Technological properties and enhancement of antifungal activity of a Paeonia rockii extract encapsulated in a chitosan-based matrix

• Microencapsulation of Paeonia rockii extract (PPR) in a spray dried chitosan (C) matrix.
• 0.5% w/v C and 1/1 C/PPR ratio led to high process yields (70.1%).
• The microencapsulation process led to high encapsulation efficiency (82.4%) and low dimensional distribution (5.15 μm).
• The produced powder (C-PPR) showed enhanced water dissolution properties and storage stability with respect to PPR.
• C-PPR exhibited antioxidant property and enhanced antifungal activity against Candida albicans with respect to PPR.

The present study reports on the encapsulation of a polar extract from Paeonia rokii (PPR) with antioxidant and antifungal activity by spray drying technique using chitosan (C) as polymeric matrix. The influence of the process and of the coating agent on the encapsulation, storage stability, technological and functional properties of microencapsulated PPR was evaluated towards the unprocessed PPR. The combination between chitosan and PPR in term of antifungal activity was also examined. The selected 0.5% w/v chitosan concentration and all tested C/PPR ratios (1:1; 2:1; 3:1) led to a satisfactory process efficiency in term of yield (ranging from 69.8% to 73.2%), encapsulation efficiency (ranging from 80.1% to 84.9%) and particle size (ranging from 5.15 to 9.28 μm). The formulation produced starting from 1:1 C/PPR ratio (C-PPR/1), showed the highest polyphenol content (APC 6.63%) with respect to the other formulations. Due to the correlation between polyphenol content and functionality of PPR, C-PPR/1 was chosen for the successive studies. The C-PPR/1 powder resulted stable and handling also showing high water dissolution rate with respect to the unprocessed PPR. Interestingly, the combination of chitosan and PPR extract was able to enhance the antifungal activity comparing to raw extract, suggesting a potential synergy in the action or enhancement of bioavailability of the antimicrobial molecules. The made-up powder resulted in a functional component that can be used with great potential in foods, cosmetics or nutraceutical products.