BROWNING IN 'BRAEBURN': A METABOLOMICS APPROACH FOR BIOMARKER IDENTIFICATION

Apples are stored under controlled atmosphere conditions to ensure out-of-season market availability to consumers. However, the susceptibility of ‘Braeburn’ (Malus × domestica Borkh.) apples to internal browning is responsible for large economic losses. The objective of this study is to understand the biochemical processes involved in the development of browning in storage using a metabolomic approach, as part of a larger study to identify a biomarker for disorder development. ‘Braeburn’ apples were harvested and sampled at harvest, and up to 8 months of storage under browning-inducing conditions. Metabolite profiles were analysed using GC/MS. The results show that ‘Braeburn’ developed browning early in storage, the severity increased with storage duration, and this could be attributed to a group of metabolites that showed either an increase (alanine, galactose, mannitol, sorbitol, xylose) or a decrease (malic acid, sucrose) in concentration between the different time points. A distinction between the inner and outer cortex samples was also observed; the inner samples were closely linked to browning.