Carotenoids of dry tomato residues were extracted by two systems of solvent
namely acetone - petroleum ether (b . p. 40 – 60 °C)(System 1) and acetone – hexane – ethanol (1 : 2 : 1) (System 2) . The pigments in extracts were identified by HPLC technique . From the 17 pigments identified , lycopene was the major .
System 2 gave higher percentage of lycopene (80.9 %) as compared with system 1 which gave 39.6 % . Formation of 37.7% of lycopene diepoxide might be the reason for the reduced percentage of lycopene when System 1 was used . β – Carotene was extracted effeceintly (2.51%) by system 2 , while the percentage decreased to 1.7% when using System 1 due to oxidation which produse 1.8% of β – Carotene diepoxide. On the contrary Lycoxanthin was efficiently extracted by system 1 (8%) rather than system 2 (2.1%) . Cis – isomers , mainly Cis – Lycopen – 1 was extracted by both systems (6.6 and 9.6% respectively). The appearance of these isomers may be due to exposure to light with oxygen