The total steroidal alkaloid compositions of the mature-harvested fruits of the tomato cultivar Allround (Lycopersicon esculentum), of the species L. hirsutum glabratum, resistant to the glasshouse whitefly (Trialeurodes vaporariorum), and of four resistant lines were determined by capillary gas chromatography. The contents of α-tomatine in the red-ripe fruits of ‘Allround’ and in those of the lines were low (≤5 mg/kg fresh weight). The green-mature fruits of the wild species had a high content (3390 mg/kg fresh weight) of α-tomatine. The total alkaloid profiles of ‘Allround’ and of the lines were similar. Comparison of flame ionisation detector response with thermoionic detector response indicated that in addition to tomatidine, the aglycone of α-tomatine, a small amount of one other steroidal alkaloid might be present in ‘Allround’ and in the lines. The wild species contained five compounds which possibly are steroidal alkaloids.
The safety level of α-tomatine in tomatoes is discussed. It was concluded that, in respect of the glycoalkaloids of the mature-harvested fruits, the resistant tomato breeding lines are as safe for human cosumption as the standard cultivar.
Lycopersicon esculentumtomatoL. hirsutum glabratumTrialeurodes vaporariorumglasshouse whiteflyresistancetomatineglycoalkaloids, capillary gas chromatography