Process for manufacturing a sweetener and use thereof
Highly purified Stevioside, Rebaudioside A and a purified sweet steviol glycoside mixture were prepared from sweet glycoside extracts obtained from Stevia rebaudiana Bertoni leaves. The resulting sweeteners are suitable as non-calorie, non-cariogenic, non-bitter, non-lingering sweeteners, which may be advantageously applied in foods, beverages, and milk products.
1. A process for producing a low-calorie sweetener composition, comprising:
a) providing a low intensity sweetener;
b) providing a crystallization inhibitor;
c) dissolving the sucrose and crystallization inhibitor in water to make a solution with 60% to 80% (w/w) total solids content;
d) purging the solution (c) with nitrogen to obtain a purged sugar solution;
e) providing a high intensity sweetener;
f) dissolving the high intensity sweetener in water to obtain a high intensity sweetener solution with about 10% to about 70% (w/w) solids;
g) adding the high intensity sweetener solution to the purged sugar solution to obtain a sweetener composition solution containing about 50% to about 80% (w/w) total solids;
h) evaporating the sweetener composition solution to obtain a concentrated sweetener composition solution with about 90% to about 97% (w/w) solids content;
i) feeding the concentrated sweetener composition solution to an impact beating apparatus to induce intensive crystallization and residual water evaporation, and to produce free flowing granules of the sweetener composition;
j) drying the granules to form the low-calorie sweetener composition.
2. The process of claim 1 , wherein the high intensity sweetener is made by a process comprising the steps of: i) drying Stevia rebaudiana leaves; ii) treating the dried Stevia rebaudiana leaves with water to extract sweet glycosides, wherein a leaves-water mixture is formed; iii) filtering the leaves-water mixture to obtain an aqueous filtrate; iv) directly treating the aqueous filtrate with calcium hydroxide or calcium oxide to raise the pH of the aqueous filtrate to about 10; v) directly neutralizing the treated aqueous filtrate with trivalent iron chloride; and vi) filtrating the neutralized aqueous filtrate to obtain a filtrated aqueous filtrate, and evaporating the filtrated aqueous filtrate to dryness to obtain purified sweet glycosides.
3. The process of claim 2 , further comprising: vii) dissolving the purified sweet glycosides of claim 2 in methanol at temperatures 20-50.degree. C. in an amount of 1:2-1:7 (w/v) to precipitate Stevioside from solution; viii) filtering the solution from step (i) to recover the precipitate of Stevioside; ix) suspending the precipitate of Stevioside obtained in step (ii) in an alcohol-water solution to further purify the Stevioside; and x) recovering a higher purity of Stevioside with a purity of at least 98%.
4. The process of claim 3 , which further comprises: combining remaining alcohol solutions; removing the alcohol; ultrafiltering to obtain a filtrate; and recovering Rebaudioside A with a purity of at least 98%.
5. The process of claim 1 , wherein in step (d) the solution is purged with nitrogen at a rate of about 1 to 10 liters per minute per liter of solution at a temperature ranging from about 50-80° C., for about 0.5-10 hours.
6. The process of claim 1 , wherein in step (h) evaporation is carried out with any equipment suitable for evaporating water from aqueous solution to obtain concentrated sweetener composition with about 90% to 97% (w/w) total solids.
7. The process of claim 6 wherein the evaporation is carried out at about 100-150° C., under about a 300-800 mbar vacuum, for about 0.5-2 minutes.
8. The process of claim 1 wherein step (i) the impact beating apparatus is a device capable of introducing shear mechanical impact or agitation to the concentrated sweetener composition solution.
9. The process of claim 8 wherein the mechanical impact duration on the concentrated sweetener composition solution is between about 0.01-300 seconds.
10. The process of claim 8 wherein the impact beating apparatus is provided with a water vapor removal system.
11. The process of claim 1 wherein step (j) the granules are dried by means of any apparatus suitable for drying powder.
12. The process of claim 11 wherein the drying is conducted at about 50-80° C.
13. The process of claim 1 further comprising sifting the obtained granular low calorie sweetener composition to obtain fractions with specific particle size.
14. The process of claim 13 wherein the particle size in the range of 0.5-2 mm.