Effects of anthocyanin-rich Kadsura coccinea extract on the physical, antioxidant, and pH-sensitive properties of biodegradable film.

The pH-sensitive films were developed by adding Kadsura coccinea (KC) extract to chitosan (CH), gelatin (GL), and sodium alginate (SA) matrix. Due to abundant anthocyanin content, KC could change its colors with changing pH value. The KC extract could significantly increase the thickness, water vapor barrier property (WVP), mechanical property, UV–vis light barrier property, mechanical properties, and antioxidant capacity of the films. However, the KC extract could considerably reduce moisture content and thermal behavior of the films. The CH-KC film had best oxidation resistance. The GL-KC film had best ultraviolet light transmission and thermal properties. The SA-KC film had best WVP and mechanical properties. Fourier transform infrared spectroscopy revealed the molecular interaction between polymer matrix and KC extract. Moreover, CH-KC, GL-KC, and SA-KC films were intelligent and showed significant color changes in different buffer solutions, but the effect of the GL-KC film was most obvious. The GL-KC films can be used as food active and intelligent packaging, especially for monitoring the freshness of meat and seafood with pH changes at room temperature. [ABSTRACT FROM AUTHOR]