Development of active/intelligent food packaging film containing Amaranthus leaf extract for shelf life extension of chicken/fish during chilled storage

Composite active/intelligent food packaging film was developed with polyvinyl alcohol (PVA) and gelatin incorporated with Amaranthus leaf extract (ALE) to monitor freshness of fish and chicken meat. ALE was rich in phenolic compounds, betalains and showed excellent antioxidant activity. ALE changed colour under basic pH due to the betalains present in it. The effect of ALE addition on the physical, mechanical and functional properties of the film was evaluated. Film containing ALE showed increased protection against UV light, reduced water solubility and water vapour permeability and had better mechanical properties. The inclusion of ALE, imparted antioxidant, antibacterial and intelligent properties to the film. When applied to preservation of chilled fish/chicken, the films were active as they delayed microbial growth and minimised oxidative rancidity. Samples packed in neat films had a shelf life of 3 days while those in active films spoiled after 12 days. The film also showed visible colour change from red to yellow on spoilage and this corroborated with the increase in pH, TVBN and microbial counts of the spoiled samples. Therefore, ALE incorporated PVA-gelatin films being both active and intelligent could be used for packaging of flesh foods.