Manufacture of a low oxalate mitsumame-type dessert using rhubarb juice and calcium salts

Abstract

Rhubarb (Rheum rhabarbarum) juice was used to make a Japanese soft mitsumame-type dessert sweet. The dessert was prepared from extracted rhubarb juice, which was cooked with sugar, agar and guar gum, then allowed to set in sweet moulds. The total, soluble and insoluble oxalates were determined in the ingredients and the final products using HPLC chromatography. To reduce the soluble oxalate content of the dessert while retaining the colour and taste of the final product, increments of CaCl2 and CaCO3 were added to the test dessert mixes. The addition of CaCl2 reduced the pH from 3.55 ± 0.03 to pH 3.09 ± 0.02 while addition of CaCO3 increased the pH from 3.55 ± 0.03 to 4.96 ± 0.01. In both cases, the incremental addition of calcium reduced the soluble oxalate content of the sweets by converting it to insoluble oxalate.