| 摘要 |
A process for the manufacture of alkali metal and alkaline earth metal salts of L-ascorbic acid 2-monophosphate comprises reacting a L--ascorbic acid 2-polyphosphate under alkaline conditions with an alkali metal or alkaline earth metal salt of L-ascorbic acid in concentrated aqueous solution, the amounts of the L-ascorbic acid salt and the alkaline earth met al hydroxide used as the base being arranged such that pH value of the reaction medium is held in the range of about 8 to about 11 and a stepwise transfer o f in each case one phosphate group from the polyphosphate to the L-ascorbic acid salt takes place until essentially the polyphosphate has been consumed and only L-ascorbic acid 2-monophosphate salt is present. Preferably, the L--ascorbic acid 2-polyphosphate is produced in situ and calcium hydroxide i s used as the base. Independently of whether the L-ascorbic acid 2--polyphosphate is produced separately or in situ, sodium trimetaphosphate is preferably used as the phosphorylating agent. A further aspect of the present invention comprises spray drying the mixture obtained after completion of the reaction, cooling and dilution to a suitable viscosity. Th e product of the process according to the invention is suitable as an additive for human and animal foodstuffs; it is especiallystable against oxidative and thermal degradation and has an especially high content of L-ascorbic acid monophosphate vis-à-vis polyphosphates and is accordingly primarily of use preferably for the nutritional enrichment of fish feed. |
