Use of pineapple juice for inhibition of browning in apples

100 Pages·2011·0.84 MB·English

AN ABSTRACT OF THE THESIS OF
Patricia Lozano-de-Gonzalez for the degree of Doctor of Philosophy
in Food Science and Technology presented on December 12. 1991
Title: Use of Pineapple Juice for Inhibition of Browning in Apples.
Abstract approved: ,, - -- . . - - .
D. Barrett
Two studies were conducted to evaluate the potential of
pineapple juice as an inhibitor of enzymic browning in processed
apple products and to detemine what pineapple juice
components accounted for the inhibition of browning. In the
first study, three separate experiments were carried out, two
with 'Red Delicious' and one with 'Granny Smith' apples. 'Red
Delicious apples were used for fresh apple ring product and
'Granny Smith' for dried apple ring products. In general,
pineapple juice proved to be as good as sulfite inhibiting the
browning of the rings for both fresh and dried products.
In a second study the pineapple juice was fractionated and
each fraction was tested on apple crude extract for
polyphenoloxidase activity. All the fractions tested inhibited the
enzymatic browning of crude apple extract by at least 26%. A
cation exchange fraction of the pineapple juice caused 100%
inhibition for at least 12 hours. This value was significantly
different from the rest of the fractions. Two other fractions (an
anion exchange fraction and a ultrafiltered cation exchange
fraction) caused approximately from 50 to 55% inhibition.
Use of Pineapple Juice for Inhibition of Browning in Apples
by
Patricia Lozano-de-Gonzalez
A THESIS
submitted to
Oregon State University
in partial fulfillment of
the requirements for the
degree of
Doctor of Philosophy
December 12, 1991
Commencement June 1992
APPROVED:
Assistant Professor of Food Science and Technology in charge of
major
f
-7* ■ / = f -ftrvr.^L-a
Heau Department of Food Science and Technology
Dean of Graduate SchcJp,
Date thesis is presented 12/12/91
Typed by Patricia Lozano-de-Gonzalez
ACKNOWLEDGMENTS
First, I would like to thank God for giving me health, strength
and an open mind to complete my degree.
I would like to express my gratitude to Dr. Diane Barrett and Dr.
Ronald Wrolstad, my advisors, for the valuable help I received from
them during the time that I was doing this project. I also want to
thank Dr. Dale Moss, Dr. Lorraine Miller and Dr. Sonia Anderson, for
being in my Graduate Committee and for their interest, suggestions
and encouragement.
Acknowledgment is due to the Dole Company for their interest
in this project and for their supply of pineapple juice concentrate.
To the Mid-Columbia Research and Extension Center in Hood River,
Oregon, for the apples provided. Also to W.R. Grace and Company,
for the Cryovac Bags supplied.
Special thanks to Bob Durst for the great help and ideas in the
laboratory. I also appreciate the help of Alfonso Gardea, my
compadre, for the advice on the Statistical Analyses. Thanks are
extended to the Faculty, Staff and Graduate Students in the Food
Science and Technology Department at Oregon State University, and
to my friends outside the department for their help, comments and
support during the realization of this thesis. My special thanks and
love to my parents, sisters and brothers for their support and
encouragement.
Finally, I dedicate this thesis to my husband, Carlos and my
daugther, Karla. I greatly appreciate their support, patience and
immense love.
TABLE OF CONTENTS
Page
Literature Review 1
Polyphenoloxidase 1
Characteristics of PPO 4
Optimum pH and Temperature 5
Extraction of PPO 6
Active Site and Copper 7
Polyphenoloxidase Assay 7
Prevention of Enzymatic Browning 8
a) Chelating agents 9
b) Molecules that interact with products
in the chain or substrates 12
c) Lowering pH 18
d) Excluding oxygen 18
e) Blanching 19
Use of Inhibitors in the Food Industry 19
Pineapple 21
Evaluation of color differences 22
References 27
II. The Effect of Pineapple Juice on Inhibition of
Browning in Apple Rings 36
Introduction 37
Materials and Methods 39
Results and Discusssion 49
References 58
III. Inhibition of Apple Browning by Pineapple Juice
Fractions 60
Introduction 61
Materials and Methods 64
Results and Discussion 69
References 79
IV. Bibliography 81
LIST OF FIGURES
Page
Figure 1. Changes in L* in 'Red Delicious'
fresh apple rings 54
Figure 2. Visual panel scores for vacuum-
packed fresh apple rings 55
Figure 3. Fractionation of pineapple juice 68
Figure 4. Percent inhibition of enzymic
browning by pineapple juice
fractions 76
LIST OF TABLES
Page
Table 1. Composition of dip treatments 44
Table 2. Experiments performed on the apple
rings 45
Table 3. Effect of various treatments on
inhibition of browning in fresh
apple 'Red Delicious' apple rings 56
Table 4. Changes in L* value of 'Granny Smith'
dried apple rings 57
Table 5. Composition of pineapple juice
fractions 77
Table 6. Percent inhibition of browning by
pineapple juice fractions 78
Use of Pineapple Juice for Inhibition of Browning in Apples
I. Literature Review
Polyphenoloxidase
Polyphenoloxidase (PPO), belongs to the group of
oxidoreductases. It has been given many names, including
tyrosinase, phenolase, catechol oxidase, o-diphenol oxidase, and
cresolase. Lacasse, which also falls under the name of
polyphenoloxidase, differs from o-diphenol oxidase in substrate
specificity (Vamos-Vigyazo, 1981). In this review, PPO will refer
exclusively to o-diphenol oxidase.
PPO is widely distributed in nature. In addition to its general
occurrence in plants, it can also be found in microorganisms,
especially fungi, and some animal organs (Labuza and Schmidl,
1986). It has been detected in most known fruits and vegetables.
The content of PPO in different plants varies widely with the
species. The enzyme localization in the plant cell depends on the
cultivar, age and in the case of fruits and vegetables, on maturity.
In freshly harvested apples, the enzyme has been found to be
localized almost exclusively in chloroplasts and mitochondria
(Vamos Vigyazo, 1981). The international nomenclature refers to