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Starch and chitosan are biodegradable polymers from renewable sources that can be used to overcome the serious environmental problem caused by improper disposal of synthetic plastic materials, non-biodegradable, derived from petroleum sources. The starch-chitosan based films manufactured allow improving the better characteristics of each one, adding their good characteristics and compensating for some limitations. In this work, it was studied: two sources of starch (corn and cassava), two different modes of chitosan addition (chitosan blended in the starch filmogenic solution and chitosan as coating), and the effect of glutaraldehyde as crosslinking agent. All films were prepared by casting using glycerol as a plasticizer and were characterized by their physicochemical (water vapor permeability, water contact angle, and FTIR), mechanical, and antimicrobial properties. The properties analyzed were influenced by all variables tested. Moreover, the principal component analysis was also conducted in order to relate and describe the variables analyzed. The antimicrobial activity of the corn starch-based films containing chitosan was confirmed, and these films have potential for development of active packaging.

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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 ΔE* 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.