Characterization of active biodegradable onion-based films for use in meat products

Abstract

The growing demand for reducing the use of synthetic materials has promoted the use of biodegradable components, especially in the food industry, aiming to replace plastic packaging in food preservation. In this context, the development of biodegradable films has emerged as a promising alternative to conventional materials. This study evaluated and characterized two biodegradable films for application on beef hamburgers, one made from red onion and the other from white onion. After production, the films were analyzed for water vapor permeability, moisture content by infrared, mechanical properties, thickness, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), attenuated total reflectance infrared spectroscopy (ATR-FTIR), and antioxidant activity.The red onion film exhibited greater thickness at 38 mm (P<0.0001) and higher water vapor permeability of 2.61 PVA g·mm/m²·day·kPa (P=0.0055). In contrast, the white onion film showed better mechanical performance, with higher values of maximum force (32.5 N; P=0.0059), tensile strength (3.99 MPa; P=0.0165), and elastic modulus (37.9 MPa; P=0.0033). Thermogravimetric analysis revealed a higher residual mass in the white onion film (38.3% vs. 28.5%). The obtained spectra were similar but showed differences in band intensity—stretching and bending at various wavenumbers (cm⁻¹). The red onion film had superior antioxidant activity, with DPPH (%) at 85.7 (P=0.0029) and ABTS (%) at 63.8 (P=0.0213), likely due to its higher anthocyanin content. The greater thickness of the red onion film may enhance its role as a physical barrier, although the high water vapor permeability suggests a stronger influence of its internal structure. The superior mechanical properties of the white onion film are advantageous for handling and storage. Spectroscopic differences indicate variations in the concentration of bioactive compounds, without structural alterations. The films exhibited complementary characteristics, allowing for distinct applications depending on the type of food and packaging goals—whether for physical protection, mechanical strength, or antioxidant activity.