Chemical characterization of guarana seed coat and its application in plant-based burgers

Samples were transported to UNICAMP for analysis, ensuring regional representativeness. Access to genetic resources was registered in SisGen (A88A216), in accordance with Brazilian regulations. The material was milled (RENARD knife mill), reprocessed, and sieved (<0.35 mm) to obtain a standardized powder, and analyses were performed on the three guarana seed coat samples (PR1, PR2, and PR3).

Subsequently, four plant-based burger formulations were developed (Control, GB1, GB2, and GB3), all containing 75 g of plant protein per 100 g. Prior to formulation, the guarana seed coat was processed by extrusion using a co-rotating twin-screw extruder (ZSK 30, L/D 29:1, 25% moisture). It was then used to replace hydrated soy protein at levels of 0%, 17.5%, 25%, and 50%, while the remaining ingredients were kept constant.

The mixtures were homogenized, shaped into 100 g portions, ultrafrozen, and stored at −18 °C. Before analysis, the burgers were baked at 200 °C, homogenized, and stored again at −18 °C until further analyses.