Colorimetric method development and Validation for estimation of lactose in milk

Abstract

Lactose is one of the major carbohydrate found in milk. Several spectrophotometry methods were carried out for the determination of lactose in milk samples. Here we validated a simple, accurate, specific and precise visible spectroscopy method according to the ICH guidelines for the estimation of lactose in milk (buffalo milk and packet samples). It is a simple and rapid technique for the estimation of lactose in fluid milk and whey. In this method Trichloroacetic acid (TCA) as a precipitating agent. The color development is based on the reaction of picric acid with lactose in the presence of phenol, sodium hydroxide and sodium bisulfate. The λmax of standard lactose was found to be 482 nm. The exhibited the linearity in the concentration range of 10-0μg/ml with a correlation coefficient of 0.999. The precision studies of the method revealed results of % R.S.D values less than 2% indicating that the developed method is precise. The percentage recovery for the proposed method was found to be 99%.