Catarina Motta de Moura

This research explores the potential of a biopolymeric film as a colorimetric indicator to monitor pork freshness through pH changes. Jaboticaba epicarp extracts were obtained via maceration and analyzed for their total phenolic content, antioxidant activity, and total anthocyanin content. High‐performance liquid chromatography (HPLC) analysis identified cyanidin‐3‐glucoside as the most abundant phenolic compound in the extract. Although these bioactive compounds were characterized, they were not directly related to the color shift of the indicator, which occurred mainly due to pH increase during pork storage. Biopolymeric characterization revealed that the color difference ( Δ E ) of the sensor was 13.40 ± 0.69, a change readily perceptible by the human eye. The incorporation of the extract into the film matrix improved several properties, including thickness, water vapor permeability, tensile strength, and elongation at break. In addition, the nitrogen compounds released during pork storage were quantified, showing a progressive increase that correlated with the observed color change of the indicator. Overall, the biopolymeric film formulated with κ ‐carrageenan and jaboticaba epicarp extract demonstrated enhanced functional and mechanical properties, as well as reliable colorimetric responsiveness to pH variations, supporting its potential application as a sustainable indicator for monitoring pork meat freshness.

In this work, spouted bed and tray-drying techniques were employed at different drying air temperatures to produce dried chitosan, and the chitosan powder was used to produce biofilms. The products obtained from each drying technique were compared in relation to quality aspects (molecular weight, lightness, and hue angle). The results found for chitosan in spouted bed drying (90°C) showed lower alteration and best quality aspects in relation to the chitosan powder. However, in tray drying under the best condition (60°C) the chitosan molecular weight increased about 50% in relation to the initial value and browning was observed. The biofilms produced from chitosan dried in the spouted bed showed the best mechanical properties (tensile strength of 42 MPa and elongation of 29%) and lower water vapor permeability (3.95 g mm m⁻² kPa⁻¹ day⁻¹).