Physicochemical properties and antioxidant capacity of oak (Quercus resinosa) leaf infusions encapsulated by spray-drying.

Abstract

The effect of two wall materials and two feed flow rates on the physical and antioxidant properties of Quercus resinosa leaf infusionmicroencapsulatedbyspray- dryingisreported. Dispersions withlyophilized Q. resinosa infusion andwallmaterial(k-carrageenan and maltodextrin [10DE])wereprepared.Sampleswerefedatrate flows of1.6and1.7L/h. Encapsulation yield, total phenolic content, DPPH test, deoxy-D-ribose assayt ,rheological and SEM evaluations were made. The highest yield and DPPH scavenging activity were obtained at 100% maltodextrin and 1.7 L/h .Higher polyphenolic retention was observed in blends of carrageenan/maltodextrin (1.6 and 1.7 L/h) and malto dextrin (1.6 L/h). The highest inhibition of deoxy-D-ribose oxidation was found at blends of carrageenan/maltodextrin (1.7L/h). Dispersions showed pseudo plastic be havior and properties as liquid-like materials. Microcapsules showed particle sizes between 5 and 35 mm. Thebest condition for encapsulation of Q. resinosa infusions was suggested as 100% maltodextrin at 1.7 L/h.