The amount of water co-extracted with carotenoids was determined as follows: the total weight of the tube with extract was recorded and the total extract weight was calculated. Anhydrous sodium sulphate was added to the extraction tube until the water in the extract was completely absorbed. Then, the oil extract was washed out into a pre-weighed vial with hexane and the weight of oil extract was determined. The weight of the water extract was calculated as the weight of the total extract minus the weight of the oil extract.