Production of black instant tea powder and evaluation of its physicochemical and anticancer properties

Date

2023-8

Author

Çifte, Neriman Ezgi

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Black tea is the most consumed beverage in the world behind water. During black tea production, a substantial amount of waste, known as black tea fiber, was generated. In this study, black tea waste fibers were valorized to produce various instant teas, a growing and increasingly popular product category of black tea. The water-to-tea ratio of 30:1 ml/g, the superfine particle size range (<100 μm), the infusion conditions at 100 ℃ for 6 min and at 25 ℃ for 2 h for the hot and cold infusion methods, respectively, were set as operational parameters to maximize the extraction yield of black tea waste fibers. Instant tea powders produced by freeze drying were also mixed with ginger and sage using superfine grinding to enhance their functional properties. Instant black teas enriched with ginger and sage were characterized based on the analyses of moisture content, hygroscopicity, color, morphological, solubility and turbidity. In addition, instant teas were investigated for their antioxidant capacities, total phenolic content and the composition of catechins (epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate), theaflavin, thearubigins, gallic acid, caffeine and theanine. Instant teas produced by the hot infusion method had a higher antioxidant capacity and total phenolic content than those obtained by the cold infusion method for the same formulation (p<0.05). Instant black tea powders also demonstrated anticancer potential in a concentrationdependent manner against prostate cancer cells (PC3, 22Rv1 and LNCaP), brain tumor cells (U87MG and A172) and breast cancer cell (MCF7) in the in vitro studies.

Subject Keywords

instant tea, black tea waste fiber, superfine grinding, phenolics, anticancer

URI

https://hdl.handle.net/11511/105202

Collections

Graduate School of Natural and Applied Sciences, Thesis