Nanostructured pH-Indicator Films Based on Cassava Starch, Laponite, and Jambolan (Syzygium cumini) Fruit Manufactured by Thermo-Compression

摘要

This work aims to develop pH-indicator films based on cassava starch and anthocyanins from jambolan (Syzygium cumini) fruit by thermo-compression, as well as to study the effect of laponite (Lap) on the physicochemical properties of the thermo-pressed films. Films manufactured with Lap and jambolan fruit are more colorful than those produced without Lap, indicating that Lap can be used to preserve the purple color in the films during the thermo-compression or during the exposition to the visible light irradiation. Physicochemical results such as chemical structure, crystallinity, thermal transitions, morphology, thickness, and density suggest that the molecular spacing in the amylose/amylopectin chains is altered with the presence of Lap and jambolan fruit. Finally, films containing Lap and jambolan fruit show visible changes from purple color to yellow color when used to monitor the freshness of round steak stored at -20, 4, and 20 degrees C. Based on colorimetric and physicochemical results, films based on cassava starch, Lap, and jambolan fruit can be manufactured by thermo-compression and they can be used to monitor the meat freshness.