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

• Maltodextrin are better wall material than k-carrageenan to obtain high yield.
• Wall material and feed flow have influence on the phenolics retention.
• High antioxidant activity is obtained at high feed flow in spray-drying phenolics.

The effect of two wall materials and two feed flow rates on the physical and antioxidant properties of Quercus resinosa leaf infusion microencapsulated by spray-drying is reported. Dispersions with lyophilized Q. resinosa infusion and wall material (k-carrageenan and maltodextrin [10 DE]) were prepared. Samples were fed at rate flows of 1.6 and 1.7 L/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 maltodextrin (1.6 L/h). The highest inhibition of deoxy-d-ribose oxidation was found at blends of carrageenan/maltodextrin (1.7 L/h). Dispersions showed pseudoplastic behavior and properties as liquid-like materials. Microcapsules showed particle sizes between 5 and 35 µm. The best condition for encapsulation of Q. resinosa infusions was suggested as 100% maltodextrin at 1.7 L/h.