Effects of Stevia Syrup on Powdered Drink Products from Pumpkin Carrot and Lemongrass by Foam Mat Drying

One simple approach which allows water to be removed from blended fruits and vegetables is foam mat drying. In this process, the liquid sample is changed into foam form. The research was performed to study the production of pumpkin, carrot and lemongrass powder using both egg albumen and carboxymethyl cellulose (CMC) as the foaming agent and to determine the effects of different amounts of stevia syrup (0, 20, 30, and 50 mL) upon the foam mat drying qualities. Each treatment contained the ratio of pumpkin juice: carrot juice: lemongrass juice: salt as 55: 140: 55: 0.1. The foam was prepared from mixed pumpkin, carrot and lemongrass by adding two types of foaming agent (12g of egg albumen and 6 g of CMC) and whipping for 5 minutes. It was found that foam density, stability and overrun were significantly (p<0.05) influenced by the quantity of stevia syrup. 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 physicochemical and microbiological properties of the products included color, solubility, foam density, foam stability, moisture, water activity, moisture, protein, fat, ash, DPPH, β-carotene and total plate count. The sensory properties included the taste, texture, odor, color and general level of acceptability. The findings revealed that the physicochemical results were significantly different (p<0.05). A reduction in stevia syrup caused increasing in the protein, fat and ash values. For Treatment 4 produced the best results, the foam density, foam stability percentage, overrun percentage, and yield percentage were 0.72 g/mL, 72.25%, 80.59% and 15.29%, respectively. As the amount of stevia syrup decreased, the foam density also decreased, but the foam stability percentage, overrun percentage and yield percentage all significantly increased (p<0.05). The microbiological results revealed that the quality of the mixed pumpkin, carrot and lemongrass powder met the required safety standards. The sensory attributes of mixed pumpkin, carrot and lemongrass exhibited no significant difference (p>0.05) with the exception of taste, which was influenced by the amount of stevia syrup. The mixed pumpkin, carrot and lemongrass obtained from Treatment 4 required optimization in order to create the foam mat powder. It can therefore be argued that the approach of foam mat drying using egg albumen, CMC and stevia syrup is a food production technique worthy of further investigation.