Variation in retinol and carotenoid content of milk and milk products in The Netherlands

Abstract

Retinol and carotenoids were measured in Dutch milk and dairy products using a validated approach based on complete extraction of fat, followed by mild saponification and analysis by high-performance liquid chromatography. Raw milk, full fat milk, semi-skimmed milk and butter contain about 10 μg retinol and 6 g carotenoids per g fat. Values for retinol equivalents in milk are 10–20% higher than the values published in the Dutch food composition table. β-Carotene comprises 90% of total carotenoids present in cow's milk, contrary to values published for human milk, which show more equally distributed carotenoids. Winter milk contains 20% less retinol and β-carotene compared to summer milk. Retention of retinol and β-carotene per g fat in hard cheese is one third to one half relative to the corresponding raw milk. In liquid and semi-liquid dairy products (pasteurized milk, buttermilk, vanilla custard, and yoghurt) retention of both compounds is above 80%. Recovery of carotenoids using the validated method is better than that reported by others previously.