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Phosphorylation of L-ascorbate (0) with alkaline trimetaphosphate was investigated using calcium ion as catalyst. With initially 1.3 equivalents of sodium trimetaphosphate based on 0 at 1.42 M, and 0.36 equivalents of calcium ion based on phosphorus, the phosphorylation reaction was complete in 20 min at 20-25C and pH 9.5-10.0. The pH was maintained by periodic addition of calcium hydroxide so that the final ratio of Ca/P was 0.42. The extent of 2-phosphorylation at optimum conditions was 98% as determined by UV spectroscopy and liquid chromatograph under pressure with UV detection. Only 1% unreacted 0 and less than 0.3% of 4,5-ene by-products were detected in the reaction mixture. Barium and strontium ions also catalyzed the phosphorylation reaction, but not magnesium ion. L-ascorbate (or its free acid, AsA), L-ascorbate 2-monophosphate (AsMP), and L-ascorbate 2-polyphosphate (AsPP) were used to prevent warmed-over-flavor (WOF) in refrigerated cooked ground turkey, ground beef, and beef rump roast, and to fortify enriched white pan bread and two carbonated beverages (Pepsi Cola and Orange Slice). When added to ground turkey and ground beef at a level of 0.17% AsA equivalents based on meat "as is", AsMP and AsPP prevented development of WOF after cooking and storing the meat 3 days at 5C, as indicated by low levels of hexanal in the meat. On the other hand, AsA at a level of 0.1% was ineffective in ground turkey, but sodium ascorbate gave a small benefit in ground beef. A beef rump roast, after injecting with a solution of 0.18% sodium AsMP or AsPP (in AsA equivalents) and oven-roasting, developed practically no hexanal upon refrigeration for 5 days. Pepsi Cola and Orange Slice fortified with AsA, ASMP, and AsPP at a level of 30 mg AsA equivalents/250 mL lost 3-30% of AsA equivalents after storing 4-6 weeks at 15-35C if AsMP was added, compared to 35-40% for AsA. Surprisingly, ASPP was no more stable than AsA in the two beverages. Enriched white bread fortified with 400 mg AsA equivalents/100 g flour of AsPP, or 560 mg of AsMP, provided 56% and 97%, respectively, of the adult recommended dietary allowance in one slice of bread (28 g) after 4 days storage at 25C, compared to 40% for 560 mg AsA.
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