Mechanical and antimicrobial properties of high amylose corn starch/konjac glucomannan composite film enhanced by cinnamaldehyde/β-cyclodextrin complex

Abstract

In the present research, cinnamaldehyde/β-cyclodextrin (CIN/β-CD) complex (0.5 %–3.0 %, w/v) were added into the composite film of high amylose corn starch (HAS) and konjac glucomannan (KGM) and the structural, physicochemical and bacteriostatic properties of the films were investigated. The results showed that the presence of CIN/β-CD complex decreased the crystallinity and short-range order structure of high amylose corn starch/konjac glucomannan (HAS/KGM) composite film. The CIN/β-CD complex also enhanced the polymeric interaction between the two polysaccharides, which improved the thermal ability of the composite film. The scanning electron microscopy (SEM) images showed compact and even surface and cross-section structure of the composite films when the complex addition was lower, while displayed heterogeneous aggregations of CIN/β-CD complex in the film with some pores after excessive addition of the complex. The mechanical strength of the film increased significantly from 14.51 MPa to 23.88 MPa and the water vapor resistance was improved due to the changes in skeleton structure of the composite film. The composite films exhibited obvious inhibition activity to Staphylococcus aureus and Escherichia coli, which displayed a promising application in food active packaging.