Sichuan pepper CO2 extract

Lemon, grapefruit, lavender-like floral, resin, light wood. Fresh and buzzing, with a numbing effect on the tongue in the total extract. Unlike black pepper: no heat, more citrus and floral.

Sichuan pepper CO2 extract has no dedicated standard in the IFRA 51 index. Linalool and limonene are present and are EU-labelled allergens above threshold.

The total extract contains hydroxy-α-sanshool, which causes a tingling, numbing sensation and can be felt on skin at high concentration. Store dark, sealed and cool.

Sichuan pepper is the dried fruit husk of Zanthoxylum species, in the citrus family. The black seeds inside are usually discarded; only the husk is used. Sichuan, especially Hanyuan county, is known for the red type. In Vietnam, mắc khén of the northwest belongs to the same genus; it is usually given as Zanthoxylum rhetsa, but its species identity is debated.

The numbing, tingling sensation comes from hydroxy-α-sanshool, an amide that activates sensory receptors. It is non-volatile and contributes no odour.

CO2 extraction uses compressed carbon dioxide as the solvent. Under subcritical conditions CO2 takes mainly the volatile fraction, giving a product called a select extract. Under supercritical conditions it also takes lipids and non-volatiles, giving a total extract. On depressurisation the CO2 evaporates completely and leaves no solvent residue.

The volatile fraction is rich in linalool and limonene, so the odour leans to citrus and flowers more than pepper. Ratios vary by species: red huajiao is warmer and woodier, green types (Z. armatum, Z. schinifolium) fresher and more lemony.

In perfumery Sichuan pepper CO2 serves citrus-spicy tops in woody, floral and tea accords. It pairs with grapefruit, yuzu, ginger, lavender and cedarwood.

The select extract is easier to use in perfume because it carries little of the numbing compound. The total extract is widely used in food.