Avaliação tecnológica e sensorial da erva-mate (Ilex paraguariensis) durante a maturação: integração de análises colorimétricas e dinâmica fenólica

Abstract

Color is a determining sensory attribute in the plant-based product market, with the intensity of the green hue being the primary freshness parameter of yerba mate (Ilex paraguariensis) valued by consumers. During industrialization and the maturation period (resting), the use of objective instruments for color assessment is essential to reduce the subjectivity of empirical methods. This study aimed to validate the applicability of the Nix Quality Control (Nix QC) portable colorimeter in comparison to the industrial standard Konica Minolta CR-410, and to evaluate the physicochemical, phenolic, and sensory transformations of yerba mate over 12 months of natural maturation. In the first chapter, CIELAB color space parameters were analyzed across 219 batches, demonstrating high correlation between devices for the a* (r = 0.931) and b* parameters, validating the Nix QC as a technically viable alternative. In the second chapter, native yerba mate samples were monitored for moisture content, water activity, phenolic compound dynamics (via HPLC), and sensory profile (via Descriptive Analysis — DA). Results indicated a significant increase in moisture content (2.86% to 8.06%) and a progressive reduction in caffeine, theobromine, and free phenolic levels, attributed to oxidative reactions and polymerization. Sensory analysis revealed a clear transition from a "fresh-green" profile to a "mature" profile, characterized by golden coloration, straw-like notes, and increased astringency. Principal Component Analysis (PCA) confirmed the discrimination of samples at the final maturation stages (9 and 12 months). It is concluded that controlled maturation strategically modulates yerba mate quality, adding sensory complexity and stability, with instrumental monitoring serving as a fundamental tool for industrial standardization and premium market segmentation.