Development of pH indicator and antimicrobial cellulose nanofiber packaging film based on purple sweet potato anthocyanin and oregano essential oil

International Journal of Biological Macromolecules 2020

Development of pH indicator and antimicrobial cellulose nanofiber packaging film based on purple sweet potato anthocyanin and oregano essential oil

Shunli Chen, Min Wu*, Peng Lu, Lin Gao, Shun Yan, Shuangfei Wang

摘要：A pH indicator and antimicrobial cellulose nanofibre packaging film was developed based on cellulose nanofibres as film matrix, anthocyanins from purple sweet potato as a natural dye and oregano essential oil as an antimicrobial agent. The colour of the anthocyanin solution was noticeably different from pH 2 to pH 12. The developed film sensitively responded to a change of pH and showed an obvious colour change from red to yellow, with pH ranging from 2 to 12, which indicated that the film had a superior colorimetric performance to pH change. Moreover, the film showed excellent antimicrobial activity and the inhibition rate against Escherichia coli and Listeria monocytogenes reached 99.99%. Bio-compatibility between anthocyanins and cellulose nanofibre matrix was confirmed by the analysis of cross-section morphology of the film. The XRD pattern revealed that the crystallinity index of the film decreased with the addition of anthocyanins and oregano essential oil. The film had a good barrier performance to ultraviolet and visible light; its tensile strength, elongation at break, and elastic modulus was 9.28 MPa, 9.87%, and 0.15 GPa, respectively. The developed pH indicator and antimicrobial film could intuitively indicate the change of food quality during storage and effectively prolong food shelf life.

DOI：https://doi.org/10.1016/j.ijbiomac.2020.01.231