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Author: Patel, Pranaykumar V.

Title: Effect of Potassium Chloride and Potassium-Based Emulsifying Salts as a Salt

(Sodium chloride) Replacer on the Chemical and Microbiological Characteristics

of Pasteurized Process Cheese

The accompanying research report is submitted to the University of Wisconsin-Stout, Graduate School in partial completion of the requirements for the Graduate Degree/ Major: MS Food & Nutritional Sciences Research Adviser: Eun Joo Lee, PhD Submission Term/Year: Spring, 2012 Number of Pages: 47 Style Manual Used: American Psychological Association, 6th edition

I understand that this research report must be officially approved by the Graduate School and that an electronic copy of the approved version will be made available through the University Library website

I attest that the research report is my original work (that any copyrightable materials have been used with the permission of the original authors), and as such, it is automatically protected by the laws, rules, and regulations of the U.S. Copyright Office.

My research adviser has approved the content and quality of this paper.

STUDENT: NAME Pranaykumar Patel DATE: 05/16/2012 ADVISER: (Committee Chair if MS Plan A or EdS Thesis or Field Project/Problem): NAME Eun Joo Lee, PhD DATE: 05/16/2012 ----------------------------------------------------------------------------------------------------------------------------- ---- This section for MS Plan A Thesis or EdS Thesis/Field Project papers only Committee members (other than your adviser who is listed in the section above) 1. CMTE MEMBER’S NAME: DATE: 2. CMTE MEMBER’S NAME: DATE: 3. CMTE MEMBER’S NAME: DATE: ----------------------------------------------------------------------------------------------------------------------------- ---- This section to be completed by the Graduate School This final research report has been approved by the Graduate School. Director, Office of Graduate Studies: DATE:

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Patel, Pranaykumar V. Effect of Potassium Chloride and Potassium-Based Emulsifying Salts

as a Salt (Sodium chloride) Replacer on the Chemical and Microbiological Characteristics of

Pasteurized Process Cheese

Abstract

The consumption of sodium in excessive amount may lead to heart disease, which is the

first leading cause of death in the United States. Process cheese is one of the high salt containing

milk products. The objective of this study was to evaluate and compare the effects of potassium

chloride (KCl) and potassium based emulsifying salts as a salt (NaCl) replacer on the chemical

and microbiological characteristics of pasteurized process cheese. The Treatment 1 and Treatment

2 samples of process cheese were made using the potassium chloride (KCl) and a mixture of 50 %

of potassium chloride and 50 % of sodium chloride (NaCl+KCl). The control sample of processed

cheese was made using the sodium chloride (NaCl) only. The process cheese samples were

analyzed for chemical and microbiological characteristics such as fat, moisture, pH, salt,

meltability, protein, total plate counts, coliform counts, and yeast and mold counts. The results of

fat content, moisture content, pH and meltability of process cheese samples were not statistically

significant different, but the sample of process cheese made using the potassium chloride (KCl)

had higher protein content than the control and Treatment 2. In the results of microbiological

analysis, control had the lowest number of microbial counts followed by Treatment 2 (NaCl+KCl)

and Treatment 1 (KCl). In conclusion, potassium chloride had high possibility to use as a salt

replacer without changing the chemical properties, but it has limited ability to produce process

cheese with same shelf life as sodium chloride.

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Acknowledgements I would like to thank to the many people who supported and helped me in the completion of

my research experiment and thesis writing. First of all I would like to record my gratitude to Dr. Eun

Joo Lee, my research advisor, for her supervision, advice and guidance from the very beginning of the

research as well as throughout the work. Her support for the thesis editing in limitless time made it

possible to complete my research and thesis work. I would like to thank Dr. Carol Seaborn, for her

advice and guidance from the very first day of my graduate study until the completion of my research

work and thesis. I would like to thank Dr. Carolyn Barnhart for her help and support during my

graduate school class work as well as during my research work. I wish to express my sincere gratitude

to Connie Galep and her assistants, who helped me in finding laboratory materials. I am also thankful

to Ron Mc Kernan and Terry “Doc” Holliday of Whitehall Specialties for providing their facilities to

make the processed cheese. Last but not the least, I would like to thank my family members for

their support and help me during my entire graduate study at UW-Stout by financing, advice and love.

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Table of Contents ………………………………………………………………………………………………. Page Abstract ........................................................................................................................................ 2 List of Tables ................................................................................................................................ 7 List of Figures ............................................................................................................................... 8 Chapter I: Introduction ................................................................................................................ 9 Chapter II: Literature Review ...................................................................................................... 14

Introduction .................................................................................................................... 14

Background of Process Cheese ....................................................................................... 15

Process Cheese and Salt Content ..................................................................................... 16

Factors Affecting the Functional Properties of Process Cheese ..................................... 17

Natural cheese ..................................................................................................... 18

Emulsifying salts ................................................................................................. 19

Formulation and processing ................................................................................ 20

Effect of Salt Reduction on Functional Properties of Process Cheese ........................... 21

Effect on chemical Properties .............................................................................. 21

Effect on microbiological properties .................................................................. .22

Effect on textural properties ................................................................................ 22 Effect on sensory properties ................................................................................ 23

Chapter III: Methodology ........................................................................................................... 24

Process Cheese Manufacture .......................................................................................... 24

Formulation of raw materials .............................................................................. 24 Manufacture of process cheese ............................................................................ 26

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Chemical Analysis of Process Cheese ............................................................................. 27

Moisture content of process cheese .................................................................... 27

Fat content of process cheese .............................................................................. 27

Protein content of process cheese ....................................................................... .27 Salt content of process cheese ............................................................................ .28 pH of process cheese .......................................................................................... .28 Meltability of process cheese ............................................................................. .28

Microbiological Analysis of Process Cheese ................................................................. .29

Total plate counts (TPC) ................................................................................... .29 Coliform counts .................................................................................................. .29 Yeast and mold counts ....................................................................................... .29

Statistical Analysis ......................................................................................................... .30

Chapter IV: Results and Discussion .......................................................................................... .31

Effect on Chemical Characteristics ................................................................................. 31

Moisture ............................................................................................................... 31 Fat ........................................................................................................................ 32 Protein ................................................................................................................. 32 Salt ....................................................................................................................... 33 pH ........................................................................................................................ 34 Meltability ........................................................................................................... 35

Effect on Microbiological Characteristics ..................................................................... 35 Total plate counts (TPC) .................................................................................... 36 Coliform counts ................................................................................................... 37

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Yeast and mold counts ........................................................................................ 37 Chapter V: Conclusions .............................................................................................................. 39 Recommendations for Further Study ............................................................................ 39 References ................................................................................................................................... 40

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List of Tables

Table 1: Formulation of Process Cheese Samples Using Different Salts ................................... 25 Table 2: Effect of Types of Salts on Chemical Characteristics of Process Cheese ..................... 31 Table 3: Effect of Types of Salts on Microbiological Characteristics of Process Cheese .......... 35

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List of Figures

Figure 1: Effect of types of salt on % salt content of process cheese ......................................... 34

Figure 2: Effect of types of salt on total plate counts (TPC), coliform counts, yeast and

mold counts of process cheese ..................................................................................... 36

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Chapter I: Introduction

The Centers for Disease Control and Prevention (CDC) reported that heart disease and

stroke are the first and the fourth leading causes of death in the United States resulting from high

blood pressure (Murphy et al., 2012; Ostchega et al, 2008). Among all adults in the United

States, approximately 29% had hypertension (high blood pressure) and around 28% had pre-

hypertension in 2005-2006 (Ostchega et al, 2008). Hypertension is the condition caused by high

blood pressure, which results from high salt intake. Dickinson and Havas (2007) suggest there is

no doubt that reducing hypertension by controlling blood pressure keeps the human body

healthy. Results for sodium intake and its effects on human blood pressure were derived from

scientific research, animal studies and other human surveys (Doyle, 2008; Kesteloot & Joossens,

1988; Cutler et al., 1997; Meneton et al., 2005). The Intersalt group did the study regarding salt

intake and its effect on blood pressure on 10,000 men and women at 52 different locations in 32

nations (Elliott, 1988). The data from this study demonstrate that people with low sodium

intakes have a moderate blood pressure, and it was not increased during any period of life. The

other finding of this study was that location and country also affected sodium intake and blood

pressure. According to the Intersalt group study, there was negative relationship between

potassium intake and blood pressure.

Consumption of sodium in excessive amounts may cause the problem and lead to other

health-related issues. Cardiovascular disease (CVD) is another disease resulting from high

dietary salt intake. High blood pressure is one of the factors causing the CVD, which results

from high sodium intake in diet. The mechanism of effect of salt on blood pressure could be due

to the rise in plasma sodium or to the increase in extracellular fluid volume (De Wardener et al,

2004). Still, the proper way in which salt intake affects the heart and blood pressure was not

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fully understood by researchers (De Wardener et al., 2004; Doyle, 2008). Even with good

exercise in daily life, there is a chance that an individual may develop CVD with high intake of

dietary sodium (Doyle, 2008). Higher dietary sodium intake is also related to bone disease

(Doyle, 2008). Calcium and sodium metabolism are interconnected in the human body. As

sodium consumption in the diet increases, absorption of calcium ions decreases.

Salt is one of the required dietary elements for the body to maintain its normal

physiochemical and physiological activity. Salt controls these activities by maintaining bodily

fluids. Sodium, in association with other ions like potassium, chloride and other ions, controls

the blood and osmotic pressure of the body and maintains the level and volume of extracellular

fluids in the body (Gibson et al., 2000). Kidneys are the most important organ in body; they

control the level and amount of sodium in the human body by passing it to the urinary track. Salt

is menially composed of two elements: sodium and chloride. There are varieties of salt available

in market for use depending upon the origin, size of salt grain and extent of refining process.

According to Dietary Guidelines for Americans (2010), recommended daily intake of sodium for

an adult is 2300 mg per day (USDA, 2010). The average estimated intake of sodium for all

American age groups is approximately 3400 mg per day, which is higher than the recommended

daily allowances. This guideline also recommended a daily intake of 1500 mg sodium for an

individual who is suffering from chronic diseases or who is older than 51. In addition, dietary

guidelines provide the recommendation to consume less than 300 mg of dietary cholesterol per

day. The human body can absorb different levels of sodium, and 98% of that sodium goes to an

intestine (Doyle, 2008). The first and foremost concern for the researcher working on salt and its

effect on human health is the relationship between salt intake and its effect on chronic diseases

(Gibson et al, 2000).

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The consumption of processed foods including meat products, dairy products and

beverages increases day by day in the United States. Processed food contains a higher amount of

salt or sodium content. This salt or sodium is one of the major factors affecting the human

health. Salt intake is related to human blood pressure affecting heart activity. Process cheese,

process cheese food and process cheese spread are the main sources of the salt in human diet.

Process cheese is frequently consumed cheese in United States people’s diet.

The United States (US) is one of the biggest nations in the world accounting for the

production of cheese. United States total cheese production comprises 30% of total world cheese

production. Processed cheese is one of the most popular types of cheese in the US and

worldwide with its remarkable development in lengthening manufacturing capacity (Award et

al., 2004). Process cheese was first commercially manufactured in Switzerland by Walter Gerber

and Fritz Stettler in 1911. The purpose behind making process cheese in Switzerland was to

extend the shelf life of cheese for export to the warmer climate countries. In the United States,

process cheese was first commercially made by James L. Kraft in 1916. James Kraft was the

first man who made process cheese commercially under the brand name, Kraft process cheese.

In the United States, according to the Code of Federal Regulation (21 CFR 133.169 to 133.180),

process cheese is categorized into three different groups depending upon the formulation and

ingredients used (CFR, 2006). The three groups of process cheese include Pasteurized Processed

Cheese (PC), Pasteurized Processed Cheese Food (PCF), and Pasteurized Processed Cheese

Spread (PCS). The three different groups of process cheese differ in their fat and moisture

content, too. According to the standard of identity, process cheese should meet the requirement

of a minimum 47% (DMB) and maximum 43% moisture (CFR, 2006). The optional ingredients

for Pasteurized process cheese (PC) manufacture can be either cream or anhydrous milk fat

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(AMF). In the same way, Pasteurized process cheese food (PCF) also has a standard of identity

and needs to meet the requirements of a minimum of 46% fat and a maximum of 44% moisture

(CFR, 2006). Pasteurized process cheese food (PCF) manufacture can be done by using skim

milk, buttermilk or cheese whey as an optional ingredient (CFR, 2006). Pasteurized process

cheese spread (PCS) would meet the requirement of minimum 40% fat and maximum moisture

60% but not lower than the 44% (CFR, 2006). The optional ingredients used for Pasteurized

process cheese spread (PCS) manufacture include the stabilizers, sweetening agents in addition

to the ingredient used for PC and PCF (CFR, 2006). According to the code of federal regulation

(21 CFR 133.169 to 133.180), Process cheese can be labeled depending upon the cheese used for

making the process cheese and amount of salt used (CFR, 2008b). According to National

Agricultural Statistics Service, total cheese production in the year 2010 was 10.4 billion pounds,

among that production of process cheese was 4.2 billion pounds (USDA, 2011). Process cheese

production in the US comprised 20% of total cheese production in 2010 (USDA, 2011).

Processed cheese is manufactured by mixing single or varieties of natural cheese of the same or

different ageing periods with a coloring agent, emulsifying salt and water with heat treatment to

get the uniform mixture (Award et al, 2004). Process cheese is an oil-in-water type of emulsion.

Process cheese can be packed into different forms, which include blocks, slices, or sticks

depending upon the ultimate use (Tamime et al., 2011). Sodium Chloride (NaCL) has been used

as a preservative and flavor enhancer to make processed cheese for many years (Ayyash & Shah,

2010). Milk and milk products account for approximately 11% of total sodium intake in the diet

of people of United States (Ayyash & Shah, 2010).

Recently the whole world, including the United States, has concentrated on strategies to

reduce salt content in the human diet. This issue regarding salt reduction in human diet has

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become popular. Studies related to salt reduction demonstrated that, in vivo and in vitro salt

replacers can reduce the risk of developing cardiovascular diseases because it can control the

blood pressure of human body. Reduction of salt content in processed foods, including process

cheese, has a great opportunity to reduce sodium intake in the human diet by changing the type

of salt.

This research project is aimed at reducing the salt in process cheese by changing the type

of salt used to manufacture process cheese. By changing the type of salt used, the amount of

sodium in the human diet can be controlled. The objectives of this research project are 1) to

develop a healthy, reduced salt process cheese and 2) to characterize and quantify the chemical

and microbiological properties of process cheese with the salt (sodium chloride, NaCl) replacer

(potassium chloride, KCl).

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Chapter II: Review of Literature

Introduction

The reduction of dietary sodium intake is a necessary step for the control of blood

pressure and heart diseases in human body. Elliott (1988) reported that a change in blood

pressure level depends upon the sodium intake in the human diet. The reduction of salt intake in

the human diet could be achieved through the combined efforts of manufacturers and consumers.

Henney et al. (2010) recommended that the Food and Drug Administration (FDA) set a

maximum allowed limit for salt addition in processed food. New York City Department of

Health and Mental Hygiene (2010) set the goal of 25% reduction in salt intake in human diet

through the voluntary program over the period of five years. In the United Kingdom (UK), the

Food Standard Agency (2006) set the goal for not more than 6g per day of sodium consumption.

World Action on Salt and Health is a group that worked with government and industry in 80

countries around the world to reduce dietary sodium intake (WASH, 2005).

Process cheese (PC) is an important part of the diet of the American people. The main

factor contributing to the limited consumption of process cheese was its salt content. There were

three main sources from which the salt content of process cheese contributed to limited

consumption, including the type of natural cheese used, sodium chloride and emulsifying salts.

Process cheese is the dairy product that is manufactured by the mixing dairy and non-dairy

ingredients, which include single or different varies of cheese, sodium chloride and emulsifying

salts. This mixture of dairy and non-dairy ingredients was followed by the heating process to

produce a homogenous pasteurized product with a longer storage period (Kapoor & Metzger,

2008). The physiochemical characteristics of process cheese can be attributed to the

microstructure of process cheese (Kapoor & Metzger, 2008). The gelling and emulsification

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properties of casein in natural cheese are modified by the addition of emulsifying salts. Common

salts used in the manufacture of process cheese include the sodium salts of citrate and phosphate.

The main purpose of the addition of emulsifying salt is to disturb the protein network, which

links the calcium-phosphate of natural cheese (Gupta et al., 1984). An emulsifying salt addition

to natural cheese results in changes to the calcium-phosphate linkage protein network in natural

cheese and makes the hydrophobic and hydrophilic part of the casein more available for the

reaction. These changes to the casein became more favorable for the production of the

homogeneous mass when heat is applied. The pasteurization of process cheese makes the

hydrophilic and hydrophobic groups of the casein favorable to interact with the water and fat

phases of the mass (Marchesseau et al, 1997; Lee et al., 2003). This process results in the

formation of process cheese with uniform body and texture.

Background of Process Cheese

The history of process cheese is a few decades old. The manufacturing of process cheese was

noted for the first time in Europe in the mid-1890s. The shelf life of natural cheeses was limited

depending upon factors such as raw ingredients used for manufacture, processing methods and

storage parameters of the products. The manufacture of process cheese became necessary for

extending the storage period of natural cheese with a new variety of cheese which was a little bit

less strong in flavor. During the same period of time, research and development in Germany to

extend the shelf life of the soft type cheese (Limburger, Camembert and Brie) for the purpose of

export was accomplished by the pasteurized of cheese in the can. In Switzerland, there were also

developments in the shelf life extension of Dutch type cheese by using sodium citrate, but these

developments did not succeed. Process cheese was commercially produced in Europe and the

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US between 1910 and 1920. Initially, the shelf life of process cheese was not long but during the

1930s this process for manufacturing process cheese became very popular because of the

availability of emulsifying salts in the market. Many authors reviewed the technological

development aspects of process cheese (Marchesseau et al., 1997; Schar & Bosset, 2002;

Dimitreli & Thomareis, 2007; Kapoor & Metzger, 2008). The Food and Drug Administration

(2006) defines process cheese as follows:

Process cheese is the food manufactured by… the mixing of same or two or more

varieties of cheese… with an emulsifying agent… with the aid of heat… to produce

uniform homogeneous plastic mass…it may contain optional ingredients including an

acidifying agent…, anhydrous milk fat…, Cream…,water, salt, harmless artificial

coloring…,Process cheese was heated at a temperature not less than 150F for not less

than30 sec….it also contains minimum 30% of milk fat… and maximum 40% of

moisture. (p. 340)

Process Cheese and Salt Content

Salt has played an important role in the human body and in the food manufacturing

industry (Gibson et al., 2000). Excessive use of salt in the diet creates the health problems for

the human body. Consumption of processed foods leads to higher levels of sodium in the human

body. The main function of salt in the body is to maintain bodily fluids within limits (Gibson et

al., 2000). Excessive amounts of sodium are directly related to high blood pressure. An

individual with high blood pressure could have the risk of kidney disease, cardiovascular disease,

and congestive heart failure. Most Americans, from the age of 2 years and older consume more

than enough sodium in their diets. The average intake of sodium for Americans 2 years and

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older is 3400 mg per day, while the recommended daily intake of sodium is 2300 mg per day.

Sodium is consumed by the human body in the form of salt. Salt has been used for different

purposes in different food process applications. Salt can be added to reduce moisture, to cure

meat, and to enhance flavor and to mask unwanted flavor. Very little of total salt intake can be

attributed to salt added at the table. The main source of sodium intake in the human body is

processed food, including process cheese. The total sodium intake in the human body is not only

due to the consumption of food with high sodium content, but also to the frequent consumption

of food with lower sodium content, which results in total high sodium intake. The major source

of sodium in the human body is processed and restaurant foods, which accounts for almost three

parts (77%) of total sodium consumption. There is a small amount of salt naturally present in

food, which makes only a 12% contribution to the total salt consumption in the human diet.

Some people like to add salt at the table, which contributes 6% of the total. Five percent of total

salt comes from the addition during cooking (Mattes & Donnelly, 1991). Process cheese is one

of the highest salt-containing dairy products amo12ng all dairy products. The range for sodium

content of process cheese is 325 to 798 mg/50gm of process cheese (CFR 21, 2008d). The main

ingredients that contribute to the total sodium in process cheese include natural cheese

(approximately 28% to 37%), added emulsifying salts (ranging from 44% to 48%), and added

salt (ranging from 15% to 24%). One of these three ingredients can be modified for the

development of low and/or reduced sodium process cheese.

Factors Affecting the Functional Properties of Process Cheese

Process cheese is a combination of fat, protein, salt and water in a complex system. The

functional property of cheese could be influenced by the maturity of raw cheese used, types of

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emulsifying salts and the processing method used for manufacturing it (Kapoor & Metzger,

2008). The final quality of process cheese depends on the amount of raw ingredients used and

the type of processing method applied. The functional properties of process cheese are not only

influenced by compositional changes, but also by processing conditions that also contribute to

the factors controlling the characteristics of process cheese (Kapoor & Metzger, 2008).

Natural cheese. Natural cheese is one of the main ingredients used for the

manufacturing of process cheese. According to the FDA (2006), natural cheese added in the

manufacturing of process cheese varied from 51 to >80% depending upon the type of process

cheese manufactured. Functional properties of process cheese, such as meltability and melted

texture, were influenced by the characteristics of natural cheese used (Kapoor & Metzger, 2008).

For a long time, researchers had tried to investigate the influence of natural cheese characteristics

on process cheese quality (Kapoor & Metzger, 2008). Functional properties of process cheese

could be affected by the natural cheese made from concentrated milk (Acharya & Mistry, 2005).

Some of the physiochemical properties of natural cheese influenced the final quality of process

cheese, including Ca content, pH and the age of the natural cheese (Templeton & Sommer, 1930;

Vakaleris et al., 1962; Olson et al., 1958). Olson et al. (1958) demonstrated the effect of pH on

natural cheese qualities of process cheese. The Ca present in natural cheese could affect the

functionality of process cheese. The amount and form of Ca present in natural cheese had an

effect on process cheese, but there was not enough research to document the effect (Olson et al.,

1958). The age of the natural cheese had an influence on the characteristics of process cheese.

Natural cheese demonstrated an inverse relation to its age and intact casein content (Garimella

Purna et al., 2006). As the age of natural cheese increased, the intact casein content decreased.

This happened because of the enzyme and starter culture present in the natural cheese breakdown

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the protein into peptide. Aging of natural cheese had great influence on process cheese

functionality, and this was supported by the research done on the effect of natural cheese age on

process cheese functionality (Templeton & Sommer, 1930; Arnott et al., 1957; Olson et al.,

1958; Vakaleris et al., 1962; Piska & Stetina, 2003; Garimella Purna et al., 2006). As the age of

natural cheese used for manufacturing of process cheese increased, the meltability of process

cheese increased (Olson et al., 1958; Vakaleris et al., 1962; Garimella Purna et al., 2006), and

unmelted firmness decreased (Templeton & Sommer, 1930; Olson et al., 1958; Vakaleris et al.,

1962; Piska & Stetina, 2003; Garimella Purna et al., 2006).

Emulsifying salts. Emulsifying salts were one of the most important factors controlling

the functionality of process cheese. There were three main different groups of emulsifying salts,

including monophosphates, polyphosphates and citrates (Kappor & Metzger, 2008). According

to the FDA, the emulsifying salts which could be used for the manufacture of process cheese

include one or any mixture of two or more of the following salts: monosodium phosphate,

disodium phosphate, dipotassium phosphate, trisodium phosphate, sodium metaphosphate

(sodium hexametaphosphate), sodium acid pyrophosphate, tetrasodium pyrophosphate, sodium

aluminum phosphate, sodium citrate, potassium citrate, calcium citrate, sodium tartrate, and

sodium potassium tartrate (CFR 21 133.169). Emulsifying salts were not emulsifier because

they were not amphiphilic in nature (Dalgleish, 2006). When emulsifying salts were used in

combination with the aid of heat and shear, they changed the cheese protein capacity for

emulsification. The effect of emulsifying salts on the quality of process cheese was detailed by

the researchers in the literature (Guinee et al., 2004). The use of a particular emulsifying salt in

excessive amounts leads to a change in the quality of process cheese (Mayer, 2001). Dalgleish

(2006) demonstrated the main purpose of using emulsifying salt for the manufacture of process

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cheese as follows: 1) to break the micelle and to free the calcium from the micelle, 2) to make

the protein soluble, 3) to stabilize the emulsion by fat emulsification, 4) to adjust and control the

pH and 5) to produce homogeneous plastic mass upon cooling.

Some of the results from this research related to the use of emulsifying salts that had an

adverse effect on process cheese quality were conflicting. Use of sodium hexametaphosphate for

process cheese manufacture leads high levels of fat emulsification and excessive amounts of

soluble calcium (Mizuno & Lucey 2005). Citrates were the least able to bind calcium and

initiate protein peptization, while another researcher highlighted that trisodium citrates had the

greatest ability to bind calcium and to peptize protein (Mizuno & Lucey 2005).

Formulation and processing. The formulation and processing method for the

manufacture of process cheese also affected the final quality of process cheese (Garimella et al.,

2006). The final desired characteristics of process cheese were an important parameter for its

use in different applications, and these final desired characteristics can be affected by the

ingredients used and the processing method used for manufacture (Garimella et al., 2006).

Formulation includes the type and amount of ingredients used while processing, consisting of

temperature and temperature of cooking. The speed of mixing and the rate of cooling were also

a part of the processing parameters which could affect the process cheese quality. The type and

amount of natural cheese used to have influence on process cheese characteristics (Kapoor &

Metzger, 2007). An age of the natural cheese was contributed for the factors controlling the

process cheese quality. The other ingredients used were emulsifying salts which had also

effected on process cheese. The type and level of emulsifying salts used for manufacture of

process cheese also control the final desired characteristics of process cheese (Kapoor &

Metzger, 2008). An additional parameter which controls the process cheese functionality

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includes the temperature and rate of mixing used for manufacture of process cheese. The

researcher had been detailed the importance of effect of cooking temperature and mixing rate on

uniformity of fat distribution in process cheese (Glenn et al., 2003; Lee et al., 2003). The length

of cooking of process cheese had straight relation with firmness of process cheese (Swenson et

al., 2000). Templeton and Sommer (1930) reported as the cooking temperature of process

cheese increased the firmness of process cheese also increased. Processing parameter and

formulation could change the process cheese functionality depending upon the extent to which

they were used.

Effect of Salt Reduction on Functional Properties of Process Cheese

Salt reduction in the food industry was one of the challenging tasks and opposed by food

processors and salt manufacturers (Gibson et al., 1998). Salt reduction in process foods directly

affects the functional property of foods, including the flavor. Salt reduction can be achieved

either by changing personal perceptions of salty taste or changing food formulations (Gibson et

al., 2000). Another way to reduce the salt content in processed foods is a gradual reduction in

salt content (Gibson et al., 2000).

Effect on chemical properties. Reducing the salt in process cheese definitely affects the

chemical properties of process cheese. Chemical properties of process cheese include pH,

moisture content, fat content, protein content, insoluble calcium content and insoluble phosphate

content. Reducing the salt content in process cheese can affect the pH and moisture content

(Shirashoji et al., 2006). Insoluble calcium and phosphate were also affected by salt reduction in

process cheese (Shirashoji et al., 2006). All of these chemical parameters, either directly or

indirectly, affect the functional properties of process cheese (Shirashoji et al., 2006). Protein

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content of process cheese is one of the chemical attributes that may differ in quantity due to the

reduction of salt in process cheese (Mizuno & Lucey, 2005). Sodium content of process cheese

depended upon the type of emulsifying salts used and if any salt replacer was used.

Effect on microbiological properties. Salt is one of the oldest and most effective

preservatives for process cheese (Taormina, 2010). Salt reduction in process cheese was related

to a change in microbiological safety and shelf life. Salt was one of the hurdles in the

preservation of process cheese (Taormina, 2010). Recent developments in food formulation,

processing, packaging and engineering would be an alternate for maintaining the shelf life of

process cheese with salt reduction. However, some of the pathogenic organisms could survive

refrigeration conditions and might create a threat to human health (Nolan et al., 1992; Sofos,

1983) suggested that the reduction of the salt in process cheese was based on the result of

appropriated research and data regarding the salt reduction. Reddy and Marth (1991) reviewed

the effect of salt reduction in process cheese and its effect on the stability of pathogenic

organisms that cause food poisoning.

Effect on textural properties. An emulsifying salt when used for the process cheese

manufacture either in single or in blends affects the textural property (Gupta et al., 1984).

Shirashoji et al., (2006) highlighted the effect of reducing the emulsifying salt content on the

functional property of process cheese. Reducing the emulsifying salt for process cheese

manufacture leads to an increase in processing time and ultimately affects the texture. Textural

properties of process cheese include hardness, chewiness, fracturability, cohesiveness, and

adhesiveness (Mizuno & Lucey, 2005). The hardness of process cheese was greatly influenced

by the change in the type and amount of emulsifying salts used for manufacture. Cohesiveness,

adhesiveness and chewiness were also different for process cheese depending upon the

23

emulsifying salts used in the manufacturing process (Mizuno & Lucey, 2005). An emulsifying

salt also controlled the meltability and stretchability of process cheese. The microstructure of

process cheese was changed by changing the type and amount of emulsifying salt used for the

manufacture of process cheese.

Effect on sensory properties. Salt is one of the cheap and best flavoring substances for

food, including process cheese. Salt can also provide other benefits to process cheese, including

flavor enhancement and preservative effects (Liem et al., 2011). When the salt content of

process cheese was reduced by changing the emulsifying salts or reducing the amount of

emulsifying salts, consumer acceptability of a product was affected. Researchers highlighted the

effect of immediate salt reduction, noting an incremental reduction in the consumer acceptability

of process cheese (Liem et al., 2011).

24

Chapter III: Methodology

Material and methods used for manufacture and analyses of process cheese samples are

described in this chapter. Analysis of process cheese includes the chemical and microbiological

characteristics. Chemical analysis of process cheese includes fat, moisture, pH, protein, salt and

sodium content determination while microbiological characteristics include the total plate count,

yeast and mold count and coliform count.

Process Cheese Manufacture

The manufacture of process cheese was a step-by-step process that included the

formulation of raw ingredients and manufacture process cheese. Three types of process cheese

were made using different formulations and different emulsifying salts.

Formulation of raw ingredients. Three different types of process cheese samples were

made using different formulations for the salt and different emulsifying salts. The salts used for

different process cheese samples included sodium chloride, potassium chloride and a mixture of

sodium and potassium chloride. The emulsifying salts used for process cheese samples included

sodium citrates, potassium citrates and dipotassium phosphates. The amount of each ingredient

used for the manufacture of process cheese was calculated using an Excel-based program. The

Excel-based program used for process cheese formulation was Techwizard. Techwizard was

developed by a company named OWL Software, situated in Lancaster, Pennsylvania. The

formulation included different types of salts and emulsifying salts used at the same level for

different process cheese sample manufacture. The level of each ingredient used for the

manufacture of individual process cheese samples is detailed in the following table:

25

Table 1

Formulation for Process Cheese Samples Using Different Salts (unit: g)

Ingredients Control Treatment 1 Treatment 2

Cheddar cheese 4425.0 (88.50 %) 4425.0 (88.50 %) 4425.0 (88.50 %)

Anhydros milk fat 141.5 (2.83 %) 141.5 (2.83 %) 141.5 (2.83 %)

Sodium citrates 140.0 (2.80 %) 0.0 (0.00 %) 70 (1.40 %)

Potassium citrates 0.0 (0.00 %) 70 (1.40 %) 0.0 (0.00 %)

Dipotassium phosphate 0.0 (0.00 %) 70 (1.40 %) 70 (1.40 %)

Sodium chloride 25.0 (0.50%) 0.0 (0.00 %) 12.5 (0.25 %)

Potassium chloride 0.0 (0.00 %) 25.0 (0.50 %) 12.5 (0.25 %)

Sorbic acid 10.0 (0.20 %) 10.0 (0.20 %) 10.0 (0.20 %)

Lactic acid 7.5 (0.15 %) 7.5 (0.15 %) 7.5 (0.15 %)

Carotenal 0.8 (0.02 %) 0.8 (0.02 %) 0.8 (0.02 %)

* Formulation based on making10 lb process cheese

For the Control sample of process cheese, the salt and emulsifying salts used were

sodium-based only. For Treatment 1, the sample process cheese was manufactured using

potassium-based salt and emulsifying salts. Treatment 3 process cheese samples were

manufactured using potassium- and sodium-based salts and emulsifying salts in a 50-50%

mixture. The remaining ingredients used for the manufacture of all three different types of

process cheese remained the same. The amounts and types of Cheddar cheese, anhydrous milk

fat, preservative, acid used for pH adjustment, and color were the same for all three process

cheese samples. The formulation gave % weight and amount needed to manufacture each of the

three process cheese samples in 10 lb quantities.

26

Manufacture of process cheese. Three process cheese samples were made using

different formulations. The Control process cheese sample contained only sodium chloride and

sodium citrate as an emulsifying salt. The Treatment 1 process cheese sample was manufactured

using potassium chloride as a salt and a mixture of potassium citrate and dipotassium phosphate

as an emulsifying salt. The Treatment 2 sample was made using sodium and potassium chloride

as a salt and a mixture of sodium citrate and dipotassium phosphate as an emulsifying salt. All

the raw ingredients were weighed according to the formulation. Cheddar cheese (Whitehall

specialties, Whitehall, USA) was weighed and cut into cubes. The weighed cheddar cheese was

kept at room temperature for an hour before it was used for process cheese manufacture. A

process cheese cooker was connected to the steam inlet and outlet hoses (2.15 kg/cm2) and the

pressure release valve was checked for its functionality. First, an anhydrous milk fat

(MidAmerica Farms, Springfield, Missouri) was added to the cheese cooker. After two minutes,

the cheddar cheese was mixed with the anhydrous milk fat in the cheese cooker. The mixture of

cheddar cheese and anhydrous milk fat was heated until the temperature reached 60 ºC. After the

temperature of the mixture reached 60 ºC, the mixture of salt (Cargill Inc., Minnesota) and

emulsifying salts (Cargill Inc., Minnesota) was added to the mixture. Five minutes after the

addition of the emulsifying salts, the pH of process cheese was measured using a pH meter

(Thermo Electron Corporation, Louisville, Colorado). For the adjustment of the pH to below

5.6, lactic acid (BK Giulini cor., Simi Valley, California) was added to the process cheese mass.

Once the temperature reached 84ºC, it was maintained for five minutes. The purpose of holding

the process cheese mixture at 84 ºC for 5 minutes was to ensure the microbiological safety of

process cheese by destroying the enzymes and pathogenic organisms. Next, sorbic acid

(Chemical supply, Miami, Florida) was added to the process cheese according to the formulation

27

for the preservative effect. After the addition of the sorbic acid, carotenal (International

Foodcraft Cor., Linden, New Jersey), which is a food color, was added to the process cheese.

The process cheese was packed into 5-lb paperboard loaf boxes (Green Bay Packaging., Green

Bay, Wisconsin) and stored at 10 ºC for further analysis.

Chemical Analysis of Process Cheese

Moisture content of process cheese. The moisture content of the process cheese

samples was analyzed using AOAC Official Method 926.08 Loss on drying moisture in cheese

(Horwitz, 2011). Weighed, 2-3 g samples of process cheese were transferred into a flat bottom

metal dish. The dish was then transferred to the oven (LR equipments, CA) and heated for four

hours at 100 ºC. After four hours of drying, the process cheese sample dish was transferred to a

desiccator and weighed to determine moisture loss. The moisture lost from the process cheese

sample was expressed as % moisture.

Fat content of process cheese. Process cheese samples were analyzed for fat content

(AOAC Official Method 920.125). Cheese samples were ground using a grinder (Rosle cheese

mill) and transferred to a large flask. Hot water was added by 1 ml/g of cheese and then sulfuric

acid was slowly added in the same amount to the process cheese. Samples were stored at room

temperature for 5-8 minutes in order to separate the fat from the protein mass, which was

transferred to the separator. After that, samples were filtered and dried for the % fat content

analysis.

Protein content of process cheese. Process cheese samples were also analyzed for

protein content (AOAC Official Method 2001.14). The Kjeldahl method consists of three steps

which include digestion, distillation and titration. Process cheese samples of 1 g were first

28

digested by dipotassium sulfate (K2 SO4) in the presence of copper copper sulfate pentahydrate

(CuSO4.5H2O). The sample was digested for one hour at 450 ºC. After that, distillation was

done by using a 50% sodium hydroxide (NaOH) solution. All of the distilled samples were

titrated using 0.1M hydrochloric acid (HCl). The end point of titration was determined by the

pink color of the sample.

% Nitrogen = [1.4007* (Vs-Vb )*M]/W

Where Vs and Vb were ml HCl titrant used for test portion and blank, respectively

M = Molarity of HCl solution; and W = test portion weight, g.

After determining the % Nitrogen, the protein content of process cheese samples was calculated

using the following formula:

% Protein= 6.38*Nitrogen %

Salt content of process cheese. Salt content of process cheese samples was determined

using the Quantab Chloride Titrator (AOAC Official Method 971.19). Process cheese samples

were weighed for 10 g and diluted using 10-15 ml distilled water. Diluted process cheese

samples were transferred to the Quantab chloride titrator. After 1-2 minutes, the test signal was

completely blue; this was an indication of completion of the reaction. After that, the reading on

the titrator was converted to the percentage NaCl by using the calibration table.

pH of process cheese. All process cheese samples were analyzed for pH. The pH meter

probe (Electron Corporation, Louisville, CO) was inserted into the process cheese samples and

the reading on the pH meter gave the direct values for the pH of the samples.

Meltability of process cheese. Meltability of process cheese samples was analyzed

using the Schreiber test. Circular cheese samples of 39.5 mm diameter and 5mm height were

29

placed into a Pyrex petri dish. These dishes were transferred to a forced draft oven, which was

heated to 232 ºC. Samples were taken out after 5 minutes and cooled at room temperature.

Melatibility of the process cheese samples was measured using a scale of 1-10 units on a circle

of six lines.

Microbiological Analysis of Process Cheese

The process cheese samples were also analyzed for microbiological food safety. The

microbiological analysis included Total plate counts (TPC), Coliform counts and Yeast and mold

counts.

Total plate count (TPC). Total plate counts of process cheese samples were done using

the AOAC Official Method 989.10. Each process cheese sample was diluted to a different

dilution, and all samples were analyzed in duplicate. The whole analysis was done in the laminar

air flow chamber. Process cheese samples were ground using the stomacher, and two different

dilutions were made: one at 1:10 and one at 1:100 using buffer solution. The diluted samples

were then transferred to petrifilm (3M Co., St. Paul, MN) and incubated for 24 hours at 37 ºC.

The colony was counted using the colony count meter.

Coliform count. The same diluted samples were used for the coliform count of process

cheese (AOAC Official Method 989.10). The dilution used for analysis was 1:10 and 1:100.

Diluted samples were placed on the coliform petrifilm (3M Co., St. Paul, Minnesota). Then the

petrifilms were transferred to the incubator for 24 hours at 37C. The coliform count was

conducted using a colony meter.

Yeast and mold count. Process cheese samples were also analyzed for yeast and mold

count (AOAC Official Method 989.10). Dilutions used for analysis were 1:10 and 1:100 for

30

process cheese samples. Potato dextrose agar (PDA) petrifilm (3M Co., St. Paul, Minnesota)

was used for the analysis of yeast and mold counts. The colony count was done using a colony

counter meter, and the formula used for the colony count follows:

N= ∑C / [(1xn1) + (0.1xn2)] d

N = number of colonies per mL

∑C = sum of all colonies on all plates counted

n1 = number of plates in lower dilution counted

n2 = number of plates in next higher dilution counted

d = dilution from which the first counts were obtained

Statistical Analysis

This study was conducted using completely randomized design with 4 replications and

the data were analyzed using SPSS software (version 19.0) provided by IBM Inc. Data were

reported as means and standard deviation of the means. One Way ANOVA was performed for all

the three process cheese samples (control, treatment 1and treatment 2) and the level of

significant used for Turkey’s mean difference was 5% (p ≤ 0.05).

31

Chapter IV: Results and Discussion

Effects on Chemical Characteristics

Process cheese samples were produced using three different emulsifying salts. The

Control (NaCl), Treatment1 (KCl) and Treatment 2 (NaCl+KCl) were analyzed for different

chemical attributes such as moisture, fat, protein, salt content, pH and meltability.

Table 2

Effect of Types of Salts on Chemical Characteristics of Process Cheese

a,b,c Means with different letters within the same column are significantly different (p≤0.05); n=4

Moisture. The moisture content of all three process cheese samples was analyzed, and

the details appear in table 3. Results of moisture content for all three control (NaCl), Treatment1

(KCl) and Treatment2 (NaCl+KCl) samples were 39.40 (SD=0.06), 39.90 (0.48) and 39.51

(SD=0.48). The results for moisture content analysis of process cheese samples were not

statistically significant (p>0.05). This result agrees with Cunha and Viotoo’s (2010) results,

which demonstrated that the effect of different emulsifying salts on moisture content of process

cheese was not statistically significant. Al-Otaibi et al. (2006) found the result that white salted

cheese made with a different emulsifying salt mixture had no effect on the moisture content. The

different phosphates and citrates, sodium or potassium, also had no effect on moisture content

Process Cheese Samples

Moisture (%)

Fat (%)

Protein (%)

Salt (%)

pH Meltability

NaCl 39.40a 31.39a 17.14a 2.10c 5.57a 6.00a

KCl 39.90a 30.57a 17.30a 1.25a 5.57a 5.62a

NaCl+KCl 39.51a 30.66a 17.25a 1.87b 5.55a 5.87a

32

(Al-Otaibi et al., 2006). Reddy and Marth (1993) determined the moisture content of cheddar

cheese made by different salts, which indicated that a change in salt did not affect the moisture

content.

Fat. The fat content of the three different process cheese samples is shown in table 3.

The fat content of the control (NaCl) sample was 31.39 (SD=0.63). Results of fat analysis for

Treatment1 (KCl) and Treatment 2 (NaCl+KCl) were 30.57 (SD=0.42) and 30.66 (SD=0.63)

respectively. The results of fat content analysis did not show a statistically significant difference

(p>0.05). The results of the fat analysis indicate that there was no significant effect from types

of salts used on the fat content of process cheese. El-Bakry et al. (2010) reported that types of

emulsifying salts used for process cheese manufacture did not statistically affect the fat content.

Al-Otaibi and other’s (2006) research supported the results of this study: changing the salt did

not affect the fat content of the process cheese samples. The result of this study also agreed with

Ayyash and Shah’s (2011a) finding that fat content did not show any effect based on changing

the type of salt from sodium chloride to potassium chloride.

Protein. Emulsifying salts had an ability to alter the protein structure and stabilize the

plastic mass. The results for protein content analysis of all three process cheese samples were

17.14 (SD=0.01), 17.30 (SD=0.01), and 17.25 (SD=0.03) respectively for the Control (NaCl),

Treatment1 (KCl) and Treatment 2 (NaCl+KCl). The results did not show a statistically

significant difference (p>0.05). Ayyash and Shah (2011b) stated that the protein content of

Halloumi cheese was not altered by the changing the emulsifying salt. The results of Reddy and

Marth’s (1993) research study also confirmed that there was no effect from using potassium

chloride as a salt (sodium chloride) replacer on the protein content of cheddar cheese. Katsiari et

al. (1998) reported that the protein content of Kefalograviera cheese was not affected by using

33

potassium chloride instead of sodium chloride. Ayyash and Shah (2011c) demonstrated that

replacing sodium chloride with potassium chloride had no effect on the protein content of low

moisture mozzarella cheese.

Salt. Salt content basically represents the amount of sodium present in the process

cheese samples. The results of the salt content analysis of process cheese samples were 2.10

(SD=0.06), 1.25 (SD=0.01), and 1.87 (SD=0.05) for Control (NaCl), Treatment1 (KCl) and

Treatment 2 (NaCl+KCl) respectively. The values for salt analysis were statistically significant

(p<0.05). The result of Gomes et al. (2011) study found a statistically significant difference in

the salt content of Minas fresh cheese made with different concentrations of potassium chloride

and sodium chloride. The result of this study agreed with those of Reddy and Marth (1993), who

reported that cheddar cheese made with potassium chloride had a different salt content than

cheese made with sodium chloride. Ayyash and Shah (2011a) reported that low-moisture

mozzarella cheese made with potassium chloride used for partial substitution of sodium chloride

had an effect on the salt content. El-Bakry (2012) reported that use of potassium chloride as an

emulsifying salt replacer had a significant effect on the salt content of process cheese.

Templeton and Sommer (1936) studied different emulsifying salts used for process cheese

manufacture and found that process cheese made with potassium chloride had an effect on salt

content.

34

Figure 1. Effect of Types of Salt on the % Salt Content of Process Cheese (abc represents the

statistical significant difference between treatments).

pH. According to the Food and Drug Administration (FDA), process cheese should have

a pH below or equal to 5.6. The results of pH measurement for three process cheese samples, the

pH values for the control (NaCl), Treatment1 (KCl) and Treatment 2 (NaCl+KCl) samples were

5.6 (SD=0.02), 5.6 (SD=0.01) and 5.5 (SD=0.02) respectively. It means that all pH values were

below the limit set by FDA regulation. The pH values of all three samples did not show the

statistical significant (p>0.05). El-bakry et al. (2010) reported the effect of the decrease in pH as

the level of salt decrease but it was not statistically significant. Here in this study the effect

might not be due to the types and composition of salts used for manufacture of process cheese.

The result from the research study of Karagozlu et al. (2008) supported that pH of the white

pickled cheese was not changed by the fully or partially replacement of sodium chloride with

potassium chloride.

0

1

2

3

NaCl KCl NaCl+KCl

34

Figure 1. Effect of Types of Salt on the % Salt Content of Process Cheese (abc represents the

statistical significant difference between treatments).

pH. According to the Food and Drug Administration (FDA), process cheese should have

a pH below or equal to 5.6. The results of pH measurement for three process cheese samples, the

pH values for the control (NaCl), Treatment1 (KCl) and Treatment 2 (NaCl+KCl) samples were

5.6 (SD=0.02), 5.6 (SD=0.01) and 5.5 (SD=0.02) respectively. It means that all pH values were

below the limit set by FDA regulation. The pH values of all three samples did not show the

statistical significant (p>0.05). El-bakry et al. (2010) reported the effect of the decrease in pH as

the level of salt decrease but it was not statistically significant. Here in this study the effect

might not be due to the types and composition of salts used for manufacture of process cheese.

The result from the research study of Karagozlu et al. (2008) supported that pH of the white

pickled cheese was not changed by the fully or partially replacement of sodium chloride with

potassium chloride.

0

1

2

3

NaCl KCl NaCl+KCl

35

Meltability. The ability of process cheese to melt upon heating was one of the important

parameters for the manufacture and end use of process cheese. The results for control (NaCl),

Treatment1 (KCl) and Treatment 2 (NaCl+KCl) process cheese samples were 6.00 (SD=0.40),

5.62 (SD=0.15), and 5.87 (0.17) respectively. The values did not show a statistically significant

difference (p>0.05). Shirashoji et al., (2010) reported that the type and amount of emulsifying

salts used for process cheese preparation did not affect the meltability. Ayyash and Shah (2011a)

also found that low-moisture mozzarella cheese made with a partial substitution of sodium

chloride with potassium chloride did not alter the meltability. Kamleh et al. (2012) reported the

effect of potassium chloride as a salt replacer on meltability of halloumi cheese.

Effect on Microbiological Characteristics

Microbiological analysis, including total plate counts (TPC), coliforms and yeast and

mold counts of process cheese samples was done to determine the effect of emulsifying salts.

Table 3

Effect of Types of Salts on Microbiological Characteristics of Process Cheese

Process Cheese Samples Total Plate Counts (TPC)

Coliform Counts Yeat & Mold Counts

NaCl 2.03a 1.39a 1.70a

KCl 2.34b 1.79b 2.07b

NaCl+KCl 2.19c 1.59c 1.89c

a,b,c Means with different letters within the same column are significantly different (p≤0.05); n=4

36

Figure 2. Effect of Types of Salts on Total Plate Counts (TPC), coliform counts, yeast and mold

counts of Process Cheese (abc represent the statistical significant difference between treatment).

Total plate counts (TPC). The results of total plate counts (TPC) for the Control

(NaCl), Treatment1 (KCl) and Treatment 2 (NaCl+KCl) samples were 2.03 (SD=0.01), 2.33

(SD=0.04) and 2.19 (SD=0.01). These results show a statistically significant difference (p <

0.05). Total plate counts (TPC) for the Control (NaCl) samples were lower than those of

Treatment 2 (NaCl+KCl), followed by Treatment1 (KCl). Bidlas and Lambert (2008) reported

that potassium chloride (KCl) had a lower antimicrobial effect than sodium chloride (NaCl) for

the purpose of salt replacement. The results of Kamleh et al. (2012) research study supported

that Halloumi cheese made with the potassium chloride (KCl) as a salt replacer had higher total

plate counts (TPC) than the sodium chloride (NaCl) salt replacer. Reddy and Marth (1995) also

found that cheddar cheese made with potassium chloride (KCl) had higher total plate counts

(TPC) compared to cheddar cheeses made with sodium chloride (NaCl). El-Shibiny (2007) also

found that process cheese spread produced with potassium chloride had a significant effect on

0

0.5

1

1.5

2

2.5

3

NaCl KCl NaCl+KCl

Total platecounts (TPC)

Coliformcounts

Yeast andMold counts

Log

37

total plate count (TPC). Sodium chloride (NaCl) had more ability to bind free water, which

means that water activity was lower than potassium chloride (KCl) and consequently, bacterial

growth was inhibited (Bidlas & Lambert 2008).

Coliform counts. Coliform counts of process cheese samples were determined. Control

(NaCl), Treatment1 (KCl) and Treatment 2 (NaCl+KCl) samples showed a statistically

significant difference in their results. The results of Control (NaCl), Treatment1 (KCl) and

Treatment 2 (NaCl+KCl) were 1.39 (SD=0.05), 1.78 (SD=0.02) and 1.58 (SD=0.03)

respectively. The process cheese made with potassium chloride (KCl) had a higher coliform

count than that of the mixture of sodium chloride plus potassium chloride (NaCl+KCl), followed

by sodium chloride (NaCl). The results from the study of Kamleh et al. (2012) indicated that

potassium chloride used as a salt (sodium chloride) replacer had a significant effect on the

coliform counts of Halloumi cheese. Reddy and Marth (1995) reported that potassium chloride

used for cheddar cheese manufacture had higher coliform counts than the sodium chloride.

Yeast and mold counts. Yeast and mold counts of the process cheese sample were one

of the important factors in quality determination. Process cheese samples were analyzed for

yeast and mold count. The results for all three process cheese samples were 1.69 (SD=0.05),

2.07 (SD=0.02) and 1.88 (SD=0.03). The results showed statistically significant differences

from each other. Bidlas and Lambert (2008) reported the effect of salt replacement on yeast and

mold counts. KCl used as a salt replacer in process cheese had an effect on yeast and mold

counts. Aly (1995) demonstrated the result that low sodium feta-type cheese produced with

potassium chloride had higher yeast and mold counts than those produced with sodium chloride.

The result of this study was in accordance with Kamleh et al. (2012), who found that potassium

chloride had a significant effect on yeast and mold counts. Reddy and Marth (1995) also

38

supported that cheddar cheese produced with potassium chloride had a higher yeast and mold

counts than those produced with sodium chloride.

39

Chapter V: Conclusions

The pasteurized process cheese samples were made using three different types of

emulsifying salts: a control (NaCl), Treatment 1 (KCl) and Treatment 2 (NaCl+KCl). The

process cheese samples were analyzed for chemical and microbiological characteristics to

determine the effect of salt replacement. With the exception of salt content, all other

characteristics showed no statistically significant difference. Replacing a salt did not have an

effect on the chemical characteristics of process cheese. Process cheese samples were also

analyzed for microbiological characteristics which included total plate counts (TPC), coliform

counts, yeast and mold counts. Salt replacement in process cheese had a significant effect on

microbial characteristics. The microbial analysis of process cheese samples indirectly indicated

the effect of salt replacement on the shelf life of process cheese. In conclusion, potassium

chloride had high possibility to use as a salt replacer without changing the chemical properties,

but it has limited ability to produce process cheese with same shelf life as process cheese made

with sodium chloride.

Recommendations for Further Study

Future research can be done based on the following recommendation to evaluate the

effect of salt replacement on chemical and microbiological characteristics of pasteurized process

cheese. Further manufacture of process cheese with a combination of potassium chloride (KCl)

and antimicrobial agents can extend the shelf life of process cheese same as sodium chloride

(NaCl). In this study potassium chloride (KCl) was used as a salt replacer; in the future it is

recommended to develop a process cheese either with a new source of salt replacer.

40

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