173. The effect of commercial sterilization on the nutritive value of milk. III. Effect on the vitamin A and carotene content of milk

Abstract

1. The vitamin A and carotene content of raw milk have been compared with that of milk from the same bulk after it had been commercially sterilized. 2. For this purpose the fat was obtained by ether extraction from eleven samples of raw milk and from eleven corresponding samples of sterilized milk. As the sterilized milk had been previously homogenized it was not possible to churn it. 3. The vitamin A and carotene content was estimated by colorimetric (Lovibond tintometer) and by spectrophotometric tests. 3. The vitamin A and carotene content was estimated by colorimetric (Lovibond tintometer) and by spectrophotometric tests. 4. The results showed that the efiect of the heat treatment was negligible, neither method demonstrating a loss in vitamin A, while for carotene only the colorimetric method indicated a loss of about 2 %. 5. The vitamin A and carotene contents of sterilized milk were not decreased after storage for several weeks in a cool dark place.