Optimization of Process Parameters for Foam Mat Drying of Coconut Inflorescence Sap

Abstract

Coconut inflorescence sap (palm nectar) is a rich source of sugars, vitamins, minerals, and micronutrients. As coconut inflorescence sap ferments quickly due to microorganisms, converting it into a powder form would enhance its accessibility and availability for longer durations. This study investigated the effects of foaming process parameters, such as egg albumin concentration and whipping time, on foam expansion and foam density. In addition, the physicochemical properties, including water activity, bulk density, water absorption index (WAI), water solubility index (WSI), pH, ascorbic acid, acidity, reducing sugar, phenolic content, and protein content of foam mat dried coconut inflorescence sap, were also measured. A central composite design was employed to create linear regression equations for each response and to optimize the process parameters. It was observed that a stable foam was produced using the foam mat drying process that facilitated quick drying and retained the nutritional quality in the dried powder. The optimum conditions for the foaming process, while retaining physiochemical and nutrient properties, were found to be 5% concentration of egg albumin and a whipping time of 10 min. Under these optimal conditions, the ascorbic acid content, acidity, reducing sugar, total phenolic content, and protein content of coconut inflorescence sap powder were 2.38±0.05 mg/100mL, 0.20±0.01 %, 13.2±0.38 %, 2.3±0.05 CE/g, and 21.9±0.39 mg/100mL, respectively. The results indicate that foam mat drying is a viable option to increase the shelf life and retain the nutritional value of coconut inflorescence sap.