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Valtcho D. Zheljazkov, Tess Astatkie, Barry O'Brocki, and Ekaterina Jeliazkova

Anise (Pimpinella anisum L.) is a spice, an essential oil crop, and a medicinal plant with a long history of use. Anise seed oil is extracted from anise seed through steam distillation. There is no experimentally established optimal time for distillation of anise seed. We hypothesized that the distillation time (DT) can be customized for optimum yield and composition of anise essential oil. In this study, we determined the effect of nine steam DTs (5, 15, 30, 60, 120, 180, 240, 360, and 480 minutes) on essential oil yield and essential oil composition of anise seed. We developed regression models to predict essential oil yield, the concentration of individual constituents, and the yield of these constituents as a function of DT. Highest essential oil yield (2.0 g/100 g seed, 2%) was obtained at 360-minute DT. The concentration of transanethole, the major anise oil constituent, varied from 93.5% to 96.2% (as a percent of the total oil) and generally was high at 15- to 60-minute DT and low at 240- to 480-minute DT. However, the yield of transanethole (calculated from the essential oil yield and the concentration of transanethole in the oil) increased with increasing DT to reach maximum at 360-minute DT. The concentration of the other oil constituents varied significantly depending on the DT, and some of them were higher at the shorter DT than at the longer DT. However, the yields of these constituents were highest at longer DT (either 360 or 480 minutes). DT can be used to obtain anise essential oil with different composition that would benefit the essential oil industry. This study demonstrated the need for providing DT in reports where anise seed essential oil yield and composition are discussed. This article can also be used as a reference point for comparing studies in which different DTs were used to extract essential oil from anise seed.

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Linda M. Falzari, Robert C. Menary, and Valerie A. Dragar

Fennel (Foeniculum vulgare Mill.) is grown commercially in Tasmania for the production of a steam-distilled essential oil, which is high in trans-anethole. Often, only the generative canopy is harvested since this contains the bulk of the oil and further this oil is higher in anethole than oil from other parts of the plant. Regardless of whether the whole crop is forage harvested or the generative canopy alone is removed using a combine-harvester, the most efficient oil production occurs when the greatest proportion of the canopy is generative, giving maximum oil yield from a minimum of fresh weight to be processed. A trial was conducted to examine the relationship between stand density and the various yield components of fennel in order to predict the likely effect on yield of increasing stem density as the short term perennial crop matures. As for most crops, planting density and biomass yield are closely related and the optimum planting density was predicted using a mathematical model. The results suggest that an initial stand density of 10 to 12 plants/m2, in a square layout, would produce the greatest yield of essential oil per unit area by maximising the production of the generative canopy. This density also maximises the yield of oil relative to the weight of material to be distilled.

Free access

Kelly M. Bowes and Valtcho D. Zheljazkov

Field and laboratory experiments were conducted at two sites in Nova Scotia during 2001 and 2002 to assess the potential to grow fennel (Foeniculum vulgare Mill.) as an essential oil crop in the Maritime region of Canada. Three cultivars—`Shumen', `Berfena', and `Sweet Fennel'—and two seeding dates—24 May and 8 June—were evaluated. Essential oil yields and composition were determined and compared to commercially available fennel essential oil from the U.S. The highest herbage yields were produced by `Shumen' from the earlier seeding date. Essential oil content and yields were lowest in `Sweet Fennel' and highest in `Shumen'. The major component of the essential oil was anethole, 47% to 80.2%. Other major components of the essential oil were methyl chavicol, fenchone, α-phellandrene, α-pinene, ortho cymene, β-phellandrene, fenchyl acetate, β-pinene, and apiole. The essential oil composition was unique to each cultivar. The highest methyl chavicol content was in `Shumen', while the highest concentration of phellandrene, fenchyl acetate and apiole were detected in `Sweet Fennel' oil. Fenchone, ortho cymene, β-pinene, α-phellandrene, and α-pinene were the highest in `Berfena'. The composition of the oil was similar to the commercially purchased oil and met industry requirements of oil composition. The results suggest there is potential to grow fennel as an essential oil crop in Nova Scotia.

Open access

Carol A. Miles, Thomas S. Collins, Yao Mu, and Travis Robert Alexander

-value crop. The high market value of bulb fennel is also supported by its significant health benefits. Its unique flavor is due to an anethole essential oil ( Kitajima et al., 1998 ). Transanethole is the most common compound of anethole found in bulb fennel