Method for determining total amount of free amino acids in tea drink

Abstract

The invention provides a method for determining the total amount of free amino acids in a tea drink. The determination method comprises the following steps: (I) preparing reagents, namely preparing anL-glutamic acid standard solution, preparing a 2% ninhydrin solution and preparing a buffer solution having a pH value of 8.0; (II) making an amino acid standard curve; and (III) sample determination. The step of making the amino acid standard curve in the step (II) at least comprises the following steps: (1) making a standard curve of different content intervals according to high and low partitions of the amino acid contents in the process of making the standard curve; and (2) increasing concentration points on the curve while making the standard curve, wherein the quantity of the concentration points is increased to 12-20. According to the determination method disclosed by the invention, the concentration points on the curve are increased and the partitions are divided when the standardcurve is made, and the preferred scheme of the partitions refers to respectively making a low-content interval standard curve and a high-content interval standard curve, so that the determination result of the total amount of the free amino acids is accurate.

Description

technical field [0001] The invention relates to an amino acid detection technology in tea beverages, in particular to a method for determining the total amount of free amino acids in tea beverages with increased concentration points and divisions when making a standard curve and accurate measurement results. Background technique [0002] Free amino acids are an important quality component in tea beverages, and their content directly affects the taste of tea beverages—freshness. Therefore, it is particularly important to accurately determine the total amount of free amino acids in tea beverages. However, the levels of free amino acids in different types of tea beverages are different, so it is necessary to study their detection methods. [0003] At present, the determination of the total amount of free amino acids mainly adopts GB / T 8314-2013 "Determination of the total amount of free amino acids in tea". There is no standard method for the determination of the total amount o...

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Problems solved by technology

[0003] At present, the determination of the total amount of free amino acids mainly adopts GB / T 8314-2013 "Determination of the total amount of free amino acids in tea". There is no standard method for the determination of the total amount of free amino acids in tea beverages, and we have found some Problem: First, when making the standard curve, only six points of 0.00mg / mL, 0.20mg / mL, 0.30mg / mL, 0.40mg / mL, 0.50mg / mL, and 0.60mg / mL were selected in the national standard. The span from 0.00mg / mL to 0.20mg / mL is too large, and the linear relationship of the resulting standard curve is not ideal, so it is difficult to accurately determine the total amount of free amino acids in tea beverages, especially when the content is low , it is more difficult to obtain accurate results; second, in this standard, there is no need to add water before the boiling water bath, which has high requirements for operation, and a little carelessness will lead to great differences in the data of concentration points

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