Carotenoid-Related Volatile Compounds of Tobacco (Nicotiana tabacum L.) Essential Oils

Tobacco (Nicotiana tabacum L.) aroma is an important attribute of tobacco quality and is influenced by a variety of minor chemical components, including carotenoid degradation products. The objectives of this work were to determine the content of the most important fragrance-shaping carotenoid degradation products in the essential oils (EOs) of the three types of Bulgarian tobacco—Oriental (OR), flue-cured Virginia (FCV), and Burley (BU)—and to compare them with other aromatic products from tobacco. The content of total carotenoids and β-carotene was highest in BU tobacco (22.23 and 20.34 mg/100 g DW, respectively), followed by OR (13.60 and 12.09 mg/100 g DW in variety “Plovdiv 7” (Pd7); 6.27 and 5.45 mg/100 g DW in “Krumovgrad” (Kr), and FCV (5.93 and 3.73 mg/100 g DW). EOs were obtained by hydrodistillation in an acidified medium, and the main aroma-impact compounds from carotenoid degradation (identified by GC-MS) were as follows: FCV-α-ionone (0.61 mg/100 g DW), dihydro-β-ionone (0.96 mg/100 g DW), β-damascenone (1.26 mg/100 g DW); BU-α-ionone (0.73 mg/100 g DW), dihydro-β-ionone (1.19 mg/100 g DW), β-damascenone (1.35 mg/100 g DW); OR(Kr)-α-ionone (0.20 mg/100 g DW), β-ionone (1.08 mg/100 g DW), dihydro-β-ionone (1.34 mg/100 g DW), β-damascenone (0.36 mg/100 g DW); OR(Pd7)-α-ionone (1.43 mg/100 g DW), dihydro-β-ionone (1.73 mg/100 g DW), β-damascenone (1.23 mg/100 g DW). Ionone and its derivatives were not identified in the aroma extraction products concrete, resinoid, or absolute. The results suggest that temperature, pH of the medium, process duration, and possibly other unknown factors affect carotenoid transformation. The study provides insight into the composition of tobacco EOs and may be of interest to the fragrance industry.