Adrian Susanto

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PRESERVATION METHOD TO THE ALPHA-GLUCOSIDASE INHIBITORY ACTIVITY AND CHEMICAL CONTENTS

By

Adrian Susanto 11505039

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

July 2019

Revised after Thesis Defense on July 15^th 2019

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Adrian Susanto 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.

Adrian Susanto

__________________________________________ _____________

Student Date

Approved by:

Maria D.P.T. Gunawan Puteri, STP., M.Sc., Ph.D.

__________________________________________ _____________

Thesis Advisor Date

Nina Artanti, Ph.D.

__________________________________________ _____________

Thesis Co-Advisor Date

Dr.-Dipl.-Ing. Samuel P. Kusumocahyo

__________________________________________ _____________

Dean Date

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Adrian Susanto ABSTRACT

IMPACT OF LEMONGRASS (Cymbopogon citratus) EXTRACT PRESERVATION METHOD TO THE ALPHA-GLUCOSIDASE INHIBITORY ACTIVITY AND

CHEMICAL CONTENTS

By

Adrian Susanto

Maria D.P.T. Gunawan-Puteri, STP., M.Sc., Ph.D., Advisor Nina Artanti, Ph.D., Co-Advisor

SWISS GERMAN UNIVERSITY

Picking up from a foregoing study that promoted lemongrass extract as functional food in the form of an RTD drink, this study attempted to further increase the extract‟s value as functional food ingredient by increasing its shelf-life. Aqueous extract of lemongrass was subjected to several heat-oriented preservative treatments.

At tested extract concentration (15mg/mL), time/temperature of process specification appeared to be a critical parameter: spray-dried sample saw it inhibitory activity completely diminished. The extract‟s AGI activity - measured by rat intestinal sucrase inhibition assay - and microbial growth by total plate count method were observed throughout storage period and the former seemed to be highly affected by the latter.

Caffeic acid (CA), a compound that has been proposed as one of the compounds responsible for AGI activity in ethanolic extract, was also tested in this study.

However, CA was confirmed not to be the same major compound with only 3%

content in lemongrass water extract and its HPLC analysis was not relevant to the AGI activity.

Keywords: Cymbopogon citratus, Thermal Preservation, Alpha Glucosidase Inhibitor, Liquid Chromatography, Total Plate Count

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Adrian Susanto

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Adrian Susanto DEDICATION

For past me: may this be a reward and a remembrance for all that you‟ve been through For future me: may this be your pacemaker in times of needs

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Adrian Susanto ACKNOWLEDGEMENT

I wish to express my gratitude to my thesis advisor Maria D.P.T. Gunawan-Puteri, STP., M.Sc., Ph.D. who has been an enormous help to me ever since I first enter the SGU premise and for her everlasting faith in me and all her students even when the person themselves have lost all of their own. Also to my co-advisor Nina Artanti, Ph.D. to whom I have been nothing but a bother.

The same applies to my parents. I may not show it, but I love you 3000.

To those with special seats in my heart: Antonius Georgio, Cynthia Pukarta, Devina Andrea, Evelyn Antoinette, Gabriella Susanto, and Nattashya Febiola. I may not have been the best friend for you guys, but you all are for me. Special mention goes to Melvin Tandra.

To my AGI buddies Imelda Adhitama, Ivana Julisantika, and Nadia Krisanty for all the help and support – material and psychological.

To the unsung heroes kak Rizal Pauzan, mas Said Hudriyi, ci Stacia Fortunata, along with every SGU laboratory and office staff who have always tried their best to assist us thesis students. You are the best.

Also in memory of the temporarily unofficial sponsor of SGU LST Thesis 2019: S-tee, Teh kotak, and Tehbotol Sosro; thank you.

To my classmates, friends in and out of SGU, to those who have been a support, knowingly or not. I may not know what to say to you, but let me just say my thanks.

And finally for you: who have spent your time reading this book and this page in particular. I hope it helps.

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Adrian Susanto TABLE OF CONTENTS

STATEMENT BY THE AUTHOR ... 2

ABSTRACT ... 3

DEDICATION ... 5

ACKNOWLEDGEMENT ... 6

TABLE OF CONTENTS ... 7

TABLE OF FIGURES ... 9

LIST OF TABLES ... 10

CHAPTER 1 - INTRODUCTION ... 11

1.1 Background ... 11

1.2 Research Objectives ... 12

1.3 Significance of Study ... 13

1.4 Research Questions ... 13

1.5 Hypothesis ... 13

CHAPTER 2 - LITERATURE REVIEW ... 14

2.1. Alpha Glucosidase Inhibitors as Diabetic Treatment ... 14

2.2. Lemongrass ... 16

2.3. Trends in Functional Food Development ... 18

2.4. Beverage Processing ... 19

CHAPTER 3 - RESEARCH METHODS ... 20

3.1 Venue and Time ... 20

3.2 Material and Equipments ... 20

3.3 Design of Experiments ... 21

3.4 Experimental Procedure ... 22

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Adrian Susanto

3.4.2. Water-Based Lemongrass Extraction and Extract Preservation ... 22

3.4.3. Spray-drying Process ... 22

3.5 Analytical Procedure ... 23

3.5.1. Rat Intestinal Sucrase Inhibitory Assay ... 23

3.5.2. Total Soluble Solid Content Quantification ... 25

3.5.3. Caffeic acid identification ... 25

3.5.4. Microbial Growth Assessment ... 26

CHAPTER 4 - RESULTS AND DISCUSSIONS ... 27

4.1 Pre-Extraction Treatment of Lemongrass Ingredient ... 27

4.2 Confirmation of Bioactive Compound of Lemongrass Aqueous Extract ... 32

4.3 Effect of Various Preservative Treatments on the Lemongrass Extract ... 35

4.3.1. Effect on AGI inhibitory activity ... 35

4.3.2. Effect on caffeic acid content ... 36

4.3.3. Effect on physical characteristics ... 39

4.4 Changes in the Lemongrass Extract throughout Observation Period ... 41

4.4.1 Changes in terms of AGI activity ... 41

4.4.2. Changes in terms of microbial growth ... 43

4.4.3 Correlation between the two changes ... 47

CHAPTER 5 - CONCLUSIONS AND RECOMMENDATIONS ... 48

REFERENCES ... 50