Preparation and characterization of active and intelligent PVA/Starch films using propolis extract and anthocyanin for food packaging applications

Abstract

Active and intelligent food packaging films have taken more importance over conventional packaging. The aim of this study was to develop active and intelligent food packaging films based on bio-degradable polymers (PVA and starch) incorporated with natural additives i.e. Propolis extract (PE) and Anthocyanin (ATH). Boric Acid (BA) and Glutaraldehyde (GA) were used as cross-linkers. These films are capable to resist against external bacterial attack by their anti-bacterial activity and color changing property due to change in pH. The results proved the compatibility of films mixture using two cross-linkers separately i.e. BA and GA. The mechanical strength was also measured and highest values were achieved 6.1 MPa and 15.9 MPa for PSB5A20PE and PSGA5A20PE, respectively. Moreover, the maximum zone of inhabitation i.e. 21 mm and 15mm was also achieved against E. Coli and MRSA, respectively for PSB5A20PE. However, the maximum zone of inhibition of 25 mm and 20 mm against E. Coli and MRSA was achieved for PSGA5A20PE, respectively. Furthermore, all films had shown great color response against different pH ranging from 1 to 14. Physical tests i.e. water vapor transmission rate, moisture retention capability, swelling degree and biological leaching tests were also performed to evaluate the physical compatibility of these films with food. Finally, food spoilage test was performed using pasteurized milk to validate the applicability of these films’ formulations. Films responded visibly by changing color and protected milk from spoilage through anti-bacterial property. All results have shown that PSB5A20PE and PSGA5A20PE film formulations have performed best against all evaluation techniques. Hence, these bio-degradable active and intelligent films have potential to be used in food packaging applications.