Effect of Acidification on the Properties of Films Developed from Carboxymethylcellulose and Jabuticaba Anthocyanin Extract (Plinia Cauliflora)

This study evaluates acidification as a formulation strategy in carboxymethylcellulose (CMC)-based films incorporating anthocyanins extracted from jabuticaba peel (Plinia cauliflora), aiming to develop intelligent and biodegradable materials for food packaging. To the best of our knowledge, anthocyanins derived from jabuticaba peel have not previously been incorporated into CMC-based film systems, particularly with a systematic assessment of formulation acidification. Three film formulations were prepared: a control film (FC, pH 6), a nonacidified film containing anthocyanins (FSA, pH 5), and an acidified film containing anthocyanins (FCA, pH 3), allowing the effects of anthocyanin incorporation and matrix acidification to be evaluated independently. Spectrophotometric analysis confirmed the pH-responsive behavior of the anthocyanins, with acidification promoting a deeper red hue and improved chromatic stability. Anthocyanin incorporation increased film thickness and reduced tensile strength and elastic modulus, while Fourier-transform infrared spectroscopy indicated interactions between anthocyanins and the CMC matrix. Importantly, thermal stability was maintained, and acidification significantly enhanced color intensity without compromising thermal properties. Overall, these findings support the potential application of the developed films in solid or semisolid food packaging systems.