ArticlePDF Available

Effects of pseudocereals, legumes and inulin addition on selected nutritional properties and glycemic index of whole grain wheat-based biscuits



Based on the nutritionists‘ opinion that diet may have a preventive and protective role in many diseases, the possibilities of development of biscuits with lower glycemic index (GI) as functional cereal-based products were examined in this work. Results showed that, by substitution of 30% of white wheat flour with selected pseudocereals (buckwheat or amaranth flour) and legumes (soya or carob flour), it was possible to achieve better macronutritive quality of biscuits. Incorporation of selected flours resulted in a decrease of in vitro starch digestibility in terms of significant decrease of rapidly available glucose (9.6–47.6%), and rapidly digestible starch (9.8–50.4%). A significant increase in the resistant starch content was achieved by the implementation of pseudocereals (43.5–56.1%). Control biscuits, biscuits with added saccharose, and biscuits with buckwheat flour and without inulin, had medium GI (58.7–66.9), while samples with amaranth, soya or carob flour had low GI (44.9–52.5). None of the investigated biscuits had high GI. A very good correlation between the results obtained in vitro and GI values were determined indicating that the formulation of biscuits with lower starch digestibility represented a good approach in lowering GI of biscuits, and therefore increasing its functional properties.
Journal of Food and Nutrition Research (ISSN 1336-8672) Vol. 53, 2014, No. 2, pp. 152–161
152 © 2014 Národné poľnohospodárske a potravinárske centrum (Slovakia)
Biscuits are a very popular snack food used
worldwide across all population groups [1]. They
usually contain a high proportion of lipids and sac-
charose to achieve more appealing flavour, which
classifies them as foods whose regular consump-
tion represents a risk factor for obesity, and thus
an increased risk of developing type 2 diabetes,
high cholesterol and coronary heart disease [2]. In
the modern world dominated by highly processed
and nutritionally poor foods, there are efforts to
complement the diet with valuable nutrients by
so called functional products. Taking into account
trends in the food industry, as well as the recom-
mendations of nutritionists who are increasingly
pointing out at preventive and protective role of
diet in many diseases, the efforts of food technolo-
gists are focused in recent years to preparing bis-
cuits with functional properties. Generally, func-
tional foods are challenging the food industry in
technological as well as in economic terms since
studies have shown that most consumers rarely
waive taste for health and it is therefore impor-
tant to develop functional food products with re-
tained traditional organoleptic characteristics [3].
Hence, many studies have focused on the creation
of biscuits with enhanced nutritional characteris-
tics without disruption the biscuit quality, where-
by a number of improvements are based on the
replacement of certain amount of refined wheat
flour with various raw materials of high nutritional
value such as soya, buckwheat or amaranth flour
Buckwheat is a rich source of proteins, fibres,
antioxidants, minerals and starch that contains
substantial amounts of resistant starch, which may
contribute to lowering of glycemic index (GI) of
food [5]. Moreover, in the recent study [7] a de-
crease in GI was reported for bread made from
a mixture of buckwheat and wheat flours. This was
due to binding of fatty acids, rutin and epicate-
Effects of pseudocereals, legumes and inulin addition
on selected nutritional properties and glycemic index
of whole grain wheat-based biscuits
Based on the nutritionists‘ opinion that diet may have a preventive and protective role in many diseases, the possibili-
ties of development of biscuits with lower glycemic index (GI) as functional cereal-based products were examined in
this work. Results showed that, by substitution of 30% of white wheat flour with selected pseudocereals (buckwheat or
amaranth flour) and legumes (soya or carob flour), it was possible to achieve better macronutritive quality of biscuits.
Incorporation of selected flours resulted in a decrease of in vitro starch digestibility in terms of significant decrease of
rapidly available glucose (9.6–47.6%), and rapidly digestible starch (9.8–50.4%). A significant increase in the resist-
ant starch content was achieved by the implementation of pseudocereals (43.5–56.1%). Control biscuits, biscuits with
added saccharose, and biscuits with buckwheat flour and without inulin, had medium GI (58.7–66.9), while samples
with amaranth, soya or carob flour had low GI (44.9–52.5). None of the investigated biscuits had high GI. A very good
correlation between the results obtained in vitro and GI values were determined indicating that the formulation of
biscuits with lower starch digestibility represented a good approach in lowering GI of biscuits, and therefore increasing
its functional properties.
in vitro starch digestibility; glycemic index; biscuits
Lovorka Vujić, Dubravka Vitali Čepo, Blaženka Šebečić, Irena Vedrina Dragojević, Department of Food Chemistry, Faculty
of Pharmacy and Biochemistry, University of Zagreb, Ante Kovačića 1, 10000 Zagreb, Croatia.
Correspondence author:
Lovorka Vujić, tel.: +385 1 4612690, e-mail:
Nutritional properties and glycemic index of whole grain wheat based biscuits
final product in terms of increasing the contents of
dietary fibre, slowly digestible and resistant starch,
as well as proteins. The present work represents
an attempt to decrease the GI of this frequently
consumed snack.
Preparation of biscuits
Seven types of biscuits were prepared under
laboratory conditions in Technological develop-
ment department in Kraš, confectionary factory in
Zagreb, Croatia, in three series, in order to ensure
the reliability of the obtained data. For biscuits
preparation, whole grain and white wheat flour
(Farina, Granolio, Zagreb, Croatia) were used as
basic flours. Buckwheat flour (Do-It, Barneveld,
Netherland), amaranth flour (Do-It), full fat soya
flour (Biovega, Zagreb, Croatia) and carob flour
(Šafram, Zagreb, Croatia) as substitute flours,
were incorporated into biscuit by replacing the
equivalent amount of white wheat flour in the bis-
cuit formulation. All flours were purchased at the
local market in Croatia.
Control biscuits were prepared with 949 g
whole grain wheat flour, 633 g white wheat flour,
274 g vegetable fat without trans fatty acids (K3-Z,
Zvijezda, Zagreb, Croatia), 259 g inulin (Beneo,
Tienen, Belgium), 87 g skimmed milk powder
(Lactoprot, Kaltenkirchen, Germany), 20 g ammo-
nium bicarbonate, 20 g salt (Solana Pag, Pag,
Croatia), 7 g vanilla flavour (Symrise, Holz minden,
Germany), 249 g isomalt (Beneo) and 0.3 g sucra-
lose (McNeil Nutritionals, Fort Washing ton, Penn-
sylvania, USA).
In four biscuit formulations, a definite amount
(480 g) of white wheat flour was replaced by dif-
ferent above mentioned substitute flour; one for-
mulation was prepared using powdered saccharose
(249 g) instead of saccharose substitute (isomalt)
and artificial sweetener (sucralose), and one was
prepared without inulin. Composition of the ex-
perimental biscuits is presented in Tab. 1.
Other ingredients were added in the same
amounts as in control biscuits. Water was added
as needed depending on the type of flour used.
Resulting dough was laminated on the machine
roller up to 0.5 cm thickness and followed by hand
shaping of biscuits using moulds 4 cm in diameter.
Biscuits were baked at 175 °C for 17–19 min, de-
pending on the raw material used and the amount
of water added. After baking, biscuits were cooled
and, before mincing, samples for GI determina-
tion were separated.
chin-dimethylhallate, contained in buckwheat, to
wheat flour starch.
Amaranth is another pseudocereal with pro-
tein content higher than wheat, with well balanced
amino acid composition. It is also a rich source of
dietary fibre, lipids and minerals [8]. According
to study of KIM et al. [9], amaranth grain could
be helpful in reduction of elevated serum glucose
levels and preventing diabetic complications.
Legumes (soya and carob) are low glycemic
foods, being excellent sources of dietary fibre, va-
riety of micronutrients and phytochemicals. Soya
contains high quality proteins as well as isofla-
vones with well documented health benefits [10].
Carob has high content of carbohydrates, appreci-
able content of proteins, low content of lipids, and
has antioxidant properties due to the high content
of condensed tannins [11].
Regarding the growing epidemic of obesity and
type 2 diabetes worldwide, more attention is paid
to creating lower GI products, since numerous
studies have demonstrated positive effects of low
glycemic diet on health. Hence, MARAGONI and
POLI [12] added specific pro prietary fibre mix to
the biscuit formulation thus significantly reducing
GI. JENKINS et al. [13] concluded that highly vis-
cous fibre blend (PGX; InovoBiologic, Calgary,
Canada) incorporated to a starchy snack (biscuit)
reduced the GI by 74% in healthy, and by 63% in
diabetic consumers.
Starch can be found in various physical and
chemical forms in foods, which affect the rate and
the extent of digestion and, consequently, its nu-
tritional and health properties. When the rate of
starch digestion is decreased, postprandial glucose
and insulin responses are reduced or delayed [14].
Diets rich in slowly digested carbohydrates may
protect against chronic disorders and/or diseases
such as central obesity, hyperlipidemia and cancer
[15]. Various factors affect starch digestibility such
as nature of starch, protein and lipid interactions,
presence of antinutrients and enzyme inhibitors,
as well as food processing conditions [16]. This
suggests that, by careful selection of raw materials,
these parameters can be altered and also, conse-
quently, the GI of the final product. Additionally,
glycemia can be further reduced by replacing sac-
charose with indigestible carbohydrates such as
sugar alcohols [17].
The goal of this work was to examine the pos-
sibilities of improving the traditional biscuits for-
mulation by introduction of novel raw materials,
such as pseudocereals, legumes or inulin. The
proposed modifications are aimed primarily to re-
duce GI, while maintaining or enhancing the nu-
tritional quality and functional properties of the
Vujić, L. et al. J. Food Nutr. Res., 53, 2014, pp. 152–161
Chemical analysis of biscuits
Moisture content was determined according to
AACC 44-15A method, ash content according to
AACC 08-01, proteins according to AACC 46-12
[18] using multiplying the nitrogen content by
factor 6.25, and total lipids according to AOAC
920.39C method [19]. Total dietary fibre (TDF)
content was assessed by enzymatic–gravimetric
AOAC 991.43 method as the sum of the soluble
(SDF) and insoluble dietary fibre (IDF) fractions
[19]. The protein, ash, lipid and moisture contents
were subtracted from the total weight and the dif-
ference was considered as total carbohydrates.
Available carbohydrates were calculated as a dif-
ference between total carbohydrates and the sum
of total dietary fibre, isomalt and inulin.
In order to calculate the energy value of the in-
vestigated biscuits, Atwater general factor system
was used [20]. Conversion factors that were used
were 17 kJ·g-1 for proteins and available carbohy-
drates, 37 kJ·g-1 for lipids and 8 kJ·g-1 for dietary
fibre. Energy values used for isomalt and inulin
were 9 kJ·g-1 [21] and 6.3 kJ·g-1 [22], respectively.
Energy value (EV) in kilojoules was calculated
according to the following equation:
where P is content of proteins, L is content of
lipids, avCHO is content of available carbohy-
drates, F is content of fibre, IS is content of iso-
malt and IN is content of inulin (all in grams).
In vitro protein and starch digestibility
In vitro protein digestibility of the biscuits
was determined by enzymatic method with pep-
sin (P7000, Sigma-Aldrich, Steinham, Germany)
and pancreatin (P1750, Sigma-Aldrich) according
to KUMAGAI et al. [23]. In vitro starch digestibil-
ity was determined according to the procedure of
ENGLYST et al. [14]. The analysis was carried out
under controlled enzymatic hydrolysis with inver-
tase (I4504, Sigma-Aldrich), pancreatin (P7545,
Sigma-Aldrich) and amyloglucosidase (A3042,
Sigma-Aldrich) at 37 °C in capped tubes immersed
in a shaker water bath, followed by measurement
of released glucose by GOD-PAP (glucose oxi-
dase/peroxidase) method [24] using a diagnostic
kit (Dijag nostika, Sisak, Croatia). The value G20
(rapid ly available glucose) was obtained by meas-
uring the release of glucose after 20 min of enzy-
matic incubation, while G120 was estimated after
further 100 min of incubation.
The total glucose value (TG) was obtained by
treating the sample with heat-stable -amylase
(A3306, Sigma-Aldrich) in boiling water, followed
by immediate cooling, treatment with potassium
hydroxide (7 mol·l-1) at 0 °C, and followed by com-
plete enzymatic hydrolysis with amyloglucosidase.
Free glucose (FG) was determined by treat-
ing the sample with invertase in acetate buffer at
100 °C (water bath) for 30 min. Simultaneous tests
were run in the same manner with standard glu-
cose and blank.
Rapidly digestible starch (RDS), slowly digest-
ible starch (SDS), resistant starch (RS) and total
starch (TS) were calculated according to following
equations [14]:
Glycemic index determination
Ten healthy volunteers (five men and five
women) aged from 21 to 43, with an average body
mass index of (22.36 ± 1.12) kg·m-2, were included
in GI testing. The volunteers were non-smokers
Tab. 1. Composition of the experimental biscuits.
Whole grain
wheat flour
wheat flour Raw material Inulin Isomalt/Sucralose Saccharose
Control sample 949 633 259 249/0.3
With saccharose 949 633 259 249
With buckwheat flour 949 153 480 (buckwheat flour) 259 249/0.3
With amaranth flour 949 153 480 (amaranth flour) 259 249/0.3
With carob flour 949 153 480 (carob flour) 259 249/0.3
With soya flour 949 153 480 (soya flour) 259 249/0.3
Without inulin 949 633 249/0.3
Nutritional properties and glycemic index of whole grain wheat based biscuits
and had no history of metabolic disease, as deter-
mined by a questionnaire prior to recruitment. All
subjects gave written consent prior to inclusion in
the study after being given a detailed description
of the study protocol and had opportunity to ask
questions. The participants were asked to main-
tain standard diet and to refrain from heavy physi-
cal activity as well as consumption of alcoholic and
caffeinated drinks the day prior to the test. The
study protocol was approved by the Ethical Com-
mittee of the Croatian Institute for Transfusion
Medicine and Committee on Ethics of the Experi-
mental Work of the Faculty of Pharmacy and Bio-
chemistry in Zagreb, Croatia.
The protocol procedure was in agreement with
the recommendations of FAO/WHO [25] and
BROUNS et al. [17]. Each participant tested seven
different types of biscuits once in a random order,
while the reference food was tested twice. Tests
were performed during morning after a 12 h over-
night fast, with a gap of at least two days between
measurements. Each volunteer ate a biscuit por-
tion containing 50 g of available carbohydrates
within 10 min with 250 ml of tap water. Reference
food (anhydrous glucose) was prepared by dissolv-
ing 50 g of pure glucose in 250 ml of water. Ca-
pillary finger-prick blood samples were taken from
participants at 0, 15, 30, 45, 60, 90 and 120 min
after the beginning of the test, or after reference
food intake (time 0 min). The blood glucose con-
centration was measured using Contour automatic
glucose meter (Bayer HealthCare, Leverkusen,
Germany), whose accuracy was verified using high,
low and normal test solutions (Bayer Consumer
Care, Basel, Switzerland).
Statistical analysis
One-way ANOVA was used to investigate dif-
ferences between three examined series of biscuits.
Since no significant differences were observed
(p > 0.05), all results were presented as means of
series of biscuits ± standard deviation. Depending
on the applied method, analyses were conducted
in duplicates or triplicates within one series of bis-
cuits. One-way ANOVA and post-hoc Bonferroni
test were applied to study the differences between
different biscuit formulations, the significance
being determined at the level of p < 0.05.
For GI calculation, the incremental area under
curve (iAUC) of blood glucose response, ignoring
the area beneath the baseline, was calculated geo-
metrically [25]. GI of biscuits was calculated as the
ratio between mean iAUC for the biscuit tested
and mean iAUC of the reference food (glucose so-
lution). The GI results are expressed as mean ±
standard error (SEM). Correlation coefficients
(r) between GI, different starch and dietary fibre
fractions as well as protein and lipid contents were
also calculated.
All statistical analyses were performed using
GraphPad Prism 3 software (GraphPad Software,
San Diego, California, USA).
Macronutritive and nutritional compositions
of investigated biscuits are shown in Tab. 2. It can
be seen from presented data that the addition of
flours of different origins to the control biscuits re-
sulted in significant improvement of certain nutri-
tive parameters.
Total protein and lipid contents were the high-
est in biscuits enriched with soya flour, as was
expected, since soya flour is rich in these com-
ponents. Although soybeans are high in lipids,
which are traditionally an undesirable ingredient
in human diet, majority of them are unsaturated
fatty acids with beneficial health effects [10]. Total
dietary fibre content was significantly increased in
biscuits enriched with buckwheat, amaranth and
soya flours, with the strongest effect achieved by
the addition of carob flour (an increase of 96%
compared to the control biscuits) solely as the re-
sult of high insoluble fibre content. Since all inves-
tigated biscuits contained more than 6 g of fibre
per 100 g dry matter, they can be classified as food
rich in fibre according to EU regulation 1924/2006
In vitro protein digestibility is an important
factor when assessing the nutritional quality of
a food product. The obtained results showed that
addition of all substitute flours to the control bis-
cuits decreased protein digestibility of the final
product, which is consistent with literature data
for products of similar type [27, 28]. The observed
results may be explained by the fact that high
levels of dietary fibre (biscuits with carob flour)
had a negative effect on protein digestibility due
to possible complex formation between the fibre
and the proteins, as reported BILGIÇLI et al. [29],
or by high levels of anti-nutritive components such
as trypsin inhibitor present in soybean [30] and
tannins present in carob [11]. Buckwheat contains
antinutrients such as the protease inhibitor and
tannins [31].
Bearing in mind that the nature of starch and
consequently its digestibility has a fundamental
role in the rate of its absorption, an attempt to re-
duce starch digestibility and, consequently, glucose
response in vivo was made by introducing differ-
ent raw materials to biscuit formulation. As pre-
Vujić, L. et al. J. Food Nutr. Res., 53, 2014, pp. 152–161
sented in Tab. 3, significant differences were found
regarding the contents of rapidly available glucose
(RAG), RDS, SDS and TS.
It is noticeable that incorporation of substitute
flours resulted in a decrease of RAG and RDS con-
tent in relation to control sample, and the strong-
est impact was achieved by addition of amaranth
flour (24.9% and 26.6%, respectively), carob flour
(35.9% and 50.4%, respectively) and soya flour
(47.6% and 50.1%, respectively). Obtained data
are consistent with the fact that legumes (soya and
carob) have a higher amylose/amylopectin ratio
in starch granules compared to cereals, and are
therefore less susceptible to amylolysis. This is be-
cause amylose molecules contain more hydrogen
bonds making them less accessible to digestive
enzymes action than amylopectin mole cules with
a branchy structure [32]. Additionally, carob and
soya contain high amounts of dietary fibre, which
may affect starch digestibility. Furthermore, as
previous ly noted, soya contains high protein and
lipid amounts that have a protective effect against
amylolytic activity, diminishing the level of enzy-
matic hydrolysis by reducing the available surface
area through blocking the adsorption sites [33].
Also, carob is rich in tannins with antinutritive
effect [11]. Although amaranth contains relatively
high amounts of starch, small size of starch gran-
ules and low amylose content [8], i.e. factors that
increase starch digestibility, amaranth flour supple-
mentation of the control formulation resulted in its
reduction. The obtained results can be explained
by the relatively high protein, lipid and dietary fi-
bre contents, as well as low level milling used for
amaranth flour.
Statistically significant increase in RAG content
in relation to the control sample was determined
in samples with saccharose (17.4%) and without
inulin (22.0%). In this concern it should be noted
that inulin removal from the control formulation
had a more significant influence on the above men-
tioned parameter than the addition of saccharose.
Also, a significant increase in RDS values was ob-
served only in biscuit without inulin (25.4%), partly
as a result of a higher total starch content.
SDS is the starch fraction completely digested
in the small intestine but, as opposed to RAG, at
a lower rate. Modification of the control formu-
lation resulted in significantly reduced SDS con-
tent in all samples enriched with substitute flours,
partially due to the reduction of the total starch
content. Indeed, the greatest impact on SDS de-
crease was found in biscuits supplemented with
carob flour (19.8%) and with soya flour (25.0%),
which can be explained by the significant reduc-
tion in TS content in those samples (37.9% and
Tab. 2. Chemical and nutritional properties of biscuits.
Sample Proteins
dietary fibre
dietary fibre
dietary fibre
In vitro protein
Control sample 9.69 ± 0.13 a12.36 ± 0.18 a1.84 ± 0.01 a76.11 ± 0.06 a8.07 ± 0.40 a4.38 ± 0.14 a3.69 ± 0.27 ae 79.38 ± 2.43 a1 644
With saccharose 9.50 ± 0.06 a12.39 ± 0.19 a1.75 ± 0.04 b76.36 ± 0.28 ad 7.53 ± 0.29 b4.01 ± 0.10 a3.52 ± 0.25 a78.26 ± 3.78 a1 732
With buckwheat flour 10.24 ± 0.09
b12.25 ± 0.17 a2.06 ± 0.03 c75.45 ± 0.23 b9.81 ± 0.32 c5.27 ± 0.32 b4.54 ± 0.13 b69.70 ± 2.33 b1 623
With amaranth flour 10.97 ± 0.19
c13.54 ± 0.58 b2.30 ± 0.06 d73.19 ± 0.49 c9.95 ± 0.16 c5.89 ± 0.05 c4.06 ± 0.17 c72.50 ± 3.37 bd 1 648
With carob flour 9.04 ± 0.08
d11.96 ± 0.27 a2.26 ± 0.01 d76.74 ± 0.33 d15.82 ± 0.56 d12.86 ± 0.53 d2.96 ± 0.27 d51.97 ± 3.33 c1 564
With soya flour 16.66 ± 0.19
b17.61 ± 0.61 c2.80 ± 0.07 e62.92 ± 0.75 e11.31 ± 0.13 e7.35 ± 0.04 e3.96 ± 0.14 ec 70.00 ± 3.47 b1 711
Without inulin 10.44 ± 0.03 e13.05 ± 0.28 b 1.81 ± 0.01
ab 74.70 ± 0.25 f6.37 ± 0.41 f4.80 ± 0.21 f1.57 ± 0.20 f75.57 ± 1.74 ad 1 744
The results are reported as means of three investigated series of biscuits ± standard deviation, per 100 g on dry basis. Data in the same column marked with the same letter are the part of
the same statistical group (p > 0.05).
Nutritional properties and glycemic index of whole grain wheat based biscuits
39.5%, respec tively). In biscuits supplemented
with pseudo cereals (buckwheat and amaranth
flours), SDS decrease occurred partially due to
the increase in RS content. This is consistent with
the results of RAGAEE et al. [34], who determined
in vitro starch digestibility in bread with 30% of
white wheat flour replaced with various whole-
grain flours.
In comparison to other food rich in starch, in-
cluding biscuits [35, 36], the investigated samples
had lower RAG and RDS contents, and higher
SDS and RS contents, as a result of several fac-
tors. Namely, the basis of formulation of the in-
vestigated biscuits was whole grain wheat flour,
i.e. low grade milled flour, where starch granules
are trapped within the cell wall, which slows down
their degradation. Additionally, degradation of the
starch granules by grinding increases the sensitiv-
ity to enzymatic degradation [37]. The same effect
has extended milling since smaller particles have
a larger surface area available for amylolytic ac-
tivity [38]. Another fact that might contribute to
this effect was the high dietary fibre content and
baking under low moisture conditions, which re-
duce starch gelatinization resulting in partially
intact starch granules that are less sensitive to the
amylolytic enzymes [36].
Glycemic index of biscuits
The primary aim of this study was to examine
the impact of introducing different raw materials
on the postpradial glycemia of whole grain wheat-
based biscuits. The obtained results show that the
highest glucose response in volunteers was ob-
served 30–45 min after consumption of the test
food (Fig. 1).
The highest increase in blood glucose concen-
tration was observed after consumption of biscuits
Tab. 3. Content of different carbohydrates fractions in experimental biscuits.
Rapidly available
Rapidly digestible
Slowly digestible
starch Resistant starch Total starch
Control sample 289.20 ± 4.37
a250.72 ± 4.07 a157.46 ± 9.70 a35.56 ± 8.04 a443.74 ± 18.69 a
With saccharose 339.60 ± 3.99
b251.74 ± 4.16 a162.88 ± 10.26 a34.73 ± 6.72 ad 449.34 ± 12.06 a
With buckwheat flour 261.38 ± 10.78
c226.22 ± 9.69 b132.24 ± 11.66 bc 55.51 ± 1.40 b413.97 ± 4.02 b
With amaranth flour 217.32 ± 4.29
d184.12 ± 3.80 c137.81 ± 8.67 bd 51.02 ± 0.79 b372.95 ± 4.57 c
With carob flour 185.47 ± 3.57
e124.37 ± 3.72 d126.28 ± 9.34 bc 25.10 ± 2.25 c275.75 ± 12.14 d
With soya flour 151.68 ± 5.25
f125.16 ± 4.63 d118.08 ± 13.42 c25.08 ± 5.54 c268.32 ± 9.35 d
Without inulin 352.71 ± 9.27
g314.25 ± 8.30 e151.10 ± 10.63 ad 27.35 ± 6.86 dc 492.70 ± 11.02 e
The results are reported as means of three investigated series of biscuits ± standard deviation. Data in the same column marked
with the same letter are the part of the same statistical group (p > 0.05); values are expressed per kilogram on dry basis.
Fig. 1. Glycemic response to biscuits.
Values are expressed as mean ± standard error (n = 10).
Vujić, L. et al. J. Food Nutr. Res., 53, 2014, pp. 152–161
with saccharose (after 30 min) although, compared
to the reference sample, this difference was not
statistically significant (p > 0.05). Consumption of
biscuits with soya flour resulted in the lowest levels
of blood glucose, which proved to be statistically
significant compared to the sample with saccha-
rose (after 30 min and 45 min), and statistically
significant in comparison with the biscuit without
inulin (after 45 min). Given that food can be clas-
sified according to its glycemic effect [39] as those
that have a high ( 70), medium (56–69) and low
GI ( 55) compared to the standard (glucose solu-
tion, GI = 100), the investigated samples were cat-
egorized in the following way: control biscuits, bis-
cuits with saccharose, buckwheat flour and without
inulin were medium GI products, while biscuits
prepared with amaranth, soya or carob flours
had low GI. None of the investigated biscuits had
high GI. Although a wide range of GI values was
observed for the investigated samples (Tab. 4),
the differences were not statistically significant
(p > 0.05) due to a large dissipation among the
results. The obtained results indicate that by intro-
ducing pseudocereals (buckwheat and amaranth
flour) and legumes (carob and soya flour) instead
of white wheat flour, a decrease in blood glucose
response can be achieved.
In order to establish the relationship between
in vitro starch digestibility and in vivo glucose re-
sponse after consumption of the investigated bis-
cuits, GI values were correlated with the amount
of starch fractions contained in 50 g of available
carbohydrates, as the amount containing servings
used to determine GI (Tab. 4). Although in vitro
methods cannot completely imitate in vivo condi-
tions, such as degree of gastric emptying or the
influence of intestinal hormones, a very good
correlation between the results obtained in vitro
method and GI values was determined (Tab. 5).
Correlation between GI and RAG values
proved to be the most significant (p = 0.01)
among the tested starch fractions, which is con-
sistent with literature [14]. Additionally, there
was a strong negative correlation between the
SDS and GI values (p = 0.04) indicating a reduc-
ing effect of SDS on in vivo glucose response.
The obtained results suggest that creating low
RAG/RDS and high SDS foods, is an effective ap-
proach for lowering GI. The analysis of the rela-
tionship between macro nutrient content and GI
values (Tab. 5) showed a significant negative cor-
relation between the protein content (p = 0.08)
and lipids (p = 0.05), which confirms the above
mentioned allegations about the impact of these
components on the digestibility of starch and, con-
sequently, GI. These findings are in accordance
with the results of GARSETTI et al. [40] who inves-
tigated the relationship between GI of plain sweet
biscuits and in vitro starch digestibility, and found
similar negative correlation between GI and pro-
tein and lipid contents, as well as between GI and
SDS content. Also, we established a very strong
negative correlation between GI and TDF con-
tent (r = –0.95; p = 0.00) and its fractions (SDF,
r = –0.73; p = 0.07 and IDF, r = –0.87; p = 0.01).
Similar results were obtained by WOLEVER [41],
who examin ed the relationship between dietary
fibre content and GI of different foods and estab-
lished a significant negative relationship with total
fibre and its insoluble fraction (p < 0.05), but not
with the soluble fibre content. Correlation with
SDF observed in this study can be explained by
the fact that the investigated samples were pro-
duced under strictly controlled conditions, had
Tab. 4. Portion size, rapidly available glucose, starch fractions and glycemic index of the examined biscuits.
starch Total starch Glycemic
Control sample 105.0 30.4 26.3 16.5 3.7 46.6 60.1 ± 4.8
With saccharose 85.6 29.1 21.5 13.9 3.0 38.5 65.8 ± 5.6
With buckwheat flour 110.5 28.9 25.0 14.6 6.1 45.8 58.7 ± 6.2
With amaranth flour 116.7 25.4 21.5 16.1 6.0 43.5 52.5 ± 5.9
With carob flour 123.4 22.9 15.3 15.6 3.1 34.0 46.8 ± 6.0
With soy flour 160.2 24.3 20.1 18.9 4.0 43.0 44.9 ± 5.3
Without inulin 93.8 33.1 29.5 14.2 2.6 46.2 66.9 ± 4.6
Rapidly available glucose and starch fractions are expressed as grams per serving containing 50 g of available carbohydrates.
Glycemic index is expressed as mean ± standard error (n = 10), data in the column marked with the same letter are the part
of the same statistical group (p > 0.05);
Nutritional properties and glycemic index of whole grain wheat based biscuits
similar formulation and same processing condi-
tions. Therefore, the sole impact of SDF could be
JENKINS et al. [42] examined the interac-
tion between starch and proteins in whole grain
wheat bread and found that the removal of gluten
from wheat flour increased the amylolytic diges-
tion in vitro and increased the in vivo gly cemic
response. This was explained by formation of
a gluten-protein complex that interfered with the
amylase action. Similar results were obtained by
BERTI et al. [43] who examined the same para-
meters in pasta and bread, with and without glu-
ten. These authors also observed effects of the
technological processing on in vitro starch digest-
ibility. On the other hand, PACKER et al. [44] ex-
plained the phenomenon solely by differences in
the manu facturing process.
In our study, gluten was not removed but glu-
ten-free flours were added at a rate of 30% in-
stead of refined white wheat flour. In spite of this,
no negative effects of dilution of gluten on the
observed parameters were noticed. Moreover, the
introduction of selected flours to control formula-
tion resulted in a decrease of in vitro starch digest-
ibility, as well as in vivo glucose response with the
highest impact observed for biscuits enriched with
soya flour (by 25.3% lower GI values compared to
the control sample). These findings are consistent
with the results of BLAIR et al. [45] suggesting that
food based on soya has low or medium GI values,
and is suitable for the regulation of blood glucose
and insulin levels. Such statements were con-
firmed in the study of SUGIYAMA et al. [46], where
the addition of grounded soybean into mixed meal
foods resulted in a significant (p < 0.001) decrease
of GI values.
In the present study, implementation of ama-
ranth flour into the control formulation led to the
reduction of GI by 12.6%, as opposed to findings
of CHATURVEDI et al. [47] who observed positive
dose-dependent relationship between the ama-
ranth flour added in the diet and GI values. Re-
sults were explained by physical properties of
amaranth starch (lower viscosity, high amylopectin
content, etc.). Taking into account that the strong
causal relationships were established between GI
values and macronutrient content in the examined
samples (Tab. 5), as well as lower in vitro starch
digestibility in biscuits enriched with amaranth, it
could be concluded that quoted macronutrients
and coarsely milled amaranth flour had a crucial
impact on the glucose response in vivo.
The buckwheat flour incorporation into the
biscuit formulation resulted in a slightly lower GI
value (by 2.3%), which was not statistically signifi-
cant. However, this effect suggests that the addi-
tion of buckwheat flour in larger quantities may
result in lower GI values of the final product. This
was previously indicated by ŠKRABANJA et al. [48],
who implemented 50% of buckwheat groats into
wheat-based bread and achieved a significant re-
duction in postprandial glucose and insulin levels,
compared with reference white wheat bread.
Inulin removal from the control biscuits result-
ed in an increase in GI (by 11.3%). The observed
effect was stronger in comparison to GI of sac-
charose-containing sample, where the presence of
saccharose instead of isomalt caused an increase
in GI by 9.5%. This observation indicates a strong
impact of inulin on the reduction of in vivo glu-
cose response. It can be explained by the fact that
inulin is highly hydrophilic and absorbs the water
present, thus inhibiting starch gelatinization and
digestion [49]. The obtained results are consistent
with those of BRENNAN et al. [50], who added up
to 10% of inulin in the wheat flour pasta recipe
and lowered starch digestibility in proportion to
the amount of the added inulin.
In the new millennium, the food industry is
faced with the challenge of formulating novel
products with optimal nutritional properties that
may have beneficial influence on human health.
The present study investigated the impact of
Tab. 5. Correlations between rapidly available glucose, different starch fractions
and macronutrient contents with glycemic index values.
r0.87 0.68 –0.78 –0.30 0.30 –0.70 –0.76 –0.73 –0.87 –0.95
p0.01* 0.09 ** 0.04 * 0.52 0.52 0.08 ** 0.05 * 0.07 ** 0.01 * 0.00 *
* – correlation significant at level p < 0.05, ** – correlation significant at level p < 0.1.
RAG – rapidly available glucose, RDS – rapidly digestible starch, SDS – slowly digestible starch, RS – resistant starch, TS – total
starch, SDF – soluble dietary fibre, IDF – insoluble dietary fibre, TDF – total dietary fibre.
RAG, starch fractions and macronutrient contents are expressed as grams per serving containing 50 g of available carbohydrates.
Vujić, L. et al. J. Food Nutr. Res., 53, 2014, pp. 152–161
an addition of selected raw materials on in vitro
starch digestibility as well as on in vivo glucose
response. Although in vitro methods cannot com-
pletely imitate conditions of digestion in the hu-
man body, a very good correlation between these
two approaches was observed. It suggested that
creation of biscuits with a low content of rapidly
available glucose and rapidly digestible starch, and
consequently with a high content of slowly digest-
ible starch, represents an effective way to lowering
the GI of this popular food. Therefore, in the era
of increasing demands for products with health-
enhancing effects, the obtained results could help
the confectionery industry to offer new products as
a part of a balanced diet, in particular for diabetics
and persons with impaired glucose tolerance.
1. Sudha, M. L. – Vetrimani, R. – Leelavathi, K.:
Influence of fibre from different cereals on the
rheological characteristics of wheat flour dough
and on biscuit quality. Food Chemistry, 100, 2007,
pp. 1365–1370.
2. Pareyt, B. – Talhaoui, F. – Kerckhofs, G. – Brijs, K. –
Goesaert, H. – Wevers, M. – Delcour, J. A.: The role
of sugar and fat in sugar-snap cookies: Structural and
textural properties. Journal of Food Engineering, 90,
2009, pp. 400–408.
3. Gambuś, H. – Gambuś, F. – Pastuszka, D. – Wro-
na, P. – Ziobro, R. – Sabat, R. – Mickowska, B. –
Nowotna, A. – Sikora, M.: Quality of gluten-free suple-
mented cakes and biscuits. International Journal of
Food Sciences and Nutrition, 60, 2009, pp. 31–50.
4. Zaker, A. – Genitha, T. R. – Hashimi, S. I.: Effects of
defatted soy flour incorporation on physical, senso-
rial and nutritional properties of biscuits. Journal of
Food Processing and Technology, 3, 2012, pp. 1–4.
5. Filipčev, B. – Šimurina, O. – Sakač, M. – Sedej, I. –
Jovanov, P – Pestorić, M. – Bodroža-Solarov, M.:
Feasibility of use of buckwheat flour as an ingredient
in ginger nut biscuit formulation. Food Chemistry,
125, 2011, pp. 164–170.
6. Hozová, B. – Buchtová, V. – Dodok, L. – Zemano-
vič, J.: Microbiological, nutritional and sensory
aspects of stored amaranth biscuits and amaranth
crackers. Nahrung, 41, 1997, pp. 155–158.
7. Takahama, U. – Hirota, S.: Fatty acids, epicate-
chin-dimethylgallate, and rutin interact with buck-
wheat starch inhibiting its digestion by amylase:
implications for the decrease in glycemic index by
buckwheat flour. Journal of Agricultural and Food
Chemistry, 58, 2010, pp. 12431–12439.
8. Capriles, V. D. – Coelho, K. D. – Guerra-Ma-
tias, A. C. – Arêas, J. A. G.: Effects of processing
methods on amaranth starch digestibility and pre-
dicted glycemic index. Journal of Food Science, 73,
2008, pp 160–164.
9. Kim, H. K. – Kim, M. J. – Cho, H. Y. – Kim, E.-K. –
Shin, D. H.: Antioxidative and anti-diabetic effects
of amaranth (Amaranthus esculantus) in strepto-
zocin-induced diabetic rats. Cell Biochemistry and
Function, 24, 2006, pp. 195–199.
10. Messina, M. J.: Legumes and soybeans: overview
of their nutritional profiles and health effects.
American Journal of Clinical Nutrition, 70, 1999,
pp. 439S–450S.
11. Avallone, R. – Plessi, M. – Baraldi, M. – Mon-
zani, A.: Determination of chemical composition of
carob (Ceratonia siliqua): protein, fat, carbohydrates,
and tannins. Journal of Food Composition and
Analysis, 10, 1997, pp. 166–172.
12. Marangoni, F. – Poli, A.: The glycemic index of
bread and biscuits is markedly reduced by the
addition of a proprietary fiber mixture to the ingre-
dients. Nutrition, Metabolism and Cardiovascular
Diseases., 18, 2008, pp. 602–605.
13. Jenkins, A. L. – Jenkins, D. J. A. – Wolever, T. M. S. –
Rogovik, A. L. – Jovanovski, E. – Božikov, V. – Rahe-
lić, D. – Vuksan, V.: Comparable postprandial glu-
cose reductions with viscous fiber blend enriched
biscuit in healthy subjects and patients with diabetes
mellitus: acute randomized controlled clinical trial.
Croatian Medical Journal, 49, 2008, pp. 772–782.
14. Englyst, H. N. – Kingman, S. M. – Cummings, J. H.:
Classification and measurement of nutri tionally
important starch fractions. European Journal of
Clinical Nutrition, 46, 1992, pp. S33–S50.
15. Jenkins, D. J. A. – Kendall, C. W. C. – Augus-
tin, L. S. A. – Franceschi, S. – Hamidi, M. –
Marchie, A. – Jenkins, A. L. – Axelsen, M.: Glycemic
index: overview of implications in health and disease.
American Journal of Clinical Nutrition, 76, 2002,
pp. 266S–273S.
16. Goni, I. – Garcia-Alonso, A. – Saura-Calixto, F.:
A starch hydrolysis procedure to estimate glycemic
index. Nutrition Research, 17, 1997, pp. 427–437.
17. Brouns, F. – Bjorck, I. – Frayn, K. N. – Gibbs, A. L. –
Lang, V. – Slama, G. – Wolever, T. M. S.: Glycaemic
index methodology. Nutrition Research Reviews, 18,
2005, pp. 145–171.
18. Approved methods of the AACC. 10th ed. St. Paul :
American Association of Cereal Chemists, 2000.
1200 pp. ISBN 1-891127-12-8.
19. Official methods of analysis. 17th ed. Washington :
Association of Official Analytical Chemists, 2000.
2200 pp. ISBN 0-935584-67-6.
20. Food energy – methods of analysis and conversion
factors. Food and Nutrition Paper 77. Rome : Food
and Agriculture Organization, 2003. 87 pp. ISBN
21. Langkilde, A. M. – Andersson, H. –
Schweizer, T. F. – Würsch, P.: Digestion and absorp-
tion of sorbitol, maltitol and isomalt from the small
bowel. A study in ileostomy subjects. European
Journal of Clinical Nutrition, 48, 1994, pp. 768–775.
22. Roberfroid, M. B.: Caloric value of inulin and
oligofructose. Journal of Nutrition, 129, 1999,
pp. 1436–1437.
23. Kumagai, T. – Kawamura, H. – Fuse, T. – Wata-
nabe, T. – Saito, Y. – Masumura, T. – Watanabe, R. –
Nutritional properties and glycemic index of whole grain wheat based biscuits
Kadowaki, M.: Production of rice protein by alka-
line extraction improves its digestibility. Journal
of Nutritional Science and Vitaminology, 52, 2006,
pp. 467–472.
24. Sacks, D. B.: Carbohydrates. In: Burtis, C. A. –
Ashwood, E. R. (Ed.): Tietz textbook of clinical
chemistry. 3rd Ed. Philadelphia : Saunders Company,
1999, p. 778. ISBN 0721-65610-2.
25. Carbohydrates in human nutrition. Food and
Nutrition Paper 66. Rome : Food and Agriculture
Organization, 1998. 140 pp. ISBN 92-5-104114-8.
26. Regulation (EC) No 1924/2006 of the European
Parliament and of the Council of 20 December 2006
on nutrition and health claims made on foods.
Official Journal of the European Union, L 404, 2006,
pp. 9–25.
27. Rayas-Duarte, P. – Mock, C. M. – Satterlee, D.:
Quality of spaghetti containing buckwheat, ama-
ranth, and lupin flours. Cereal Chemistry, 73, 1996,
pp. 381–387.
28. Rani, V. – Grewal, R. B. – Khetarpaul, N.: Sensory
and nutritional evaluation of soy supplemented
nutritious baked products. Journal of Dairying,
Foods and Home Sciences, 27, 2008, pp. 209–215.
29. Bilgiçli, N. – Ibanoğlu, Ş. – Herken, E. N.: Effect
of dietary fibre addition on the selected nutritional
properties of cookies. Journal of Food Engineering,
78, 2007, pp. 86–89.
30. Gilani, G. S. – Xiao, C. W. – Cockell, K. A.: Impact
of antinutritional factors in food proteins on the
digestibility of protein and the bioavailability of
amino acids and on protein quality. British Journal
of Nutrition, 108, 2012, pp. S315 – S332.
31. Ikeda, K. – Sakaguchi, T. – Kusano, T. – Yasu-
moto, K.: Endogenous factors affecting protein
digestibility in buckwheat. Cereal Chemistry, 68,
1991, pp. 424–427.
32. Singh, J. – Dartois, A. – Kaur, L.: Starch digestibility
in food matrix: a review. Trends in Food Science &
Technology, 21, 2010, pp. 168–180.
33. Oates, C. G.: Towards an understanding of starch
granule structure and hydrolysis. Trends in Food
Science & Technology, 8, 1997, pp. 375–382.
32. Ragaee, S. – Guzar, I. – Dhull, N. – Seethara man, K.:
Effects of fiber addition on antioxidant capacity
and nutritional quality of wheat bread. LWT–Food
Science and Technology, 44, 2011, pp. 2147–2153.
35. Bravo, L. – Englyst, H. E – Hudson, G. J.: Nutritional
evaluation of carbohydrates in the Spanish diet: Non-
starch polysaccharides and in vitro starch digestibil-
ity of breads and breakfast products. Food Research
International, 31, 1998, pp. 129–135.
36. Englyst, K. N. – Vinoy, S. – Englyst, H. N. – Lang, V.:
Glycaemic index of cereal products explained by
their content of rapidly and slowly available glucose.
British Journal of Nutrition, 89, 2003, pp. 329–339.
37. Lehmann, U. – Robin, F.: Slowly digestible starch –
its structure and health implications: a review.
Trends in Food Science and Technology, 18, 2007,
pp. 346–355.
38 Svihus, B. – Uhlen, A. K. – Harstad, O. M.: Effect
of starch granule structure, associated components
and processing on nutritive value of cereal starch:
a review. Animal Feed Science and Technology, 122,
2005, pp. 303–320.
39. Brand-Miller, J. – Foster-Powell, K.: Diets with a low
glycemic index: from theory to practice. Nutrition
Today, 34, 1999, pp. 64–72.
40. Garsetti, M. – Vinoy, S. – Lang, V. – Holt, S. –
Loyer, S. – Brand-Miller, J. C.: The glycemic and
insulinemic index of plain sweet biscuits: rela-
tionships to in vitro starch digestibility. Journal
of the American College of Nutrition, 24, 2005,
pp. 441–447.
41. Wolever, T. M. S.: Relationship between dietary
fiber content and composition in foods and glycemic
index. American Journal of Clinical Nutrition, 51,
1990, pp. 72–75.
42. Jenkins, D. J. A. – Thorne, M. J. – Wolever, T. M. S. –
Jenkins, A. L. – Venketschwer, R. – Thompson, L. U.:
The effect of starch-protein interaction in wheat on
the glycemic response and rate of in vitro digestion.
American Journal of Clinical Nutrition, 45, 1987,
pp. 496–451.
43. Berti, C. – Riso, P. – Monti, L. D. – Porrini, M.: In vitro
digestibility and in vivo glucose response of gluten-
free foods and their gluten counterparts. European
Journal of Nutrition, 43, 2004, pp. 198–204.
44. Packer, S. C. – Dornhorstt, A. – Frost, G. S.: The
glycaemic index of a range of gluten-free foods.
Diabetic Medicine, 17, 2000, pp. 657–660.
45. Blair, R. M. – Henley, E. C. – Tabor, A.: Soy
foods have low glycemic and insulin response indi-
ces in normal weight subjects. Nutrition Journal
[online]. Vol. 5, No. 35, 27 December 2006 [cit.
6 Juni 2013]. <
tent/5/1/35>. ISSN 1475–2891.
46. Sugiyama, M. – Tang, A. C. – Wakaki, Y. –
Koyama, W.: Glycemic index of single and mixed
meal foods among common Japanese foods with
white rice as a reference food. European Journal of
Clinical Nutrition, 57, 2003, pp. 743–752.
47. Chaturvedi, A. – Sarojini, G. – Nirmala, G. –
Nirmalamma, N. – Satyanarayana, D.: Glycemic
index of grain amaranth, wheat and rice in NIDDM
subjects. Plant Foods for Human Nutrition, 50, 1997,
pp. 171–178.
48. Škrabanja, V. – Liljeberg Elmståhl, H. G. M. –
Kreft, I. – Björck, I. M. E.: Nutritional properties of
starch in buckwheat products: studies in vitro and in
vivo. Journal of Agricultural and Food Chemistry,
49, 2001, pp. 490–496.
49. Tudorica, C. M. – Kuri, V. – Brennan, C. S.:
Nutritional and physicochemical characteristics of
dietary fiber enriched pasta. Journal of Agricultural
and Food Chemistry, 50, 2002, pp. 347–356.
50. Brennan, C. S. – Kuri, V. – Tudorica, C. M.: Inulin-
enriched pasta: effects on textural properties and
starch degradation. Food Chemistry, 86, 2004,
pp. 189–193.
Received 16 July 2013; 1st revised 23 September 2013;
accepted 30 October 2013; published online 5 May 2014.
... It is a rich source of proteins, dietary fibres, antioxidants, phenolic compounds, vitamins, essential minerals and resistant starch (RS). There are many studies showed that nutrients such as proteins, flavonoids, and thiamin-binding proteins of buckwheat had positive effects on controlling cholesterol, blood pressure, and serum glucose level (Bae et al. 2016;Vujic et al. 2014). ...
... Amaranth is an important protein source with its high content of essential amino acids such as lysine, methionine and cysteine which present limitedly in most cereal grains (Capriles et al. 2008;Caselato-Sousa and Amaya-Farfan 2012;Vujic et al. 2014). Furthermore, its high nutritional value and agronomic potential were demonstrated by the United States National Academy of Sciences (Caselato-Sousa and Amaya-Farfan 2012). ...
... Starch digestibility is affected by various factors such as nature and structure of starch source, protein and lipid interactions, the presence of antinutrients or enzyme inhibitors and process conditions. Therefore, a careful selection of grains is needed (Vujic et al. 2014). Since all grains are not equally nutritious, there is a requirement for comparing the health-related effects and processing performance of a variety of whole grains. ...
Chia, amaranth, quinoa and buckwheat grains have been widely used in food formulations because of their high and balanced nutritional properties. Since all grains are not equally nutritious, there is a requirement for comparing the health-related effects and processing performance of a variety of whole grains. The expected glycemic index (eGI) flours of chia was determined to be quite low, and flours except quinoa can be classified as low GI foods. The highest resistant starch (RS) content (4.76 g/ 100 g) was found in amaranth flour, and it was followed by buckwheat (1.27 g/100 g). The amaranth had the highest stimulation effect on the growth of probiotics and increased the count of L. acidophilus and B. bifidum as 4.57 and 2.26 log CFU/ml, respectively. Moreover, chia flour showed a positive effect on the growth of L. acidophilus whereas it negatively affected B. bifidum compared to the control. A significant correlation was detected between rapidly available glucose content and eGI. On the other hand, a significant relationship between RS and the growth rate of probiotics was reported.
... Obesity is a nutritional disorder caused by an imbalance between energy intake and expenditure (2). Over the last few decades, obesity, cardiovascular disease, and type 2 diabetes have been on the rise worldwide, in order to prevent those diseases, numerous studies have attempted to reduce starch digestion and glycemic index through human diets (3)(4)(5). Recent years have seen a growing interest in developing healthy food ingredients that may enhance their protein, fiber, and nutraceutical qualities (6). Therefore, macro-and micronutrients with high participation in the diet, such as starch and protein, need to be studied and in order to develop functional foods, nutritional value and technological function had to be balanced correctly (7)(8)(9). ...
Full-text available
The purpose of this experiment was to investigate the effects of different starch and protein levels on lipid metabolism and gut microbes in mice of different genders. A total of 160 male mice were randomly assigned to sixteen groups and fed a 4 × 4 Latin square design with dietary protein concentrations of 16, 18, 20, and 22%, and starch concentrations of 50, 52, 54, and 56%, respectively. The results of the study showed that different proportions of starch and protein had obvious effects on the liver index of mice, and there was a significant interaction between starch and protein on the liver index (p = 0.005). Compared with other protein ratio diets, 18% protein diet significantly increased the serum TBA concentration of mice (p < 0.001), and different starch ratio diets had no effect on serum TBA concentration (p = 0.442). It was proved from the results of ileal tissue HE staining that the low protein diet and the low starch diet were more favorable. There was a significant interaction between diets with different starch and protein levels on Bacteroidetes, Firmicutes and Proteobacteria abundance in feces of mice (p < 0.001). Compared with 16 and 18% protein ratio diets, both 20 and 22% protein diets significantly decreased the Parabacteroides and Alistipes abundance in feces of mice (p < 0.05), and 52% starch ratio diet significantly decreased the Parabacteroides and Alistipes abundance than 50% starch ratio diet of mice (p < 0.05). There was a significant interaction between diets with different starch and protein levels on Parabacteroides (p = 0.014) and Alistipes (p = 0.001) abundance in feces of mice. Taken together, our results suggest that a low protein and starch diet can alter lipid metabolism and gut microbes in mice.
... Increasing levels of carob flour in breads showed lower specific volume and higher crumb firmness and chewiness although protein content for G breads was higher than wheat bread. Several studies have also been performed for incorporating the carob flour into cakes (Rosa et al. 2015), and biscuits (Vujić et al. 2014). Carob flour usage is very promising approach for gluten free formulations since having caroubin which is a specific water-insoluble protein isolated from carob bean embryo. ...
Keçiboynuzu unu, çeşitli biyoaktif bileşikler, yüksek oranda lif, protein, vitamin ve mineral içerdiğinden fırıncılık ürünleri formülasyonlarında yaygın olarak kullanılmaktadır. Ekşi hamur fermantasyonu, fırıncılık ürünlerinin duyusal, tekstürel ve besinsel özelliklerini geliştirmede iyi bir araç olarak kabul edilmektedir. Bu çalışmanın amacı, keçiboynuzu unu ilave edilmiş Tip I ekşi hamurunun, ekmek yapımında kullanım potansiyelinin araştırılmasıdır. Keçiboynuzu unu ile karıştırılmış unlarda (%0, %2, %4, %6, %8 ve %12) ampirik reolojik ölçümler de yapılmıştır. Keçiboynuzu ununun artmasıyla su absorbsiyonu ve hamur gelişme süresi önemli ölçüde artmıştır (P ≤ 0.05). Numunelerin enerji ve uzayabilirlik değeri kontrol numunesine göre azalmıştır (P ≤ 0.05). Ekşi hamura keçiboynuzu unu ilavesinin artmasıyla ekşi hamurun maya sayısı azalmıştır (P ≤ 0.05). Keçiboynuzu unu ilavesi ile ekşi hamurda, kontrole (%0 keçiboynuzu) göre Laktik asit bakterilerinin gelişiminin teşvik edildiği belirlenmiştir (P ≤ 0.05). Fakat, artan keçiboynuzu ilavesi ile ekşi hamurlar arasında istatistiksel olarak bir fark gözlemlenmemiştir (P>0.05). Ekşi hamur fermentasyonu yolu ile keçiboynuzu unu kullanımı, aynı oranda keçiboynuzu unu içeren ticari mayalı ekmeğe göre ekmeğin kalite özelliklerini artırmıştır. Formülasyondaki en yüksek keçiboynuzu unu konsantrasyonu (%8 ve %12) sertliğin artmasına (P ≤ 0.05) neden olmuştur. Bu durum aynı zamanda ekmeğin spesifik hacmindeki azalma ile ilişkilendirilmiştir. Ticari mayalı ekmeğe, keçiboynuzu unu ilavesi, ekmeklerin parlaklık (L*) değerini azaltmıştır (P ≤ 0.05). Ekşi hamur fermantasyonu, keçiboynuzu unu katkılı ekmeklerin duyusal özelliklerini de geliştirmiştir. Ekşi hamur yapımında düşük seviyede keçiboynuzu unu kullanımı (%2-%6), bu çalışmadaki duyusal parametrelerin hiçbirini olumsuz yönde etkilememiştir.
... Thereby, the rapid digestible starch should be reduced or replaced as much as possible by slowly or non-digestible starch and high fiber sources. Possible alternatives with positive impact on the glycemic index of biscuits were defatted rice bran, apple pomace, pseudocereals (buckwheat or amaranth), legumes (soya and carob flour) or unripe banana flour (Agama-Acevedo et al., 2012;Alongi et al., 2019;Jia et al., 2020;Marangoni & Poli, 2008;Vujić et al., 2014). Furthermore, manipulating flour particle or using a flour with an increased particle size such as wholewheat flour is another interesting leverage to reduce the starch hydrolysis among bakery products (Lin et al., 2020). ...
In many parts of Europe, over 10% of children aged 5-19 are now obese, with overweight affecting up to a third of the children in some countries. Food reformulation is one lever to move toward a healthier food offer and to improve children’s’ diet. However, it faced with many challenges implying to consider food reformulation as a holistic approach including composition, sensory, physicochemical, liking or behavior dimensions. In this context, the aim of this PhD work was to propose a multicriteria approach to develop healthier products for children, while maintaining or optimizing sensory perception, liking and behavior. We chose to focus on chocolate-chip cookies as a case study.The first step of this work concerns the study of the recipe diversity of commercial cookies in France to select a representative subset of products. Nutrition, composition, economic, water content, and sensory information were thus analyzed on the cookies of the French market. Then, sensory, physicochemical analyses and liking evaluation with children (n=151, aged 7-12 years old) were conducted on a reduced subset of products to identify key opportunities for reformulation.In a second step, sensory-led formulation of cookies was proposed, based on a mixture design including four key ingredients (sugar, fat, chocolate-chips, oat bran), combined with one process factor (baking degree). Thirty reformulated cookies were thus developed and characterized on multiple criteria, including in vitro glycemic index or evolution during oral processing (time in mouth before swallowing). As main result, this approach led to propose possible reduction of the kcal (-5.9%), sugar (-15.9%), fat (-24.7%), and chocolate-chip (-20%) per cookie and increase in oat bran (+49.3%), with also improvement of the calculated glycemic index (-8.2%) and the Rayner score (-8.7%). This work led thus to sensory modeling and recipe optimization for healthier products.In addition, children’s perception, satiation and satiety and liking (n=80, aged 10-12 years) were evaluated for four of these reformulated cookies. Keeping a high level of liking by children was confirmed. In addition, we highlighted that cookies’ texture plays a key role in reformulation for children and oat bran might be an interesting lever to increase biscuits’ viscosity and therefore food oral processing.Thus, this multicriteria food reformulation approach might reinforce food reformulation as a promising tool to improve the food quality for children.
... In recent years, with the increasing epidemic of obesity, cardiovascular disease and type 2 diabetes worldwide, many researches have been carried out to attempt a reduction in digestion and glycemic index from starch in human diets to prevent those diseases (Dunn, Yang, Girard, Bean, & Awika, 2015;Giuberti, Gallo, Cerioli, Fortunati, & Masoero, 2015;Vujić et al., 2014). Some novel raw materials, such as soya, amaranth grain or buckwheat, with higher protein content than wheat have been applied to maintain and improve the nutritional quality and functional properties of the final product ( Filipčev et al., 2011). ...
... Furthermore, studies have shown that berry phenolic compounds inhibit digestive processes involved in starch breakdown and slow or modulate nutrient release from food at low level (Grussu et al., 2011;Boath et al., 2012). Since lower RAG and RDS content, and higher SDS content, are directly correlated with glycemic response (Vujić et al., 2014), addition of berry extracts seems to represent a convenient choice for lowering glycemic index of the final product. The antioxidant and radical scavenging properties of berry polyphenols have been studied extensively (Manganaris et al., 2014). ...
Full-text available
The aim of this research was to characterize the improvement in nutritional value, antioxidant activity as well as to evaluate textural and sensory properties of enriched biscuits. In this work black currant and jostaberry powder were used as ingredients for biscuits production since consumer demands for functional bakery products, like biscuits, are increasing. Obtained results showed that addition of berries to biscuits resulted in increase of total polyphenol and crude fibre content as well as antioxidant activity. Addition of berry powder resulted in decrease of rapidly available glucose and rapidly digestible starch. All examined antioxidant and sensory properties were improved when a chocolate coat was formed on the biscuits. Fracturabillity and hardness were affected by berry powder addition.
Germinated quinoa flour has been proven to be rich in a variety of nutrients, in order to improve the nutritional value and reduce the glycemic index of wheat noodle, 20% (w/w) of white quinoa (WQ), red quinoa (RQ), black quinoa (BQ) powder with different germination time were added to wheat noodle. The gemination rate, sprout length, digestion ratio and microstructure of WQ, RQ, and BQ were determined. Also, the characteristics of cooking, texture, digestion and blood glucose of noodles were studied. It was found that the addition of quinoa flour (WQ-0, WQ-1, RQ-0, RQ-1, BQ-0, BQ-3) maintained the cooking and texture characteristics of wheat noodle. Meanwhile, WQ-1, RQ-1, BQ-3 reduced the optimal cooking time and starch digestibility compared with wheat noodle. At the same time, it showed that the addition of WQ-1, BQ-3 significantly reduced the area under the blood glucose curve (AUC) to 132.17, 126.83 (mmol/L)·h, respectively. The correlation analysis verified that the digestion ratio was significantly positively correlated with AUC (p < 0.01). It will provide the theoretical basis for the development of new quinoa foods that lower blood sugar.
The aim of this study was to examine the effect of whey protein isolate (WPI) on the digestibility and physicochemical properties of potato starch (PS) after heat treatment. WPI reduced the digestibility of PS and increased the order and aggregation structure of gelatinized PS. Examination of the rheological properties of the PS-WPI mixed system before and after adding different chemicals (sodium chloride, urea, and sodium dodecyl sulfate) indicated an involvement of hydrogen bonds and hydrophobic interactions in the PS-WPI gelatinization system. The pasting properties, swelling power, and thermal properties indicated that WPI suppressed the swelling and gelatinization of PS. The addition of WPI reduced the amylose leaching rate from the starch granules, indicating that the presence of exogenous protein could prevent amylose diffusion from the starch granules. Native WPI and its hydrolysate also inhibited amyloglucosidase activity. These findings indicated that the mechanism by which WPI reduces PS digestion involves hydrophobic interactions and hydrogen bonding between WPI and PS, as well as enzyme activity inhibition.
Full-text available
Araştırmada bazı tahıl benzeri ürünlerin (çiya, amarant, kinoa ve karabuğday) glutensiz kek üretiminde kullanılabilirliğinin ve bu ürünlerin keklerin bazı özellikleri üzerine etkilerinin belirlenmesi amaçlanmıştır. Bu amaçla dört farklı kek unu karışımı; mısır (%45) ve pirinç (%45) nişastası ve tam tane olarak öğütülmüş tahıl benzeri ürünler (%10) kullanılarak hazırlanmıştır. Bu karışımlar ile üretilen kek örnekleri ve kontrol kek örneklerine; bazı fiziksel (renk, spesifik hacim ve tekstür), kimyasal (nem, su aktivitesi, dirençli nişasta, glisemik indeks ve antioksidan aktivite) ve duyusal analizler yapılmıştır. Kek örneklerinin sertlik ve çiğnenebilirlik değerlerinin 1234.21-1709.50g ve 668.09-996.27 aralıklarında değiştiği belirlenmiştir. Tahıl benzeri ürün ilavesiyle hazırlanan keklerin dirençli nişasta içeriklerinin %0.17-0.22 arasında olduğu ve tahmini glisemik indekslerinin ise 55 değerinden düşük olmaları sebebiyle düşük glisemik indeksli gıda sınıfı içerisinde yer alabileceği tespit edilmiştir. Yapılan değerlendirmeler neticesinde glutensiz keklerin çeşitlendirilmesinde tahıl benzeri ürünlerin kullanılabileceği ve bunların arasında ise çiyanın yumuşaklık, yüksek antioksidan aktivite ve duyusal özellikleri itibariyle öne çıktığı sonucuna ulaşılmıştır
For years and through two editions, Tietz's Fundamentals of Clinical Chemistry served as one of the major references in the field. In 1986, a closely related book, the first edition of Textbook of Clinical Chemistry, was published, followed by the third edition of Fundamentals of Clinical Chemistry in 1987. The major difference between these two versions—Textbook and Fundamentals—lies in the discussion of pathophysiology found in Textbook, while Fundamentals retained a more analytical laboratory- and methods-oriented approach. Eight years later and with the second edition of the Textbook, Dr Tietz has passed his editorship to two new and very capable successors. Although a good number of the chapter authors have changed, the book retains many of its important characteristics.
The anti-diabetic and antioxidative effect of amaranth grain (AG) and its oil fraction (AO) was studied in streptozotocin-induced diabetic rats. Male Sprague-Dawley rats were divided into four groups after induction of STZ-diabetes: normal control; diabetic control; diabetic-AG supplement (500 g kg(-1) diet); diabetic-AO supplement (100 g kg(-1) diet) and fed experimental diets for 3 weeks. Serum glucose, insulin, activities of serum marker enzymes of liver function and liver cytosolic antioxidant enzymes were measured. The AG and AO supplement significantly decreased the serum glucose and increased serum insulin level in diabetic rats. Serum concentration of liver function marker enzymes, GOT and GPT, were also normalized by AG and AO treatment in diabetic rats. Liver cytosolic SOD and GSH-reductase activities were significantly increased, and catalase, peroxidase and GSH-Px activities were decreased in diabetic rats. AG and AO supplement reverted the antioxidant enzyme activities to near normal values. Hepatic lipid peroxide product was significantly higher, and GSH content was decreased in diabetic rats. However, AG and AO supplement normalized these values. Our data suggest that AG and AO supplement, as an antioxidant therapy, may be beneficial for correcting hyperglycaemia and preventing diabetic complications. Copyright (c) 2005 John Wiley & Sons, Ltd.
The study was conducted to standardize the levels of defatted soy flour in composite flour for biscuit preparation. The defatted soy flour was incorporated in the traditional recipe to replace wheat flour at levels defatted soy flour by 0, 10, 20, and 30 percent in preparation of biscuits. Sugar was replaced by the Stevia and Date paste while traditional shortening was replaced by Olive oil. The prepared biscuits were evaluated for its physical, sensorial and nutritional properties. Result of sensory (appearance, color, flavor, texture, taste, and overall acceptability) evaluation of biscuits showed that 20% addition of defatted soy flour had higher overall acceptability, taste, texture and flavor. The nutritional value of the biscuit as determined through nutrient analysis-moisture (2.7), Protein (13.53), Fat (17.74), ash (1.75), and total energy (462.30) with 20 percent of defatted soy flour was comparable to control (wheat flour) biscuit.
Light and dark buckwheat, amaranth, and lupin flours were substituted for extra fancy and fancy durum wheat flours at 5, 15, 25, and 30% to produce multigrain pastas. The samples were analyzed for color, cooked weight, firmness, cooking loss (total solids) and total carbohydrate loss in the cooking water, in vitro protein digestibility, lysine content, and sensory attributes. Color scores of spaghetti containing light buckwheat and amaranth decreased as the substitution level increased. Color scores of dry spaghetti containing lupin remained constant at all substitution levels (10.3 average). The optimum cooking time of spaghetti was similar in all samples, about 11.3 min. The majority of the samples exhibited acceptable cooked weights of about three times the dry weight. The cooking loss ranged from 7,2 to 8.0%, significantly higher than that of the controls but still at acceptable levels. Samples containing dark buckwheat and amaranth showed significantly lower firmness values than the control durum-flour spaghettis. Total carbohydrate in the cooking water was independent of substitution level within a flour. Samples in which amaranth was substituted for durum showed the highest total carbohydrate in the water (2.7%), and those with lupin showed the lowest (1.2%). Lupin containing spaghetti showed higher in vitro protein digestibility content (86.4%) than did the controls and the other composite samples (averages 85.5 and 84.3%, respectively). The lysine content increased as the substitution level increased, and lupin-containing spaghetti showed the highest lysine values (average 3.2 g/100 g of protein). Sensory evaluation showed that changes in texture and flavor were detected at 30% light buckwheat, 15% dark buckwheat, 25% amaranth, and 15% lupin. The results showed that multigrain pasta can be produced with higher leveIs of lysine than commercial pasta made of 100% durum wheat flour and also with acceptable cooking quality and sensory attributes.
Non-starch polysaccharides (NSP) and the in vitro starch digestibility of breads and breakfast products typically consumed in Spain were studied. Total (TS), rapidly digestible (RDS), slowly digestible (SDS) and resistant (RS) starch fractions were determined, as well as starch digestion rate indexes (SDRI) and rapidly available glucose (RAG) values as indicatives of the amount of glucose likely to be liberated into the blood stream. Total NSP contents were relatively low, varying from 8.7% to 6.3% in some breakfast cereals and wholemeal breads, respectively, to only 0.5% in other breakfast products. Insoluble hemicelluloses were the main NSP. Starch was rapidly digestible, resulting in SDRI over 90% in most cases. In general, RAG values were high, mainly in some breakfast products due to the presence of high amounts of free glucose. Typical Spanish breakfast products and breads are thus characterised by their potentially high glycaemic and insulinemic responses.
Starch is organized in concentric alternating semi-crystalline and amorphous layers in granules of various sizes within the endosperm. The amount of amylose in starch normally varies between 200 and 300g/kg, but waxy cereals may contain negligible amounts and starch from high-amylose varieties may contain up to 700g amylose/kg. High amylose content is associated with reduced digestibility. Fat and protein are found on the surface of starch granules, and these components may act as physical barriers to digestion. Heat treatment with sufficient water present will cause gelatinisation that will increase susceptibility for starch degradation in the digestive tract, although a linear relationship between extent of gelatinisation due to processing and digestibility has not been found. The low water content during feed processing limits the extent of gelatinisation, but gelatinisation temperature and extent of gelatinisation will be affected by properties of the starch, which in turn may affect digestibility. The effect of starch properties and feed processing on digestion in non-ruminant animals and ruminants are discussed.
Dietary antinutritional factors have been reported to adversely affect the digestibility of protein, bioavailability of amino acids and protein quality of foods. Published data on these negative effects of major dietary antinutritional factors are summarized in this manuscript. Digestibility and the quality of mixed diets in developing countries are considerably lower than of those in developed regions. For example, the digestibility of protein in traditional diets from developing countries such as India, Guatemala and Brazil is considerably lower compared to that of protein in typical North American diets (54-78 versus 88-94 %). Poor digestibility of protein in the diets of developing countries, which are based on less refined cereals and grain legumes as major sources of protein, is due to the presence of less digestible protein fractions, high levels of insoluble fibre, and/or high concentrations of antinutritional factors present endogenously or formed during processing. Examples of naturally occurring antinutritional factors include glucosinolates in mustard and canola protein products, trypsin inhibitors and haemagglutinins in legumes, tannins in legumes and cereals, gossypol in cottonseed protein products, and uricogenic nucleobases in yeast protein products. Heat/alkaline treatments of protein products may yield Maillard reaction compounds, oxidized forms of sulphur amino acids, D-amino acids and lysinoalanine (LAL, an unnatural nephrotoxic amino acid derivative). Among common food and feed protein products, soyabeans are the most concentrated source of trypsin inhibitors. The presence of high levels of dietary trypsin inhibitors from soyabeans, kidney beans or other grain legumes have been reported to cause substantial reductions in protein and amino acid digestibility (up to 50 %) and protein quality (up to 100 %) in rats and/or pigs. Similarly, the presence of high levels of tannins in sorghum and other cereals, fababean and other grain legumes can cause significant reductions (up to 23 %) in protein and amino acid digestibility in rats, poultry, and pigs. Normally encountered levels of phytates in cereals and legumes can reduce protein and amino acid digestibility by up to 10 %. D-amino acids and LAL formed during alkaline/heat treatment of lactalbumin, casein, soya protein or wheat protein are poorly digestible (less than 40 %), and their presence can reduce protein digestibility by up to 28 % in rats and pigs, and can cause a drastic reduction (100 %) in protein quality, as measured by rat growth methods. The adverse effects of antinutritional factors on protein digestibility and protein quality have been reported to be more pronounced in elderly rats (20-months old) compared to young (5-weeks old) rats, suggesting the use of old rats as a model for assessing the protein digestibility of products intended for the elderly.