Aplicação de fosfatos e citrato de sódio para estabilização do leite

Abstract

The thermal stability of milk is defined as the time required for the milk to show visible protein coagulation at a given temperature and pH.For this reason, the milk destined for UHT processing needs to be stable at all stages of the process, so that it does not cause damage to the equipment used and so that it does not present instability during the entire shelf life of the final product. The use of sodium phosphates in UHT processing improves the stability of milk, and each phosphate can cause a greater or lesser increase in stability. In this work, the influence of the addition of different sodium phosphates (such as different sizes of chains and phosphorus radicals, alone or in combination, to pasteurized milk) was evaluated in order to improve its stability when subjected to thermal processing. of sodium phosphates were also tested for their stability when fresh and also stored refrigerated for seven days. In each treatment, analyzes of the alcohol test were performed, in which the alcoholic degree varied from 72°GL to 98°GL and the results of these analyzes were visualized in digital microscopic reading, by the ProScope equipment, and also by visualization through the human optic. The milks added with DSP + TSP – mixture of sodium diphosphate and sodium triphosphate, TSPP- sodium tetra pyrophosphate showed greater stability to ethanol, being the most suitable for use as a stabilizer in the UHT process. All the sodium phosphates tested in this work improved the stability of milk in the alcohol test when compared to the control treatment (without the addition of phosphates), evidencing the direct relationship between the addition of sodium phosphate and the colloidal stability of milk. There was no statistical difference (p = 0.54713) regarding the stability index of milks added with phosphates in relation to whether they were fresh or stored refrigerated for seven days. Regarding the visualization of the analyses, there was a significant difference between the two visualization methods (human optics and electron microscopy). Direct visualization tends to overestimate the stability and turning point of milk, which can lead to technological problems compared to reading using a ProScope microscope.