How to make capsaicin crystals. The method for extracting capsaicin crystals from chili extract in the present invention involves the following steps:

1. Extraction with Beta-Cyclodextrin Alkaline Solution:

   • Mix the crude chili extract with a beta-cyclodextrin alkaline solution in a weight ratio of 1:5 to 1:8.
   • Place this mixture into a single-stage continuous countercurrent ultrasonic extractor.
   • Subject the mixture to ultrasonic irradiation and countercurrent extraction for 10 to 60 minutes.
   • After extraction, filter the solution to separate the filtrate from the filter residue.
   • Repeat the ultrasonic countercurrent extraction 2 to 3 times using the filter residue, then filter again and combine all filtrates.
   • The beta-cyclodextrin alkaline solution comprises:
     • 5 to 8% sodium chloride aqueous solution,
     • 2 to 4% sodium acetate aqueous solution,
     • 0.5 to 2% sodium hydroxide aqueous solution,
     • 0.01 to 0.02% beta-cyclodextrin aqueous solution.

2. Concentration of Filtrate:

   • Concentrate the filtrate from Step (1) to a volume that is 1/20 to 1/10 of the original filtrate.

3. Ethanol Precipitation:

   • Mix the concentrated solution from Step (2) with 50-65% ethanol in a volume ratio of 1:5 to 1:12.
   • Allow the mixture to stand for 0.5 to 2 hours, then perform suction filtration at 40°C to 55°C.
   • Separate the filtrate from the filter residue, repeating the filtration process 2 to 3 times and combining all filtrates.

4. Ethanol Recovery and Crystallization:

   • Under vacuum at 0.1mPa and a temperature of 40°C to 55°C, concentrate the filtrate from Step (3) by evaporating the ethanol.
   • Perform low-temperature crystallization of the aqueous phase at 2°C to 8°C.
5. Isolation of Capsaicin Crystals:
   • Dissolve the crystals obtained from Step (4) in Sherwood oil.
   • Perform low-temperature crystallization at -10°C to -5°C to isolate the capsaicin crystals.

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Key Details:

• Cyclodextrin

  : Beta-cyclodextrin has a cylindrical structure with narrow ends and wide open centers, allowing it to form inclusion complexes with lipophilic compounds like capsaicin. This increases the stability of the guest molecule under light, heat, and oxidative conditions.

• Micro-cutting Process for Chili Extract

  : The chili extract is prepared using a micro-cutting process to enhance the cell-wall disruption of the chili powder. This increases the exposure of capsaicin and its release, improving solubility and extraction efficiency.
• Beta-Cyclodextrin-Alkaline Solution: The solution used in Step (1) ensures efficient extraction of capsaicin under specific conditions, and the proportions of sodium chloride, sodium acetate, sodium hydroxide, and beta-cyclodextrin are optimized for best results.

Advantages of the Invention:

1. Efficiency

   : The method uses beta-cyclodextrin and ultrasonic countercurrent extraction to reduce the extraction time and minimize solvent usage.
2. Improved Capsaicin Solubility: The use of micro-cutting technology improves the solubility of capsaicin in ethanol, further enhancing the extraction rate.

3. High Purity

   : The method produces capsaicin crystals with purity exceeding 98%, due to the controlled and optimized extraction and crystallization conditions.

Embodiment 1: Preparation of Chili Extract

1. Red Chili Powder:
   • Use Fructus Capsicis (e.g., commercial dried red chili).
   • Clean, remove impurities, dry to ≤8% moisture.
   • Pulverize and pass through a 60-mesh sieve to obtain red chili powder.
2. Grinding:
   • Mix 9.2 kg red chili powder with 0.8 kg beta-cyclodextrin.
   • Grind for 10 minutes in a planetary or vibration mill to form a fine powder.

3. Extraction

   :
   • Combine 10 kg of fine powder with 80 L of 65% ethanol.
   • Stir for 25 minutes, then let stand.
   • Use a supercentrifuge (10,000 rpm) to separate the precipitate and filtrate.
   • Extract the precipitate 3 more times using ethanol and centrifuge. Combine all filtrates.

4. Concentration

   :
   • Concentrate the filtrate under reduced pressure (0.1 mPa) at 55°C.
   • Reclaim ethanol and obtain the chili extract as a thick, garnet-colored liquid.

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Embodiment 2: Preparation of Chili Extract

1. Red Chili Powder:
   • Use Sichuan cluster red pepper.
   • Clean, dry (≤8% moisture), pulverize, and sieve through 80-mesh to obtain red chili powder.
2. Grinding:
   • Mix 9.8 kg red chili powder with 0.2 kg beta-cyclodextrin.
   • Grind for 30 minutes in a planetary or vibration mill.
3. Extraction:
   • Mix 10 kg fine powder with 150 L of 50% ethanol.
   • Stir for 10 minutes and let stand.
   • Use a supercentrifuge (8,000 rpm) to separate the precipitate and filtrate.
   • Repeat extraction of precipitate twice with ethanol, centrifuge, and combine all filtrates.

4. Concentration

   :
   • Concentrate filtrate under reduced pressure (0.1 mPa) at 45°C.
   • Reclaim ethanol to obtain the crude chili extract.

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Embodiment 3: Preparation of Chili Extract

1. Red Chili Powder:
   • Use Fructus Capsicis.
   • Clean, dry (≤8% moisture), pulverize, and sieve through a 100-mesh sieve to get chili powder.

2. Grinding

   :
   • Mix 9.5 kg chili powder with 0.5 kg beta-cyclodextrin.
   • Grind for 20 minutes in a planetary or vibration mill.

3. Extraction

   :
   • Combine 10 kg fine powder with 120 L of 60% ethanol.
   • Stir for 20 minutes, then let stand.
   • Centrifuge (12,000 rpm) to separate precipitate and filtrate.
   • Repeat extraction of precipitate 3 times, combine all filtrates.
4. Concentration:
   • Concentrate filtrate under reduced pressure (0.1 mPa) at 50°C.
   • Reclaim ethanol to obtain crude chili extract.

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Preparation of Beta-Cyclodextrin Alkaline Solution

Embodiment 4:

1. Dissolve 0.25 kg sodium chloride in 5 kg water to make a 5% solution.
2. Dissolve 0.15 kg sodium acetate in 5 kg water to make a 3% solution.
3. Dissolve 0.1 kg sodium hydroxide in 5 kg water to make a 2% solution.
4. Dissolve 0.002 kg beta-cyclodextrin in 20 kg water to make a 0.01% solution.
5. Mix 1 kg of the 5% sodium chloride solution, 4 kg of the 3% sodium acetate solution, 1 kg of the 2% sodium hydroxide solution, and 10 kg of the 0.01% beta-cyclodextrin solution to form the alkaline solution.

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Embodiment 5:

Similar to Embodiment 4 but with different concentrations (8% sodium chloride, 2% sodium acetate, 0.5% sodium hydroxide, and 0.02% beta-cyclodextrin).

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Embodiment 6:

Similar to Embodiment 4 but with different concentrations (6.5% sodium chloride, 4% sodium acetate, 1% sodium hydroxide, and 0.015% beta-cyclodextrin).

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Preparation of Capsaicin Crystals

Embodiment 7:

1. Mix 1 kg of Embodiment 1 chili extract with 5 kg of Embodiment 4 beta-cyclodextrin alkaline solution.
2. Extract using an ultrasonic extractor (30 kHz, 300 W, 25°C) for 20 minutes.
3. Filter the extract and combine the filtrate.
4. Concentrate the filtrate to 1/10 of its original volume.
5. Mix 1 L of the concentrated solution with 12 L of 60% ethanol and allow to stand for 1 hour.
6. Filter the solution at 55°C, combine the filtrate, and concentrate under reduced pressure (0.1 mPa) at 55°C.
7. Crystallize the aqueous phase at 2°C, then dissolve with Sherwood oil.
8. Crystallize again at -5°C to obtain needle-like capsaicin crystals.

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Embodiment 8:

1. Mix 1 kg of the chili extract crude product from Embodiment 2 with 8 kg of the beta-cyclodextrin alkaline solution from Embodiment 5 in a single-stage continuous countercurrent ultrasonic extractor. Set the extractor to 80 kHz frequency, 300 W power, and maintain a temperature of 10°C. Perform countercurrent extraction for 45 minutes to obtain the extracting solution.
2. Filter the extracting solution to separate the filtrate from the filter residue. Repeat the ultrasonic extraction of the filter residue twice, filtering after each cycle, and combine all the filtrate.
3. Concentrate the combined filtrate to reduce its volume to 1/20 of the original.
4. Mix 2 L of the concentrated solution with 20 L of 55% ethanol. Let the mixture stand for 0.5 hours, then perform suction filtration at 40°C. Separate the filtrate from the filter residue. Repeat suction filtration on the filter residue two more times, merging all filtrates.
5. Evaporate the filtrate under reduced pressure at 40°C and 0.1 mPa vacuum to reclaim the ethanol. The resulting aqueous phase is subjected to low-temperature crystallization at 4°C.
6. Dissolve the separated crystals in Sherwood oil, then perform low-temperature crystallization again at -8°C to obtain needle-like capsaicin crystals (1.16 g).
7. Measure the capsaicin purity using high-performance liquid chromatography (HPLC); the capsaicin crystals are found to contain 98.5% total alkaloids.

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Embodiment 9:

1. Combine 1 kg of the chili extract crude product from Embodiment 3 with 6.5 kg of the beta-cyclodextrin alkaline solution from Embodiment 6 in a single-stage continuous countercurrent ultrasonic extractor. Set the frequency to 20 kHz, the power to 500 W, and the temperature to 30°C. Perform countercurrent extraction for 30 minutes to obtain the extracting solution.
2. Filter the extracting solution to separate the filtrate from the filter residue. Repeat the ultrasonic extraction of the filter residue three times, filtering after each cycle, and combine all the filtrate.
3. Concentrate the combined filtrate to reduce its volume to 1/15 of the original.
4. Mix 1.5 L of the concentrated solution with 7.5 L of 65% ethanol. Let the mixture stand for 1.5 hours, then perform suction filtration at 45°C. Separate the filtrate from the filter residue. Repeat suction filtration on the filter residue two more times, merging all the filtrates.
5. Evaporate the filtrate under reduced pressure at 45°C and 0.1 mPa vacuum to reclaim the ethanol. The resulting aqueous phase undergoes low-temperature crystallization at 5°C.
6. Dissolve the separated crystals in Sherwood oil, then perform low-temperature crystallization again at -10°C to obtain needle-like capsaicin crystals (1.20 g).
7. Measure the capsaicin purity using HPLC; the capsaicin crystals are found to contain 99.0% total alkaloids.

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Embodiment 10:

1. Mix 1 kg of the chili extract crude product from Embodiment 1 with 5 kg of the beta-cyclodextrin alkaline solution from Embodiment 5 in a single-stage continuous countercurrent ultrasonic extractor. Set the frequency to 40 kHz, the power to 350 W, and the temperature to 60°C. Perform countercurrent extraction for 15 minutes to obtain the extracting solution.
2. Filter the extracting solution to separate the filtrate from the filter residue. Repeat the ultrasonic extraction of the filter residue three times, filtering after each cycle, and combine all the filtrate.
3. Concentrate the combined filtrate to reduce its volume to 1/10 of the original.
4. Mix 1 L of the concentrated solution with 12 L of 50% ethanol. Let the mixture stand for 1 hour, then perform suction filtration at 45°C. Separate the filtrate from the filter residue. Repeat suction filtration on the filter residue three more times, merging all the filtrates.
5. Evaporate the filtrate under reduced pressure at 55°C and 0.1 mPa vacuum to reclaim the ethanol. The resulting aqueous phase undergoes low-temperature crystallization at 8°C.
6. Dissolve the separated crystals in Sherwood oil, then perform low-temperature crystallization again at -8°C to obtain needle-like capsaicin crystals (1.15 g).
7. Measure the capsaicin purity using HPLC; the capsaicin crystals are found to contain 98.2% total alkaloids.

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Embodiment 11:

1. Combine 1 kg of the chili extract crude product from Embodiment 2 with 8 kg of the beta-cyclodextrin alkaline solution from Embodiment 6 in a single-stage continuous countercurrent ultrasonic extractor. Set the frequency to 50 kHz, the power to 400 W, and the temperature to 25°C. Perform countercurrent extraction for 60 minutes to obtain the extracting solution.
2. Filter the extracting solution to separate the filtrate from the filter residue. Repeat the ultrasonic extraction of the filter residue twice, filtering after each cycle, and combine all the filtrate.
3. Concentrate the combined filtrate to reduce its volume to 1/15 of the original.
4. Mix 1.5 L of the concentrated solution with 9 L of 60% ethanol. Let the mixture stand for 1 hour, then perform suction filtration at 50°C. Separate the filtrate from the filter residue. Repeat suction filtration on the filter residue two more times, merging all the filtrates.
5. Evaporate the filtrate under reduced pressure at 50°C and 0.1 mPa vacuum to reclaim the ethanol. The resulting aqueous phase undergoes low-temperature crystallization at 4°C.
6. Dissolve the separated crystals in Sherwood oil, then perform low-temperature crystallization again at -5°C to obtain needle-like capsaicin crystals (1.17 g).
7. Measure the capsaicin purity using HPLC; the capsaicin crystals are found to contain 98.5% total alkaloids.

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Embodiment 12:

Measure the capsaicin purity using HPLC; the capsaicin crystals are found to contain 98.7% total alkaloids.

Mix 1 kg of the chili extract crude product from Embodiment 3 with 6 kg of the beta-cyclodextrin alkaline solution from Embodiment 4 in a single-stage continuous countercurrent ultrasonic extractor. Set the frequency to 45 kHz, the power to 400 W, and the temperature to 45°C. Perform countercurrent extraction for 35 minutes to obtain the extracting solution.

Filter the extracting solution to separate the filtrate from the filter residue. Repeat the ultrasonic extraction of the filter residue three times, filtering after each cycle, and combine all the filtrate.

Concentrate the combined filtrate to reduce its volume to 1/20 of the original.

Mix 2 L of the concentrated solution with 20 L of 55% ethanol. Let the mixture stand for 0.5 hours, then perform suction filtration at 45°C. Separate the filtrate from the filter residue. Repeat suction filtration on the filter residue twice more, merging all the filtrates.

Evaporate the filtrate under reduced pressure at 55°C and 0.1 mPa vacuum to reclaim the ethanol. The resulting aqueous phase undergoes low-temperature crystallization at 2°C.

Dissolve the separated crystals in Sherwood oil, then perform low-temperature crystallization again at -8°C to obtain needle-like capsaicin crystals (1.18 g).

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General Notes for All Embodiments:

• Purity: The final capsaicin crystals typically show high purity (98.2%–99.0% alkaloid content) when measured by HPLC.
• Crystallization: Use Sherwood oil to dissolve and purify the crystals in cold temperatures (-5°C to -10°C).

Capsaicinoids

Wiki says, Capsaicin consist of capsaicinoids are capsaicin (69%), dihydrocapsaicin (22%), nordihydrocapsaicin (7%), homocapsaicin (1%), and homodihydrocapsaicin (1%). Capsaicin and dihydrocapsaicin (both 16.0 million SHU) are the most pungent capsaicinoids. Nordihydrocapsaicin (9.1 million SHU), homocapsaicin and homodihydrocapsaicin (both 8.6 million SHU) are about half as hot. There are six natural capsaicinoids (table below). Although vanillylamide of n-nonanoic acid (Nonivamide, VNA, also PAVA) is produced synthetically for most applications, it does occur naturally in Capsicum species.

Capsaicinoid name	Abbrev.	Typical relative amount	Scoville heat units
Capsaicin	CPS	69%	16Mil
Dihydrocapsaicin	DHC	22%	16Mil
Homocapsaicin	HC	17%	8.6Mil
Homodihydrocapsaicin	HDHC	1%
Nordihydrocapsaicin	NCP	1%	9.1Mil
Nonivamide	PAVA	1%	9Mil

Capsaicinoid Scoville Heat Chart