217 research outputs found
Evolution of ochratoxin A content from must to wine in Port wine microvinification
To study the evolution of ochratoxin A (OTA)
content from must to wine during the making of Port
Wine, grapes from the five most common varieties of
Port Wine were harvested and combined in equal percentages
in order to perform microvinifications. Three
sets of assays were studied: a blank (A), where the most
common Port Wine-making process was used; in the
second (B), a solution of OTA was added to the initial
must; in the third (C), the grapes were aspersed with an
inoculating solution of OTA-producing fungi. Samples
were collected, in duplicate, on four different occasions
throughout the process. The influence of the addition of
SO_2 to the must was also assessed in each set. The
quantification of OTA was based on the standard reference
method for wines (European Standard prEN
14133), which includes clean-up via immunoaffinity
columns and HPLC with fluorescence detection. The
limits of detection were 0.076 μg/l for wine and
0.114 μg/l for must. The method was validated by
assessing the precision, accuracy and by obtaining an
estimate of the global uncertainty. Overall, the levels of
OTA observed during the vinifications dropped by up to
92%, and no grapes used in this work were contaminated
naturally.The authors wish to thank the support of the INIAP—Instituto Nacional de Investigação Agrária e das Pescas (Portugal), through the Program AGRO, Medida 8.1, and all the personnel and facilities at the Centro de Estudos Vitivinícolas do Douro (Peso da Régua, Portugal) and the Instituto dos Vinhos do Douro e Porto (Porto, Portugal)
Metodologia de medida da difusividade térmica por RMN-CWFP.
bitstream/CNPDIA-2009-09/11832/1/CT72_2006.pd
Worldwide interlaboratory study on the determination of ochratoxin A in different wine type samples
Interlaboratory studies are decisive tools to help the validation of a specific analytical methodology or to assess the reproducibility of the use of different methods to analyze a given compound or compounds in certain sample matrices. In this work, homogeneous samples of two white wines (“White Wine” and “White Liqueur Wine”) and one red wine (“Red Fortified Wine”) from Portugal with different production techniques and characteristics, namely in alcohol strength (10.5%, 16.0% and 19.0% ethanolic content, respectively), were analyzed for their contents in ochratoxin A (OTA), a mycotoxin generated from fungal contamination. White Liqueur Wine was naturally contaminated, whereas the other two wine type were spiked with ethanolic OTA solutions. The participation of 24 laboratories from 17 countries of five continents was ensured for this study. Although with no restrictions in terms of analytical methodology to employ, 75% of the laboratories resorted to immunoaffinity columns clean-up followed by high performance liquid chromatography with fluorescence detection (HPLC-FD), most of them in accordance with the European Standard EN 14133. For White Wine samples, the general mean OTA concentration was 1.96 μg/l (two outliers) with interlaboratorial standard deviation (sL) of 0.53 μg/l; for White Liqueur Wine, mean of 1.59 μg/l (one outlier), with sL = 0.59 μg/l; and for Red Fortified Wine, mean of 2.73 μg/l (no outliers), with sL = 0.96 μg/l. Outliers were determined by Cochran and Grubbs tests. The Horrat index, recommended by the Association of Official Analytical Chemists (AOAC) for the quality assurance of the collaborative study was, on average, 1.7. This study proved that OTA determination in wines is reproducible, regardless of the methodology employed.INIAP (Portugal), through the Program
AGRO
Ozone against mycotoxins and pesticide residues in food: Current applications and perspectives
Food safety may be compromised by the presence of chemical contaminants, such as mycotoxins and pesticide residues. Mycotoxins are natural contaminants produced by certain species of filamentous fungi and can cause toxic effects on human health. Pesticide residues are any specified substance in food resulting from the use of a pesticide with toxicological significance. To protect consumers from these toxic substances, different food regulatory agencies have set maximum levels permitted in different raw materials and processed foods. However, recent research has demonstrated a high incidence of both mycotoxins and pesticide residues (not simultaneously) in foods marketed all around the world, sometimes with levels above the regulated limits. One way to reduce such contaminants is to use ozone (O3) in food processing. Due to its high potential as an oxidant, O3 or the radicals generated in the ozonation process react with mycotoxins and pesticide residues that lose their toxicity due to molecular degradation. In this review paper the recent research into using O3 for gaseous ozonation and ozonized water to decontaminate food by eliminating and/or reducing mycotoxins and pesticide residues are discussed. Also the changes promoted in food quality attributes, the possible formation of degradation products of toxic relevance, as well as some perspectives for the future use of this technology in food processing are explored.National Counsel of Technological and Scientific Development, BrazilCoordenação de Aperfeiçoamento de Pessoal de Nível Superior, BrazilRio de Janeiro State Foundation to Support ResearchAuthors are grateful for the financial support provided by CNPq (National Counsel of Technological and Scientific Development, Brazil), CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, Brazil) and FAPERJ (Rio de Janeiro State Foundation to Support Research)
Chemical composition and bioactivity of essential oils and extracts from Oregano from Madeira Island, Portugal
In the course of ongoing investigations on polymorphic Lamiaceae species, we
studied Origanum vulgare spp. virens growing wild in several locations of Madeira
Island, Portugal. Variation in essential oil composition with climate conditions was
studied. The antimicrobial activity of the various essential oils was determined
against 10 strains of bacteria and yeasts, usually found as human pathogenic or food
contaminants. The essential oils inhibited all the bacteria tested excepting for P.
aeruginosa. The most sensitive microorganism was M. smegmatis with MIC = 25 µg
ml-1 for two of the oils. The results of this study suggest a potential application of
these oils in preventing the human pathogenic and food contaminant
microorganisms growth. Radical scavenging capacity of essential oils and solvent
extract (hexane, chloroform, ethyl acetate and methanol) were also determined,
since interest of oregano resides in both non polar and polar fractions, all known by
their very high antioxidant activity. From the hexane fraction, we obtained a large
amount of 1-hexacosanol, C26H54O, a long chain alcohol, which was previously
extracted in the non-esterified form only from Hygrophila erecta.info:eu-repo/semantics/publishedVersio
Modelling the habitat preferences of the NE-Atlantic Sea cucumber Holothuria forskali : demographics and abundance
This work was funded by the Operational Program Mar2020 MAR-02.01.01-FEAMP-0052 “Newcumber - Avanços para o cultivo sustentável de pepinos do mar”. This work was also supported by national funds through FCT - Fundação para a Ciência e a Tecnologia, I.P., within the scope of the projects (https://doi.org/10.54499/UIDB/04292/2020, and https://doi.org/10.54499/UIDB/00006/2020) and the Associate Laboratory ARNET (https://doi.org/10.54499/LA/P/0069/2020), A.C. Brito with the Scientific Stimulus Program – CEECIND/00095/2017, A.P. with the under the Scientific Employment Stimulus - Institutional Call - CEECINST/00051/2018 and Francisco Azevedo e Silva and João Trigo de Sousa through the individual grants (SFRH/BD/09563/2020 and SFRH/BDANA/02949/2023).Sea cucumbers' historical demand, together with the depletion of several traditional species in the market, has popularized new target species from new fishing grounds. Holothuria forskali is one of those emergent species in the trade market. However, it is a species for which there is no relevant information to allow sustainable stock management. Fundamental knowledge of the populations' structure and habitat preferences are key elements without which any measure is inconsequent. This work aims to fill that gap by modelling temporal and spatial patterns of abundance and demographic structure of this species in a NE-Atlantic area, as a function of environmental features. For a period of 15 months, nine regular sampling campaigns collected data on density, individual length, individual conditions of occurrence (e.g. sheltered, on sand, on algae cover) and environmental parameters (water column, sediment, substrate cover and type), using random transects throughout a costal rocky-reef, considering habitat heterogeneity and substrate types. To determine the species' habitat preferences Generalized Linear Models were used to model density and demographic structure of the species as a function of environmental conditions. The models revealed that the main drivers shaping the distribution of H. forskali are neither abiotic nor biotic parameters of the water column, but physical stressors, like current intensity and depth, and substrate type in a patchy distribution pattern. Estuarine conditions are generally avoided, although with a size-dependent opportunistic strategy. Larger individuals show temporal and spatial displacement patterns towards suitable reproductive conditions (pre-breeding aggregation) and favourable feeding grounds and smaller size-classes tend to aggregate in higher numbers in more stable environments. Sustainable sources for market supply, like aquaculture, are still a long way from commercial production. So, these results are fundamental to support effective conservation measures for stock management of H. forskaliPublisher PDFPeer reviewe
Allometric relationships to assess ontogenetic adaptative changes in three NE Atlantic commercial sea cucumbers (Echinodermata, Holothuroidea)
This study was financed by the Operational Program Mar2020 nº MAR-02.01.01-FEAMP-0052 “Newcumber—Avanços para o cultivo sustentável de pepinos-do-mar”. It received further financial support from Fundação para a Ciência e a Tecnologia with project UIDB/04292/2020; A.C. Brito and A. Pombo through the Scientific Employment Stimulus Programmes (CEECIND/00095/2017 and CEECINST/00051/2018); and Francisco Azevedo e Silva through the individual research Grant 2020.09563.BD; Also, T. A. Marques and C. Rocha thank partial support by CEAUL (funded by FCT—Fundação para a Ciência e a Tecnologia, Portugal, through the project UIDB/00006/2020).Holothuria arguinensis, Holothuria mammata and Holothuria forskali are three common sea cucumber species found in the NE Atlantic, traded in international markets and susceptible to capture. Allometric relationships reveal if the scaling relationships between biometric characters are proportional with growth, being a useful tool to understand species growth strategies. Allometric relationships of the three species were estimated and compared between them and with populations from different regions. These allometric relationships revealed that the three species have negative allometric growth. However, they have different growth strategies between them and reveal different regional intra-specific growth strategies when compared to other populations, suggesting ontogenetic adaptation as a consequence of external factors. PostprintPeer reviewe
Inhibitor of cysteine protease and mortality of Diaphorina citri.
The Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), is considered an important pest of citrus by its ability to transmit the HLB disease. Thus, the aim of this study was to evaluate the potential of protease inhibitors for the control of this insect. The tests were performed with Murraya paniculata plants. The following aqueous solutions were applied: (1) distilled water (control), (2) Triton X-100 (0.1 m L-1) and (3) cysteine proteinase inhibitor E-64 (0.05 mg mL-1) and Triton X -100 (0.1 mL L-1). Four treatments were performed: solutions (1), (2) and (3) were applied four days before the release of the insects on the plants and for the last treatment, solution (3) was applied immediately before the insects release. The solutions were applied to the stem of the plant, 20 mL per plant. Were used five plants per treatment. Ten adults of D. citri were released on each plant after four hours of starvation. Each plant was maintained in a cage and mortality was observed for five days. The data was analyzed by Tukey test (p>0.05). There was no significant difference in mortality of insects among the treatments. Enzymatic analysis showed that there is enzymatic activity of cysteine p roteases in the D. citri midgut, thus, the low mortality after ingestion of this compound may indicate the need to adapt the bioassay method
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