AN OPTIMIZATION OF MIXING PROCESS PARAMETERS FOR SOY SAUCE

PRODUCTION

NOORILYANA BINTI ABU BAKAR

A project report submitted in partial fulfilment of the

requirements for the award of the degree of

Master of Engineering (Industrial Engineering)

Faculty of Mechanical Engineering

Universiti Teknologi Malaysia

JUNE 2015

Buat Keluarga Tersayang

Mak abah

Jummelah binti Tahir

Abu Bakar bin Daud

Zaharah binti Othman

Keni bin Miskon

Abang-abang

Adik-adik

dan teristimewa buat suami

Khairul Luthfi bin Keni

serta anak-anak tercinta

Muhammad Althof bin Khairul Luthfi

Muhammad Afiq bin Khairul Luthfi

Muhammad Alfatih bin Khairul Luthfi

Terima kasih atas segalanya!

ACKNOWLEDGEMENT

First and foremost, all praise be to Allah, the Mighty, the Benevolent for His

blessings and guidance for giving the inspiration to embark on the project and instilling the

strength to see that the report project becomes a reality. Many people have contributed to

the creation and completion of this book. I would like to express my gratitude to my

project’s supervisor, Associate Professor Dr. Adnan bin Hassan for his valuable guidance,

encouragement, attractive ideas, information, illustration and advice throughout the

completion of this project and hopes the Al – Mighty will make his life so pleasant.

Thank you to my family who gave so much support, encouragement, inspiration and

always pray for my success. Very special thanks to Puan Noryanti binti Kasnan, Quality

Controller of Zara Foodstuff Industries Sendirian Berhad who have given me a golden

opportunity to complete this project at her company and always guide, advice and assist me

to the completion of this project.

I would like also to dedicate this project report to all my friends who have always

shown great comfort in those stressful days with their advice, care and support. To the

Faculty of Mechanical Engineering and Perpustakaan Sultanah Zanariah’staffs, my

lecturers in Universiti Teknologi Malaysia (UTM) and anywhere in the world, thanks for

your valuable help and understanding. May Allah bless you all.

ABSTRACT

This research was done to reduce the variation of brixs in mixing process to produce

sweet soy sauce. The objective of this research is to find the optimum setting in mixing

process. Design of Experiment was used to analyze various combination of process

parameters. The process parameters investigated were sugar, caramel, monosodium

glutamate (MSG) for Experiment 1 and sugar, salt, water, acid acetic for Experiment 2

respectively. It was not economically practical to run experiments in the real life factory

environment. As such, lab experiment was used in this study. Full factorial of design matrix

has been used. The significant factors for Experiment 1 are sugar, MSG and caramel. This

is including two way interactions between sugar and MSG, Sugar and caramel, MSG and

caramel and the last one is three way interaction of all factors. Normally, 3 way interaction

and above are assumed as insignificant factors. The significant factors for Experiment 2 are

sugar, salt, water and caramel. This is including two way interactions between sugar and

salt, Sugar and acetic acid, salt and acetic acid, water and acetic acid and three way

interaction between sugar, salt and water and last three way interaction are sugar, water and

acetic acid. The study reveals that the optimum setting is the low level (-1) of sugar

(450~500 kilogram), caramel (200~225 kilogram) and MSG (64~68 kilogram) for

Experiment 1. The optimum setting for Experiment 2 is the low level (-1) of sugar

(1350~1450 kilogram), salt (45~55 kilogram), and acetic acid (0.35~0.45 litres) but higher

level (+1) for water (800~900 litres) in order to ensure the brix reading fulfil the

specification. Mathematical models have been proposed to predict the performance of

mixing process with brix reading as the response within the investigated ranges. There are a

few suggestions and suitable action plan were proposed to increase the quality of

production.

ABSTRAK

Kajian ini dijalankan untuk mengurangkan variasi ke atas bacaan brix di dalam

proses campuran menghasilkan kicap soya manis. Objektif utama kajian ini adalah untuk

mencari pemboleh ubah yang optima dalam proses ini. Rekabentuk Eksperimen telah

digunakan untuk menganalisa pelbagai gabungan pemboleh ubah dalam proses ini.

Pemboleh ubah yang dikaji adalah gula, caramel dan perasa monosodium glutamate (MSG)

untuk Eksperimen 1 dan gula, garam, air serta asid asetik untuk Eksperimen 2. Tidak

praktikal dari segi ekonomi untuk menjalankan eksperimen sebenar seperti di kilang

melainkan eksperimen makmal digunakan. Faktorial penuh digunakan dalam eksperimen

ini. Faktor-faktor yang ketara untuk Eksperiman 1 adalah gula, MSG dan caramel, interaksi

dua hala adalah antara gula dan MSG, gula dan karamel, MSG dan karamel dan yang

terakhir interaksi tiga hala adalah melibatkan ketiga-tiga faktor iaitu, gula, MSG dan

karamel. Kebiasaannya, interaksi 3 hala atau lebih adalah dianggap sebagai faktor yang

tidak penting. Untuk Eksperimen 2, faktor-faktor yang ketara adalah gula, garam, air dan

asid asetik, interaksi dua hala pula menunjukkan perkaitan antara gula dan garam, gula dan

asid asetik, garam dan asid asetik, air dan asid asetik manakala untuk interaksi 3 hala pula

melibatkan interaksi antara gula, garam dan air serta gula, air dan asid asetik.

Kebiasaannya, interaksi tiga hala adalah dianggap sebagai faktor yang tidak penting. Hasil

daripada kajian ini, pemboleh ubah yang optima adalah nilai rendah (-1) pada gula

(450~500kilogram), karamel (200~225kilogram) dan MSG (64~68kilogram) untuk

Eksperimen 1. Penetapan nilai optimum untuk Eksperimen 2 pula adalah nilai rendah (-1)

untuk gula (1350~1450kilogram), garam (45~55kilogram) dan asid asetik(0.35~0.45litres)

tetapi nilai tinggi (+1) adalah untuk air (800~900liter) untuk memastikan bacaan brix

adalah memenuhi spesifikasi yang ditetapkan. Matematik model telah dicadangkan untuk

menganggar keupayaan proses campuran dengan mengunakan brix sebagai respon dan

beberapa eksperimen telah dijalankan. Beberapa cadangan telah dikemukakan untuk

meningkatkan kualiti pengeluaran

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENTS iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

1 INTRODUCTION

1.1 Background of Project 1

1.2 Problem Statement 3

1.3 Objectives of the project 3

1.4 Scope of the Project 3

1.5 Methodology of the Project 4

1.6 Expected Result 4

1.7 Summary 5

2 LITERATURE REVIEW

2.1 Introduction 6

2.2 Quality 6

2.3 Statictical Process Control (SPC) 9

2.4 Design of Experiment Process 20

2.5 Effects to the Process Mean Shift and Variation 28

2.6 Soy Sauce Production Process 30

2.6.1 Plant-based Fermentation 33

2.6.2 Raw Material Preparation 34

2.6.3 Koji 34

2.6.4 Mashing 35

2.6.5 Fermentation 35

2.6.6 Pressing and Refining 35

2.7 Related Previous Work 36

2.8 Summary 37

3 BACKGROUND OF COMPANY

3.1 Introduction 39

3.2 Organizational Chart 41

3.3 Quality Policy 41

3.4 Product of Zara Foodstuff Industries Sdn. Bhd. 42

3.4.1 Soy sauce 42

3.4.2 Process Flow of Fermentation 43

3.4.3 Soy Sauce Manufactuting Process 45

3.5 Methodology of the Project 46

3.6 Summary 50

4 CHARACTERIZATION OF EXISTING CONDITION AND

PROBLEM IDENTIFICATION

4.1 Current Monitoring process in industry 51

4.2 Characterization of Existing Condition 52

4.3 Variation of Brix 52

4.4 Process Variation and Process Capability 54

4.5 Issues in Optimization 56

4.6 Factor, Levels and Ranges Selection 57

4.7 Summary 59

5 DESIGN OF EXPERIMENT AND DATA ANALYSIS

5.1 Introduction 60

5.2 Selection of Factors 60

5.3 Design of Experiment for Ingredient B (Experiment 1) 62

5.3.1 Main Effect and Interaction Analysis 64

5.3.2 Normal Probability and Pareto Chart 65

5.3.3 Factorial Fit and ANOVA 67

5.3.4 Residual Plot 68

5.4 Design of Experiment for Ingredient C (Experiment 2) 70

5.4.1 Main Effect and Interaction Analysis 72

5.4.2 Normal Probability and Pareto Chart 74

5.4.3 Factorial Fit and ANOVA 74

5.4.4 Residual Plot 77

5.5 Summary 78

6 RESULT AND DISCUSSION

6.1 Introduction 79

6.2 Confirmation run for Experiment 1 79

6.3 Confirmation run for Experiment 2 81

6.4 Discussion of Result 83

6.5 Summary 83

7 CONCLUSION AND RECOMMENDATION

7.1 Conclusion 84

7.2 Recommendation 85

7.2.1 Suggestion for further research 85

7.2.2 Suggestion to Industry 85

REFERENCES

LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Types of soy sauce (Robert, 2008) 33

2.2 Summary of Past Research on Optimization in Food Process 38

4.1 Lab test for sweet soy sauce , July 2014 53

4.2 company specification for Brix, pH and Specific Gravity 54

5.1 Range and Level of Factors for Experiment 1 67

5.2 Experimental design matrix for Experiment 1 68

5.3 Full Factorial Fit and ANOVA for brix value 72

5.4 Range and Level of Factors for Experiment 2 75

5.5 Experimental design matrix for Experiment 2 76

5.6 Full Factorial Fit and ANOVA for brix value 80

6.1 Result confirmation run for Experiment 1 80

6.2 Summary of result Experiment 1 81

6.3 Result confirmation run for Experiment 2 81

6.4 Summary of result Experiment 2 82

7.1 Best setting for Soy Sauce Mixing Parameters 84

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1 Areas responsible for quality (Source: Besterfield, 2004) 9

2.2 Pareto Chart 13

2.3 Cause and Effect Diagram 13

2.4 Check Sheet 14

2.5 Process Flow Diagram 15

2.6 Scatter Diagram 16

2.7 Histogram 17

2.8 Control Chart 18

2.9 Causes effect to process mean and variance (Montgomery, 1996) 29

2.10 Soy and wheat with Aspergillus sojae cultures to brew soy sauce 32

3.1 Building of Zara Foodstuff Industries Sdn Bhd 39

3.2 Organizational Chart of Zara Foodstuff 41

3.3 Fermentation process flow for soy sauce 43

3.4 Process Flow of soy sauce manufacturing process 45

3.5 Steps of Project Implementation 47

4.1 Illustrates the Refractometer 52

4.2 Individual chart for Brix , July 2014 53

4.3 EWMA chart of data 55

4.4 Histogram of current Brix and USL,LSL line 56

4.5 Cause and effect diagram for Brix reading 57

5.1 Ingredient in Mixing Process 61

5.2 Factors need to be controlled 61

5.3 Mixing in lab scale using overhead stirrer 62

5.4 Main Effect Plot for Brix (Experiment 1) 64

5.5 Interaction plot for Brix value (Experiment 1) 65

5.6 Normal Probability Plot (Experiment1) 66

5.7 Pareto Chart (Experiment 1) 66

5.8 Residual Plot for Brix value 69

5.9 Main Effect Plot for Brix (Experiment 2) 72

5.10 Interaction plot for Brix value (Experiment 2) 73

5.11 Normal Probability Plot (Experiment 2) 73

5.12 Pareto Chart (Experiment 2) 74

5.13 Residual Plot for Brix value 77

1

CHAPTER 1

INTRODUCTION

1.1 Background of the Project

In general, companies compete on three main issues: quality, price and

delivery. This is true for all types of organizations, whether they are in

manufacturing, services or public sector (Ho and Fung, 1994). Moreover, the

business trend nowadays has also shifted to the global market. Competition is

becoming more intense especially when there will be no more trade barrier and

national boundary.

Statistical Process Control (SPC) plays a major part in the efforts of many

organizations and industries to improve the competitiveness of their products,

services, prices and deliveries. SPC is an effective approach to problem solving and

process improvement or even stop producing chaos ( Oakland, 2010). In continuous

production activity, usually seven basic SPC tools such as flow chart, check sheet,

scatter plot, control chart, histogram, Pareto analysis and Ishikawa fish bone chart are

applied concurrently. Control charts are classified to the variable and attribute control

charts. Control chart for variables consists of several types such as Shewhart X-bar,R

and X-bar,S, Cumulative sum (Cusum), exponentially weighted moving average

(EWMA), individual moving range and others. Control charts function as the

statistical method to monitor and control the process variable or attribute within the

computed or historical control limits. Control limits are usually computed based on

drawing specification, machine capability or historical process mean and standard

2

deviation. Most production practices will use the tightened control limits which are

1.33 times smaller than the specification limits. For stable process, a centerline

between these two control limits need to be maintained continuously. Basically,

control charts acts to monitor a process by signals any plotted data that is out from

the control limits.

Soy sauce is a dominant savory in Asian dietary. In order to ensure the taste

and the aroma is maintained delicious and exotic, the ingredient and the procedures to

manufacture the soy sauce must be standards and comply with the food safety control

system. Soy sauce (also called soya sauce) is a condiment made from a fermented

paste of boiled soybeans, roasted grain, brine, and Aspergillus oryzae or Aspergillus

sojae molds. After fermentation, the paste is pressed, producing a liquid, which is the

soy sauce, and a solid byproduct, which is often used as animal feed. Soy sauce is a

traditional ingredient in East and Southeast Asian cuisines, where it is used in

cooking and as a condiment. It originated in China and spread throughout Asia. Soy

sauce has a distinct yet basic taste of umami, due to naturally occurring free

glutamates (Khaterine,2003).

Varieties of soy sauce are salty, earthy, brownish liquids intended to season

food while cooking. Many kinds of soy sauce are made in Japan, Taiwan, China,

Korea, Indonesia, Vietnam, Malaysia and other countries. Variation is usually

achieved as the result of different methods and durations of fermentation, different

ratios of water, salt, and fermented soy, or through the addition of other ingredients.

This study focused on soy sauce company, Zara Foodstuff Industries Sdn Bhd

current practice shows that the company did not measure the ingredients because they

believe that the total weight stated at every pack of raw material is accurate. This

situation could affect the variability of brix value of sweet soy sauce. In order to

improve the quality of brix, design of experiment adopted as analyzed tools.

3

1.2 Problem Statement

Mixing is the main process to combine several ingredients. In order to

produce a good soy sauce, the company need to control the brix value range from 63-

65 Brixo. The process of mixing the ingredients has resulted in high variability in the

brix value. Sometimes, there is too much quantity of sugar that produced high

reading in brix and sometimes, the quantity of salts is too high. Currently this

problems has been addressd by try and error. Sugar is added if too salty and soy

water is added if it too sweet until they get the standard specification. This method is

not systematic and lack of consistency. The variability of brix suggests that the

company needs to improve its problem solving technique as ample time is wasted

through try and error method.

The variability of brix reading is the focus problem in this project. The aim of

this project is to reduce the process variability by investigating its optimum parameter

setting

1.3 Objectives of the project

The objectives of the project are:

(i) To identify the problem in a Sweet Soy Sauce process.

(ii) To study key process parameters and their influences on the Brix reading.

(iii) To obtain an optimal setting of process parameter for Brix to fulfill the

product specification.

1.4 Scope of the Project

This project was carried out to monitor the manufacturing process for Zara

Foodstuff Industries focusing on the following areas:

4

(i) This study focus on Mixing process

(ii) Only brix reading will be studied as the quality response

(iii) Focus on sweet soy sauce

(iv) Will not include cost monitoring

(v) The Classical Design of Experiment is employed

This project provides suggestions for the way forward to the case company in

monitoring the soy sauce mixing process.

1.5 Methodology of the Project

The project methodology is based on several steps that allow the project to be

done systematically. The methodology started with the characterization of existing

process and followed by planning the experimental design. After that, the experiment

was conducted by using statistical method and will be discussed in Chapter 3.

1.6 Expected Result

The Design of Experiment approach adopted in this study is expected to

reduce process variability problems faced by manufacturer and to gather details

information about the interaction between process parameters. Thus, the values of

process parameters can be arranged according to the desired characteristics. The

statistical design approach gives an opportunity to fully understand the effects of

process parameters on desired brix reading by performing significantly fewer

experiments than if one factor at a time had been evaluated. A good understanding of

how interactions among the various factors influence the brix reading of soy sauce

specimens will be obtained. Again, this information would not have been indicated if

one factor at a time had been investigated. Accurate relationships, describing the

effects of the various factors on brix reading will be obtained by using design of

experiment approach. The aim of this project is to improve the quality of product by

5

reducing the variation of brix reading. When the performance is constantly closer to

the target, fewer products are produced out of target. Meaning that the products are

produced within specification limits or in this case study products are within

Guaranty Limits.

1.7 Summary

This chapter introduces the problem in the case study company, Zara

Foodstuff Industries Sdn. Bhd. The variability of brix reading is the focus problem.

The aim of this project is to reduce the process variability by investigating its

optimum parameter setting.

6

CHAPTER 2

LITERATURE REVIEW

2.1 Introduction

There are several aspects that will be covered in this chapter which are the

Quality, Statistical Process Control (SPC), process, control and Design of

Experiment (DOE) to be more related to food processing regarding the case study

company are manufacture of food product.

For the quality, the definition of quality from several gurus will be explained.

A detailed explanation on quality procurement will be given. The next issue is

regarding SPC definition, function and the important role in manufacturing. The

main topic relating to process monitoring will also be discussed.

Consecutively, the basis on what should consist in process monitoring will be

explained using the SPC method focused on requirements that relatives to the

process.

2.2 Quality

Nowadays, the word quality appears on almost in every product such as food,

automobiles and software. No matter where people go, they will see or hear about

quality. In fact, people demand a certain level of quality in everything that they want

86

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