English abstract
Abstract: But ( ¯ Sideroxylon mascatense) is an indigenous wild blueberry found in Oman. It has a very
short season and is commonly preserved by drying. The aims of this study were to determine the
physico-chemical characteristics and stability of phytochemicals (i.e., polyphenols and flavonoids)
in the berries during drying (i.e., freeze-drying at −40 ◦C and air-drying at 60 and 90 ◦C) and the
polyphenol stability of the dried berries as a function of storage temperature (i.e., 90, 70, 60, 40, 20,
and −20 ◦C). The moisture content of fresh berry flesh was 64.5 g/100 g sample (wet basis). The
crude protein and fat contents were higher in the seeds than in the flesh. Glucose and fructose were
the main sugars and their concentrations were highest in the sample air-dried at 60 ◦C. The initial
total polyphenol content (TPC) and total flavonoid content (TFC) of the flesh were 2.009 mg gallic
acid equivalent (GAE)/g dry-solids and 0.199 mg catechin equivalent (CE)/g dry-solids, respectively.
The samples air-dried at 90 ◦C and freeze-dried at −40 ◦C had higher TPC (i.e., 2.638 mg GAE/g
dry-solids) and TFC (i.e., 0.395 mg CE/g dry-solids), respectively. There was a significant difference
between the TPC and TFC of fresh and dried wild berries (p < 0.05). The freeze-dried wild berries
retained a high TPC compared to the air-dried samples. The polyphenol storage stability of freeze dried wild berries at different storage temperatures showed two phases: an initial release phase
followed by a decay phase. The polyphenol storage stability was modeled using the Peleg model and
the kinetic parameters were correlated with the storage temperature.
