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Study of Productivity and Stability of Iced Green Tea Beverage from Green Tea Leave

Iced tea is a world popular beverage,for example about 80% of people in Italy and United States, consume iced tea as a thirsty-quenching beverage. However, it is also believed that iced tea contains health benefit components. Process of iced tea involved tea solid extraction and then mixing with edible acids, flavors, sugar or non-nutritional sweeteners. In this research, regarding to the demand market for new beverage, the possibility of production iced tea beverage using green tea leave was investigated and was extracted under predetermined conditions. The effects of extraction temperature and time on the extractability were examined. The results of extraction at various temperatures in sample demonstrated that the extracted solid yield increased steeply during the first 5-10 min of extraction, but gradually in next 10-30 min and after 30 min the extraction continued slowly. Tea cream and haze extract was also determined using gravimetry and spectrophotometric methods, respectively. The extraction components, which cause tea cream and haze formation in extract increased with increasing of temperature. A sharp increase was observed when extraction temperature increased from 50 to 60°C. There was no significant difference (p<0.01) between treatment regarding tea cream and haze formation between temperatures 40 and 50°C, but above 50°C was different significantly. Haze was significantly correlated to the tea cream in each extract. The linear regression coefficient for green tea leave extract was R2=0.969(p<0.01). Iced tea beverage was flavored with different essential oil and then that acceptability was evaluated by sensory panel analyzed with multiple comparison method. A standard physical and chemical experiment, haze changes for beverage during storing was monitored for 2 months. The results indicated that produced iced tea beverage (p<0.01) was stable