Process for obtaining useful materials from Fenugreek seeds

• US 6,495,175 B2
• Filed: 02/09/2001
• Issued: 12/17/2002
• Est. Priority Date: 02/14/2000
• Status: Expired due to Fees

• Current Assignee: Angappa M. Ponraj, Garrimella B. Rao, Thavitturpalayan K. Rajendran
• Original Assignee: Angappa M. Ponraj, Garrimella B. Rao, Thavitturpalayan K. Rajendran
• Inventors: Rajendran, Thavitturpalayan K., Ponraj, Angappa M., Rao, Garrimella B.
• Primary Examiner(s): TATE, CHRISTOPHER ROBIN
• Application Number:
  US09/780,947
• Publication Number:
  US 20010024665A1
• Time in Patent Office: 676 Days
• Field of Search: 424/725, 424/757, 424/776
• US Class Current: 424/757
• CPC Class Codes: A23L 27/11 obtained by solvent extraction
• CPC Class Codes: A23L 33/22 Comminuted fibrous parts of plants, e.g. bagasse or pulp
• CPC Class Codes: C11B 1/10 by extracting

Abstract

A method for obtaining substantially pure fixed oil(s), oleoresin and dietary fiber from Fenugreek seeds is provided. The method employs two different solvent extraction stages, wherein the first extraction isolates fixed oils and the second extraction isolates oleoresin. The dietary fiber remaining after extraction is clean, approximately light yellow to light brown, substantially tasteless and substantially odorless. An extraction system (23) for conducting the extractions is also provided. The extraction system (23) includes a condenser (24), a seed holding extraction vessel (25), a reboiler ((26), solvent and extract reservoir) and a feedback loop (28). The extraction solvent is obtained from the reboiler and it is contacted with the Fenugreek seeds while hot shortly after condensation in the condenser. The extraction system employs minimal amounts of solvent compared to conventional processes. In terms of color, taste, and/or odor, the food grade isolated fixed oils, oleoresin and dietary fiber are superior to those products obtained from conventional extraction processes.

Claims

1. A method of obtaining valuable components from Fenugreek seeds comprising the steps of:

extracting the Fenugreek seeds with a hot first extraction solvent to provide a first useful extract and a first extracted mass, wherein the first useful extract comprises fixed oils;

extracting the first extracted mass with a hot different second extraction solvent to provide a second useful extract and a second extracted mass, wherein the second useful extract comprises oleoresin; and

removing solvent from the second extracted mass to provide a useful solid;

wherein

the first extraction solvent is selected from the group consisting of petroleum ether, hexane, n-propanol, isopropanol, and a combination thereof; and

the second extraction solvent is selected from the group consisting of ethanol, isopropanol, aqueous isopropanol, aqueous ethanol and a combination thereof; and

the process further comprises the step of;

removing a major portion of the first extraction solvent from the first useful extracts to form substantially pure fixed oil.

2. The method of claim 1 further comprising the step of:

removing a major portion of the second extraction solvent from the second useful extract to form a first mixture comprising oleoresin and fixed oil.

3. The method of claim 2 further comprising the step of:

treating the first mixture of oleoresin and fixed oil with an ethanolic solution to form a fluid comprising a first layer comprising a major portion of oleoresin and second layer comprising a second mixture of ethanol, fixed oil and optionally one or more other components; and

separating the first layer from the second layer to produce a substantially pure oleoresin.

4. The method of claim 3 further comprising the step of:

removing solids, if any, from the second mixture; and

removing at least a major portion of the ethanol from the second mixture to form substantially pure fixed oil.

5. The method of claim 1, wherein the useful solid comprises a dietary fiber.

6. The method of claim 1 further comprising one or more of the following steps:

cleaning the seeds;

grinding the seeds;

sorting the seeds;

tempering the seeds;

flaking the seeds;

crushing the seeds;

or

milling the seeds.

7. The method of claim 1, wherein the first extraction solvent is petroleum ether having a boiling range of about 40-60°

C. and the second extraction solvent is an ethanolic solution.

8. The method of claim 1, wherein the first and second solvents are hot and recently condensed prior to addition.

9. The method of claim 8, wherein the first extraction solvent is obtained from a reservoir containing the first useful extract and the second extraction solvent is obtained from a reservoir containing the second useful extract.

10. The method of claim 8, wherein the first and second extraction solvents are solute free.

11. The method of claim 1, wherein the first extraction step removes at least 85% of the fixed oils from the seeds.

12. A process for the extraction of fenugreek seeds to produce substantially pure dietary fiber, oleoresin and fixed oils comprising the steps of:

(i) optionally sorting and cleaning the Fenugreek seeds and optionally crushing, grinding flaking and/or milling the seeds;

(ii) extracting the seeds with a substantially freshly condensed first extraction solvent in a first stage of extraction to yield a first extract and partly extracted seeds;

(iii) extracting the partly extracted seeds with substantially freshly condensed second extraction solvent in a second stage of extraction to yield a second extract and a wet dietary fiber;

(iv) drying the wet dietary fiber to form a substantially pure dietary fiber;

(v) heating the first extract to remove at least a major portion of the first extraction solvent therein to yield substantially pure fixed oils;

(vi) heating the second extract to remove at least a major portion of the second extraction solvent to yield a first mixture comprising oleoresin and substantially the remainder of the fixed oils in the seeds;

(vii) treating the first mixture with an ethanolic solution for a period of time and at a predetermined temperature to form a treated mixture;

(viii) cooling the treated mixture to a lower temperature to yield a fluid comprising at least a heavy phase and a light phase;

(ix) separating the heavy phase from the light phase, to form a substantially pure oleoresin;

(x) separating any solids from the light phase; and

(xi) evaporating the ethanolic solution from the light phase to yield substantially pure fixed oils;

wherein

the first solvent is selected from the group consisting of petroleum ether, hexane, n-propanol and isopropanol and mixtures thereof; and

the second solvent is selected from the group consisting of ethanol, isopropanol, aqueous isopropanol, aqueous ethanol and mixtures thereof.

13. The process of claim 12, wherein the seeds are substantially continuously extracted with substantially freshly condensed solvent over substantially the whole the contact time.

14. The process of claim 12, wherein the first solvent is petroleum ether having a boiling range of about 40-60°

C., and the second solvent is at least 90% aqueous ethanol.

15. The process of claim 14, wherein the first extraction is conducted at a temperature of 50°

C. to 60 °

C. and the second extraction is conducted at a temperature of 78°

C. to 82°

C.

16. The process of claim 12, wherein the seed is sized to −

60 to +90 BSS.

17. The process of claim 12, wherein the ratio of the amount of the seed to the amount of first extraction solvent is 1:

1 to 1;

5 weight/volume (kg/L), and the ratio of the amount of the seed to the amount of second extraction solvent is 1;

1 to 1;

7 weight/volume (kg/L).

18. The process of claim 17, wherein the overall contact time in the first extraction is about 1 to 2.5 hours and in the second extraction is about 2 to 4 hours.

19. The process of claim 18, wherein the cycle times in the first and second extractions range from 15 minutes to 35 minutes.

20. The process of claim 12, wherein the first mixture is treated with at least 95% ethanol for a period of time about 45 minutes to 90 minutes at a temperature of about 45°

C. to 55°

C.

21. The process of claim 20, wherein the ratio of amount of the first mixture to the at least 95% ethanol is about 1:

1 to 1;

3.

22. The process of claim 12, wherein the treated mixture is cooled to about −

10°

C. to −

15°

C.