Optimization of spray drying parameters for custard apple (Annona squamosa L.) pulp powder development using response surface methodology (RSM) with improved physicochemical attributes and phytonutrients

Abstract

Custard apple (Annona squamosa L.) is a highly perishable fruit, possessing enormous phytochemicals and nutrients with potential antioxidant, antimicrobial and anti-cancerous properties. In the present investigation, spray drying parameters were optimized to produce custard apple pulp powder (CAPP) using response surface methodology (RSM). The drying was carried out in a laboratory spray dryer at different levels of inlet air temperature (100–140 °C), outlet air temperature (70–110 °C), and maltodextrin (MD) concentration (10–20 g/dL). The optimized condition comprised an inlet temperature of 135 °C, outlet temperature of 75 °C, and the maltodextrin content of 15 g/dL, respectively. Under this optimized condition, the maximum powder yield of 14.8 g/dL with moisture content of 5 g/100 g was obtained. The bulk density, yield, degree of caking, solubility index, and dispersibility were significant (p < 0.05) in optimized CAPP. Further, scanning electron microscope (SEM) analysis revealed the amorphous behavior of spray-dried CAPP, showing minimum hygroscopicity. The differential scanning calorimetry and thermal gravimetric analysis of CAPP revealed better stability with a glass transition temperature of 200 °C, making it suitable at commercial and domestic level. The HPLC analysis of CAPP revealed the presence of phytonutrients like lutein and zeaxanthin having antioxidant and anti-diabetic properties.