Method for producing allulose crystals

Abstract

Allulose crystals are efficiently produced from an allulose syrup using seed crystals.

1 . A method for producing allulose crystals, wherein the method comprises:
 a) cooling and agitating a first admixture comprised of a first portion of allulose syrup and allulose seed crystals and initiating crystallization of allulose dissolved in the allulose syrup, thereby forming a first massecuite comprising allulose crystals and a first mother liquor containing residual dissolved allulose, the cooling and agitating being continued until a first preselected target yield of allulose crystals is achieved;   b) optionally, separating the first massecuite into a first portion and a second portion;   c) optionally, combining a second portion of allulose syrup with the second portion of the first massecuite to form a second admixture; and   d) optionally, cooling and agitating the second admixture and initiating crystallization of allulose dissolved in the second portion of allulose syrup, thereby forming a second massecuite comprising allulose crystals and a second mother liquor containing residual dissolved allulose, the cooling and agitating being continued until a second preselected target yield of allulose crystals is achieved.   
     
     
         2 . The method of  claim 1 , wherein at least steps a) and b) are performed. 
     
     
         3 . The method of  claim 1 , wherein at least steps a), b) and c) are performed. 
     
     
         4 . The method of  claim 1 , wherein at least steps a), b), c) and d) are performed. 
     
     
         5 . The method of  claim 1 , wherein the first admixture is obtained by combining the first portion of allulose syrup and dry allulose crystals. 
     
     
         6 . The method of  claim 1 , wherein the first admixture is obtained by combining with the first portion of allulose syrup and a heel comprised of allulose crystals and a mother liquor. 
     
     
         7 . The method of  claim 1 , wherein the first admixture and second admixture are agitated in steps a) and d), if step d) is performed, respectively using an agitator having a tip speed of 0.02 to 2 m/sec. 
     
     
         8 . The method of  claim 1 , wherein step a) additionally comprises, following initiation of crystallization of allulose dissolved in the allulose syrup, combining at least one additional portion of allulose syrup with the first admixture. 
     
     
         9 . The method of  claim 1 , wherein the cooling in step a) involves lowering the temperature of the first admixture from within an initial temperature range to within a second temperature range and holding the temperature of the first admixture within the second temperature range for a period of time. 
     
     
         10 . The method of  claim 1 , wherein steps a)-d) are performed and the cooling in step d) involves lowering the temperature of the second admixture from within an initial temperature range to within a second temperature range and holding the temperature of the second admixture within the second temperature range for a period of time. 
     
     
         11 . The method of  claim 1 , wherein the allulose syrup has a dry solids content of 70% to 95% by weight. 
     
     
         12 . The method of  claim 1 , wherein the allulose syrup has an allulose purity of at least 70%. 
     
     
         13 . The method of  claim 1 , comprising an additional step of separating allulose crystals from the first mother liquor in the first portion of the first massecuite. 
     
     
         14 . The method of  claim 13 , wherein the separating is carried out at least in part by one or more physical separation methods selected from the group consisting of centrifugation, filtration, decantation, membrane separation and combinations thereof. 
     
     
         15 . The method of  claim 13 , wherein allulose crystals separated from the first mother liquor are subjected to i) washing with at least one of water, an organic solvent, a blend of organic solvents, a blend of water and organic solvent(s) or an aqueous solution comprised of at least one carbohydrate; ii) drying; or a combination thereof. 
     
     
         16 . The method of  claim 1 , wherein steps b)-d) are performed and are repeated at least once. 
     
     
         17 . A method for producing allulose crystals, wherein the method comprises:
 a). passing a feed syrup/recycled massecuite admixture, comprised of i) a feed syrup, comprising water and dissolved allulose, and ii) a recycled massecuite comprising allulose crystals and a recycled massecuite mother liquor containing dissolved allulose, wherein the feed syrup/recycled massecuite admixture has been cooled to within a first crystallization temperature range, through a first stage crystallization zone, while agitating the feed syrup/recycled massecuite admixture, maintaining the feed syrup/recycled massecuite admixture within the first crystallization temperature range and initiating crystallization of allulose dissolved in the feed syrup and recycled massecuite mother liquor, thereby forming a first massecuite comprising allulose crystals and a first mother liquor containing residual dissolved allulose, and withdrawing the first massecuite which has achieved a first preselected target yield from the first stage crystallization zone;   b). optionally, cooling the first massecuite withdrawn from the first stage crystallization zone to within a second crystallization temperature range and transferring the first massecuite to a second stage crystallization zone;   c). optionally, passing the first massecuite through the second stage crystallization zone while agitating the first massecuite, maintaining the first massecuite within the second crystallization temperature range and initiating crystallization of allulose dissolved in the first mother liquor, thereby forming a second massecuite comprising allulose crystals and a second mother liquor containing residual dissolved allulose, and withdrawing the second massecuite which has achieved a second preselected target yield from the second stage crystallization zone; and   d). optionally, repeating steps b and c at least once to yield a final massecuite comprising allulose crystals and a final mother liquor.   
     
     
         18 . The method of  claim 17 , wherein at least steps a) and b) are performed. 
     
     
         19 . The method of  claim 17 , wherein at least steps a), b) and c) are performed. 
     
     
         20 . The method of  claim 17 , wherein at least steps a), b), c) and d) are performed. 
     
     
         21 . The method of  claim 17 , wherein steps a)-d) are performed and comprising an additional step of separating the allulose crystals in at least a portion of the final massecuite from the final mother liquor. 
     
     
         22 . The method of  claim 17 , wherein steps a)-d) are performed and wherein a portion of the final massecuite is used as the recycled massecuite. 
     
     
         23 . The method of  claim 17 , wherein the feed syrup/recycled massecuite admixture is obtained by mixing in a mixing vessel the feed syrup with the recycled massecuite comprised of allulose crystals and a recycled massecuite mother liquor containing dissolved allulose to provide the feed syrup/recycled massecuite admixture and transferring the feed syrup/recycled massecuite admixture from the mixing vessel into the first stage crystallization zone. 
     
     
         24 . The method of  claim 17 , wherein at least steps a)-c) are performed and the first admixture and second admixture are agitated in steps a) and c) respectively using an agitator having a tip speed of 0.02 to 2 m/sec. 
     
     
         25 . The method of  claim 17 , wherein the allulose syrup has a dry solids content of 70% to 95% by weight. 
     
     
         26 . The method of  claim 17 , wherein the allulose syrup has an allulose purity of at least 70%. 
     
     
         27 . The method of  claim 21 , wherein the separating is carried out at least in part by one or more physical separation methods selected from the group consisting of centrifugation, filtration, decantation, membrane separation and combinations thereof. 
     
     
         28 . The method of  claim 21 , wherein allulose crystals separated from the final mother liquor are subjected to i) washing with at least one of water, an organic solvent, a blend of organic solvents, a blend of water and organic solvent(s) or an aqueous solution comprised of at least one carbohydrate; ii) drying; or a combination thereof. 
     
     
         29 . The method of  claim 17 , wherein the feed syrup/recycled massecuite admixture is passed through the first stage crystallization zone in a plug flow manner and/or, if steps b) and c) are performed, the first massecuite is passed through the second stage crystallization zone in a plug flow manner. 
     
     
         30 . The method of  claim 1 , wherein the method is performed in a continuous manner. 
     
     
         31 . Allulose crystals, obtained in accordance with the method of  claim 1 . 
     
     
         32 . A consumable product, comprised of or prepared using allulose crystals in accordance with  claim 31  and at least one additional ingredient other than allulose crystals. 
     
     
         33 . A method of making a consumable product, comprising using allulose crystals in accordance with  claim 31 . 
     
     
         34 . A mother liquor, obtained in accordance with the method of  claim 1 . 
     
     
         35 . The mother liquor of  claim 34 , wherein the mother liquor is suitable for use as a product consumable by humans or animals or as an ingredient in a formulated product consumable by humans or animals.