Master of Technology

99 Pages·2012·0.91 MB·English

MOISTURE SORPTION ISOTHERMS OF
THE TRADITIONAL INDIAN DAIRY PRODUCT
“HALVASAN”
A
THESIS
SUBMITTED TO THE
ANAND AGRICUTURAL UNIVERSITY
IN PARTIAL FULFILMENT OF THE REQUIREMENTS
FOR THE AWARD OF THE DEGREE
OF
Master of Technology
IN
DAIRY ENGINEERING
BY
GADHAVI JAYRAJSINH HIMMATSINH
B.TECH (DAIRY TECHNOLOGY)
DEPARTMENT OF DAIRY ENGINEERING
S.M.C. COLLEGE OF DAIRY SCIENCE
ANAND AGRICULTURAL UNIVERSITY
ANAND – 388 110
2015
REGISTRATION NO. 04-2009-2012
MOISTURE SORPTION ISOTHERMS OF
G
THE TRADITIONAL INDIAN DAIRY PRODUCT
A
D
“HALVASAN”
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ANAND – 388 110

2 2015
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1
5
REGISTRATION NO. 04-2009-2012
MOISTURE SORPTION ISOTHERMS OF THE
TRADITIONAL INDIAN DAIRY PRODUCT
“HALVASAN”
Name of Student Major Advisor
Gadhavi Jayrajsinh H Dr. A. G. Bhadania
Reg. No: 04-2009-2012 (Professor and Head)
SMC COLLEGE OF DAIRY SCIENCE
ANAND AGRICULTURAL UNIVERSITY
ANAND-388110
ABSTRACT
Water is an important component of all food products. It is important for the
storage stability. It depends on interaction between water and other components of the
food product. The active part of water is much more important for the stability of food
product, than the total amount of water present. This way, knowing the water activity
of the product is very important part by means of chemical and microbial changes in
foods. Thus, it is possible to develop generalized rules or limits for the stability of
food products by using water activity as a parameter. This was, it is considered as one
of the most important parameter in food preservation and processing, because several
preservation techniques are based upon the lowering the active water content to
improve the stability of the food material against microbial growth. To completely
understand the relation between water and other components in a product it requires
an understanding of amount of water present in the food material. Such understanding
helps to improve the shelf life of the food materials. This can be derived by the study
of the moisture sorption isotherms at different temperatures. The comprehended water
activity contributes to protected food storage conditions and forms the basis of
modern food formulations, especially for the intermediate moisture foods.
Halvasan is one of the popular heat desiccated cereal based indigenous milk
sweets manufactured in large scale by many shop keepers in Khambhat region of
Gujarat State in India and it is sold in many parts of Gujarat and abroad. The product
resembles to doda burfi (in north region in Rajasthan), ghevar and sohan halwa in
many aspects. It is generally consumed fresh, as it has a limited shelf-life of 3-4 days
under ambient conditions. The objective of the study was to obtain the sorption
i
characteristics of halvasan prepared from standardized milk and germinated wheat
fada.
The moisture sorption characteristics of halvasan prepared from standardised
milk were determined by using static gravimetric method at 15, 25 and 35ºC and
various range of water activity (a ) from 0.11 to 0.97. The isotherms obtained were of
w
type II sigmoid shape. All isotherms shows that EMC at given water activity
decreases with increase in temperature. The EMC also shows an increase as the water
activity increases. GAB, Caurie, Oswin, Modified Mirzai and Haslay models were
applied to the experimental isotherm data of halvasan. Out of these five models, GAB
model shows the best fit to the data with minimum %RMSE values. Thus, the GAB
model is selected as best suitable model for the product halvasan.
The difference between equilibrium moisture content of halvasan in
adsorption and desorption was found to be statistically significant. The hysteresis loop
was classified as type C according to Everett and Whitton classification (Kapsalis,
1981), and it extended in the range of 0.1 to 0.9 range of water activity. Maximum
hysteresis was found in between the water activity range of 0.40 to 0.75. The
hysteresis effect decreased with increase in the temperature, which is quantified in
term of hysteresis units. The hysteresis units decreased with increase in temperature
from 2.64 units at 15ºC to 1.20 units at 35ºC.
Hysteresis amplitude ratio for halvasan was found in the range of maximum
value for this ratio in halvasan was 0.016 at 15ºC. It reduced with increase in
temperature to 0.014 at 25ºC and 0.012 at 35ºC. The determination of net isosteric
heat was done by Clausius- Clapeyron equation. Isosteric heat of sorption was found
to decrease with increase in moisture content and the trend seemed to become
asymptotic as the moisture content of above 20% dry basis was approached. The
maximum isosteric heat of sorption obtained was 30.57 kJ/mol for adsorption and
57.26 kJ/mol for desorption of halvasan. The results also showed that the adsorbed
monolayer moisture content of halvasan decreased from 8.22 at 15ºC to 6.43 g/100 g
solids at 35ºC. Similarly, desorption monolayer moisture decreased from 11.36 at
15ºC to 7.85 g/100 g solids at 35ºC.
ii
SHETH M. C. COLLEGE OF DAIRY SCIENCE
ANAND AGRICULTURAL UNIVERSTITY
ANAND - 388 110
Dr.A. G. Bhadania
Professorand Head
Department of DairyEngineering
S.M.C. College of Dairy Science
Anand Agricultural University
Anand-388 110
CERTIFICATE
This is to certify that the thesis entitled “Moisture sorption isotherms of the
traditional Indian dairy product ‘halvasan’” submitted by Mr. Gadhavi Jayrajsinh
Himmatsinh (Reg. No. 04-2009-2012) in partial fulfillment of the requirements for the
award of the degree of Master of Technology in Dairy Engineering, Anand Agricultural
University is a faithful record of bonafide research work carried out by him under my
personal guidance and supervision and the thesis has not previously formed the basis for the
award of any degree, diploma or any other similar title.
Place : Anand (Dr.A. G. Bhadania)
Date : /06/2015 Major Adviser
ACKNOWLEDGEMENT
I would like to express my deep sense of gratitude to my Major Guide Dr. A. G.
Bhadania, Professor and Head, Department of Dairy Engineering, Sheth M. C. College of
Dairy Science, Anand Agricultural University, Anand. I feel extremely blessed and fortunate
to have Sir as my guide. I hereby take this golden opportunity to express my sincere gratitude,
indebtedness and heartily regards to him for his valuable and ever inspiring guidance, critical
suggestions and his support and encouragement throughout the course of my study. I am also
thankful to him for giving the inventive idea for the research work and the research plan for
the present study. Iwould remain indebted forever.
I pay my due respect to Dr. J. B. Prajapati, Principal, S.M.C. College of Dairy
Science, Anand Agricultural University, Anand, and Dr. B. P. Shah, Ex-Principal, S.M.C.
College of Dairy Science, Anand Agricultural University, Anand,for the facilities provided.
I am very grateful to Dr. (Ms.) S. V. Pinto, (Minor Advisor), Associate Professor,
Department of Dairy Technology, S.M.C. College of Dairy Science, Anand, for her timely
suggestions and guidance whenever required. I am also thankful to Dr. P. S. Prajapati,
Ex-Professor and Head, Department of Dairy Technology, S.M.C. College of Dairy Science,
Anand for extending the facilities available at Dairy Technology Department without which
my study would have been anunmanageable venture.
I extend my sincere thanks to Dr. J. B. Upadhyay (Professor), Dr. Sunil Patel
(Associate professor), Er. C. S. Baladiya, Er. J. B. Raol, Er. Ashish Patel and Er. I. A.
Chauhan, (Assistant Professors) from Department of Dairy Engineering, Dr. H. G. Patel,
Professor and Head, Department of Dairy Plant Processing, Dr. A. H. Jana, Professor and
Head, Department of Dairy Technology, Prof. A. M. Patel and Prof. Dhinal Patel (Assistant
Professors), Department of Dairy Technology for their ever-being cooperation and invaluable
suggestions throughout the course of study. I was fortunate to have such a cooperative
departmental staff.
I am highly thankful to Mr. V. B. Darji, Associate Professor, Statistician, College of
Agricultural Information Technology, Anand Agricultural University, Anand for proper
guidance in analyzing the research data.
The cooperation and help given by Late Mr. Ramanbhai, Mr. Rakesh and Mr. Dinesh
from Dairy Engineering Department is also acknowledged. I would also extend my greetings
to Mr. Dineshbhai. M. Patel of Dairy Technology Department for important and
unforgettable help.
The delimited words hamper to express the feeling of my indebtedness to my friends
whose love and affection which made me fight against all odds encountered during the course
of study. They are and will ever be in my heart with all the sweet moments spent together. I
discovered the ever untouched corners of my heart because of them only. Unfortunately, I
have less space to name all, but I would like to pen down some of my friends Rohit, Vishal
Hitesh, Dinesh, Ronak, Tejas, Montu, Sharad, Denzil, Amit, Hetal, Moumita and Priyanka,
I would like to offer a heartfelt appreciation to my seniors especially Vivek Kosta,
Deepak Desai, Anil Chaudhari and Ashok Chaudhari for their help and emotional support. I
would thank my juniors Ashwin, Mahesh, Tridev and Rashmi who toiled with me during the
exhaustive days of study. I can never forget to mention my friends and mentors Mr. Jay
Bhatt, Ms. Krupa Hirpara, Mr. Gajanan Deshmukh and Prof. Shreyash Patel for their
everlasting and invaluable help andsupport till the end.
The Blessings of my Grandmother, my father Mr. H. D. Gadhavi, my mother Dr.
Ashaben Gadhavi and affection of my brother Anirudh and all my cousins who always have
been with me. I can’t forget to mention my wife, Divya, who has always stood by myself
during good and odd times. The words and actions will always fall short to thank them for
their belief and patience. With all my love and respect, I dedicate this work to them.
Above all, I bow before The Almighty, who provided me the strength to make this
venture, a successful one from its conception to its completion.
Allothers mightnotbementioned, but none is forgotten.
Place :Anand (Jayrajsinh Gadhavi)
Date: .06.2015
ii
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CONTENTS
Chapter PAGE
TITLE
No. NO.
1 INTRODUCTION 1-4
2 REVIEW OF LITERATURE 5-29
2.1 Halvasan 7
2.1.1 Mechanization of halvasan making 7
2.1.2 Physico-chemical characteristics 8
2.1.3 Texture profile and microbial characteristics 8
2.1.4 Sensory attributes 9
2.1.5 Storage related changes in halvasan at ambient
9
temperature
2.1.5.1 Physico-chemical changes during storage
9
2.1.5.2 Microbial changes during storage
10
2.1.5.3 Texture changes duringstorage
10
2.1.5.4 Sensory changes during storage
11
2.2 Water activity
11
2.2.1 Equilibrium moisture content 12
2.2.2 Moisture sorption isotherm 13
2.2.3 Measurement of moisture sorption isotherm 15
2.2.4 Moisture sorption isotherms of food materials 16
2.2.5 Food composition effects on moisture sorption
21
isotherms
2.2.6 Isotherm models 22
2.3 Temperature dependence of isotherm 23
2.4 Thermodynamic aspect of wateractivity
25
2.5 Moisture sorption hysteresis
27
3 MATERIALS AND METHODS 30-45
3.1 Preparation of experimental product 30
3.2 Analysis of milk 32
3.3 Proximateanalysis of halvasan 32
3.3.1 Moisture 32
3.3.2 Fat 32
3.3.3 Total protein 33
3.3.4 Sugar (reducing and non-reducing) 34
3.3.4.1 Lactose (reducing sugar) 34
3.3.4.2 Sucrose (non-reducing sugar) 34
3.3.5 Total ash 35
3.3.6 Titratableacidity 35
3.3.7 Water activity (a ) 36
w
3.4 Establishing moisture sorption isotherm 36
3.4.1 Sorption apparatus 36
3.4.2 Selection of salts for maintaining different humidity 40
3.4.3 Selection of temperature 41
3.4.4 Sorption procedure 41
3.5 Fitting of experimental data to isotherm equation 42
3.5.1 Accuracy of fit 43
3.5.2 Calculation of net isosteric heat of sorption 44
3.5.3 Temperature dependence of isotherm parameters 44
3.6 Evaluation of moisture sorption hysteresis 45
3.6.1 Moisture sorption hysteresis 45
3.6.1.1 Hysteresis amplitude 45
3.6.1.2 Hysteresis units 45
4 RESULT AND DISCUSSION 46-67
4.1 Chemical analysis of halvasan 46
4.2 Equilibrium moisture content 47
4.3 Sorption isotherms ofhalvasan 48
4.3.1 Adsorption and desorption isotherms ofhalvasan 48
4.3.2 Effect of temperatures on isotherms 52
4.4 Evaluation of moisture sorption hysteresis 57
4.5 Modelingofisotherms 60
4.6 Evaluation of net isosteric heat of sorption 64
5 SUMMARY AND CONCLUSION 68-72
REFERENCES i-xi
APPENDICES i-ii