Effect of Agronomical Practices on the Nutritional Quality of Virgin Olive Oil at Different Ripening Stages

摘要

There is a need to verify the quality of organically produced olive oils and to compare them to conventional ones. The objective of this study was to assess possible differences in nutritional quality between agronomic practices in Picual and Hojiblanca olive oil varieties at different stages of olive ripeness. The results showed that organic versus conventional cultivation did not consistently affect acidity, peroxide index or spectrophotometric constants of the virgin olive oils considered in this study. On the contrary, phenol content, oxidative stability, tocopherol content and fatty acid composition were affected by the agronomical practices. Principal component analysis indicated that linolenic acid and beta-tocopherol were mainly responsible for discriminating Hojiblanca organic oils, whereas total phenols, palmitoleic acid and alpha-tocopherol were the major contributors to differentiating Picual conventional oils. Lignoceric and stearic acids were related to oils from unripe and ripe olive fruits, respectively. Long-term experiments are required to confirm these results.