Table Of ContentTHE PENNSYLVANIA STATE COLLEGE
THE GRADUATE SCHOOL
DEPARTMENT OP DAIRY HUSBANDRY
•'ROMANO TYPE" GRATING CHEESE
A STUDY OF THE EFFECT OF SOME FACTORS ON THE RATE
OF FLAVOR AND BODY AMD TEXTURE DEVELOPMENT
A Thesis
by
JOSEPH FRANCIS MATTICK
Submitted in partial fulfillment
of the requirements
for the degree of
DOCTOR OF PHILOSOPHY
February 1950
Approved:
Head, Depsuytmenif of Dairy Husbandry
Professor of Dairy Manufacturing
ACKNOWLEDGEMENTS
The writer desires to express his appreciation and indebtedness
to the following:
Dr. C. D. Dahle, for suggesting the problem which was undertaken,
for his constant encouragement and many helpful suggestions through
construction criticisms throughout the experimental work and prepara
tion of this thesis.
Dr. D. V. Josephson and Professor A. A. Borland, for placing the
facilities of the department at the author’s disposal and making
this dissertation possible.
Professor F. J. Doan, for his ever willing advice, suggestions,
and discussions.
Dr. H. 0. Triebold, Dr. A. K. Anderson, and Dr. C. 0. Jensen,
Department of Agricultural and Biological Chemistry, and Dr. J. F.
Cone and Dr. J. C. Garey, Department of Bacteriology, for their
technical advice and suggestions.
The graduate students of the Dairy Department, for their inte-
r
rest, willing discussions of the problems that developed.
Kraft Foods, Inc., for the financial assistance given as a
research fellowship in the early part of the work.
TABLE OF CONTENTS
Page
INTRODUCTION 1
REVIEW OF LITERATURE 6
A. General Concepts of Catalysis 6
B. General Concepts on Mode of Action 7
C. General Characteristics of a Catalyzed Reaction 8
D. Classification of Biochemical Catalysts 8
E. The Chemical Nature of Enzymes 9
F. General Concepts of Enzyme Action 10
G. Factors Affecting Enzyme Action 11
1. The Effect of Substrates 12
2. The Effect of Temperature 13
3. The Effect of Hydrogen Ion Concentration 14
4. Effect of Activators on Enzyme Activity 15
5. Effect of Inhibitors on Enzyme Activity 16
6. Effect of Time on Enzyme Activity 17
H. Milk Lipase 18
1. Early Concepts of a Milk Lipase 19
2. Methods Used in Studying Milk Lipase 21
3. Factors Affecting Lipase Activity 23
a. Individuality and Stage of Lactation 23
b. Temperature 25
c. Shaking 29
d. Homogenization 30
e. Hydrogen Ion Concentration 34
f. Oxidation 35
g. Proteolysis 37
h. Other Factors 38
I. Pancreatic Lipase 38
J. Rohm and Haas Lipase Preparation 41
OBJECT OF EXPERIMENT 43
EXPERIMENTAL METHODS 45
Preparation 45
Ripening the Milk 46
Setting the Milk 46
Cutting the Curd 47
Cooking the Curd 47
Dipping the Curd 48
Page
Salting, Hooping, Pressing, and Dressing the Cheese 4.8
Source and Handling of Cultures 4.8
Sampling 4.9
Fat Determination 49
Total Solids Determination 51
pH Determination 51
Salt Determination 52
Volatile-Soluble and Volatile-Insoluble Fatty Acids 53
Ester Formation 54
Flavor Determinations 56
Body and Texture Determinations 56
DEFINITION OF TERMS 57
EXPERIMENTAL RESULTS 59
I. Natural Milk Lipase Study: Raw Skim— Raw Cream and One
Per Cent Streptococcus Lactis 59
Experiment I — 0 Per Cent Cream Homogenized 59
Experiment II - 25 Per Cent Cream Homogenized 61
Experiment III — 50 Per Cent Cream Homogenized 63
Experiment IV - 75 Per Cent Cream Homogenized 65
II. Natural Milk Lipase Study: Raw Skim— Raw Cream and 0.5
Per Cent Streptococcus Lactis and 0.5 Per Cent Lacto
bacillus Acidophilus 73
Experiment V - 0 Per Cent Cream Homogenized 73
Experiment VI - 25 Per Cent Cream Homogenized 74
Experiment VII - 50 Per Cent Cream Homogenized 76
Experiment VIII - 75 Per Cent Cream Homogenized 77
Experiment IX - 100 Per Cent Cream Homogenized 79
Experimental Results and Discussion
of Experiments I Through IX 87
Flavor in Milk and Whey 87
Membrane Formation 88
Flavors in Cheeses 89
III. Natural Milk Lipase Study: Pasteurized Cream— Raw Skim
and One Per Cent Streptococcus Lactis 97
Experiment X - 0 Per Cent Cream Homogenized 97
Experiment XI - 25 Per Cent Cream Homogenized 98
Experiment XII - 50 Per Cent Cream Homogenized 100
Experiment XIII - 75 Per Cent Cream Homogenized 102
Experiment XIV - 100 Per Cent Cream Homogenized 104
Page
IV. Natural Milk Lipase Study: Pasteurized Cream— Raw Skim
and 0.5 Per Cent Streptococcus Lactis and 0.5 Per Cent
Lactobacillus Acidophilus 112
Experiment XV - 0 Per Cent Cream Homogenized 112
Experiment XVI — 25 Per Cent Cream Homogenized 113
Experiment XVII - 50 Per Cent Cream Homogenized 115
Experiment XVIII - 75 Per Cent Cream Homogenized 117
Experiment XIX - 100 Per Cent Cream Homogenized 118
Experimental Results and Discussion of Experiments X
Through XIX 127
Flavors in Milk and Whey 127
Membrane Formation 128
Flavors in Cheeses 130
V. Rohm and Haas Lipase Study: Pasteurized Skim— Pasteurized
Cream and 1.0 Per Cent Streptococcus Lactis 135
Experiment XX - 0 Per Cent Cream Homogenized 135
Experiment XXI - 25 Per Cent Cream Homogenized 137
Experiment XXII - 50 Per Cent Cream Homogenized 139
Experiment XXIII — 75 Per Cent Cream Homogenized 142
Experiment XXIV — 100 Per Cent Cream Homogenized 144
VI. Rohm and Haas Lipase Study — Pasteurized Skim-— Pasteurized
Cream and 0.5 Per Cent Streptococcus Lactis and 0.5 Per
Cent Lactobacillus Acidophilus 153
Experiment XXV - 0 Per Cent Cream Homogenized 153
Experiment XXVI - 25 Per Cent Cream Homogenized 155
Experiment XXVII - 50 Per Cent Cream Homogenized 157
Experiment XXVIII— 75 Per Cent Cream Homogenized 159
Experiment XXIX - 100 Per Cent Cream Homogenized 161
Experimental Results and Discussion of Experiments XX
Through XXIX 170
Flavors in Milk and Whey 170
Membrane Formation 171
Flavors in Cheeses 172
Re-esterification 174
Homogenization 177
Culture Study 179
VII. Pancreatic Steap3in (Lipase) Study: Pasteurized Cream—
Pasteurized Skim and One Per Cent Streptococcus Lactis 180
Experiment XXX - 0 Per Cent Cream Homogenized 180
Experiment XXXI — 25 Per Cent Cream Homogenized 182
Page
Experiment XXXII - 50 Per Cent Cream Homogenized 184-
Experiment XXXIII — 75 Per Cent Cream Homogenized 186
Experiment XXXIV - 100 Per Cent Cream Homogenized 188
VIII. Pancreatic Steapsin (Lipase) Study: Pasteurized Cream—
Pasteurized Skim and Equal Amounts of Streptococcus Lactis
and Lactobacillus Acidophilus Culture 196
Experiment XXXV - 0 Per Cent Cream Homogenized 196
Experiment XXXVI - 25 Per Cent Cream Homogenized 19^
Experiment XXXVII - 50 Per Cent Cream Homogenized 199
Experiment XXXVIII - 75 Per Cent Cream Homogenized 201
Experiment XXXIX - 100 Per Cent Cream Homogenized 203
Experimental Results and Discussion of
Experiments XXX through XXXIX 211
Flavors in Milk and Whey 211
Membrane Formation 212
Flavors in the Cheeses 212
Homogenization 216
Culture Study 217
SUMMARY 218
CONCLUSIONS 225
BIBLIOGRAPHY 229
APPENDIX
INTRODUCTION
Prior to World War II, the bulk of the highly flavored condiment
type grating cheeses was imported from European countries. It is true
that several organizations in the United States were manufacturing
domestic products very similar to the imported varieties; however, their
production was relatively meager and could obviously be recognized
only for its supplementary value.
Shortly after the beginning of the war our reserve stocks of the
condiment types of cheeses gradually disappeared. This acute shortage
and the inability of our domestic industry to adequately meet the na
tional demands forced many food processing companies to use milder
flavored cheeses with inferior grating properties in their products,
or to import cheese from Argentina. This condition manifested itself
in the prepared spaghetti dinner components with their pasty, often
unclean, cheddar-like flavors.
Realizing the secrecy associated with processes and techniques used
by the foreign manufacturers — the art of "novelty-type” cheesemaking
being handed down orally with a family for centuries — and the close
relationship of our domestic-foreign type of grating cheese industry to
Italian and family ancestry, it was apparent that application of experi
mental evidences would have to be applied to the cheese making process.
Attempts at estimating the future status of the foreign cheese
market in our country, with evaluations of past records, resulted in
2
many possible problems. If conditions would revert to the pre-war import
magnitude, it would be commercially impossible for the domestic industry
to compete for that market, without the aid of high protective tariffs
because of the marked differences in costs of production, assuming that
identical methods of manufacturing were used. Considering our foreign
policy with its desire to stabilize foreign economies, it is difficult
to realize high protective barriers placed on foreign trade, especially
if the products are important sources of revenue for the country or
conntries involved.
It must also be remembered that the imported cheese products that
have reached and will reach our markets have been and will be only the
superior grades (from a body and flavor standpoint) which means that
we must, of necessity, produce a product consistently comparable to the
best that the foreign countries offer.
It hasn’t been too many years ago when the old concept prevailed,
especially with our naturalized citizens, that foreign products must be
made in the country that originally developed them since with our domes
tication the individuality of the product was lost. Actually, these
products were some of the material linkages that joined their acquired
American present with their actual or educated foreign past. The notion
that a tradesman’s product and its degree of fineness or perfection was
a material personification of himself or his nationality was and is a
common impression among our foreign born. These concepts in the past
have been the major factors in our meager domestic production since our
duplication products were considered inferior by the most important con
sumers of the products.
3
The past decade with its war years and various rationings resulted
in many changes in food planning. Cheeses, in one form or another,
during those years made up a major portion of the meat substitutes be
cause of their nutritional value as well as their relatively low cost
and adequate availability. One of the most important outgrowths of the
food rationing period was the acceptance of the various highly flavored
cheeses as condiments. This means that the consumption of these products
is no longer, directly or indirectly, controlled by or restricted to
the nationalities who have in the past ignored our domestic products
in preference to the imported varieties. Italian-type grating cheeses
are now just as Americanized as salt or pepper and have rightfully as
sumed their accepted position as a seasoning in the American household
and food processing organizations.
According to Dr. L. S. Palmer's (14-8) chemical definition, "Milk
is a microscopic dispersion of fat in an aqueous plasma, containing
molecularly dispersed lactose and certain mineral salts, and colloidally
dispersed proteins, of which calcium caseinate and lactalburain predo
minate, as well as colloidally dispersed calcium phosphate (Ca2H2(P0^)2),f.
The various cured and uncured cheeses are the products of degradation
or conversion of most of the components of the above mentioned system
with such methods and to such degrees that the resultant cheeses main
tain the characteristics of their respective types. Each manufacturing
process is related to every other process ih many ways and to various
degrees; however, each product has its individual characteristics which
makes it different from all others.
!
A cheese, regardless of type, is composed of many interdependent,
complex systems and fundamentally any evaluation of the chemical,
physical, or physico-chemical changes that occur in the cheese manu
facturing and curing process should engulf the systems as a unit through
the study of the effects of the interreaction between systems on all
components of the unit. It is our lack of information and techniques
that makes such an ideal evaluation impossible at the present time.
The concept that a "Romano-type'1 grating cheese can be produced
with a short curing period through applications of an experimental
process that forces or catalyzes the progress of reactions toward the
desirable quality characteristics of the long curing foreign products,
has been demonstrated at this institution. Several experiments were
made by Dahle, et al. (20) during the past decade in an effort to
make a quick curing grating type cheese with encouraging results.
The usual curing period for imported and domestic Romano cheese is
10 months to two years. The minimum ripening period required by our
legal standards is six months. Since the cost of raw products, manu
facturing, equipment, and labor cannot be reduced, the reduction in
processing costs must, therefore, occur during the curing process. The
curing period of cheese represents a major portion of the costs of
manufacturing. Any reduction in the curing time accordingly reduces
the manufacturing cost of each unit. The length of the curing period
is, therefore, of utmost importance economically to the manufacturer
since invested capital could reach appreciable amounts with an exces-
