Free and bound amino acids, minerals and trace elements in matcha (Camellia sinensis L.): A nutritional evaluation

Abstract

This study provides an overview of free and bound amino acids, minerals and trace elements content in matcha including evaluation of their dietary intakes. The analyses employed IEC and ICP-MS methods. Theanine followed by Glu, GABA, Thr and Me were the most abundant free amino acids. Considering bound amino acids, Glu, Asp, Leu, Lys, Arg and Val were the most frequent. The amino acid score (AAS) for matcha (40.2 %) is comparable to the AAS for wheat and sunflower proteins. Ile and Thr were evaluated as limiting amino acids. Regarding recommended daily allowance (RDA), the contributions of Cys and Met were up to 8%. Matcha is contributor to Adequate Intake (AI) or RDA for males in the following order: Mn (up to 15 %) > Cu > Fe (up to 7%). Similarly, for females, matcha contributes to RDA or AI values in this order: Mn (up to 19 %) > Cu > Zn (up to 5%). It has not been proved that matcha is a significant source of Se and Cr. A daily serving portion of 5 g does not contribute to PTWI (Provisional tolerable weekly intake) and PTMI (Provisional tolerable monthly intake) for Al, Sn, Cd and Hg.