title: Online gas chromatography combustion/pyrolysis-isotope ratio mass spectrometry (HRGC-C/P-IRMS) of (+/-)-Dihydroactinidiolide from tea ( Camellia sinensis ) and rooibos tea ( Aspalathus linearis ).
abstract: Online capillary gas chromatography-isotope ratio mass spectrometry in both the combustion and the pyrolysis modes (HRGC-C/P-IRMS) was employed to perform authentication studies of the flavoring agent (+/-)-dihydroactinidiolide. Thus, the delta(13)C(V-PDB) and delta(2)H(V-SMOW) values of synthetic (ex synthetic beta-ionone and natural beta-carotene) as well as enzymatically (ex synthetic and natural beta-carotene) produced references were studied in comparison with those of the natural substance isolated from black (n = 17) and green teas (n = 6) ( Camellia sinensis ) as well as Rooibos tea ( Aspalathus linearis ) (n = 7). The isotope values determined for both the synthetic and enzymatically produced samples of (+/-)-dihydroactinidiolide reflected the influence of the origin of their educts. Hence, in cases when synthetic educts were used, the delta(13)C(V-PDB) and delta(2)H(V-SMOW) values ranged from -27.0 to -28.4 per thousand and from -28 to -169 per thousand, respectively, whereas the use of natural educts led to ranges from -30.3 to -31.6 per thousand and from -154 to -228 per thousand, respectively. As to the tea samples, delta(13)C(V-PDB) and delta(2)H(V-SMOW) values ranging from -29.0 to -34.1 per thousand and from -153 to -274 per thousand, respectively, were recorded for (+/-)-dihydroactinidiolide from black and green teas, whereas that from Rooibos tea showed (2)H/(1)H ratios ranging from -189 to -210 per thousand as well as slightly enriched values in the (13)C/(12)C ratios ranging from -24.4 to -27.1 per thousand.
authors.affiliation: Lehrstuhl für Lebensmittelchemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany.
authors.forename: María
authors.initials: M
authors.lastname: del Mar Caja
authors.forename: Christina
authors.initials: C
authors.lastname: Preston
authors.forename: Michael
authors.initials: M
authors.lastname: Menzel
authors.forename: Michael
authors.initials: M
authors.lastname: Kempf
authors.forename: Peter
authors.initials: P
authors.lastname: Schreier
mesh_terms: D036903:Aspalathus / Q000737:chemistry*; D001572:Benzofurans / Q000032:analysis* / Q000737:chemistry; D001628:Beverages / Q000032:analysis*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D045792:Norisoprenoids / Q000032:analysis; D009862:Online Systems; D013662:Tea / Q000737:chemistry*; D019207:beta Carotene / Q000032:analysis
chemical_list: D001572:Benzofurans; D045792:Norisoprenoids; D013662:Tea; D019207:beta Carotene; C008157:beta-ionone; C010711:dihydroactinidiolide