Filmes de amido de mandioca incorporados com ora-pro-nóbis e natamicina para o controle de fungos contaminantes de alimentos

Abstract

Pereskia aculeata is a native Brazilian plant that grows in several regions of the country. This plant stands out for its nutritional value, containing more than 20% protein in its dry matter. It is also rich in minerals such as iron, magnesium, and calcium, as well as phenolic compounds with antioxidant and antimicrobial properties, suggesting its use for nutritional enrichment and as a food additive. The plant contains mucilage in its leaves, stems, and fruits. This hydrocolloid is composed of arabinogalactan, with monosaccharides such as arabinose, galactose and galacturonic acid, as well as proteins. There are several studies evaluating the potential of P. aculeata biopolymers, with applications as food thickeners and gelling agents in the production of biodegradable films. In this context, the present dissertation aimed to produce films based on cassava starch, P. aculeata mucilage, through aqueous extraction, freeze-drying process (MPA)and use of natamycin, having evaluated their physical properties and in vitro antifungal activity. This study also included the compositional characterization of dehydrated leaves of P. aculeata (FPA) and MPA. The films were produced using starch (T1), starch and natamycin (T2), starch and 15% MPA (T3), and starch, natamycin, in addition, 15% MPA (T4). The films were evaluated for color properties, transparency, water solubility, swelling index, scanning electron microscopy (MEV), Fourier Transform infrared spectroscopy (FT-IR), and antagonistic activity against Penicillium sp. The composition of MPA has showed protein content similar to that of the dehydrated leaves (FPA), indicating that the protein fractions were preserved in the mucilage. MPA presented 65% total dietary fiber and a higher concentration of mineral residues compared to the dehydrated leaves. Treatments T3 and T4 exhibited darker coloration (ΔE of 67.36 and 59.85, respectively) compared to treatment T1, as well as lower transparency at wavelengths of 380nm and 600nm. The T4 sample has showed the highest solubility among the treatments. The T2 exhibited the highest swelling index. The FT-IR spectrum demonstrated that the association of starch with MPA altered the film structure more than natamycin alone. Treatments T2 and T4 exhibited antagonistic activity against Penicillium sp., which is attributed to the action of natamycin, with the lowest growth rate observed in T4. The spore germination rate of T2 and T4 samples immersed in BHI (Brain Heart Infusion Broth) liquid culture containing Penicillium sp. spores was less than 1% after 48 hours. The dissertation concluded that the coating film, composed of starch, 15% MPA and natamycin, proved to be a promising coating for controlling Penicillium sp., suggesting a possible application on food surfaces.