Residual lycopene content assessment.Tomato lycopene content was measured before and after drying by using a spectrophotometer (UV–Visible spectrophotometer JENWAY 6705). Lycopene
was extracted from 1.5 to 2 g of tomato sample in 40 mL of extraction solution (hexane–methanol–acetone: 50/25/25) containing
0.05% of BHT (Butyl Hydroxy Toluene). The mixture was agitated
for 15 min using a vortex. After agitation, 5 mL of distilled water
were added then agitated again for 5 min. After the second agitation the flask was left at rest for 5 min before the lycopene absorbance spectrometric measurement was carried out (Fish et al.,
2002). The absorbance of the hexane layer was measured in a
1 cm pathlength quartz cuvette at 502 nm versus a blank of hexane
solvent. The lycopene content was estimated as mg/1000 g (w.b)
tomato or by-products based on the following equation.