The biological characteristics of plantain during after-ripening and its relationship with maturity

To find the determining indicator of plantain maturity，the changes of some biological indicators of plantain during after-ripening and its correlation with surface color were studied. The plantain was stored at 15℃ and relative humidity of 85% for ripening naturally. During the 12 days of after-ripening，the polyphenol oxidase（ PPO） activity and peroxidase（ POD） activity，titratable acid content，pH value，ascorbic acid and insoluble dietary fiber content were determined，and their correlation with surface color was analyzed. Results showed that during afterripening， the PPO activity and POD activity increased，the titratable acid and insoluble dietary fiber content increased gradually. On the whole，the content of ascorbic acid decreased with fluctuation. The pH value and the h value of surface color decreased obviously. Using SPSS software analysis，the insoluble dietary fiber content was significant with h value of surface color. The correlation of PPO，POD activity，titratable acid and pH value with the h value was extremely significant. The R value of the titratable acid content and pH value was higher among them. Therefore， the measured indicators can reflect the maturity of plantain well. And combined with the convenience of operation，pH value can be used as a judgment indicator of maturity during after-ripening，also as the theory foundation for the determination of plantain fruit maturity，even in the process.