Effect of Antimicrobial Edible Coatings on Quality and Shelf Life of Minimal Processed Guava (Psidium guajava)

The present study aimed to develop an antimicrobial edible coating and to evaluate their efficiencies in preservingguava slices. Guava slices were submitted to four treatments: without coating (control) A, coating with potato starch containing 0.25% or 0.5% chitosan, B and C treatments respectively, and coating with 3% potato starch, 1.5% ascorbic acid and 0.2% potassium sorbate, D treatment. All samples were stored in refrigerator at 4±1°C and 70-75% relative humidity for 18 days. The following characteristics were analyzed: weight loss, firmness, total soluble solids, total titratable acidity, vitamin C, polyphenol oxidase (PPO), catalase (CAT), microbial quality and sensory attributes. Treatments with edible coatings were effective in reducing weight loss and maintaining texture of guava slices. The coatings decreased the increase in total soluble solids and decreased the loss in total titratable acidity compared to the uncoated ones. The lowest activity values of enzymes (PPO and CAT) were recorded for coated samples. The use of edible coatings contributed in reducing microbial growth of guava slices and increasing their shelf-life.