A method for improving the stability of Vitamin D in liquid nutritional products which contain hydrolyzed protein or free amino acids as a nitrogen source. Vitamin C is added to a liquid nutritional product at a concentration exceeding 300 mg/l, such that the concentration of Vitamin C is at least 300 mg/l during the shelf-life of the liquid nutritional product. Preferably the addition of Vitamin C occurs after the completion of preliminary heat treating of the liquid nutritional product. Alternatively, the addition of Vitamin C occurs prior to the preliminary heat treating of the liquid nutritional product. Preferably, an emulsifier is added to the liquid nutritional product prior to preliminary heat treating, with the emulsifier being a diacetyltartaric acid ester of monoglycerides and diglycerides; and cystine is added following the completion of preliminary heat treating.
Disclosed are sterilized, aseptically packaged, liquid nutritional formulas, and corresponding methods of making the formulas, wherein the formulas comprise Vitamin D and extensively hydrolyzed protein having a degree of hydrolysis of at least about 20%, and wherein the packaged formula is prepared by (a) sterilizing a liquid nutritional formula containing Vitamin D and extensively hydrolyzed protein having a degree of hydrolysis of at least about 20%; (b) sterilizing a container; and then (c) aseptically packaging the sterilized liquid nutritional formula in the sterilized container. The packaged formulas exhibit improved Vitamin D stability.
