Liquid chromatographic method for the determination of beta-carotene from milk and cheese

Abstract

The beta-carotene content in milk and cheese is an accurate indicator for the feeding method used for cows. It can also be sued as an indicator of adulteration of goat and other types of milk with cow milk. A high accuracy HPLC-UV method for the determination of beta-carotene from milk and cheese has been developed. After saponification with an alcoholic solution of potassium hydroxide the samples where extracted with a mixture of hexane: ethyl acetate (70:30) was used. The concentrated extract was analyzed using Perkin Elmer 200 Series High Performance Liquid Chromatograph (HPLC) with UV detector for the determination of beta-carotene content. The calibration was done in 4 points from 1-20 ng/ml. The recovery yield was between 73,8-89,7 %. The method was tested on 3 milk samples and 5 cheese samples. The highest concentration of beta-carotene was found in cheddar cheese produced with milk from pasture raised cows.