Page 23 - KVIS Book

LIS04I

Colorimetric Quantification of Tryptophan from Thai
Eggplant Extract

Anupap Chauyjaroensuk, Nalina Rawewonganothai, Sanchayapol
Lewkasemsarn
Kamnoetvidya Science Academy, Thailand
Supervisor: Sakol Warintaraporn
Email: 5900069@kvis.ac.th

Tryptophan is an important amino acid for our bodies, however, excessive tryptophan
intake can cause drawbacks. Thus, tryptophan quantification in samples is crucial.
Nevertheless, quantification of tryptophan with simple method, plain analysis,
affordable chemicals and high specificity is a challenging subject. In this research, the
tryptophan assay is created by the reaction of chlorogenic acid which is a natural
compound in many vegetables, such as burdock root and Thai local plant like Thai
eggplant. In basic conditions, the extract of those plants can react with tryptophan and
yield red solution; this reaction specifically happens with only tryptophan. As a result,
Thai local plant extract gives a similar result to the preliminary research. Then, this
research is tested on amino acids other than tryptophan to simulate the real situation
with many amino acids present. The research also aims to develop analytical method
to quantify tryptophan concentration by using Thai eggplant extract to construct
calibration curve of a mixture of Thai local plant extract and a variety of pure
chlorogenic acid concentration to determine chlorogenic acid concentration in Thai
eggplant extract. The concentration of chlorogenic acid will be used in construction of
calibration curve between tryptophan in various concentration with Thai eggplant
extract. Then, the expected detectable interval of tryptophan concentration is
examined.

Keywords: tryptophan, colorimetry, quantification, chlorogenic acid, thai eggplant