M.A. Thesis:

Investigation of fiber extraction from the tea plant waste and the possibility of using it in yogurt formulation

Tea (Camellia Sinensis) is an evergreen shrub, perennial, dicotyledonous angiosperm and belongs to Parital order, Theaceae family and Camellia genus. Tea is in the form of plant, shrub or tree. This plant is native of South-East of Asia and grows in hot and humid areas. Tea is grown on about 32 thousands Hectares of lands in north of the country. Cold autumn and winter reduce efficiency period of the crop to 6 months. Due to the high level of tea cultivation in the country, restrictions in harvesting seasons and non-standard methods of harvesting, tea farm’s waste is too much which is rich of fiber. The objectives of the present study were to determine the amount of raw fiber in the tea farm’s waste, evaluate the effect of different harvesting times on the amount of fiber and predict the influence of different percentages of fiber extracted from leaf and stem on the yogurt’s rheological properties, sensory acceptance, color, antioxidant activities and the amount of phenolic compounds. For this purpose, experiments have been set up in two separate phases and in triplicate in Islamic Azad University of Sabzevar in 1395. In the first phase which was done as factorial, two factors of harvest time (spring, summer, autumn) and the type of plant (leaves, stem) were investigated and the highest amount of raw fiber was determined. In the second phase, which was done as split plot in time, the main factor was the type of fiber (fiber stem and leaves fiber and sample control) and the Subplot factor was time (0, 7, 14 and 21days) during the storage. Duncan test for means comparison were used to determine significant difference at p<0.05. The data were analyzed by SAS software. The results showed that the amount of raw fiber in the stem was more than in leaves. At the time of harvest, autumn harvest had more percent of raw fiber than other harvests. In evaluating sensory properties, parameters like flavor, aroma, texture and color remain unaffected by percentage of stem fiber or leaves fiber, although the highest amount of these properties were observed in yogurt contains 0.5% of stem fiber. Increasing the percentage of fiber in both of stem and leaves, reduced sensory properties. Increasing the percentage of stem and leaves fiber, reduced sensory properties. The most amount of acidity, synersis and a* was observed on 21st day. On the 7th day the lowest amount of pH and L* and the highest viscosity and phenolic compounds were observed. The yogurt contains stem fiber had the lowest synersis, the highest viscosity, a* and b* while the most amount of the phenolic compounds and the antioxidant properties were observed in yogurt contains leaves fiber. In general, the results of this study showed that the application of 0.5% of autumn’s stem fiber in the yogurt, had the highest quality properties. According to the results, we can use the tea farm's waste as a rich source of fiber and antioxidant, to improve public health and develop agricultural economy.

Keywords: Tea, Fiber, Waste, Phenolic compounds, Antioxidants, Rheology