GB849787A - Vitamin a compositions - Google Patents

Abstract

A vitamin A composition comprises an ester of vitamin A uniformly dispersed throughout the reaction product of formaldehyde and partially hydrolysed casein. The acetate, tertiary butyl acetate, pivalate, anthraquinone-b -carboxylate and hemi-succinate, and palmitate esters may be used, the palmitate being preferred. About 5 to 25% by weight of vitamin A of antioxidants may be added, e.g. butylated hydroxy toluene, butylated hydroxy anisole, ascorbyl palmitate, a -tocopherol. About 5 to 15% of amines for example cyclohexylamine, N-ethyl-piperidine, dibutylamine may also be added. The partially hydrolysed casein may be prepared by the mild hydrolysis of casein with dilute mineral acid or proteolytic enzymes such as pepsin or trypsin and may have an a -amino nitrogen content of from less than 1% to 10% (preferably 0,5 to 7,0%). It is conveniently used as an aqueous suspension having a solids content of about 25 to 45% (preferably about 30 to 35%) in which the vitamin A ester and antioxidants are dispersed in amounts which will give a final product having about 10,000 to 500,000 international units of vitamin A activity per gram. Formaldehyde is added with stirring to this mixture preferably at or near room temperature, conveniently as the readily available 37% solution and stirring or mixing is continued for about 5 minutes to an hour (preferably about 15 minutes) during which time the product becomes semi-solid and some granulation may occur. The ratio by weight of formaldehyde to partial hydrolysate of casein may vary from about 1:10 to 1:100 and is preferably 1 part to from 10 to 15 parts of hydrolysate. The reaction mass may be granulated and dried at temperatures up to 100 DEG C. at atmospheric pressure or under vacuum to give a dry, free flowing powder which may be incorporated in animal feed supplements and pharmaceutical preparations.