INTRODUCTIONCodonopsis javanica L., known in Vietnamese as“Dangsam”, is a member of the Campanulaceae family.It grows in the shade of trees and produces bell-shapedflowers [1–3]. C. javanica is a popular traditional herbalmedicine in China. In Vietnam, it can be found in 14mountainous Northern provinces, particularly in LangSon, Cao Bang, Ha Giang, Lao Cai, and Son La, at theheight of 500–1600 m above the sea level. It also growsin the highland areas of Southern provinces, includingQuang Nam, Lam Dong, and Kon Tum, at an altitudeof 1500 m [4, 5]. The habitats include pastureland,woodland edge in mountainous regions, hill slopes, andupland areas [6].C. javanica contains valuable bioactive compoundsand exhibits numerous pharmaceutical properties.Its root is known to contain glucose, essential oil,fatty substances, and alkaloids [7]. Past studiesthat employed nuclear magnetic resonance alsoregistered codotubulosins A and B, adenosine and5-(hydroxymethyl) furfural in quaternary ammoniumalkaloids in the C. javanica roots [8]. Codonopsis rootscontain such substances as polysaccharides, saponins,alkaloids, and phytosteroids, which significantlycontribute to the pharmacological efficacy of the plantmaterial [9, 10].Extracts of C. Javanica or other species ofcodonopsis were used to treat diabetes and otherillnesses [11–13]. They also possess strong antifatigue,antioxidant, antimicrobial, antitumor, and immuneboostingproperties [14–17]. In in vitro experiments,C. javanica extract showed mutagenic, antimutagenic,anticancer, and antitumor properties against varioushuman cell lines [18]. Polysaccharides from C. javanicawere demonstrated to protect mice with cerebralischemia-reperfusion injury [19]. Another experimentalso proved the antilarval properties of C. javanicaaqueous extract against Aedes albopictus pupae, a vectorof Dengue fever [20].In Vietnamese traditional medicine, C. javanica rootis used to treat a number of disorders related to digestiveand respiratory system [7]. Similar uses of C. javanicaroot were also reported in Chinese traditional medicine,the most popular preparation method being decoctionor tea brewing [21]. As a result of the recent interestin health beneficial natural ingredients, plant extractswith functional properties are often included in instanttea formulations [22]. Instant tea formulation has theadvantage of favorable aroma, stimulating effect, andconvenience. To avoid degradation, the final moisturecontent of instant tea powder samples is approximately3–5% [23].The research objective was to investigate theparameters of instant tea production from C. javanicaroot extracts by spray drying. The parameters underanalysis included moisture, drying yield, total saponincontent, and antioxidant activity.STUDY OBJECTS AND METHODSCondonopsis javanica L. roots were purchased fromthe local farmers in the province of Kon Tum, Vietnam.They were harvested during the winter season at theage of two years. Then the roots were cut into smallerpieces, and their moisture content was reduced from80.16% to 8.17% in a drying oven (Memmert UN110,Germany). The dried roots were mechanically powdered.Afterwards, 60% ethanol by volume was added to thepowder in the amount of 40 mL per 1 g. The suspensionwas then subjected to hydrodistillation for 4 h at 60°C.Water was removed with a rotary evaporator untilthe weight of the solid in the extract was 40.3%. Weobtained 65.75 g of dried extract from 100 g of input rootpowder. After multiple runs, the accumulated extractwas stored in a cooler for spray drying.To obtain instant tea, a drying additive(maltodextrin) was completely dissolved in 500 mL ofdistilled water and left at room temperature overnight.The solution was then mixed with the preparedC. javanica root extract at an appropriate ratio andthen with Tween 80. The amount of the added Tween80 equaled 5% of the weight of the prepared C. javanicaroot extract. After that, the mix was stirred at 6000 rpmfor 20 min in a rotor-stator blender to allow emulsionformation. About 800 mL of the mix was then put intoa lab-scale spray dryer (Pilotech YC-015 Mini SprayDryer). The first single-factor investigation involved theeffect of drying additive concentration on the propertiesof the product. The main spray drying parameterswere the following: drying temperature = 140°C, feedrate = 120 mL/h. The dry powder collected wasplaced in the airtight glass bottle at 25°C for furtherexamination.The moisture content of the product was determinedusing the AOAC International (AOAC, 2007) method.The sample was dried in an oven at 105°C till constantweight. The dried sample was then measured for weightloss (%) and the moisture content (%) [24].To determine drying yield, we used the followingformula [25]:where m1 is the weight of the feed solution (g), m2 isthe weight of the powder obtained by spray drying, x issolids, %, and y is the moisture content of the obtainedpowder product.ABTS scavenging activity was determined usingthe method previously described by Pham et al. andMradu et al. [26, 27]. To prepare the stock solution,10 mL of 7.4 mM ABTS solution was dropped to10 mL of 2.6 mM K2S2O8 and kept at room temperaturewithout exposure to light for 15 h for subsequent use.One milliliter of stock solution was diluted with 60 mLof methanol to get an absorbance value of 1.1 ± 0.02 at734 nm to produce the working solution. Then 0.5 mL ofthe extract was added to 1.5 mL of the working solutionand kept in darkness for 30 min at room temperature.A UV-VIS spectrophotometer recorded the absorbanceof the mix at 734 nm. Ascorbic acid was used as astandard, and the results were expressed as μg ascorbicacid equivalents per gram of dried sample (μgAA/g).To determine saponin content, 1 g of dried samplewas finely powdered and solubilized in 20 mL of20% isopropanol. The mixture was then heated ina microwave at 86°C for 20 min. The obtained mixwas then filtered using Whatman paper for furtherquantitative purpose.The saponin content was assessedspectrophotometrically as reported by Jennifer et al.,with minor modifications [28]. Briefly, 3.5 mL of theLiebermann ‒ Burchards (LB) reagent, consisting of a1:5 mix of acetic acid and sulfuric acid, was added to1 mL of sample solution. If saponins were present, thesample solution fluoresced with yellow. The saponin387Nhan N.P.T. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. Х–Хcontent in the solution was then quantified by measuringits absorbance at 580 nm. The following calibrationcurve describes the relationship between absorbance andsaponin concentration:Absorbance (mg/mL) = 4.5725 × Concentration ofsaponins (mg/mL) + 0.0164.Total saponins were calculated on the fresh weightbasis.The morphology of the spray-dried powderwas studied by a scanning electron microscope(JSM 6300 SEM). The samples were mounted directlyon aluminum SEM stubs in carbon conductive tape andcovered by gold sputtering with a thin layer of gold.Each measurement was carried out in triplicate.Statgraphic statistics software was used to evaluatethe 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 filmproperties with P = 0.05.RESULTS AND DISCUSSIONWe determined the moisture and texture of powderedtea from Condopopsis javanica L. root extract obtainedat various maltodextrin concentrations (Table 1). Highconcentrations seemed to result in the product withlower moisture and minor agglomerate formation.Fig. 1 shows the dependence of drying yield onmaltodextrin concentration. These impacts on dryingyield were statistically significant (P < 0.05), asdisplayed by the one-way ANOVA analysis. FurtherLSD multiple range tests for drying yield valuespointed out differences among the yields obtainedat five distinct concentrations (15, 20, 25, 30, 35%).The highest drying yield (75.68%) was attained atthe 30% concentration of maltodextrin. Generally,DY was directly proportional to the concentration thatrose from 15% to 30%. This can be explained by theeffect of exterior-active carbohydrates of maltodextrin,which attach with volatile compounds in theextracts [29]. As a result, higher concentrationsof drying additives could support the remainingvolatiles and simultaneously increase spray dryingyield. As noted by Nunes and Mercadante, the highconcentration of the drying additive (35% w/w) resultedin a caramelization reaction that produced furanones,furans, pyrones, and carbocyclic, thus reducing dryingyield [30]. Due to the economical characteristic ofmaltodextrin, we used 30% of maltodextrin in thesubsequent tests.Table 2 shows the texture and moisture of themicrocapsules obtained at different drying temperatures.Since an elevated temperature led to products withlower moisture content, we examined an effect ofdrying temperature on drying yield (Fig. 2). The resultswere statistically significant (P < 0.05), as displayed byTable 1 Moisture and texture of C. javanica instant teaat various maltodextrin concentrationsMaltodextrinconcentration, %Texture Moisture, %15 9.83 ± 0.08720 9.27 ± 0.07625 8.38 ± 0.06630 7.09 ± 0.0935 6.77 ± 0.05Figure 1 Drying yield of instant tea from C. javanica rootextract at different maltodextrin concentrations388Nhan N.P.T. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. Х–ХTable 2 Moisture and texture of instant tea from C. javanicaroot extract at different drying temperaturesDrying temperature, °C Texture Moisture, %140 6.77 ± 0.05160 6.6 ± 0.075180 6.01 ± 0.09200 5.013 ± 0.1Figure 2 Drying yield of instant tea from C. javanica rootextract at different drying temperaturesTable 3 Moisture and texture of instant tea from C. javanicaroot extract at different feed flow ratesFeed flow rate, mL/h Texture Moisture, %120 6.77 ± 0.05180 7.05 ± 0.076240 8.23 ± 0.112300 8.71 ± 0.13Figure 3. Drying yield of instant tea fromC. javanica root extract at different feed flow ratesthe one-way ANOVA analysis. Further LSD multiplerange tests for drying yield pointed out well-defineddifferences among the yields obtained at differenttemperatures (140, 160, 180, 200°C). The greatestdrying yield (75.68%) was achieved at 140°C. As thetemperature rose from 140 to 200°C, drying yielddecreased.As previously mentioned, high inlet/outlettemperature (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 drysubstance, leading to a rapid development of semipermeablemembrane on the droplet surface [31]. Theseresults are similar to the studies conducted by Fernandeset al. and Cortés-Camargo et al. [32, 33]. Consideringthe drying yield results, we decided to use the dryingtemperature of 140°C in out further experiments.389Nhan N.P.T. et al. Foods and Raw Materials, 2020, vol. 8, no. 2, pp. Х–ХTable 3 demonstrates the moisture and texture of theinstant tea at different feed flow rates. An increased feedflow rate improved the moisture in the obtained product.We then examined these differences of feed flow ratewith respect to drying yields, as shown in Fig. 3. Theseimpacts on drying yield were statistically significant(P < 0.05), as indicated by the one-way ANOVAanalysis. In addition, the yields obtained at differentparticular feed flow rates (120, 180, 240, 300 mL/h) werestatistically different. The largest drying yield (79.47%)was achieved at 300 mL/h. Generally, as the feed flowrate rose from 120 to 300 mL/h, drying yield increased.Jumah et al. showed that the feed flow rate was fasterat droplet atomization stage, which led to larger droplets.These droplets contained a high content of water and,subsequently, resulted in high moisture content in thepowdered product [33]. In addition, a higher feed flowrate increased drying yield. This could be explained bythe fact that a higher feed flow rate and higher dryingrates could reduce the dehydration time of the powder.On the other hand, a low moisture powder is usuallymixed with exhaust air, presenting difficulties forcyclonic separation [35]. These results are similar tothe studies conducted by Suzana F. Alves et al. andTomazelli Júnior et al. [36, 37]. Considering the dryingyield results, we chose the feed flow rate of 300 mL/h asoptimal for further experiments.Fig. 4 demonstrates the SEM photographs shrunkto microscopic scale of C. javanica instant tea obtainedwith 30% (w/w) concentration of maltodextrin at140°C. The particles had a comparatively regularshape and no visible breaks or ruptures were observed,proposing a satisfactory core retention and barrier of themicrocapsules. At low drying temperature, the shapeof the obtained particles was typically spherical witha shriveled and concave outer surface, indicating thatthe low drying temperature clearly provides a bettercore ingredient protection [38, 39]. Some particlesdemonstrated a smooth and rigid outer surface dueto quick evaporation. Therefore, the optimal dryingtemperature for instant tea production from C. Javanicaroot extracts using maltodextrin as a drying additivewas 140°C.We evaluated the saponin content and free radicalscavenging ability of the C. javanica extract and itspowder obtained by spray drying (Table 4). The resultsshowed that the saponin content in the extract washigher than that in the powdered tea by 0.29%. Theoriginal extract appeared to exert more scavengingactivity on ABTS free positive radicals with the totalantioxidant value at 168.88 μgAA/g. Meanwhile, afterspray drying, the total antioxidant value decreased, asexpressed by the reduced free radical capture activity.This implies that saponin in the C. Javanica extracthad the proton accept capacity and could serve asinhibitor of free radical and, probably, as a primaryantioxidant [1].CONCLUSIONIn the present study, we produced instant tea fromCondopopsis javanica L. root extract via spray drying.The maximum yield reached 78.35% at the concentrationof maltodextrin used as a drying additive of 30% (w/w),the drying temperature of 140°C, and the feed rate of300 mL/h. The resulting instant tea products had a hightotal saponin content (0.29%, w/w) and a good freeradical scavenging ability (59.48 μgAA/g). Therefore,the using of C. javanica root extract to produce instanttea is beneficial to commercialize the products forthe beverage market. Further studies are required toevaluate the sensory properties of the powdered productand examine the economic feasibility of the spray dryingprocess.CONTRIBUTIONNguyen Phu Thuong Nhan and Nguyen Duong Vuconceived and designed the analysis. Le Van Thanh,Nguyen Phu Thuong Nhan, and Than Thi Minh Phuongperformed the experiment and collected the data. LongGiang Bach and Tran Quoc Toan supervised the researchand wrote the paper.CONFLICTS OF INTERESTSThe authors declare that there is no conflictof interests regarding the publication of this article.