Introduction

Although pumpkins (Cucurbita spp.) are widely grown as vegetable crops worldwide, there is a notable disparity between the amount produced and the amount consumed because they are not widely used as a food source. Numerous studies have documented the potential significance of pumpkin fruits, seeds, pulp and flowers for their nutritional value, medicinal properties, and pharmacological aspects. This is because pumpkins are high in protein, carbohydrates and vitamins, particularly antioxidants and phytochemicals.¹

The Apiaceae family includes many flowering plants, notably including carrots (Daucus carota L.), among other root vegetables and herbs. Carrots are heavily consumed worldwide, and can be eaten raw, cooked, in pulp, powder or juice. The carrot is adored for its rich nutrients, superior flavor and revitalizing mouthfeel. It is added to a variety of other foods because it contains a high concentration of carotenoids, fibers, vitamins, antioxidants and other minerals. Carrots are recommended for uterine pain and are beneficial in addressing kidney illnesses and dropsy, while also acting as nervine tonics and aphrodisiacs.²

Thailand has traditionally utilized lemongrass (Cymbopogon citratus), a member of the Poaceae family, for culinary and medicinal purposes. Beneficial characteristics of this plant include anti-inflammatory, antifungal, antinociceptive and antioxidant actions. Lemongrass essential oil has been shown in animal experiments to have sedative, anticonvulsive and anti-anxiety properties. A recent human study showed that when male volunteers are exposed to an artificial anxiogenic scenario, inhaling lemongrass essential oil has anxiolytic benefits and lowers subjective stress.³

One useful naturally occurring sweetener which can be beneficial to health through its various properties, including anti-inflammatory effects, is stevia syrup (Stevia rebaudiana), which contains valuable steviol glycosides.⁴ Stevia is an alternative sweetener which is low in calories and often finds a role as a dessert ingredient. For example, it is sometimes used in jam without sugar.⁴

There are many different health drinks on the market at present and they are becoming more and more popular since they taste good are reasonably priced and are conveniently packaged. Since the products are usually in powdered or ready-to-drink form, they can be kept in storage for an extended period of time. For these powdered drinks, there are various drying techniques available, such as hot air oven, spray drying, drum drying and foam mat drying.⁵

Food products are frequently preserved using foam mat drying, which offers advantages such as shortening the drying time with hot air and better preservation of the dried food quality.⁶

In the foam mat drying process, a stable foam is produced from the original food in liquid (or semi-liquid) form, which is then hot air dried resulting in a dried powder.⁷ The benefits of employing such a drying method are that the drying procedure takes place more quickly and at cooler temperatures because the porosity of the foam ensures that the surface area which is open to the air is much larger, thus allowing an increase rate of drying. The approach is also appropriate when used with foods which might be highly viscous, high in sugar, or simply sensitive to heat, for which alternative drying approaches are not suitable.⁸ The foam characteristics can be described in terms of stability and expansion, which is the ability to form the foam.⁹ There are several factors affecting foam characteristics such as whipping time and whipping temperature and the type including the amount of foaming and foam stabilizing agent employed. When foaming agents are added along with stabilizing agents, this provides foam stability by reducing the surface tension and causing foaming of the liquid and semi-liquid.¹⁰ Common foaming agents include egg albumen and CMC. At the surface, foaming ability can be enhanced by egg white, which contains globulin, which is a very effective protein in this foaming context.¹¹ CMC is a hydrocolloid gum used as a foam stabilizing agent. It was possible to enhance the foam stability through an increase in the interfacial viscoelasticity of the foam lamellae.¹² Related products were the subject of four related research studies. Firstly, it was necessary to determine the method of making drinking powder items by employing foam mat drying to generate powdered carrot, orange, and lemon. The ideal proportions of orange, lemon and carrot to create a powder quickly through foam mat drying must also be considered. Six treatments were performed whereby each used a different ratio for the components of orange to lemon to carrot: (1) 100:0:0 (control); (2), 75:20:5; (3) 70:20:10; (4) 50:40:10; (5) 50:45:5, and (6) 62:31:7. For each of the tested samples for the various treatment protocols, there were no substantial changes in brightness, color, or solubility (p>0.05), according to the data. Investigations were conducted on the chemical properties, such as total soluble solid, moisture, β-carotene, antioxidant activity, ascorbic acid and pH values. The treatment for which the carrot: orange: lemon ratio was 50: 40: 10 was shown to have the highest amounts of β-carotene at 3.68 mg Trolox eq/g, and antioxidants at 0.14 μg/100 g FW. Using a 9-point hedonic scale for sensory evaluation of taste and overall acceptability, the expert panel members expressed a preference for Treatment 4, awarding scores of 5.70 for taste and 6.33 for acceptability.⁶ Next, the impacts of the foaming agents were evaluated for the agent comprising 15% egg albumen and the agent comprising 15% egg albumen plus 10% whey protein isolate. Thin-layer foaming models were assessed at different thicknesses to test the carrot juice drying behavior when foam mat drying was conducted at temperatures of 50, 60 and 70°C. The carrot juice foam drying times were shown to be dependent upon temperature and foam thickness; in this case the drying time was reduced by 25-60% in comparison to the control, which comprised solely carrot juice.¹³ Next, the papaya pulp was whipped for 5, 10 and 15 minutes at varying glycerol monostearate concentrations (1%, 2%, 3% and 4% w/w). The pulp concentration including the foaming agent at the 1% level had a substantial impact on the foam expansion. With a 9°Brix pulp content, 3% glycerol monostearate and a 10-minute whipping duration, the highest stable foam formation was 90%. The resultant foams were air-dried inside a batch-type cabinet drier at 2.25 m³/min air flow at various temperatures (60, 65 and 70°C) along with foam thicknesses (2, 4, 6 and 8 mm). Longer drying times were the result of ticker foams and cooler temperatures for the frying process.¹⁴ One very recent study compared the characteristics of mango powder obtained via the process of foam mat drying with that produced through the utilization of various foaming agents. Fresh Mahajanaka mango puree (Mangifera indica L.) from northern Thailand is combined with sugar, GMS and SBI in varying proportions to create foam. The mixture is then dried for five hours at 70°C in a tray drier. There is no correlation between the moisture content, solubility and hygroscopicity values of sugar and GMS at different ratios. The optimal powder quality is achieved by adding 1% GMS and 5% sugar while storing at 90% relative humidity and 38 ± 2°C.¹⁵

A brief review of the literature as described confirms that while previous studies have examined the drying process in the context of certain fruits and vegetables, no work exists on the subject of mixtures of pumpkin, carrot and lemongrass by foam mat drying.

Considering the advantages of the three types of ingredients, it can be seen that they are inexpensive, simple to find all year round and contain active ingredients that are beneficial to the body. However, the existing studies do underline the importance of foam mat drying, which is relatively quick and allows the powder to retain its nutritional qualities. In addition, there are further advantages associated with the ingredients of pumpkin, carrot and lemongrass which arise due to their antioxidant properties and the various bioactive compounds they contain. One crucial aspect of the drying process is that drying can have adverse consequences for the chemical and physical properties of powdered foods. A quicker process can help to limit the extent of this decline.¹⁶ This study also places emphasis upon the effects on the physicochemical and microbiological qualities of the resulting food product due to varying the quantities of stevia syrup. The influence of the syrup upon the sensory assessment is also an important factor for consideration. It is also advantageous that all of the fruit and vegetable ingredients in addition to the stevia syrup are readily available at reasonable cost, in addition to offering various health benefits for the human body due to their bioactive ingredients. For example, stevia can help in controlling weight and blood sugar levels. Once these ingredients have been turned into liquid foam, they can then be dried via the foam mat process to create a healthy powdered food product. For this product to be at its most effective, it is necessary to optimize the conditions under which the drying process takes place, so these conditions must be determined. Furthermore, the use of combinations of local ingredients found in Thailand can support small and medium-sized businesses in the country, offering opportunities for both farmers and entrepreneurs to profit.^10,11

This current study therefore sought to establish the nature of the optimal drying parameters along with the most suitable stevia syrup ratio. Two different foaming agents were tested and the researchers examined the outcomes in terms of physicochemical and microbiological qualities along with measures of the color, odor, water solubility, brightness, foam density, foam stability, overrun, yield, water activity, moisture, protein, fat, ash, antioxidant activity, β-carotene, total plate count outcome and sensory assessment.

Materials and Methods

Raw materials were studied in this research, namely the pumpkins, carrots and lemongrass, which were bought from Talad Nud Khlong 6 in Pathum Thani Province, Thailand and transferred to the laboratory for this research. The study made use of analytical grade chemicals obtained from Sigma with a purity of 99.8% and suitable for use in food products.

Raw material preparation

A neutral detergent (H₂O) was used to wash the pumpkins and eliminate dirt from the surface. The pumpkins were then sliced and the 3 cm slices were cooked in boiling water for 1 minute. After cooling, the slices were peeled including an any remaining seeds were removed. A fork was then used to mash the slices to create a puree, which was filtered using cheesecloth and then packaged in pouches of 300 g to 50 mL of water.¹⁶

Regular tap water was used to wash the fresh carrots and the excess water was then removed. The carrots were then chopped into pieces of size 4 cm, which were peeled. These pieces were introduced to a juice extractor to produce carrot juice containing carrot pulp. The pulp was taken out and the juice was poured into glass bottles which were heated to 95°C in a water bath for 5 minutes. After being allowed to cool to 4°C, the juice was then filtered using cheesecloth.¹³

Regular tap water was used to wash the fresh lemongrass and the excess water was then removed. The lemongrass was then chopped into pieces of size 5 cm and blanched at 80°C for 1 minute before filtering through cheesecloth.¹⁷

The prepared pumpkin, carrot, and lemongrass along with additional ingredients as shown in Table 1^13,16,17 were mixed together until homogeneous using an electric blender for 5 minutes. After that, they were placed upon an aluminum tray and spread out to dry under hot air in an oven for 6-7 hours (or until completely dry) at a temperature of 70°C.^13,16,17

Table 1: Composition of each ingredient for mixed pumpkin, carrot and lemongrass production

N.B. Treatment 1 is control 

Foam mat drying of mixed pumpkin, carrot and lemongrass powder

The foam of the mixed pumpkin, carrot and lemongrass was prepared from raw materials by mixing fresh egg albumen (12 g) and CMC (6 g) using a food mixer (KitchenAid Model K-5, USA) with a wire whisk at 1,000 rpm (speed setting 10) for 5 minutes. The 2 mm thick foam was spread on a flat aluminum tray (25 cm × 25 cm) and hot air dried following the conditions obtained from the preliminary study at 70°C for 90 minutes. The dried product was scratched, ground using a laboratory blender (Waring blender 7011HS, USA) at 14,000 rpm (speed setting 1) for 15 seconds and vacuum packed in an aluminum foil bag. The foam of the mixed pumpkin, carrot and lemongrass was reconstituted in warm water (60°C) in the ratio of 1:1 (w/v) prior to the determination of the physicochemical, microbiological and sensory attributes.¹⁸ 

Physicochemical and microbiological quality of mixed pumpkin, carrot and lemongrass powder

The characteristics of the dried foam were analyzed using a Mini Scan XE in order to measure the color and brightness of the samples in terms of (L)*, (+a*) and (+b*).¹⁹ In addition, water solubility,¹⁹ moisture content,¹⁹ water activity,¹⁹ protein,¹⁹ fat,¹⁹ ash,¹⁹ antioxidant activity (DPPH assay),²⁰ β-carotene,²¹ foam density,²² foam stability,²³ overrun (%),²³ yield (%)²³ and total plate count¹⁹ were assessed and assigned a value.

Sensory evaluation

In order to measure the sensory qualities of the samples, a 9-point hedonic scale was utilized. A panel comprising 30 participants who had received no training in sample evaluation were asked to give their ratings for each of the sample powders, which had undergone reconstitution at a 1:1 ratio using drinking water.²⁴ 

Data analysis

The study employed a CRD (for physicochemical analysis) instead of a RCBD (for sensory evaluation) which might be used in experimental cases. The differences observed between treatments were evaluated via both ANOVA and DMRT (p < 0.05). Data were presented as the actual values measured as mean+ standard deviation, with each of the treatment investigated in triplicate. The data were computed using PASW Statistics version 18.²⁴ 

Results 

Tables 2-8 present the outcomes for each of the various properties of the different powders of mixed pumpkin, carrot and lemongrass.

Table 2: Foam density foam expansion percentage, overrun percentage and yield percentage of mixed pumpkin, carrot and lemongrass powder

N.B: *Items in the same column indicated by letters in superscript (a-d) identify significant differences (p<0.05).

Treatment 1 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 0 (control)

Treatment 2 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 50

Treatment 3 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 30

Treatment 4 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 20

Table 3: Water activity and moisture of mixed pumpkin, carrot and lemongrass powder

N.B: *Items in the same column indicated by letters in superscript (a-d) identify significant differences (p<0.05).

Treatment 1 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 0 (control)

Treatment 2 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 50

Treatment 3 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 30

Treatment 4 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 20

Table 4: Protein, fat  and ash of mixed pumpkin, carrot and lemongrass powder

N.B: *Items in the same column indicated by letters in superscript (a-d) identify significant differentces (p<0.05).

Treatment 1 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 0 (control)

Treatment 2 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 50

Treatment 3 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 30

Treatment 4 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 20

Table 5: β-carotene and DPPH of mixed pumpkin, carrot and lemongrass powder

N.B: ns indicates non-significance (p>0.05).

Treatment 1 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 0 (control)

Treatment 2 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 50

Treatment 3 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 30

Treatment 4 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 20

Table 6: Brightness, redness, yellowness and water solubility of mixed pumpkin, carrot and lemongrass powder

N.B: *Items in the same column indicated by letters in superscript (a-c) identify significant differences (p<0.05).

Treatment 1 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 0 (control)

Treatment 2 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 50

Treatment 3 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 30

Treatment 4 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 20

Table 7: Microbiological properties of mixed pumpkin, carrot and lemongrass powder

N.B: Treatment 1 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 0 (control)

Treatment 2 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 50

Treatment 3 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 30

Treatment 4 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 20

Table 8: Sensory scores of mixed pumpkin, carrot and lemongrass powder

N.B: *Items in the same column indicated by letters in superscript (a-b) denote significant differences (p<0.05). ns means non-significant (p>0.05).

Treatment 1 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 0 (control)

Treatment 2 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 50

Treatment 3 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 30

Treatment 4 pumpkin: carrot: lemongrass: stevia 55: 140: 55: 20

Discussion

All values were significantly different (p<0.05). Treatment 1 achieved the highest foam density (Table 2). The probable reason was that no stevia syrup was added, so there was no barrier to dissolution, resulting in the highest density. Reducing the amount of stevia syrup results in a higher foam density, leading to a less stable foam. Higher foam density resulted in a prolonged drying time and lower volume expansion, in turn reducing the quality of the product as a consequence of thermal degradation.^25-29

The process of foam mat drying depends heavily upon the foam stability because the foam must remain mechanically and thermally stable throughout the whole procedure.³² In this study, Treatment 2 saw the foam stability decrease significantly (65.11 ± 0.14), possibly as a consequence of the high quantities of thin film bubble which were produced during the whipping, whereupon groups of cells are able to coalesce to form a single large cell at a later time. Adding more stevia syrup had less effect on foam dispersion, resulting in a reduced foam stability percentage. The liquid flows between the dispersed cells’ bubbles could force them closer together leading to a loss of stability.^25-29

In considering the foam characteristics, the overrun percentages for mixed pumpkin, carrot and lemongrass powder can be seen in Table 2, where the findings revealed that Treatment 1 exhibited the highest foam overrun percentage (88.25 ± 0.52), followed by Treatments 2, 3 and 4, respectively. The highest foam overrun in Treatment 4 indicated that a large amount of air was entrapped in the bubbles of the foam structure, developing a noticeable foam expansion and considerably decreasing the foam density (0.72 ± 0.28 g/mL). The reduction of density is attributed to the rapid moisture dislocation throughout the drying operation as it provided a great surface area for the drying air.^26-29

Treatment 1 achieved the highest yield percentage (15.29 ± 0.11). The decreasing stevia syrup will expand the surface area and give a porous structure due to the high amount of air trapped, so that water can evaporate easily and increase the drying rate. The reason was similar to that given for the overrun percentage value. The reduction of stevia syrup resulted in a reduction in total soluble solids, which results in a decrease in solids content, resulting in an increase in the overrun percentage and yield percentage.^26-27

From Table 3, examination of the chemical properties found that all parameters were significantly different (p<0.05).  In the context of powders produced via foam mat drying, the water activity is a critical parameter. Water activity is not the same as moisture, but instead acts as a measure of the amount of free water that a food system contains. The water is a critical component permitting various biological activities.^5,6 Values for water activity in the powder ranged from 0.33 to 0.54 as shown in Table 3 and account for the proportion of water within the composition of the food as a whole.^5,6 If the moisture content of a food powder does not exceed 10%, the product can be considered safe in microbiological terms.^5,6 In this case, the trends in the measured values for the water activity and moisture both decreased with decreases in amounts of stevia syrup. The highest value of water activity and moisture were observed in Treatment 1 at 0.54 and 7.57%, respectively. Furthermore, there is a reduction is solid content since this will bind to the water, leading to a reduction in both moisture and water activity.^5,6 If the water activity value does not exceed 0.60, it can be considered that the food is microbiologically stable, from which it can be inferred that if the food spoils, it is not the result of microbiological process but can instead be attributed to chemical changes.³⁰

From Table 4, the reduction in the amount of stevia syrup resulted in an increase in the protein, fat and ash values (p<0.05). This may be due to the increase in protein values, partly from the addition of egg whites that make the egg white rise, which has protein as the main component. Another part is that the reduction in the amount of stevia causes the solubility to decrease, resulting in an increase in the protein values. The fat values ​​tend to decrease in the same way as the protein values, probably due to the reduction in the amount of stevia syrup causing the fat values ​​to increase. The ash values ​​tend to be the same as the protein and fat values.³¹

Analyses of the DPPH assay and β-carotene were performed and these data are shown in Table 5. Data analysis of both β-carotene and antioxidants showed no statistical differences (p>0.05). The results of β-carotene analysis in all treatments were closed and had no statistical differences (p>0.05). One possible reason is that the starting materials were in the same proportion, resulting in no differences in the measured values from the reduction of stevia syrup. The analyzed values for each treatment were very low, in addition to the same amount of starting raw materials in all treatments. Part of the loss of β-carotene came from the raw material preparation process and the drying process through heating by oxidation or exposure to very high heat, air and sunlight. Therefore, such processing causes losses.^5,6,32 The antioxidant values ​​by DPPH method for each treatment were very similar, for the same reasons as the β-carotene values. Reducing the amount of stevia syrup did not affect the antioxidant values. The samples were shown to have similar links between the antioxidant and β-carotene qualities and while there were no differences in the antioxidant properties, it can be explained that antioxidant capabilities are determined by the concentration and the chemical structure, since these qualities govern the subsequent interactions.^5,6 Moreover, it is also possible to improve the antioxidant activity by adjusting the temperature used for the drying process. Among the reactions of interest, the Maillard reaction can lead to products which exhibit very strong antioxidant qualities.^5,6 Higher drying temperatures increase the likelihood of Maillard reactions, and in turn the likelihood of Maillard products being created, with increased antioxidant potential.²⁵ In addition, the drying process can also sometimes induce oxidation, which results in increased antioxidant activity from the resulting oxidized polyphenols when compared to the activity of non-oxidized polyphenols.²⁵

The reduction of stevia syrup in mixed pumpkin, carrot and lemongrass powder resulted in a tendency to reduce the values associated with redness, yellowness and overall brightness when ​​compared to the control (p<0.05). Treatment 1 showed the highest brightness, redness and yellowness values ​​because stevia is a pure stevioside crystal particle (white powder). When in liquid form, the product becomes more turbid, which may be due to partial sedimentation of suspended particles in pumpkin, carrot and lemongrass that are not dissolved in the fruit juice. In addition, it is also due to the joint factors of tissue structure and components in the fruit, including pectin compounds that are extracted and suspended in the fruit juice, causing turbidity in the juice, which affects the measurement of the brightness and color values,³⁴ in concurrence with Carbonell-Capella³⁵; Nimitkeatkai and Potaros.³⁰ Lower intensity for brightness, redness and yellowness can be attributed to decreased amounts of the stevia syrup. The temperature affects the start of the browning reaction in egg white powder.²⁸ High temperatures may also cause damage to the pigments found within the mixed pumpkin, carrot and lemongrass. It may therefore be the case that the browning reaction can take place during the foam mat drying process and this can in turn accelerate the observed decreases in brightness, redness and yellowness as the stevia syrup content was reduced. Other reactions, including the caramelization and Maillard reactions can occur during drying and inside the final product because the mixed pumpkin, carrot and lemongrass contains sugars and amino acids. The temperatures reached during drying are maintained inside the drying tray and can thus promote these reactions. The mixed pumpkin, carrot and lemongrass powder is a brown orange color.^27,32

The water solubility was shown in Table 6. The mixed pumpkin, carrot and lemongrass soluble powder in Treatment 2 gave the lowest value for water solubility, while Treatment 1 had the highest water solubility. When the products were blended, dried and sifted into powder, it was found that the powder was crumbly and stuck to the hands. The water solubility was not good. This was because the amount of stevia syrup added affected the drying process. Adding a large amount of stevia syrup reduces the water solubility of the product, causing it to become more turbid.¹⁸

The findings presented in Table 7 reveal bacteria values not exceeding 1 × 10⁴ for any of the treatments. Meanwhile, no treatment had water activity greater than 0.60, from which it can be inferred that the products were both stable and safe in the context of microorganism growth inhibition.^5,6 It appears that bacterial growth in the mixed juice product is restricted, which may be due to the heat processing in the steps of the raw material preparation and foam mat drying process under good hygienic conditions with GMP.^5,6 This study was in concurrence with Hirunyophat³¹ who reported that in pasteurized Chock–Anan raw mango juice, the total plate count showed at <1 CFU/mL.

The outcomes from the sensory assessment using the 9-point hedonic scale can be observed in Table 8. The scores from this scale allow the general level of acceptability of the product to be determined in line with the specified criteria.³¹ Data analysis confirmed that no significant differences (p>0.05) could be observed for any of the values with the exception of taste, which was statistically different (p<0.05). From the results of the study, it was found that reducing the amount of stevia syrup resulted in a higher acceptance scores from the expert panel members, who could clearly distinguish the taste differences. This is because when stevia syrup is added to the product, it causes an astringent and bitter aftertaste. In addition, the results of the study were consistent with Hirunyophat³¹ who found that when increasing the amount of stevia syrup in pasteurized Chokanan mango juice products, the overall sensory scores tend to decrease. Onsamlee³⁶ found that increasing the concentration of stevia extract in young coconut fresh milk pudding products tends to decrease the overall liking score when compared to the control sample. In addition, Yildiz and Karhan³⁷ reported that the use of stevia extract in beverage products may cause an astringent and bitter aftertaste in the throat, which may affect sensory acceptance. Krasaekoopt and Bhatia²⁹ reported that the preference scores of flavor, texture and general acceptability in the yogurt powder production using foam mat drying were not significant (p>0.05).

Conclusion 

It has been determined that the foam-mat drying process shortens the drying time of mixed pumpkin, carrot and lemongrass by 90 minutes at the same drying temperature. The best conditions for producing mixed pumpkin, carrot and lemongrass powder by using foam mat drying were provided by Treatment 4 as a low calorie sweetener with the mixing time of 5 minutes and drying temperature of 70°C for 90 minutes. The mixed pumpkin, carrot and lemongrass foam had very high foam stability, low foam density, a high overrun percentage and a high yield percentage. Microbiological analysis revealed that quality of the mixed pumpkin, carrot and lemongrass powder met the required safety standards. The sensory score of mixed pumpkin, carrot and lemongrass powder (Treatment 4) was 6.30 for taste. Future studies may focus on the shelf life of the products including other fruits and vegetables, other foaming agents and more suitable packaging for the extension of shelf life.

Acknowledgment

The author would like to acknowledge the 4^th grade students (30 persons for sensory evaluation) and supporting staff (Miss.Kanittha Sookkerd) of the Department of Agro Industrial Technology, the Faculty of Agricultural Technology Rajamangala University of Technology Thanyaburi (RMUTT), Pathum Thani Thailand that carried out this research. 

Funding Sources

The author received financial support from Faculty of Agricultural Technology Rajamangala University of Technology Thanyaburi Pathum Thani Thailand for the research, authorship, and publication of this article. The research work was funded by Grant’s name (Grant No.) 2023/003 dated 10-03-2023.

Conflict of Interest

The author does not have any conflict of interest.

Author Contributions

The sole author was responsible for the conceptualization, methodology, data collection, analysis, writing and final approval of the manuscript.

Data Availability

This manuscript incorporates all datasets examined throughout this research study. 

Ethics Statement

This research did not involve human participants, animal subjects, or any material that requires ethical approval.

Informed Consent Statement

This study did not involve human participants, and therefore, informed consent was not required.

Permission to Reproduce Material from other Sources

Not applicable.

Clinical Trial Registration

This research does not involve any clinical trials.

References

1. Himani Ruwanthika K. O. G., Mayuri S. Munasinghe M. L. A., Upul J. Marapana R. A. Overview of Cucurbita spp. (Pumpkin) and Development of Value-Added Products Emphasizing Its Nutritional and Chemical Composition. World Adv Res Rev Jour. 2023;18(2):1215–1226. https://doi.org/10.30574/wjarr.2023.18.2.0938
   CrossRef
2. Noella J., Umuhoza K., Sylvestre H., Philippe S. Nutritional Quality of Carrot (Daucus carota L.) as Influenced by Farm Yard Manure. World Agri Sci Jour. 2014;2(5):102–107.
3. Sriraksa N., Kaewwongse M., Phachonpai W., Hawiset T. Effects of Lemongrass (Cymbopogon citratus) Essential Oil Inhalation on Cognitive Performance and Mood in Healthy Women. Thai Pharm Health Sci Jour. 2018;13(2):80-88.
4. Samakradhamrongthai R. S., Nortuy N., Sangsee O., Srichan P., Sangpimpa W., Jannu T., Supawan T., Chanakun P., Yimkaew Y., Renaldi G. Effect of Stevia Syrup, Okra Fruit Powder and Thai White Chili on Physicochemical Properties and Sensory Qualities of Confectionery Jam. LWT- Food Sci Tech Jour. 2024;194:1-11. https://doi.org/10.1016/j.lwt.2024.115797
   CrossRef
5. Wirivutthikorn W. Development of Spray Drying of Powdered Oolong Tea Incorporated with Chinese Jujube Beverage. Curr Res Nutr Food Sci Jour. 2024;12(2):805-816. https://dx.doi.org/10.12944/CRNFSJ.12.2.25
   CrossRef
6. Wirivutthikorn W. Processing Development of Instant Juice Powder Product from Carrot Orange and Lemon by Using Foam Mat Drying. Burapa Sci Jour. 2022;27(1):48-65.
7. Lobo F. A. T. F., Domingues J., Falcão D., Stinco C., Rodríguezpulido F., Faria C. E., Heredia F., Gomes de Lima Araujo K., Vila D. Foam Mat Drying of Tommy Atkins Mango: Effects of Air Temperature and Concentrations of Soy Lecithin and Carboxymethyl Cellulose on Carotenoid Compounds and Colourimetric Parameters. Food Chem Nanotech Jour. 2020;6(1):1-8. https://doi.org/10.17756/jfcn.2020-077
   CrossRef
8. Noordia A., Mustar Y. S., Kusnanik N. W. Foam Mat Drying of Banana Juice: Varieties of Ripe Banana Analysis and Egg Albumen Foam. Food Sci Tech (Brazil)  Jour. 2020;40(2):465-468. https://doi.org/10.1590/fst.24918
   CrossRef
9. Azizpour M., Mohebbi M., Yolmeh M., Abbasi E., Sangatash M. M. Effects of Different Hydrocolloids on Foaming Properties of Shrimp Puree: A Cluster Analysis. Food Meas Charact Jour. 2017;11(4):1892-1898. https://doi.org/10.1007/s11694-017-9571-9
   CrossRef
10. Qadri O. S., Srivastava A. K., Yousuf B. Trends in Foam Mat Drying of Foods: Special Emphasis on Hybrid Foam Mat Drying Technology. Crit Rev Food Sci Nutr Jour. 2020;60(10):1667-1676. https://doi.org/10.1080/10408398.2019.1588221
    CrossRef
11. Lau K., Dickinson E. Structural and Rheological Properties of Aerated High Sugar Systems Containing Egg Albumen. Food Sci Jour. 2004;69(5):E232-E239. https://doi.org/10.1111/ j.1365-2621.2004.tb10714.x
    CrossRef
12. Dickinson E. Structuring of Colloidal Particles at Interfaces and the Relationship to Food Emulsion and Foam Stability. Colloid Interf Sci Jour. 2015;449:38-45. https://doi.org/10.1016/j.jcis.2014.09.080
    CrossRef
13. Cakmak H., Ozyurt V. H. Foam-Mat Drying of Carrot Juice and Thin Layer Modeling of Drying. Hittite Sci Eng Jour. 2021;8(4):347–354.   https://doi:10.17350/HJSE19030000248
    CrossRef
14. Kandasamy P., Varadharaju N., Kalemullah S. Foam-Mat Drying of Papaya (Carica papaya L.) Using Glycerol monostearate as Foaming Agent. Food Sci Qual Manag Jour. 2012;9(1):17-27.
15. Sansomchai P., Sroynak R., Tikapunya T. Powder Qualities of Foam-Mat Dried Mango. Trends in Sci Jour. 2023;20(5):1-7. https://doi.org/10.48048/tis.2023.5308
    CrossRef
16. Santos L. C. O., Simão V., Opuski de Almeida J. D. S., Moura de Sena Aquino, A. C., Carasek E., Amante E. R. Study of Heat Treatment in Processing of Pumpkin Puree (Cucurbita moschata). Agri Sci Jour. 2017;9(10):234-243. https://doi:10.5539/jas.v9n10p234
    CrossRef
17. Lonkar P. B., Chavan U. D., Pawar V. D., Bansode V. V., Amarowicz R. Studies on Preparation and Preservation of Lemongrass (Cymbopogon flexuosus (Steud)  Wats) Powder for Tea. Emirates Food Agri Jour. 2013;25(8):585-592.   https://doi:10.9755/ejfa. v25i8.15218
    CrossRef
18. Eadmusik S., Yangyuen V. Jitpen K., Juthapong K. Production of Foam-Mat Dried Chili Shrimp Paste and Its Properties.  Food Res Jour. 2024;8(3):163-171. https://doi.org/10.26656/fr.2017.8(3).249
    CrossRef
19. AOAC. Official Methods of Analysis. 17^th ed. The Association of Official Analytical Chemists (AOAC), Washington, D.C.; 2000.
20. Burguieres E., McCue P., Kwon Y. I., Shetty K. Effect of Vitamin C and Folic Acid on Seed Vigour Response and Phenolic-Linked Antioxidant Activity. Biore Tech Jour. 2007;98(7):1393-1404. https://doi.org/10.1016/j.biortech.2006.05.046
    CrossRef
21. Maoka T. Carotenoids as Natural Functional Pigments. Nat Med Jour. 2019;74(5):1- https://doi.10.1007/s11418-019-01364-x
    CrossRef
22. Ng M. L., Sulaiman R. Development of Beetroot (Beta vulgaris) Powder Using Foam Mat Drying. LWT-Food Sci Tech Jour. 2018;88:80-86. https://doi.org/10.1016/j.lwt.2017.08.032
    CrossRef
23. Kanha N., Regenstein J. M., Laokuldilok T. Optimization of Process Parameters for Foam Mat Drying of Black Rice Bran Anthocyanin and Comparison with Spray and Freeze-Dried Powders. Drying Tech Jour. 2020;40(3):581-594.    https://doi.org/10.1080/07373937. 2020.1819824
    CrossRef
24. Wiriyajari P. Sensory Evaluation. Department of Product Development Technology, Faculty of Agro-Industry, Chiang Mai University. Chiang Mai; 2018. Cakmak H., Ozyurt V. H. Foam Stability of Cloudy Carrot Juice: Effects of Protein Sources and Foaming Conditions. The Annals of the University of Dunarea de Jos of Galati. Fascicle VI– Food Tech Jour. 2021;45(1):38-51. https://doi.org/10.35219/ foodtechnology.2021.1.03
    CrossRef
25. Sangamithra A. S., Venkatachalam S., John S. G., Kuppuswamy K. Foam Mat Drying of Food Materials: A Review. Food Proc Pres Jour. 2014;39(6):3165-3174. https://doi. org/10.1111/jfpp.12421
    CrossRef
26. Chumlert K., Daengsakon N., Rassmeedara P., Phanumong P. Production of Instant Mixed-Vegetables Soup Using Foam Mat Drying: Impact of Various
27. Additives on Foam Properties and Physicochemical Aspects. Food Agri Sci Tech  Jour. 2024;10(1):90-110.
28. Durian D. J. Foam Mechanics at the Bubble Scale. Physical Rev Let. 1995;75(26):4780-4783.
    CrossRef
29. Krasaekoopt W., Bhatia S.Production of Yogurt Powder Using Foam-Mat Drying.  Assumption Univ Tech Jour. 2012;15(3):166-171.
30. Nimitkeatkai H., Potaros T. Effect of Foaming Agents on Properties of Instant Pumpkin Soup Powder Using Foam Mat Drying. Sci Tech Jour. 2020;28(5):790-798.https://doi: 10.14456/tstj.2020.64
31. Hirunyophat P. Substitution of Sugar with Stevia Extract in Chock – Anan Raw Mango Juice through Pasteurization Process. Christian Univ Jour. 2022;28(4):100- 110.
32. Heinonen M. I. Carotenoid and Provitamin A Activity of Carrots (Daucus carota L.) Cultivars. Agri Food Chem Jour. 1990;36:609-612.
    CrossRef
33. Herawati E. R. N., Febrisiantosa A., Ningrum A., Hendrasty H. K., Suppavorasatit I., Santoso U. Physicochemical and Functional Characteristics of Egg White Powder as Affected by Pre-Treatment and Drying Methods. Food Res Jour. 2024;8(5):365-372 https://doi.org/10.26656/fr.2017.8(5).178
    CrossRef
34. Azhuvalappil Z., Fan X., Geveke D. J., Zhang H. Q. Thermal and Nonthermal Processing of Apple Cider: Storage Quality under Equivalent Process Conditions. Food Qual Jour. 2010;33(5):612-631. 4557.2010.00342.x
    CrossRef
35. Carbonell-Capella J. M., Buniowska M., Cortes C., Zulueta A., Frigola A., Esteve M. Influence of Pulsed Electric Field Processing on the Quality of Fruit Juice Beverages Sweetened with Stevia rebaudiana. Food Biop Proc Jour. 2017;101:214-222. https://doi:10.1016/j.fbp.2016.11.012.
    CrossRef
36. Onsamlee G. Use of Stevia Extract in Coconut Milk Pudding. Thai Sci Tech Jour. 2019;28(6):1075-1085. https://doi: 10.14456/tstj.2020.85
37. Yildiz M., Karhan M. Characteristics of Some Beverages Adjusted with Stevia Extract, and Persistence of Steviol Glycosides in the Mouth after Consumption. Inter Gas Food Sci Jour. 2021;24:100326. https://doi:10.1016/j.ijgfs.2021.100326
    CrossRef

Abbreviations

CMC carboxymethyl cellulose

GMS glyceryl monostearate

SBI soybean isolate

CRD completely randomized design

RCBD randomized complete block design

ANOVA analysis of variance

DMRT Duncan’s new multiple range tests