بررسی امکان تولید و پایداری نوشیدنی چای سرد از خاک چای سیاه

In Iran, there are about 10% losses in black tea processing, which is called tea dust. Tea dust is produced through black tea screening, during the last stage of production. In this research, regarding the increasing demand for new beverages, the production of iced tea beverage using black tea dust was investigated. Process of iced tea involved tea solid extraction and then mixing with edible acids, flavors, sugars or non-nutritional sweeteners. The effects of extraction temperature and time on the extractability were examined. Tea cream and haze of extracts were also determined using gravimetric and spectrophotometric methods, respectively. The extracted components, which cause tea cream and haze formation in final product increased with increasing of temperature. A sharp increase was observed when extraction temperature increased from 50 to 60^oC. There was no significant difference (P<0.01) between treatments regarding tea cream and haze formation in 40 and 50^oC, but above 50^oC was different significantly. Iced tea beverage was flavored with different essential oils and then their acceptability was evaluated by sensory panel in a multiple comparison method. Standard physical and chemical experiments, color stability (with ICUMSA method) and haze changes for beverages during storage were monitored for 2 months. The results indicated that produced iced tea beverages (P<0.01) were stable.