Corante natural da casca de pinhão (Araucaria angustifolia) e redução de temperatura de estocagem na qualidade mecânica de filme biodegradável

Abstract

Obtaining products that do not harm the environment is of paramount importance for society, considering the alarming increase in the production of plastic waste around the world. The food industry, in particular, is one of the largest generators of packaging, which although it plays a crucial role in extending the shelf life of food, its inadequate disposal represents a serious environmental problem. An emerging trend to address this challenge is the development of biodegradable films as a sustainable alternative to conventional plastic. In parallel, natural dyes emerge as a current topic in the area of food technology, both due to their appeal to human health and the environment. However, in the same way that a biodegradable film has a rapiddegradation process in nature, it also has a short useful life as packaging. Therefore, the investigation of procedures that can increase the useful life of the application becomes important. Within this context, the objective of the present research was to evaluate the effects of natural pine nut shell dye and temperature reduction on the recovery of the quality of mechanical properties of biodegradable films. of pine nuts) composed of glycerin, PBAT and cassava starch and stored at room temperature for 365 days were stored at temperatures of 0, -20 and -40 °C during a period of 90 days. Analyzes of mechanical properties were carried out, including tensile strength and elongation at break, in addition to colorimetric analysis using the CIELab method to evaluate color stability during the experiment. Furthermore, scanning electron microscopy analysis was conducted to verify the microstructural integrity of the films throughout the experimental period. The study evaluated the mechanical and colorimetric properties of newly manufactured biodegradable films and after one year of storage, finding that the initial values were higher. Deterioration over time was expected, but the films stabilized, especially at subzero temperatures. Freezing, particularly at -40 °C, improved and varied the elongation of the films. Films with natural pine nut shell dye showed significantly better elongation at break than control films, indicating that the dye also improved mechanical properties. After 365 days,the dyed films suffered colorimetric deterioration, but the a* component showed no significant difference in relation to the newly manufactured film. All colorimetric parameters changed significantly after the beginning of storage, stabilizing later. The ΔE variation was imperceptible to the naked eye at temperatures of -20 °C and -40°C, with greater stability observed at -40 °C. The electron microscopy images confirmed the stability of the films during the experiment, with no cracks or tears, just non-gelatinized starch granules, reinforcing the durability of the material under different storage conditions.