Quinoa malt and blueberry functional beverage: effect of malting and consumer sensory evaluation

Background: Consumers are looking for functional, natural products, valuing minimally processed, additive-free foods that include ancestral crops such as quinoa for their sustainability, nutritional quality and cultural connection. Objective: to evaluate the influence of processing on the antioxidant capacity and total phenolic compounds and consumer liking of a functional beverage based on quinoa malt (Chenopodium quinoa Willd.) and blueberry (Vaccinium corymbosum) pulp. Methods: Total phenolic compounds (TPC) were determined by ultraviolet-visible spectrophotometry (UV-Vis). The antioxidant capacity was determined by the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl1-picrylhydrazyl (DPPH) methods were applied. Consumer liking level was determined using a five-point verbal scale on 86 untrained evaluators. Results: The mixture design was employed with minimum-maximum constraints to obtain the optimized beverage formulation based on the blend of three types of quinoa malt [black quinoa malt (BQM), red quinoa malt (RQM), and white quinoa malt (WQM)]. The response variables were antioxidant activity using the DPPH and ABTS methods. Each of the response variables was maximized and fitted to the quadratic regression model. The optimum formula had 70% black quinoa malt (BQM), 20% red quinoa malt (RQM) and 10% white quinoa malt (WQM). Antioxidant capacity increased from stage to stage from 45.11 ± 0.26 µg TE/g in sprouted quinoa (SQ) to 767.55 ± 4.94 µg TE/g in quinoa malt-based beverage with the inclusion of blueberry pulp (QMB) using the DPPH method and from 271.64 ± 1.23 µg TE/g in SQ to 834.32 ± 2.14 µg TE/g in QMB using the ABTS method. The sensory evaluators rated QMB between "good" and "super good" according to the attributes of odor, color, taste and appearance, evaluated. Conclusions: Quinoa malting and fruit addition significantly influenced the antioxidant capacity and total phenolic compounds. Furthermore, the sensory characteristics of the beverage were described within the range of "good" to "super good" in the evaluated attributes.