STUDIES REGARDING THE EFFECT OF BOILING ON COW MILK QUALITY WITH ANALYSIS OF SOME PHYSICO-CHEMICAL CHARACTERISTICS AND THE SOMATIC CELL COUNT PUBLISHEDMihaela OSTAN, Iuliana CREŢESCU, Venesa PLOSCAR, Mihaela CAZACU, Olga-Alina RADA
Due to their chemical composition and high degree of assimilation, milk and dairy products play an important role in rational human nutrition and are some of the easiest assailable animal protein sources. They are foods with a particularly valuable plastic role in the nutrition of both children and adults and elderly. There are numerous studies and research showing that milk may undergo various changes during preparation (by boiling or microwaving) or during processing, heat treatment methods involving moderate or severe and can lead to undesirable changes. The goal of this paper is to point out the effect of boiling on density, surface tension, fat content, solids-non-fat content, dry matter and number of somatic cell for the evaluation of the correlations between these parameters by analysing fresh milk and boiled milk. The material used in the study was represented by five individual samples of milk, originated from clinically healthy cows. The milk was divided into two portions, the second being subject to heat treatment by boiling. Were analyzed a total of 10 samples (5 fresh milk and 5 boiled milk). The chemical composition of the milk was determined by means of the apparatus MilkoScan S54B, somatic cell count (NSC – number of somatic cell) by cell counter MT-02®, density by picnometric method and surface tension by stalagmometric method. To process experimental data and extract as much information from the results was used the technique of statistical principal component analysis (PCA), realizing all the necessary processing with software XLSTAT, Version 2015.1. Fresh milk fat ranged between 3.30 and 5.29 [g%], while for boiled milk between 3.51 and 5.16 [g%]. Fresh milk solids-not-fat ranged between 9.13 and 10.24 [g%], while for boiled milk was between 9.41 and 10.71 [g%]. NSC for fresh milk ranged between 100.000 and 310.000 cell/ml, for boiled milk between 50.000 and 115.000 cell/ml.
cow milk, somatic cell count, physico-chemical parameters