evaluation of some physicochemical properties of milk caused by acidification

The objective of this study was to evaluate changes in some physicochemical properties of milk during acidification. The milk samples were analyzed for titratable acidity expressed as % lactic acid (LA), pH, electrical conductivity (EC) and lactose content. In fresh milk LA and pH exhibit a weak negative correlation (r = -0.3210). When acid production starts, LA increases proportionally, whereas the pH decreases (r = -0.8043). The acidifying process induced concomitantly an increase in EC. The decrease in pH from 6.578±0.088 to 5.732±0.195, and in lactose content from 5.469±0.256g% to 4.97±0.385g% was accompanied by an increase in EC from 5.337±0.434 mS/cm to 5.940±0.493 mS/cm.