Utilizing Tea Industry By-products to Improve Instant Tea Aroma

Abstract

Refuse tea, industrially recognized as Broken Mixed Fannings (BMF) is the most economical raw material that can be used to manufacture instant black tea powder. The commercial interest lies in determining the ideal geographical regions to source BMF to produce instant tea with the desired quality. This study aimed to determine the effect of tea growing elevation on quality parameters of BMF and instant tea produced from BMF. Instant tea was prepared from BMF obtained from eight tea estates from the three growing elevation categories in Sri Lanka i.e., high grown (HG) ( > 600m MASL) , mid grown (MG) (300m-600m MASL) and low grown (LG) (< 300m MASL).Total polyphenol content (TPC) in both instant tea and BMF in HG regions were significantly higher (p< 0.05) than MG and LG regions. TPC of instant tea was significantly higher ( p< 0.05) than that of BMF. Haze value of instant tea from HG region was also significantly higher than that of MG and LG regions. A significant positive correlation (p< 0.05, r= 0.77) was also found between TPC and haze value in instant tea.Analysis of the aroma profile by HS-SPME/GC-MS revealed that 100 to 150 volatile compounds are present in the headspace of each instant tea and BMF samples. Major aroma compounds present in Ceylon black tea such as (Z)-3-hexenol, linalool, geraniol, phenylacetaldehyde and 2-phenylethyl alcohol were detected in BMF, but only a few of those compounds such as phenylacetaldehyde, 2-phenylethyl alcohol and benzyl alcohol remained in instant tea. Aroma profile analysis showed that the most important volatiles in tea have been lost due to evaporation and therefore possibilities exist to produce aroma condensates that resemble the aroma of Ceylon black tea as a byproduct when manufacturing instant tea.