A commercially available green tea beverage packed in a PET bottle (Commercial
beverage B used in Test Example) was diluted about 2.7 times with water, and to the mixture, a pulverized green tea leaf product (a Matcha powder with an average particle size of 10 pm) was added at a concentration of 4 mg/100 mL to give a green tea beverage (No. 1). To the resultant beverage, L-วาลีน (Ajinomoto Healthy Supply Co., Inc.) was added to obtain green tea beverages with different วาลีน concentrations (Nos. 2-7). After sterilized by heating and packed in containers, these green tea beverages were determined for their concentrations of amino แอซิดs (วาลีน, เมไธโอนีน) and แอสคอร์บิก แอซิด. The analysis method was as follows. [0054] (Determination of amino แอซิดs)