Antioxidant and antibacterial effects of natural phenolic compounds on green composite materials

Abstract

The aim of this study is to establish the thermal characteristics of a biocomposite (Arbofill kokos®), stabilized with different natural phenolic additives, in order to check the antioxidant capacity of the resulting compounds on the biocomposite. The phenolic compounds used were thymol, carvacrol, α-tocopherol and tannic acid, and the concentrations used were 0.5wt% and 2wt% of each compound. The results obtained were compared with the same biocomposite stabilized with an industrial antioxidant agent (octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate). Thermo-analytical techniques were used (DSC and TGA) to carry out the study. The antimicrobial effect of these natural phenolic compounds on the biocomposite was also studied by analyzing of the growth of bacterial colonies. The comparison between the phenolic compounds and the industrial compound showed good antioxidant action of the phenolic compounds on the base biocomposite; in all the mixtures of biocomposite and antioxidant agent the oxidation onset temperature (OOT) of the biocomposite increased. Of all the phenolic compounds studied the highest OOT was achieved with α-tocopherol, which, compared with the temperature of the base composite, showed an increase of almost 45%.

On the Use of Gallic Acid as a Potential Natural Antioxidant and Ultraviolet Light Stabilizer in Cast-Extruded Bio-Based High-Density Polyethylene Films

“…In particular, some authors have reported similar results with other natural antioxidants [62,63]. For instance, España et al [64] showed that the incorporation of phenolic compounds successfully improved the T deg values of green composites made of a mixture of lignin and organic coconut fibers (CFs) with an excellent stabilization provided by tannic acid.…”

Effect of Poly(Lactic Acid)/Kenaf Composites Incorporated with Thymol on the Antimicrobial Activity of Processed Meat

“…Another study of a commercial lignin‐based material Arbofill kokos® containing short coconut fibers and 2% w/w thymol, a common AM agent, showed significant inhibition of Gram‐positive S. aureus after 20 h incubation although no AM activity against Gram‐negative bacteria, E. coli , was observed (España et al . ).…”

Enhancing the Thermal Stability of Polypropylene by Blending with Low Amounts of Natural Antioxidants

“…The melt stability of polyolefins has been widely studied by testing the typical thermal processing conditions controlling the melting atmosphere under limited oxygen . Several traditional synthetic antioxidants have been used as useful additives to protect the polymeric matrix during processing in really small amounts (i.e., between 0.1 and 0.3 wt%) . Most of the natural occurring antioxidants are polyphenolic compounds derived from flavonoids, which are gaining considerable interest in the plastic processing industry to replace the traditional synthetic antioxidants used for more environmental ones .…”

“…[8,15] Several traditional synthetic antioxidants have been used as useful additives to protect the polymeric matrix during processing in really small amounts (i.e., between 0.1 and 0.3 wt%). [16][17][18] Most of the natural occurring antioxidants are polyphenolic compounds derived from flavonoids, which are gaining considerable interest in the plastic processing industry to replace the traditional synthetic antioxidants used for more environmental ones. [8,9,13,14,16] For instance, Samper et al, processed PP with several NA and they demonstrated that flavonoids such as silibinin and quercetin provide better stabilizing effect to PP matrix than flavanone glycosides (i.e., hesperidin and naringin), providing stabilization effect similar to that provided by conventional petroleum-derived antioxidants, [14] typically used at industrial level, such as ethanox and Irganox.…”