Abstract
Polysaccharide-lipid edible composite coatings can extend fruit shelf-life by providing a barrier to gas and water vapor exchange between the fruit and its environment, reducing respiration rate and weight loss. Among other factors, coating barrier properties depend on coating composition and thickness, which depends on the solid content of the formulations. The objective of this work was to study the effect of hydroxypropyl methylcellulose (HPMC):beeswax (BW) ratio and solid content (SC) of HPMC:BW composite coatings on the quality of 'Clemenules' mandarins. HPMC of two different molecular weights were used to prepare emulsion coatings at three HPMC:BW ratios (1:1, 1:3, 1:30), with 4% and 8% SC and similar viscosity. After coating, mandarins were stored up to four weeks at 4C (39.2F) followed by one week at 20C (68F). Fruit quality analysis was done periodically during storage. Coatings reduced weigh loss and improved texture of mandarins compared to uncoated samples. Weight loss and texture were not affected by SC. However, as SC increased, internal CO2, ethanol and off flavor increased and fruit appearance worsened. Increasing the BW content reduced weight loss, CO2, ethanol levels and off flavor. However, coatings with 1:30 HPMC:BW ratio presented a whitish appearance.
