# Discrimination of Aroma Characteristics for Cubeb Berries by Sensomics Approach with Chemometrics
## 1 Introduction  
_Ltisea cubeba_ (Lour.) Pers. (Lauraceae) gives off an aromatic odor and smells similar to an intensely lemonlike, spicy aroma. _Ltisea cubeba_ (_L. cubeba_) is a promising industrial crop as its fruit is rich in valuable essential oil. Recently, many reports have demonstrated the bioactivities of essential oil in _L. cubeba_[1; 2; 3; 4]. _L. cubeba_ has been widely employed in a flavoring or herbal medicinal industries and could be used as an ingredient in ionone flavors, botanical insecticides, food spices, and personal-care products. The dried berry of _Piper cubeba_ (Piperaceae), known as the 'cubeb pepper' or 'tailed pepper', have been widely used as a popular spice, with beneficial properties, including anti-inflammatory, analgesic, anti-proliferative, and leishmaniasisicidal activities [5; 6], and a flavoring agent for gins and cigarettes consumed throughout Europe as well as in many other Polynesian countries [7]. _L. cubeba_ has been described as the cubeb berry in the Chinese Pharmacopoeia, whereas _P. cubbeba_ has been also listed as the origin of cubeb berries. Both of the two cubeb berries have provided special flavors for daily life. It is well known that the flavor of food is tightly related to the stimulation of the human chemical senses, odor and taste; meanwhile, the odor is mainly caused by different volatile compositions [8]. Therefore, it is an appropriate method to discriminate the two ambiguous cubeb berries by the identification of volatiles. The volatile profiles of cubeb berries were studied previously using hydro-distillation (HD) for the extraction of essential oil. [PERSON] et al. [1] investigated the inhibitory activities of _L. cubeba_ essential oil and found the main chemical composition including limonene oxide, d-limonene. Hydro-distillation (HD) and simultaneous distillation/extraction (SDE) have been the common methods for the volatile extraction of different materials [9]. SDE united the advantages of liquid-liquid and steam distillation-extraction and has been widely recognized as a relative convenient extraction method for essential oils. However, distillation at elevated temperatures may lead to the loss of some compounds and generate artefacts due to thermal changes. Headspace solid-phase microextraction (HS-SPME) based on the distribution coefficient of analytes among the sample matrix, the gas phase, and the fiber coating was a simple, rapid, and solvent-free technique [10]. SDE and SPME methods have been widely used to extract the volatiles of potato products [11], milk products [12], tea [13], and meat products [14]. However, to the best of our knowledge, headspace volatiles of cubeb fruit, directly contacting human olfactory receptors and closely associated with an overall special spicy aroma, were still not analyzed until now. Rather than rate techniques (HD, SDE, and SPME) as more superior to another in performance, HD, SDE, and SPME could be regarded as the techniques that provide complementary information for each other [14]. In present study, we evaluated the volatile profiles of different cubeb berries by the use of three extraction methods (HD, SDE, and SPME) coupled to GC-MS and combined with the principal component analysis, which would provide more comprehensive data for the discrimination of ambiguous cubeb fruit. It is known that only a small portion of the large number of volatiles in a food matrix contribute to its overall perceived odor. GC-O is an appropriate analytical solution, as the eluted substances are perceived simultaneously by two detectors, one of them being the human olfactory system. Therefore, GC-O provides not only an instrumental, but also a sensorial analysis [8]. The GC-O technique has been widely used to the identification of aroma-active compounds from different fruits [15; 16; 17; 18]. However, so far, GC-O technique has not been applied to the identification of aroma-active compounds of cubeb fruit.