Comparative analysis on the major nutrient composition
of locally available four different varieties of rice (Oryza sativa) in Bangladesh
Srikanta Chowdhury1*, Md. T.
A. Chowdhury1, Md. Golam Kabir1,
Dwaipayan Sikdar1, Aninda
Kumar Nath2, Md. Zia Uddin2 and Dibyajyoti
Saha2
1Department of Biochemistry and Molecular Biology,
University of Chittagong, Bangladesh.
2Department of Pharmacy, BGC Trust University Bangladesh,
Chittagong.
ABSTRACT:
The aim of the present study was to obtain comparative data on chemical
compositions and nutritive values of four different varieties of rice. The results indicated that moisture, ash,
total soluble solid and crude fiber contents of the different varieties of rice
were in the ranges of 9.98-10.90%, 9.45-11.12%, 10.06-11.25% and 9.35-10.35%
respectively. The ranges in the values of total protein, water soluble protein,
dry matter, polysaccharide, total sugar, reducing and non-reducing sugar
compositions of rice were 12.45-14.06%, 3.20-4.71%, 89.10-90.02%,
10.95-12.25%, 4.35-4.96%, 1.15-1.45%, and 3.10-3.58% respectively. Vitamin B1
and Vitamin B2 contents of rice were found to be ranged from
2.98-3.81 and 0.61-0.86 mg/100 gm of rice respectively. Twelve amino acids were
detected in all of the four varieties of rice in the total form by paper
chromatography. Rice contained about 14.95-16.16% oil. Triglyceride, diglyceride, monoglyceride, and
non-glyceride were found to be varied from
91.76-93.08%, 1.51-2.30%, 1.45-1.96% and 3.63-5.24% respectively. Rice oils
contained mostly unsaturated fatty acid which was varied from 71.06-74.95%.
Total lipids were fractionated into lipid classes by silicic
acid column chromatography.
KEYWORDS: Rice, Chemical compositions, Nutritive
values, Chromatography, Fatty acids.
INTRODUCTION:
Rice (Oryza sativa) is
the main food for the people of Bangladesh and the most nutritious part of
paddy since it contains significant amount of protein, carbohydrate, vitamins
and minerals. It is also a good source of oil which cannot be used for edible
purposes as the oil becomes rancid on standing due to higher activity of enzyme
(David et al.,
1960). Rice has great nutritive value as it contains lipid, protein, and
vitamins. It also contains vitamin A and vitamin B and antisterility
vitamin E (Gopala Krishna et al., 1984). Rice has been the subject of much use of human food
with respect to its potentiality as a source of protein, mineral and vitamin
like wheat and soybean. Researches on plant proteins are currently attracting
much interest to the scientist because of their unique biological properties.
Rice may be considered to use as a supplementary sources of protein since it
contains about 10-16% of protein. Many varieties of rice are available in
Bangladesh, but their nutritional values are not fully known individually.
Therefore four new varieties of rice have selected for comparing their
nutritional composition in the present study.
MATERIALS AND METHODS:
Four different varieties of rice (BRRI-4, BR-34, Indian Pyjam and Dinajpuri Pyjam) were collected from different region of Bangladesh.
These samples were collected directly from the farmers in fresh condition.
Determination of moisture content: Moisture content of four different varieties
of rice was determined by the standard method of IUPAC (1979). 2-3 gm of rice was weighed in a porcelain
crucible which was previously cleaned, heated to 100°C, cooled and weighed. The
crucible with the sample was heated in an electrical oven for about six hours
at 100°C. It was then cooled in desiccators and weighed again. Percent of
moisture content (gm per 100 gm of rice)
Determination
of ash content: Ash content of rice was determined following the
method of AOAC (1980). 1-2 gm of rice was weighed in a porcelain crucible which
was previously cleaned, heated to about 100°C, cooled and weighed. The
crucible, with its content, was placed in a muffle furnace for four hours at
about 600°C. It was then cooled in desiccators and weighed. The crucible was
again heated in the muffle furnace for half an hour to ensure completion of ash
production. It is then cooled and weighed again. This was repeated till two
consecutive weights were the same and the ash was almost white in color.
Percent of ash content (gm per 100gm of rice)
Determination of total soluble solids: Total soluble solid (TSS)
content of rice was directly determined from the percentage scale (0-90%) of
Kyowa hand refractometer. A drop of rice solution was
placed on the prism of refractometer and percent of
TSS was obtained from direct reading.
Determination of dry matter: Dry matter content was calculated from the
data obtained for percentage of moisture content. Amount of dry matter in the
rice (gm per 100 gm of rice) =.
Determination
of crude fiber: Crude fiber
content of the different varieties of rice was determined by the method of AOAC
(1950). 3-5 gram of rice was taken and 200 ml of boiling 0.225 N H2SO4
was added. The mixture was boiled for 30 minutes and the volume was kept
constant by adding water. The mixture was then filtered and the residue was
washed with hot water to make it free from acid. 200 ml of boiling 1.25% NaOH was added. After boiling for 30 minutes the mixture
was filtered again. The residue was washed with hot water to make it free from
alkali, followed by washing with sonic ethanol and ether. It was then
transferred to a crucible, dried overnight at 80-100°C and weighed. The
crucible was then heated in a muffle furnace at 600°C for 3 hours, cooled and
weighed again. The difference in the weight represented the amount of crude
fiber.
Determination of total protein content: Protein content was determined by the
method of Micro-kjeldhal (Jayaraman,
J., 1981). The procedure includes digestion, collection of ammonia, and titremetric estimation of ammonia. The nitrogen content was
calculated using the formula: 1 ml of 0.01N H2SO4 ≡
140 Kg of nitrogen in NH3. Thus the amount of nitrogen in sample was
calculated from the volume of standard H2S04 used for
titration. The value was multiplied by 6.25 to give the approximate protein
content of the sample.
Determination
of water soluble protein: Water soluble protein content of rice was determined
following the method of Lowry (Lowry, O. H. et
al., 1951) using 0.01% BSA as the standard (Figure 1).
Figure 1: Standard curve of glucose for estimation of
water soluble proteins
Determination
of polysaccharide content: The polysaccharide content of rice was determined by
the Anthrone method (Jayaraman,
J., 1981). The absorbance of the blue-green solution was measured at 650 nm in
a colorimeter. The amount of polysaccharide present in the rice was calculated
from standard curve of glucose (Fig 2).
Determination of total sugar: Total sugar content of rice
was determined colorimetrically by the anthrone method as describe in Laboratory Manual in
Biochemistry (Jayaraman,J., 1981).
Determination of reducing sugar: Reducing sugar content of
rice was determined by dinitrosalicylic acid (DNS)
method (Miller, G.L., 1959).
Amount of reducing sugar (gm per 100 gm of rice) =.
Figure 2: Standard curve of
glucose for estimation of sugar and polysaccharide
Determination of non-reducing sugar: Non-reducing sugar was
calculated from the formula as reported (Ranaganna,
S. 1979). Percent of
non-reducing sugar = (percent of total sugar - percent of reducing sugar).
Determination
of B vitamins: Vitamin B1
(Thiamine): Vitamin-B1 content of rice was determined
following the method of Anon (Anonymous, 1965). Percentage of vitamin B1
(mg per 100 gm of fresh rice) =
Vitamin B2
(Riboflavin) content: Vitamin
B2 content of rice was determined by the method of anonymous (1965).
Identification
of amino acids in rice: Rice samples of the experimental varieties were
sieved (30 mesh) and sun dried for 5 hours. Total amino acids of rice samples
were determined by 2 D paper chromatography following the method as described
in Laboratory methods in Biochemistry (Jayaraman, J.,
1981; Block and Bolling, 1951).
Extraction
of oil from rice: Oil is the triglyceride portion of the rice which is
extracted by suitable solvent under the operating condition. Continuous soxhlet extraction (South combe;
1926) device was used for the extraction of oil. Rice was sun dried for 6 hours
to reduce the moisture content and then crushed well to almost powder form by a
hand crusher. 100 gm of powdered mass was then placed in the thimble of the
apparatus. The oil was then extracted with n-Hexane in the continuous soxhlet extraction apparatus. The extract was evaporated
under reduced pressure (rotary evaporator) to obtain oil.
RESULTS
AND DISCUSSION:
Moisture: Moisture content of different varieties of
rice was varied from 9.98 to 10.90% (Table 1). BR-34 variety contained the
highest percentage of moisture (10.90%) whereas Indian Pyjam
variety contained the lowest amount of moisture (10.17%).
Ash: The amount of ash content of different
varieties of rice was found to be ranged between 9.45 and 11.12%. BR-34 variety
contained the highest amount (11.12%) while Indian Pyjam
variety contained the lowest amount of ash (9.45%).
Total soluble solid (TSS): It appears that TSS content in the rice was
ranged from 10.06 to 11.25%. BRRI-4 variety contained the highest amount of TSS
(11.25%) whereas BR-34 variety contained the lowest amount of' TSS (10.06%).
Crude fiber: The crude fiber content of different
varieties of rice was found to be in the range of 9.18 and 10.35%. Among the
varieties tested the BRRI-4 variety contained the higher amount of crude fiber
followed by BR-34 and so on in decreasing order.
Total Protein: Protein content in different varieties of
rice was ranged from 12.45 to 14.06%. Of the varieties examined Indian Pyjam contained the highest and BR-34 variety contained the
lowest amount of protein. Krishnamuti and Sree Ramle (1982) suggested that
the protein content of rice varied depending upon the variety finding of
present results suggested that rice might be used as a potential source of
protein.
Water soluble protein: Water soluble protein content of different
varieties of rice was found to be ranged between 3.20 to 4.71%. Indian Pyjam variety contained the highest amount while Dinajpuri Pyjam variety contained
the lowest amount of water soluble protein.
Dry matter: The dry matter content of rice was ranged
from 89.10 to 90.02% indicating no such significant variation in dry matter
contents among the varieties.
Polysaccharide, Total Sugar,
Reducing Sugar and Non-reducing Sugar:
The amount of polysaccharide present in different
varieties of rice samples were varied from 10.95 to 12.25%. As shown in the
Table-2, the BRRI-4 variety contained the highest amount (12.25%) whereas
Indian Pyjam variety contained the lowest (10.95%)
amount of polysaccharide. Total sugar content of different varieties of rice
was ranged between 4.35 to 5.04%. Among the variety examined BRRI-4 contained
the highest amount (4.96%) while BR-34 variety contained the lowest amount of
total sugar (4.35%). Both reducing and non-reducing contents were found to be
varied between 1.15 -1.45% and 3.10-3.58%, respectively.
Table-1: Moisture, ash, total soluble solid and crude fiber contents
of different varieties of rice.
|
Name of variety |
Moisture (g %) |
Ash (g %) |
TSS (g %) |
Crude fiber (g %) |
Total protein (g%) |
Water soluble Protein (g %) |
Dry matter (g %) |
|
BRRI-4 |
10.17 ± 0.021 |
10.96 ± 0.025 |
11.25 ± 0.030 |
10.35 ± 0.016 |
13.33 ± 0.011 |
3.98 ± 0.012 |
89.83 ± 0.030 |
|
BR-34 |
10.90 ± 0.019 |
11.12 ± 0.020 |
10.06 ± 0.020 |
10.15 ± 0.013 |
12.45±0.016 |
3.25±0.013 |
89.10±0.031 |
|
Indian Pyjam |
9.98 ± 0.020 |
9.45 ± 0.038 |
10.39 ± 0.025 |
9.35 ± 0.016 |
14.06 ± 0.020 |
4.71 ± 0.018 |
90.02 ± 0.030 |
|
Dinajpuri Pyjam |
10.41 ± 0.016 |
10.25 ± 0.019 |
10.17 ± 0.020 |
9.45 ± 0.012 |
12.71 ± 0.016 |
3.20 ± 0.020 |
89.59 ± 0.030 |
Table-2:
Polysaccharide, total sugar, reducing sugar, non-reducing sugar and vitamin
contents of different varieties of rice.
|
Name of variety |
Polysaccharide (g
%) |
Total sugar (g %) |
Reducing Sugar (g
%) |
Non-reducing
Sugar (g %) |
Vitamin B1
(mg/100 g ) |
Vitamin B2
(mg/100 g ) |
|
BR-5 |
12.25±0.015 |
4.96±0.012 |
1.45±0.011 |
3.51 ±0.014 |
3.04±0.015 |
0.85±0.021 |
|
BR-10 |
11.35±0.011 |
4.35±0.011 |
1.25±0.011 |
3.10±0.021 |
3.25±0.020 |
0.76±0.032 |
|
IRRI-28 |
10.95 ± 0.019 |
4.85 ± 0.013 |
1.36 ± 0.014 |
3.49 ± 0.026 |
3.81±0.036 |
0.86±0.034 |
|
BRRI-39 |
11.06 ± 0.020 |
4.73 ± 0.015 |
1.15+0.015 |
3.58 ± 0.025 |
2.98±0.013 |
0.61±0.022 |
The table-2 shows the analytical values of vitamin B1
content of different varieties of rice. Vitamin-B1 content was
ranged from 2.98-3.81 mg percent. Indian Pyjam
variety contained the maximum percentage of vitamin-B1 followed by
BR-34. Vitamin B2 content was ranged between 0.61-0.0.86 mg percent.
Of the varieties examined Indian Pyjam variety
contained the highest amount while Dinajpuri Pyjam variety contained the lowest amount of vitamin B2.
Amino Acids:
Twelve amino acids such as alanine,
arginine, aspartic acid, glutamic
acid, glycine, histidine, leucine, lysine, phenylalanine, proline,
serine and tyrosine were detected by paper chromatography in all the varieties
of rice. As shown in the Table-3, BRRI-4 variety contained the highest amount
of alanine (0.896%) aspartic acid (0.998%) and lysine
(0.438%). Again, BR-34 Variety contained the highest amount of glycine (0.740%) and leucine
(0.521%). The highest value of arginine (0.642%), glutamic acid (1.425%), histidine
(0.419%), phenylalanine (0.678%), proline(0.705%)were
obtained in variety Indian Pyjam whereas Dinajpuri Pyjam variety contained
the highest amount of serine (0.639%).
Table-3: Some amino acid
compositions determined by paper chromatography of different varieties of rice
(Percentage in fresh rice)
|
Amino acid |
Rice variety |
|||
|
BRRI-4 |
BR-34 |
Indian Pyjam |
Dinajpuri
Pyjam |
|
|
Alanine |
0.896 |
0.730 |
0.874 |
0.703 |
|
Arginine |
0.436 |
0.519 |
0.642 |
0.529 |
|
Aspartic acid |
0.998 |
0.845 |
0.976 |
0.842 |
|
Glutamic acid |
1.301 |
0.976 |
1.425 |
0.897 |
|
Glycine |
0.610 |
0.740 |
0.415 |
0.437 |
|
Histidine |
0.205 |
0.316 |
0.419 |
0.217 |
|
Leucine |
0.412 |
0.521 |
0.317 |
0.254 |
|
Lysine |
0.438 |
0.243 |
0.419 |
0.295 |
|
Phenylalanine |
0.614 |
0.539 |
0.678 |
0.413 |
|
Proline |
0.531 |
0.610 |
0.705 |
0.546 |
|
Serine |
0.406 |
0.541 |
0.627 |
0.639 |
|
Tyrosine |
0.714 |
0.459 |
0.913 |
0.615 |
Analysis of rice oil:
The oil content of different varieties of rice were found to be ranged between 14.95 and
16.16% as shown in Table-4. BRRI-4 variety contained the highest amount
(16.16%) while Indian Pyjam variety contained the
lowest amount of oil (14.95%).
Table-4:
Oil content and physical characteristics such as specific gravity and
refractive index of different varieties of rice oil.
|
Name of variety |
Amount of oil (%) |
|
BRRI-4 |
15.38±0.011 |
|
BR-34 |
15.08± 0.012 |
|
Indian Pyjam |
14.95± 0.010 |
|
Dinajpuri Pyjam |
15.11± 0.013 |
CONCLUSION:
Many varieties of rice are available in Bangladesh.
Among them most widely cultivated varieties are BRRI-4, BR-34, Indian Pyjam and Dinajpuri Pyjam. These varieties are also distinguished by their
principal physical characteristics such as length, width and thickness of the
grain, color of the hull and tips, flavor and other properties. These varieties
are contributing to the generation of a huge quantity of rice bran as an
agricultural waste which could be utilized for the production of useful oil.
This study is important in providing an opportunity to improve the nutritional quality
of rice and for setting up nutritional and export regulations in Bangladesh.
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Received on 21.11.2011
Modified on 09.01.2012
Accepted on 15.02.2012
© A&V Publication all right reserved
Research J.
Science and Tech. 4(1): Jan.-Feb. 2012: 13-17