COMPARISON BETWEEN THE USE OF GLYCEROL OR SAFFLOWER OIL AS A PLASTICIZER IN THE ANTIOXIDANT PROPERTIES OF CHITOSAN FILMS INCORPORATED WITH ACEROLA EXTRACT

Biofilms made from biodegradable matrices have the potential to replace non-biodegradable plastics in the food packaging industry. The objective of this study was to compare the effect of glycerol (GL) and safflower oil (SO) as plasticizers, at 1% v/w on the antioxidant properties of chitosan biofilms incorporated with acerola extract (AE) at concentrations of 1, 2 and 2.5% v/w, at storage times D-0 and D-15. Since the SO has stabilizing capacity, provides protection and can be a vehicle of bioactive compounds, it was chosen to be used as a potential GL substitute. Biofilms with GL (BGL) and SO (BSO) were elaborated by casting and stored for 15 days. Analysis of phenolic content, antioxidant capacity by DPPH, color, thickness and opacity were conducted. At D-0, the antioxidant activity of BGL ranged from 18.84-28.21%, with 21±2.59% reduction at D-15. BSO, at D-0, presented antioxidant activity between 20.65-30.68%, with 17.06±2.38% reduction at D-15. Similar behavior occurred in phenolic: BGL presented lower values (0.0711±0.01 and 0.0559 ± 0.01 mg/mL in D-0 and D-15) and phenolic retention than BSO (0.0814±0.02 and 0.0687±0.01 mg/mL in D-0 and D-15). These results can be attributed to the presence of tocopherol and phenolic compounds in SO and its ability to stabilize and protect natural compounds from AE. BSO presented lower values of L* (79.76±1.32%) and C (4.61±0.50%) and higher thickness (0.08±0.02 mm), opacity (6.74±1.06) and h(º) (110.02±4.21º) than BGL: L* (84.75±1.74%), C (10.03±0.80%), thickness (0.03±0.01 mm), opacity (4.14±0.30) and h(º) (95.06±0.66°) at D-15, indicating that SO addition makes them darker, saturated, opaque and greenish, due to SO yellow-green coloration and to the fact that oily substances form a dispersed phase, with heterogeneous distribution during the films drying. The SO plasticizer improved the antioxidant properties of BSOs, making them opaque, thick and dark, suitable for packaging foods with photosensitive compounds.