부산대학교 도서관

This work evaluates the extraction of anthocyanins from star apple (Chrysophyllum cainito L.) fruit peel as an indicator in smart films that respond to color change at different pH concentrations of 1, 3, 5, 7, and 9. Thermoplastic films (TPS) composed of corn starch and concentrations of 10%, 20%, 30%, 40%, and 50% (w/w) of Chrysophyllum cainito L. peel extract were fabricated for characterization. The FTIR results revealed the characteristic bands of the polymer composed with extract and evidenced the increase of this compound exhibiting an increase in the intensity of the bands. SEM results evidenced the interaction between starch and glycerol, as well as an increase in the growth of clumps as the anthocyanin concentration increased; similar tendency was observed in the thermal analysis. The degradation temperatures and mass loss varied as the amount of anthocyanin contained in the film increased. The evaluation of the response of the films as indicators against various pH’s showed saturated color changes as the % anthocyanin contained in the film increased at all pH values evaluated. According to the obtained results, it is concluded that the anthocyanin concentration influences the physicochemical and thermal properties of the films; therefore, TPS/anthocyanin films are potential candidates to be used as pH indicators in the food industry.