Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Establishment of authenticity and typicality of sugarcane from Madeira Island, and its derivative sugarcane honey, based on molecular, chemical and chemometric analysisPublication . Silva, Pedro Miguel Capêlo da; Câmara, José de Sousa; Nunes, Fernando Hermínio Ferreira MilheiroFood authenticity has become a worldwide concern, foresting the importance of the development of strategies to guarantee the quality and safety of food products. The purpose of this doctoral thesis was the establishment of the typicality and authenticity of sugarcane cultivars from Madeira Island, and its main derivative, sugarcane honey. The followed strategy was based on the identification of typical volatile, sugars and furan derivatives profiles in sugarcane honey processed by the certified producer Fábrica Mel-de-Cana Ribeiro Sêco, and compare it with sugarcane-based syrups from non-certified regional producers and from producers from different geographical regions. Also, the typical volatile profile throughout all stages of sugarcane honey processing were identified during four years, allowing the evaluation of influence of each stage in the formation of its typicality. In addition, the typical volatile profile of all sugarcane cultivars currently cultivated in Madeira Island were identified, namely amarela, canica, roxa, radiada, verde and violeta. Different analytical methodologies based on effective extractive techniques and high-resolution chromatographic methods were successfully developed, optimized and validated, namely solid-phase microextraction combined with gas chromatography-mass spectrometry for the volatile profile, microextraction by packed sorbent combined with ultra-high performance liquid chromatography with diode-array detector for the furan derivatives profile, and ultrasound-assisted liquid-liquid extraction combined with liquid chromatography with a refractive index detector for sugars profile. Furthermore, an innovative and powerful Quality-by-Design approach was selected for development of the methodologies used for quantitation of furan derivatives and SGs. An exhaustive chemometric analysis based on one-way ANOVA, principal component analysis, partial least squares, linear discriminant analysis and hierarchical clustering analysis was successfully applied to recognize the typical profiles of sugarcane honey. This doctoral thesis represents the first attempt to define the typicality, authenticity and traceability of sugarcane honey from Madeira Island, providing a highly valuable information to support its European Union certification.
- Residue analysis of insecticides in potatoes by QuEChERS-dSPE/UHPLC-PDAPublication . Reis, Débora; Silva, Pedro; Perestrelo, Rosa; Câmara, José S.Insecticides are broadly applied in agriculture to defend crops from illnesses and pest attacks, consequently guaranteeing high production. However, their residual deposits in food products are becoming a main concern with regard to human consumption. As such, sensitive analytical methods should be developed to assess, prevent and control insecticide residues. In this research, an accurate, fast and reliable residual analytical method, that is quick, easy, cheap, effective, rugged and safe, combined with dispersive solid phase extraction (QuEChERS-dSPE), was developed for the determination of the most common insecticides used in potatoes cultivation (chlorpyrifos, λ-cyhalothrin, deltamethrin and acrinathrin), using an ultra-high performance chromatography photodiode array detector (UHPLC-PDA). The most influential extraction and instrumentation parameters that affect the method’s performance, such as extraction solvent, ratio salts, sorbents, stationary phases, gradient conditions and eluents, were assessed. Under the ideal conditions, good linearity (0.992–0.998), limits of detection (0.02–0.47 µg/kg) and quantification (0.06–1.58 µg/kg), recovery (94.1 to 112%) and precision (relative standard deviation <18%) were achieved for spiked levels between 2.5 and 50 µg/kg. The obtained results revealed that the potatoes analyzed do not represent any concern for human healthy, as the insecticide residues detected were lower than the maximum residue limits set by the European Union, Codex Alimentarius, and other organizations.
- Application of quality-by-design approach in the analytical method development for quantification of sugars in sugarcane honey by reversed-phase liquid chromatographyPublication . Silva, Pedro; Silva, Catarina L.; Perestrelo, Rosa; Nunes, Fernando M.; Câmara, José S.Produced in Madeira Island from regional sugarcane cultivars through a traditional manufacturing and storage process, sugarcane honey (SCH) is a black syrup recognized by its excellent quality. Its economic value has led to the emergence of adulterated SCH, whereby the identification of molecular markers became an essential task in order to overcome the fraudulent activities, protect its authenticity, and guarantee the consumer safety. In the present study, an analytical strategy based on ultrasound-assisted liquid liquid extraction (USA-LLE) followed by reversed-phase liquid chromatography with a refractive index detector (LC-RI) was developed for the determination of sugars (glucose, fructose, sucrose, xylose, and mannose) in SCH samples from certified producers, supported on analytical quality-by-design (AQbD) approach, as a useful tool to establish its typicality. The application of AQbD was based on analytical risk assessment, multivariate statistics and quality control procedures for definition of the Method Operable Design Region (MODR). The optimal conditions into MODR were accomplished using BEH Amide column operating at a temperature of 80 °C and a flow rate of 300 μL min−1 , with a mobile phase composed by acetone and water (85:15, v v−1 ) at a flow rate of 1.0 mL min−1 . The robustness was determined by Monte Carlo simulation and capability analysis. The concentration-response function for all sugars was described by polynomial models. Accuracy was presented by recovery values between 98.2 and 119.5%. The analytical figures of merit validated the utility of AQbD in the systematic design of a LC-RI method with fine sensitivity for sugar analysis in SCH.