Produção, caracterização e potencial industrial do aditivo natural Hyssopus officcianalis l. no desenvolvimento de membranas biodegradáveis

Abstract

The quest to minimize the consumption of fossil-based and non-biodegradable plastic materials has driven the development of innovative materials from renewable resources. The use of natural additives, such as essential oils, in the development of biodegradable films is proving to be effective as antimicrobial, antifungal and antioxidant agents. Hyssop is used as a condiment, natural medicine and produced as an essential oil. It has antimicrobial, antifungal, antispasmodic, antiseptic, antiviral and antioxidant properties, which are widely used in the field of natural medicine. With a view to its applicability in biopolymeric films area, the aim of this work was to produce and characterize biodegradable membranes with Hyssop essential oil, analyzing their possible industrial potential and presenting sustainable methodologies. Films made from cassava starch were developed using the casting method. The characteristics of the films containing Hyssop essential oil and Clove and Oregano essential oil were compared. For the control test (T0), the concentrations and names of clove, hyssop and oregano essential oils in cassava starch films were (TC05=0.5%, TH05=0.5%, TO05=0.5%) and (TC1=1%, TH1=1%, TO1=1%). To improve the characteristics of the membranes, cassava starch films were also produced with different concentrations of bentonite nano-clay, added with hyssop essential oil. The concentrations and names of the nano-clay were (B1=0.1g; B2= 0.2g; B3=0.3g, B4=0.4g), and with the addition of 1% Hyssop essential oil (HB1=0.1+1%, HB2=0.2+1%, HB3=0.3+1%, HB4=0.4+1%). In all productions, 30% plasticizer (glycerin) was added and 3.0g of cassava starch was used. The properties of thickness, density, color, opacity, water vapor permeability, water solubility, contact angle, tensile strength, elongation, and microstructures were evaluated by scanning electron microscopy, Fourier Transform Infrared Spectroscopy, UV-Vis Spectroscopy, their thermal properties by Differential Scanning Calorimetry and Thermogravimetry, and their biodegradability in soil. In cassava starch membranes, the use of Hyssop essential oil showed significant results of 65% elongation, proven antimicrobial activity against Staphylococcus aureus ATCC 43300, water solubility (41, 78%, for TH05), high luminosity (L*= 94.56±0.82 for TH1, low opacity (37.53%, for TH05) and the second shortest biodegradation time in soil (175.15 days, for TH1), calculated by the linear regression method. Despite the addition of essential oils, the films showed hydrophilic characteristics. The films with added bentonite showed improved mechanical properties, such as tensile strength, protection against UV rays and considerable transparency in the Visible region. The hydrophobic characteristics of hyssop essential oil caused low water vapor permeability (HB1=4.45±0.82 g mm/m²diaKpa). The addition of the natural additive had a positive influence on the films' luminosity (L*=92.04±0.33 for HB1) and a reduction in their opacity (HB2=44.06%). Tests HB1 and HB4 showed inhibition against Enterobacter aerogenes. Tests B3, HB3 and HB4 showed significant loss of mass through biodegradation. The membranes showed exothermic properties. All the samples produced in this work showed porous microstructures. Hyssop essential oil is relevant as a natural additive in biodegradable membranes, and that the films produced have significant industrial potential and could therefore be a substitute for synthetic films. With this in mind, the films produced, T0; H1; HB1; B1; HB4 and B4 were applied to chilled fresh beef, analyzing their behavior as a substitute for synthetic packaging during a seven-day shelf life. The treatments were tested for color, water activity (Aw), texture (kgf) and mass loss (%). The tests resulted in films that had a change in color, but did not show low attractiveness. The films caused a loss of Aw in the beef samples (H1=0.447aw), followed by a loss of mass (HB4=68.07%) and dried meat samples with rigid textures. Despite the results found, the membranes with OEH showed antioxidant action, preventing lipid oxidation and thus controlling the proliferation of bacteria and fungi, while maintaining a pleasant appearance and smell of the beef.