Extraction method
1. Solvent extraction Solvent extraction method is the use of petroleum ether, ethanol, acetone and other single solvent or mixed solvent, the pepper skin grinding, room temperature stirring, leaching, filtration for several times. For example, with capsaicin as the raw material, 10% sodium hydroxide solution was used to extract, stirred at 60℃ for 5h, then stratified, the lower water was added with diluted hydrochloric acid to adjust the pH to 5, and the crude capsaicin compounds were extracted twice by petroleum ether and acetone, concentrated and crystallized, with the yield of 70.64% and the purity of 93.5% after recrystallization by ethyl ether.
2. Ultrasonic extraction Compared with traditional extraction, ultrasonic extraction has the advantages of high yield, short production cycle, no heating and no destruction of active ingredients. For example, under the conditions of 1:15 solid-liquid ratio,70% ethanol as the extraction solvent, extraction temperature 60℃, ultrasonic frequency 28kHz, power 120W, extraction time 20min, the yield of capsaicin was 2.819mg/g, the extraction rate was 64.2%, the extraction rate for three consecutive times reached 89.4%, nearly 20% higher than the traditional ethanol extraction method.
3. Microwave-assisted extraction: The capsaicin was extracted by microwave pretreatment with acetic acid. Each gram of capsaicin was soaked with 1ml 10% acetic acid as gasifier for 15min and pre-treated with microwave power of 480W after 90s.
4. Supercritical fluid extraction supercritical fluid extraction is a relatively new extraction separation technology, which effectively overcomes the shortcomings of traditional separation methods. It uses high pressure gas above critical temperature as a solvent to separate, extract and refine effective components. For example, supercritical extraction of capsaicin from Xinjiang capsaicin was performed under the conditions of extraction pressure of 12MPa, extraction temperature of 45 ° C, separation temperature of 45 ° C, extraction time of 40min, and the ratio of solid to liquid of anhydrous ethanol as the binder. The extraction rate of capsaicin reached 5.0mg/g, which was higher than the traditional solvent extraction method. Supercritical fluid extraction (SFE) is characterized by high extraction speed, low solvent and impurity content, but its high equipment cost is an important factor restricting its industrial production.
5. Enzymatic method At present, enzymatic extraction has been widely used in the extraction of plant active components, such as the extraction of safflower yellow pigment by enzymatic method, the extraction of flavonoids by enzymatic method. Because capsaicin and other fat-soluble components are present in the uneven fibrous tissue of the skin of capsaicin, enzymatic hydrolysis of the fibrous tissue can dissolve the capsaicin. For example, the capsaicin in dry red capsaicin was extracted with cellulase. The extraction conditions were as follows: the enzymatic hydrolysis temperature was 55℃, the initial pH of the enzymatic hydrolysate was 5.4, the enzymatic hydrolysis time was 4h, and the enzyme amount was 2.5mg/g capsaicin. The yield of natural capsaicin was 7.65mg/g capsaicin, which increased by 33% compared with the traditional ethanol extraction method.