Influence of Blueberry and Jaboticaba Agroindustrial Residue Particle Size on Color Change of Corn Starch Based Films Submitted to Different pH Values Solutions

Corn starch, glycerol and agroindustrial residues were used to produce films by casting. By-products from juice processing, blueberry and jaboticaba in powder with different particle sizes were added in the filmogenic matrix to evaluate its potential as a colorimetric indicator. Blueberry and jaboticaba peels are commonly discarded although contain high amount of important compounds as anthocyanins. These compounds have the ability to color change after immersion in different pH values, demonstrating its potential for the intelligent packaging development. Analyses were performed in a colorimeter after films immersion in different buffer solutions. Visual color changes were perceived; reddish and bluish color in acidic and basic pH values, respectively. Independently of the particle size, the Delta E* values were greater than 5, showing visually perceptible change to the human eye. The results indicate the potential of use of these residues as a pH indicator for the development of renewable and biodegradable sensor of food deterioration.