Spraying process study of A chitosan formulation containing gallic acid for The preservation of fruits

Abstract

The spraying of a formulation containing gallic acid (GA) and chitosan (CS) is investigated to generate GA-CS coatings over fruit surfaces and thus extend their shelf life. The performance of three sprayers is assessed exploring the atomizing distance and the formulation concentration used. The characterization of droplet size distribution and the GA-CS formulation concentration deposited on the sample surface is performed by image analysis; the antioxidant activity, maturity index, the mass evolution and acidity for fruit ripening were also assessed. A more uniform size distribution of GA-CS coating over substrate surface was obtained as an atomizer nozzle of 0.70 mm sprayed a 0.80 formulation dilution at 20 cm. This coating helps to preserve the fruit quality, exhibiting a half maximum inhibitory concentration (IC50) and a mass loss lower than unsprayed samples. Coated tomatoes and tangerines show a remarkable improvement in antioxidant activity regarding pristine samples. Indeed, sprayed tangerines exhibit a clear time extension in antioxidant activity of at least 5 days. Despite the GA-CS coating of fruit surfaces has a discontinuous droplet-type morphology, it turns out to be an active, inexpensive and efficient tool capable of extending the fruit's shelf life.