3G extruded snacks enriched with catechin for high antioxidant capacity.

Extrusion yields either an expanded product or a non-expanded pellet. Non-expanded pellets undergo subsequent indirect expansion in a separate thermal device, such as a microwave oven, resulting in a third-generation (3G) snack. The utilization of milder conditions, makes this an encouraging approach for functional food development. Currently, the effects of both processes on retaining functional ingredients and the evolution of their structure are not yet fully understood. Accordingly, this work aimed to analyze how extrusion temperature (110, 135, and 150 °C) and moisture content (27 and 31%) affect the physical characteristics of 3G expanded rice-flour products enriched with catechins, using a microstructural approach, to better understand the relationship between catechin retention, antioxidant capacity, and structure development. The results showed that products with catechin exhibited higher expansion and increased crispiness/crunchiness, with a relatively higher percentage of small pores, as revealed by X-ray microtomography. Additionally, there was a remarkable retention of catechin and antioxidant capacity (DPPH) in the expanded products, reaching nearly 100%. The preservation of antioxidant capacity in the expanded products may be attributed to the high-temperature-short-time process, which favors catechin stability, along with the dense glassy structure of the extruded pellets obtained, protecting them through encapsulation until their subsequent expansion. [Display omitted] • 3G expanded rice-flour extruded pellets enriched with catechins were analyzed. • Lowest moisture and higher extrusion temperature led to higher expansion. • Catechin improved expansion and crispness/crunchiness. • Catechin retention and antioxidant capacity in expanded products neared 100%. • The dense glassy structure of pellets might preserve catechins. [ABSTRACT FROM AUTHOR]