By Amanda Celina
11405012
BACHELOR’S DEGREE in
FOOD TECHNOLOGY
FACULTY OF LIFE SCIENCES AND TECHNOLOGY
SWISS GERMAN UNIVERSITY The Prominence Tower
Jalan Jalur Sutera Barat No. 15, Alam Sutera Tangerang, Banten 15143 - Indonesia
August 2018
Revision after Thesis Defense on July 25, 2018
Amanda Celina 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.
Amanda Celina
_____________________________________________
Student Date
Revision after Thesis Defense on July 25, 2018
Approved by:
Della Rahmawati, S.Si., M.Si.
_____________________________________________
Thesis Advisor
Date
Tabligh Permana, S.Si., M.Si.
_____________________________________________
Thesis Co-Advisor Date
Dr. Dipl. –Ing. Samuel P. Kusumocahyo
_____________________________________________
Dean Date
Amanda Celina APPLICATION OF LEMONGRASS ESSENTIAL OIL
AS A NATURAL PRESERVATIVE AGENT FOR PINEAPPLE JUICE
By Amanda Celina
Della Rahmawati, S.Si., M.Si., Advisor Tabligh Permana, S.Si., M.Si., Co-Advisor
SWISS GERMAN UNIVERSITY
Pineapple juice is frequently consumed for its extensive health benefits, but is prone to microbiological degradation. Pasteurization – as a current preservation technique – have degraded nutritional quality of fruit juices and the use of synthetic preservatives have been perceived negatively by consumers. In this study, lemongrass essential oil was applied for the preservation of pineapple juice. Well diffusion was used for antimicrobial activity screening of lemongrass essential oil against E. coli, S. cerevisiae, and A. niger, while broth macrodilution method was used in determining MIC of lemongrass essential oil, which was evaluated to be 0.1%. Furthermore, the addition of 0.1% lemongrass essential oil into pineapple juice had a negative effect regarding the sensorial acceptability, but was able to significantly suppress the microbial count for bacteria, yeast, and mould during 5 days of storage time in chilling temperature (4ºC).
Vitamin C content degradation and pH changes during storage were not significantly affected by the addition of lemongrass essential oil. Furthermore, the addition of 0.1%
lemongrass essential oil was observed to be not synergistic with the enzyme activity of pineapple juice, and has negatively impacted the enzyme stability of the pineapple juice.
Keywords: antimicrobial, Cymbopogon citratus, essential oil, Ananas comosus, preservative, storage stability
Amanda Celina
© Copyright 2018 by Amanda Celina All rights reserved
Amanda Celina I dedicate this work to my family.
Amanda Celina ACKNOWLEDGEMENTS
First of all, I would like to thank God for His never-ending blessing towards me. I am exceptionally grateful for the way He guides my thoughts and actions throughout the thesis work, and for making everything possible in the first place.
Secondly, I would like to thank Ms. Della Rahmawati as my thesis advisor, Mr. Tabligh Permana as my thesis co-advisor, and Ms. Maria D. P. T. Gunawan Puteri for giving me countless valuable knowledge and guidance throughout the thesis work.
My utmost gratitude goes to Ms. Rara Purwanty, Mr. Gerald Justin Goenawan, Ms.
Pratiwi Andayani, and Mr. Roziq as lab assistants who took care of each of us very well in the laboratory. I am grateful for their kindness, their warmth, and their company. I want to thank them also for sharing their knowledge, for constantly guiding me, and for the helping hands throughout the thesis work.
My acknowledgment goes to Vimothy Daniel Montolalu for being exceptionally encouraging and for being able to keep up with my struggles during the thesis period. I would also like to thank Rebecca Wirawan for constantly being a wonderful friend who shares an awful lot in common with me, Joshua Wijaya for being a caring individual as well as a great listener, and Gabriella Putri Gunawan for being incredibly helpful in the laboratory. I would also like to express my gratitude to my friends from the University, especially my Food Technology 8 classmates for sharing their thesis work experiences to me, for the helping hands, and for being such great individuals during these four months of exhausting yet challenging thesis period.
Last but not least, I would like to express my appreciation to my family, for supporting me mentally and financially, for always including me in their prayers, and for always being there whenever I needed them. I could not have done it without them.
Amanda Celina Page
STATEMENT BY THE AUTHOR ... 2
ABSTRACT ... 3
DEDICATION ... 5
ACKNOWLEDGEMENTS ... 6
TABLE OF CONTENTS ... 7
LIST OF FIGURES ... 10
CHAPTER 1 – INTRODUCTION ... 12
Background ... 12
Research Problems ... 14
Research Objectives ... 14
Significance of Study ... 15
Research Questions ... 15
Hypotheses ... 16
CHAPTER 2 – LITERATURE REVIEW ... 17
Pineapple Juice ... 17
Pineapple Juice Processing ... 17
Microbial Contamination in Pineapple Juice ... 19
Preservation Techniques ... 20
Thermal Treatment ... 20
Addition of Synthetic Preservatives ... 21
Essential Oil ... 22
Lemongrass Essential Oil ... 23
Antimicrobial Activity of Lemongrass Essential Oil ... 25
CHAPTER 3 – RESEARCH METHODS ... 27
Venue and Time ... 27
Materials and Equipment ... 27
Materials ... 27
Equipment ... 27
Amanda Celina Preliminary Analysis of Lemongrass Essential Oil and Pineapple
Juice ... 29
Determination of Essential Oil Concentration ... 29
Shelf Life Analysis ... 29
Experimental Procedure ... 30
Production of Pineapple Juice Samples ... 30
Analytical Procedure ... 30
pH Measurement ... 31
Vitamin C Content Analysis ... 31
Enzyme Activity Analysis ... 32
Agar Well Diffusion Method ... 33
3.5.4.1 Agar Well Diffusion Method for Bacteria ... 34
3.5.4.2 Agar Well Diffusion Method for Yeast ... 34
3.5.4.3 Agar Well Diffusion Method for Mould ... 35
Minimum Inhibitory Concentration (MIC) Determination ... 36
3.5.5.1 Broth Macrodilution for Bacteria ... 36
3.5.5.2 Broth Macrodilution for Yeast ... 37
3.5.5.3 Broth Macrodilution for Mould ... 38
Total Plate Count ... 39
Total Yeast and Mould Count ... 40
Hedonic Scale Sensory Evaluation ... 41
Shelf Life Analysis ... 41
CHAPTER 4 – RESULTS AND DISCUSSIONS ... 43
Pineapple Juice Preparation and Analysis ... 43
Well Diffusion Method Results for Lemongrass Essential Oil ... 44
Minimum Inhibitory Concentration Determination of Lemongrass Essential Oil ... 48
Sensory Evaluation Results ... 52
Shelf Life Analysis of Pineapple Juice ... 54
Total Plate Count ... 54
Total Yeast and Mould Count ... 56
Amanda Celina
CHAPTER 5 – CONCLUSIONS AND RECCOMENDATIONS ... 63
Conclusions ... 63
Recommendations ... 64
GLOSSARY ... 65
REFERENCE ... 66
APPENDIX ... 72
CURRICULUM VITAE ... 96
