Quality Control of Vinegar by TN Measurement

Introduction

Measurement of the TN (total nitrogen) concentration in a food can make available information on the concentrations of nitrogen compounds within that food, such as proteins and amino acids. Vinegar is a cooking ingredient which is made from materials such as grains or fruit, and the amount of proteins and amino acids that originate from such materials greatly affect the taste of the vinegar. It is therefore possible to check the quality of vinegar with the concentration of proteins and amino acids by TN measurement. The Kjeldahl method, which is widely used to measure the amount of proteins in food, requires multiple reagents to treat each sample as well as processes such as digestion and distillation. Measurements therefore require work by operators for over several hours. The TNM-L total nitrogen unit for Shimadzu total organic carbon analyzer utilizes the thermal decomposition-chemiluminescence method, enabling rapid measurement taking only about 5 minutes per measurement without reagents. If an autosampler is used, automatic measurement of multiple samples is possible as well. This application news introduces example TN measurements of various vinegar types using Shimadzu TOC-L_CPH total organic carbon analyzer and TNM-L total nitrogen unit.

December 28, 2017 GMT