close

Вход

Забыли?

вход по аккаунту

?

star.201700156

код для вставкиСкачать
RESEARCH ARTICLE
Acorn Starch
www.starch-journal.com
Steady Shear Rheological Properties of Native and
Hydrothermally Modified Persian Acorn (Quercus brantii
Lindle.) Starches
Hooman Molavi and Seyed M. A. Razavi*
considerable amount (about 58%) of
starch.[2] Because of the similarity of acorns
to cereals,[3] they have been used in the
formulation of some foods.[4–8] But, the
existence of significant amounts of tannins
has made it difficult to use in foods. So, the
fruits are left to rot or used as animal feed or
the trees are mainly underexploited to
produce charcoal. One of the applicable
ways to use this immense natural source is to
extract starch from acorns. That way, as well
as introducing a new source of starch, oak
trees will be preserved. Considering the fact
that the trees do not need any agricultural
practices, the price of raw materials is at least
because the fruits just need to be gathered at
the ripening stage. On the other hand, the byproducts of this process like tannins, tannic
acid, and oil are valuable.[7,9,10] Some other
researchers have also mentioned the benefits of starch extraction from acorns.[11,12]
Starch is a valuable raw material which
is used for improving consistency and
texture of foods. Rheological properties
affect not only the processing conditions,
but also the customer attitudes toward a
food. So, knowledge of starch solutions as
well as the relationship between apparent
viscosity and starch concentration are of
great importance to successfully formulate and process starch-containing foods.
Several models have been used to describe the flow behavior
of different hydrocolloids.[13–15] The power law, Herschel–
Bulkley, Bingham, and Sisko models are of important models
used to to evaluate the time-independent flow behavior of
wheat starch.[16] The power law model reveals the consistency
coefficient as well as flow behavior index of starch (i.e., shearthickening or shear-thinning properties of starch) and the
Casson model demonstrates the yield stress as well as plastic
viscosity. These are actually the rheological parameters which
can be used to describe the flow behavior and viscoplastic
properties and are crucial while dealing with starch solutions,
for example, to choose the kind of pump which is needed and
the amount of energy required to transport the starch solution
and finally to estimate the viscosity of product under different
conditions of shear or temperature. Moreover, both models
manifest the apparent viscosity at a specified temperature and
shear rate.
The steady shear rheological properties of native and hydrothermally modified
Persian acorn starches at different concentrations (1, 2, and 3%) and
temperatures (25, 40, 55, and 70 C) were assessed.
The rheological data of starch dispersions were fitted to the power law
(R2 ¼ 0.769–0.980) and Casson models (R2 ¼ 0.904–0.994). According to the
power law model, all native and hydrothermally modified starches presented
shear-thinning behavior with the flow behavior index between 0.697 and
0.933. The consistency coefficient (k) and apparent viscosity (ηa,100) of
starches were in the range of 3.157–246.167 mPa sn and 2.212–74.443 mPa s,
respectively. Based on the Casson model, the plastic viscosity (ηc) and yield
stress (τ0c) of starches were in the range of 1.977–41.167 mPa s and 0.333–
506.667 mPa, respectively. All rheological parameters, except for the flow
behavior index, increased with increasing in concentration, and decreased
with temperature. The temperature dependency of all the starches was well
described by the Arrhenius model (R2 ¼ 0.837–0.999). The activation energy
(Ea) values were in the range of 4.47–12.96 kJ mol1. The concentration
dependency of all the starches in the temperature range of 25–70 C was well
fitted to the power law (R2 ¼ 0.919–0.998) and exponential (R2 ¼ 0.970–0.999)
models. Generally, the rheological parameters such as k, ηa,100, ηc, and τ0c of
native starch were maximum and those of annealing (ANN) starch were
between those of native and heat-moisture-treatment (HMT) starches. These
properties for dually modified starches were between those of single ones,
showing that the second treatment could negate the effects of the first one.
1. Introduction
Since the commercial sources of starch (such as wheat and corn)
are used in many other industries, it is necessary to find local
sources of starch like acorns. Acorns are the fruits of oak trees
belonging to the genus Quercus, which more than 300 species are
distributed in Eurasia, North and Central America, and North
Africa.[1] Quercus brantii, also named Persian (Iranian) oak, is the
predominant species in Iran which its fruits (acorns) contain
Dr. H. Molavi, Prof. S. M. A. Razavi
Department of Food Science and Technology, Food Hydrocolloids
Research Center
Ferdowsi University of Mashhad (FUM), PO Box: 91775-1163,
Mashhad, Iran
E-mail: s.razavi@um.ac.ir
DOI: 10.1002/star.201700156
Starch/Stärke 2017, 1700156
1700156 (1 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
Native starches present unique characteristics; however, they
cannot meet all the demands of different industries. Therefore,
native starches are modified to be adapted to final products.
Physical modifications like heat moisture treatment (HMT) and
annealing (ANN) are of most interesting ones because no
chemicals are used in these modifications; therefore, there are
no health hazards regarding consuming these modified
products. Both HMT and ANN are thermal processes that
modify granular structure of starch without gelatinization takes
place. The difference between these two processes is that HMT is
carried out at high temperatures (above gelatinization temperature), and low levels of moisture; in contrast, ANN is performed
at low temperatures (below gelatinization temperature) and in
excess of water. Both treatments result in structural changes
within the amorphous and crystalline regions to different
extents.[17–19] Hydrothermally modified starches have been used
in some industries like canning, frozen foods, and fat replacer
technology;[20] pouch packed, and resistant starch production;[21]
and biodegradable films.[22]
The basic physico-chemical properties of native Persian acorn
starch revealed that it could be used as a viscosifying agent like
wheat starch meanwhile it could tolerate more severe conditions
during processing of a product. In addition, hydrothermal
modifications make it more resistant to destructive conditions
(like high temperatures, acidic media, and shearing).[23] Despite
the fact that this kind of starch is going to be produce
commercially in the country, the next step is to reveal its
rheological properties. Since there is no information on the
rheological properties of Persian acorn starch, so the aim of this
research was to investigate the steady shear rheological
properties of native (to reveal its applications to desirable
industries) and hydrothermally modified Persian acorn starches
in order to broaden its applications by using safe methods. In
this study, the effects of concentration (1–3%, w/w) and
temperature (25–70 C) on the rheological parameters have also
been investigated.
2. Experimental Section
2.1. Preparation and Extraction Procedure
Acorns (Q. brantii) were provided from the Lordegan region,
Chaharmahal va Bakhtiari Province, Iran, at the maturity stage
and kept in a cool, dark place until the experiments began. The
preparation, milling, and extraction procedures were as follows:
1) pre-drying at 40 C/24 h in an oven (Memmert UNB 500,
Germany), 2) peeling and cutting into small pieces, 3) final
drying at 40 C in the same oven, 4) milling the pieces using a
hammer mill (model 2000, Zagros Co., Iran) and passing the
flour through a 1-mm sieve, 5) starch extraction using the low
shear, alkaline pH, and successively three sieves (LSA3S)
method. Starch extracted by this method has been shown to
have high purity and yield and its physical and chemical
properties is less affected.[24] The isolated starch was dried
overnight in the aforementioned oven at 40 C.[25] The proximate
analysis (%, dry basis) showed that Persian acorn starch
contained 0.04 0.02% nitrogen, 0.28 0.04% lipids
(0.07 0.02% for the free lipids and 0.21 0.02% for the bound
Starch/Stärke 2017, 1700156
lipids), and 0.175 0.030% ash. The amylose content was also
26.5 0.2%.[23]
2.2. Hydrothermal Treatments
2.2.1. Heat-Moisture Treatment (HMT)
Native starch was weighed into glass containers and its moisture
content was adjusted to 20% by adding the appropriate amounts
of distilled water. After sealing, the containers were kept at room
temperature for 24 h and then heated at 110 C/24 h in the oven.
Then, the containers were opened and the treated starch samples
were dried to uniform moisture content (10%).[26]
2.2.2. Annealing (ANN)
Acorns slurry (70% moisture) was heated at 50 C/24 h in a water
bath (Memmert WNB 29) and then centrifuged (Sigma, Germany)
at 2000 g for 10 min and the supernatant was discarded. Next, the
annealed starch was washed once with deionized water and finally
dried at 40 C in the aforementioned oven.[27]
2.2.3. Dual Modifications (HMT-ANN and ANN-HMT)
For HMT-ANN, heat-moisture treated starch (section 2.2.1) was
subjected to annealing treatment (section 2.2.2) and for ANNHMT, annealed starch (section 2.2.2) was subjected to heatmoisture treatment (section 2.2.1).
2.3. Steady Shear Rheological Measurements
Native and hydrothermally modified starch dispersions (1, 2, and
3% w/w) were prepared by mixing starch with deionized water in
glass containers. After sealing, they are gently stirred at ambient
temperature for 30 min. Afterward the samples were heated in a
Memmert water bath (WNB 29, Germany) at 95 C for 30 min with
mild agitation. The samples, then, were immediately transferred
into UL Adapter (304 s s1, Brookfield, USA) and rheological data
were acquired at 25, 40, 55, and 70 C using a DV III ULTRA
programmable rheometer (Brookfield). The dependency of
rheological properties on shear rate may be described by different
models like Bingham, power law, Herschel–Bulkley, Casson,
etc.[13] Since the power law (Eq. 1) and Casson (Eq. 2) models gave
more satisfactory results, they were chosen to describe flow
behavior over the shear rate in the range of 4–300 s1:
τ ¼ kp γ_ n
ð1Þ
where τ is shear stress (Pa), γ_ is shear rate (s1), kp is consistency
coefficient (Pa sn) and np is flow behavior index ().
τ 0:5 ¼ k0C þ kC γ_ 0:5
ð2Þ
where k0C (Pa0.5) and k0C (Pa0.5 s0.5) are the intercept and slope of
plot of (τ0.5) versus (γ0.5), respectively. Then, the magnitude of
1700156 (2 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
k0C2 and kC2 have been used as the Casson yield stress (τ0C, Pa)
and Casson plastic viscosity (ηC, Pa s), respectively.
Moreover, an Arrhenius-type model (Eq. 3) was applied to
investigate the effect of temperature (25, 50, 55, and 70 C) on
apparent viscosity at shear rate of 100 s1 (ηa,100) of starch
dispersions:
ηa;100 ¼ A exp
Ea
RT
3. Results and Discussion
3.1. Native Acorn Starch
As shown in Table 1, shear-stress–shear-rate data determined
for native Persian acorn starch at different concentrations
(1, 2, and 3%) and temperatures (25, 40, 55, and 70) were well
fitted to both the power law model (R 2 ¼ 0.792–0.968) and
Casson model (R2 ¼ 0.914–0.981); however, the Casson
model presented the best fitting (Table 1). According to
the power law model, native acorn starch presented shearthinning behavior at all concentrations and temperatures
because the flow behavior indices were below 1 (n ¼ 0.697–
0.810). Kim and Yoo [29] observed the same shear-thinning
behavior for Korean acorn starch dispersion in the
concentration range of 4–7%. The shear-thinning behavior
of starch dispersions may be explained by gradual orientation of molecules in the flow direction and breaking
hydrogen bonds present between starch molecules
and water as shearing continues.[30] Some other researchers [31–33] have mentioned that as shear rate increases, longchain molecules untie, therefore, the intramolecular resistance to flow (i.e., viscosity) decreases. Moreover, particles
and molecules which are dissolved to a great extent may
disappear as shear rate increases. So, this reduces the effect
of particle size and consequently reduces the viscosity. At the
temperature of 25 C, the flow behavior index decreased with
increasing in concentration, showing a more pseudoplastic
behavior at higher concentrations. The same behavior has
been reported on canary seed starch[34] and wheat starch. [16]
However, at higher temperatures, the flow behavior index
values first increased and then decreased as concentration
increased. The flow behavior indices of Persian acorn
starch were higher than those of Korean acorn starch
(0.22–0.45),[29] mainly due to the lower concentrations. At
each concentration, there was no specific change in flow
behavior index as temperature increased. The same results
were observed by Kim and Yoo.[29]
ð3Þ
where A is the proportionality constant (or apparent viscosity at
infinite temperature, Pa s), Ea is the activation energy (kJ mol1),
R is the universal gas constant (kJ mol1 K1), and T is absolute
temperature (K). The value of Ea at each concentration were
calculated from the regression analysis of ln ηa,100 versus 1/T.
The effect of concentration on apparent viscosity at shear rate
of 100 s1 (ηa,100) was described by the power law (Eq. 4) and
exponential (Eq. 5) models:[28]
ηa100 ¼ a1 Cb1
ð4Þ
ηa100 ¼ a2 exp ðb2 CÞ
ð5Þ
where, a1, b1, a2, and b2 are constants, and C is the concentration
of starch dispersion.
2.4. Data Analysis
Analytical determinations for the samples were performed in
triplicate and means and standard deviations were reported
using Microsoft Excel (2013, Microsoft, USA). The Rheocalc
software ver. 3.2 (Brookfield) was used to acquire rheological
parameters. The toolbox of MATLAB programming software
(R2016b, The Math Works, Inc., USA) was used for curve fitting.
Table 1. Effect of temperature and concentration on the parameters of the power law and Casson models and apparent viscosity (ηa,100) of native
Persian acorn starch.
Power law model
Temp. ( C)
25
40
55
70
n
Casson model
ηC (mPa s)
τ0C (mPa)
R2
0.914
2.813 0.095
6.000 1.000
0.971
3.694 0.185
0.760 0.035
0.932
8.233 1.214
92.667 17.243
0.970
14.681 2.241
246.167 24.755
0.750 0.017
0.869
41.167 8.730
494.000 36.428
0.929
74.443 10.718
9.397 3.100
0.760 0.053
0.856
2.400 0.142
3.000 3.000
0.937
2.857 0.354
2
29.000 6.250
0.810 0.040
0.968
7.653 0.190
44.667 10.017
0.975
11.780 0.359
3
204.900 23.684
0.740 0.026
0.873
29.633 1.557
497.667 66.763
0.930
58.829 1.189
Conc. (%)
kp (mPa s )
n ()
R
1
10.633 0.709
0.780 0.020
2
44.767 1.069
3
1
2
ηa,100 (mPa s)
1
8.0433 0.805
0.767 0.025
0.812
2.250 0.118
1.000 0.000
0.925
2.560 0.126
2
24.133 4.676
0.803 0.042
0.966
6.363 0.208
29.333 6.658
0.980
9.375 0.217
3
187.100 19.050
0.697 0.021
0.917
20.133 2.082
506.667 72.280
0.948
45.300 1.428
1
7.070 2.125
0.770 0.072
0.792
2.117 0.179
0.333 0.577
0.914
2.212 0.0169
2
21.433 5.052
0.797 0.050
0.957
5.540 0.165
23.667 3.215
0.981
8.061 0.024
3
116.167 30.502
0.763 0.067
0.865
16.967 0.252
416.667 20.648
0.927
37.947 0.968
Starch/Stärke 2017, 1700156
1700156 (3 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
The kp and ηa,100 values of native acorn starch increased as
concentration increased (Table 1). Rha[35] explained this
phenomenon by interactions between particles because at
higher concentrations, lower amount of solvent exists; therefore,
the accumulation of particles increases the consistency. Kim and
Yoo[29] mentioned that the dependency of consistency coefficient
and apparent viscosity on starch concentration could make
valuable information available to estimate the rheological
properties of starch-containing products. As temperature
increased, ηa,100 and kp decreased (Table 1), which may be due
to the increase in intermolecular spaces within the starch matrix
resulted from thermal expansion.[36] As temperature increased
from 25 to 70 C, the ηa,100 of Persian acorn starch dispersions at
1, 2, and 3% concentrations decreased 33.5, 52.1, and 52.8%,
respectively. The corresponding values for Korean acorn
dispersions at 4, 5, 6, and 7% concentrations were 71.9, 86.2,
79.0, and 77.8%, respectively.[29]
The Casson model was also investigated to evaluate the plastic
viscosity (ηc) and yield stress (τ0c) of acorn starch. The ηc values
ranged from 2.117 (for 1% concentration at 70 C) to
41.167 mPa s (for 3% concentration at 25 C) and the τ0c values
were between 0.333 (for 1% concentration at 70 C) to
506.667 mPa (for 3% concentration at 55 C) (Table 1). The
maximum ηc of native acorn starch at the concentration of 3%
was comparable with that of canary seed starch (CO5041 variety)
at the concentration of 4% at 25 C.[34] The values of τ0c (at 5% of
concentration and 25 C) were 34.9 Pa for sweet potato starch,[37]
19.2 Pa for rice starch, and 10.7 Pa for tapioca starch.[38] The τ0c
and ηc values of potato starch (at 3% of concentration and 25 C)
were 0.71 Pa and 1.389 Pa s. The greater viscosity of potato starch
has been attributed to its higher swelling power.[39] The τ0c and ηc
values of native acorn starch increased at each temperature as
concentration increased. The increase in the amounts of these
parameters were more noticeable at higher concentration (3%).
These results were inconsistent with those of canary seed,[34]
chestnut,[40] and acorn[29] starches, probably due to different
concentration range studied. Since a threshold starch content
produces complete interactions between polymers and higher
amylose content would limit the increase in viscosity;[41]
however, in this study (concentration range of 1–3%) that
threshold was not reached. Therefore, an exponential increase in
viscosity was observed. Generally, the amounts of ηc and τ0c
decreased as temperature increased. The same results were
observed by Irani et al.[34]
The temperature dependency of ηa,100 can be described by
Arrhenius model (Eq. 3) in which ηa,100 decreases with
increasing in temperature exponentially. Some researchers have
shown this for starch dispersions with high coefficient of
determinations.[34,42,43] Activation energy (Ea) is used to
determine the relative sensitivity of starch viscosity to temperature changes.[42] The Ea values for native Persian acorn starch
were in the range of 9.39–12.96 kJ mol1 with high determination coefficients (0.977–0.997) (Table 2). The Ea increased slightly
with increasing in concentration from 1 to 3%. It was consistent
with the study of Kim and Yoo[29] on Korean acorn starch but the
values in their study were higher (16.5–19 kJ mol1) probably
due to the higher concentration range (4–7%). Higher values of
Ea indicates that the viscosity of starch dispersions at higher
concentrations are more sensitive to temperature changes.
Starch/Stärke 2017, 1700156
Table 2. Activation energy (Ea) of native and hydrothermally modified
Persian acorn starch dispersions as a function of concentration.
Starch
Native
HMT
ANN
HMT-ANN
ANN-HMT
Concentration (%)
Ea (kJ mol1)
R2
1
9.39
0.977
2
11.51
0.997
3
12.96
0.997
1
4.47
0.837
2
11.36
0.986
3
11.37
0.996
1
6.03
0.911
2
12.00
0.994
3
12.32
0.993
1
5.04
0.931
2
10.99
0.982
3
12.20
0.996
1
4.70
0.884
2
11.15
0.951
3
11.54
0.999
HMT, heat-moisture treatment; ANN, annealing.
Table 3 shows the relationship between the concentration
and the ηa,100 of Persian acorn starch dispersions at
different temperatures described by the power law (Eq. 4)
and exponential (Eq. 5) models. As seen, the coefficients of a
and b of native starch for both models decreased as
temperature increased and the exponential model
(R2 ¼ 0.999) presented more acceptable results than did the
power law model (R2 ¼ 0.997–0.998). The results were
inconsistent with those of Kim and Yoo[29] on Korean
acorn starch dispersions since the power law model
(R2 ¼ 0.998–0.999) was better than the exponential model
(R2 ¼ 0.985–0.996). However, they mentioned that the exponential model was also suitable for showing the relationship
between the concentration and ηa,100 of acorn starch (except
for starch dispersion at 40 C).
From industrial point of view, in our previous work, it had
been shown that native acorn starch possessed high viscosifying
ability compared to some other starch sources like wheat
starch;[23] however, in the present study, it was demonstrated that
the first consideration when dealing with native acorn starch was
to take the Casson model into account as the base of engineering
calculations. Consequently, always a threshold yield is needed
which is increased exponentially as concentration increases. It is
crucial for the calculations of pumps which are going to be
applied to transport a specific concentration of starch solution at
a prescribed temperature. Moreover, it was shown that
increasing in the ηa,100 also followed the Arrhenius model
which is necessary to estimate ηa,100 at different temperatures
during the process. Furthermore, for more accurate prediction of
ηa,100 based on concentration, it would be better to take the
exponential model into account since it showed better fitting
quality.
1700156 (4 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
Table 3. Concentration dependence of the apparent viscosity (ηa,100) of native and hydrothermally modified Persian acorn starches at different
temperatures.
ηa,100 ¼ a1Cb1
Starch
Temperature ( C)
Native
HMT
ANN
HMT-ANN
ANN-HMT
a1 10
3
b1
ηa,100 ¼ a2exp(b2C)
R
2
a2 10
3
b2
R2
25
1.006
3.917
0.997
0.606
1.604
0.999
40
0.825
3.883
0.998
0.494
1.593
0.999
55
0.710
3.781
0.997
0.433
1.550
0.999
70
0.697
3.636
0.997
0.391
1.525
0.999
25
1.464
2.356
0.983
0.843
1.050
0.998
40
1.115
2.382
0.976
0.633
1.064
0.996
55
1.140
2.116
0.964
0.647
0.987
0.992
70
1.098
2.059
0.946
0.622
0.950
0.983
25
0.800
3.875
0.997
0.490
1.582
0.999
40
0.641
3.812
0.996
0.398
1.555
0.999
55
0.518
3.833
0.994
0.335
1.550
0.999
70
0.480
3.739
0.992
0.303
1.523
0.998
25
1.327
2.338
0.970
0.751
1.05
0.994
40
1.051
2.339
0.945
0.646
1.022
0.980
55
1.170
2.001
0.930
0.665
0.927
0.975
70
1.154
1.869
0.919
0.659
0.879
0.970
25
1.012
3.107
0.990
0.635
1.294
0.999
40
0.970
2.909
0.988
0.551
1.256
0.998
55
0.911
2.783
0.980
0.513
1.213
0.995
70
0.836
2.715
0.974
0.470
1.189
0.992
HMT, heat-moisture treatment; ANN, annealing.
3.2. Effect of Heat-Moisture Treatment
HMT starch, like native one, presented shear-thinning behavior
at all concentrations and temperatures (Table 4); however, the
flow behavior index values (n ¼ 0.760–0.847) were greater than
those of native starch (n ¼ 0.697–0.810). So, shear-thinning
behavior was lowered on hydrothermal modification of Persian
acorn starch. There were not any definite pattern in the flow
behavior indices as temperature or concentration increased.
Since HMT starch had lower amylose leaching than did native
starch,[23] there has been less amylose chains available in the
system and hence their orientation and untying have taken place
more easily. So, the pseudoplasticity decreased after applying
HMT.
The kp and ηa,100 values of HMT starch increased as
concentration increased (Table 4); nonetheless, the extent of
this increase was much lower than that of native starch. As
temperature increased, ηa,100 and kp decreased (Table 4); still, the
range of this decrease in ηa,100 for 1–3% concentration was
between 0.612 and 8.858 mPa s which was much limited
compared to that of native starch (1.482–36.495 mPa s). The
lower kp and ηa,100 values of HMT starch could be attributed to its
lower amylose leaching and swelling power values. In addition,
other factors like its lower mean diameter and length/width ratio
might be effective; moreover, viscosity parameters of HMT
starch obtained by RVA, such as peak, trough, and final
Starch/Stärke 2017, 1700156
viscosities were also lower than those of native acorn starch.[23]
Hoover and Vasanthan[44] mentioned that the comparison of the
flow properties of native starches with the modified ones would
result in a better understanding of the effect of physico-chemical
properties of starch on flow properties. They showed that HMT
decreased the consistency coefficient of wheat, lentil, and potato
starches. This was attributed to the reduction in swelling power
and amylose leaching. They also observed that the flow behavior
index of wheat, lentil, and potato starches increased while that of
oat starch decreased. They related these observations to changes
in granular volume which affected the resistance of the granule
to deformation and disintegration.
The ηc values of HMT starch ranged from 1.977 mPa s (for 1%
concentration at 70 C) to 11.633 mPa s (for 3% concentration at
25 C) and the τ0c values were between 0.333 (for 1%
concentration at 50 C) and 106.333 mPa (for 3% concentration
at 55 C) (Table 4). In comparison with native starch, it could be
observed that the range of the ηc and the τ0c decreased
considerably on HMT. The ηc and the τ0c values of HMT starch
increased at each temperature as concentration increased but not
as high as those of native starch. Moreover, the values of the ηc
and the τ0c at each concentration mainly decreased as
temperature increased.
The Ea values of HMT starch were in the range of
4.47–11.37 kJ mol1 with relatively high determination coefficients (0.837–0.996) (Table 2), indicating the dependence of ηa,100
1700156 (5 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
Table 4. Effect of concentration and temperature of on the parameters of the power law and Casson models and apparent viscosity (ηa,100) of
HMT acorn starch.
Power law model
Temp. ( C)
25
40
55
70
n
Casson model
ηC (mPa s)
τ0C (mPa)
R2
ηa,100 (mPa s)
0.823
2.337 0.038
2.333 0.577
0.931
2.825 0.060
0.972
4.947 0.398
11.667 2.082
0.989
6.581 0.601
0.781 0.010
0.962
11.633 0.551
106.333 8.737
0.969
19.727 0.909
0.777 0.064
0.779
2.253 0.154
0.333 0.578
0.910
2.354 0.151
0.803 0.050
0.933
3.777 0.440
8.000 3.606
0.984
4.931 0.387
42.467 10.498
0.790 0.044
0.957
9.713 0.811
69.000 23.302
0.971
15.518 1.008
2.260 0.300
Conc. (%)
kp (mPa s )
n ()
R
1
9.150 2.058
0.760 0.046
2
13.633 0.306
0.847 0.015
3
55.367 4.464
1
7.127 1.880
2
12.967 2.515
3
2
1
5.453 1.061
0.810 0.035
0.769
2.157 0.180
0.333 0.577
0.904
2
12.267 1.710
0.780 0.040
0.911
3.163 0.385
7.667 2.517
0.974
4.209 0.336
3
27.333 5.160
0.840 0.020
0.980
8.840 0.429
33.333 11.846
0.977
12.579 1.134
1
4.540 2.072
0.840 0.090
0.784
1.977 0.200
1.000 1.000
0.907
2.212 0.304
2
8.477 0.300
0.820 0.017
0.912
2.890 0.174
3.667 1.528
0.970
3.570 0.350
3
24.333 5.652
0.830 0.040
0.974
7.850 0.725
25.000 8.888
0.980
10.870 1.143
of HMTstarch dispersions on temperature according to Arrhenius
model. Compared to native starch, the Ea values of HMT starch
were lower, indicating less temperature sensitivity of HMTstarch.
The Ea of HMT starch also increased with increasing in
concentration from 1 to 3% but the range was much broader
than that of native starch.
As seen in Table 3, generally, the coefficients of a and bof HMT
starch for both concentration-dependence models decreased as
temperature increased. Similar to native acorn starch, the exponential
model (R2 ¼ 0.983–0.998) also presented more acceptable results than
did the power law model (R2 ¼ 0.946–0.983).
As found in our previous study, HMT starch met the
requirements for the products experiencing severe conditions
processing;[23] nonetheless, its rheological behavior at steady
state should be demonstrated. The present study depicted that
HMT starch, like native starch, showed shear-thickening
behavior but with lower flow behavior index value; therefore,
change in viscosity with shear rate while pumping HMT-starch
solutions would be faster. Besides, dealing with this type of
modified starch seems to be easier as the range of changes
induced by temperature or concentration was not as broad as
that of native starch. Still, viscosity at a specified temperature or
concentration is much lower compared to native starch; however,
it could be beneficial as in some cases total solids should be high
without increasing in viscosity. On the other hand, as discussed
for native starch, the behavior of HMT starch was well-fitted by
the Casson model and for practically estimating the effects of
temperature and concentration on ηa,100, the Arrhenius model
and exponential model could be used, respectively.
3.3. Effect of Annealings
The shear-thinning behavior was also observed for ANN starch
with the flow behavior index in the range of 0.747–0.890
(Table 5). This range was between those of native and ANN
starches. Like HMT starch, there was not a particular trend in the
Starch/Stärke 2017, 1700156
flow behavior index as temperature or concentration increased.
The ηa,100 and kp values of ANN starch increased, as
concentration increased (Table 5). These values were also
between those of native and HMT starches. As discussed before
for HMT starch, it seems that the values of n, ηa,100, and kp of
ANN starch are mainly influenced by amylose leaching and
swelling power because these values were between those of
native and HMT starches.[23] The peak and final viscosity of ANN
starch were also between those of native and HMT starches.[23]
The values of ηa,100 and kp decreased as temperature increased.
The range of viscosity reduction (ηa,100) for 1–3% concentration
was between 0.868 and 27.278 mPa s which was between those of
HMT and native starches too.
The ηc values of ANN starch ranged from 2.170 (for 1%
concentration at 70 C) to 29.000 mPa s (for 3% concentration at
25 C) and the τ0c values were between 0.333 (for 1%
concentration at 70 C) and 459.333 mPa (for 3% concentration
at 25 C) (Table 5). These data were also between those of native
and HMTstarches. The ηc and τ0c values of ANN starch increased
at each temperature as concentration increased. The extent of
this increase was between those of native and HMT starches too.
Furthermore, at each concentration, as temperature increased,
the values of the ηc and τ0c decreased. Hoover and Vasanthan[44]
reported that ANN reduced the consistency coefficient of wheat
and lentil starch dispersions, but not as low as HMT did. The
consistency coefficient of potato starch dispersions increased on
ANN (in contrast to HMT). This increase was surprising because
swelling power and amylose leaching values had decreased on
ANN. They also reported that the flow behavior index increased
on ANN, but not as high as HMT did.
The range of 6.03–12.32 kJ mol1 with relatively high
determination coefficients (R2 ¼ 0.911–0.994) was obtained for
the Ea values of ηa,100 of ANN starch (Table 2). It shows that the
Arrhenius model described the dependence of the ηa,100 of ANN
starch dispersions on temperature. The Ea values of ANN starch
were lower than those of native starch (especially at 1%
concentration). Therefore, it demonstrates less sensitivity to
1700156 (6 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
Table 5. Effect of concentration and temperature of on the parameters of the power law and Casson models as well as apparent viscosity (ηa,100)
of ANN acorn starch.
Power law model
Temp. ( C)
25
40
55
70
n
Casson model
ηC (mPa s)
τ0C (mPa)
R2
0.870
2.563 0.040
3.000 1.000
0.954
3.142 0.086
0.805 0.035
0.967
7.675 0.516
34.500 6.364
0.981
11.262 0.261
178.400 41.328
0.760 0.010
0.860
29.000 9.067
459.333 77.674
0.933
56.521 14.068
6.410 1.268
0.820 0.036
0.840
2.457 0.117
0.333 0.577
0.931
2.562 0.083
2
22.033 1.550
0.807 0.006
0.950
6.220 0.035
19.333 5.033
0.985
8.594 0.350
3
145.267 56.409
0.747 0.038
0.894
20.500 4.095
393.000 154.981
0.945
42.282 10.755
1
6.167 1.613
0.807 0.051
0.800
2.267 0.126
0.333 0.577
0.916
2.368 0.105
2
11.967 1.550
0.890 0.035
0.979
5.710 0.446
6.667 2.309
0.989
6.990 0.243
3
92.767 25.672
0.797 0.047
0.857
17.100 1.039
321.333 85.886
0.929
35.050 3.530
1
4.550 1.408
0.840 0.056
0.791
2.170 0.157
0.333 0.577
0.908
2.274 0.302
2
11.200 0.849
0.870 0.028
0.965
4.795 0.417
6.500 0.707
0.989
5.973 0.398
3
69.400 17.874
0.820 0.036
0.894
15.967 0.321
202.333 71.396
0.941
29.242 3.159
Conc. (%)
kp (mPa s )
n ()
R
1
10.000 0.437
0.760 0.010
2
28.250 4.172
3
1
2
ηa,100 (mPa s)
ANN treatment, the viscosity and flow behavior of native starch
would not change considerably while it would be resistant to
severe conditions to some extent. Like native and HMT
starches, both Arrhenius and exponential models could be well
applied for predicting ηa,100 at different temperatures and
concentrations.
temperature changes. Although the Ea of ANN starch increased
with increasing in concentration, the range of Ea values was
broader than that of native starch (not as wide as that of HMT
starch).
Table 3 shows there was a reduction in the coefficients of a and
b of ANN starch for both concentration-dependent models and
the concentration dependence of the ηa,100 was better described
by the exponential model (R2 ¼ 0.998–0.999) than the power law
model (R2 ¼ 0.992–0.997).
ANN starch showed intermediate properties between native
and HMT starches and could be used in products exposing to
mild processing conditions.[23] However, the present study
showed the well-fitted rheological behavior of ANN starch
based on Casson model and confirmed that almost all the
steady state rheological properties of ANN starch were between
those of native and HMT starches, showing that by applying
3.4. Impact of Dual Hydrothermal Modification
Both dually modified starches (i.e., HMT-ANN and ANN-HMT)
presented shear-thinning behavior with the flow behavior index
in the range of 0.840–0.933 and 0.703–0.860, respectively (Tables
6 and 7). HMT-ANN starch showed the most flow behavior index
of all whilst ANN-HMT starch resembled the range of native,
HMT, and ANN starches. Like the other treatments, flow
Table 6. Effect of concentration and temperature of on the parameters of the power law and Casson models and apparent viscosity (ηa,100) of
HMT-ANN acorn starch.
Power law model
Temp. ( C)
25
40
55
70
Casson model
Conc. (%)
kp (mPa sn)
n ()
R2
ηC (mPa s)
τ0C (mPa)
R2
ηa,100 (mPa s)
1
5.003 0.927
0.867 0.025
0.860
2.723 0.235
0.333 0.577
0.946
2.841 0.434
2
8.710 0.392
0.907 0.012
0.976
4.877 0.170
2.333 0.577
0.994
5.571 0.206
3
31.750 2.475
0.875 0.021
0.940
12.150 0.636
51.000 1.414
0.968
17.638 0.850
1
3.930 0.161
0.880 0.010
0.818
2.443 0.116
1.000 0.000
0.917
2.766 0.123
2
7.767 0.476
0.873 0.015
0.952
3.66 0.145
2.333 0.577
0.987
4.264 0.095
3
20.933 3.722
0.913 0.015
0.964
10.967 0.907
19.000 8.544
0.976
14.009 1.751
1
3.950 0.645
0.853 0.025
0.794
2.180 0.085
0.667 0.577
0.909
2.384 0.128
2
7.610 0.934
0.840 0.017
0.915
2.903 0.142
3.333 3.215
0.968
3.507 0.175
3
15.000 2.081
0.933 0.006
0.980
9.300 0.920
6.667 2.887
0.985
10.928 1.343
1
3.157 0.367
0.880 0.035
0.797
2.017 0.146
0.667 0.578
0.910
2.217 0.318
2
6.120 2.023
0.867 0.040
0.897
2.813 0.064
2.333 4.041
0.952
3.129 0.483
3
15.333 3.137
0.897 0.021
0.964
7.740 0.662
8.000 4.359
0.983
9.368 1.174
Starch/Stärke 2017, 1700156
1700156 (7 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
Table 7. Effect of concentration and temperature of on the parameters of the power law and Casson models and apparent viscosity (ηa,100) of
ANN-HMT acorn starch.
Power law model
Temp. ( C)
25
40
55
70
n
Casson model
ηC (mPa s)
τ0C (mPa)
R2
ηa,100 (mPa s)
0.824
2.315 0.063
4.000 0.000
0.938
2.964 0.072
0.780 0.053
0.953
5.370 0.866
28.333 18.824
0.986
8.058 1.812
130.700 62.411
0.703 0.045
0.929
13.267 2.409
376.667 224.945
0.961
30.855 10.559
8.580 4.166
0.763 0.080
0.800
2.313 0.150
1.333 2.309
0.920
2.523 0.254
2
22.367 2.120
0.740 0.026
0.914
4.217 0.878
23.000 5.000
0.976
6.416 1.340
3
79.500 18.978
0.777 0.037
0.909
11.900 2.193
217.000 143.792
0.955
23.904 8.349
1
5.010 2.150
0.843 0.072
0.800
2.337 0.108
0.333 0.577
0.914
2.445 0.294
2
17.067 3.523
0.753 0.070
0.911
3.637 0.844
15.333 3.512
0.975
5.272 1.085
3
65.267 30.620
0.753 0.038
0.915
10.013 2.147
165.667 107.268
0.962
19.617 6.804
1
4.047 0.940
0.860 0.035
0.791
2.173 0.111
0.333 0.577
0.908
2.278 0.285
2
13.700 1.082
0.763 0.060
0.905
3.313 0.738
8.667 2.309
0.973
4.471 1.015
3
50.033 22.385
0.777 0.038
0.949
9.363 1.899
112.333 75.739
0.971
16.764 5.773
Conc. (%)
kp (mPa s )
n ()
R
1
11.600 0.849
0.715 0.021
2
24.167 11.288
3
1
behavior index of both dually modified starches did not follow
particular trends.
For both dully modified starches, the ηa,100 and kp values
increased as concentration increased (Tables 6 and 7). However,
for HMT-ANN starch, the second treatment increased these
parameters compared to HMTstarch. In contrast, for ANN-HMT
starch, the second treatment reduced those parameters
compared to ANN starch, showing that the second treatment
could negate the effects of the first one, as found for most
physico-chemical properties of dually modified acorn
starches.[23] Still, the impact of HMT on reducing these
parameters has been more considerable than that of ANN.
The swelling power and amylose leaching data of dually
modified starches were also between those of HMT and ANN
starches. Moreover, the peak, trough, and final viscosity of dually
modified starches were also between those of HMT and ANN
starches.[23] As observed before, increasing in temperature
decreased ηa,100 and kp values. The range of these reductions in
ηa,100 at 1–3% concentration were 0.625–8.270 and
0.686–14.091 mPa s for HMT-ANN and ANN-HMT starches,
respectively, which were mainly between those of single
modifications.
The ηc values of HMT-ANN and ANN-HMT starches ranged
from 2.017 (for 1% concentration at 70 C) to 12.150 mPa s (for 3%
concentration at 25 C) and 2.173 (for 1% concentration at 70 C) to
13.267 mPa s (for 3% concentration at 25 C), respectively. The τ0c
values of HMT-ANN and ANN-HMTstarches were between 0.333
(for 1% concentration at 25 C) and 51.000 mPa (for 3%
concentration at 25 C) and 0.333 (for 1% concentration at
75 C) and 376.667 mPa (for 3% concentration at 25 C),
respectively (Tables 6 and 7). These data were almost similar to
those of HMTstarch, showing that HMT induced more changes in
starch properties than did ANN. The values of ηc and τ0c at each
temperature generally increased as concentration increased. The
extent of this increase was more like that of HMT starch.
As seen in Table 2, the Ea values of HMT-ANN and ANN-HMT
starches were in the range of 5.04–12.20 kJ mol1, and
Starch/Stärke 2017, 1700156
2
4.70–11.54 kJ mol1 with relatively high determination coefficients (0.884–0.999). Like other starches in this study, the
Arrhenius model well described the dependence of ηa,100 of
dually modified starch dispersions on temperature. The Ea
values of dually modified starches were almost similar to those of
HMT starch (especially at the lowest concentration). The Ea
values of dually modified starches increased as concentration
increased from 1 to 3%; however, the range was broader than that
of native and ANN starches.
Like what observed for the other treatments, there was
generally a reduction in the coefficients of a and b of dually
modified starches for both models when temperature increased
and the exponential model (R2 ¼ 0.970–0.999) was better than
the power law model (R2 ¼ 0.919–0.990) at demonstrating the
concentration dependence of the ηa,100 (Table 3).
The noticeable result from our previous study was that the
second treatment could negate the induced effects of the first
one;[23] similarly, in the present study resembling results were
obtained about steady state rheological properties. In addition,
since most steady state features were more like to HMT starch, it
could be concluded that HMT induced more tangible changes.
Accordingly, if in a specific case, intermediate rheological
properties between HMT and ANN are required, dual
modifications will be quite handy.
4. Conclusion
Although both the power law and Casson models well described
the rheological behavior of the native and hydrothermally
modified starches, the Casson model showed better coefficients
of determination. The flow behavior of all starches was shearthinning and there were generally no particular trends in flow
behavior index as temperature or concentration increased. The
ηa,100 and kp of all starches increased with increasing in
concentration and decreased with increasing in temperature.
The same results were observed for the ηc and τ0c. The Ea of all
1700156 (8 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
www.advancedsciencenews.com
www.starch-journal.com
starches in the range of 25–70 C increased as concentration
increased, showing more sensitivity to temperature changes at
higher concentrations. However, the range of Ea was broader for
HMT-applied treatments, meaning that HMT could induce more
heterogeneity in starch. The effects of the concentration on the
ηa,100 in the temperature range of 25–70 C were better fitted by
the exponential model than the power law model for all starches.
The parameters of both models decreased as temperature
increased in all starches. The most effective factors influencing
the rheological parameters of starches were amylose leaching,
swelling power, and to some extent size parameters. Moreover,
the rheological data in this work were well confirmed by RVA
results carried out in our previous study. Generally, it could be
concluded that HMT induced the most changes in the steady
shear rheological properties probably due to its harsher
conditions and ANN had the lowest effects. Furthermore, the
properties of dually modified starches were mainly between
those of single modifications, showing that the changes induced
by the first modification could be negated by the second one.
Finally, the main practical result of the present study is that
generally hydrothermal modifications reduced the viscosity of
native starch as follows: HMT > HMT-ANN > ANN-HMT >
ANN. Therefore, it is possible to adjust the viscosity of a system
without changing in the quantity of native starch. Another point
is that hydrothermally modified starches are usually used to
reduce the breakdown of native starch; however, the viscosity of
native starch is generally reduced. The amounts of this reduction
for four types of hydrothermal modifications as well as the other
critical parameters of viscosity have reported here and they could
be used for various food formulations.
Abbreviations
ANN, annealing; HMT, heat-moisture treatment.
Conflict of Interest
The authors declare no conflict of interest.
Keywords
acorn starch, annealing, dual modification, modeling, rheology
Received: June 13, 2017
Revised: July 24, 2017
Published online:
[1] L. Toumi, R. Lumaret, Biochem. Syst. Ecol. 2001, 29, 799.
[2] A. Saffarzadeh, L. Vincze, J. Csapó, Acta Agraria Kaposváriensis 1999,
3, 59.
Starch/Stärke 2017, 1700156
[3] W. W. Wanio, E. B. Forbes, J. Agric. Res. 1941, 62, 627.
[4] L. H. Aee, K. N. Hie, K. Nishinari, Thermochim. Acta 1998, 322, 39.
[5] H. Fernald, A. Kinsey, Edible Wild Plants of Eastern North America.
Academic Press, Cornwall-on-Hudson, New York 1943.
[6] A. R. Hill, Economic Botany. Mc-Graw-Hill Book Co. Inc, New York
1937.
[7] M. Le
on-Camacho, I. Viera-Alcaide, I. M. Vicario, J. Am. Oil Chem.
Soc. 2004, 81, 447.
[8] H. Molavi, J. Keramat, B. Raisee, J. Food Biosci. Technol. 2015, 5, 53.
[9] S. Rakić, D. Povrenović, V. Tesević, M. Simić, R. Maletić, J. Food Eng.
2006, 74, 416.
[10] D. Tejerina, S. García-Torres, M. Cabeza de Vaca, F. M. Vázquez,
Food Chem. 2011, 124, 997.
[11] P. R. Correia, M. L. Beir~ao-da-Costa, Starch/Stärke 2010, 62, 421.
[12] D. G. Stevenson, J. Jane, G. E. Inglett, Starch/Stärke 2006, 58, 553.
[13] S. H. Hosseini-Parvar, L. Matio-Merino, K. K. T. Goh, S. M. A. Razavi,
S. A. Mortazavi, J. Food Eng. 2010, 101, 236.
[14] A. Koocheki, S. M. A. Razavi, Food Biophys. 2009, 4, 353.
[15] S. M. A. Razavi, H. Kardzhiyan, Food Hydrocolloids 2009, 23, 908.
[16] A. R. Yousefi, S. M. A. Razavi, J. Food Process. Eng. 2016, 39, 31.
[17] H. J. Chung, R. Hoover, Q. Liu, Int. J. Biol. Macromol. 2009, 44, 203.
[18] H. Jacobs, J. A. Delcour, J. Agric. Food Chem. 1998, 46, 2895.
[19] R. F. Tester, S. J. J. Debon, Int. J. Biol. Macromol. 2000, 27, 1.
[20] L. Jayakody, R. Hoover, Carbohydr. Polym. 2008, 74, 691.
[21] H. J. Chung, Q. Liu, R. Hoover, Carbohydr. Polym. 2009, 75, 436.
[22] H. Molavi, S. Behfar, M. A. Shariati, M. Kaviani, S. Atarod, Food Sci.
2015, 4, 456.
[23] H. Molavi, S. M. A. Razavi, R. Farhoosh, Food Chem. Unpublished.
[24] P. R. Correia, M. L. Beir~ao-da-Costa, Food Bioprod. Process. 2012, 90,
309.
[25] W. J. Lim, Y. T. Liang, P. A. Seib, C. S. Rao, Cereal Chem. 1992, 69, 233.
[26] R. Hoover, T. Vasanthan, Carbohydr. Res. 1994, 252, 33.
[27] H. J. Chung, Q. Liu, R. Hoover, Food Res. Int. 2010, 43, 501.
[28] M. A. Rao, in Rheology of Fluid and Semisolid Foods (Ed: M. A. Rao),
Springer, New York 2007.
[29] W. W. Kim, B. Yoo, Int. J. Food Sci. Technol. 2009, 44, 503.
[30] H. Cornell, in Starch in Food (Ed: A.-C. Eliasson), Woodhead
Publishing Limited, Cambridge, UK 2004, Ch. 7, pp. 211.
[31] P. N. Bhandari, R. S. Singhal, D. D. Kale, Carbohydr. Polym. 2002, 47,
365.
[32] S. D. Holdsworth, J. Texture Stud. 1971, 2, 393.
[33] I. M. Nurul, B. M. N. M. Azemi, D. M. A. Manan, Food Chem. 1999,
64, 501.
[34] M. Irani, S. M. A. Razavi, E.-S. M. Abdel-Aal, M. Taghizadeh, Starch/
Stärke 2016, 68, 1500348.
[35] C. K. Rha, Food Technol. 1978, 32, 77.
[36] D. T. Constenla, J. E. Lozanno, G. H. Crapiste, J. Food Sci. 1989, 54,
663.
[37] H.-M. Choi, B. Yoo, Starch/Stärke 2008, 60, 263.
[38] D. Sun, B. Yoo, LWT – Food Sci. Technol. 2015, 64, 205.
[39] D. J. Thomas, W. A. Atwell, Starches. AACC International Inc, St. Paul,
MN, USA 1997, Ch. 1, pp 1.
[40] R. Moreira, F. Chenlo, M. D. Torres, J. Glazer, J. Food Eng. 2012, 112,
94.
[41] D. Kuakpetoon, Y. J. Wang, Carbohydr. Res. 2007, 342, 2253.
[42] S. Y. Chun, B. Yoo, Starch/Stärke 2007, 59, 334.
[43] K. J. Shon, B. Yoo, Starch/Stärke 2006, 58, 177.
[44] R. Hoover, T. Vasanthan, J. Food Biochem. 1994, 18, 67.
1700156 (9 of 9)
© 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Документ
Категория
Без категории
Просмотров
1
Размер файла
296 Кб
Теги
201700156, star
1/--страниц
Пожаловаться на содержимое документа