NON-DESTRUCTIVE STUDY OF ACID MILK COAGULATION

Abstract

The acid coagulation is the main processing step in the yoghurt production and has a great impact on yogurt texture, microstructure and rheology, contributing to the overall sensory and visual product perception by the consumer.  The objective of this paper was to study the different stages of acid gel formation by turbidimetric and conductivimetric methods. The non-destructive methods used allow the differentiation of three regions : latent phase( рН = 6,3 ÷ 6,0), exponential phase (рН = 5,9 ÷ 5,4) and   phase of protein structure formation of demineralized casein micelles (pH = 5,3 ÷ 4,6). The mathematical model obtained by the three-parameter sigmoid function can be used in future studies to predict the change in conductivity during acid coagulation.