Now Foods Vitamin C-1000. Kosher & Halal. Calcium Ascorbate is a buffered salt (mineral) form of the water-soluble antioxidant Vitamin C (ascorbic acid). Ascorbate (vitamin C) is a reducing sugar (has a reactive ene-diol structure) that is involved in biochemical processes such as hydroxylation of proline and lysine utilized in the formation of collagen and healthy connective tissue.