ENZYMATIC-HYDROLYSIS, EXTRACTION, AND QUANTITATION OF RETINOL AND MAJOR CAROTENOIDS IN MATURE HUMAN-MILK

An improved method for enzymatic hydrolysis, extraction, and high perf ormance liquid chromatography (HPLC) separation of major carotenoids a nd retinol of mature human milk is described. After pretreatment with bile salts and protease, carotenoids and retinol are released by lipas e treatment followed with brief chemical saponification. The HPLC meth od provides enhanced peak resolution and improved elution profiles. Th e procedure is nondestructive to provitamin-A carotenoids while effect ively hydrolyzing retinyl esters. Using this method, we were able to s ignificantly increase the recovery of both beta-carotene and retinol f rom human milk over previously published procedures. The method is sen sitive to picomolar quantities of carotenoids and retinol. Retinol, lu tein/zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, and bet a-carotene are effectively recovered and quantitated from a single 1-m L sample of milk. (C) Elsevier Science Inc. 1998.