The addition of polyphenol-rich extracts to chitosan-based films, such as green tea extracts [ 121 ], apple extracts [ 69 ], banana peel extract [ 67 ], Chinese chives [ 122 ], root extract [ 123 ], mango kernel extract (honeysuckle flower extract [ 124 ], Pistacia terebinthus leaf extract [ 125 ], syringic acid, and purple pulp sweet potato extract [ 126 ], protocatechuic acid [ 127 ], resulted in an overall trend of decreasing TS and % E values. 2.4.
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