CHARACTERIZATION OF GERMINATED ANDEAN GRAIN FLOURS AND COCOA HUSK FOR THE DEVELOPMENT OF GLUTEN-FREE PRODUCTS

The demand for gluten-free functional foods has driven the search for alternative ingredients with high nutritional value and suitable technological properties. Andean grains such as quinoa and kañiwa are characterized by their high protein content and bioactive compounds, while cocoa husk is a coproduct rich in dietary fiber and phenolic antioxidants. The objective of this study was to characterize the physicochemical and technofunctional properties, bioactive compound content, and antioxidant capacity of quinoa and kañiwa flours (ungerminated and germinated) and cocoa husk, in order to provide a scientific basis for their use in the development of gluten-free foods. Germination was performed under controlled conditions, and the flours were obtained by drying (50 °C), milling, and sieving (150–200 µm). Proximate composition, water absorption capacity (WAC), water retention capacity (WRC), water solubility index (WSI), swelling power (SP), oil absorption capacity (OAC), total soluble phenolic compounds (TSPC), total flavonoids (TF), antioxidant capacity by ABTS, and tannin content were evaluated. Data were analyzed using ANOVA and Tukey's test (p < 0.05). Germination increased WAC (3.23 and 3.42 g/g for germinated quinoa and kañiwa, respectively) and WSI (26.28% and 23.57%, respectively). Cocoa husk presented the highest WRC (3.96 g/g), protein (23.86%), and dietary fiber (42.50%) values. Regarding bioactive compounds, cocoa husk showed the highest values of TSPC (2160.37 mg GAE/100 g), TF (859.38 mg QE/100 g), ABTS (11371.8 µmol TE/100 g), and tannins (4343.79 mg CE/100 g). Germination increased TSPC in quinoa (from 221.83 to 771.37 mg GAE/100 g) and kañiwa (from 452.87 to 812.10 mg GAE/100 g), as well as antioxidant capacity measured by ABTS (from 726.96 to 1975.36 µmol TE/100 g in quinoa and from 825.28 to 2979.17 µmol TE/100 g in kañiwa). However, germinated quinoa presented the lowest tannin content (46.64 mg CE/100 g). The increase in TSPC and TF is attributed to the activation of phenylalanine ammonia-lyase during germination, which catalyzes the de novo synthesis of antioxidant secondary metabolites, as well as to the action of hydrolytic enzymes that release flavonoids bound to the cell wall. The reduction in tannins, in turn, may be attributed to the activation of tannase and endogenous polyphenol oxidases, which degrade high-molecular-weight tannin polymers, thereby reducing astringency and improving protein digestibility and mineral bioavailability. Cocoa husk stood out for its richness in flavan-3-ols (epicatechin, catechin, and procyanidins), positioning it as an exceptional bioactive matrix. These results confirm the potential of germinated Andean grain flours and cocoa husk as functional ingredients for gluten-free products, offering improved technofunctional properties and an enhanced bioactive compound profile.