Shelf-life of fresh blueberries coated with quinoa protein/chitosan/sunflower oil edible film

Abstract

The aim of this study was to evaluate quinoa protein (Q), chitosan (CH) and sunflower oil (SO) as edible film material as well as the influence of this coating in extending the shelf-life of fresh blueberries stored at 4 ∘C and 75% relative humidity. These conditions were used to simulate the storage conditions in supermarkets and represent adverse conditions for testing the effects of the coating. The mechanical, barrier, and structural properties of the filmwere measured. The effectiveness of the coating in fresh blueberries (CB) was evaluated by changes in weight loss, firmness, color, molds and yeast count, pH, titratable acidity, and soluble solids content. RESULTS: The tensile strength and elongation at break of the edible film were 0.45±0.29 MPa and 117.2%±7%, respectively. Thewater vapor permeabilitywas 3.3×10−12 ±4.0×10−13 gs−1 m−1 Pa−1. In all of the color parameters CB presented significant differences. CB had slight delayed fruit ripening as evidenced by higher titratable acidity (0.3–0.5 g citric acid 100 g−1) and lower pH (3.4–3.6) than control during storage; however, it showed reduced firmness (up to 38%). CONCLUSION: The use ofQ/CH/SO as a coating in fresh blueberrieswas able to control the growth ofmolds and yeasts during 32 days of storage, whereas the control showed an increasing ofmolds and yeast, between 1.8 and 3.1 log cycles (between 20 and 35 days).