Abstract
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 GA(3), 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 GA(3)-treated fruit at 150 mg.L-1 contained a lower TSS concentration than control fruit. The GA(3) 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 GA(3) 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 GA(3) than 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 %.