บทคัดย่องานวิจัย

หมวดหมู่ : ฐานข้อมูลงานวิจัย

Comparison of leaf susceptibility to enzymatic blackening in Protea neriifolia R. Br. and Leucospermum 'Rachel'.

Dai JingWei; Paull, R. E.;

Postharvest Biology and Technology Year: 1997 Vol: 11 Issue: 2 Pages: 101-106 Ref: 21 ref.

1997

บทคัดย่อ

Comparison of leaf susceptibility to enzymatic blackening in Protea neriifolia R. Br. and Leucospermum 'Rachel'.

Leaf susceptibility to blackening differs between cut flowers of Protea neriifolia and Leucospermum cv. Rachel ((L. lineare x L. vestitum) x L. glabrum); members from different genera of the family Proteaceae. Leaf discs from mature green leaves of P. neriifolia (cv. Pink Mink) had a greater dry weight percentage and a higher protein and total phenolic content than Leucospermum leaf discs. No significant difference was observed in ascorbic acid content in fresh leaf tissues of the 2 genera. Polyphenol oxidase (PPO) [catechol oxidase] activity was high in P. neriifolia leaf homogenates with none being detected in Leucospermum leaf tissue at any pH. A significantly higher pH was observed in P. neriifolia leaf homogenates (pH 5.2) than in Leucospermum leaf homogenate (pH 4.4), with pH 5.2 being the optimum pH for PPO activity in P. neriifolia leaf. Mixing P. neriifolia leaf extract with Leucospermum leaf extract at pH 4.4-6.8 inhibited PPO activity, suggesting that Leucospermum leaf extract contain

ed an unknown PPO inhibitor. It is suggested that the absence of leaf blackening in Leucospermum could be due to either or both the lower leaf homogenate pH and the presence of an inhibitor.