Factor analysis as a tool to estimate association among individual proteins and other milk components with casein micelle size and cheese yield

Análise fatorial como ferramenta para estimar a associação entre proteínas individuais e outros componentes do leite com o tamanho das micelas de caseína e massa seca de queijo

ABSTRACT

The present study attempted to identify individual milk proteins and other milk components that are associated with casein micelle size (CMS) and dry matter cheese yield (DMCY) using factor analysis. Here, we used 140 bulk tank milk samples from different farms. Milk composition was determined using a Fourier transform infrared equipament. The individual milk proteins were (α_S-casein, β-casein, κ-casein, β-lactoglobulin and α-lactoalbumin) measured by their electrophoretic profile. The CMS was estimated by photon correlation spectroscopy, and the DMCY was determined using reduced laboratory-scale cheese production. Factor analysis partitioned the milk components into three groups that, taken together, explain 68.3% of the total variance. The first factor was defined as “CMS”, while the second as “DMCY” factor, based on their high loadings. The CMS was positively correlated with protein, casein, non-fat solids and α_S-casein and negatively associated with κ-casein and β-lactoglubulin. DMCY was positively correlated with fat, protein, casein, total solids and negatively correlated with α_s-casein. These results indicate that the variation of individual milk proteins may be an important aspect correlated to milk quality and cheese production.

Keywords:
κ-casein; α_s-casein; β-casein; α-lactalbumin; β-lactoglobulin