Superior nutritional characteristics
Darrigues A, Schwartz SJ, Francis DM. Optimizing sampling of tomato fruit for carotenoid content with application to assessing the impact of ripening disorders. J Agric Food Chem 2008 Jan;56(2):483-7.
Color defines one aspect of quality for tomato and tomato products. Carotenoid pigments are responsible for the red and orange colors of tomato fruit, and thus color is also of dietary interest. The aims of this study were (1) to determine the relative importance of field sampling and analytical replication when measuring lycopene and beta-carotene in tomato fruit and (2) to determine the effect of yellow shoulder disorder (YSD) on the content of lycopene and beta-carotene in tomato juice and tissue. Our results show that increasing biological replications is an efficient strategy for reducing the experimental error associated with measurements of lycopene and beta-carotene. Analytical replications did not contribute significantly to observed variation, and therefore experimental efficiency will be gained by reducing analytical replications while increasing field replication. We found that YSD significantly reduces lycopene in affected tissue and in juice made from affected fruit. In contrast, beta-carotene concentrations were only reduced in affected tissue but were not significantly reduced in juice. With increasing interest in biofortified crops, modulating the carotenoid profile in tomato by minimizing YSD symptoms represents a strategy for improving tomato fruit quality that is currently supported by grower contract structure and processor grades.
Gazula A, Kleinhenz M, Scheerens JC, Ling PP. Anthocyanin levels in nine lettuce (Lactuca sativa) cultivars: Influence of planting date and relations among analytic, instrumented, and visual assessments of color. Hortscience 2007.
Leaf samples collected from field plots of nine lettuce cultivars established in the early (ES) and late (LS) summer of 2002 and 2003 in Celeryville, Ohio, were subjected to spectrophotometric measurement of anthocyanin concentrations or color analysis based on colorimeter and spectroradiometer readings and human panelist ratings. Interactions among year (Y), transplanting date (TD), and cultivar (C) main effects for anthocyanin concentration were significant as a result of shifts in response magnitude but not direction. Anthocyanin levels were higher after LS than ES transplanting regardless of Y and C. The effects of TD were pronounced in 2002, when differences in average daily temperature between ES and LS transplantings tended to be larger. Also, regardless of Y and TD, anthocyanin levels followed the pattern ‘Impuls’ > ‘OOC 1441’ > ‘Valeria’ > ‘OOC1426’ > ‘Lotto’ > ‘SVR 9634’ > ‘OOC 1434’ = ‘OOC 1310’ > ‘Cireo’. Treatment-based color differences were also evident in colorimeter and spectroradiometer readings. Also, panelists differentiated samples grown in 2003 based on red color intensity. Correlations between analytic, instrumented, and human panelist-based measures suggest instrumented assessments of red coloration may serve as proxies for direct measures of anthocyanin levels or human panelist ratings, particularly if the aim is to establish color differences between major experimental groups and assign quantitative, repeatable values to red color intensity.