The Use of Mangosteen Pericarp (Garcinia mangostana L.) Extract to Fortify the Green Tea Drink Enchanced Antioxidant Activity.

Mangosteen pericarp and tea contain high polyphenol content that has disease preventive properties. This study aimed to utilize mangosteen pericarp for producing added-value product, to evaluate polyphenols stability in green tea drink with mangosteen pericarp extract, and to evaluate the effect of citric acid to the polyphenols stability in green tea drink with mangosteen pericarp extract. Mangosteen pericarp was hot air dried at 50oC until the moisture content reached 7.43±0.10%. Dried mangosteen pericarp was soaked in distilled water, then the total polyphenol content, DPPH, and FRAP of the extracted solution were analyzed. The extract was added into green tea drink at seven different concentrations (0.1-0.7%). The optimum concentration into green tea was evaluated by sensory test, and then it was mixed with gradual concentrations of citric acid (0.06, 0.1, and 0.2%). The results showed that the total phenolic compound, DPPH and FRAP of the extract were 127.39±1.19 mg GAE/ml sample, 44.92±0.68 mmol TE/ml sample, and 21.49±0.13 mM asorbic acid/ml sample, respectively. The optimum concentration evaluated by sensory test was 0.4%. The mixture of green tea drink with 0.4% mangsteen pericarp extract and 0.2% citric acid showed the lowest pH (2.79), the highest total phenolic compound (25.48±0.38 mg GAE/ml sample), DPPH (57.86±1.25 mmol TE/100 ml sample), and FRAP (5.68±0.33 mM asorbic acid/ml sample) compared with the other treatments (p<0.05). Therefore, mangosteen pericarp extract can be applied in green tea drink and provided more polyphenol content for the product. In addition, citric acid enhanced the stability of polyphenol in green tea drink.