Biochrom has developed an analytical procedure for the food and drink industry, using the Biochrom 30 Lithium high-performance amino acid analyser to analyse the theanine content in green tea leaves.
A molecule derived from the amino acid glutamine, theanine is typically found in tea (infusions of Camellia sinensis) and also in the basidiomycete mushroom Boletus badius.
Theanine's ability to enter the brain gives the molecule psychoactive properties, and the capacity to reduce mental and physical stress, produce feelings of relaxation, and improve cognition and mood when taken in combination with caffeine.
The effects are believed to be caused by the ability of theanine to increase GABA production in the brain.
To analyse the theanine levels of finely ground green tea leaves, the Biochrom 30 Lithium high-performance system is equipped with a 20cm x 4.6mm ID LiHP column and a set of Lithium Citrate buffers, to extract the free amino acid content from the tea leaves.
Biochrom recommends that the extracts are deproteinised with sulphosalicylic acid solution containing Norleucine as the internal standard.
The samples should be filtered through a 0.22-micrometre membrane.
40 microlitres were injected onto the column.
A standard high-performance elution program can be used with the instrument, to quickly separate the theanine from any other amino acids present in the tea.
The elute solution gives a high response when reacting with a Ninhydrin reagent, and the analysis method also allows the identification of 20 other amino acids naturally present in tea in a single run.
'The Biochrom 30 amino acid analyser has been specially developed for the analysis of rare, unusual amino acids or derived molecules for research purposes.
'The instrument is also ideal for carrying out routine analysis of amino acid content in food and feedstuff in quality control laboratories,' said Sally Bee, Biochrom's Amino Acid Analysis marketing manager.
