Essential oils spices investigation

It has been known for centuries that codistillation of many plant materials with steam produces a fragrant mixture of liquids called essential oils. For hundreds of years, such plant extracts have been used as medicines, spices, and perfumes. The investigation of essential oils also played a major role in the emergence of organic chemistry as a science during the 19th century. 

The antioxidant activity of rosemary and sage (leaves and extracts) were most effectively investigated [96,97], Traditional extracts of spices and herbs are obtained by steam distillation (essential oil) or by extracting the botanical with solvents such as alcohol, hexane, or acetone, and removing the solvents by evaporation. The SFE process for production of the inherent natural antioxidants is now the most gentle and effective method [70],... 

Essential oil from spice materials including cumin was investigated on sunflower oil, stored at 70°C and was found to possess excellent antioxidant effects, better than those of the synthetic antioxidant, butylated hydroxytoluene (Singh et al, 1998). 

Due to its unique characteristics and physicochemical properties such as being less toxic, nonflammable, and having the extraction power tuned by temperamre and pressure, SC CO2 can be used as a green solvent for extraction of substances especially from solid or liquid substrates. Such extraction has been carried out on commercial scale for more than two decades and applications like decaffeination of coffee beans and black tea leaves and hops extraction are involved in large-scale processes [17]. Other extractions such as extraction of flavors, spices, and essential oils from plant materials are under investigation. An overview of published data for different materials is given in the review of Marr and Gamse [18]. 

To investigate the potential of the SEME technique, comparisons have been made with hydrodistillation for extraction of essential oil from spices - ajowan Carum ajowan Apiaceae), cumin (Cuminum cyminum Umbdliferae), star anise Illicium anisatum Illiciaceae) - and from fresh aromatic herbs - basil ( Ocimum basilicum Labiaceae), crispate mint [Mentha crispa Labiaceae), thyme (Thymus vulgaris Labia-ceae) [59, 60]. The yields of essential oil and their chemical composition for the two extraction methods are reported in Table 22.4. 

Preparation of very small amounts of essential oils may be necessary if only very small amounts of plant material are available and can be fundamental in chemotaxonomic investigations and control analysis but also for medicinal and spice plant breeding. In the past, numerous attempts have been made to minimize conventional distillation devices. As an example, the modi ed Marcusson device may be quoted (Bicchi et al., 1983) by which 0.2 3 g plant material suspended in 50 mL water can be distilled and collected in 100 pL analytical grade pentane or hexane. The analytical results proved to be identical with those obtained by conventional distillation. 

A large number of monoterpenoids have been detected in or isolated from essential oils and solvent extracts of fungi, algae, liverworts, and higher plants, but the presence of monoterpenoids in fern is negligible. Vegetables, fruits, and spices contain monoterpenoids however, their fate in human and other animal bodies has not yet been fully investigated systematically. The recent development of analytical instruments makes it easy to analyze the chemical structures of very minor components, and the essential oil chemistry eld has dramatically developed. 

Investigation of the Essential Oils of Herbs and Spices—A Mini-Research Project... 

Stahl has published two papers on caraway extraction. In 1976 [49] he used S.CO2 followed by TLC and in 1982 [43] a more comprehensive investigation extracting at 90 bar and 20°C, followed by fractionation of the essential oil at 30 bar and 0°C. Yields reported for steam distillation were 4.1 %, CO2, hexane 14.1 %. Calame and Steiner used S.CO2 conditions of 200 bar and 40 C with methyl acetate entrainer. After fractionation at 55 bar and 37 C they obtained an oil at 1% yield but this only contained 38% volatile oil [13]. This equates to a 2.66% oil content from the CO2 extraction of the spice compared to 2.42% they found by steam distillation, so proving a quantitive extraction of volatile oil. 

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