Variability in the content of soluble sugars and cell wall polysaccharides in red-ripe cherry and high-pigment tomato cultivars
2008
Lenucci, Marcello Salvatore | Leucci, Maria Rosaria | Piro, Gabriella | Dalessandro, Giuseppe
BACKGROUND: Soluble sugars and cell wall polysaccharides are well known for contributing to a range of 'quality' characteristics of fresh vegetables such as flavour, texture and healthy properties. Red-ripe berries of 14 cultivars of cherry tomatoes and four cultivars of high-pigment tomato hybrids, cultivated in the south of Italy, were analysed for their content of these important qualitative parameters.RESULTS: Sakura appeared to be the cultivar with the highest amount of soluble sugars (53 g kg⁻¹ fresh weight (f.w.)), mainly glucose and fructose, and, hence the 'sweetest' among cherry tomatoes. High-pigment tomatoes, especially HLY02 and HLY13, showed a soluble sugar content much lower than cherry tomatoes, as expected for industrial, normal-size tomatoes. Variations in the fructose/glucose ratio, of between 0.68 and 1.48, were evidenced among the different tomato cultivars. Cell wall polysaccharides isolated from whole fresh red-ripe berries of each cultivar were analysed chemically. The amount of matrix polysaccharides (0.9-3.4 g kg⁻¹ f.w.) and cellulose (0.16-1.86 g kg⁻¹ f.w.), as well as their glycosidic composition, showed significant differences among the different cultivars. Cellulose to matrix polysaccharide ratio was highly variable and ranged between 0.06-1.44 and 0.17-0.77 in cherry and high-pigment tomato cultivars, respectively.CONCLUSION: The differences evidenced in the total soluble sugar and cell wall polysaccharide composition, not only among different types of tomatoes but also different cultivars within the same typology, may play a fundamental role in the quality of tomatoes and deserve further investigations.
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