INTRODUCTION
Codonopsis javanica L., known in Vietnamese as
“Dangsam”, is a member of the Campanulaceae family.
It grows in the shade of trees and produces bell-shaped
flowers [1–3]. C. javanica is a popular traditional herbal
medicine in China. In Vietnam, it can be found in 14
mountainous Northern provinces, particularly in Lang
Son, Cao Bang, Ha Giang, Lao Cai, and Son La, at the
height of 500–1600 m above the sea level. It also grows
in the highland areas of Southern provinces, including
Quang Nam, Lam Dong, and Kon Tum, at an altitude
of 1500 m [4, 5]. The habitats include pastureland,
woodland edge in mountainous regions, hill slopes, and
upland areas [6].
C. javanica contains valuable bioactive compounds
and exhibits numerous pharmaceutical properties.
Its root is known to contain glucose, essential oil,
fatty substances, and alkaloids [7]. Past studies
that employed nuclear magnetic resonance also
registered codotubulosins A and B, adenosine and
5-(hydroxymethyl) furfural in quaternary ammonium
alkaloids in the C. javanica roots [8]. Codonopsis roots
contain such substances as polysaccharides, saponins,
alkaloids, and phytosteroids, which significantly
contribute to the pharmacological efficacy of the plant
material [9, 10].
Extracts of C. Javanica or other species of
codonopsis were used to treat diabetes and other
illnesses [11–13]. They also possess strong antifatigue,
antioxidant, antimicrobial, antitumor, and immuneboosting
properties [14–17]. In in vitro experiments,
C. javanica extract showed mutagenic, antimutagenic,
anticancer, and antitumor properties against various
human cell lines [18]. Polysaccharides from C. javanica
were demonstrated to protect mice with cerebral
ischemia-reperfusion injury [19]. Another experiment
also proved the antilarval properties of C. javanica
aqueous extract against Aedes albopictus pupae, a vector
of Dengue fever [20].
In Vietnamese traditional medicine, C. javanica root
is used to treat a number of disorders related to digestive
and respiratory system [7]. Similar uses of C. javanica
root were also reported in Chinese traditional medicine,
the most popular preparation method being decoction
or tea brewing [21]. As a result of the recent interest
in health beneficial natural ingredients, plant extracts
with functional properties are often included in instant
tea formulations [22]. Instant tea formulation has the
advantage of favorable aroma, stimulating effect, and
convenience. To avoid degradation, the final moisture
content of instant tea powder samples is approximately
3–5% [23].
The research objective was to investigate the
parameters of instant tea production from C. javanica
root extracts by spray drying. The parameters under
analysis included moisture, drying yield, total saponin
content, and antioxidant activity.
STUDY OBJECTS AND METHODS
Condonopsis javanica L. roots were purchased from
the local farmers in the province of Kon Tum, Vietnam.
They were harvested during the winter season at the
age of two years. Then the roots were cut into smaller
pieces, and their moisture content was reduced from
80.16% to 8.17% in a drying oven (Memmert UN110,
Germany). The dried roots were mechanically powdered.
Afterwards, 60% ethanol by volume was added to the
powder in the amount of 40 mL per 1 g. The suspension
was then subjected to hydrodistillation for 4 h at 60°C.
Water was removed with a rotary evaporator until
the weight of the solid in the extract was 40.3%. We
obtained 65.75 g of dried extract from 100 g of input root
powder. After multiple runs, the accumulated extract
was stored in a cooler for spray drying.
To obtain instant tea, a drying additive
(maltodextrin) was completely dissolved in 500 mL of
distilled water and left at room temperature overnight.
The solution was then mixed with the prepared
C. javanica root extract at an appropriate ratio and
then with Tween 80. The amount of the added Tween
80 equaled 5% of the weight of the prepared C. javanica
root extract. After that, the mix was stirred at 6000 rpm
for 20 min in a rotor-stator blender to allow emulsion
formation. About 800 mL of the mix was then put into
a lab-scale spray dryer (Pilotech YC-015 Mini Spray
Dryer). The first single-factor investigation involved the
effect of drying additive concentration on the properties
of the product. The main spray drying parameters
were the following: drying temperature = 140°C, feed
rate = 120 mL/h. The dry powder collected was
placed in the airtight glass bottle at 25°C for further
examination.
The moisture content of the product was determined
using the AOAC International (AOAC, 2007) method.
The sample was dried in an oven at 105°C till constant
weight. The dried sample was then measured for weight
loss (%) and the moisture content (%) [24].
To determine drying yield, we used the following
formula [25]:
where m1 is the weight of the feed solution (g), m2 is
the weight of the powder obtained by spray drying, x is
solids, %, and y is the moisture content of the obtained
powder product.
ABTS scavenging activity was determined using
the method previously described by Pham et al. and
Mradu et al. [26, 27]. To prepare the stock solution,
10 mL of 7.4 mM ABTS solution was dropped to
10 mL of 2.6 mM K2S2O8 and kept at room temperature
without exposure to light for 15 h for subsequent use.
One milliliter of stock solution was diluted with 60 mL
of methanol to get an absorbance value of 1.1 ± 0.02 at
734 nm to produce the working solution. Then 0.5 mL of
the extract was added to 1.5 mL of the working solution
and kept in darkness for 30 min at room temperature.
A UV-VIS spectrophotometer recorded the absorbance
of the mix at 734 nm. Ascorbic acid was used as a
standard, and the results were expressed as μg ascorbic
acid equivalents per gram of dried sample (μgAA/g).
To determine saponin content, 1 g of dried sample
was finely powdered and solubilized in 20 mL of
20% isopropanol. The mixture was then heated in
a microwave at 86°C for 20 min. The obtained mix
was then filtered using Whatman paper for further
quantitative purpose.
The saponin content was assessed
spectrophotometrically as reported by Jennifer et al.,
with minor modifications [28]. Briefly, 3.5 mL of the
Liebermann ‒ Burchards (LB) reagent, consisting of a
1:5 mix of acetic acid and sulfuric acid, was added to
1 mL of sample solution. If saponins were present, the
sample solution fluoresced with yellow. The saponin
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content in the solution was then quantified by measuring
its absorbance at 580 nm. The following calibration
curve describes the relationship between absorbance and
saponin concentration:
Absorbance (mg/mL) = 4.5725 × Concentration of
saponins (mg/mL) + 0.0164.
Total saponins were calculated on the fresh weight
basis.
The morphology of the spray-dried powder
was studied by a scanning electron microscope
(JSM 6300 SEM). The samples were mounted directly
on aluminum SEM stubs in carbon conductive tape and
covered by gold sputtering with a thin layer of gold.
Each measurement was carried out in triplicate.
Statgraphic statistics software was used to evaluate
the statistical data (Statpoint Technologies, version 20,
Inc., Warrenton, VA, USA). The variance analysis
(ANOVA) and the least significant difference (LSD)
were calculated to compare the mean value of the film
properties with P = 0.05.
RESULTS AND DISCUSSION
We determined the moisture and texture of powdered
tea from Condopopsis javanica L. root extract obtained
at various maltodextrin concentrations (Table 1). High
concentrations seemed to result in the product with
lower moisture and minor agglomerate formation.
Fig. 1 shows the dependence of drying yield on
maltodextrin concentration. These impacts on drying
yield were statistically significant (P < 0.05), as
displayed by the one-way ANOVA analysis. Further
LSD multiple range tests for drying yield values
pointed out differences among the yields obtained
at five distinct concentrations (15, 20, 25, 30, 35%).
The highest drying yield (75.68%) was attained at
the 30% concentration of maltodextrin. Generally,
DY was directly proportional to the concentration that
rose from 15% to 30%. This can be explained by the
effect of exterior-active carbohydrates of maltodextrin,
which attach with volatile compounds in the
extracts [29]. As a result, higher concentrations
of drying additives could support the remaining
volatiles and simultaneously increase spray drying
yield. As noted by Nunes and Mercadante, the high
concentration of the drying additive (35% w/w) resulted
in a caramelization reaction that produced furanones,
furans, pyrones, and carbocyclic, thus reducing drying
yield [30]. Due to the economical characteristic of
maltodextrin, we used 30% of maltodextrin in the
subsequent tests.
Table 2 shows the texture and moisture of the
microcapsules obtained at different drying temperatures.
Since an elevated temperature led to products with
lower moisture content, we examined an effect of
drying temperature on drying yield (Fig. 2). The results
were statistically significant (P < 0.05), as displayed by
Table 1 Moisture and texture of C. javanica instant tea
at various maltodextrin concentrations
Maltodextrin
concentration, %
Texture Moisture, %
15 9.83 ± 0.087
20 9.27 ± 0.076
25 8.38 ± 0.066
30 7.09 ± 0.09
35 6.77 ± 0.05
Figure 1 Drying yield of instant tea from C. javanica root
extract at different maltodextrin concentrations
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Table 2 Moisture and texture of instant tea from C. javanica
root extract at different drying temperatures
Drying temperature, °C Texture Moisture, %
140 6.77 ± 0.05
160 6.6 ± 0.075
180 6.01 ± 0.09
200 5.013 ± 0.1
Figure 2 Drying yield of instant tea from C. javanica root
extract at different drying temperatures
Table 3 Moisture and texture of instant tea from C. javanica
root extract at different feed flow rates
Feed flow rate, mL/h Texture Moisture, %
120 6.77 ± 0.05
180 7.05 ± 0.076
240 8.23 ± 0.112
300 8.71 ± 0.13
Figure 3. Drying yield of instant tea from
C. javanica root extract at different feed flow rates
the one-way ANOVA analysis. Further LSD multiple
range tests for drying yield pointed out well-defined
differences among the yields obtained at different
temperatures (140, 160, 180, 200°C). The greatest
drying yield (75.68%) was achieved at 140°C. As the
temperature rose from 140 to 200°C, drying yield
decreased.
As previously mentioned, high inlet/outlet
temperature (140°C) led to a caramelization reaction,
thus decreasing drying yield [29]. Jafari et al.
demonstrated that a relatively high inlet air temperature
(160–220°C) may cause thermal damage to a dry
substance, leading to a rapid development of semipermeable
membrane on the droplet surface [31]. These
results are similar to the studies conducted by Fernandes
et al. and Cortés-Camargo et al. [32, 33]. Considering
the drying yield results, we decided to use the drying
temperature of 140°C in out further experiments.
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Table 3 demonstrates the moisture and texture of the
instant tea at different feed flow rates. An increased feed
flow rate improved the moisture in the obtained product.
We then examined these differences of feed flow rate
with respect to drying yields, as shown in Fig. 3. These
impacts on drying yield were statistically significant
(P < 0.05), as indicated by the one-way ANOVA
analysis. In addition, the yields obtained at different
particular feed flow rates (120, 180, 240, 300 mL/h) were
statistically different. The largest drying yield (79.47%)
was achieved at 300 mL/h. Generally, as the feed flow
rate rose from 120 to 300 mL/h, drying yield increased.
Jumah et al. showed that the feed flow rate was faster
at droplet atomization stage, which led to larger droplets.
These droplets contained a high content of water and,
subsequently, resulted in high moisture content in the
powdered product [33]. In addition, a higher feed flow
rate increased drying yield. This could be explained by
the fact that a higher feed flow rate and higher drying
rates could reduce the dehydration time of the powder.
On the other hand, a low moisture powder is usually
mixed with exhaust air, presenting difficulties for
cyclonic separation [35]. These results are similar to
the studies conducted by Suzana F. Alves et al. and
Tomazelli Júnior et al. [36, 37]. Considering the drying
yield results, we chose the feed flow rate of 300 mL/h as
optimal for further experiments.
Fig. 4 demonstrates the SEM photographs shrunk
to microscopic scale of C. javanica instant tea obtained
with 30% (w/w) concentration of maltodextrin at
140°C. The particles had a comparatively regular
shape and no visible breaks or ruptures were observed,
proposing a satisfactory core retention and barrier of the
microcapsules. At low drying temperature, the shape
of the obtained particles was typically spherical with
a shriveled and concave outer surface, indicating that
the low drying temperature clearly provides a better
core ingredient protection [38, 39]. Some particles
demonstrated a smooth and rigid outer surface due
to quick evaporation. Therefore, the optimal drying
temperature for instant tea production from C. Javanica
root extracts using maltodextrin as a drying additive
was 140°C.
We evaluated the saponin content and free radical
scavenging ability of the C. javanica extract and its
powder obtained by spray drying (Table 4). The results
showed that the saponin content in the extract was
higher than that in the powdered tea by 0.29%. The
original extract appeared to exert more scavenging
activity on ABTS free positive radicals with the total
antioxidant value at 168.88 μgAA/g. Meanwhile, after
spray drying, the total antioxidant value decreased, as
expressed by the reduced free radical capture activity.
This implies that saponin in the C. Javanica extract
had the proton accept capacity and could serve as
inhibitor of free radical and, probably, as a primary
antioxidant [1].
CONCLUSION
In the present study, we produced instant tea from
Condopopsis javanica L. root extract via spray drying.
The maximum yield reached 78.35% at the concentration
of maltodextrin used as a drying additive of 30% (w/w),
the drying temperature of 140°C, and the feed rate of
300 mL/h. The resulting instant tea products had a high
total saponin content (0.29%, w/w) and a good free
radical scavenging ability (59.48 μgAA/g). Therefore,
the using of C. javanica root extract to produce instant
tea is beneficial to commercialize the products for
the beverage market. Further studies are required to
evaluate the sensory properties of the powdered product
and examine the economic feasibility of the spray drying
process.
CONTRIBUTION
Nguyen Phu Thuong Nhan and Nguyen Duong Vu
conceived and designed the analysis. Le Van Thanh,
Nguyen Phu Thuong Nhan, and Than Thi Minh Phuong
performed the experiment and collected the data. Long
Giang Bach and Tran Quoc Toan supervised the research
and wrote the paper.
CONFLICTS OF INTERESTS
The authors declare that there is no conflict
of interests regarding the publication of this article.
