Preferential binding effect of cocoa powder on fried donuts through the electrostatic coating method

Abstract

Donuts are the snack food which are coated with powdered seasonings to increase flavour and shelf life. In this regard, electrostatic coating is being developed for efficient coating method and to overcome uneven coating and dust production. During electrostatic coating, charged powder particles produce even coating on target surface. Electrostatic coating of cocoa powder was carried out at high voltage (0-20 kV) and the results were compared to manually coated fried donuts. Cocoa powder particles had irregular polygonal and polyhedral shapes with an average particle diameter (18.12 AE 0.91 μm). The values of adhesion, dust reduction and transfer efficiency were higher at 15 kV and lower values at 0 kV. Coated sample at 15 kV showed the lowest change in weight loss (05.99%) during the storage. Due to an even coating of cocoa powder at 15 kV, donuts exhibited pleasant taste, uniform and dark brown colour. While, shelf life of coated donuts at 15 kV lasts up to 29 days as compared to other samples. It can be concluded from the results that the electrostatic coating of donuts with cocoa powder was best at 15 kV with higher transfer efficiency, adhesion and consumer acceptability.