Antioxidant Potential of Sencha and Hojicha in Tea Bags and Tea Leaves

Choi, Xiao Chi (2018) Antioxidant Potential of Sencha and Hojicha in Tea Bags and Tea Leaves. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

Tea with scientific name Camellia sinensis is the second most consumed beverage worldwide next to water. In this research, green tea were selected in this study due to its rich source of polyphenols, mainly catechins. The method of preparing tea varies throughout the world and among types of tea. Water extraction was carried out because it is a common brewing process in domestic practice, therefore the results can be used to evaluate likely intake of antioxidant level form drinking tea by consumers. Hojicha and Sencha were used to study effects of water extraction time (5 minutes, 10 minutes and 15 minutes), temperature (60°C, 80°C and 100°C) and packaging (tea bags and loose leaves) on antioxidants level. The contents of total polyphenols, total flavonoids and antioxidant level was determined spectrophotometrically. Determination of carbohydrate content by Dubois colourimetric method and colour different in extracts were also determined. All result was analyzed by Minitab 17. The findings of this study showed that extraction efficiency of studied antioxidant compounds from green tea depended strongly on the infusion temperature, infusion time and packaging. For Sencha, the results showed highest Total Phenolic Content, TPC (66.05 mg GAE/g Sample), Total Flavonoid Content, TFC (23.04 mg CE/g Sample) and 1-1-Diphenyl-2-picryl-hydrazyl, DPPH (91.32 ppm VCE) when brewed for 10 minutes and 100°C in loosely packed form after optimized all factors. For Hojicha, the results showed highest TPC (78.23 mg GAE/g Sample), TFC (26.43 mg CE/g Sample) and DPPH (79.03 ppm VCE) when brewed for 10 minutes and 100°C in bagged form after optimized all factors. 60°C with 5 minutes showed the most inefficient in extraction of antioxidant compounds. This research provided optimal infusion parameter to extract antioxidant compounds from Sencha and Hojicha.