Quality evaluation of strawberries coated with water-in-oil based emulsion using an advanced electrostatic spray coating system

In this study, the impact of formulated emulsion was studied on strawberries which were coated using dip and electrostatic spray coating methods. The coated strawberries were kept at room temperature for a period of 12 days. A significant level of chargeability of w/o emulsion was achieved in terms of charge-to-mass ratio of 2.81 mC/kg at an applied high voltage of 2.0 kV, applied air pressure of 0.3 MPa, and liquid flow rate of 33.6 ml/min. The distance of 170 mm from the nozzle tip to Faraday cage was maintained during the measurements. As compared to uncoated and dip coated strawberries, the water-in-oil based electrostatically charged sprays considerably (p < 0.05) reduced the weight loss, decay rate, pH, titrable acidity, TSS, and antioxidant activity. In both the cases, i.e. strawberries coated with dip and electrostatic spray coating methods, the same weight loss was observed, however, there was a considerably less weight loss as compared to uncoated samples. The textures of the uncoated (9.02 N) and dip coated (12.58 N) samples were significantly different from the electrostatic spray coated (15.85 N) samples. Since, the coating formulation had no impact on the sensory attributes, the samples were considered as acceptable at the end of the storage. Furthermore, compared to uncoated, water-in-oil based electrostatically charged spray coating was more effective at delaying the decay by 12 days.