Background and objective: Drying of date helps in preserving it to be consumed outside the harvest season and removes some moisture from dates and also slows down the action of date endogenous enzymes. This study was carried out to investigate pretreatments and drying temperature on the physical and chemical properties of 2 date varieties (Siwi and Sakkoti) at the khalal stage.
Materials and methods: The date fruits at khalal stage were dipped in ascorbic acid solution, sodium metabisulfite solution and sulfur dioxide before cut into pieces, halves and as whole. Then dates were dried at 50, 55, 60 and 65°C, respectively till ~20% moisture content and examined the physical and chemical properties of dried dates.
Results: Moisture content of Siwi and Sakkoti at the khalal stage was 56.90 and 51.72%, respectively, while total sugars were 79.76 and 75.74%, respectively on dry weight bases. The color of dates Hunter (L and b) were the highest of treated with meta-bisulfate solution or sulfur dioxide and the lowest of color date observed (Hunter, a) comparing with control and ascorbic acid.
Conclusion: The pretreatments indicated that the dipping dates in sodium meta-bisulfate solution or sulfur dioxide then, dried at 60˚C produce high quality parameters of semi-dry dates comparing control and ascorbic acid.
Keywords: Date palm; Sakkoti; Siwi; ascorbic acid solution; endogenous enzymes; sodium metabisulfite solution; sulfur dioxide.