Degradation Kinetic Modelling of Colour, Texture, Polyphenols and Antioxidant Capacity of York Cabbage after Microwave Processing

Vegetables as an essential component of the human diet usually undergo some type of processing before being consumed. In the present study, impact of microwave (MW) processing on various physiochemical properties of York cabbage was studied. York cabbage was processed at 400, 560 and 800W for 0 to 14 min with an increment of 2 min followed by a kinetic study for the degradation of polyphenols, flavonoids, antioxidant capacity, colour and texture were carried out. Results showed that MW processing leads to significant reductions in the texture, colour, polyphenols and antioxidant capacity. For all the MW processing power studied total phenolic content reduced by up to 85-90% while total flavonoid content reduced by up to 60-73% after 14 min of MW processing. These results were further confirmed by HPLC-DAD analysis. Serious losses in the antioxidant capacity (83-98%) were also observed as a result of MW processing as compared to fresh counterparts and a similar trend was observed for firmness, which reduced by up to 58.8-61.6%, and colour up to 15.2-36.9%. First-order reaction model showed a good fit for the different studied parameters, with coefficients of determination (R2) ranging from 0.90 to 0.99, except for texture (firmness) and colour (chroma), which followed zero-order (R2= 0.88-0.98)