Study on Discoloration Dynamic Characteristics of Apple Slices after High Pressure Treatment

摘要

The color-changing dynamic characteristics and polyphenol oxidase (PPO) of fresh-cut apple slices were studied with Fuji apple after different levels of high pressure treatment (0, 200, 300, 400 and 500MPa). Four kinds of indices, including delta LaA,delta Lab, A(AE) and delta N.I., were investigated to evaluate the color-changing. It was shown that each index had a linear correlation with the time exposed to atmosphere, no matter the treatments. This suggested that the color-changing of fresh-cut apple slices always conforms to zero-order kinetic reaction under experimental conditions. Experimental results also showed that PPO activity of apple slices decreased with increasing pressure. Due to a positive correlation between the color-changing rateand the PPO activity, ALafo was selected to be the best index to describe the effect of pressure-treated on color-changing rate, based Pearson correlation analysis. Basing on ALaA), a model with high correlation coefficient was established to present the relation between the color-changing rate and pressure. This mode was useful for adding color evaluation into whole quality evaluation of fresh-cut apple slices after high pressure processing.