. Determination of Appropriate Edible Coating based Materials ... 39
4.1.1. Physicochemical Properties of Edible Coating Solution ... 39
4.1.2. Thickness Measurement of Alginate Edible Coating ... 41
4.2. Selection of Essential Oil Types, Concentration and Methodology of Application ... 42
4.2.1. Minimum Inhibitory Concentration ... 43
4.2.2. Minimum Bactericidal Concentration ... 46
4.2.3. Method of Essential Oil Application ... 48
4.3. Incorporation of Citrus Essential Oil in Edible Coating for Tofu Application 50 4.3.1. Microbial Spoilage ... 50
4.3.2. Moisture Content Analysis ... 51
4.3.3. Protein Content Analysis ... 53
4.3.4. Acidity Analysis ... 55
4.3.5. Degradation Rate Analysis ... 58
4.3.6. Sensory Analysis ... 59
CHAPTER 5 – CONCLUSIONS AND RECOMMENDATIONS ... 61
5.1. Conclusions ... 61
5.2. Recommendations ... 61
REFERENCES ... 62
APPENDIX ... 67
CURRICULUM VITAE ... 89