_applied sciences_  
_Article Essential Oil Variability of Azorean Cryptomeria japonica Leaves under Different Distillation Methods, Part 1: Color, Yield and Chemical Composition Analysis_  
[PERSON] 1,2,3, [PERSON] 2,3, [PERSON] 2,3, [PERSON] 2,3, [PERSON] 1,4,5, [PERSON] 5 and [PERSON] 1,4,*5  
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and the aromatic and aliphatic components, derived from phenylpropane. They can be composed of only a few to up to more than 100 components in different concentrations. Nevertheless, they are generally characterized by few major components being present at high concentrations compared with other components that are found at low or trace amounts. In general, the main components determine the characteristic odor and the functional and biological properties of the EOs. However, the overall bioactivity of botanical extracts can result from mixtures of components with synergistic, additive, or antagonistic effects. Thus, to investigate the viability of a specific EO application, knowledge about their total chemical composition is required [1; 3; 4]. Plant-derived EOs have been widely used all over the world since ancient times, and their production has increased tremendously over the last five decades due the strong demand for natural products, which are less hazardous to the public health and environment than their synthetic equivalents. In fact, numerous EOs, as natural products with GRAS (Generally Recognized as Safe) statuses, have commercial applications in many important industries such as food, beverage, fragrances, cosmetics, cosmecuticals, perfumery, household products, pharmaceutical, aromatherapy, phytomedicine, and agronomic (e.g., pesticides) industries [2; 3; 4; 5; 6]. However, as is well established, the yield (usually 1 to 3% of the plant weight) and chemical composition of EOs obtained from aromatic plants and, consequently, their functional bioactivity value, commercial uses, and price, depend on many factors, such as species, EO chemotypes, varieties or subspecies, plant organ, age and vegetative cycle stage, biotic interactions, spatial and temporal changes in environmental parameters (including light intensity, temperature, rainfall, relative humidity, and soil conditions), management practices (e.g., daily harvest period) and post-processing of plant material (e.g., drying), extraction protocols (e.g., method/apparatus used and extraction time), storage of EO, and analytical methods [1; 2; 7; 8; 9]. It should be noted that several reports have highlighted that the extraction method of EOs could lead to damage or alteration of their chemical profile with impacts on their quality [5; 9; 10]. Several processes can be used to isolate EOs from plants, such as the traditional distillation that is still used in many parts of the world in view of its simplicity and environmentally friendly practice due to the use of water compared with solvent extraction. Steam distillation (SD), water-steam distillation (WSD), and hydrodistillation (HD) using a Cleverger-type apparatus are among the most traditional and commonly used methods [5]. The SD method has been widely used, especially for industrial-scale production. In small-scale industries, WSD is an alternative method.