ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Cellular localisation of polyphenol oxidase and peroxidase activity in Litchi chinensis Sonn. pericarp.

Underhill, S. J. R.; Critchley, C.;

Australian Journal of Plant Physiology Year: 1995 Vol: 22 Issue: 4 Pages: 627-632 Ref: 25 ref.

1995

บทคัดย่อ

Cellular localization of visual browning and oxidative activity studies were conducted on Litchi chinensis fruits (cultivars Tai So and Kwai May Pink) to determine the relative significance of polyphenol oxidase [catechol oxidase] (PPO) and peroxidase (POD) activities during pericarp browning. Pericarp browning was first observed on the protuberance apices and subsequently extended uniformly over the entire pericarp surface. Anatomically, browning was highly localized and restricted to the epicarp and the upper mesocarp. PPO and POD activities were highest in the epicarp, with progressively less activity in both the mesocarp and endocarp. In situ localization of oxidative activity using tissue blots confirmed high epicarp PPO activity. POD activity, although primarily restricted to mesocarp vascular tissue, was also detected in the epicarp. It is proposed that litchi pericarp browning is due to highly localized oxidative activity in the epicarp and upper mesocarp. As PPO and POD activities were

significantly higher in this tissue and browning was not observed when both enzymes were selectively inhibited, it is postulated that both PPO and POD activities are associated with litchi pericarp browning.