Physical and chemical characterization in fruit from 22 summer squash (Cucurbita pepo L.) cultivars

•Commercial zucchini cultivars gave the highest carotenoid content.•This study revealed zeaxanthin levels higher than any previously reported.•Multivariable analysis were used based on 13 fruit quality variables.•The most important were color, dry matter, °Brix, citric and carotenoid.

Physical and chemical characters of 22 summer squash genotypes (traditional and commercial cultivars) were evaluated in fruit using correlation and principal component analysis. External and internal fruit quality was assessed by standard parameters (fruit weight and dimensions, firmness, color, dry matter, soluble solids, pH, total acidity) and nutritional quality (individual and total carotenoid content) in fruit epicarp and mesocarp. Some of the cultivars showed distinctive and interesting characters in mesocarp, such as high soluble solid (4.7 °Brix: Cu-8 traditional cultivar), dry matter (6.6 g 100 g−1: Cu-36 commercial cultivar), β-carotene (45 mg kg−1 dry matter: Cu-11 traditional cultivar) and total carotenoid contents (371 mg kg−1 dry matter: Cu-29 commercial cultivar). Moderate and significant positive relation was found between epicarp and mesocarp color parameter (b*) with lutein and total carotenoid contents in mesocarp (r > 0.52***), suggesting that indirect selection for high carotenoid content will be successful. Multivariable analysis allowed the grouping of variables, the most important being the a* and b* parameters (in epicarp and mesocarp), dry matter, soluble solid, total acidity, lutein, β-carotene and total carotenoid contents (in epicarp). Some cultivars may serve as a source of desirable genes to develop improved varieties that respond to the new needs of the market.