Relationship between α-farnesene, conjugated-trienes and superficial scald development on stored ‘Granny Smith’ apples

Superficial scald is a physiological disorder that can appear after cold storage on apples and pears.
It has been largely assumed that the oxidation products of α-farnesene during storage may be the causal agent of scald.
These products are called conjugated-trienols (CTols). The aim of this work was to know the critical moment when the accumulation of CTols may cause scald development on ‘Granny Smith’ apple.
In order to get different scald susceptibility, apples were harvested at two different dates and stored in air or in different controlled atmosphere conditions (CA, LO, and ULO). Scald development, α-farnesene and CTols were measured at harvest and after 2, 4 or 6 months of storage with additional shelf-life periods (1, 4 and 10 days at 20°C). Hexane extracts were used to estimate α-farnesene and CT₂₈₁ (CTols measured at 281 nm) values, which were correlated with scald index.
The level of α-farnesene was affected by storage conditions but was not related to harvest date, while on CT₂₈₁ the effect of harvest date was greater than the storage conditions.
Correlations obtained between CT₂₈₁ values in fruit stored for 2 months and scald index after 4 or 6 months storage were stronger than correlations obtained at the same time of scald assessment.
It seems that the oxidation of α-farnesene at the initial period of cold storage is the key to scald development at the end of long storage.

VIII International Postharvest Symposium: Enhancing Supply Chain and Consumer Benefits – Ethical and Technological Issues

Y. Soria, I. Recasens

Malus domestica, physiological disorder, cold storage, controlled atmosphere

https://doi.org/10.17660/ActaHortic.2018.1194.66