Developing mango powders by foam mat drying technology

Abstract Using mango purée from overripe mangoes to produce powders helped to solve agricultural product stagnation. The research investigates the effect of thickening additives, convection drying, and heat pump drying on bioactive compounds such as total phenolic content (TPC), total flavonoid content (TFC), color, and solubility of the final product. The obtained results showed that the mixture (gum arabic and maltodextrin in the ratio 50:50 w/w) at a concentration of 15% gave a good quality powder texture when dried by hot air convection at 55°C with TPC (21.24 ± 1.58 mg GAE/g dry weight [DW]) and TFC (0.34 ± 0.02 mg QE/g DW), respectively. In addition, the product has a high solubility of 64.35%, with the highest pass‐through point of 17.11.

methyl gallate, gallic acid, and astragalin that help prevent the formation of free radicals, help slow down the aging process, and prevent cancer. Mangoes contain high levels of vitamin C, pectin, and fiber, reduce serum cholesterol levels, help to improve blood lipid disorders, brighten eyes, strengthen the immune system, support the excretory system, and promote health (Huong et al., 2022;Maldonado-Celis et al., 2019).
Foam mat drying is an alternative to some technologies, such as spray drying and freezing drying. The liquid is whipped to form a stable foam and heat-dehydrated. The larger surface area of the foam accelerates the drying process to remove moisture quickly from highmoisture foods. Foam mat drying is converting a product from a liquid toastablefoamthatisthenair-dried.Stableair-liquidbubblesare the primary condition for successful foam mat drying. Proteins, gums, and various emulsifiers (e.g., glycerol monostearate, propylene glycerol monostearate, carboxymethyl cellulose, and trichlorophosphate) are used as foaming agents. Drying is carried out at relatively low temperatures to form a honeycomb-shaped sheet or sheet, which decays to produce a free-flowing powder. The larger surface area exposed to the drying air is the main cause of accelerated moisture loss (Quenzer&Burns,1977).However,capillarydiffusionisalsothemain cause of moisture migration inside the product during the drying processofthefoamsheet (Sankat&Castaigne,2004). The advantages of the foam mat drying process include suitability of all juices, quick drying at lower temperatures, preservation of nutritional qualities, ease of reconstitution, and efficiency for powder production fruit juiceeasytoreconstitute (Ratti&Kudra,2006). The foam carpet drying process is reported to be significantly cheaper than the vacuum, freeze,andspraydryingmethods (Kadametal.,2010).Severalrecent studies have shown interest in mango processing technology, such asthatofShendeandDatta(2020) that have optimized the refractive window drying process of mango cultivars of the Langra variety (Shende&Datta,2020).Kadametal.(2010) studied the process of foaming to create mango powder, by whipping the mango juice mixture with the addition of liquid milk (concentrations of 0%, 10%, 15%, 20%, and 25%), 8.5% of nonfat condensed milk (SNF), 4.5% of fat, 0.6%ofminerals,and3.3%ofprotein,withahandblenderfor3 min until a homogeneous foam is obtained. Then, the foam was poured into a steel tray, was spread, 3 mm thick, and dried at 65°C. After drying, it was scraped and ground into powder. The values of total sugar, ascorbic acid, total carotene content, and minerals retained high during processing and microbial content within the allowable thresholds(Kadametal.,2010). Dereje and Abera (2020) conducted a study on the effects of pretreatment and drying methods on the quality of dried mango slices. The survey results show that fluidized bed drying and freeze drying combined with pretreatment methods help retain the color and content of antioxidant compounds the best (Dereje&Abera,2020).
The Mekong Delta is the largest mango growing area in Vietnam, with 55% of the area spreading across provinces such as Dong Thap (about9600 ha,outputofmorethan90,000 tons/year),TienGiang,Can Tho,andBenTre,withmanyfamousmangovarieties:HoaLocmango, CatChumango,Tuongmango,Thommango,andTuQuymangowhich brings economic benefits to mango growers and Vietnam's agricultural economy (Phú & Khương, 2018). Among internationally traded tropical fruits, mangoes are second to bananas in quantity and fifth in total production among significant fruit trees worldwide. Mango production in the world is estimated at more than 26 million tons. India ranks first among the world's mango-producing countries, accounting for 54.2% of all mangoes produced worldwide and it is the most essential fruit tree in India, with over a thousand varieties known so far. Prominent mango exporting countries include China, Thailand, Indonesia, Philippines, Pakistan, and Mexico (Jahurul et al., 2015). The development of mango in both quantity and quality is significant for theagriculturaleconomyofVietnam.However,atpresent,themango growing provinces have not yet adequately assessed the value of mangoes. The complex problem of the country's agriculture is "good harvest, loss of value", reducing the income of mango growers. Tu Quy mango tree is considered one of the main crops of farmers in coastal communessuchasThanhPhong,ThanhHai,andGiaoThanh(Thanh Phu district) with more than 700 households participating in planting, with a total area of over 400 ha, the averageyield is 30-40 tons/ha, the average income is from 300 to 400 million/ha/year, and there is a tendency to increase the cultivated area. According to Agriculture Newspaper,TuQuymangoisalargefruit,withharvestedweightfrom 0.5to1 kg/fruit.Evergreenmango,whenripe,hasayellowish-green color, the fruit flesh also turns pale yellow (not as dark as sand mango) and it is one of the fruits with sudden respiratory properties.
From the above issues, to properly utilize and solve the problemofunsoldripemangoes,theresearchaimstouseTuQuymango purée to develop mango powder products applying foam mat drying technology to storage of compounds with antioxidant activity in mango.

| Preparation of material
Mango powders processing has been based on model of Kadam et al. (2010) and modified in Figure 1. Overripe mangoes are peeled and seeded, using the pulp to purée into purée. Then, the mango puréewaspretreatedat90°Cfor150 stoinactivatethebrowning enzyme. At the same time, 12% of egg white, 10% of milk, and 8.5% offatpowderwereaddedandwhippedwithawhiskfor3 min.Next, the whole mixture was mixed with the mango purée, the solution wasspreadonthedryingtraywithathicknessof2 mm,anddried at different temperature ranges according to arrangement until the moisture content reaches less than 3%. The mixture was ground finely, blended with thickener, and the product was packaged.

| Determination of total ascorbic acid
The ascorbic acid content was determined according to the method of AOAC 967.21, which was evaluated on cashews earlier by Dao et al. (2021).First,1 gofthesamplewasextractedthreetimesand thentitratedto100 mLwithdistilledwater.Next,10 mLofsample solutionaddedto1 mLof0.04%HClandtitratedwithDCPIP.The control sample was carried out in the same way as above, and the an-alyticalsamplewasdilutedwith0.1 gofascorbicacidupto100 mL.
Finally, both samples were repeated three times and titrated from colorlesssolutiontopalepinkwithin30 sandthevolumeofDCPIP solution was recorded.
Total ascorbic acid (TAA) content by dry weight (DW) is calculated as follows: where V 1 is the average DCPIP volume of the sample, mL; V 2 is the volume of the container of the extracted sample, mL; m 1 is the common standard mass of ascorbic acid, g; df is the sample dilution factor; V 3 is the DCPIP volume of ascorbic acid standard, mL; and m 3 is the sample mass according to the dry concentration, g.
The mixture was then incubated in the dark for 1 h before being measuredphotometricallyatanabsorptionwavelengthof765 nm.
Total polyphenol content (TPC) by DW is calculated as follows: where V 1 is the volume of the cuvet, mL; V 2 is the volume of the container of the extracted sample, mL; V 3 is the extract volume of fresh sample, mL; C 1 is the polyphenol concentration measured from Ultraviolet-Vis, μg/mL; and h is the moisture in the sample, %.

| Dissolution ability
The solubility was determined according to the method of Anderson (1982). Place 2.5 g powder and 30 mL distilled water in a 50 mL centrifuge tube. Shake the sample mixture vigorously for 1 min and incubate in a water bath at 37°C for 30 min, then centrifugeat2785 gfor20 min.Thesupernatantpowderwascollected, transferred to a petri dish, and dried at 105°C to constant (1) weight. The solubility (WAI) was calculated according to the following formula: where W s is the mass after drying and W i is the initial sample volume.

| Colorimetric method
The CIE Lab* color space is a reference color option based on three values L*, a*, and b* (Torres et al., 2011). Brightness was measured through a Chroma Scanner Colorimeter (model NR60CP). Results are displayed as numbers through L* (brightness ranges from 0 to 100), a* (green to red), and b* (blue to yellow) values.

| Sensory evaluation method
ImplementationmethodaccordingtoTCVN3215-79.Thisstandard specifies a method for checking the quality of food products by sensory scoring, applicable to check all the organoleptic criteria or each criterion (color, smell, taste, etc.) of each product and good. This method is based on assessing the sensation that appears according to its type and intensity.

| Statistical analysis
The experimental layout was triplicate and data were entered and processedbyExcelsoftware.TheprogramStatgraphicsCenturion XV.Iwasusedtoanalyzeone-factorANOVAatthesignificanceof the level of p < .05.

| Effect of mixing process on the quality of mango powder product
Color is an important quality indicator that affects consumer acceptance and the market potential of a product. The color parameters (L*, a*, b*, and ΔE*) and the surface change of mango pulp are presented in Table 1 and Figure 2, respectively. L* (darkness/brightness), a* (greenness/redness), and b* (blueness/yellowness) are used to calculate ΔE*. All color values of the carrier samples were increased compared with the mango purée sample. This was primarily due to the relatively high drying time and temperature leading to the color deterioration (Nhi et al., 2020;Zhao et al., 2015); however, the color is not too different from the mango purée.
The results in Table 1 and Figure 2 show that the color difference is significant when increasing the carrier concentration, as indicatedbythe∆E* value (the more significant the E* value, the greater the difference with the untreated sample.), and is partly due to the effects of drying temperature and the presence of carriers. However, they can act as a color fastness aid. In general, the color of the samples did not change too much. An increase in L* values indicates a decrease in the white color intensity due to yellow pigments (Manolopoulou & Varzakas, 2016). More prominently, the mixed gum arabic and maltodextrin sample showed that the solubility was 74.67%, and the color was moderate, not too much different from the pure mango powder sample. This may be because gum arabic has a higher viscosity and can form a more stable system than maltodextrin (Chen et al., 1998;. The mixture (gum arabic and maltodextrin in the ratio 50:50 w/w) was selected at a concentration of 15% for further experiments because of its good organoleptic qualities, no clumping, bright colors, aroma, and active activities; biology is less affected.

| Effect of foam mat drying on the quality of mango pulp
The solubility of mango powder given in Table 2 and colors in Figure 3 showed that with increasing convection drying tempera-  Ortiz et al., 2013).
Selecting convection drying technology at 55°C gave positive results in terms of color and high solubility, in addition to helping to preserve the highest biologically active ingredients.

| Effectofthickenerratioonthe product's taste
The results in Tables 3 and 4 showed that the solubility of mango purée samples in the presence of carriers (tapioca starch and cornstarch)washigherthanthatofsampleswithoutcarriers.However, the sample containing tapioca starch had better solubility than the sample containing cornstarch. The reason is that tapioca starch has betterwater-holdingcapacitythancornstarch (Hirai&Odani,1994).
The taste of the cornstarch sample was sourer than that of the tapioca sample (Ali et al., 2009). In addition, because the smell of cornstarch was partly related to the essential smell of mango powder, we have selected tapioca starch mixed with a concentration of 9% for good solubility and product appearance. likely that, because of the high total acid availability in the quartet mango purée, a low addition rate is more acceptable perceptually.

| Effectoftheproportionofflavoring
Therefore, the concentration of 0.005% citric acid was selected for TA B L E 2 Effectoffoammatdryingoncolordeviation,solubility,andbioactivecompounds. the acceptability of products to be circulated in the market.

| CON CLUS ION
In general, using auxiliaries in the drying process gave the product a high sensory score. From the obtained results, when using the convection drying method with foaming at 55°C, the drying time is shortened, with little effect on the color and the excellent appearance. In particular, the 15% arabic malto-gum mixture was selected for good organoleptic performance, the mango pulp was not clumped, the color was bright (with high similarity with the unprocessed purée sample), and the aroma of the fruit was preserved. The mango is naturally ripe and the sweetness is slightly sour. We successfully built a process to produce mango powder from sponge drying technology by convection drying with high sensory value and retaining biologically active compounds. From the data and color, it has been shown that the mixture containing gum arabic has better color retention, but the foam strength is not high. Therefore, a mixture containing a variety of gum and malto was selected for further studies so that the mango powder has the best organoleptic properties, foam stability, and solubility. The quality of mango powder products can be improved by adding functional compounds in upcoming studies.

ACK N OWLED G M ENTS
This work was supported by Ben Tre Department of Science and Technology, Ben Tre Province, Vietnam, and Nguyen Tat Thanh University, Ho Chi Minh City, Vietnam provides the facilities required to carry out this work.

FU N D I N G I N FO R M ATI O N
This research received no specific grant from any funding source.

CO N FLI C T O F I NTE R E S T S TATE M E NT
The authors declare that they have no conflict of interest. TA B L E 6 Effectsofflavoringadditives on the organoleptic taste of mango powder.

DATA AVA I L A B I L I T Y S TAT E M E N T
The data that support the findings of this study are available on request from the corresponding author.