Method for preparing lycopene crystals with high purity and low harm

Abstract

The present invention relates to a method for preparing lycopene crystals with high purity and low harm. The method comprises the following steps: (1) mixing lycopene oleoresin with a mixed solvent consisting of an alkane and a lower alcohol, and heating and stirring the resultant for dissolution to form a homogenous solution; (2) cooling the homogenous solution for crystallization, filtering the resultant to obtain a filter cake; and (3) washing the filter cake successively using a lower alcohol and an alkane, and drying the resultant to obtain lycopene crystals. According to the method provided by the present invention, lycopene crystals can be obtained using a mixed solvent by means of one step crystallization, and the crystal content is further improved and harmful substances in the crystals are reduced by means of a two-step crystal washing process to obtain lycopene crystals with high purity and low harm. The method is fast and convenient, lycopene crystals with high purity, low harm, and sanitary safety can be produced, and the method is suitable for industrial production.

Claims

1. A method for preparing lycopene crystals with high-purity and low harm, comprising the following steps: (1) mixing lycopene oleoresin with a mixed solvent consisting of an alkane and a lower alcohol, heating the resultant for dissolution to form a homogenous solution; (2) cooling the homogenous solution for crystallization, filtering the resultant to obtain a filter cake; and (3) washing the filter cake successively using a lower alcohol and an alkane, and drying the resultant to obtain lycopene crystals.

2. The method according to claim 1, wherein the alkane in step (1) is one or more selected from n-hexane, cyclohexane, and No. 6 solvent-extracted oil; and/or, the lower alcohol is one or more selected from methanol, ethanol and isopropanol.

3. The method according to claim 1, wherein the volume ratio of alkane to lower alcohol in the mixed solvent is 2:1 to 4:1.

4. The method according to claim 1, wherein in step (1), the mass-to-volume ratio of the lycopene oleoresin to the mixed solvent is 4:1 to 8:1.

5. The method according to claim 1, wherein the temperature for heating dissolution in step (1) is 35° C. to 60° C.

6. The method according to claim 1, wherein the temperature for cooling crystallization in step (2) is 15° C. to 25° C.

7. The method according to claim 1, wherein the lower alcohol in step (3) is an aqueous solution with a volume fraction of 75% to 95% of a lower alcohol having not more than four carbon atoms; and/or, the temperature of alkane is 15° C. to 25° C.; the alkane is one or more selected from n-hexane, cyclohexane, and No. 6 solvent-extracted oil.

8. The method according to claim 1, wherein the drying is performed under vacuum at 30° C. to 60° C.

9. The method according to claim 1, wherein the entire process of steps (1) to (3) is performed in a fully closed “four-in-one” device for dissolving, crystallization, washing and drying.

10. The method according to claim 1, wherein the lycopene oleoresin is prepared by a method including the steps of: fully extracting dehydrated dried tomato peel in a combined solvent composed of alkane(s) and ketone(s), and recovering the solvent to obtain the lycopene oleoresin.

11. The method according to claim 2, wherein the volume ratio of alkane to lower alcohol in the mixed solvent is 2:1 to 4:1.

12. The method according to claim 2, wherein in step (1), the mass-to-volume ratio of the lycopene oleoresin to the mixed solvent is 4:1 to 8:1.

13. The method according to claim 3, wherein in step (1), the mass-to-volume ratio of the lycopene oleoresin to the mixed solvent is 4:1 to 8:1.

14. The method according to claim 2, wherein the temperature for heating dissolution in step (1) is 35° C. to 60° C.

15. The method according to claim 3, wherein the temperature for heating dissolution in step (1) is 35° C. to 60° C.

16. The method according to claim 4, wherein the temperature for heating dissolution in step (1) is 35° C. to 60° C.

17. The method according to claim 2, wherein the temperature for cooling crystallization in step (2) is 15° C. to 25° C.

18. The method according to claim 3, wherein the temperature for cooling crystallization in step (2) is 15° C. to 25° C.

19. The method according to claim 4, wherein the temperature for cooling crystallization in step (2) is 15° C. to 25° C.

20. The method according to claim 5, wherein the temperature for cooling crystallization in step (2) is 15° C. to 25° C.

21. The method according to claim 2, wherein the lower alcohol in step (3) is an aqueous solution with a volume fraction of 75% to 95% of a lower alcohol having not more than four carbon atoms; and/or, the temperature of alkane is 15° C. to 25° C.; the alkane is one or more selected from n-hexane, cyclohexane, and No. 6 solvent-extracted oil.

22. The method according to claim 3, wherein the lower alcohol in step (3) is an aqueous solution with a volume fraction of 75% to 95% of a lower alcohol having not more than four carbon atoms; and/or, the temperature of alkane is 15° C. to 25° C.; the alkane is one or more selected from n-hexane, cyclohexane, and No. 6 extraction solvent solvent-extracted oil.

23. The method according to claim 4, wherein the lower alcohol in step (3) is an aqueous solution with a volume fraction of 75% to 95% of a lower alcohol having not more than four carbon atoms; and/or, the temperature of alkane is 15° C. to 25° C.; the alkane is one or more selected from n-hexane, cyclohexane, and No. 6 solvent-extracted oil.

24. The method according to claim 5, wherein the lower alcohol in step (3) is an aqueous solution with a volume fraction of 75% to 95% of a lower alcohol having not more than four carbon atoms; and/or, the temperature of alkane is 15° C. to 25° C.; the alkane is one or more selected from n-hexane, cyclohexane, and No. 6 solvent-extracted oil.

25. The method according to claim 6, wherein the lower alcohol in step (3) is an aqueous solution with a volume fraction of 75% to 95% of a lower alcohol having not more than four carbon atoms; and/or, the temperature of alkane is 15° C. to 25° C.; the alkane is one or more selected from n-hexane, cyclohexane, and No. 6 solvent-extracted oil.

26. The method according to claim 2, wherein the drying is performed under vacuum at 30° C. to 60° C.

27. The method according to claim 3, wherein the drying is performed under vacuum at 30° C. to 60° C.

28. The method according to claim 4, wherein the drying is performed under vacuum at 30° C. to 60° C.

29. The method according to claim 5, wherein the drying is performed under vacuum at 30° C. to 60° C.

30. The method according to claim 6, wherein the drying is performed under vacuum at 30° C. to 60° C.

31. The method according to claim 7, wherein the drying is performed under vacuum at 30° C. to 60° C.

32. The method according to claim 10, wherein the volume ratio of the alkane(s) to ketone(s) in the combined solvent is 2:1 to 5:1; and/or, the extraction temperature is 35° C. to 60° C.

Description

SPECIFIC MODES FOR CARRYING OUT THE EMBODIMENTS

(1) The specific embodiments of the present invention will be further described in detail in combination with figures and Examples. The following Examples are intended to illustrate the present invention, but not intended to limit to the scope of the present invention.

(2) In the following examples, the lycopene oleoresin could be prepared by the following method:

(3) A: 15 tons of tomato peel residue with a moisture content of 90% was squeezed and dehydrated by screw press equipment, and cylinder dried to obtain dried tomato peel residue;

(4) B: The peel in the dried tomato peel residue was separated from seeds; the obtained dried tomato peel was processed into particles with a diameter of 7 mm and a length of 2 cm, and the separated tomato seeds were used to extract tomato seed oil.

(5) C: The tomato particles obtained in step B were extracted using a combined solvent with a ratio of n-hexane to acetone of 5:1 at a temperature of 60° C. for 120 minutes. After concentrating under reduced pressure to recover the solvent, lycopene oleoresin was obtained.

EXAMPLE 1

(6) The present Example provides a method for preparing lycopene crystals with high-purity and low harm, specifically comprising the following steps:

(7) (1) the lycopene oleoresin was mixed with a combined solvent with a ratio of 3:1 of n-hexane to methanol at a ratio of oleoresin to solvent of 4:1 in a “four-in-one” device at a temperature of 35° C., and dissolved for 15 min to obtain a homogenous solution;

(8) (2) the homogenous solution obtained from dissolving in step (1) was cooled to 15° C. and crystallized for 6 hours; after the crystallization was completed, filtration was performed directly in the device to obtain a filter cake of lycopene crystals;

(9) (3) the filter cake was washed with 80% ethanol aqueous solution at a volume of 2 times the wet weight of the filter cake to increase the content of crystals; then the filter cake was washed with n-hexane at a volume of 3 times the wet weight of the filter cake at 15° C. to further increase the content of crystals and remove benzopyrene and other harmful substances. The washed filter cake was dried under vacuum at 40° C. for 10 hours to obtain lycopene crystals.

(10) The purity of the lycopene crystals obtained by the present method was 85%, and the content of benzopyrene in the crystals was <10 ppm.

EXAMPLE 2

(11) The present Example provides a method for preparing lycopene crystals with high-purity and low harm, specifically comprising the following steps:

(12) (1) the lycopene oleoresin was mixed with a combined solvent with a ratio of 2:1 of n-hexane and methanol at a ratio of oleoresin to solvent of 6:1 in a “four-in-one” device at a temperature of 55° C., and dissolved for 30 min to obtain a homogenous solution;

(13) (2) the homogenous solution obtained from dissolving was cooled to 20° C. and crystallized for 8 hours; after the crystallization was completed, filtration was performed directly in the device to obtain a filter cake of lycopene crystals;

(14) (3) the filter cake was washed with 75% ethanol aqueous solution at a volume of 4 times the wet weight of the filter cake to increase the content of crystals; then the filter cake was washed with cyclohexane at a volume of 6 times the wet weight of the filter cake at 20° C. to further increase the content of crystals and remove benzopyrene and other harmful substances. The washed filter cake was dried under vacuum at 30° C. for 8 hours to obtain lycopene crystals.

(15) The purity of the lycopene crystals obtained by the present method was 90%, and the content of benzopyrene in the crystals was <10 ppm.

EXAMPLE 3

(16) The present Example provides a method for preparing lycopene crystals with high-purity and low harm, specifically comprising the following steps:

(17) (1) the lycopene oleoresin was mixed with a combined solvent with a ratio of 4:1 of n-hexane and methanol at a ratio of oleoresin to solvent of 8:1in a “four-in-one” device at a temperature of 60° C., and dissolved for 40 min to obtain a homogenous solution;

(18) (2) the homogenous solution obtained from dissolving was cooled to 25° C. and crystallized for 6 hours; after the crystallization was completed, filtration was performed directly in the device to obtain a filter cake of lycopene crystals;

(19) (3) the filter cake was washed with 95% ethanol aqueous solution at a volume of 5 times the wet weight of the filter cake to increase the content of crystals, then the filter cake was washed with No. 6 extraction solvent oil at a volume of 8 times the wet weight of the filter cake at 25° C. to further increase the content of crystals and remove benzopyrene and other harmful substances. The washed filter cake was dried under vacuum at 60° C. for 10 hours to obtain lycopene

(20) The purity of the lycopene crystals obtained by the present method was 93.7%, and the content of benzopyrene in the crystals was <10 ppm.

Comparative Example 1

(21) Compared with Example 3, the difference only lies in that the combined solvent composed of n-hexane and methanol was replaced with petroleum ether.

(22) After testing, the purity of the lycopene crystals obtained by the method of the present Comparative Example was 55%, and the content of benzopyrene in the crystals was 200 ppm.

(23) The above contents are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement and the like made according to the spirit and principle of the present invention should be regarded as within the protection scope of the invention.