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Composition of tomatoes and tomato products in antioxidants (WG1) page 88
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9.1.4 Peels from peeled tomatoes
Peels discarded during processing are taken directly from skin eliminator .
Peels are appropriately diluted with distilled water and treated in a Waring Blender
homogenizer maintained under vacuum to obtain very small pieces. Right after, peels are
broken using colloid grinding mill.
Peels are suddenly disaerated and analyzed or stocked under proper conditions.
The amounts of fresh tomatoes or preserved tomatoes to weight for the extraction are
considered on the basis of the theoretical concentrations of pigments. In the previous
examples we have :
2 – 5 g for tomato peels; 5 g for tomato puree; 10 g for crushed tomatoes and for
peeled tomatoes; in the case of tomato paste we must dilute the sample to reach the same
soluble solids concentration of tomato puree (8°Bx), and to weight the same amount (5g).
9.1.5 Extractions
The extraction method considered is similar to the D.J.Hart and K.J. Scott’s method
(1995) with some modifications devised to obtain better separations of pigments in tomato
matrix and is well described in the work published in Industria Conserve, 74, 1999, (341-357)
by R. Tamburini, L. Sandei et al.
9.1.6 Recommandations for working with lycopene
a) Lycopene and its derivatives are sensitive to sunlight, artificial light and
oxidation. Therefore, it is necessary to avoid exposure to light and oxygen as
much as possible while preparing sample for testing;
b) it is recommendable to work with amber glassware;
c) during all stages of determination in the laboratory, all the solutions will
contain the antioxidant BHT in a similar concentration to that of lycopene;