COMPOSITION OF SAN-MARZANO TOMATO VARIETIES

Compositional characteristics of 11 lines of San Marzano tomatoes have been determined. The results come from a 3 year study (1989-1991), du ring which the fol lowing parameters were evaluated: total solids, sol uble solids, organic acids (citric, malic, succinic and ascorbic), sug ars (glucose, fructose and sucrose), cations (Na, K, Mg and Ca), anion s (sulfate, phosphate and chloride), amino acids and formol value. The mean pH value of the San Marzano lines was 4.6, a value somewhat high er than that of the hybrid varieties usually employed in the food indu stry. Instead, the contents of Na+, K+, Ca2+ and Mg2+ ions were close to those of hybrid varieties. Three amino acids, i.e. glutamic acid, g amma-aminobutyric acid and glutamine, represent about 65% of the total free amino acid content. Although, in the case of glutamic acid, the mean value was close to that of the hybrid varieties (240 mg/100 g), t he variability of the content in the lines was high (between 110 and 3 60 mg/100 g). The elevated heterogeneity of the San Marzano population s strongly influenced the difference in parameters studied. From a com positional viewpoint it is very difficult to differentiate pure San Ma rzano lines from hybrids without a careful morphological examination o f the product.