Ángeles F. Recamales

Influence of cultivar and culture system on nutritional and organoleptic quality of strawberry.

BACKGROUND Strawberries are widely appreciated and consumed as a pleasant-tasting fruit either in fresh form or as processed product. Of the many factors which can affect the quality of fruit (sensorial and nutritional), the cultivar is especially important, but it is also affected by crop conditions. The main characteristics related to the fruit quality and nutritional attributes were assessed in several varieties of strawberry grown in soilless and soil culture. The effect of different cultivars and cropping systems on selected quality parameters, were assessed by applying multivariate statistical methods, such as principal component analysis and partial least square discriminant analysis (PLS-DA). RESULTS Differences among cultivars were observed based on the mineral composition and glucose and fructose concentrations in both cultivation systems. However, no significant differences between cultivars were detected in sourness. Tamar and Camarosa were the sweetest cultivars among those grown in soilless and soil system, respectively. Both varieties also had the highest total sugars/total acids ratio. The comparison between strawberries cultivated in soil and soilless systems also revealed significant differences in the mineral composition, content of sugars and related parameters. CONCLUSION Good discrimination was observed between cultivars of conventional crops, whereas no clear separation between cultivars grown in the soilless system was achieved by PLS-DA. PLS-DA also allowed differentiation of samples by type of crop (soilless vs. conventional crop). This information could be useful for selection of growing conditions and high-quality cultivars.

Multivariate statistical analysis of the color-anthocyanin relationships in different soilless-grown strawberry genotypes.

Apart from the need to assess the color of foods due to its preponderant role in their acceptability, there is currently a new trend consisting in the study of the relationships between the color and the pigments accounting for it. The color of five strawberry varieties cultivated in two different soilless systems has been studied, and an array of multivariate statistical methods have been performed to single out the color parameters that best discriminate among the different samples surveyed and to correlate them with the pigment content. It is concluded that there is not a direct relationship between the external and flesh colorations of the berries. Additionally, after discriminant methods were applied, it was noticed that, taking into account the strawberry varieties, >90% of the cases could be correctly classified, a noticeably lower percentage of correct classification (around 60%) being obtained when the type of cultivation system was selected as the criterion for discrimination. The best correlations of pigment-color coordinates were found between pelargonidin-3-rutinoside and the external a* (r= -0.87) followed by pelargonidin-3-glucoside and the internal L* (r= -0.72).