Effects of myrtle (Myrtus communis L.) fruit cold storage under modified atmosphere on liqueur quality.

ABSTRACT
Myrtle berries were stored for 30 days at 2C in air (control) or O2 at 60 or 80%
with the aim to extend the liqueur processing season. Oxygen treated berries had
a lower pH and titratable acidity than control. No treatment effect was observed
on weight loss and respiration rate. CIELAB coordinates demonstrated a darkening
of the oxygen treated fruit. Hydro-alcoholic extracts (HAE) from berries
stored for 30 days at 80% O2 were less red colored than other treatments. After 10
and 20 days of storage, fruit held at 80% O2 had significantly higher total phenols
than other treatments. Total anthocyanins increased with storage in all treatments.
In the first 20 days of storage high oxygen treated berries showed higher anthocyanin
content than control, whereas no difference among treatments were observed
at 30 days. No differences were observed for the anthocyanin content in the HAE.
PRATICAL APPLICATIONS
The extension of the myrtle liqueur processing season is a major need for liqueur
industries. In this article, the application, on myrtle berries, of postharvest storage
in association with high oxygen treatments, proved to be useful to delay the processing
time and, at the same time, to provide the liqueur industries of myrtle berries
with good quality traits. The most important quality attributes for myrtle
berries destined to transformation are the phenolic compounds in particular
anthocyanins. Oxygen treatments have been successfully used for other commodities
to improve the quality traits related to phenolic content. The results of this
study will benefit the transformation industries in order to delay the processing
season and to standardize the liqueur production. Furthermore it will add new
data on the postharvest performances of small fruits.