(THE COOKING PROPERTIES OF THE DIFFERENT RICE
VARIETIES)
SUBMITTED TO
DEPARTMENT OF FOOD SCIENCE AND
TECHNOLOGY FACULTY OF AGRICULTURE AND NATURAL RESOURCE MANAGEMENT (FARM)
IN PARTIAL FULFILLMENT FOR THE AWARD OF
BACHELOR OF SCIENCES B.SC. IN FOOD SCIENCE AND TECHNOLOGY
ABSTRACT
Nine
rice varieties obtained from the Abakaliki rice Mill were used for this study.
Significant sanation (p<0.05) was deflected among the nine rice varieties
for all the parameters evaluated. The results obtained showed that the length,
cooking time, water uptake ratio, solid in cooking volume expansion and grain
elongation during cooking ranged between 0.38-0.81mm, 50.45-93.50mins, 7.16-11.02,
0.09-0.65g, 250-4.50mm and 2.50-0.81mm respectively. The values for the
amylore, emylopectin and starch content ranged between 5-31%, 69-95% and
23.5%-78.3% respectively. Sensory evaluation showed a significant difference
(p<0.05) in the quality of the rice samples and the overall acceptability
among the rice samples.
TABLE OF CONTENTS
Title page
Dedication
Acknowledgement
Table of contents
CHAPTER ONE
1.0 Introduction
CHAPTER TWO
2.0 Literature Review
2.1 History of Rice
2.1.1 Rice Varieties
2.1.2
Flow chart on how rice is been processed
2.1.3 Nutritional composition of rice
2.2 Source and Utilization of starch
2.2.1 Starch
2.2.2 Chemical composition of Starch
2.2.3 Chemical Starch Modification
2.2.4 Types of Starch Molecules
2.2.5 Starch properties
2.2.6 Starch components and molecular weights
of rice oryzenin
2.3 Amylose Content
2.3.1 Amylose Content Affects Rice Cooking
and Eating Quality
2.3.2
Effect of Cooking
2.4 Grain Shape
2.5 Rice product
2.6 Rice Quality
2.7 Factor Affecting Quality of Rice
CHAPTER THREE
3.0 Material and Method
3.1 Chemical Analysis
3.1.1 Determination of starch content
3.1.2 Amylose and Analypectin Content Determination
3.2 Physical Analysis
3.2.1 Sensory Evaluation
3.3 Cooking properties
3.3.1 Cooking Time
3.2.2 Gelatinization time and Gelatinization
temperature
3.2.3 Length and Width Determination
3.2.4 Length and Width Ratio
3.25 Volume Expansion
References
CHAPTER ONE
Rice is the most important cereal for human
consumption. It is the staple for over three billion people, constituting over
half of the world’s population (FAOSTAT 2006, purse glove 1972). It is consumed
mostly as intact grains except hulls, bran and germ. It is very rich in
carbohydrate and is also an important
topical cereal which also supplies a garters of the entire calorie in take
of the human race.
Rice
is an economic crop, which is important in household food security, ceremonies,
nutritional diversification, income and employment. It is utilized mostly at
the household level, where it is consumed as boiled or fried or grand rice with
stew or soup. Rice is cooked by washing and
boiling in water which leads to loss of some nutrients (Abulude 2004).
Rice is grown in all the ecological
and dietary zones of Nigeria. with different varieties, processing adaptations
traits for each ecology (Sanni et al, 2005) Despite the fact that different
varieties of rice are widely cultivated in Nigeria, each variety is quite
distinct in terms of their cooking characteristic. This is related to the
Nature and type of starch the grains contains. There are two types of starch in
rice, amylose and amylopectin. Amylase is a long, straight starch molecule that
does not gelatinize during cooking, so rice which contains more of this starch
tends to cook fluffy, with separate grains (Damion and Ben 2006). Rice that is
high in amylopectin has a lower glycemic index number (Bhattacharva 1997)
Amylopectin is a highly branched
molecule that makes the rice sticky when it’s being released form the grain
during cooking. Medium grain rice has more amylopectin making it a good
candidate for salads and rice pudding, which are served cold and short grain
rice has even more amylopectin and little to no amylase, so its used most often
for Asian cooking, when you want grains to be sticky so they are easier to eat
with chopsticks. Then there’s glutinous rice, which is vary sticky when cooked
with the highest amount of amylopectin and no amylose (Houston 1997).
Rice starch has by for the smallest
particle of all commercial starches. The average rice Starch granule is between
2-8 microns rice starch is also known to have the whitest colour of all the
starches. /rice starch is easily digested. The relevant literature quotes a
digestibility rate of between 98 and 100%. Rice starch are known for the soft
gel and creamy mouth feel. They have widely used as fat replaces in wide range
of food product, waxy rice starches can be used at low level in food to create
the sensation of ricer and higher fat product.
The
objectives of this work are:
(i) To
determine the cooking properties of the different rice varieties
(ii)
To evaluate the qualities of the
rice varieties
(iii) To determine the starch content of the
different rice varieties
(iv) To
analysis the amylose and amylopection
contents of the rice varieties.