Chemometric tools for identification of volatile aroma-active compounds in oregano

Abstract

One of the purposes of chemical analysis is to find quick and efficient methods to answer complex analytical questions in the life sciences. New analytical methods, in particular, produce a flood of data which are often very badly arranged. An effective way to overcome this problem is to apply chemometric methods. As part of the following investigations, three brands of oregano were analysed to identify their volatile aroma-active compounds. Two techniques were applied--gas chromatograpy-olfactometry (GC-O) and human sensory evaluation. Aroma-impact compounds could be identified in the main brands of oregano with the aid of chemometric methods (principal-components analysis, hierarchical cluster analysis, linear discriminant analysis, partial least-squares regression). Therefore, it is possible to reduce the analysis of sensory and olfactometry to relevant attributes. This makes classifying new species easier, much faster, and less expensive and is the premise for quick and more economic identification of new potential genotypes for oregano plant breeding. A comprehensive list of oregano key odourants, determined by GC-O and human sensory evaluation using different methods of supervised and unsupervised pattern cognition, has not previously been published.

Identification of aroma-active compounds in ‘wonderful’ pomegranate fruit using solvent-assisted flavour evaporation and headspace solid-phase micro-extraction methods

“…Aroma-active compounds were identified by the nasal impact frequency (NIF) method [14] as modified by Bansleben et al [15]. The GC-O analysis was conducted at Dr. D. Ulrich's laboratory in Quedlinburg, Germany, by seven olfactometry panellists, trained in GC sniffing and odour recognition [16][17][18][19].…”

The Use of Plant Growth Promoting Rhizobacteria (Pgpr)’s Effect on Essential Oil Rate, Essential Oil Content, Some Morphological Parameters and Nutrient Uptake of Turkish Oregano

“…Carvacrol, thymol, p-cymene, gamma-terpinene, borneol, linalool, and alpha-terpinene is main component of essential oil of O. onites (Bokov et al, 2015). Carvacrol is main component of essential oils of this species (Avcı and Bayram, 2013), which is an oxygenated monoterpene with multiple pharmacological actions (Baser, 2008), and an important impact compound of oregano aroma (Bansleben et al, 2009). It is also known for its antibacterial, antifungal, antioxidant, insecticidal, anti-angiogenic and anticarcinogenic activities, antispasmodic effects, lipid peroxidase inhibition, radical scavenging effect and cardiac depressant activity (Kotan et al, 2014).…”

Identification of aroma-active compounds in fresh and stored ‘Mor’ mandarins

“…Volatile aroma-active compounds in mandarin HS extracts were identified by the nasal impact frequency (NIF) method (Pollien et al, 1997) with some modifications (Wijaya et al,2005;Bansleben et al, 2009). GC-O analysis was carried out by seven olfactometry panellists, trained in GC sniffing and odour recognition, who sniffed the GC effluent.…”