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▼ Journal of Research (Science), Bahauddin Zakariya University, Multan, Pakistan.
Vol.12, No.2, December 2001, pp. 171-179 ISSN 1021-1012
171 ▼J. res. Sci., 2001, 12(2), 171-179
SUITABILITY OF WHEAT VARIETIES/LINES FOR THE PRODUCTION
OF LEAVENED FLAT BREAD (NAAN)
Zubair Farooq
1
, Salim-ur-Rehman
1
, Masood Sadiq Butt
1
and Muhammad
Qamar Bilal
2
1
Department of Food Technology, University of Agriculture, Faisalabad.
2
Department of Livestock Management, Univ. of Agriculture, Faisalabad.
Abstract: Wheat is the staple food for the people of Pakistan. Its various
varieties/lines vary in their characteristics, which ultimately affect the quality of
the end product. The physical, chemical, rheological and flour characteristics of
the wheat varieties/lines explored various technological aspects of studies. On
the basis of the information got out of this study, it was found that wheat variety
LU-26 was ranked best by a panel of judges for the production of an improved
quality textured naan.
Keywords: Leavened flat bread,
Triticum aestivum
, physical, chemical,
rheological and flour characteristics
INTRODUCTION
Wheat (Triticum aestivum) is a major source of dietary energy and protein
for people whose daily diet is composed of cereal products. It is a staple
food, consumed world wide in the form of bread, biscuits etc. It is the
predominant cereal produced and eaten in Pakistan. It is the main staple
diet of the people of Pakistan [Economic survey 2000-2001]. It contributes
68-75% of the total food intake in the daily diet and provides 75% of the
total protein requirements [Aslam et al. 1982]. In Pakistan, dietary pattern
varies widely from one region to another but tends to weigh largely in
favour of cereals (wheat, rice etc.), pulses and meat. Large quantity of
wheat is milled into atta (a high-extraction flour), which is used for the
production of flat breads, especially chapaties and Naans.
Wheat quality can be improved if both genetic as well as biochemical
composition influencing technological properties are known. Both protein
quantity and quality are considered important in estimating the potential of
flour for its end use quality. The rheological characteristics of flour vary
between varieties [Wrigley 1993, 1994]. A review of available information
indicates some inadequacy in quality of the diet of the average Pakistani
particularly with respect to protein, vitamins and minerals, and serious
nutritional problems for the most vulnerable sector of the population
[Anonymous 1972].
In Pakistan, the most commonly consumed least expensive products are
chapaties and rotis, using almost 80% of the total wheat production.
These are the primary, and cheapest, source of protein and calories in
the diet [Anjum et al. 1991]. In Punjab and Sindh provinces chapatti and
roti doughs are unleavened while in Baluchistan and Frontier provinces
fermented roties are prepared.
Among these foods, naan has better digestibility and greater storage life.
Zubair Farooq, Salim-ur-Rehman, Masood Sadiq Butt and M. Qamar Bilal
172
It is mostly consumed at breakfast, while it is also available at luncheon
and dinner with specific dishes. Old people are the special age group who
may prefer to eat naan in their meals due to softness and better
digestibility. This research proposal was planned in order to provide better
nourishment to the specific group of people consuming naan. For this
purpose, physico-chemical, rheological and sensory analysis of wheat
varieties/lines was conducted.
MATERIALS AND METHODS
PROCUREMENT OF RAW MATERIALS
Wheat varieties LU – 26, LU – 31 and lines 4072, 4770, 4943, 5039 and
6500 were taken from the department of Plant Breeding and Genetics,
University of Agriculture, Faisalabad.
PHYSICAL CHARACTERISTICS OF WHEAT
The grains of each wheat variety and line were tested for thousand kernal
weight and weight per unit volume according to the standard procedure
[AACC 1983].
MILLING OF WHEAT
After tempering, wheat samples were milled using Quadrumate Senior
Mill following the standard method [AACC 1983]. As a result, four
products were obtained namely, reduction flour, break flour, bran and
shorts. Reduction and break flour were mixed to obtain straight grade
flour in order to perform further tests.
GENERAL CHARACTERISTICS OF STRAIGHT GRADE FLOUR
The flour obtained from the wheat varieties/lines was subjected to the
study of flour characteristics by determining particle size index, damaged
starch, SDS-sedimentatioin and pelshenke values, following the standard
methods [AACC 1983].
CHEMICAL ANALYSIS OF STRAIGHT GRADE FLOLUR
The wheat varieties/lines were analyzed for moisture content, ash, crude
fat, crude protein, crude fiber and nitrogen free extract (NFE) according to
their respective methods [AACC 1983].
RHEOLOGICAL CHARACTERISTICS OF STRAIGHT GRADE FLOUR
Rheological characteristics of wheat flours were determined by
performing the following studies.
Amylographic Studies
Diastatic activity of each sample was determined with Brabender
Amylograph [AACC 1983].
SUITABILITY OF WHEAT FOR PRODUCTION OF LEAVENED FLAT BREAD
173
Farinographic Studies
The straight grade flour samples of each wheat variety/line were run
through Brabender Farinograph equipped with a bowl of 50 g capacity.
The dough behaviour for water absorption, arrival time, dough
development, dough stability, dough resistance, tolerance index and
softening of the dough was determined according to the standard
procedure [AACC 1983].
PREPARATION OF LEAVENED FLAT BREAD (NAAN)
The production of traditional plain naan was based on natural
fermentation and naan dough disc was baked in a tanoor (mud oven) by
following the local method.
SENSORY EVALUATION
The naans were evaluated for texture by the standard method [Kulp et al.
1983].
STATISTICAL ANALYSIS
The data obtained was statistically analyzed using analysis of variance
technique [Minitab 1991, Snedecor et al. 1991].
RESULTS AND DISCUSSSION
PHYSICAL CHARACTERISTICS OF WHEAT VARIETIES/LINES
Table 1 represents mean values of thousand kernal weight and test
weight of the wheat varieties/lines. Thousand kernal weight varied
between 44g and 37g for line 5039 and variety LU-31 respectively. For
test weight Line 5039 showed maximum weight (85 kg/hl) followed by the
variety LU-26 (82kg/hl). The analysis of variance (Table 2) shows that the
results for thousand kernal weight were highly significant (P<0.01) and for
test weight significant (P<0.05).
Thousand kernal weight and size are not genetically controlled only but
also affected by growing conditions [William 1986]. In the present studies,
differences in the thousand kernal weight are attributed to the differences
in the genetic make up of the wheat varieties/Lines.
GENERAL CHARACTERISTICS OF STRAIGHT GRADE FLOUR
Particle Size Index
Mean values for particle size are given in Table 3. Maximum value was
observed as 22.2% in the case of variety LU-26 followed by 21.7% in
case of line 4943. Analysis of variance (Table 2) shows that the values for
particle size were non-significant among all the wheat varieties/lines
(P>0.05). These results are in conformity with previous findings [Ken et al.
1991].
Zubair Farooq, Salim-ur-Rehman, Masood Sadiq Butt and M. Qamar Bilal
174
Table 1: Comparison of means for physical characteristics of wheat varieties/lines.
Characteristics
Variety
LU-26
Variety
LU-31
Line
4072
Line
4770
Line
4943
Line
5039
Line
6500
Thousand kernal weight (%) 43.70a 37.11c 40.71b 38.76bc 39.24bc 44.38a 40.84b
Test weight (%) 82.00ab 78.00b 81.00b 79.00b 80.00b 85.00a 81.00b
Means with the same letter are not significantly different.
Table 2: Analysis of variance for various characteristics of wheat varieties/lines.
d.f = 6
Table 3: Comparison of means for general characteristics of straight grade flour of wheat
varieties/lines.
Characteristics
Variety
LU-26
Variety
LU-31
Line
4072
Line
4770
Line
4943
Line
5039
Line
6500
Particle size index (%) 22.20a 20.80a 17.20c 20.10ab 21.70a 17.70bc 19.40abc
Damaged starch (%) 10.00a 8.45b 7.00c 8.65b 9.75a 7.15c 7.77bc
SDS-sedimentation (ml) 21.00a 19.00b 18.00bc 17.00c 17.50bc 17.50bc 17.00c
Pelshenke value (min) 187.00a 180.00ab 165.00d 179.00ab 168.00cd 176.00bc 168.00cd
Means with the same letter are not significantly different.
Damaged starch
Mean values for this parameter of study are given in Table 3. Maximum
value for damaged starch was observed as 10.5% in thecase of variety
LU-26 followed by 9.75% in case of line 4943. In an earlier study the
damaged starch of the wheat cultivars ranged from 6.0 to 9.0% for
optimal bread quality [Ken etal. 1991]. Analysis of variance (Table-6)
Characteristics MS F P
Thousand kernal weight 20.67 4.97 0.006
Test weight 15.43 2.92 0.046
Moisture 0.10254 55.64 0.000
Ash 0.00364 8.79 0.000
Protein 2.48079 1908.30 0.000
Fat 0.00829 4.50 0.010
Fibre 0.00364 3.27 0.032
NFE 2.30284 249.15 0.000
Particle size index 10.88 1.38 0.288
Damaged starch 5.093 7.55 0.001
SDS-Sedimentation 6.18 7.43 0.001
Pelshenke value 191.7 9.19 0.000
Amylographic value 01200.00 1408.40 0.000
Water absorption 5.264 2058.66 0.000
Arrival time 0.152 0.35 0.900
Dough development 0.964 12.00 0.000
Resistance to dough 106.75 23.93 0.000
Dough stability 101.817 313.86 0.000
Softening of dough 600.00 6.22 0.002
Tolerance index 871.00 5.55 0.004
Texture 8.032 12.2222 0.000
SUITABILITY OF WHEAT FOR PRODUCTION OF LEAVENED FLAT BREAD
175
shows that the values for damaged starch were highly significant (P<0.01)
among all the wheat varieties/lines.
SDS-Sedimentation Test
Mean values for SDS-sedimentation are given in Table 3. The maximum
value of SDS-sedimentation was observed as 21 ml for variety LU-26 and
the minimum was 17.00 ml for line 6500. The values for SDS-
sedimentation test for all the wheat varieties/lines were highly significant
(P<0.01) as shown by Analysis of variance (Table 2). These results were
in range with previous findings [Corbellini et al. 1999]. They also stated
that the differences in SDS-sedimentation values due to differences in
locations are reflected by the variations in total protein content.
Pelshenke Test
Table 3 depicts mean values for this parameter. The maximum value of
Pelshenke was observed as 187 minutes for variety LU-26 and the
minimum was 165 minutes for line 4072. In a study [Branlard and
Dardevet 1985] the Pelshenke value was found as 155. So, the results of
the present study are not far off from that study. The values for Pelshenke
test for all the wheat varieties/lines were highly significant (P<0.01) as
shown by Analysis of variance (Table 2).
CHEMICAL ANALYSIS OF STRAIGHT GRADE FLOUR
Mean values for chemical analysis of the straight grade flour are shown in
Table 4. The maximum moisture content was observed in the wheat
sample Line 4943 that was 12.57% followed by Line 4770 as 12.53%.
The maximum ash content was observed in Line 4770 that was 0.60%
while the lowest content was found in Line-6500 as 0.50%. The average
protein content in all wheat varieties ranged from 12.03 to 10.00% for the
variety LU-26 and Line 4072 respectively.
Table 4: Comparison of means for chemical analysis of straight grade flour of wheat varieties/lines.
Characteristics Variety
LU-26
Variety
LU-31
Line
4072
Line
4770
Line
4943
Line
5039
Line
6500
Moisture (%) 12.50a 12.05d 12.40b 12.53a 12.57a 12.30c 12.25c
Ash (%) 0.58ab 0.56bc 0.55bcd 0.60a 0.53cde 0.52de 0.50e
Protein (%) 12.03a 12.00a 10.00d 10.12c 11.86b 11.84b 11.85b
Fat (%) 1.30bcd 1.40a 1.33abcd 1.35abc 1.37ab 1.25d 1.28cd
Fibre (%) 0.38ab 0.36abc 0.35abcd 0.40a 0.33bcd 0.32cd 0.30d
NFE (%) 85.71d 85.68d 87.77a 87.53b 85.91c 86.07c 86.07c
Means with the same letter are not significantly different.
The maximum fat content was observed as 1.40% in variety LU-31 and
the minimum was found as 1.25% in Line 5039. The maximum fibre
content was of Line 4770 that was 0.40% followed by variety LU-26 as
0.38%. The maximum value of NFE was 87.77 and minimum as 85.68
that of Line 4072 and variety LU-31 respectively. The range of protein
Zubair Farooq, Salim-ur-Rehman, Masood Sadiq Butt and M. Qamar Bilal
176
content of flour samples varies from 2 to 12.7% and the range of ash
content from 0.35 to 0.42% [Ken et al. 1991]. Chemical analysis of
straight grade flours of wheat varieties/lines showed highly significant
(P<0.01) results as shown in the analysis of variance Table 2.
RHEOLOGICAL CHARACTERISTICS OF STRAIGHT GRADE FLOUR
Amylographic Studies
Mean amylographic values are given in Table 5. Maximum value of
Brabander amylograph was observed in case of wheat variety LU-26 that
was 860 B.U, followed by line 6500 as 610 B.U. Analysis of variance
(Table 2) shows that the results of amylographic characteristics of all the
wheat varieties/lines were highly significant (P<0.01). In the present
study, differences in the peaks of the flours of different wheat varieties/
lines were due to differences in the amylase activity. The peak viscosity of
whole wheat flour is affected by wheat variety and nature [Siddique 1989].
Table 5: Comparison of means for rheological characteristics of straight grade flour of wheat
varieties/lines.
Characteristics
Variety
LU-26
Variety
LU-31
Line
4072
Line
4770
Line
4943
Line
5039
Line
6500
Amylographic value
(B.U)
860.00a 530.00d 0.00e 560.00c 600.00b 550.00cd 610.00b
Water absorption
(%)
55.30e 58.00a 57.30b 56.20d 54.80f 56.60c 54.40g
Arrival time
(minutes)
2.00a 1.75a 1.50a 1.50a 1.50a 1.75a 2.00a
Dough
development(min)
2.50b 3.75a 2.25b 2.00b 2.25b 2.50b 2.5b
Resistance to dough
(min)
19.75a 11.00c 10.45c 15.00b 4.00d 5.50d 4.00d
Dough stability
(Minutes)
17.25a 7.25c 8.20c 13.00b 1.75de 3.00d 1.50e
Softening of dough
(B.U)
40.00b 50.00b 80.00a 40.00b 50.00b 50.00b 40.00b
Tolerance index
(B.U)
40.00bc 40.00bc 30.00c 20.00c 60.00ab 40.00bc 70.00a
Farinographic Studies
Second parameter of rheological studies was farinograph. Table 5 shows
mean values of farinographic characteristics. Water absorption is
considered to be an important characteristic of wheat and composite flour
[Sollars and Rubenthaler 1975]. It ranged from 54.40 to 58.00% for wheat
line 6500 and variety LU-31. In the present study, the results of water
absorption are very close to the results of earlier researcher [Borghi et al.
1996] in which water absorption ranged from 53 to 60% and was
positively correlated with protein content (r = 0.67**).
Variation in the arrival time of different wheat varieties/lines reflects
differences in the rheological behaviour of the wheat varieties/lines.
Maximum arrival time was observed in wheat variety LU-26 and line 6500
(2 minutes).
SUITABILITY OF WHEAT FOR PRODUCTION OF LEAVENED FLAT BREAD
177
The dough development time also varied among all the wheat
varieties/lines and the results were in line with the previous findings
[Lukow and Bushuk 1984]. It ranged from 2.00 to 3.75 minutes for line
4770 and variety LU-31 respectively. There exists a range of dough
development time for hexaploid wheats from <90 seconds to 240 seconds
[Corbellini 1999]. The results of the present study were also close to
those findings. Developed doughs have higher complex moduli than the
undeveloped doughs.
As far the time for resistance of the dough was concerned, the longer the
time the stronger the flour. The resistance of various doughs in the
present study depicted the same situation. It varied among all the wheat
varieties/lines showing a range from 4.00 to 19.75 minutes for line 6500,
4943 and variety LU-26.
Maximum dough stability (17.25 minutes) was observed in case of variety
LU- 26 and minimum (1.50 minutes) for line 6500. In an earlier study
dough stability of whole-wheat flour was found as 4.5 minutes [Siddique
1989]. The dough stabilities in the present study were approximately in
range with that finding.
The values of the softening of the dough also differed for all the wheat
varieties/lines. According to a study by Corbellini et al. [1999], the degree
of softening was 50 B.U. that is very close to the results of the present
study in which there existed a range from 40.00 to 80.00 B.U for lines
4770, 6500, variety LU-26 and line 4072 respectively.
In general, flours that have good tolerance to mixing have low tolerance
index and the higher the tolerance index value, the weaker the flour. In
the present study, wheat line 6500 had maximum (70.00 B.U) tolerance
index and line 4770 minimum (20.00 B.U). The results of the present
study were similar to the result of Ciacco and D’Appolonia [1982] that was
40 B.U for sound wheat flour. Similarly, this value for Neepawa sound
wheat flour was found as 50 B.U [Lukow and Bushuk 1984]. Analysis of
variance (Table 2) showed highly significant (P<0.01) results for all the
parameters of farinographic characteristics.
PRODUCTION OF LEAVENED FLAT BREAD (NAAN) FOR
ENHANCED ACCEPTABILITY
Texture of the naans was the main attribute of sensory evaluation. It was
evaluated by a panel of five judges. The highest score for the texture was
8.20, which was achieved by variety LU-26 followed by 8.00 which was
got by the variety LU-31 (Table 6). The results for the texture of the
leavened flat breads of all the wheat varieties/lines were highly significant
(P<0.01) as shown by the analysis of variance (Table 2).
Wheat starch and gluten have limited effect on tortilla texture [Wang and
Flores 1999]. The flour protein and water absorption affect tortilla texture
[Wang and Flores 1999]. Softness in chapatti texture is highly correlated
with flour color and consequently bran content; this may be due to
Zubair Farooq, Salim-ur-Rehman, Masood Sadiq Butt and M. Qamar Bilal
178
increase in water absorption [Navickis and Nelsen 1992]. Generally it was
observed that wheat variety LU-26 was ranked at number one for the
texture of the naans and the variety LU-31 at number two.
Table 6: Comparison of mean scores for sensory evaluation of naans of wheat varieties/lines.
Characteristics
Variety
LU-26
Variety
LU-31
Line
4072
Line
4770
Line
4943
Line
5039
Line
6500
Texture (score) 8.20a 8.00a 6.73b 6.53b 6.93b 6.57b 6.53b
Means with the same letter are not significantly different.
CONCLUSION
Physico-chemical and rheological characteristics of wheat varieties/lines
affect the quality of the end product. Flour characteristics of wheat
varieties/lines have a bearing on the texture of the leavened flat bread
(naan). Wheat variety LU-26 was ranked high for the production of
leavened flat bread (naan).
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