Application of different ways of fruit juice pasteurization might impact differently the quality of the products. As thermal processing can drastically diminish the quality of the product, alternative non-thermal means of pasteurization are being tested. One of them is cold plasma, which has no negative consequences on product nutritional and sensory quality. Cold plasma treatment used in a short period of time (5 s) does not diminish the content of vitamin C, although with an increase of the processing time (20 s) quality deterioration might take place. The stability of anthocyanins after the application of cold plasma depends on the type of fruit juice. The content of anthocyanins in pomegranate juice remains stable, while their content in blueberry juice diminishes considerably. The content of polyphenols and flavonoids can increase with the use of cold plasma, but might decompose if the exposure time is too long. The colour of fruit juices does not change after the application of cold plasma as it happens with thermal processing, where unwanted brown pigments form. Microorganisms can be completely inactivated with cold plasma but we also have to consider the quality of the product and empirically set optimal parameters. Pressure, tension, processing time and gas type are the parameters that must be taken into consideration and adjusted according to the type of juice and required results.
|
