A new method for discriminating milk heat treatment

A new fluorimetric FAST (Fluorescence of Advanced Maillard products and Soluble Tryptophan) method was developed to estimate the intensity of heat treatment applied to milk. The method is based on quantification of protein denaturation by means of Trp fluorescence (F-Trp) and accumulation of fluorescent Maillard products (F-AMP) in the pH 4.6-soluble fraction of the milk. We validated the FAST method on experimental industrially processed milk samples (various sterilization systems and processing at various temperatures and holding times) by comparison with three HPLC techniques standardized for quantification of beta-lactoglobulin, furosine and lactulose. The FAST technique was demonstrated to be as efficient as the determination of the three chemical indicators to predict pasteurization and sterilization effects and was better for discriminating the type of heat process. The FAST method is rapid, sensitive and low-cost, and allows distinguishing milk heat-treatments from thermization to in-bottle sterilization and in estimating the resulting nutritional damage. (C) 2002 Elsevier Science Ltd. All rights reserved.