characterization of antioxidant properties for dried organic fruits in turkish market and development

78 Pages·2014·1.52 MB·English

CHARACTERIZATION OF ANTIOXIDANT
PROPERTIES FOR DRIED ORGANIC FRUITS IN
TURKISH MARKET AND DEVELOPMENT OF
NOVEL STRATEGIES TO INCREASE THEIR
POTENTIAL HEALTH BENEFITS

A Thesis Submitted to
The Graduate School of Engineering and Sciences of
(cid:248)zmir Institute of Technology
in Partial Fulfillment of the Requirements for the Degree of

MASTER OF SCIENCE

in Biotechnology and Bioengineering

by
Gökhan DERV(cid:248)(cid:249)(cid:50)(cid:246)LU

December 2013
(cid:248)ZM(cid:248)R
We approve the thesis of Gökhan DERV(cid:248)(cid:249)(cid:50)(cid:246)LU

Examining Committee Members:

____________________________
Prof. Dr. Ahmet YEMEN(cid:248)(cid:38)(cid:248)(cid:50)(cid:246)LU
Department of Food Engineering, (cid:248)zmir Institute of Technology

____________________________
Prof. Dr. Talat YALÇIN
Department of Chemistry, (cid:248)zmir Institute of Technology

____________________________
Assoc. Prof. Dr. Figen KOREL
Department of Food Engineering, (cid:248)zmir Institute of Technology

____________________________
Assoc. Prof. Dr. Erol (cid:249)EKER
Department of Chemical Engineering, (cid:248)zmir Institute of Technology

____________________________
Assist. Prof. Dr. Beste BAYRAMO(cid:246)LU
Department of Food Engineering, (cid:248)zmir Institute of Technology

11 December 2013

______________ ______________
Prof. Dr. Ahmet YEMEN(cid:248)(cid:38)(cid:248)(cid:50)(cid:246)LU
Supervisor, Department of Food Engineering,
(cid:248)zmir Institute of Technology

_____________ _______________ ___________________________
Prof. Dr. Volga BULMU(cid:249) Prof. Dr. R. Tu(cid:247)rul SENGER
Head of the Department of Dean of the Graduate School of
Biotechnology and Bioengineering Engineering and Sciences
ACKNOWLEDGMENTS

I believe that this thesis enabling learning many things about academicianship
will carry me a step further in my academic career. Therefore, I would like to thank the
people who support me while writing this thesis.
First I would like to thank my advisor Prof. Dr. Ahmet YEMEN(cid:248)(cid:38)(cid:248)(cid:50)(cid:246)LU for
his continuous support, sharing his experience and knowledge generously.
I would like to thank the Assist. Prof. Dr. Bülent KAYA for his support and
understanding.
I would like to especially thank to my family being the most precious people in
the world for me, my parents Fatma and Ahmet DERV(cid:248)(cid:249)(cid:50)(cid:246)LU and my brother
Muhammet Murat DERV(cid:248)(cid:249)(cid:50)(cid:246)LU because of their self sacrifice, support,
encouragement, and understanding.
I would like to thank to Research Assistants (cid:248)skender ARCAN and Levent
Yurdaer AYDEM(cid:248)R for their support and sharing their knowledge.
Finally, I would like to thank sincerely to my dear, Züleyha TULAY for her
endless love and support, understanding, patience, friendship and encouragement.
ABSTRACT

CHARACTERIZATION OF ANTIOXIDANT PROPERTIES FOR
DRIED ORGANIC FRUITS IN TURKISH MARKET AND
DEVELOPMENT OF NOVEL STRATEGIES TO INCREASE THEIR
POTENTIAL HEALTH BENEFITS

In this thesis antioxidant parameters including trolox equivalent antioxidant
capacity (TEAC) and total phenolics (TPC) and flavonoid (TFC) contents of major
organic dried fruits (raisins, figs, prunes and apricots) produced in Turkey have been
determined to understand the bioactive potential of these products. Moreover, a novel
method based on controlled rehydration of specified dried fruits in phenolic extracts has
been developed to boost the phenolic content and antioxidant activity of dried fruits
with low bioactivity and potential health benefits. The TEAC, TPC and TFC of sun
dried fruits varied between 35.7 and 74.1 µmol trolox/g (d.w.), 1762 and 4062 µg gallic
acid/g (d.w.) and 830 and 2559 µg catechin/g (d.w.), respectively. The TEAC and TPC
of prunes were 1.7 to 2.3 fold higher than those for apricots, raisins and figs which
showed quite similar TEAC and TPC values. On the other hand, the TFC of prunes and
figs were similar and 1.7 to 3 fold higher than those of raisins and apricots. The
rehydration studies with raisins conducted in different concentrations (0.5% or 1%
(w/w)) of green tea extract (GTE) and walnut shell extract (WSE) at room temperature
until reaching of final moisture content of 38.73 % (w/w) showed the possibility of
increasing TEAC, TPF and TPC of raisins 1.6-1.8 fold. Similar rehydration strategy
applied to figs, prunes and apricots in 1% GTE to bring their moisture content to 39.83,
36.97 and 43.81 % respectively, caused 1.1-1.6 fold increase in TEAC, TPC and TFC of
these dried fruits. This work clearly showed the considerably higher bioactive potential
of organic dried prunes than organic dried raisins, figs and apricots. However, the
application of controlled rehydration process developed in this work enables increasing
antioxidant potential and phenolic contents of figs, raisins and apricots to the level of
prunes.

iv
ÖZET

TÜRK(cid:248)YE PAZARINDA BULUNAN ORGAN(cid:248)K KURUTULMU(cid:249)
MEYVELER(cid:248)N ANT(cid:248)OKS(cid:248)DANT ÖZELL(cid:248)KLER(cid:248)(cid:49)(cid:248)N
KARAKTER(cid:248)ZASYONU VE SA(cid:246)LIK ÜZER(cid:248)NDEK(cid:248) POTANS(cid:248)YEL
YARAYI(cid:249)LILIKLARININ ARTTIRILMASI (cid:248)(cid:100)(cid:248)N YEN(cid:248) STRATEJ(cid:248)LER
GEL(cid:248)(cid:249)(cid:55)(cid:248)(cid:53)(cid:248)LMES(cid:248)

Bu tez çal(cid:213)(cid:250)mas(cid:213)nda Türkiye’de üretilmekte olan ba(cid:250)(cid:79)(cid:213)ca organik kuru
meyvelerin (kuru üzüm, incir, erik ve kay(cid:213)(cid:86)(cid:213)) biyoaktif potansiyelinin belirlenmesi
amac(cid:213)yla bu ürünlerde troloks e(cid:250)de(cid:247)eri antioksidant aktivite (TEAC), toplam fenolik
madde (TPC) ve toplam flavonoit tayini (TFC) gerçekle(cid:250)tirilmi(cid:250)tir. Ayr(cid:213)ca, tezde
biyoaktivitesi dü(cid:250)ük olan kuru meyvelerin antioksidant fenolik çözeltiler içerisinde
rehidrasyonuna dayal(cid:213) yenilikçi bir yöntemle antioksidant aktivite ve fenolik madde
miktarlar(cid:213)(cid:81)(cid:213)n dolay(cid:213)(cid:86)(cid:213)yla sa(cid:247)(cid:79)(cid:213)(cid:247)a yaray(cid:213)(cid:250)(cid:79)(cid:213)(cid:79)(cid:213)klar(cid:213)(cid:81)(cid:213)n art(cid:213)(cid:85)(cid:213)lmas(cid:213) üzerinde de durulmu(cid:250)tur.
Gerçekle(cid:250)tirilen ölçümler kuru meyvelerin TEAC, TPC ve TFC gibi antioksidant
parametrelerinin s(cid:213)ras(cid:213)yla 35.7 ile 74.1 µmol trolox/g (d.w.), 1762 ile 4062 µg gallic
acid/g (d.w.) ve 830 ile 2559 µg catechin/g (d.w.) de(cid:247)erleri aras(cid:213)nda de(cid:247)(cid:76)(cid:250)ti(cid:247)ini
göstermi(cid:250)tir. Kuru eriklerin TEAC ve TPC de(cid:247)erleri bu parametrelerin ve dolay(cid:213)(cid:86)(cid:213)yla
antioksidant potensiyelin oldukça benzer oldu(cid:247)u üzüm, incir ve kay(cid:213)(cid:86)(cid:213)lardakinden 1.7
ile 3.0 kat kadar yüksek bulunmu(cid:250)tur. Kuru üzümlerin oda s(cid:213)cakl(cid:213)(cid:247)(cid:213)nda farkl(cid:213)
konsantrasyonda (%0.5 veya %1 (w/w)) ye(cid:250)il çay ekstrakt(cid:213) (GTE) veya ceviz kabu(cid:247)u
ekstrakt(cid:213) (WSE) içerisinde % 38.73 (w/w) neme ula(cid:250)acak (cid:250)ekilde rehidre edilmeleri
sonucunda TEAC, TPF ve TPC gibi parametreleri 1.6-1.8 kat art(cid:213)(cid:85)(cid:213)lm(cid:213)(cid:250)(cid:87)(cid:213)r. (cid:248)ncir, erik ve
kays(cid:213)larda ayn(cid:213) rehidrasyon prosedürünün %1 GTE içerisinde uygulanmas(cid:213) ve bu
ürünlerin nem de(cid:247)erlerinin s(cid:213)ras(cid:213)yla % 39.83, 36.97 ve 43.81 de(cid:247)erlerine getirilmesiyle
ise TEAC, TPC ve TFC de(cid:247)erlerinde 1.1-1.6 kat aras(cid:213)nda art(cid:213)(cid:250)lar sa(cid:247)lanabilmektedir.
Bu tez çal(cid:213)(cid:250)mas(cid:213) organik kuru eriklerin biyoaktif özelliklerinin kuru üzüm, incir ve
kay(cid:213)(cid:86)(cid:213)lara göre belirgin (cid:250)ekilde yüksek oldu(cid:247)unu göstermi(cid:250)tir. Ancak, bu tezde
geli(cid:250)tirilmi(cid:250) olan kontrollü rehidrasyon i(cid:250)lemiyle üzüm, incir ve kay(cid:213)(cid:86)(cid:213)lar(cid:213)n antioksidant
potensiyel ve fenolik madde miktarlar(cid:213)(cid:81)(cid:213)n eriklerinki düzeyine ç(cid:213)kart(cid:213)lmas(cid:213) mümkündür.

v
TABLE OF CONTENTS

LIST OF FIGURES ...................................................................................................... ix

LIST OF TABLES ....................................................................................................... xi

CHAPTER 1. INTRODUCTION ................................................................................. 1

CHAPTER 2. PHENOLIC SUBSTANCES .................................................................. 4
2.1. Nonflavonoid Phenolic Compounds ..................................................... 5
2.1.1. Phenolic Acids................................................................................... 5
2.1.2. Hydroxycinammates .......................................................................... 6
2.1.3. Stilbenes ............................................................................................ 7
2.2. Flavonoids ............................................................................................ 8
2.2.1. Flavones ............................................................................................ 9
2.2.2. Flavonols ......................................................................................... 10
2.2.3. Flavan-3-ols .................................................................................... 12
2.2.4. Flavanones ...................................................................................... 14
2.2.5. Anthocyanidins/Anthocyanins ......................................................... 15
2.2.6. Isoflavones ...................................................................................... 16
2.3. Biosynthesis of Phenolic compounds .................................................. 17
2.4. Antioxidant Mechanisms of Phenolic Compounds .............................. 22
2.4.1. Free radical scavenging ................................................................... 22
2.4.2. Metal chelating ................................................................................ 23
2.4.3. Singlet oxygen quenching ................................................................ 24
2.4.4. Photosensitizer inactivation ............................................................. 25
2.4.5. Lipoxygenase inactivation ............................................................... 25

CHAPTER 3. HEALTH BENEFITS OF PHENOLIC COMPOUNDS ........................ 27
3.1. Introduction ........................................................................................ 27
3.1.1. Antioxidant effects of phenolic compounds ..................................... 28
3.1.2. Bioavailability of polyphenols ......................................................... 30
vi
3.1.3. Cardio-protective effect of phenolic compounds .............................. 32
3.1.4. Anti-cancer effect of phenolic compounds ....................................... 35
3.1.5. Anti-aging effect of phenolic compounds ........................................ 38
3.1.6. Others .............................................................................................. 40

CHAPTER 4. MATERIALS AND METHODS........................................................... 42
4.1. Materials ............................................................................................ 42
4.2. Methods ............................................................................................. 43
4.2.1. Preparation of Phenolic Extracts Used In
Controlled Rehydration .................................................................. 43
4.2.1.1. Preparation of Green Tea Extracts................................................. 43
4.2.1.2. Preparation of Walnut Shell Extracts ............................................ 43
4.2.2. Controlled Rehydration of Dried Fruits ............................................ 43
4.2.3. Extraction of Phenolic compounds from dried fruits ........................ 44
4.2.3.1. Preparation of Dried Fruit Extracts Treated with
Green Tea/Walnut Shell .............................................................. 44
4.2.4. Preparation of Insoluble Fractions of Dried Fruits ............................ 45
4.2.5. Determination of Antioxidant potential of dried fruits ...................... 45
4.2.5.1. Determination of Total Phenolic Content of Dried Fruits .............. 45
4.2.5.2. Determination of Total Flavonoids Content of Dried Fruits........... 45
4.2.5.3. Determination of Free Radical Scavenging
Capacity (TEAC) of Dried Fruits ................................................. 46
4.2.5.4. Determination of Bound Antioxidant Activity............................... 46
4.2.5.5. Determination of The Moisture Content of
Dried Organic Fruits .................................................................... 47
4.2.6. Statistical Analysis .......................................................................... 47

CHAPTER 5. RESULTS AND DISCUSSIONS .......................................................... 48
5.1. Phenolic Content and Antioxidant Potential of
Major Organic Sun-Dried Fruits Grown in Turkey ............................. 48
5.2. Development of a Novel Controlled Rehydration
Method to Increase Phenolic Content and Antioxidant
Capacity of Sun-Dried Fruits .............................................................. 53

vii
5.2.1. Controlled Rehydration Studies with Raisins Using
Green Tea Extracts (GTE) and Walnut Shell Extracts (WSE) ........... 53
5.2.2. Controlled Rehydration Studies with
Prunes, Figs and Apricots Using Green Tea Extracts ........................ 58

CHAPTER 6. CONCLUSIONS .................................................................................. 63

REFERENCES............................................................................................................ 64
viii
LIST OF FIGURES

Figure Page
Figure 2.1. Chemical structures of polyphenols ............................................................. 4
Figure 2.2. Some phenolic acids found in plant foods .................................................... 5
Figure 2.3. Quinic acid structure .................................................................................... 6
Figure 2.4. Main chlorogenic acids in some plant foods. ................................................ 6
Figure 2.5. The trans- and cis- resveratrol and other stilbene structures. ......................... 7
Figure 2.6. Structures of the main flavonoid subgroups ................................................. 8
Figure 2.7. Structures of the chalcones and dihydrochalcones ........................................ 9
Figure 2.8. Mainly flavone structures ............................................................................ 9
Figure 2.9. Structures of four common flavonol aglycones
encountered in plant tissues ....................................................................... 10
Figure 2.10. Three characteristic flavonol glycosides illustrating
various combinations of sugar attachment on the flavonol skeleton ......... 11
Figure 2.11. Structures of flavan-3-ol .......................................................................... 13
Figure 2.12. Less common flavan-3-ol monomers ....................................................... 14
Figure 2.13. Mainly flavanones ................................................................................... 14
Figure 2.14. Basic structure of an anthocyanidin (flavylium cation) ............................. 15
Figure 2.15. Structures of the major anthocyanidins .................................................... 16
Figure 2.16. Structure of the isoflavones aglycones ..................................................... 17
Figure 2.17. The pathway of some phenolic compounds biosynthesis .......................... 18
Figure 2.18. The basic pathway of hydroxycinnamic acid
biosynthesis from phenylalanine ............................................................. 19
Figure 2.19. Hydroxybenzoic acids biosynthesis from hydroxycinnamic acid .............. 19
Figure 2.20. The structures of vanillin and vanillyl alcohol .......................................... 20
Figure 2.21. The synthesis of coumarin from cis-o-coumaric acid glucosides .............. 20
Figure 2.22. Flavonoid biosynthesis pathway .............................................................. 21
Figure 2.23. Antioxidant activity as a radical scavenger............................................... 23
Figure 2.24. Antioxidant radicals react with each other and alkyl peroxy radicals ........ 23
Figure 2.25. Radicals formation in the presence of metal ............................................. 24
Figure 2.26. Fundamentally the physical quenching mechanism .................................. 25
ix
Figure 3.1. Phenolic compounds as a antioxidant provide
protection from more than 50 severe diseases ............................................ 28
Figure 3.2. A representative model of balance of pro-oxidants / antioxidants ............... 29
Figure 3.3. The factors and substances that provide
ROS generation and prevention ................................................................. 29
Figure 3.4. Possible metabolism process of polyphenols .............................................. 31
Figure 3.5. Possible bioavailability ways of consumed
dietary polyphenols in humans .................................................................. 32
Figure 3.6. The incidence of different types of cancers that seen
in year of 2008 .......................................................................................... 35
Figure 3.7. The worldwide mortality rates in different cancer types
in 2008. ..................................................................................................... 36
Figure 3.8. Anticancer effects of phenolic compounds ................................................. 37
Figure 3.9. The common point of all these theories is the oxidative stress .......................... 39
Figure 3.10. The vicious respiratory cycle playing role in aging process ...................... 40
Figure 5.1. Total phenolic and flavonoid contents of different
controlled rehydrated organic dried fruits .................................................. 51
Figure 5.2. Total TEAC values of different controlled rehydrated
organic dried fruits .................................................................................... 52
Figure 5.3. Total phenolic and flavonoid contents of different
controlled rehydrated raisins using green tea extracts (GTE) and
walnut shell extracts (WSE) ...................................................................... 56
Figure 5.4. Total TEAC values of different controlled rehydrated raisins
using green tea extracts (GTE) and walnut shell extracts (WSE) ................ 57
Figure 5.5. Total phenolic and flavonoid contents of different controlled
rehydrated figs, prunes and apricots using green tea extracts ..................... 61
Figure 5.6. Total TEAC values of different controlled rehydrated
figs, prunes and apricots using green tea extracts ....................................... 62

x