Biochemical characterisation of core browning and brown heart disorders in pear by multivariate analysis

Multivariate analysis was used to characterise and differentiate two important postharvest disorders that occurred in pear (Pyrus communis L.) during storage: brown heart (BH) and core browning (CB). Incidence of each kind of disorder was correlated with the length of storage. storage CO2 concentration and activity of enzymes involved in fermentative and oxidative metabolism. The first characterisation of samples by principal component analysis (PCA) clearly distinguished healthy and damaged fruit. Within the damaged group, the model also discriminated between fruit with BH and those with CB. CB appeared first, followed by BH. A partial least-square (PLS) regression model that quantified the importance of each variable in predicting the disorder percentage was then established. According to this model, CB mainly correlated with the fermentative enzyme alcohol dehydrogenase (ADH), whereas BH correlated with the antioxidant enzymes ascorbate peroxidase (APX) and catalase (CAT). Collectively, these results suggest that core browning and brown heart involve different metabolic pathways. (C) 2003 Elsevier B.V. All rights reserved.