A digital service from FCT Publication
Segurança e Autenticidade de Azeitonas e Azeites Varietais
| Summary: | Olive oil has an important role in Portugal, both economic and social. This research work aimed to contribute to the improvement and development of the quality of olive oils with Protected Designation of Origin from Trás-os-Montes region. Among several possibilities to accomplish this goal, the following two were chosen: 1.The characterization of chemical compounds of olive oil and the influence of genetic factors (cultivar). 2 The evaluation of pesticide residues from phytosanitarian olive treatments which may be present in the final product, olive oil. Different analytical methods were developed and optimized based on chromatographic techniques - HPLC and GC, using different detectors (ELSD, FLD/DAD and MS/MS in HPLC and ECD/NPD, FID and MS in GC) according to the specificity of the substances to analyze and to the demanded levels of sensitivity. As far as characterization and authenticity of olive oils were concerned the selected analytical parameters were a) triacylglycerols, b) esterified phytosterols and free phytosterols and c) tocopherols and tocotrienols. Regarding safety, methodologies for detection and quantification of a) multiresidue of pesticides, fenthion and its metabolits and phosmet and its metabolits were developed. For the extraction of the studied substances several procedures were enhanced (LLE, MSPD and QuEChERS), in order to achieve good extractive results and minor "environmental impact". Based on the quantitative profile of triacylglycerols it was possible to differentiate monovarietal olive oils of Cvs. Cobrançosa, Madural and Verdeal Transmontana. The profiles of esterified phytosterols and free phytosterols were qualitatively and quantitatively different in olive oils with Protected Designation of Origin from Trás-os- Montes region. The profile of tocotrienols and tocopherols proved to be similar in PDO olive oils from Trás-os-Montes and from Alto Alentejo. In olive samples of Cv. Cobrançosa, which were harvested during three consecutive years throughout the security interval (7 weeks after pesticide spraying) the levels of residual pesticides (dimetoate, fenthion and phosmet) together with its metabolits have always been significantly lower than LMR established. Analyses carried out in olive oil samples, during the three years of the research study, from the olives of the same cultivar which were exposed to the same conditions, presented an inferior level of pesticide residue compared to the pesticide residue level revealed in olives. |
|---|---|
| Subject: | Nutrition and Food Chemistry Nutrição e Química dos Alimentos Porto |
| Country: | Portugal |
| Document type: | doctoral thesis |
| Access type: | Open |
| Associated institution: | Repositório Aberto da Universidade do Porto |
| Language: | Portuguese |
| Origin: | Repositório Aberto da Universidade do Porto |
| Summary: | Olive oil has an important role in Portugal, both economic and social. This research work aimed to contribute to the improvement and development of the quality of olive oils with Protected Designation of Origin from Trás-os-Montes region. Among several possibilities to accomplish this goal, the following two were chosen: 1.The characterization of chemical compounds of olive oil and the influence of genetic factors (cultivar). 2 The evaluation of pesticide residues from phytosanitarian olive treatments which may be present in the final product, olive oil. Different analytical methods were developed and optimized based on chromatographic techniques - HPLC and GC, using different detectors (ELSD, FLD/DAD and MS/MS in HPLC and ECD/NPD, FID and MS in GC) according to the specificity of the substances to analyze and to the demanded levels of sensitivity. As far as characterization and authenticity of olive oils were concerned the selected analytical parameters were a) triacylglycerols, b) esterified phytosterols and free phytosterols and c) tocopherols and tocotrienols. Regarding safety, methodologies for detection and quantification of a) multiresidue of pesticides, fenthion and its metabolits and phosmet and its metabolits were developed. For the extraction of the studied substances several procedures were enhanced (LLE, MSPD and QuEChERS), in order to achieve good extractive results and minor "environmental impact". Based on the quantitative profile of triacylglycerols it was possible to differentiate monovarietal olive oils of Cvs. Cobrançosa, Madural and Verdeal Transmontana. The profiles of esterified phytosterols and free phytosterols were qualitatively and quantitatively different in olive oils with Protected Designation of Origin from Trás-os- Montes region. The profile of tocotrienols and tocopherols proved to be similar in PDO olive oils from Trás-os-Montes and from Alto Alentejo. In olive samples of Cv. Cobrançosa, which were harvested during three consecutive years throughout the security interval (7 weeks after pesticide spraying) the levels of residual pesticides (dimetoate, fenthion and phosmet) together with its metabolits have always been significantly lower than LMR established. Analyses carried out in olive oil samples, during the three years of the research study, from the olives of the same cultivar which were exposed to the same conditions, presented an inferior level of pesticide residue compared to the pesticide residue level revealed in olives. |
|---|