QUALITY OF STRAWBERRY 'CAMAROSA' WITH DIFFERENT LEVELS OF NITROGEN FERTILIZATION

‘Camarosa’ cultivar berries were evaluated to asses the influence of different nitrogen fertilizations on their quality.There were 4 levels of nitrogen fertilization: type 1 without nitrogen; types 2, 3 and 4 with 5 g/m², 10 g/m² and 15 g/m² of nitrogen respectively. Samples of 6 ripe fruits, from each modality (4 modalities) and repetition (4 repetitions) were picked up periodically and analyzed at the Post-harvest laboratory, Évora University. The following variables and tests were performed to evaluate fruit quality: weight, external color (L* a* b*), visual aspect penetration test, Soluble Solids Content, titrable acidity and aroma. The results for texture were significant for the ratio maximum force/deformation, and the strawberries grown without nitrogen fertilization are significantly different from all the others. The electronic nose seems to be a good method to determinate wich strawberries were produced with different nitrogen fertilization, mainly modality 0 from the others; however it does not make any distinction for those obtained from modality 2 and 3. The PCA analysis indicates that the factor 1 explains 82% of the total variance. A general evaluation of the results make evident that fruits without nitrogen fertilization are clearly distinguished from those of modality 2 (5 g/m²) that reveal a possible increase of quality; berries obtained from modalities 3 and 4, do not show any interesting changes.