Introduction. There is a growing demand in the international market for
excellent-quality dates of cultivars such as ‘Barhee’ that are consumed at the bisir
stage. Materials and methods. The effects of GA3, BA and NAA
postharvest dipping treatments at different concentrations on the quality characteristics
of bisir ‘Barhee’ dates during cold storage were investigated. Results and
discussion. The total soluble solids (TSS) concentration was lower in the BA- and
NAA-treated fruit than in control fruit. Similarly, the GA3-treated fruit at
150 mg·L-1 contained a lower TSS concentration than control fruit. The
GA3 at 150 mg·L-1, BA at 60 mg·L-1 and NAA at (100 and
150) mg·L-1 increased vitamin C concentration compared with other treatments.
Acidity and total phenol concentrations were not affected by any of the treatments. The
date soluble tannin concentration was higher than control fruit only in the dates treated
with 20 mg BA·L-1. The weight loss % was lower in the BA-treated fruit at (20
and 60) mg·L-1 compared with all other treatments, while GA3
treatment at 50 mg·L-1 increased fruit weight loss % compared with control
fruit. The percentage of dates at the rutab stage (index for fruit ripening) was lower for
fruit treated with GA3than for control fruit. Also, the rutab stage % was lower
for fruit treated with BA at 40 mg·L-1 and NAA at 150 mg·L-1
compared with control fruit. The TSS concentration decreased during storage from the
initial day to day 20. However, there were no further decreases in the TSS concentration
after (40 and 60) days of storage. The acidity concentration was slightly increased during
storage. The vitamin C concentration increased until 40 days of storage, then a slight
decrease occurred. The total phenol concentration decreased after (40 and 60) days of
storage compared with the initial level. The soluble tannin concentration slightly
increased at day 20 but sharply decreased after (40 and 60) days of storage compared with
the initial level. Both weight loss and rutab stage % gradually increased during storage.
There were significant interaction effects between growth regulators and storage period on
TSS, vitamin C concentration, weight loss and rutab stage %.
