. 2021 Dec 11;10(12):1976. doi: 10.3390/antiox10121976

Table 3.

Effect of natural active agent incorporation on mechanical properties of PLA films processed through different techniques.

Processing Technique	PLA/Active Agent	YM (MPa)	TS (MPa)	EB (%)	References
Melt blending-hot pressing	PLA control	3361	56.82	2.21	[32]
	Waste orange peel extract Rosemary ethanolic extract with or without chitosan	↓	↓	≈ or ↑	[32,55]
	Chitosan	↑	↑	↓	[55]
Cast extrusion	PLA control	3000	65	3.1	[51]
Cast extrusion	Allium spp. Extract Oregano essential oil Merkén	↓	↓	↓	[43,51,59]
Extrusion-stretching	PLA control	-	-	40	[48]
Extrusion-stretching	Thymol, R-(−)-carvone	↓	↓	↑	[48]
Blown extrusion	PLA control	-	40.2	3.63	[60]
Blown extrusion	Green tea extract	↓	↓	↑	[60]
Injection molding	PLA control	3100	52.7	2.9	[38]
Injection molding	Thymol and Carvacrol β-CD-thymol and β-CD-carvacrol	↓	↓	↑	[38,52]
Casting	PLA control	1702	45.8	5.4	[49]
	Clove essential oil Bergamot, lemongrass, rosemary and clove Ethanolic extract of propolis	↓	↓	↑	[13,49,61]
	Allyl isothyocianate Wild garlic	↓	≈ or ↑	≈ or ↓	[31,44]
Electrospinning	PLA control	-	12.24	57.28	[58]
	Tea polyphenol Propolis powder extract	↓	↓	↓	[58,62]
	Propyl gallate	↓	↑	↑	[57]
Supercritical impregnation	PLA control	1607	47.9	3.4	[46]
	Thymol	↓	↓	↑	[15,46]
	Cinnamaldehyde	≈	↓	↑	[17,18]

YM: Young’s modulus. TS: tensile strength. EB: elongation at break. Trends: ↑ (increase), ↓ (decrease), ≈ (invariable). The hyphen indicates that the mechanical parameter or its units were not reported.