Poly (lactic acid) and its improved properties by some modifications for food packaging applications: A review

The development of green and ecologically balanced food packaging materials is a major concern for the food packaging industry, which is highly dependent on non-biodegradable petroleum-based products. Polylactic acid (PLA) is known as a promising biopolymer that can be used for food packaging due to its high mechanical strength and properties of tensile strength, processability, and transparency comparable to petroleum-based polymers. However, its low elasticity and high rigidity at room temperature, as well as poor moisture and gas barrier properties limit its applicability. On the other hand, this biopolymer has a significant potential for optimizing physical properties through material modifications, including in combination with natural additives. This review will provide a comprehensive update on PLA modification methods to improve its film properties, with special emphasis on the use of plasticizers and compatibilizers, and the incorporation of antioxidants, antimicrobials and other bioactive compounds. In addition, applications of PLA polymers incorporated with natural additives for active food packaging will be discussed, along with their characterization and antimicrobial activity.