An average quality dry seed, on crushing and steam distillation, gives about 2-3% volatile oil. Anethole accounts for 80-90% of this, which gives the characteristic flavor. Star anise (Chapter 92) also has a high anethole content. The quantity of aniseed oil produced worldwide is only a fraction of the volatile oil from star anise. Other components from aniseed include a-pinene, camphene, linalool, anisaldehyde, ace- toanisole, and safrole. Studies with Bangladeshi varieties of aniseed showed some interesting minor constituents (Nahar et al., 2012).
Aniseed oil has a rich aromatic odor and flavor and can be considered to be slightly more pleasant than the oil of star anise. According to the FCC, anise oil occurs as a pale yellow liquid with the characteristic odor and taste of anise.
Physical characteristics as defined by the FCC are as follows:
Optical rotation -2 to +1°
Refractive index 1.553-1.560 at 20 °C Specific gravity 0.978-0.988
Solubility 1 mL dissolves in 3 mL of 90% alcohol