These studies develop edible

coatings using as biopolymer chitosan additive

with nanoZnO and evaluate the effectiveness in

preserving in guavas. To determinate the best

conditions were used the fractional factorial 24-1

experiment design technique. All assays was

conducted at 22 ± 1.0°C and samples were

taken at 48 hours to determinations of total

acidity (TA); soluble solids (SS); SS/TA ratio, pH,

water activity (aw) and weight loss. The results

demonstrate the coatings containing chitosan

pure (0.5%) and chitosan (0.5%) + nanoZnO

(0.2%) were effective against the onset of rot. A

new set of assays with chitosan coatings (0.5%)

and chitosan (0.5%) + nanoZnO (0.2%) was

conducted with 21 days of storage time. The

results compared with controls (fruits without

coating), showed higher levels SS and SS/TA

ratio, especially fruit coating containing nanoZnO

and inhibition of microorganism contamination.

Also demonstrated that nanoZnO prevent

the ripening of the fruit due the antimicrobial

activity of nanoZnO. This result suggests the

potentiality/viability in edible coatings chitosan

with nanoZnO.