28 research outputs found
A novel online food recall checklist for use in an undergraduate student population : a comparison with diet diaries
Peer reviewedPublisher PD
Preliminary results of the project A.I.D.A. (Auto Immunity: Diagnosis Assisted by computer)
In this paper, are presented the preliminary results of the A.I.D.A. (Auto Immunity: Diagnosis
Assisted by computer) project which is developed in the frame of the cross-border cooperation Italy-Tunisia.
According to the main objectives of this project, a database of interpreted Indirect ImmunoFluorescence (IIF)
images on HEp 2 cells is being collected thanks to the contribution of Italian and Tunisian experts involved in
routine diagnosis of autoimmune diseases. Through exchanging images and double reporting; a Gold Standard
database, containing around 1000 double reported IIF images with different patterns including negative tests,
has been settled. This Gold Standard database has been used for optimization of a computing solution (CADComputer
Aided Detection) and for assessment of its added value in order to be used along with an
immunologist as a second reader in detection of auto antibodies for autoimmune disease diagnosis. From the
preliminary results obtained, the CAD appeared more powerful than junior immunologists used as second
readers and may significantly improve their efficacy
Computer-Assisted Classification Patterns in Autoimmune Diagnostics: The AIDA Project
Antinuclear antibodies (ANAs) are significant biomarkers in the diagnosis of autoimmune diseases in humans, done by mean of
Indirect ImmunoFluorescence (IIF)method, and performed by analyzing patterns and fluorescence intensity. This paper introduces
the AIDA Project (autoimmunity: diagnosis assisted by computer) developed in the framework of an Italy-Tunisia cross-border
cooperation and its preliminary results. A database of interpreted IIF images is being collected through the exchange of images
and double reporting and a Gold Standard database, containing around 1000 double reported images, has been settled. The Gold
Standard database is used for optimization of aCAD(Computer AidedDetection) solution and for the assessment of its added value,
in order to be applied along with an Immunologist as a second Reader in detection of autoantibodies. This CAD system is able to
identify on IIF images the fluorescence intensity and the fluorescence pattern. Preliminary results show that CAD, used as second
Reader, appeared to perform better than Junior Immunologists and hence may significantly improve their efficacy; compared with
two Junior Immunologists, the CAD system showed higher Intensity Accuracy (85,5% versus 66,0% and 66,0%), higher Patterns
Accuracy (79,3% versus 48,0% and 66,2%), and higher Mean Class Accuracy (79,4% versus 56,7% and 64.2%)
Fate and Prediction of Phenolic Secoiridoid Compounds throughout the Different Stages of the Virgin Olive Oil Making Process
The evolution of the main phenolic secoiridoid compounds throughout the different stages of the virgin olive oil making process—crushing, malaxation and liquid-solid separation—is studied here, with the goal of making possible the prediction of the partition and transformation that take place in the different steps of the process. The concentration of hydroxytyrosol secoiridoids produced under the different crushing conditions studied are reasonably proportional to the intensity of the milling stage, and strongly depend on the olive variety processed. During malaxation, the content of the main phenolic secoiridoids is reduced, especially in the case of the hydroxytyrosol derivatives, in which a variety-dependent behaviour is observed. The prediction of the concentration of phenolic secoiridoids finally transferred from the kneaded paste to the virgin olive oil is also feasible, and depends on the phenolic content and amount of water in the olive paste. The determination of the phenolic compounds in the olive fruit, olive paste and olive oil has been carried out by LC-MS (Liquid-Chromatography Mass-Spectrometry). This improved knowledge could help in the use of more adequate processing conditions for the production of virgin olive oil with desired properties; for example, higher or lower phenolic content, as the amount of these minor components is directly related to its sensory, antioxidant and healthy properties
Kinetics of quality degradation during storage of monovarietal extra virgin olive oils
Introduction. Lipophilic derivatives of olive secoiridois (namely, the dialdehydic form of decarboxymethyl oleuropein aglycone, the isomer of oleuropein aglycone, the dialdehydic form of decarboxymethyl ligstroside aglycone, and the isomer of ligstroside aglycone) are present in extra virgin olive oil (EVOO) due to the hydrolysis of their glycosidic precursor catalysed by endogenous glycosidases during the crushing of olive fruit. These compounds as well as alpha-tocopherol have received considerable interest due to their potential health effects, and could be used as indices to evaluate EVOO quality in addition to those established by the EU Regulations (1). Here we report on the kinetics of autoxidation and hydrolytic processes that occur during storage of EVOO, and their effects on the antioxidant content. The aim of this study was to determine whether the potential properties of EVOO antioxidants are maintained or lost during the commercial life of the product.
Materials and methods. EVOOs of the Picual, Arbequina, Taggiasca, and Colombaia cultivars were obtained from industrial oil mills. EVOOs were stored under dark, in closed-bottles (10% head-space), at 25-40ºC for a period of 8 months. For each cultivar six bottles were taken from the incubator at scheduled times (monthly) for the analysis of acidity, peroxide number, spectroscopic indices K232 and K270, alpha-tocopherol, phenolics, and antioxidant activity (2).
Results. Four monovarietal EVOOs with different fatty acid compositions and antioxidant contents were chosen to define the extent of antioxidant degradation during storage. Secoiridoids, alpha-tocopherol, and the antioxidant activity decreased in all EVOOs following pseudo-first order kinetics. Oleuropein derivatives were less stable than the corresponding ligstroside derivatives and alpha-tocopherol. Hydroxytyrosol and tyrosol increased during storage as a result of secoiridoid hydrolysis. However, the increase of simple phenolics was lower than the decrease of their precursors, indicating that degradation occurred via both hydrolysis and oxidation. Free acidity, peroxide value, and the spectroscopic indices in the UV region increased following pseudo-zero order kinetics.
The rate constants for quality indices degradation were obtained, and the time to reach the limits established by EU Regulation was calculated. In all EVOOs K232 was the first parameter that exceeded the legal limit. It was found that when EVOOs attained the this latter threshold the residual antioxidant activity was more than 60% with respect to the initial value. These data led to the conclusion that the beneficial properties of EVOOs due to antioxidant activity can be maintained throughout their commercial lives.
References
1. V. Lavelli (2002) J Agric. Food Chem. 50, 26, 7704-7708.
2. V. Lavelli, G. Fregapane, M.D. Salvador (2006), J Agric. Food Chem. 54, 8, 3002-3007
Kinetics of quality degradation during storage of monovarietal extra virgin olive oils
Introduction. Lipophilic derivatives of olive secoiridois (namely, the dialdehydic form of decarboxymethyl oleuropein aglycone, the isomer of oleuropein aglycone, the dialdehydic form of decarboxymethyl ligstroside aglycone, and the isomer of ligstroside aglycone) are present in extra virgin olive oil (EVOO) due to the hydrolysis of their glycosidic precursor catalysed by endogenous glycosidases during the crushing of olive fruit. These compounds as well as alpha-tocopherol have received considerable interest due to their potential health effects, and could be used as indices to evaluate EVOO quality in addition to those established by the EU Regulations (1). Here we report on the kinetics of autoxidation and hydrolytic processes that occur during storage of EVOO, and their effects on the antioxidant content. The aim of this study was to determine whether the potential properties of EVOO antioxidants are maintained or lost during the commercial life of the product.
Materials and methods. EVOOs of the Picual, Arbequina, Taggiasca, and Colombaia cultivars were obtained from industrial oil mills. EVOOs were stored under dark, in closed-bottles (10% head-space), at 25-40ºC for a period of 8 months. For each cultivar six bottles were taken from the incubator at scheduled times (monthly) for the analysis of acidity, peroxide number, spectroscopic indices K232 and K270, alpha-tocopherol, phenolics, and antioxidant activity (2).
Results. Four monovarietal EVOOs with different fatty acid compositions and antioxidant contents were chosen to define the extent of antioxidant degradation during storage. Secoiridoids, alpha-tocopherol, and the antioxidant activity decreased in all EVOOs following pseudo-first order kinetics. Oleuropein derivatives were less stable than the corresponding ligstroside derivatives and alpha-tocopherol. Hydroxytyrosol and tyrosol increased during storage as a result of secoiridoid hydrolysis. However, the increase of simple phenolics was lower than the decrease of their precursors, indicating that degradation occurred via both hydrolysis and oxidation. Free acidity, peroxide value, and the spectroscopic indices in the UV region increased following pseudo-zero order kinetics.
The rate constants for quality indices degradation were obtained, and the time to reach the limits established by EU Regulation was calculated. In all EVOOs K232 was the first parameter that exceeded the legal limit. It was found that when EVOOs attained the this latter threshold the residual antioxidant activity was more than 60% with respect to the initial value. These data led to the conclusion that the beneficial properties of EVOOs due to antioxidant activity can be maintained throughout their commercial lives.
References
1. V. Lavelli (2002) J Agric. Food Chem. 50, 26, 7704-7708.
2. V. Lavelli, G. Fregapane, M.D. Salvador (2006), J Agric. Food Chem. 54, 8, 3002-3007
Relationship Between Sensory Evaluation Performed by Italian and Spanish Official Panels and Volatile and Phenolic Profiles of Virgin Olive Oils
Virgin olive oil (VOO) is typified by characteristic, pleasant sensory notes that differentiate it from other edible oils. Sensory taste, together with nutritional aspects, is the main reason for the increase in consumption of VOO in recent years. Sensory analysis is required by European Official Regulations for olive oil in order to classify the product in commercial categories. In this study, the
relationship between sensory and chemical composition has been investigated. In particular, 16 VOO samples (15 from a single variety of olives), produced in Italy and Spain (eight from each country), were analyzed. Sensory attributes were valued by four panels (three officially recognized both by IOOC and National Ministry: two Italian and two Spanish) employing a total of 59 tasters. Volatile and phenolic compounds were related to olfactory and gustative notes, respectively. Volatile compounds were then separated, identified, and quantified, starting from oil samples, by
solid phase microextraction and capillary gas chromatographic
analysis using a mass spectrometry detector (SPME/cGC-MSD). Furthermore, the phenolic profile was examined by high-performance liquid chromatography with diode-array and mass spectrometry detectors (HPLC-DAD/MSD). Correlations were found between the major volatile compounds (sum of aldehydes C6) and orthonasal perception of olive fruity and retronasal odor of almond.
Additional correlations with bitterness and pungency were
observed for tyrosol and oleuropein aglycon, respectively
Retention effects of oxidized polyphenols during analytical extraction of phenolic compounds of virgin olive oil
The hydrophilic extract of virgin olive oil contains several phenolic compounds such as simple phenols, lignans, and secoiridoids that have been widely studied in recent years. Interest in the hydrophilic extract has also been extended to the fraction
of oxidized phenols that form during storage as a consequence of oxidative stress. The present investigation compares the two most commonly used extraction methods, namely liquid–liquid extraction and SPE, on fresh virgin olive oil and that kept at different temperatures in the presence of oxygen to promote the formation
of oxidative products. The selective retention of these natural and oxidized phenolic compounds in relation to the extraction method was assessed. Quantification of eight identified phenolic molecules and 11 unknown peaks was performed by HPLC-DAD/MSD