Development of intelligent food packaging from turmeric (Curcuma longa)

Abstract

In this study, intelligent food packaging in the forms of film and coating were developed based on starch, chitosan and curcumin extracted from turmeric. Solution casting method was applied to develop the film. Both of the film and coating were evaluated and compared by their chemical, physical and biological properties. The film was evaluated in terms of tensile strength measurement, FTIR spectroscopy, antioxidant activity and antimicrobial activity as well as color difference parameters after application on the strawberry. The results obtained showed that the film has a tensile strength of 1.37 MPa, elongation at break of 18.9%, antioxidant activity of 95.65% and high antimicrobial activity as the film had successfully delayed the formation of mould on the strawberry after 5 days of storage. In addition, the stability of both film and coating were evaluated based on their applications on strawberries at two different conditions which are at room temperature and chiller temperature during 5 days storage to identify their potential use as intelligent food packaging. After 5 days, it was found that the film at room temperature had been partially degraded and the coating had caused colour degradation and texture deterioration of the strawberry. In contrast, the film and coating stored at chiller temperature remained the same in terms of physical structure and able to monitor and extend the shelf life of the strawberry. For the evaluation of the film as pH sensing film, the colour of the film changed after 5 days from 53.46 to 48.92 for L*, 26.01 to 22.68 for a* and 42.49 to 44.65 for b* at chiller temperature, while at room temperature, the values of L* changed from 53.96 to 48.96, 25.54 to 20.36 for a* and 46.34 to 44.10 for b*. These showed that the film was able to monitor the freshness of the strawberry by changing its colour in respond to pH changes of the strawberry. The results obtained revealed that both of the film and coating have a greater stability at chiller temperature as compared to storage at room temperature and both have a strong antioxidant activity and strong antimicrobial activity that they delayed the spoilage of the strawberries. Therefore, the film and coating based on starch, chitosan and curcumin can be used to monitor freshness of refrigerated food and have the potential to be used as intelligent food packaging.