Polyphenol Oxidase and Peroxidase Expression in Four Pineapple Varieties (Ananas comosus L.) after a Chilling Injury

• Published in: Journal of agricultural and food chemistry 2011-01, Vol.59 (1), p.342-348
• Main Authors: Raimbault, Astrid-Kim, Marie-Alphonsine, Paul-Alex, Horry, Jean-Pierre, Francois-Haugrin, Madlyn, Romuald, Karell, Soler, Alain
• Format: Article
• Language: English
• Subjects: Ananas - enzymology; Ananas - genetics; Biological and medical sciences; Catechol Oxidase - genetics; Catechol Oxidase - metabolism; Cold Temperature; Food Chemistry/Biochemistry; Food industries; Fruit - enzymology; Fruit - genetics; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Enzymologic; Peroxidase - genetics; Peroxidase - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf102511z

Pineapple internal browning (IB) is a chilling injury that produces enzymatic browning associated with flesh translucency. Pineapple biodiversity allowed the investigation of how polyphenol oxidase (PPO) and peroxidase (POD) activities with their different isoforms are involved in the IB mechanism. Fruits of four varieties that expressed IB symptoms differently, Smooth Cayenne (SCay) and the hybrids MD2, Flhoran 41 (Flh 41), and Flhoran 53 (Flh 53), were stressed by cold. The susceptible varieties showed classical brown spots but different patterns of IB, whereas MD2 and controls showed no IB. Enzymatic activities were measured on fruit protein extracts and PPO and POD isoforms separated on mini-gels (PhastSystem). Only PPO activity was significantly enhanced in the presence of IB. Up to six PPO isoforms were identified in the susceptible varieties. PPO was barely detectable in the nonsusceptible variety MD2 and in controls. The number of PPO isoforms and the total PPO activity after chilling are varietal characteristics.