Pumpkin, one of the most famous cultivars from Cucurbita moschata, is a rich source of carotenoid. However, having high water content (above 80%) makes pumpkin extremely perishable, and difficult to be processed and stored. Therefore, pumpkin needs a dehydration process in which could remove moisture content from the product but still able to uphold its natural color and minimum nutrient losses. We have carried out a comprehensive study to investigate the effect of different methods; sunlight drying (SD), cabinet drying (CD), and pneumatic drying (PD) on the physicochemical properties of pumpkin powder. The pneumatic dryer used was self-fabricated with a stainless steel plate (3 mm thickness) that has a total dimension of 1600x 500x 2500 mm. The physicochemical properties evaluated include final moisture content, the color difference (ΔE), carbohydrate, fat, protein, and β-carotene. CD produced powder with the lowest final moisture content. The mean value of ΔE of PD was the lowest as compared to SD and CD. The SD sample has the lowest mean FM value. Pneumatic drying exhibit good potential to produce pumpkin powder while retaining its color and nutritive values.

Purple yam (Dioscorea alata) is a type of plant that grown in almost all regions of Southeast Asia. In Indonesia, purple yam is one of the most popular types of sweet potatoes compared to other types of the genus Dioscorea. Purple yum is usually consumed directly as a side dish, or processed into a powder. One important process of making purple yam powder is drying. In this study, the characteristics of purple yam powder were evaluated from several drying methods, namely sunlight drying (SD), cabinet drying (CD), and pneumatic drying (PD). The pneumatic dryer used was self-made with a stainless steel plate (3 mm thickness) and has total dimension of 1600x 500x 2500 mm. The results showed that the CD sample had the lowest water content. The purple yam powder by CD and PD can produce brighter powder compared to that with SD method. From the FM test, the smallest FM value was obtained from CD sample. CD sample proven to be able to retain purple yam nutritive values after drying process.

Arrowroot (Maranta arundinacea) is a large herb found in rainforest habitats. In Indonesia, Arrowroot (or known locally as Ubi garut) is usually processed into a powder ingredient for many foods such as puddings and cookies. One of the crucial processes in producing arrowroot powder is drying. In this study, the effect of various drying methods on the characteristics of arrowroot powder was evaluated. They were solar drying (SD), cabinet drying (CD), and pneumatic drying (PD). The pneumatic dryer used was self-made with a total dimension of 1600×500×2500 mm. It was made from stainless steel plate with 3 mm thickness and equipped with heater, blower, feeder, cyclone, and drying chamber (heater fins of 4,500 watts). The moisture content showed that the CD sample has the lowest moisture content than other methods. The PD has a great potential to be used to produce arrowroot powder while retaining its color and nutritive values.

Jackfruit (Artocarpus heterophyllus Lam.) and snake fruit [Salacca zalacca (Gaert.) Voss] are tropical fruits that are rich in vitamins and minerals. Due to their specific aroma and unique taste, jackfruit and snake fruit have great potential to be processed into dried fruits and healthy snacks. In this work, jackfruit and snake fruit were freeze-dried using a self-designed laboratory-scale freeze dryer. The freeze dryer was constructed with a stainless-steel plate (3 mm thickness). The drying rates were determined with three different heating temperatures: 50, 60, and 70ºC. This study also investigated the effect of the freeze-drying process on the characteristics of dried fruit such as moisture content, texture, color, ascorbic acid content, and morphological of dried samples. Results showed that the heating temperatures were revealed to affect characteristics such as drying rate, final moisture content, texture, and ascorbic acid content. Increased drying rate and decreased drying time were observed with an increase in the dryer temperature. The sample resulted from 70ºC of heating temperature exhibited the optimum results in terms of hardness and ascorbic content preservation. The first-order kinetic model was the best fit for the prediction of drying kinetics of all materials.

One of the problems faced by corn farmers in Indonesia is the unavailability of corn dryers during rainy season. As the result, seed production decreased both in terms of quantity and quality. This study aims to design and introduce a bed seed dryer. Bed dryers are considered since it is simpler and cheaper. The dryer is designed for a capacity of 500 kg of corn, with corn cobs with a gasification combustion system as its fuel. This study also compared the effect of bed drying and sun drying (with two different floor materials; tarpaulin mat and concrete base) on dried-corn germination rate. The results showed that the designed dryer was able to reduce the moisture content from 22% (w.b.) to 14% (w.b) for 30 hours. The drying temperature is kept below 43°C and had no significant difference with the drying temperature of the sun drying. The germination rate of all samples has met the National standard for corn seed (SNI 01-03920-1995), which was 92%. The self-fabricated bed dryer has the potential to dry corn seed as good as using sun while retaining its quality.

Nowadays, coffee has become one of the most favorable commodities for beverages, flavoring as well as for cosmetic industries. In Indonesia, coffee becomes more popular, especially among youngsters. In this study, the spray drying process was evaluated, giving the potential of how simple spray dryer can help local farmers of Indonesia to produce their coffee powders. One small scale of spray dryer was constructed with the total dimensions of 2.85 x 0.64 for length x width, with a height of 2.32 m. The spray dryer was equipped with a digital thermo regulator, the pneumatic nozzle system, and 4 finned heaters with the power of 2700 watt for each. The spray drying constructed was revealed to be able to produce coffee powders with fine quality. The inlet temperature of the drying chamber, as well as the initial Brix content of feed solution, were proven to affect the physical properties of powder produced such as moisture content, product yield, and solubility. The final moisture content of powders was ranged from 3 - 7% db, with the high product yield of the drying process, which could reach up to 70%.

Edamame (Glycine max. L. Merill) has been consumed due to its savory taste and high nutrient content. The Edamame can be dried and consumed as a crunchy snack through the freeze-drying process. However, this drying method has its drawbacks, such as a decrease in shrinkage ratio. One of the solutions to this is by blanching treatment before the freeze-drying process. This study aimed to investigate the effect of blanching pre-treatment on the quality of freeze-dried edamame. The properties assessed include moisture content, color, texture, shrinkage ratio, protein content, chlorophyll content, and morphology examination. Fresh edamame with the initial moisture content of 70% w.b. was introduced to the variation of steam-blanching and water-blanching before the freeze-drying process. Each blanching was done for 3, 9, and 15 minutes. The laboratory freeze-dryer used in this study was constructed with a stainless-steel plate (3 mm thickness) and had total dimensions of 1.0 x 0.8 x 1.0 m. The blanching treatment was proven to help promote the product quality, such as a higher shrinkage ratio (p < 0.05) and retain protein and chlorophyll content during the drying process. Hot-water blanching treatment was justified to be better than steam blanching treatment, gave the lowest final moisture content ranged from 3 -6% d.b. Hot-water blanching also gave better results in terms of textural analysis and chlorophyll retention. The consumer acceptance test showed that freeze-dried edamame with hot-water blanching treatment gave a higher mean liking score than that with steam blanching treatment.

Natural hydrocarbon compounds are extremely in high demand across various applications. For instance, squalene (SQ) is widely used in cosmetic and food supplement industries, due to beneficial health components. The aim of this study was to investigate the potentials of antioxidant addition on the physical properties, as well as SQ stability in spray-dried powder at various oil droplet diameters (0.3 – 4 µm). Rosemary oil extract served as antioxidant, while iron (II) sulfate accelerated the oxidation. Subsequently, SQ stability was evaluated at four separate temperatures, termed 25, 50, 70, and 105°C, after one month storage. Also, the morphological structures of the samples were characterized with scanning electron microscopy (SEM). The results showed the oil droplet diameter influenced the physical properties of SQ, as lesser drip sizes were known to enhance material strength. Furthermore, antioxidant inclusion proved to be effective in inhibiting oxidation, particularly in powders with extensive oil droplet diameter. Therefore, high regression coefficients (R2 > 0.97) and reduced chi-square confirmed Weibull model acceptance in predicting the retention of SQ content.