Physicochemical and functional properties of microcapsules of papaya seed extract (Carica papaya L.) obtained by spray drying

Papaya seeds (Carica papaya L.) are usually discarded, yet they contain significant amounts of bio-components such as polyphenols, which are beneficial in the food and pharmaceutical industries. In this research, microcapsules from papaya seed extract were obtained through spray drying; the influence of the inlet temperature to the sprayer (130 °C, 140 °C, and 150 °C) and the concentration of the encapsulating agent, chitosan (0.5% and 1%), on their functional properties (polyphenols, antioxidant capacity) and physicochemical properties (moisture content, bulk density, hygroscopicity, solubility, and yield) was evaluated. The extraction of polyphenols was performed by ultrasound-assisted extraction using 50% ethanol; this extract was then concentrated under vacuum and microencapsulated. The most effective treatment was at an inlet temperature of 150 °C and a chitosan concentration of 0.5%, resulting in microcapsules with a high content of polyphenols and antioxidant capacity (97.6 Gallic Acid Equivalent – GAE/100 g dry sample and 413 mg Trolox Equivalent – TE/100 g dry sample, respectively). Under these conditions, 92.1% of the maximum antioxidant capacity was preserved in the microcapsules obtained from the papaya seed extract. The physicochemical properties were influenced by the studied factors: inlet temperature to the dryer and chitosan encapsulant concentration. These micro-encapsulated products could be a suitable alternative for applications as natural food additives with potential antioxidant activity, warranting further research.