A simplified enzymatic method for total cholesterol determination in milk

Methods for determination of milk cholesterol concentration were compared, with particular emphasis on an enzymatic method (ME). Bovine and human milk samples (n = 40) were pre-treated and analysed by three different protocols: (i) IDF Standard with gas chromatography (GC); (ii) direct saponification (DS) and GC; (iii) DS and ME with spectrophotometric determination. A simplified method (DS + ME) was developed with an acceptable coefficient of variation. The cholesterol concentration values assessed by DS + ME were higher compared with DS + GC. There were no statistically significant differences between the results obtained by the enzymatic and IDF method (P = 0.09). The mean cholesterol concentrations in bovine and human milk were 16.71 +/- 4.21 mg dL(-1) and 2.80 +/- 0.65 mg dL(-1), respectively. The new method developed was less time-consuming and more economical, and could be suitable for large-scale studies. High recovery (95%) obtained by ME indicates that the results are reliable and could be the basis for routine analysis. (C) 2015 Elsevier Ltd. All rights reserved.