| 摘要 |
Disclosed is a process for the production of d-tagatose from deproteinized whey or whey permeate containing lactose after acid hydrolysis to provide a hydrolysate comprising 1 equivalent of d-glucose and 1 equivalent of d-galactose for each unit of lactose converted. More particularly, the invention relates to a process for the isomerization of d-galactose to d-tagatose and the use of a simplified separation scheme based on simulated moving bed (SMB) separation. The isomerization of d-galactose to d-tagatose is carried out in the presence of calcium oxide or calcium hydroxide. The process is useful for providing a simplified processing route to providing pure d-tagatose and glucose syrup as two products from lactose hydrolysate isomerate. D-tagatose is useful as a food additive, as a sweetener, as a texturizer, as a stabilizer, or as a humectant. |
| 主权项 |
1. A process for the production of high purity d-tagatose and high purity d-glucose from a condensed deproteinized whey stream, said process comprising:
a. passing the condensed deproteinized whey stream to a hydrolysis zone and therein admixing the condensed deproteinized whey stream with a dilute sulfuric acid stream to provide a dilute deproteinized whey stream and therein hydrolyzing at effective hydrolysis conditions at least a portion of the deproteinized whey stream in the presence of an effective amount of sulfuric acid to provide a hydrolysate stream comprising d-galactose, d-glucose, unconverted lactose, water, sulfuric acid and salts; b. passing the hydrolysate stream to a first neutralization zone and therein contacting the hydrolysate stream with an effective amount of calcium hydroxide to provide an unfiltered neutralized hydrolysate stream comprising d-galactose, d-glucose, unconverted lactose, water and salts; c. passing the unfiltered neutralized hydrolysate stream comprising d-galactose, d-glucose, unconverted lactose, water and salts to an isomerization zone at an effective isomerization temperature in the presence of an effective amount of calcium oxide and calcium chloride to isomerize at least a portion of the d-galactose to d-tagatose and d-glucose to provide an isomerate stream comprising d-galactose, d-glucose, lactose, d-tagatose, water, and salts; d. passing the isomerate stream to a second neutralization zone and therein contacting the isomerate stream with an effective amount of sulfuric acid to neutralize the isomerate stream and provide a neutralized isomerate stream having a pH of between about 6 and about 7; e. passing the neutralized isomerate stream to a filtration zone having a filter size effective to remove at least a portion of the salts to provide a filtered isomerate stream essentially free of salts comprising d-galactose, d-glucose, lactose, d-tagatose, and water; f. passing the filtered isomerate stream and a mobile phase desorption stream comprising water continuously to a continuous simulated moving bed (SMB) zone containing a plurality of adsorbent beds comprising a stationary phase agent consisting of a strong acid cation exchange resin having a calcium cation to continuously provide an extract stream comprising substantially pure d-tagatose, water, and a minor portion of d-galactose, a primary raffinate stream comprising water, d-galactose, and d-glucose, and a secondary raffinate stream consisting essentially of water; g. passing the extract stream to a first evaporization zone to remove at least a portion of the water to provide an evaporated extract stream; h. passing the evaporated extract stream to a crystallizer zone to provide a high purity d-tagatose stream in the form of a powder or crystals; i. passing the primary raffinate stream to a second evaporator to provide an enriched d-glucose syrup; and j. returning at least a portion of the secondary raffinate to step (f) to provide at least a portion of the mobile phase desorbent stream. |
