Abstract. Samples of whole grain flour of five cereals (wheat, rye, barley, oats and buckwheat) were analysed for ash, starch, fat, cellulose and protein content. Coefficient of variation shows that within the same sample of whole grain flour variation of starch, protein, fat and ash content is relatively small, rarely exceeding 3%. The variability of the cellulose content is relatively high. The significance of the difference between chemical compositions of two independent samples of the same whole grain flour has been tested by Student&apos;s t-test. With the exception of protein content, the difference between two samples of buckwheat whole grain flou

A Fišteš

B Pajin

D Rakić

I Lončarević

T Došenović

Z Šereš

CiteSeerX

Acta Univ. Sapientiae, Alimentaria, 7 (2014) 45–53
Statistical analysis of the basic chemical
composition of whole grain flour of
different cereal grains
A. Fǐsteš
email: fistes@uns.ac.rs
T. Došenović
email: tatjanad@tf.uns.ac.rs
D. Rakić
email: drakic@tf.uns.ac.rs
B. Pajin
email: pajinb@tf.uns.ac.rs
Z. Šereš
email: zitas@tf.uns.ac.rs
Šoronja Simović
email: dragana@tf.uns.ac.rs
I. Lončarević
email: ivana.radujko@tf.uns.ac.rs
University of Novi Sad, Faculty of Technology,
Department of Carbohydrate Food Engineering
Bul. cara Lazara 1, 21000 Novi Sad, Serbia
Abstract. Samples of whole grain flour of five cereals (wheat, rye, bar-
ley, oats and buckwheat) were analysed for ash, starch, fat, cellulose and
protein content. Coefficient of variation shows that within the same sam-
ple of whole grain flour variation of starch, protein, fat and ash content is
relatively small, rarely exceeding 3%. The variability of the cellulose con-
tent is relatively high. The significance of the difference between chemical
compositions of two independent samples of the same whole grain flour
has been tested by Student’s t-test. With the exception of protein con-
tent, the difference between two samples of buckwheat whole grain flour
Keywords and phrases: cereals, whole grain flour, basic chemical composition, statistical
analysis.
45
46 A. Fǐsteš et al.
was significant. With the exception of wheat whole grain flour, for other
cereals, the difference in ash content between two samples was significant.
In all the other cases, there was no significant difference between two in-
dependent samples of the same whole grain flour. The significance of the
difference in chemical compositions between the whole grain flour from
different cereals has been tested by analysis of variance. Barley whole
grain flour shows significant difference in ash content, while wheat whole
grain flour significantly differs in starch content compared to other flour
samples. All investigated samples significantly differ in fat content. Oat
(higher content) and rye (lower content) whole grain flour significantly
differ to other samples considering the protein content.
1 Introduction
Cereals are the fruits of cultivated grasses, members of the Gramineae family
(Kent, 1975). Although a great number of cereal grains exist, eight are consid-
ered to be a principal cereal crops (cereals of commerce): wheat, corn, barley,
rye, oat, rice, sorghum and millet (Hoseney & Faubion, 1992). Buckwheat is
not a true cereal and belongs to the Polygonaceae family (Marshall & Pomer-
anz, 1982), but it is typically associated with the grain family due to similar
composition. Although different types of grain differ markedly in their proxi-
mate physical composition, all share the same basic anatomical structures: an
outer bran layer, a germ fraction and a starchy endosperm (Hoseny, 1998).
Each of the main parts of the grain has different structural characteristics and
chemical composition, and it is further subdivided into various layers (Kent,
1975). Depending on the type of grain, bran constitutes approximately 3-30%
of its dry weight. The outer bran layer includes the seed coat (pericarp and
testa), while the inner layers are composed of aleurone cells, positioned next
to the starchy endosperm. Some cereal grains (oat, rice and barley) also pos-
sess outer hulls, which are tightly bound to the bran layer. Both the amount
and composition of bran are highly variable across the different types of grain
(Hoseny, 1998). The bran layer is associated with a wealth of macro- and
micronutrients, including fibre, protein, B vitamins, minerals and flavonoids.
The germ makes up 4-17% of the dry weight of a whole grain. The germ is
a rich source of proteins, lipids, B vitamins and vitamin E. The starchy en-
dosperm makes up approximately 65-75% of the dry weight of a cereal grain,
and it is composed of starch, non-starch polysaccharides and small amounts
of protein and lipids (Marquart et al., 2002).
Statistical analysis of the basic chemical composition of whole grain flour. . . 47
Traditional flour milling process produces refined flour. During this pro-
cess, the bran and germ layers of grain are removed in order to stabilize the
raw material and to increase the keeping quality. Unfortunately, the type of
milling used for refined flour leads to the loss of certain nutrients (Nestle,
2006). If the bran, germ and endosperm components are retained during the
milling process, the resulting flour is classified as whole grain (Franz & Samp-
son, 2006). Whole grains contain all the essential parts and the same balance
of nutrients that are found in the original grain seed. Compared to refined
flour, whole grains are nutritionally superior; they are richer in dietary fibre,
protein, antioxidants, dietary minerals and vitamins. Diet rich in whole grain
foods has been associated with decreased risk of cardiovascular disease, dia-
betes, obesity and certain cancers (Jacobs et al., 1998; McKeown et al., 2002;
www.healthgrain.com). These are the reasons why the consumption of whole
grain flour attracts more and more attention.
Although cereal grains have many structural similarities, they do differ in
the relative proportion of their principal components and subsequently in the
chemical composition of whole grain flours. The aim of this study was to test
the significance of the difference in basic chemical compositions between the
whole grain flour from different cereals by analysis of variance (ANOVA).
2 Materials and method
Materials
Commercially available whole grain flours of five different cereals, namely
wheat, rye, barley, oat and buckwheat were used for the present study. Two
independent samples (2 × 1 kg) of each of the whole grain flour type were
analysed.
Methods
For each sample chemical characteristics, namely moisture, starch, cellulose,
fat, protein and ash, analyses were carried out as per standard methods. Mois-
ture content has been determined based on the weight loss suffered by the
sample when dried at a temperature of 130 to 133 ◦C (ICC standard method
No.110/1 ). Starch content has been determined according to Ewers polarimet-
ric method (ISO 10520 ), using the Elmer-Perkin polarimeter. Crude cellulose
content has been determined according to Kirschner-Ganakova‘s procedure
(Ćirić et al., 1975). Crude lipids were extracted from the samples in a Soxhlet
extractor with ether. The crude fat content was determined gravimetrically
48 A. Fǐsteš et al.
after oven-drying. The crude protein content was calculated by multiplying
the corresponding total nitrogen content, which was determined according to
the Kjeldahl method (ICC standard method No.105/2 ), by a factor of 6.25.
To determine the ash content, the samples were placed in a muffle furnace
at 900 ◦C for 2 hours, and weighed before and after (ICC standard method
No.104/1 ). The results are expressed as percentage by weight of sample, and
presented on a dry matter basis. Each analysis was carried out in triplicate
and mean values ± standard deviation reported.
Statistical analysis
The data were analysed by the following statistical procedures: coefficient of
variation, t-test and ANOVA (performed by STATISTICA 12). The means
were compared using the Tukey test at the 95% significance level.
3 Results and discussion
Representative values for the proximate composition of the investigated whole
grain flour samples are shown in Table 1. However, for any cereal, a wide range
of values for each chemical constituent can be encountered when a series of
samples is analysed. This is the reason why the figures given in Table 1 are
limited only to reveal the major differences between the investigated whole
grain flours.
The highest protein and fat (lipid) contents were registered in whole grain
oat flour. Compared with other cereals, oats are known to contain high amount
of protein and especially lipids. The protein content (16.91-17.46%) was within
the range (15-20%) as reported by Robbins et al. (1971) andMcMullen (1991).
The lipid content (6.41-6.49%) also was within the range (5-9%) reported
previously (Youngs, 1986; Saastamoinen et al., 1989). The highest ash and
cellulose contents were registered in whole grain barley flour. The mineral
and cellulose (fibre) contents are higher in barley compared to other cereals
as a consequence of the presence of hull. The hull (10% of the grain dry
weight) is undesirable for human consumption and it needs to be removed
before the covered grain can be used as a raw material for flour production.
After removing the hull, the differences in mineral and cellulose contents are
much reduced. However, since the parts of the outer layers of the kernel are
removed, some may not regard this flour as a whole grain (Andersson & Aman,
2008). As expected, the highest starch content was registered in whole grain
wheat flour.
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Table 1: Ash, starch, cellulose, fat and protein content in the samples of whole grain flour
Sample Ash CV Starch CV Cellulose CV Fat CV Protein CV
(%)dm (%) (%)dm (%) (%)dm (%) (%)dm (%) (%)dm (%)
Barley 1 2.52 ± 0.007 0.27 60.98 ± 1.404 2.30 3.25 ± 0.382 11.74 1.87 ± 0.038 2.02 15.25 ± 0.328 2.15
Barley 2 2.42 ± 0.017 0.68 59.50 ± 0.241 0.41 2.85 ± 0.126 4.44 1.82 ± 0.044 2.42 14.53 ± 0.067 0.46
Oat 1 1.69 ± 0.017 0.56 62.69 ± 1.436 2.29 1.33 ± 0.196 14.69 6.41 ± 0.306 4.77 17.46 ± 0.769 4.40
Oat 2 2.01 ± 0.009 0.97 63.57 ± 0.931 1.46 1.40 ± 0.078 5.56 6.49 ± 0.162 2.50 16.91 ± 0.010 0.06
Wheat 1 1.57 ± 0.004 0.26 69.31 ± 2.100 3.03 2.24 ± 0.096 4.28 1.48 ± 0.032 2.14 14.78 ± 0.092 0.62
Wheat 21.57 ± 0.027 1.72 69.82 ± 2.010 2.87 2.01 ± 0.437 21.67 1.53 ± 0.012 0.77 14.98 ± 0.448 3.00
Buckwheat 1 2.00 ± 0.024 1.21 60.35 ± 0.457 0.76 2.87 ± 0.027 0.93 2.51 ± 0.060 2.40 15.70 ± 0.329 2.10
Buckwheat 2 1.60 ± 0.146 9.14 62.97 ± 0.893 1.42 2.59 ± 0.121 4.66 2.38 ± 0.053 2.25 15.15 ± 0.194 1.28
Rye 1 1.52 ± 0.007 0.46 62.23 ± 0.849 1.36 1.71 ± 0.097 5.66 1.17 ± 0.124 10.60 13.74 ± 0.355 2.58
Rye 2 1.66 ± 0.036 2.19 62.44 ± 0.627 1.00 1.85 ± 0.045 2.42 1.23 ± 0.087 7.03 13.98 ± 0.146 1.04
Values are mean ± standard deviation of three independent determinations; dm – dry matter basis CV –
coefficient of variation
50 A. Fǐsteš et al.
Generally speaking, the values presented in Table 1 are within the range of
values previously reported for the chemical composition of wheat (Kent, 1975),
buckwheat (Marshall & Pomeranz, 1982; Steadman et al., 2001), rye (Vinkx
& Delcour, 1996), oat (Kaukovirta-Norja & Lehtinen, 2008) and barley (An-
dersson & Aman, 2008).
The statistical analysis was performed in three steps. In the first step, the
coefficient of variation showed that within the same sample of each of the
investigated whole grain flour the variation of starch, protein, fat and ash
content is relatively small, rarely exceeding 3%, and in lot of the cases even
below 1% (Table 1 ). Ash content in the Buckwheat 2 sample and the fat
content in both of the rye samples can be considered an exception from this
general conclusion. On the contrary, the variability of the cellulose content
was relatively high (up to 21.67%).
In the second step, the significance of the difference between the chemical
compositions of two independent samples of the same whole grain flour was
tested using the Student’s t-test. With the exception of protein content, the
difference was significant between the two samples of buckwheat whole grain
flour. With the exception of wheat whole grain flour, for other cereals, the
difference in ash content between the two samples was significant. In all the
other cases, there was no significant difference between two independent sam-
ples of the same whole grain flour. In the third step, the significance of the
difference between the chemical compositions of the whole grain flour from
different cereal grains was tested by the ANOVA (Table 2 ).
Table 2: The significance of the difference between the chemical composition
of whole grain flour samples tested by ANOVA
Sample Cellulose Ash Protein Starch Fat
(%)dm (%)dm (%)dm (%)dm (%)dm
Barley 3.03 a 2.47 a 14.89 b 60.24 c 1.85 a
Oat 1.37 c 1.85 b 17.19 a 63.13 b 6.45 b
Buckwheat 2.73 a 1.80 bc 15.43 b 61.66 bc 2.44 c
Rye 1.78 b 1.59 c 13.87 c 62.34 bc 1.20 d
Wheat 2.13 b 1.57 c 14.88 b 69.57 a 1.50 e
Values are the means of six independent determinations; dm – dry matter
basis. Means with the same letter do not differ significantly.
Statistical analysis of the basic chemical composition of whole grain flour. . . 51
ANOVA showed that, in terms of cellulose content, there was no statistically
significant difference between barley and buckwheat flour or between wheat
and rye flour, while the oat flour is significantly different from all other types
of whole grain flours. By ash content, barley flour is allocated in a separate
group. A relative closeness exists between oat and buckwheat flour, while at
the same time the buckwheat flour is in the same group with wheat and rye
flour. Considering the protein content, oat flour (higher content) and rye flour
(lower content) significantly differ to other flour samples. Considering the
starch content, the investigated flours were classed into three groups. Wheat
flour is in a separate group. Barley and oat flour are different from each other;
however, they are not significantly different from buckwheat and rye flour. All
investigated whole grain flour samples significantly differ in fat content.
Acknowledgements
This work was done within the project “Cookies and crackers with functional
characteristics aimed for consumers with special diatery needs” financed by
the Provincial Secretariat for Science and Technological Development of the
Government of Autonomous Province of Vojvodina, Republic of Serbia.
References
[1] A. A. H. Andersson, & P. Aman, Functional barley products. In: Tech-
nology of functional cereal products. B. R. Hamaker (ed.), Woodhead
Publishing Limited, CRC Press, Cambridge (2008) 261–280.
[2] D. Ćirić, B. Vujičić, Ž. Bardić, Handbook for quality control of raw ma-
terials and fruit and vegetable products. Faculty of Technology, Novi Sad
(1975) 227.
[3] M. Franz, & L. Sampson, Challenges in developing a whole grain
database: Definitions, methods and quantification. J. Food Compos.
Anal., 19. (2006) S38–S44.
[4] R. C. Hoseney, & J. M. Faubion, Physical properties of cereal grains. In:
Storage of cereal grains and their products. D. B. Sauer (ed.), American
Association of Cereal Chemists, Inc., St. Paul, Minnesota (1992) 1–38.
[5] C. A. Hoseny, Principles of cereal technology. American Association of
Cereal Chemists, Inc., St. Paul, Minnesota (1998).
52 A. Fǐsteš et al.
[6] ICC Standard Method No.110/1, Determination of moisture content of
cereals and cereal products (Practical Method). International Association
for Cereal Science and Technology, Vienna (1976).
[7] ICC Standard Method No.104/1, Determination of ash in cereals and
cereal products. International Association for Cereal Science and Tech-
nology, Vienna (1990).
[8] ICC Standard Method No. 105/2, Determination of crude protein in ce-
reals and cereal products for food and for feed. International Association
for Cereal Science and Technology, Vienna (1994).
[9] ISO 10520, Native starch – Determination of starch content – Ewers po-
larimetric method (1997).
[10] D. R. Jacobs Jr., L. Marquart, L. H. Kushi, Whole-grain intake and
cancer: an expanded review and meta-analysis. Nutr. Cancer, 30. (1998)
85–96.
[11] A. Kaukovirta-Norja, P. Lehtinen, Traditional and modern oat-based
foods. In: Technology of functional cereal products. B. R. Hamaker (ed.),
Woodhead Publishing Limited, CRC Press, Cambridge (2008) 215–232.
[12] N. L. Kent, Technology of cereals. Pergamon Press, Oxford (1975).
[13] H. G. Marshall, Y. Pomeranz, Buckwheat: Description, breeding, pro-
duction, and utilization. In: Advances in cereal science and technology.
Y. Pomeranz (Ed.), American Association of Cereal Chemists, Inc., St.
Paul, Minnesota (1982) 157–210.
[14] L. Marquart, J. L. Slavin, R. G. Fulcher, Whole-grain foods in health and
disease. American Association of Cereal Chemists Inc., St. Paul, Min-
nesota (2002).
[15] N. M. McKeown, J. B. Meigs, S. M. Liu, P. W. F. Wilson, P. F. Jacques,
Whole-grain intake is favorably associated with metabolic risk factors for
type 2 diabetes and cardiovascular disease in the Framingham Offspring
Study. Am. J. Clin. Nutr., 76. 2. (2002) 390–398.
[16] S. D. McMullen, Oats. In: Handbook of Cereal Science and Technology.
K. J. Lorenz, K. Kulp (eds.), Marcel Decker Inc., New York (1991) 199–
232.
Statistical analysis of the basic chemical composition of whole grain flour. . . 53
[17] Nestle: Corporate Wellness Unit, Food and Nutrition Communication,
(2006).
[18] G. S. Robbins, Y. Pomeranz, L. W. Briggle, Amino acid composition of
oat groats. J. Agr. Food Chem., 19. (1971) 536–539.
[19] M. Saastamoinen, J. Kumpulainen, S. Nummela, Genetic and environ-
mental variation of oil content and fatty acids composition of oats. Cereal
Chem., 66. (1989) 296–300.
[20] K. J. Steadman, M. S. Burgoon, B. A. Lewis, S. E. Edwardson, R. L.
Obendorf, Buckwheat seed milling fractions: description, macronutrient
composition and dietary fibre. J. Cereal Sci., 33. (2001) 271–278.
[21] C. J. A. Vinkx, & J. A. Delcour, Rye (Secale cereale L) arabinoxylans: A
critical review. J. Cereal Sci., 24. (1994) 1–14.
[22] www.healthgrain.com
[23] V. L. Youngs, Oat lipids and lipid-related enzymes. In: Oats: Chemistry
and Technology. F. H. Webster (ed.), American Association of Cereal
Chemists, Inc., St. Paul, Minnesota (1986) 205–226.


Statistical analysis of the basic chemical composition of whole grain flour of different cereal grains

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Statistical analysis of the basic chemical composition of whole grain flour of different cereal grains

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