A comparative study on the determination of lactic acid in silage juice by colorimetric, high-performance liquid chromatography and enzymatic methods

Abstract

The determination of lactic acid in the silage juice of artichokes with different additives (formid acid, molasses and NaCl) by the colorimetric method and its comparision with the high-performance liquid chromatography and enzymatic methods was investigated. The lactic acid content of the artichoke with molasses (62.1 g kg−1) was higher than that of those with formic acid, or NaCl and without any additive (39.3, 33.0 and 43.2 g kg−1, respectively). However, this effect was not significant (P > 0.05). There were significant differences on the method of measuring lactic acid of the artichoke silages (P < 0.001). The use of the enzymatic method resulted in a higher (75.6 g kg−1) lactic acid content than when the colorimetric or HPLC methods were employed (with results of 42.0 and 28.9 g kg−1, respectively). However, the levels of lactic acid in silage juices found using the colorimetric and HPLC methods were not different, and recovery percentages, by using the colorimetric method, were satisfactory (103.78%), when the detection limit at maximum level (30 µg ml−1) was not exceeded. © 1999 Society of Chemical Industry