Milk is an almost complete single food containing significant amounts of essential nutrients; its whey is a good source of water-soluble vitamins, while its lipid fraction is an important delivery medium of fat-soluble vitamins, especially vitamin A. Vitamin A-active compounds occur in milk mainly as retinoids and to a lesser extent as carotenoid precursors (provitamins A). Very little is known about the quali-quantitative profile of retinoids in bovine milk as well as in that of other ruminant species. Only one study, describes the HPLC-UV analysis of retinyl esters in cow, goat and human milk. The main analytical difficulties are related to the unavailability of standards, their cost and the complexity in development chromatographic separation; in fact, vitamin A vitamers are characterized by subtle differences in chemical structures so a highly efficient and selective chromatographic system is needed for achieving their resolution. A reliable analytical approach, based on high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS), allowed us to establish the real occurrence and distribution of several retinoids in raw cow, sheep, goat and water buffalo milk samples. Direct liquid extraction with solvents was performed for isolating retinoids while alkaline hydrolysis enabled the total retinol determination; yields exceeding 68% were obtained for all analytes. Chromatographic separation was carried out using two tandem systems of reversed-phase columns (C18/C18 and C18/C30) in order to achieve total separation of the vitamin A vitamers. The chromatograph was coupled on-line with a triple quadrupole mass spectrometer, and the MS detection was accomplished by means of positive atmospheric pressure chemical ionization (APCI), operating in the Selected Reaction Monitoring (SRM) mode. According to our results, and in the light of the FAO/WHO recommendations, the consumption of milk may supply a significant portion of the daily intake of vitamin A, proving to be an important food, especially for infants and children. Buffalo milk, in particular, has a high level of retinyl linolenate, that represents an additional nutritional value, since omega-3 fatty acids are essential for the proper functioning of the organism.
Retinoids in Raw Milk from Different Animal Species: a Complete Analytical Strategy Based on LC-MS/MS Hyphenation / Caretti, Fulvia; Gentili, Alessandra; Curini, Roberta; G., D’Ascenzo; Marchese, Stefano; S., Rocchi. - STAMPA. - (2011), p. 153. (Intervento presentato al convegno XXIV Congresso Nazionale della Società Chimica Italiana tenutosi a Lecce nel 11-16 Settembre 2011).
Retinoids in Raw Milk from Different Animal Species: a Complete Analytical Strategy Based on LC-MS/MS Hyphenation
CARETTI, Fulvia;GENTILI, Alessandra;CURINI, Roberta;MARCHESE, Stefano;
2011
Abstract
Milk is an almost complete single food containing significant amounts of essential nutrients; its whey is a good source of water-soluble vitamins, while its lipid fraction is an important delivery medium of fat-soluble vitamins, especially vitamin A. Vitamin A-active compounds occur in milk mainly as retinoids and to a lesser extent as carotenoid precursors (provitamins A). Very little is known about the quali-quantitative profile of retinoids in bovine milk as well as in that of other ruminant species. Only one study, describes the HPLC-UV analysis of retinyl esters in cow, goat and human milk. The main analytical difficulties are related to the unavailability of standards, their cost and the complexity in development chromatographic separation; in fact, vitamin A vitamers are characterized by subtle differences in chemical structures so a highly efficient and selective chromatographic system is needed for achieving their resolution. A reliable analytical approach, based on high performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS), allowed us to establish the real occurrence and distribution of several retinoids in raw cow, sheep, goat and water buffalo milk samples. Direct liquid extraction with solvents was performed for isolating retinoids while alkaline hydrolysis enabled the total retinol determination; yields exceeding 68% were obtained for all analytes. Chromatographic separation was carried out using two tandem systems of reversed-phase columns (C18/C18 and C18/C30) in order to achieve total separation of the vitamin A vitamers. The chromatograph was coupled on-line with a triple quadrupole mass spectrometer, and the MS detection was accomplished by means of positive atmospheric pressure chemical ionization (APCI), operating in the Selected Reaction Monitoring (SRM) mode. According to our results, and in the light of the FAO/WHO recommendations, the consumption of milk may supply a significant portion of the daily intake of vitamin A, proving to be an important food, especially for infants and children. Buffalo milk, in particular, has a high level of retinyl linolenate, that represents an additional nutritional value, since omega-3 fatty acids are essential for the proper functioning of the organism.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
