Agricultural Sciences in China
2011, 10(11): 1792-1800 November 2011
© 2011, CAAS. All rights reserved. Published by Elsevier Ltd.
doi:10.1016/S1671-2927(11)60179-X
The Relationship Between Chinese Raw Dumpling Quality and Flour
Characteristics of Shandong Winter Wheat Cultivars
ZHANG Yan1, 2, YE Yi-li2, LIU Jian-jun3, XIAO Yong-gui2, SUN Qi-xin1 and HE Zhong-hu2, 4
1College of Agriculture and Biotechnology, China Agricultural University, Beijing 100193, P.R.China
2Institute of Crop Science/National Wheat Improvement Center, Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China
3Crop Research Institute, Shandong Academy of Agricultural Science, Jinan 250100, P.R.China
4CIMMYT China Office/Chinese Academy of Agricultural Sciences, Beijing 100081, P.R.China
Abstract
Dumpling is one of the most important traditional wheat products in China. Dumpling quality is determined by the
characteristics of both flour and filling, thus improvement of flour quality plays an important role in improving dumpling
quality. Thirty-nine Shandong winter wheat cultivars and advanced lines sown in Jinan, Shandong Province, China, in the
2008-2009 cropping season were used to determine genetic variation in Chinese raw dumpling quality and its relationship
with flour characteristics. Large variations were observed for protein quality parameters in comparison with starch
properties. Variation in color of the raw dumpling sheet was broader than that of sensory evaluation parameters of boiled
dumpling among tested wheat cultivars, indicating the large influence of filling on dumpling color. Two cultivars, Jimai 20
and Zimai 12, were identified as possessing very good quality of raw dumpling, and 21 cultivars and advanced lines
showed good quality. Protein and total starch content influenced the L* value of raw dumpling sheets. L* value at 0 and
2 h after sheeting were significantly influenced by protein content (r=-0.46 and -0.52, P<0.01) and total starch content (r=0.55
and
0.57, P<0.01), respectively. Flour yellow pigment was significantly corrected with a
*
(r=-0.67 and -0.62, P<0.01) and
b
*
(r
=0.87 and 0.84, P<0.01) value of raw dumpling sheets at 0 and 2 h after sheeting, respectively. Gluten strength
parameters such as farinograph mixing tolerance index (MTI, r=-0.55, P<0.01) were positively associated with appearance.
MTI and energy were also significantly and positively correlated with elasticity of raw dumpling, with r=-0.54 and 0.47
(P<0.01). The positive relationships between peak viscosity (r=0.51, P<0.01), breakdown (r=0.54, P<0.01), and smoothness
of raw dumpling were also observed. Therefore, it is suggested that breeding programs should give more attention to
gluten strength and starch pasting parameters for raw dumpling quality improvement.
key words: Triticum aestivum, protein content, gluten strength, starch pasting properties, raw dumpling
Received 17 Feburary, 2011 Accepted 30 March, 2011
ZHANG Yan, Associate Professor, Tel: +86-10-82108741, E-mail: zhycaas@yahoo.com.cn; Correspondence HE Zhong-hu, Professor, Tel/Fax: +86-10-82108547,
E-mail: zhhecaas@163.com
INTRODUCTION
Dumpling is one of the most important traditional wheat
products in China. Approximately 8% of Chinese wheat
is used to manufacture dumpling (Zhang 2007), and its
use could have a history of more than 1 000 years (Lou
and Yang 2004). It can be served at all three meals
daily, but is more frequently consumed at mid-day and
in the evening. It is especially important in northern
China since dumpling is served as a main dish during
Chinese New Year. Two types of dumpling, i.e., raw
and frozen styles, are generally recognized. Raw dump-
ling is widely consumed because it is considered to
The Relationship Between Chinese Raw Dumpling Quality and Flour Characteristics of Shandong Winter Wheat Cultivars 1793
© 2011, CAAS. All rights reserved. Published by Elsevier Ltd.
have better texture and flavor than the frozen type.
Frozen dumpling is basically marketed in cities and its
consumption is rapidly increasing. Dumplings are
mainly made from wheat flour dough and fillings such
as meat, vegetables, eggs, oil, soybean sauce, salt, and
monosodium glutamate. Dumpling quality is determined
by both the characteristics of the flour and filling.
Therefore, improvement of flour quality plays an im-
portant role in improving dumpling quality.
Up to now, limited studies have been undertaken to
understand the genetic variation of dumpling quality
among different genotypes and effects of flour traits
on dumpling quality. At the same time, laboratory evalu-
ation methods for assessment of dumpling quality still
need to be improved. Therefore, genetic improvement
of dumpling quality is progressing much more slowly
in comparison to white salted noodles and pan bread.
Several studies have focused on the relationship be-
tween flour traits and frozen dumpling quality (FDQ)
(Lou et al. 2004; Zhang et al. 2005 a; Li et al. 2006;
Yang and Sun 2006), and the effects of flour additives
on dumpling quality (Wang et al. 1998; Liang et al. 2006;
Yang et al. 2006). Farinograph development time and
stability, and starch pasting peak viscosity were posi-
tively associated with total score of FDQ (Li et al. 2006;
Yang and Sun 2006). Lou and Yang (2004) reported
that total FDQ score was not significantly associated
with flour protein content and dough extensibility, but
was significantly and negatively correlated with starch
content. However, there is one report that flour water
absorption, farinograph development time, stability and
extensograph energy positively influence the color of
raw dumpling sheet and viscosity of boiled dumpling
sheet without filling; they had negative effects on the
hardness and elasticity of boiled dumpling sheets, but
starch pasting final viscosity and breakdown were posi-
tively associated with viscosity and hardness of boiled
dumpling sheets (Lan et al. 2010). Therefore, much
more efforts are needed to understand the relationship
between wheat flour traits and raw dumpling quality so
as to help wheat breeding programs to respond to con-
sumer and market demands.
Dumplings can also be classified by ingredients of
filling, i.e., meat or vegetable filling styles (Qi 2000;
Tang 2001). Ingredients include meat (pork, beef or
mutton), egg, and many kinds of vegetables such as
cabbage, turnip, carrot, mushroom, Chinese chives,
celery, and other auxiliary materials (e.g., oil, shallot,
ginger, salt, and monosodium glutamate). Meat-filled
dumplings are made from dough, meat, vegetables, and
auxiliary materials, whereas vegetable-filled types are
made from dough, eggs, vegetable and auxiliary
materials, or without eggs. Although no official data
are available, it is generally agreed that Chinese con-
sumption of the two styles is about equal. Therefore,
vegetable-filled dumpling was chosen for this study.
Due to limited land and population pressure, improve-
ments in grain yield, disease resistance, and early ma-
turity have been the major wheat breeding objectives in
China. However, improvements in processing quality,
especially for pan bread and noodles, have become
important objectives during the last 20 years (Zhang et al.
2007). With rapid improvement of living standards in
China, cultivars with high dumpling quality are in ur-
gent demand to suit the needs of increased mechanized
production. The objectives of this study were to deter-
mine the fresh dumpling quality variability present in
Chinese winter wheat germplasm and to understand
the relationship between flour characteristics and color,
appearance, and eating quality of fresh dumpling.
MATERIALS AND METHODS
Wheat samples
Thirty-nine winter wheat genotypes (Table 1) from
Shandong Province, China, including leading cultivars
from 1990 to the present and advanced lines, were used
in this study. Shandong Province is the second largest
wheat producer in China, and the cultivars and lines
used in this study represent most of the current elite
lines for quality improvement in north China. They
were grown during the 2008-2009 cropping season at
the Crop Research Institute, Shandong Academy of Ag-
ricultural Sciences, in Jinan. A randomized complete
block design with three replicates was employed. Test
plots were managed according to local practices. All
samples were free of sprouting damage.
Analytical methods
Wheat samples collected from the three replicates were
1794 ZHANG Yan et al.
© 2011, CAAS. All rights reserved. Published by Elsevier Ltd.
mixed and a 5-kg sample of each cultivar was cleaned,
and tempered overnight. Hard, medium, and soft wheats
were tempered to around 16.5, 15.5, and 14.5% mois-
ture content, respectively. All samples were milled on
a Buhler MLU 202 laboratory mill (Buhler Bros, Ltd.,
Uzwil, Switzerland) according to AACC method 26-
21A to give flours with 60% extraction rates.
Grain hardness and moisture were determined using
the Single Kernel Characterization System (SKCS 4100,
Perten Instruments, Sweden). Flour protein content
(14% MB) was recorded with a NIR analyzer foss-
tecator 1241 (Foss, Högänas, Sweden). Flour color
was measured using a Minolta Chromameter CR 310
(Minolta Camera Co., Ltd., Japan) with the CIE 1976
L*,a*,b* color space equipped with a D65 illuminant.
L* is brightness measured from 0 (black) to 100 (white),
a* is a function of the green to red difference, and b* is
a function of the blue to yellow difference. Farinogragh
and extensograph parameters were obtained according
to AACC approved methods 54-21 and 54-10,
respectively. Starch pasting peak viscosity and break-
down were obtained using a rapid visco analyzer (RVA-
3D super type, Newport Scientific) as described by
Batey et al. (1997). Amylose and starch content were
measured according to Kiribuchi-Otobe et al. (1997).
Flour yellow pigment was determined according to
AACC approved methods 14-15 using a TU-1800PC
UV-VIS spectrophotometer (Beijing Purkinje General
Instrument Co., Ltd., China). Flour polyphenol oxi-
dase (PPO) activity was estimated as described by
Anderson and Morris (2001) using the same spectro-
photometer as flour yellow pigment.
Raw dumpling preparation
Based on our previous unpublished data, the optimum
water absorption for dumpling production was adjusted
to be 41% of flour weight. Dumpling dough was pre-
pared by mixing flour (200 g, 14% MB) with enough
water to achieve 41% water absorption using a Na-
tional pin mixer (USA) for 1 min. After mixing, the
dough was kept in a plastic container for 15 min at
room temperature before passing through the sheeting
rollers of a laboratory noodle machine (Ohtake 150,
Tokyo, Japan). Sheeting occurred once with a 4-mm
roll gap setting, and then four times at 3-mm roll gap
settings including no folding on the third pass. During
the sheeting process, a small amount of dry flour was
sprinkled onto the sheets to avoid sticking to the rollers.
The sheet dough was kept again in a plastic storage
container for 15 min at room temperature. Subsequently,
the reduction in sheet thickness was achieved by suc-
cessive passes through roll gaps of 2.2 and (1.5±0.05)
mm. The gap between the rollers for the final pass
was determined precisely using a test piece cut from
the main sheet after the previous pass. The final sheets
were cut into round pieces with a round stainless steel
cutter (6 cm diameter) to obtain dumpling sheets.
The filling was a blend of ingredients (200 g of mac-
erated cabbage, 100 g of fried egg, 10 g of oil, 6 g of
shallot, 3 g of ginger, 3 g salt, and 1 g monosodium
glutamate) mixed in a plastic container. Fried egg made
from equal amounts of egg and oil was used in the
vegetable filling to reduce the variation of filling in dif-
ferent tests. The dumpling sheets were shaped to con-
tain 3 g filling, shaped as a dumpling, and stored in a
flat dish at room temperature. Raw dumplings (25 units
per sample) were boiled for 5 min in 2 L of boiling
water. Four cooking sessions were processed at the
same time. After boiling, the dumplings were rinsed in
running cold tap water for 1 min. Sensory evaluation
was performed with at least five skilled panelists and
finished within 10 min.
Table 1 Thirty-nine cultivars and advanced lines assessed for raw
dumpling quality
Cultivar Type Cultivar Type
Jimai 19 Cultivar Taishan 223 Cultivar
Jimai 20 Cultivar Tainong 18 Cultivar
Jimai 22 Cultivar Wennong 6 Cultivar
Jimai 5319 Cultivar Weimai 8 Cultivar
Jimai 6097 Cultivar Yannong 19 Cultivar
Jimai 6487 Cultivar Yannong 23 Cultivar
Jimai 7251 Cultivar Yannong 24 Cultivar
Jimai 7327-2 Cultivar Zimai 12 Cultivar
Jinan 17 Cultivar Zhongmai 155 Line
Jining 13 Cultivar BPT08058 Line
Jining 16 Cultivar Jimai 035037 Line
Linmai 2 Cultivar Jimai 037042 Line
Linmai 6 Cultivar Jimai 046402 Line
Liangxing 66 Cultivar Jimai 056852 Line
Lumai 21 Cultivar Jimai 065504 Line
Lumai 23 Cultivar Jimai 066324 Line
Shannong 15 Cultivar Jimai 076128 Line
Taishan 21 Cultivar Jimai 077019 Line
Taishan 23 Cultivar Jimai 077072 Line
Taishan 24 Cultivar
The Relationship Between Chinese Raw Dumpling Quality and Flour Characteristics of Shandong Winter Wheat Cultivars 1795
© 2011, CAAS. All rights reserved. Published by Elsevier Ltd.
Raw dumpling sensory evaluation
Although an official method for sensory evaluation of
Chinese raw dumpling (SB/T 10138/93) (Chinese Min-
istry of Commerce 1993) has been used since 1993, it
has been suggested that improvements can be made.
The scoring system, including color (weighting factor
10), brightness (10), transparency (10), resilience (15),
stickiness (15), smoothness (10), resistance at boiling
(15), and soup characters (15), has two problems.
Firstly, evaluation of soup characters is not easy; de-
grees of clearness or feculence of water after cooking
dumpling is estimated by panelists. However, most
panelists have difficulties in giving precise or consis-
tent scores for soup characteristics. Secondly, firm-
ness is not included in the evaluation system. High
quality raw dumpling sheets should be characterized
with whiteness and brightness for color, softness and
resilience, lack of stickiness and smoothness of texture.
Because color and firmness are considered to be more
important parameters for scoring raw dumpling by the
industry, firmness instead of soup characteristics was
adopted in a modified scoring system. For appearance
of raw dumplings, panelists should assess the degrees
of flatness, and lack of gas bubbles and rupturing of
dumpling sheets. Flatness requires that the dumpling
sheet surface is flat and uniform, has no gas bubbles,
and rupture is mainly considered to ensure that the
sheets have no cracks after boiling. Resistance at boil-
ing is similar to an assessment of appearance, and was
therefore replaced by appearance in the modified scor-
ing system. Based on the noodle evaluation system
described by Zhang et al. (2005b), the modified scor-
ing system for dumpling included six parameters, viz.,
color (20), appearance (20), firmness (20), elasticity
(20), stickiness (10), and smoothness (10). Four
samples were tested at each panel session including the
Chinese commercial flour Xuehuafen as a control.
Samples under test were compared with the control
and a score was assigned to each parameter. The pan-
elists firstly compared color and appearance of boiled
dumplings, and then opened the fringe of the dumpling
and removed the filling, followed by evaluations of
firmness, elasticity, stickiness, and smoothness of boiled
dumpling sheets.
Color measurements of dumpling sheets
Color of raw dumpling sheets was measured with a
Minolta Chromameter CR 310 (Minolta Camera Co.,
Ltd., Japan) with the CIE 1976 L*,a*,b* color space
equipped with a D65 illuminant. The sheets were mea-
sured on a Royal Australian Cereal Institute (RACI) stan-
dard backing tile, with three measurements being made
on each side of the dumpling sheet. Raw dumpling
sheets were measured after sheeting (0 h), and again
after 2 h of storage in a covered plastic container at
25°C.
Statistical analysis
SAS (Statistics Analysis System, SAS Institute, Cary,
NC) was employed to compute means, standard
deviations, and correlation coefficients.
RESULTS
Grain and flour characterization of tested wheat
cultivars
Means, coefficients of variation (CV), and ranges of
grain hardness, protein content, farinograph and
extensograph parameters and starch quality parameters
including peak viscosity, breakdown, final viscosity,
amylose and total starch content for tested wheat culti-
vars are presented in Table 2. As expected, large varia-
tions were observed for protein quality parameters in
comparison with starch traits. The largest variations
involved dough development time, stability, MTI, energy,
and maximum resistance, with CVs of 40.5, 71.6, 53.4,
53.1, and 57.0%, respectively. Only small variations in
amylose and total starch contents were observed, with
CVs of only 2.7, and 1.5%, respectively.
Variation in raw dumpling quality
Broad variations were observed for a* and b* values for
raw dumpling sheets at 0 and 2 h, but not for L* values
(Table 3). The largest variations for a* values with
CVs of 89.1% at 0 h and 52.3% at 2 h, and wide varia-
1796 ZHANG Yan et al.
© 2011, CAAS. All rights reserved. Published by Elsevier Ltd.
tion for b*values with CVs of 11.3% at 0 h and 11.5%
at 2 h occurred with raw dumpling sheets. This indi-
cated that variation for color of raw dumpling sheet
might mainly come from the variation in a* and b* values,
but not in L* values. Yannong 24, Zhongmai 155,
Liangxing 66, Jimai 20, and Yannong 23 performed best
in color of raw dumpling sheets. They could therefore
be used as parents in crossing programs for flour color
improvement. On the other hand, Jinan 17, Jimai 7327-2,
Jimai 077072, Wennong 6, and Jimai 037042 were iden-
tified as having poor raw dumpling sheet color.
There were small variations in sensory evaluation
parameters of boiled dumplings in comparison with the
color of raw dumpling sheets. The range in CV for
sensory evaluation parameters of boiled dumpling was
4.9-9.0%. Variation in color of boiled dumplings was
significantly smaller than that of raw dumpling sheets.
The reason for the discrepancy might be that the dump-
ling filling significantly influences panelists visual as-
sessments of boiled dumpling color, hence reducing
the differences in color of boiled dumpling among
genotypes. Variations in color, appearance, and firm-
ness of boiled dumplings were slightly larger than those
for elasticity, stickiness, and smoothness.
Chinese commercial flour, Xuehuafen, used as the
control in this study is considered to be of good quality
for noodles and dumplings. Relative to the assessment
score of 70.0 for Xuehuafen in this study, raw dump-
ling scores above 75.0 were considered very good,
scores of 70.1-75.0 good, scores of 65.0-70.0 fair,
and scores below 65.0 were poor (Table 4). Cultivars
including Jimai 20 (total score 78.3) and Zimai 12 (76.0)
were identified as possessing very good boiled fresh
dumpling quality. Jimai 20 was the leading cultivar in
the Yellow and Huai Valley, and was characterized with
very good white salted noodle quality (Ye et al. 2010).
Zimai 12 is also a released cultivar. Twenty-one culti-
vars and advanced lines had good fresh dumpling
quality. Overall, Chinese winter wheat generally had
acceptable quality for boiled fresh dumpling. This out-
come could be due to the improvement of pan bread
and noodle quality that has occurred in Chinese breed-
ing programs during the past 20 years.
Relationship between grain and flour traits and
quality of raw dumpling
Correlation coefficients between quality traits and color
of raw dumpling sheets are presented in Table 5. Pro-
tein content and total starch content mainly influenced
L* value of raw dumpling sheets. Correlation coeffi-
cients between protein content, total starch content and
L* value at 0 and 2 h after sheeting were -0.46 (P<0.01),
-0.52 (P<0.01), 0.55 (P<0.01), and 0.57 (P<0.01),
respectively. Parameters relative to protein quality such
as water absorption, development time, stability, and
maximum resistance showed moderately negative ef-
fects on L* and a* values of raw dumpling sheets, and
starch pasting peak viscosity, breakdown and final vis-
cosity showed slight and positive effects on L* values.
Flour yellow pigment was significantly associated with
a* and b* values at 0 and 2 h after sheeting, with r=-0.67
(P<0.01), -0.62 (P<0.01), 0.87 (P<0.01), and 0.84 (P<0.01),
Table 2 Mean, coefficients of variation (CV), and ranges in grain
quality trait parameters for 39 wheat cultivars
Trait Mean CV (%) Range
Grain hardness 58.9 28.8 20.7-79.0
Protein content (%, 14% MB) 12.6 5.7 11.1-14.3
Water absorption (%) 65.9 6.6 56.1-72.5
Development time (min) 3.8 40.5 1.9-8.3
Stability (min) 6.4 71.6 1.2-17.9
Mixing tolerance index (BU)1) 53.7 53.4 16.0-140.0
Extensibility (mm) 180.7 14.9 79.2-253.3
Max. resistance (BU) 215.0 57.0 32.5-490.1
Peak viscosity (RVU) 195.8 16.1 114.6-263.6
Breakdown (RVU) 148.5 19.1 60.5-191.8
Final viscosity (RVU) 235.3 15.9 116.2-289.3
Amylose (%) 22.8 2.7 21.2-23.8
Total starch (%) 80.2 1.5 78.1-83.1
Flour yellow pigment (mg kg-1) 1.9 29.5 1.2-3.6
Flour PPO [A475/(g×min)×103] 2.7 39.2 0.4-4.7
1) Mixing tolerance index (MTI) was measured by farinograph.
Table 3 Mean, coefficients of variation (CV) and ranges of L*,a*,
and b* values of raw dumpling sheets and sensory evaluation
parameters of boiled dumplings for 39 wheat cultivars
Parameter Mean CV (%) Range
L* 0 h 84.80 0.8 83.38-85.99
a* 0 h 0.52 89.1 -0.75-1.47
b* 0 h 20.56 11.3 16.56-26.01
L* 2 h 82.47 1.0 80.81-84.37
a* 2 h 0.97 52.3 -0.30-2.09
b* 2 h 23.63 11.5 19.21-28.62
Sensory evaluation
Color (20) 13.8 9.0 11.4-16.6
Appearance (20) 14.4 9.0 10.8-16.3
Firmness (20) 13.9 8.9 11.6-16.0
Elasticity (20) 14.3 7.2 12.0-16.4
Stickiness (10) 7.1 7.4 6.1-8.0
Smoothness (10) 7.1 5.1 6.3-7.7
Total score (100) 70.5 4.9 63.5-78.3