Study on enhanced mechanical, barrier and optical properties of chemically modified mango kernel starch films

摘要

The main aim of this study was to chemically modify mango kernel starch (MKS) and assess its impact on packaging film properties. MKS exhibited limited application due to low solubility, retrogradation, higher gelatinization temperature and hydrophilicity. These limitations could be effectually overcome by integrating modifications to native starch. Chemical modifications of MKS were performed by oxidation and benzylation with a low degree of substitution. X-ray diffractogram presented A-type pattern of crystal structure which was in accordance to endosperm starch. Fourier-transform infrared (FTIR) spectra of the native and modified starch samples exhibited strong bands in the regions corresponding to OH and CH stretching. Additionally, absorption bands were found in the regions for carbonyl and aromatic phenyl vibrations signifying the substitution of functional groups within native starch. Modified starch films presented increased lightness L* representing that the films were lighter in colour than native film. Tensile strength (TS) of modified films was found to increase more than twice that of native starch film. Starch recrystallization was interrupted by oxidation thereby preventing retrogradation. Benzylation lowered the water vapour permeability by 58% and improved UV absorption by 80% when compared with native film.