Limonin extraction method

Abstract

A limonin extraction method, comprising the following steps: step one, raw material extracting or juicing: directly soaking raw material in water or using a presser to directly juice the raw material to obtain the extract; step two, adding salt and adjusting pH: adding a sulfate solid material or saturated sulfate solution to the extract; adjusting pH to 3-7; step three, heating and preserving heat: heating to 20 C.-100 C. and keeping at the temperature for 10 minutes-110 minutes; step four, centrifuging: centrifuging for 10 minutes at a rotational speed of 2500g, and obtaining limonin precipitation. Compared with a traditional method, the raw material in the present invention can directly use the extract liquid or juicing liquid without drying, and recover most limonin in water using a precipitation method without complicated apparatus, and is easy to operate and has a low process cost.

Claims

1. A limonin extraction method, comprising the following steps: step one, raw material extracting or juicing: directly soaking raw material in water or using a presser to directly juice the raw material to obtain an extract; step two, adding salt and adjusting pH: adding a sulfate solid material to the extract; and adjusting pH to 3-7; step three, heating and preserving heat: heating to 20 to 100 C. and keeping at the temperature for 10 minutes to 110 minutes; and step four, centrifuging: obtaining limonin precipitation by centrifugation at a rotational speed of 2500g for 10 minutes.

2. A limonin extraction method according to claim 1, wherein, in the step two, the sulfate is ammonium sulfate, magnesium sulfate, sodium sulfate or potassium sulfate.

3. A limonin extraction method according to claim 1, wherein, in the step two, the pH is adjusted to 4-6.

4. A limonin extraction method according to claim 1, wherein, in the step three, the heating temperature is 60-80 C.

5. A limonin extraction method according to claim 1, wherein, in the step three, the heating time is 10 minutes.

Description

DESCRIPTION OF THE EMBODIMENTS

(1) The embodiments of the present disclosure illustrate the process of the present disclosure with limonin extraction from pummelos. However, the present disclosure is not only limited to limonin extraction from pummelos and other citrus fruits, but also applicable to extraction from plant materials rich in limonin, such as neem, African mahogany, etc. Therefore, the method in the embodiments of the present disclosure is a general method for extracting limonin from plants containing limonin.

(2) The present disclosure detects the limonin content using Waters e2695 high performance liquid chromatograph (Waters e2695 Separations Module, Waters 2489 UV/Visible Detector, Empower 2 software) and Symmetry reversed phase C18 column (3.0250 mm, 5.0 m) under specific chromatographic detection conditions of: (1) detecting limonin at a wavelength of =210 nm; (2) flow rate: 0.5 ml/minute, column temperature: 35 C., sample injection volume: 20 L; (3) gradient elution conditions (A: ultrapure water, B: acetonitrile): 0-4 min 95% A; 4-14 min 95-60% A; 14-16 min 60% A; 16-4 min 60-30% A; 24-28 min 30-95% A; 28-32 min 95% A. Qualitative analysis is based on retention time, and quantitative analysis is based on peak area. Limonin extraction yield is calculated as per the following equation:
Limonin extraction yield (%)=A2/A1*100

(3) wherein:

(4) A1 indicates total content of limonin in pummelo extract (g/mL), and

(5) A2 indicates content of limonin in precipitation collected after centrifugation (g/mL).

(6) Embodiment 1

(7) Step one, pressing pummelo to obtain an extract. Limonin content in the extract was detected to be 84.21 g/mL;

(8) Step two, preparing 80% saturated ammonium sulfate solution. 1 mL of 80% saturated ammonium sulfate solution was fully mixed with 4 mL of the pummelo extract to obtain a pummelo extract with sulfate ion concentration of 0.85 mol/L and at a pH of 4.17;

(9) Step three, keeping at 50 C. for 90 minutes, and then heating at 100 C. for 20 minutes; and

(10) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(11) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 6.29 g/mL. The total extraction yield of limonin was calculated to be 7.47%.

(12) Embodiment 2

(13) Step one, pressing pummelo to obtain an extract. Limonin content in the extract was detected to be 85.87 g/mL;

(14) Step two, preparing 100% saturated ammonium sulfate solution. 1 mL of 100% saturated ammonium sulfate solution was fully mixed with 4 mL of the pummelo extract to obtain a pummelo extract with sulfate ion concentration of 1.07 mol/L and at a pH of 4.14;

(15) Step three, keeping at 50 C. for 90 minutes, and then heating at 100 C. for 20 minutes; and

(16) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(17) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 22.92 g/mL. The total extraction yield of limonin was calculated to be 26.69%.

(18) According to Embodiment 1 and Embodiment 2, the extraction yield of limonin is proportional to the concentration of ammonium sulfate in juice.

(19) Embodiment 3

(20) Step one, directly soaking pummelo in tap water to obtain an extract. Limonin content in the pummelo extract adjusted with sodium hydrogen phosphate to a pH of 4 was detected to be 60.11 g/mL;

(21) Step two, preparing 100% saturated ammonium sulfate solution. 1 mL of 100% saturated ammonium sulfate solution was fully mixed with 4 mL of the pummelo extract to obtain a pummelo extract with sulfate ion concentration of 1.07 mol/L and at a pH of 3.98;

(22) Step three, heating at 100 C. for 20 minutes; and

(23) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(24) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 17.25 g/mL. The extraction yield of limonin was calculated to be 28.70%.

(25) Embodiment 4

(26) Step one, directly soaking pummelo in tap water to obtain an extract. Limonin content in the pummelo extract adjusted with sodium hydrogen phosphate to a pH of 6 was detected to be 60.11 g/mL;

(27) Step two, preparing 100% saturated ammonium sulfate solution. 1 mL of 100% saturated ammonium sulfate solution was fully mixed with 4 mL of the pummelo extract to obtain a pummelo extract with sulfate ion concentration of 1.07 mol/L and at a pH of 5.97;

(28) Step three, heating at 100 C. for 20 minutes; and

(29) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(30) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 38.89 g/mL. The extraction yield of limonin was calculated to be 26.49%.

(31) Embodiment 5

(32) Step one, pressing pummelo to obtain an extract. Limonin content in the extract was detected to be 87.44 g/mL;

(33) Step two, preparing 100% saturated ammonium sulfate solution. 1 mL of 100% saturated ammonium sulfate solution was fully mixed with 4 mL of the pummelo extract to obtain a pummelo extract with sulfate ion concentration of 1.07 mol/L and at a pH of 4.14;

(34) Step three, heating at 100 C. for 20 minutes; and

(35) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(36) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 36.37 g/mL. The extraction yield of limonin was calculated to be 41.60%.

(37) Embodiment 6

(38) Step one, pressing pummelo to obtain an extract. Limonin content in the extract was detected to be 91.07 g/mL;

(39) Step two, preparing 100% saturated ammonium sulfate solution. 1 mL of 100% saturated ammonium sulfate solution was fully mixed with 4 mL of the pummelo extract to obtain a pummelo extract with sulfate ion concentration of 1.07 mol/L and at a pH of 4.15;

(40) Step three, heating at 100 C. for 30 minutes; and

(41) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(42) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 39.06 g/mL. The extraction yield of limonin was calculated to be 42.90%.

(43) Embodiment 7

(44) Step one, pressing pummelo to obtain an extract. Limonin content in the extract was detected to be 57.28 g/mL;

(45) Step two, preparing 100% saturated ammonium sulfate solution. 1 mL of 100% saturated ammonium sulfate solution was fully mixed with 4 mL of the pummelo extract to obtain a pummelo extract with sulfate ion concentration of 1.07 mol/L and at a pH of 4.14;

(46) Step three, heating at 60 C. for 15 minutes; and

(47) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(48) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 36.48 g/mL. The extraction yield of limonin was calculated to be 63.68%.

(49) Embodiment 8

(50) Step one, pressing pummelo to obtain an extract. Limonin content in the extract was detected to be 80.11 g/mL;

(51) Step two, adding ammonium sulfate solid to 4 mL of the pummelo extract to obtain a pummelo extract with ammonium sulfate concentration of 5.35 mol/L and at a pH of 3.99;

(52) Step three, heating at 70 C. for 20 minutes; and

(53) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(54) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 57.82 g/mL. The extraction yield of limonin was calculated to be 72.18%.

(55) Embodiment 9

(56) Step one, pressing pummelo to obtain an extract. Limonin content in the extract was detected to be 80.50 g/mL;

(57) Step two, adding ammonium sulfate solid to 4 mL of the pummelo extract to obtain a pummelo extract with ammonium sulfate concentration of 5.35 mol/L and at a pH of 3.13;

(58) Step three, heating at 80 C. for 20 minutes; and

(59) Step four, centrifuging at a rotational speed of 2500g for 10 minutes.

(60) The limonin content in the precipitation redissolved in 4 mL of 60% acetonitrile was detected to be 55.50 g/mL. The extraction yield of limonin was calculated to be 68.94%.

(61) Compared with a traditional method, the above methods of the present disclosure can directly use the extract or juice of the raw material without drying, and recover most limonin in water using a precipitation method without complicated devices, is easy to operate, and has low process cost.

(62) The above description only provides preferred embodiments of the present disclosure, and is not intended to limit the scope of embodiments of the present disclosure. That is, all equivalent variations and modifications made within the scope of the present disclosure and the contents of the Description shall fall within the scope of the present disclosure.