Determination of Residual Catechins, Polyphenolic Contents and Antioxidant Activities of Developed Theaflavin-3,3'-Digallate Rich Black Teas

Abstract This study was carried out to characterize total residual catechins and their fractions, polyphenolic contents and antioxidant activities of black teas enriched with high levels of theaflavin-3,3'-digallate. The made teas were processed from eleven selected cultivars. A comparative study was carried out between the processed teas and those from commercially grown Kenyan cultivars in relation to the above chemical parameters. A correlation matrix analysis was also conducted to find out whether a relationship existed between the antioxidant activities and the said chemical parameters. The total residual catechins were found to range between 3.10% and 8.08%. The total polyphenol levels varied between 19.00% and 28.90%, while the antioxidant activities of the teas ranged from 82.70% to 91.70%. There was a significant p < 0.001 correlation between the antioxidant activity and total polyphenols (r = 0.8948). There was also a high correlation p < 0.001 between the antioxidant activity and total catechins (r = 0.8878). Out of the four catechin fractions, the antioxidant activity correlated most with EGCG (r = 0.8774). The total polyphenolic contents and antioxidant activities for most of the cultivars were comparable to those of the green tea reference standard. From the figures obtained, it can be concluded that the most of the newly developed black teas of the selected cultivars have higher quality and enhanced antioxidant activities and that they can be recommended for commercial production. S. Kimutai et al

Quantitative genetic parameters in tea (Camellia sinensis (L.) O. Kuntze): I. combining abilities for yield, drought tolerance and quality traits.

The combining abilities for yield, drought tolerance and quality related traits inCamellia sinensis were estimated using a 4 x 4 full diallel mating design. There was significant phenotypic variation for the nine traits measured among the progeny and their parents. Generally, parents with good combining ability produced progeny with above average performance for all the traits evaluated. The general combining ability (GCA) effects were significant for all but one black tea quality trait, TF:TR, while specific combining ability (SCA) effects were significant for fermentability, pubescence and bud weight. All the traits but TF:TR however were predominantly governed by additive gene effects. Strong maternal influence for all traits was evident except for thearubigins and bud weight signifying the importance of the choice of female parents in tea breeding programmes targeting yield, abiotic stress related traits and processing of black tea and special tea products like the silvery tips. Significant non-additive effects were demonstrated by all traits apart from yield, TF:TR and bud weight. However, only drought tolerance, TF and pubescence exhibited unidirectional dominance effects. The results show that the assessed traits are highly heritable and guided breeding and judicious clonal selection would lead to further tea improvement. Although no trait can be treated singly, utilization of open pollinated seed targeted towards improvement of yield and black tea quality traits particularly high levels of total polyphenols and pubescence aimed at developing a designer clone for specialty tea product would suffice given judicious choice and inclusion of suitable progenitors in seed orchards. It is inferred that the basic information about combining abilities is valuable for breeding of elite cultivars

Fortification of alcoholic beverages (12% v/v) with tea (Camellia sinensis) reduces harmful effects of alcohol ingestion and metabolism in mouse model

Background: An animal model was used to study the health benefits inherent in tea fortified alcoholic beverages fed to laboratory mice. Objectives: An investigation of the effects of tea fortified alcoholic beverages 12% alcohol (v/v) on antioxidant capacity and liver dysfunction indicators in white Swiss mice including packed cell volume (PCV), albumin, total protein, alkaline phosphatase (ALP) and glutathione (GSH) was carried out. Methods: Plain, black, green and purple tea fortified alcohols were developed with varying tea concentrations of 1, 2 and 4 g/250 mL in 12% v/v. Control alcoholic beverages without teas were also developed. A permit (number IRC/13/12) was obtained for the animal research from the National Museums of Kenya, Institute of Primate Research prior to the start of the study. Alcoholic beverages were orally administered every 2 days for 4 weeks at 1 mL per mouse, and thereafter animals were euthanised and liver and blood samples harvested for analyses. Assays on body weight (bwt), packed cell volume (PCV) albumin, total protein, ALP and GSH were performed. Results were statistically analysed using GraphPad statistical package and significant differences of means of various treatments determined. Results: Consumption of tea fortified alcohols significantly decreased (p=0.0001) bwt at 0.32-9.58% and PCV at 5.56-22.75% for all teas. Total protein in serum and liver of mice fed on different tea fortified alcohols ranged between 6.26 and 9.24 g/dL and 2.14 and 4.02 g/dL, respectively. Albumin, ALP and GSH range was 0.92-2.88 mu g/L, 314.98-473.80 mu g/L and 17.88-28.62 mu M, respectively. Fortification of alcoholic beverages lowered liver ALP, replenished antioxidants and increased liver albumin, improving the nutritional status of the mice. Conclusions: The findings demonstrate tea's hepatoprotective mechanisms against alcohol-induced injury through promotion of endogenous antioxidants. The beneficial effects of tea in the fortified alcoholic beverages could be used to develop safer alcoholic beverages