Comparison of phenolic composition of healthy apple tissues and tissues affected by bitter pit.

Bitter pit is an important Ca(2+) deficiency disorder of apple fruit (Malus domestica Borkh.), with symptoms, necrotic spots, developing during storage. The objective of this study was to determine phenolic compounds and their contents in bitter pit in comparison to healthy skin and pulp using HPLC-MS(2). The experiment was carried out on three cultivars 'Jonagored', 'Golden Delicious' and 'Pinova'. All 15 determined phenolic compounds in pulp tissues specifically affected by bitter pit were higher than those in healthy pulp. Chlorogenic acid and catechin were to 5 times higher in those affected pulp tissues. Higher content was also determined for hydroxycinnamic acids and flavanols in the peel above the bitter pit; in contrast, flavonols and anthocyanins were higher in healthy peel. Anthocyanins in healthy peel of cultivar 'Jonagored' were 10 times higher from the content in peel above the bitter pit.