Table Of ContentFACTORS AFFECTING- REACTIVATION OF ENZYMES
A Thesis
Presented to
th e Faculty of the Department of B acteriology
The U niversity of Southern C alifo rn ia
In P a rtia l F ulfillm en t
of the Requirements fo r the Degree
M aster of Science in B acteriology
by
W illiam Jack Marenus
January 1951
UMI Number: EPG5021
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This thesis, written by
......................
under the guidance of hX&...Facuity Committee,
and approved by all its members, has been
presented to and accepted by the Council on
Graduate Study and Research in partial fulfill
ment of the requirements for the degree of
M aster of Science
.P.ep.ar.tme.nt...of...BacterlQlo.gy.
Date.....
Faculty Committee
ACKNOWLEDGMENTS
I am indebted to Dr* M. D* Appleman fo r suggesting
the problem and giving assistan ce in i t s com pletion.
TABLE OF CONTENTS
CHAPTER PAGE
I. INTRODUCTION . ......................................................................... 1
A REVIEW OF SOME OF THE LITERATURE
CONCERNING ENZYME REGENERATION..................... 1
II* THE RELATIONSHIP OF PEROXIDASE REGENERATION
TO REDOX POTENTIAL IN HEATED AND UNHEATED
WATER INFUSIONS OF GREEN BEANS STORED AT
~10°C. AND 20°c:; . ♦ .......................................... 11
Purpose • • • . • • • • • • • • • • • • • 11
Method • • • • • • • » . 12
R esults • • • • • • • • • ..........................* • 14
D iscussion and Conclusions • • ......................... 15
Summary . ..................... • 18
I I I . THE EFFECT OF OXIDIZING AND REDUCING AGENTS
ON ACTIVITY AND REGENERATION OF CAULIFLOWER
PEROXIDASE ........................................ 24
In trod uctio n • • • • • • • • • • • » . • • 24
Method • • • • • • • .................................... . . . 24
R esults • • • • • « • • . • • • • • • • • 29
D iscussion and Conclusions • • • • • • • • 30
Summary • • • • • * • • • « • • • • • • . 33
IV. THE EFFECT OF OXIDIZING AGENTS ON THE
OXIDATION REDUCTION POTENTIAL AND ACTIVITY
CHAPTER PAGE
OF CAULIFLOWER PEROXIDASE . . . . . . . . 36
Intro d u ctio n • • • • • • • • • • • • • « * 36
Method .............................................................. 37
R esults .......................... . . . . . . . 33
D iscussion and Conclusions • • • • • • • • 40
Summary • • • • • « • • • • • • • • • • • 43
V. THE EFFECT OF BOILEDP EROXIDASE EXTRACT ON
OXIDIZED GUAIACOL 46
Intro d u ctio n • • • • • • • • • » • * • • < • 46
Method • • • • « » • * • • • • • • • » • • 46
v
R esults • • • • • • » • • • • • • • • * « 47
D iscussion and Conclusions • • • • • • • • 48
Summary * • • • • • • • • * • • • » • • • 50
VI. GENERAL SUMMARY ANDC ONCLUSIONS 51
BIBLIOGRAPHY........................................ . . . 55
LIST OF TABLES
TABLE PAGE
I* Peroxidase A c tiv ity as Influenced by ;
O xidizing and Reducing Agents » . * • • • • 34
II* O xidation R eduction P o te n tia l as Influenced
by O xidizing and Reducing Agents • • • • ♦ 35
III# E ffect of O xidizing Agents on Peroxidase
A ctiv ity ..................... 44
IV. E ffect of O xidizing Agents on O xidation
Reduction P o te n tia l ............................... * • • • • 45
LIST OF FIGURES
FIGURE PAGE
1. O xidation Reduction P o te n tia l and Peroxidase
A ctiv ity in Unheated Green Bean Infusion
Stored a t 20°C* *• • •. 20
2* O xidation Reduction P o te n tia l and Peroxidase
A ctiv ity in Unheated Green Bean Infusion
Stored at -10°C. • * « • • • « • • • • * * 21
3* O xidation Reduction P o te n tia l and Peroxidase
A ctiv ity in Green Bean Infusion Heated to
70°C* fo r th ir ty m inutes and Stored at
20° G...................................... 22
4.. O xidation Reduction P o te n tia l and Peroxidase
A ctiv ity in Green Bean Infusion Heated to
70°C# fo r th ir ty m inutes and Stored at
CHAPTER I
INTRODUCTION
A REVIEW OF SOME OF THE LITERATURE CONCERNING
ENZYME REGENERATION
Foods processed by freezin g re ta in more of th e ir
fresh flav o r and n u tritio n a l values than canned, d ried ,
and smoked foods* For th ese reasons, th is type of food
is form ing an ev er-in creasin g p art of th e d ie t of the
nation*
Many new problems have appeared w ith th is type of
process, fo r the botulinum cook is omitted* The food,
though i t is handled c arefu lly and blanched may s t i l l
contain b a c te ria th a t cause spoilage and c e rta in enzymes
th a t are e ith e r not com pletely in ac tiv a te d or th a t have
become reactivated* T herefore, i t is necessary to prevent
frozen food from thawing fo r spoilage is rapid upon
defrosting*
This paper concerns its e lf w ith the re a c tiv a tio n
of enzymes a fte r th e ir apparent d estru ctio n during
blanching*
Freezing a c ts on unblanched vegetable tis s u e in a
manner sim ila r to b ru isin g w ith th e form ation of o ff
ta s te s and odors* These ta s te s and odors are said by
Joslyn (19^9) to be due to th e form ation of sm all amounts
of v o la tile compounds whose nature is unknown. Joslyn also
fe e ls th a t these compounds are formed in the frozen
vegetable tis s u e because the enzyme systems are disrupted#
This d isru p tio n , which re s u lts in an accum ulation of
in term ediates, not norm ally p resen t, may occur w ith lowered
tem perature because the tem perature c o e ffic ie n ts of c e rta in
enzyme systems vary sig n ific a n tly .
Blanching, fo r th e purpose of destroying enzymes
was introduced early in th e h isto ry of the frozen food
in d u stry , fo r i t was made evident by food spoilage th a t
enzymes were activ e even at freezing tem peratures (Kohman
1934, Birdseye 1934# T re ssle r 1932). Enzymatic spoilage
occurred even a fte r what appeared to be adequate blanching
and d e stru ctio n of the enzymes (D iehl 1936).
It was determ ined th a t in those cases where the
tem perature of blanching was not excessively high, nor
th e tim e of blanching beyond a c e rta in d u ratio n , apparently
com pletely In activ ated enzymes were capable of reg eneratio n.
This phenomenon was by no means new. Woods (1902)
working w ith th e ju ices of tobacco was the f i r s t to note
i t . Aso (1903) found th a t enzymes of vegetables also were
capable of th is re a c tiv a tio n a fte r apparent d e stru ctio n by
h eat. Both these workers explained th is phenomenon not as
a reg en eratio n , but as the release of new enzymes from a
zymogen th a t was therm ostable.
