TiO2 incorporated into a blend of biopolymeric matrices improves film properties and affects the postharvest conservation of papaya fruits under UV light

This work investigated the properties of chitosan-cassava starch biopolymeric films containing nanometric photoactive TiO2 particles for use in postharvest conservation of papaya fruits under UV light at a temperature of 15 +/- 1 degrees C and a relative humidity of 90 +/- 1 % for 24 days. Starch-chitosan blend films showed intermediate hydrophobicity and improved mechanical properties. The addition of 1 % TiO2 into the polymeric matrix of starch/chitosan (1:1) further improved the mechanical properties with solubility of 16.04 +/- 0.41 %, visible transmittance of 31.76 +/- 1.58 %, and reduced UV transmittance of more than 97 %. However, the addition of TiO2 exceeding 1 % led to the formation of agglomerates and excessive reduction in film transparency. UV exposure damaged the fruit peel and resulted in a higher weight loss. In contrast, the addition of 1 % TiO2 to the blend reduced the weight loss in light and dark by 7.12 +/- 1.57 % and 5.27 +/- 0.31 % respectively, and delayed fruit ripening.