Modified Fleischmann's lactometer method for sweet whey total solids estimation

An empirical equation for calculating the percentage of total solids (TS) of sweet whey from renneted whole and skim milk based on a modified Fleischmann's equation and density (DW) by lactometer and fat content determinations is presented. The density of whey solids not fat (SNF) was first calculated (DSNF = 1.768 g mL−1) from analytical values. TS were determined (n = 34) gravimetrically and with the developed equation TS =1.152 Fat+2.302(Dw−1)Dw100; there was no significant difference between the mean values (0.00 ± 0.174 g 100 g−1, P > 0.05). The standard error of the mean for TS estimation by both methods was ≤0.06 g 100 g−1 for whole sweet whey samples. The method can be adapted to other whey fluids provided the SNF density is initially known and substituted in the basic formula from which the TS equation is derived.