Tarwi okara (Lupinus mutabilis) native and modified by high-intensity ultrasound as a gluten-free bread improver

Huamaní-Perales C.; Vidaurre-Ruiz J.; Cabezas D.M.; Correa M.J.; Burbano J.J.; Rodríguez-Soto J.C.; Repo-Carrasco-Valencia R. · Food Hydrocolloids (2025) · DOI: 10.1016/j.foodhyd.2025.111131

Resumen

Tarwi is an Andean leguminous rich in proteins and lipids. The extraction of lipids and proteins in alkaline conditions led to a by-product called okara which is rich in fiber and insoluble proteins. Thus, it could act as a hydrocolloid. To expand its range of applications in food production, eco-friendly technologies can be applied to improve the techno-functionality of this by-product. Therefore, the aim of this study was to evaluate the potential use of tarwi okara (native and sonicated) as a gluten-free bread improver. Both okaras were characterized by their compositional, structural, and technological properties. The interactions between the ingredients in dough matrices were observed using confocal laser scanning microscopy. Breads were evaluated through technological quality parameters. Results showed that the sonication process induced significant changes in tarwi okara, which mainly included a reduction in protein content and an increase in fiber content, as well as improvements in the techno-functional properties particularly desirable in bread products (water absorption capacity and emulsion activity). These properties influenced the consistency of doughs, whose micrographs confirmed the presence of dense matrices composed of dispersed starch granules surrounded by proteins and fiber fragments. Gluten-free breads prepared with the addition of 5% native sample or 3% sonicated sample exhibited specific volumes, crumb softness, and alveoli structures comparable to those of the control containing xanthan gum (0.5%). Hence, tarwi okara has great potential as a gluten-free bread improver. The relevance of this application lies in the circular economy framework and the growing interest in the development of clean-label food products.

Instituciones: Universidad Nacional de Trujillo; Universidad Nacional Agraria La Molina