Effect of Different Somatic Cell Levels on Nitrogen Components of Yoghurt Milk and Probiotic Set Yoghurt During Storage Life

Subject Areas : International Journal of Agricultural Science and Research

A. Bavaria ¹ (nadarad)
H. Ezzatpanah ² (nadarad)
M. Aminafshar ³ (nadarad)
M. A. Mohammadifar ⁴ (nadarad)

Received: 2014-12-02 Accepted : 2014-12-02 Published : 2012-05-14

Keywords: Nitrogen Components, Probiotic Set Yoghurt, Proteolysis, Somatic Cell (SC) Level, Storage Life, Yoghurt Milk,

Abstract :

Nitrogen components of yoghurt milk samples and resulting probiotic set yoghurt weredetermined. Analyses included total nitrogen (TN), non-casein nitrogen (NCN), non-proteinnitrogen (NPN), casein nitrogen (CN) and proteolysis index (PI). Yoghurt samples wereanalyzed 1, 7, 14 and 21days after production and storage at 5±1°C. TN, CN and PI contentsof yoghurt milk samples with high Somatic Cell SC level were lower than yoghurt milk withlow SC (p<0.05). NCN and NPN concentrations of yoghurt milk increased by the elevationof SC level, however differences between low and medium milk samples were notsignificant. During storage life, TN and CN contents of all yoghurt samples decreasedsignificantly. NCN and NPN concentrations of probiotic yoghurt samples increased (p<0.05)after 21 days. It was concluded that SC level elevation in milk decreased casein as apercentage of true protein in the resulting probiotic yoghurt throughout storage for 21 days