2.4.1  COOKING TIME    
2.4.4  WATER UPTAKE    

      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, purseglove 1972)
       Rice (oxyza sativa) is a staple food of billions of people and is consumed mostly as intact except hulls, bran and germ. It is  food that is very rich in carbohydrate and is also an important tropical cereal which also supplies a quarter of the entire calorie intake of the human race.  Rice is believed to have originated from south Asia and Africa.  Most cultivated varieties of rice are in diploid species oryza sativa and oryza glaberin.
         Rice is grown in all the ecological and dietary zones of Nigeria, with different varieties processing adaptation traits for each ecology (Sanni et al 2005).  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 ground rice with stew or soup.  Rice is cooked by washing and boiling in water which leads to loss of some nutrients.  The proximate composition of rice has been previously reported (Abulude 2004)
          Despite the fact that different varieties of rice are widely cultivated in Nigeria, for example, ‘Ofada’ and ‘Abakaliki’ rice , there is an up surge in the influx of foreign or imported rice varieties into the country.  A popular foreign and parboiled rice variety in Thailand, widely consumed and imported into Nigeria, is ‘Aroso’ rice
          Starch have been widely used as thickeners for many years.  The primary sources of starches are the corn, wheat, potato and tapioca.  Rice starch are the little known secret of the starch world comprising a very small percentage of the total starch usage. (Swany 1982)
          There are two types of starch in rice, amylose and amylopectin. Amylose 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. Long grain white vice has the most  amylase and the least amylopectin, so it tends to be the fluffiest more when cool, going in tightly together and forming crystals that melt when the rice is reheated Rice  that that is high in amylopectin is a has a lower glycemic index number (Bhattacharva 1997)
            Amylopectin is a highly branched molecule that makes the rice sticky when it’s released from the grain during cooking. Medium grain rice has more amylopectin making it a good candidate for visottos, salads and rice pudding, which are served cold. And short grain rice has even more amylopectin and little to no amylose, 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 far 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 mouthfeel. They have widely used as fat replacers in wide range of food product, waxy rice starches can be used at low level in food to create the sensation of richer and higher fat product.
The objectives of this work are to determine
(1)       Cooking properties of rice
(2)       Sensory evaluation on some rice varieties
(3)       The amount of starch on different variety of rice.

History of rice
            Starting in 2500BC, rice has been a source of food for people. Rice production originated in china, and was spread to countries such as Srilanka and India. It is believed that rice was bought to west Africa and Greece in 300BC, by Alexander the Great’s armies. In 800 AD. People in East Africa traded with people form India and Indonesia and were introduced to rice, it was a common belief in the middle Ages that rice fields were a breeding ground for malaria. People believed that mosquito easily layed their eggs in the water of the rice fields.
            Rice was introduced to Greece and neighboring Mediterranean (344-324B.C.E) and then gradually to Europe and Africa (IRR 1997) there have been debates about the introduction to Asia rice into Africa oryza sativa was believe to have been introduced to Africa primarily from malayoolynesia a few centuries B.C.E or form sri Lnaka and Indonesia. The other possibilities for the introduction of rice into Europe are form Persia, Central Asia, or directly form China. Later the Portuguese brought rice to Brazil and the Spanish introduced rice to Central and south America Oryza Sativa was introduced to Egypt form India and finally to west Africa by Portuguese spice traders between the 15th and 17th century (Grist 1986).
            Origin and diffusion of rice are still unsettled (Huke 1990) Asian cultivated rice originated in the region from south china to the changes ins south and south east Asia, including the river valleys and deltas of the Brahaneputra of northern India, the irrawaddy of Burma, the making of vietenam and the Yangtse of china based on the number of wide rice specie and evidence of rice glumes in the burnt day from the late Neolithic period (Ting, 1949) concluded that rice might have in south china and spread northwards (Capeland 1924) and some Japanese rice scientists asserted that rice might have originated from south or south east Asia, including India, china, Thailand and Indonesia.
            Thermolumine scene and carbon 14 test of the pottery shards with the imprints of rice grains in Thailand indicates that rice could be dated back to at least B.C.E (IRR, 1997). The second oldest pieces of archacological evidences for rice origin are from maharaga of India (6500-4500 B.C.E) and pentonshan of china (7150-6250 B.C.E) (Abro et al., 1999.
African varieties:     African rice (Oryza glaberrima) new rice for Africa, ofada rice.
Austrilian varieties:  Amaroo, kyeema, langi and opus e.t.c
Bangladeshi varieties: chinigura, kalijira, kataribhog, payam rice, e.t.c
Cambodian varieties:  neangkhon, bonla pdao, senkrob.
Canadian varieties:  wild rice e.t.c
Chinese varieties:  forbidden rice e.t.c
Indonesian varieties: peta, Rajelele (Semi-aromatic) Temang gung black rice.
Iranian Varieties:     Domsianh, Binam, Hasani, e.t.c
Italian varieties:       Arborio, ariete and Baldo.
            World wide there are more than 40,000 different varieties of rice, species name Oryza sativa. There are four major categories of rice world wide indica, japonica, aromatic and glutious. Improved varieties that have the following essential characteristics are, high yields, good grains quality and resistant to rice blast disease most improved varieties are also resistant and tolerant to drought, cool temperature, iron toxicity in the soil (Odomena, 2006).  

Nutritional composition of rice, rice, white, long-grain vegetable, raw nutritional value of per 100g (3.502).
1,527K, (365K CAL
Dietary fiber
Thiamine (vitamin b1)
0.070lmg (6%)
Ribo flavine (vitamine B2)
0.0149mg (1%)
Niacin (Vitamin B3)
1.62mg (11%)
Pantothenic acid (B5)
1.014mg (20%)
Vitamin B6
0.164mg (13g)
28mg (3%)
0.80mg (6%)
25mg (16%)
115mg (16%)
115mg (2%)
1.088mg (52%)
1.09mg (11%)
Source: Usda nutrient database

            Rice is a good source of protein and a staple food in many parts of the world, but it is not a complete protein. It does not contain all the essential amino acid in sufficient amounts for good health.
            Rice is rich in starch moderate in protein, poor in fat, iron and calcium provides about 350 kcal (1.47m) per 100g day weight (Wadswort 1993) Rice is a complete food, it does not contain some amount of thiamin, riboflavin and niacin but lacks in vitamin (A,D,C) The level of vitamin is considerably low in polished rice than in brown rice due to high content of b- complete vitamin in the bran and germ that are removed during milling.
Starch is one of the most important natural organic compound, abundant in nature. It is found in the roots or fruits (Duprat et al, 1980; Buleon et al., 1990). The most common sources of food starch are corn, potato, wheat, tapioca and rice (Woolfe, 1992; Henry and Westby, 1998). Developed countries (Canada, USA, Europe and Japan) have 77% of the global starch market (Sansavani and Verzoni, 1998).
            Starch is a polysaccharide (meaning “many sugars”) made up of glucose units linked together to form long chains. The number of glucose molecules joined in a single starch hundred thousand, depending on the type of starch. Starch is the storage form of energy for plants, just as glycogen is the storage form of energy for animal. Starch exists as granules varying in diameter from 2 to 130 microns. The size and shape of the granule is characteristic of the plant from which it came and serves as a way of identifying the source of a particular starch (Swamy 1982).
            Starch is predominantly composed of two polysaccharides macromolecules, amylose (20-30%) and amylopectin (70-80%). Amylose is mainly linear with very few branches, while amylopectin is highly branched. The organization of amylopectin and amylase is the basis for the semi-crystalline structure of the starch granule (Bell et al., 1998). The ratio of amylose to amylopectin is one of the key factors determining industrially important properties.
            Starch modification is the changing of starch so that it obtains the characteristics that deviate from the nature starch. The products are called derivatives. Chemically modified starches are starches that have been modified with chemicals.
-           amylose
-           amylopectin
            Amylose averages 20 to 30% of the total amount  of starch in most native starches. There are some starches, such as waxy starch, which contain only eamylppectin. Others may only contain amylose. Glucose residues united by a 1,4 linkage form the linear chan molecule of amylose. Amylose is the linear fraction and amylopectin is the branched  fraction. The is because the linear chains can orient parallel to each other, moving close enough together to bond. Probably due to the ease with which they can slop past each other in the cooked paste, they do not contribute significant to viscosity. The branched amylopectin molecule give viscosity to the cooked paste. This is partially due to the role it serves in maintaining the swollen granule. Different rice have different relative amounts of amylose and amylopectin. These different proportions of the two types of starch within the starch grains of the plant give each starch it’s characteristic properties in cooking and gel formation.
            Rice starch composes approximately 90% of  milled rice. It is made up of two major glucose polymers, amylose which is a slightly branched, primary long chain and amylopectin, which is highly branched. The amylose content of rice starch ranges form 0 to 30% (w/w) cooked rice texture and rice starch functional properties are reported to be primarily impacted by amylose content (Bhatta charya, soubhagy. Indudhara swamy 1982)
Because of its structure starch bears some special properties which make it a unique natural polymer. The following list contains the most important properties of starch, which are highly dependent on the origin and the chemical.
 Physical modification of the polymer
-           thickener
-           Rheology enhancer
-           Film former
-           Sticking – adhesive (cohesive
-           Water binding capacity
-           Water retention
-           Flocculent
-           Shear stability
      (Muhrbek 1987 )
Starch components and molecular weights of rice oryzenin
Oryzenin (protein medium – grainrice)

Medium - grainrice


Long grain rice

Long grain rice



Medium-grain rice

Medium-gran rice


Longer grain rice

Long grain rice

(sources J. Chrastil, 1990)
            Starch composition of milled rice largely determines the cooking and eating characteristics of rice. Starch consists of amylase and amylopectin. Amylase is a long, straight starch molecule that does not gelatinize during cooking long grain white rice has the most amylase and the least amylopectin. Amylopectin is a highly brached molvecue that makes the sticky when it’s released from the grain during cooking. Medium grain rice has more amylopectin.
            Rice can thus be generally categorized into
1.         Waxy (or glutinous) rice, which is mainly amylopectin and has an opaque endosperm. These high amylopectin starches endosperm. These high amylopetin starches are available with a range of viscosity and stability characteristics
2.         Non-waxy rice, which is mainly amylase and usually has a translucent endosperm.
            Volume expansion and water absorption of milled rice during cooking increases with increased amylase content. Cooked high-amylose rice is less tender, but drier and flakier (not sticky) than intermediate or low amylase rice, but becomes harder on cooling. After cooking, low amylase rice remain glossy, stocky and moist (Damion and Ben, 2006)
Amylose content (Effect of Cooking)
            This is considered one of the most important quality factors of rice since it is known that amylase content is a good index of water absorption and textural properties of rice. The texture of cooked rice and its gloss are principally determined by the amylase, amylopectin ratio of the starch. Increasing the amylase content improves the capacity of the starch granule to absorb water and expand in volume without collapsing because of the greater capacity of amylose to hydrogen bond or retrograde. Thus, the amylase content is an index of resistance to disintegration during cooking. It has been shown that an increase in amylose content improves the firmness of cooked parboiled rice, the correlation coefficient ® between amylase content and firmness being 0.62. amylase content of milled rice is determined by the colourmetric method is the starch-iodine blue test which is used for screening amylose content of sample with less than 30% amylase. The most widely used method involves digesting  100mg of rice flow with lml, 95% ethanol and 9ml of NaoH heating the sample for 10m in a boiling eater bath and diluting the gelatinized starch with distilled water, 5ml of the starch solution is pipettes into a 100ml volumetric flask lml of in acetic acid and  2ml of iodine solution added made up to volume and absorbance read at 620m. amylose content is determine by reference to a standard curve.
The amylase content of some Nigeria rice varieties has been shown to very between 19% and 28%. Various workers have shown that parboiling does not effect the amylase content of rice (Adeyimi 2006)
Amylose content affects rice cooking and eating quality
Amylase content
Low amylose
High amylose
-           100 amylose rice are moist, skicky, and glossy hen cooked
-           They spit and disintegrate when over cooked
-           High amylase rice cook dry and fluffy but become hard when cool
-           Intermediate amylose rice are fluffy when cooked and remain soft when cool(Andrew 2006)
            Cooking quality is one of the important aspects of food quality. However, nutrition’s a food material may be, it will not be accepted by the consume unless it satisfies specific culinary characteristic amylose dispersion is responsible for greater absorption and retention f water and thus the expansion of rice grain (Chungcharoen 1987).
Long Grain
            The category known as long grain contains milled rice that is approximately three times longer than it is wide. A conventional U.S long grain rice has an intermediate gelatinization temperature and from 19 to 23% apparent amylose content (Houston 1972).
            After cooking it is firm and fluffy, consumers in areas of the world such as North and South America, southern China, Europe, and the middle East often prefer this type of rice. California long grain rice generally has slightly highly apparent amylose content and lower gelatinization temperature compared to southern grown U.S long rice.
Medium Grain: The medium grain rice category describes milled rice that is from 2.1 to 2.5 times longer than it is wide U.S. medium grin rice after cooking is soft, moist and sticky in texture. This type of rice is in general preferred by people from Japan, Northern China and North and south Korea (Houston 1992) medium grain rice is generally lower in amylose content and has a lower gelatinization temperature compare to U.S conventional long grain
Short Grain:  Rice that is less then two times longer than it is wide classified as short grain. In general short grain rice has cooking quality, amylose content and gelatinization temperature similar to that of rice in the medium grain category. Because this type o rice is used for making sushi some call it sushi rice.
            Virtually all the rice produced in Nigeria is used for human consumption. The increase in consumption has been predicted to continue at a rate faster than the rate growth in population rice apart form being eaten as a while grain can be used in food industry in the processing of some products such as infant foods, break fast foods, snacks, rice flour and for production of alcoholic beverages such as beer and rice wine etc (Ihekoronye and Ngoddy 1985)
            Break fast food and baby foods” rice are pre-cooked, dried, flaked formed and expanded and toasted into ready to-eat break fast foods. The rice flour can be made into baby food since is absolutely gluten free. Some people are allergic to gluten and may turn rice based product (wade 1972).
Noodles: The resultant rice flour can equally be made into noodles,  a mixture of rice and egg being made into dough and expressed through holes. The noodle is improved by the use of local gums, okra gums and gum Arabic (NIFEST, 1999).
Beverages:  Various aleoholic beverages are manufactured From rice. Rice is also used in the brewing industry for the manufacture of beer and in the production of wine. (Yashizawa and Kishi 1985)
            Rice breeders considers rice quality as the most important factors after yield, that determine the accept ability and price of processed rice. The physio-chemical characteristics of rice determine it quality. The term quality refers to milling quality appearance and market acceptability, cooking eating qualities. Storage and nutritional quality. Rice quality changes continuous through the entire post-harvest system. Some of the changes are negative, but grain milling quality can also improve during storage (Bradley, 2007).

            Rice qualities are affected by many factors, which may vary according to the standard on which it will be sold (grist 1986). The degree of milling, percentage of damage kernel and percent of broken are all important factors.
            Milling degree: Milling degree is an important factor for quality. This depends on the size and shape, i.e on the variety, conditions under which it was grow, the degree of ripeness and amount of exposure. Milling removes the bran layer. Rice bran is about 20% oil and is subject to very aggressive enzyme activity.
Broken Rice: Broken rice get soft and mushy cooked from a nutrition standpoint, broken are the same as whole grain. But the texture is poor and broken tend to have more bran, which affect flavour (Liu et al., 1998).
Nature of Starch:  The nature of the starch affects texture and retro graduation properties of rice. The nature of rice starch differs depending on variety, growing area, and crop year. There are two different types of starch. Amylose is a long chained starch without a lot of branding and amylopectin is a shorter but much more highly branched chairs of element.
            The amylopectin/amylose ratio does not exist a very important factor.
Age of Rice:  Age creates changes in nature of starch. Rice gets harder with age as if the percentage of amylose is increasing. The rice gets former and less sticky most older rice losses moisture and so the cracking problem during cooking occurs if there is any brain on the surface of the rice due to loose milling, then rancidity problems causes poor flavour.
Moisture:  The moisture of the rice prior to cooking also affects texture. If the moisture is below 13% the quick involvement of water will cause cracking. The lower the moisture, the greater the cracking. Rice that cracks will have a poor cooking texture.
Cracking of Rice:  This is probably the biggest factor affecting the quality of cooked rice. The quick migration of moisture through rice causes cracking kernel. Quick changes in temperature can cause cracking. The cracking can occur in milling where milling temperature gets high or as a result of pressure applied in milling. Also cracking releases enzymes that affect flour.

            Different varieties of Rice (Oryzae Sativa) will be gotten from the Abakaliki rice mill. They will be packed and representative samples will be drawn from the bagged sample from distal, middle and proximal end using a sample probe. The sample will be analysed for starch content, amylose and amylopectin determination e.t.c.
Chemical Analysis
            The method described by Onwuka, (2005) will be use to determine the starch content of the sample.
Two point five grammes (2.5g) of the samples with 50ml cold water will be mixed. After allowing it to stand for one hour (1hr), 20ml concentrated HCL and 150ml distilled water will be added, then refluxed for 2hrs in a 250ml round bottomed flask, 5N NaoH will b used to cool and neutralize the mixture, distilled water will be used to make up the mixture of the mark.
            The glucose content will be determined using anthrone reagent.
            Series of glucose solution will be prepared such that 1ml contains 0.04-0.2mg, these solutions will be used to calibrate the glucose stand and curve.
Five milliliter (5ml) of anthrone reagent will be added to 1ml each of standard solution and a test sample in test tubes and then will be mixed properly.
            The tubes will be covered and boiled in water bath for 20 minutes for the odour to develop. The tubes will be cooled and the absorbance will be read/red at 620nm against a blank containing only 1ml of water and 5ml of anthrone reagent.
            The concentration of the test sample will be obtained by calculation involving the concentrations and dilutions made the mass of starch will be consequently obtained from the mass of glucose using the relation.
Mass of glucose x 0.9 = mass of starch
            The method of Juliano (1971) will be used. 0.1g of starch will be weighed into a test tube, 1ml of 95% ethanol and 9ml 1N NAOH will be added. The mouth of the tube covered with paraffin to mix content very well. 0.5ml of aligout will be used in the analysis. 0.1ml of acetic acid solution and 0.2ml of solution shall be added to make up 10ml of 9.2ml of distilled water and allowed for 20minutes for colour development and the % amylose shall be calculated as follows.
% amylose =%Amylose of standard x Absorbance of sample
Absorbance of standard
% Amylopectin = 100 - % Amylose
Protein Determination
            The crude protein in the sample were determined by the routine semi-micro Kje ideahl, procedure/technique as described by (AOAV 1984)
            0.5ml of each finely ground dried sample was weighed carefully into the kjeldahl digestion tubes to ensure that all sample materials got to the bottom of the tubes. To this were added lkjeidah catalyst table and 10ml of conc. H2Co4. these were set in the appropriate hole of the digestion Block heaters in a fume cupboard. The digestion was left on for 4 hours, after which a clear colourless solution was left in the tube. The digest was cooled and carefully transferred and made up into 100ms volumetric flask, it was distilled and filtered. Thoroughly rinsing the digestion tube with distilled  water and the flask was made up to mark with distilled water.
            The percentage nitrogen in this analysis was calculated using the formula.
% N     =          Titre value x Atomic mass of nitrogen x           Normality of HCL used X 4
The crude protein content is determined by multiplying percentage nitrogen by a constant factor of 6.25 i.e. % N x 6.25.
            The crude fat was determined using AOAC (1984) method. 1 gm of each dried sample was weighed into fat extraction thimble and pug lightly with cotton wool. The thimble was placed in the extractor and fitted with reflux condenser and a 250ml soxhlet flask which has been previously dried in the oven, cooled in the desiccater and weighed. The soxhlet flask is then filled to ¾ of its volume with petroleum ether ( 40 -600C) and the soxhlet flask. Extractor plus condenser set was placed on the heater. The heater was put on for six hour with constant running water form the tap for the ether to boil gently. The Ether is left to siphon over several times soy over at least 10-12 times until it short of siphoning. It is after this is noticed that any ether content of the Extractor is carefully drained into the ether stock bottle. The thumble containing sample is then removed and dried on a clock glass on the bench top. The extractor, flask and condenser is replaced and the distillation continues until the flask is practically dry. The flaks which now contains the fat or oil is detached its exterior cleaned and dried to a constant weight in the oven. If the initial weight of dry soxhlet flask is wo and the final weight of oven dried flask + oil (fat is w1, percentage is obtained by the formula:
       W1 – wo                         x          100
Wt of sample taken                            1
            The method described by Pearson. (1980) was used 2.og of the sample was gently weight into a clean curable. The sample was then gently heated in a murtle furnace at a temperature of 5500C for 3 hours all the organic matter was burn off leaving a white grey ash. The curable was placed in a desiccators to cool and weight was taken again. The percentage ash content was calculated.
% Ash w3  - w1
W2 - w2
W1       =          weight of empty curable
W2       =          weight of crucibles + sample
W3       =          weight of curable + Ash
            The moisture content was determined using AOAC (1984) method. The hot even method is used in the moisture content determinations. Petri dishes were washed and properly dried in he oven at 1000C for a period of 30 mins and cooled in a dessicator. The weight of the Petri dishes were determined by using the mettler weighing balance and labeled (w1) 5.g of the rice samples is carefully weighed into the dishes reweighed (w2) and put in the oven at 1000C for 3 hours after which it is removed cooled in the dissector and weighed again (w3)
            The percentage moisture is calculated form the weight loss of the sample
            Thus % moisture
Wt of dish + sample – wt of dish + sample after   x  100
                                                Wt of sample                                          1
Mathematically                    w2  -  w3                    x          100
                                                w2   -  w1                                   1

=          Difference in weight                        x          100
            Weight of sample                               1
=          Difference in weight                        x          100
            Weight of sample                                1
Physical Analysis
Sensory evaluation
Sensory evaluation of the cooked rice varieties was carried out of 20 untrained panelists in a special room prepared for the purpose (Ebuehi et al., 2004) they were instructed to taste the rice sample and to rinse their mouth after each sample taste. They were requested to express their feelings about the sample by scoring the following attributes: colour, odour, texture and taste. Sensory scores we based on a nine point hedonic scale, where 1 is dislike extremely and 9 is like extremely.

Cooking Properties
Cooking Time
            Using Anonymous (1997) method the cooking time was determined.
-           weight 5g of the sample into a beaker containing 25ML distilled water.
-           Note the time cooking stated and the time it ended.
Cooking time            =          time cooking -           time cooking
(minutes)                               ended                         Started
Gelatinization time and Gelatinization temperature
-           2og of the samples is weighed and poured into 100ml distilled water in a measuring cylinder after which it is transferred quantitatively into a beaker and heated in a heater that is set at its maximum range of 10.
            The heating continues until the sample gels and the temperature at which is started gelling was determined by a thermometer and recorded as the gelatinization temperature.
-           The difference between the time cooking started to the time at which gelatinization occurs is gelatinization time.
-           Water Absorbed During Cooking           the drained cooked sample is weighed using mettler balanced to determine the water absorbed during cooking. The difference in the weight of sample after cooking and that before cooking is taken as the water absorbed during cooking water absorbed 
=          weight of         -          weigh of
Cooked sample         fresh sample
Increased method
            The volume of cooked and raw rice was measured by water displacement method
-         weight 20g of raw rice into a graduated cylinder containing 100ml of distilled water and the change in volume noted.
-           20g of the cooked rice of which the water used in cooking have completely drained off is put into a cylinder containing distilled waters and change in volume noted. It is determined using the expression increase in = volume displaced after cooking – volume displaced         by raw sample.
            The method of FAO (1985) shall be used 10g of the milled raw rice shall be bulk together. It will be picking at random and a representative sample shall be selected. Length and width shall be measured using vernier caliper calibrating in millimeter (mm).
            The method of Singh et al (2004) shall be used. Length and width wise arrangement of milled rice shall be done and their cumulative measurements (1nmm) shall be taken. The value L/W shall be determined by dividing length width. A mean of 10 replication will be reported.
            The volume of cooked and raw rice shall be measured by water displacement method. 5g of raw rice shall be placed in a graduated cylinder containing 25ml of distilled water and the change in volume will be noted.
            The 5g of the cooked rice after which the water used in the cooking is completely drain off and the cooked sample shall be place in the cylinder containing the same 25ml distilled water and change in volume shall be measure.
            Volume expansion is determined using expression
Volume expansion = volume displaced after cooking – volume displaced by raw sample.  

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