Use of fruit epicarps to formulate pectin-based bioactive films / Utilização de epicarpos de frutos para formulação de filmes bioativos à base de pectinas

Abstract

The functional properties of biofilms can vary according to the biopolymer used as the raw material; thus, in the search for alternative sources for preparation of biodegradable films, fruits and vegetables have been used to extract compounds of interest with applications in the food industry. The objective of this work was to obtain and characterize bioactive films based on pectin extracted from the epicarps (skin) of the fruit. The genipap (Genipa americana), red pitaya (Hylocereus polyrhizus) and star fruit (Averrhoa carambola) were collected, washed, pulped and dried at 50 °C for 24 h, and their epicarps were ground and subjected to pectin extraction using the casting method. The films were characterized as to their visual appearance, moisture, pH, water solubility and antioxidant activity. The pectin-based films of G. americana and H. polyrhizus showed a yellowish color, while A. carambola was dark brown. The highest pectin yield (29%) and moisture content (13.9%) were obtained from the H. polyrhizus film, while A. carambola showed the highest solubility in water (98.6%) and had the highest pH (3.9). Additionally, the film based on A. carambola showed greater antioxidant potential against ABTS (30.5%) and DPPH (34%), as well as greater reducing power (0.262 absorbance at 750 nm) and content of total phenolic compounds (553 mg GAE/100 g), whereas H. polyrhizus had a higher percentage of chelating ability (27%). The physicochemical characteristics and bioactive properties exhibited make the film formulation a viable alternative for the food industry.