Extraction process 1: Extraction of Piperine from black pepper
Piperine
Piperine forms monoclinic crystals or prisms when recrystallized from alcohol. The crystals have a melting point of 130 Celsius. The crystals are at first tasteless, but then rapidly impart a burning taste when ingested. Piperine is insoluble in water, slightly soluble in alcohol, and soluble in chloroform, benzene, and acetic acid. Piperine is readily extracted from black pepper, and is one of the chief compounds responsible for the characteristic taste of black pepper.
Method 1: Extraction of piperine from black pepper
Materials:
1. 75 grams (2.6 oz.) of powdered or finely ground black pepper
4. 65 milliliters (2.2 fluid oz.) of warm water
2. 750 milliliters (25.3 fluid oz.) of 95% ethyl alcohol
5. 65 milliliters (2.2 fluid oz.) of more water
3. 50 milliliters (1.7 fluid oz.) of a 10% potassium hydroxide solution in 95% ethyl alcohol
6. 100 milliliters (3.4 fluid oz.) of acetone
Hazards: Wear gloves when handling potassium hydroxide, which is very corrosive. Extinguish all flames before using ethyl alcohol, and acetone, both of which are flammable.
Procedure: Into a standard reflux apparatus, place 75 grams (2.6 oz.) of powdered or finely ground black pepper (if using fresh black pepper corns or granules, the corns or granules should be finely ground before using). Note: 75 grams of black pepper is about 2/3 of a normal bottle sold in the grocery store. After adding the black pepper to the reflux apparatus, add in 750 milliliters (25.3 fluid oz.) of 95% ethyl alcohol. Thereafter, reflux the mixture at 78 Celsius for about 4 or 5 hours. After the reflux extraction process, remove the heat source, and allow the alcohol mixture to cool to room temperature. Thereafter, filter the alcohol extract to remove insoluble materials, and then place this filtered alcohol extract into a distillation apparatus, and distill-off the ethyl alcohol at 78 Celsius until the total remaining volume is about 75 milliliters (2.5 fluid oz.). When most of the ethyl alcohol has been removed, and the left over remaining alcohol concentrate is around 75 milliliters (2.5 fluid oz.) in volume, stop the distillation process, and collect the left over remaining alcohol concentrate (after it has cooled), and place it into a clean beaker. Then, into a second clean beaker, add in 50 milliliters (1.7 fluid oz.) of a 10% potassium hydroxide solution in 95% ethyl alcohol. Thereafter, to the potassium hydroxide/alcohol solution, add in the concentrated alcohol extract, and thereafter, heat the total mixture at about 60 to 70 Celsius. When the temperature of this mixture reaches 60 to 70 Celsius, slowly add drop wise, 65 milliliters (2.2 fluid oz.) of warm water. Note: during the addition of the water, the desired piperine compound will gradually precipitate. When precipitation begins, remove the heat source, and allow the alcohol mixture to cool to room temperature, and during this cooling period continue to add the water, slowly and drop-wise. When the mixture has cooled to room temperature, add in 65 milliliters (2.2 fluid oz.) of more water (cold water this time), and then stir the entire mixture for about 30 minutes at room temperature, and then allow the entire mixture to stand (no stirring) for several hours at room temperature. Afterwards, filter-off the precipitated solid, and then vacuum dry or air-dry it. Finally, recrystallize this dry solid from 100 milliliters (3.4 fluid oz.) of acetone, and after the recrystallization process, vacuum dry or air-dry the filtered-off crystals. The result will be about 3 grams (0.1 oz.) of the desired piperine compound with a melting point of 128 Celsius.
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Figure 010. Reflux apparatus equipped with drying tube for the extraction of piperine from black pepper. Cold water should be circulated through the reflux condenser jacket.
