Effect of tara gum and nano-CaCO3 edible coatings on postharvest quality and shelf-life extension of guava (Psidium guajava L.)

The use of biodegradable and edible coatings has become an alternative for the preservation of postharvest fruits, replacing traditional plastic. In this work, an active coat based on tara gum, supplemented with nano-CaCO 3 , was developed. The synthesis of nano-CaCO 3 was optimized using design of experiments, reaching the best condition with a flow rate of 0.25 mL·min −1 , a 1:5 ratio of reagents, and a temperature of 17.5 °C, resulting in a hydrodynamic radius of 64.80 ± 7.77 nm. Thus, 0.1%, 0.3%, and 0.5% (w/v) of nano-CaCO 3 were dispersed in the tara gum 1.5% (w/v). All coating conditions were applied to guava fruits. The coated fruits had a decrease in weight loss and firmness with less variation in the fruit peel color. The pH, titratable acidity, soluble solids, and reducing sugars were kept similar, indicating that the coating does not change the physicochemical properties of the guavas. The results show that it is possible to develop a nanotechnological packaging that preserves postharvest guavas, increasing the shelf life of the fruit up to 137.5%.