Antioxidant Activity of Different Forms of Green Tea : Loose Leaf , Bagged and Matcha

Green tea is commercially available in three forms: loose leaf, bagged and powdered. The objective of this study was to compare the radical scavenging capacity of different forms of green tea like loose leaf (3), bagged (2) and powdered matcha (2) of various brands. The green tea forms were prepared at 95-100 °C for 5 min., to mimic conditions usually used for tea preparations at home. The comparison of combined IC50 values of different green tea forms (loose leaf, bagged and matcha) showed no significant difference in their radical scavenging activity except bagged tea that exhibited slightly more DPPH radical scavenging potential as compared to matcha. Individually, the Bud white loose leaf demonstrated highest antioxidant activity followed by Laplant bag, Lipton bag, Laplant loose, Gourmet matcha, Wow matcha and Lipton loose. These findings revealed that on the basis of form, it may not be possible to generalize which form of tea whether loose leaf, bagged or matcha, is more effective in scavenging free radicals. Current research in Nutrition and Food Science Journal Website:www.foodandnutritionjournal.org ISSN: 2347-467X, Vol. 06, No. (1) 2018, Pg. 35-40 CoNTACT Amit Sehgal sehgalamitres@gmail.com Department of Zoology, School of Bioengineering and Biosciences, Lovely Professional University, Phagwara 144411, India. © 2018 The Author(s). Published by Enviro Research Publishers This is an Open Access article licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License (https://creativecommons.org/licenses/by-nc-sa/4.0/ ), which permits unrestricted NonCommercial use, distribution, and reproduction in any medium, provided the original work is properly cited. To link to this article: http://dx.doi.org/10.12944/CRNFSJ.6.1.04 Article history Received: 13 November 2017 Accepted: 20 March 2018


introduction
Green tea is obtained from the dried leaves of tea plant Camellia sinensis and is one of the drinks gaining popularity throughout the world 1 .It is manufactured from newly picked leaves that are exposed to heat, and then pan fried or steamed prior to rolling or shaping and drying 2 .It is widely consumed, due to its refreshing taste, aroma and various other properties like antioxidant, anticarcinogenic, antimutagenic and antihypertensive [3][4][5][6][7][8][9][10] .All the above mentioned properties are mainly attributed to high polyphenolic content present in the green tea 11 .The catechins constitute the major part of the polyphenolic content in green tea, main catechins and its derivatives present are: (-) -epigallocatechin (EGC), (-)epigallocatechin 3-gallate (EGCG), (-) -epicatechin gallate (ECG), (-) -gallocatechin gallate (GCG) and (-) -epicatechin (EC) [12][13][14][15] .It is reported that EGCG is one of the major and biologically effective catechin of green tea 16 .FAROOq & SEHGAL, Curr.Res.Nutr Food Sci Jour., Vol.6(1) 35-40 (2018)   Green tea is commercially available in the market in three forms: Loose leaf, bagged and powdered (matcha).There have been few comparative studies conducted on different forms of tea and their association with antioxidant potential.It was demonstrated that antioxidant capability of different forms of tea (bagged and loose leaf) was similar at 80 0 C/5'17 but another study showed that maximum extraction efficiency for green tea bioactive compounds also depends on steeping time at constant temperature for different tea types i.e. 5' (powder), 15' (bagged) and 30' (loose leaf) at 80 0 C 18 .The powdered form of green tea revealed greater scavenging effect on the production of reactive oxygen species (ROS) in vitro compared with the same amount of loose leaf tea 19 .Matcha is a powdered form of green tea that is produced from shade grown tea leaves that are briefly steamed after harvesting and then grinded in a stone mill 19,20 .It is found to be effective in quenching reactive oxygen species, inhibition of blood glucose accumulation and stimulation of lipid metabolism 21 .The aim of this study was to assess and compare the effect of different forms of green tea such as loose leaf (Bud white, Lipton and Laplant loose), bagged (Lipton and Laplant bag) and powdered (Gourmet and Wow matcha) on their antioxidant potential at conditions usually used for tea preparations at home.

Sample Preparation
Different forms of green tea such as loose [Bud white (BW), Lipton loose (LL), and Laplant loose (LAL)], bagged [Lipton bag (LB) and Laplant bag (LB)] and matcha [Gourmet matcha (GM) and Wow matcha (WM)] of various brands were evaluated in this study.Various tea samples were prepared by adding 0.2 g of tea in 10 ml of distilled water and steeped for 5 minutes at 95-100 0 C. The hot water samples were filtered using Whatman's filter paper and the filtrate was used for further investigations 22 .

Antioxidant Potential DPPh Free radical Scavenging Assay
The scavenging activity of different tea extracts against stable DPPH free radical was examined spectrophotometrically.DPPH solution (0.3 mM) was prepared by dissolving DPPH in methanol.The optical density (OD) of DPPH solution was set between 0.8-1 by diluting it with 50% methanol.Different concentrations of tea extracts were added separately to 2 ml of DPPH solution 23 .After 30 minutes of incubation, the discoloration of the purple to yellow color was observed at 520 nm.Methanol was taken as blank and 2 ml of DPPH solution was taken as control.The test was carried out in triplicates.Radical scavenging potential was determined applying the following relationship: % Scavenging activity = A 520 (c) -A 520 (s) / A 520 (c) x 100 Where, A(c) = absorbance of control and A(s) = absorbance of sample.

ABTS Free radical Scavenging Activity
This assay depends on the ability of different substances to scavenge ABTS [2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)].The radical cation was generated by reacting ABTS stock solution (7 mM) with potassium persulfate (2.4 mM) in 1: 1 ratio.The reaction mixture was kept in dark for 16 hours at room temperature.The optical density (OD) of ABTS solution was set between 0.8-1 by diluting it with 50% methanol.Different concentrations of tea extracts were added to every 2 ml of ABTS solution 24 .After 30 minutes of incubation, absorbance of respective samples was taken at 745 nm.The scavenging potential of the test samples was determined by following equation: % Scavenging activity = A 745 (c) -A 745 (s)/A 745 (c) × 100, Where, A(c) = absorbance of control and A(s) = absorbance of sample.

Statistical Analysis
The data was expressed as mean ± S.D for triplicate readings.The inter group comparisons were performed by one way analysis of variance (ANOVA) succeded by Tukey's honestly significant difference test using SPSS software (version 18).FAROOq & SEHGAL, Curr.Res.Nutr Food Sci Jour., Vol.6(1) 35-40 (2018) The observations were considered statistically significant when the p-values are 0.05 or less.

results and Discussion
Antioxidant activity of different forms of green tea was determined using DPPH and ABTS tests as shown in Figure 1 and 2.

Fig. 2: ABTS radical scavenging activity of different brands and forms of green tea (mean ± sd, n=3). Different alphabets symbolize significant variation between different tea brands. Bud white (BW), Gourmet matcha (GM), Laplant bag (LAB), Laplant loose (LAL), Lipton bag (LB), Lipton loose (LL) and Wow matcha (WM) are various brands of different forms of green tea
The fluctuations in antioxidant activity of green tea from various brands were reported.This is in agreement with previous studies, which concluded that phytochemical content of tea is affected by the cultivation conditions, horticultural practices, cultivar, age of leaf, grade, geographical area, storaging and type of processing [25][26][27] .
The combined IC 50 values of different forms of green tea such as loose (Bud white, Lipton and Laplant loose), bagged (Lipton and Laplant bag) and matcha (Wow and Gourmet matcha) showed no statistical significant difference in both the antioxidant assays except in case of DPPH radical scavenging, bagged tea demonstrated a small but significant difference in radical quenching ability as compared to matcha as depicted in Table 1.The same study also showed that antioxidant potential and total phenolic content was found to be maximum for all green tea forms at 100 0 C/3', the bagged tea possess highest scavenging activity followed by powdered and then loose leaf tea 18 .In vivo studies demonstrated that regular consumption of green tea exerts protection against benzo(a)pyrene mediated toxicity in mice model 28,29 .
In the present work, no significant difference was found between the radical quenching ability of different forms of tea except bagged tea, which exhibited slightly more scavenging potential in case of DPPH radical.Interestingly, earlier studies also revealed that antioxidant capability of different forms of green tea were similar for steeping time of 5' and 10' at 80 0 C [17][18] .It was also suggested that high water temperature and short steeping time is best for extraction of tea bioactive compounds 18,30,31 .Our investigation was concentrated on short steeping time (5') and high water temperature (95-100 0 C) as these conditions mimic the household method of tea preparation.

Conclusion
The study on the antioxidant activity of different forms of commercially available green tea like loose (Bud white, Lipton loose and Laplant loose), bag (Lipton and Laplant bag) and matcha (Gourmet matcha and Wow matcha) prepared at 95-100 0 C and steeped for 5 min, showed no significant difference in the IC 50 value against DPPH and ABTS radical except bagged tea that displayed slightly more DPPH radical scavenging potential in comparison to matcha.But individually, BW (loose leaf) showed the highest antioxidant activity followed by LAB (bagged), LB (bagged), LAL (loose leaf), GM (powder), WM (powder) and LL (loose leaf).Moreover, this study reported it might not be possible to rank the radical scavenging potential on the basis of green tea form.