Process for producing a particulate composition comprising anhydrous crystalline 2-o-alpha-d-glucosyl-l-ascorbic acid

A process for producing a particulate composition comprising anhydrous crystalline 2-O-α-D-glucosyl-L-ascorbic acid, said process comprising the following steps (a) to (e):

• (a) allowing a cyclomaltodextrin glucanotransferase to act on a solution comprising either liquefied starch or dextrin and L-ascorbic acid as materials, and then allowing a glucoamylase to act on the resulting solution to obtain a solution comprising 2-O-α-D-glucosyl-L-ascorbic acid in a 2-O-α-D-glucosyl-L-ascorbic acid production yield of at least 27% by weight;
• (b) purifying the resulting solution comprising 2-O-α-D-glucosyl-L-ascorbic acid to give a 2-O-α-D-glucosyl-L-ascorbic acid content of over 86% by weight, on a dry solid basis;
• (c) precipitating anhydrous crystalline 2-O-α-D-glucosyl-L-ascorbic acid from the purified solution with a 2-O-α-D-glucosyl-L-ascorbic acid content of over 86% by weight, on a dry solid basis, by a controlled cooling method or pseudo-controlled cooling method;
• (d) collecting the precipitated anhydrous crystalline 2-O-α-D-glucosyl-L-ascorbic acid;
• and
• (e) ageing, drying, and optionally pulverizing the collected anhydrous crystalline 2-O-α-D-glucosyl-L-ascorbic acid without dissolving and recrystallizing it to obtain a particulate composition comprising anhydrous crystalline 2-O-α-D-glucosyl-L-ascorbic acid which comprises 2-O-α-D-glucosyl-L-ascorbic acid in a content of, on a dry solid basis, over 98.0% by weight but below 99.9% by weight, and has a degree of crystallinity for anhydrous crystalline 2-O-α-D-glucosyl-L-ascorbic acid of at least 90%, when calculated based on the powder X-ray diffraction profile of the particulate composition.