Biochemical Changes Associated with Chilling in Pineapple Fruit
J.M. Dahler, S.J. Underhill, Y. Zhou and J.E. Giles
ISHS Acta Horticulturae 575: 603-610.
2002
บทคัดย่อ
Pineapple (Ananas comosus [L.] Merr.) fruit of variable cultuvar (‘Smooth Cayenne’ and PRI hybrid ‘73-50’) and maturity were stored at chilling temperatures to investigate the mechanism for blackheart inducement and development. When chilled for three weeks at 13 0C followed by7 days storage at 25 0C, fruit of both cultivars developed significantly increased polyphenol oxidase (PPO) activities concurrently with blackheart symptoms. Fruit stored continuously at 25 0C developed no blackheart. There was no corelation between peroxidase activity (POD)and blackheart development for either cultivar. The influence of fruit maturity on blackheart development was also investigated, by storing ‘Smooth Cayenne’ fruit of six maturity ranges for 3 weeks at 10 0C, or for 3 weeks at 10 0C followed by 7 days at 25 0C. Immature fruit developed negligible blackheart, while fruit of mid-range maturity were susceptible, the latter also developed increased PPO activity after 4 weeks. Over mature fruit developed a translucent breakdown of the pulp, rather than blackheart. Differences in subsequent fruit susceptibility to blackheart were not consistent wiith PPO activities at harvest. Total phenol concentration increased with fruit maturity, but high phenol concentration was not consistent with increased blackheart incidence. There was no significant difference in ascorbic acid levels at harvest between the maturity ranges. The suggestion in the literature that ascorbic acid level at harvest indicates susceptibility to blackheart is not support by our data.