Enhancement of oil spreadability of biscuit surface by nonthermal barrier discharge plasma

• Nonthermal dielectric barrier discharge (DBD) plasma treatment of biscuits was carried out.
• The plasma source was electrically and optically characterised.
• An image analysis approach was employed to quantify spreading of oil on biscuit surface.
• Both treatment time and a voltage of 80 kV significantly enhanced spreading of oil.
• The novel process is amenable to continuous industrial scale processing.

The application of nonthermal dielectric barrier discharge (DBD) plasma for altering the hydrophilicity or hydrophobicity of polymer surfaces is well known. In this work, we demonstrate the potential of DBD plasma in enhancing the surface hydrophobicity of freshly baked biscuits, evident from the increased spread area of vegetable oil. The electrical and optical characteristics of the DBD plasma source have also been described. The spread area of individual oil drops has been measured using a digital image analysis technique. An exponential order of increase in the spread area has been observed at 80 kV with respect to treatment time, following DBD treatment. The findings reported in this work have applications in the industrial preparation of biscuit and cracker variants, where post-baking oil spray is desired. The effect of plasma treatments on the chemical constituents of biscuit requires further investigation.Industrial relevanceThere is a substantive evidence for the need of an alternate process which allows retaining functionality of sprayed oil in biscuits, with less oil or fat and increased spread. A novel process based on barrier discharge atmospheric pressure nonthermal plasma for enhancement of oil spreadability on dry, snack food products is developed. For a given volume of oil, up to 50% more spreading of oil can be achieved within few seconds of the process as compared to currently used methods. The plasma source can be easily integrated into a continuous biscuit and cracker production or finishing line.