Ανάπτυξη μεθόδων προσδιορισμού και ταυτοποίησης χημικών δεικτών φρεσκότητας τροφίμων με τεχνικές φασματομετρίας μαζών

Στην παρούσα διατριβή μελετήθηκαν οι δείκτες για την εκτίμηση της φρεσκότητας σε τσιπούρες (Sparous aurata) με τη χρήση χρωματογραφίας υδρόφιλων αλληλεπι¬δρά¬σε¬ων (HILIC) και φασματομετρίας μαζών (MS). Έγινε ανασκόπηση των δεικτών που έχουν προταθεί στη βιβλιογραφία για την εκτίμηση της φρεσκότητας στα ψάρια και πραγ-ματοποιήθηκε ανάπτυξη και επικύρωση μεθόδων για τον προσδιορισμό των νουκλεο-τιδίων και των βιογενών αμινών με HILIC και ανιχνευτή ορατού-υπεριώδους και φασματομετρίας μαζών, αντίστοιχα. Η συμπεριφορά των δεικτών μελετήθηκε με την πραγατοποίηση διαφορετικών σεναρίων καταπόνησης από τέσσερις διαφορετικές αλιευτικές περιοχές, το Πόρτο Μπούφαλο- Εύβοια, το Σοφικό – Κόρινθο, την Αργολίδα και τη Μαλεσίνα – Φθιώτιδα. Αρχικά, προσδιορίστηκε η αρχική κατάσταση των δεικτών φρεσκότητας για τα άμεσα αλιευμένα ψάρια (t0). Έπειτα, πραγματοποιήθηκαν τα δύο σενάρια καταπόνησης, ένα στους 0 oC για 16 ημέρες (δειγματοληψία κάθε 4 ημέρες) και το άλλο στους 18 oC για 18 μήνες (δειγματοληψία κάθε 3 μήνες). Τα συμπεράσματα από τα σενάρια καταπόνησης ήταν ότι τα νουκλεοτίδια αποτελούν κατάλληλο δείκτη για τον εντοπισμό βραχυπρόθεσμης αλλοίωσης του ψαριού και από τη μακροπρόθεσμη καταπόνηση ότι ένα ψάρι που καταψύχεται αμέσως διατηρεί σταθερούς τους δείκτες φρεσκότητας σε όλη τη διάρκεια διατήρησής του στην κατάψυξη. Στο τελευταίο μέρος της μελέτης έγινε προσπάθεια να συνδυαστούν τα αποτελέσματα του εργαστηρίου με τη βιομηχανική πρακτική. Πραγματοποιήθηκαν αναλύσεις δειγμά-των, που είχαν αλιευθεί και επεξεργαστεί 0, 6, 12, 24, 36 και 48 ώρες πριν την ψύξη τους και δείγματα για τα οποία ακολουθήθηκε η κανονική βιομηχανική διαδικασία. Η ανάλυση έγινε με δύο τρόπους, σύμφωνα με τις προηγούμενες μεθόδους (στοχευμένη ανάλυση) με φασματομετρία μαζών υψηλής διακριτικής ικανότητας (μη στοχευμένη ανάλυση). Τα αποτελέσματα και των δύο αναλύσεων καταλήγουν στο συμπέρασμα ότι τα δείγματα μεταξύ 0 και 24 ωρών ανήκουν στην ίδια ομάδα, ενώ τα δείγματα της κανονικής βιομηχανικής πρακτικής ανήκουν στην ίδια ομάδα με τα δείγματα των 36 και 48 ωρών.The aim of this thesis is to study the freshness indices in sea bream (Sparous aurata) with hydrophilic interaction liquid chromatography (HILIC) and mass spectrometry detector (MS). The literature about fish freshness indices was reviewed and two methods were developed for the determination of nucleotides and biogenic amines with HILIC and detectors UV-Vis and mass spectrometry, respectively. The indices were studied with two different stress scenarios in four different farm fishing regions, Porto Buffalo- Evia, Sofiko-Korinthos, Argolida, Malesina-Phthiotis. First, it was determined the level of freshness indices in immediately-fished fishes (time point taken as time instance zero). Then, the two scenarios took place and the samples were stored at 0 oC for 16 days (time point every 4 days) and at 18 oC for 18 months (time intervals: 3 months). The conclusions for stress scenarios were that nucleotides are the best freshness indices for the detection of short-term spoilage and an immediately frozen fish is kept stable all indices for the time that it is been stored. In the last part of this thesis the combination of the laboratory results with the industrial practice was examined. In doing so, immediately-fished fishes were processed and frozen in different time points. Time instances chosen were 0, 6, 12, 24, 36, 48 hours after fishing and the results were compared with those obtained with samples that followed the standard industrial procedure. All determinations were performed by the aforementioned methods (targeted analysis) and with high resolution mass spectro¬me-try (untargeted screening). From the results of both analyses, it is concluded that 24 hours after fishing are the crucial time point for the of change of fish freshness

Carotid ultrasound findings as a predictor of long-term survival after abdominal aortic aneurysm repair: a 14-year prospective study

AbstractPurposeSeveral factors have been related to long-term survival after open abdominal aortic aneurysm (AAA) repair. The effect of carotid stenosis on outcome has not yet been examined. We performed an open prospective study to evaluate the prognostic significance of carotid stenosis on long-term survival of patients who had undergone elective operative repair of AAA.MethodsTwo hundred eight patients who underwent elective open AAA repair in our department between March 1987 and December 2001 were included in the study. All patients were evaluated preoperatively with color duplex ultrasound (US) scanning of the carotid arteries, and were followed up with clinical examination and carotid duplex US scanning 1 month after the operation and every 6 months thereafter. Median duration of follow-up was 50 months (range, 5-181 months). Cardiovascular morbidity and mortality, as well as all causes of mortality, were recorded and analyzed with regard to traditional risk factors and carotid US findings.ResultsTwenty-seven fatal and 46 nonfatal cardiovascular events were recorded. Both univariate and multivariate analysis showed that carotid stenosis 50% or greater and echolucent plaque were significantly associated with cardiovascular mortality and morbidity. Carotid stenosis was a stronger predictor of cardiovascular death than was ankle/brachial index. Age, hypercholesterolemia, coronary artery disease, and diabetes mellitus were also associated with higher mortality and morbidity from cardiovascular causes.ConclusionPatients electively operated on for AAA repair and with stenosis 50% or greater and echolucent plaque at duplex US scanning are at significantly increased risk for cardiovascular mortality and morbidity. Carotid US can therefore be used to select a subgroup of patients with AAA who might benefit from medical intervention, including antiplatelet and lipid-lowering agents

Study on the fate of per- and polyfluoroalkyl substances during thermophilic anaerobic digestion of sewage sludge and the role of granular activated carbon addition

publishedVersio

Development of methods for the determination and identification of chemical freshness indices in food with mass spectrometry techniques

The aim of this thesis is to study the freshness indices in sea bream (Sparous aurata) with hydrophilic interaction liquid chromatography (HILIC) and mass spectrometry detector (MS). The literature about fish freshness indices was reviewed and two methods were developed for the determination of nucleotides and biogenic amines with HILIC and detectors UV-Vis and mass spectrometry, respectively. The indices were studied with two different stress scenarios in four different farm fishing regions, Porto Buffalo- Evia, Sofiko-Korinthos, Argolida, Malesina-Phthiotis. First, it was determined the level of freshness indices in immediately-fished fishes (time point taken as time instance zero). Then, the two scenarios took place and the samples were stored at 0 oC for 16 days (time point every 4 days) and at -18 oC for 18 months (time intervals: 3 months). The conclusions for stress scenarios were that nucleotides are the best freshness indices for the detection of short-term spoilage and an immediately frozen fish is kept stable all indices for the time that it is been stored. In the last part of this thesis the combination of the laboratory results with the industrial practice was examined. In doing so, immediately-fished fishes were processed and frozen in different time points. Time instances chosen were 0, 6, 12, 24, 36, 48 hours after fishing and the results were compared with those obtained with samples that followed the standard industrial procedure. All determinations were performed by the aforementioned methods (targeted analysis) and with high resolution mass spectro¬me-try (untargeted screening). From the results of both analyses, it is concluded that 24 hours after fishing are the crucial time point for the of change of fish freshness.Στην παρούσα διατριβή μελετήθηκαν οι δείκτες για την εκτίμηση της φρεσκότητας σε τσιπούρες (Sparous aurata) με τη χρήση χρωματογραφίας υδρόφιλων αλληλεπιδράσεων (HILIC) και φασματομετρίας μαζών (MS). Έγινε ανασκόπηση των δεικτών που έχουν προταθεί στη βιβλιογραφία για την εκτίμηση της φρεσκότητας στα ψάρια και πραγ-ματοποιήθηκε ανάπτυξη και επικύρωση μεθόδων για τον προσδιορισμό των νουκλεο-τιδίων και των βιογενών αμινών με HILIC και ανιχνευτή ορατού-υπεριώδους και φασματομετρίας μαζών, αντίστοιχα. Η συμπεριφορά των δεικτών μελετήθηκε με την πραγατοποίηση διαφορετικών σεναρίων καταπόνησης από τέσσερις διαφορετικές αλιευτικές περιοχές, το Πόρτο Μπούφαλο- Εύβοια, το Σοφικό – Κόρινθο, την Αργολίδα και τη Μαλεσίνα – Φθιώτιδα. Αρχικά, προσδιορίστηκε η αρχική κατάσταση των δεικτών φρεσκότητας για τα άμεσα αλιευμένα ψάρια (t0). Έπειτα, πραγματοποιήθηκαν τα δύο σενάρια καταπόνησης, ένα στους 0 oC για 16 ημέρες (δειγματοληψία κάθε 4 ημέρες) και το άλλο στους -18 oC για 18 μήνες (δειγματοληψία κάθε 3 μήνες). Τα συμπεράσματα από τα σενάρια καταπόνησης ήταν ότι τα νουκλεοτίδια αποτελούν κατάλληλο δείκτη για τον εντοπισμό βραχυπρόθεσμης αλλοίωσης του ψαριού και από τη μακροπρόθεσμη καταπόνηση ότι ένα ψάρι που καταψύχεται αμέσως διατηρεί σταθερούς τους δείκτες φρεσκότητας σε όλη τη διάρκεια διατήρησής του στην κατάψυξη. Στο τελευταίο μέρος της μελέτης έγινε προσπάθεια να συνδυαστούν τα αποτελέσματα του εργαστηρίου με τη βιομηχανική πρακτική. Πραγματοποιήθηκαν αναλύσεις δειγμά-των, που είχαν αλιευθεί και επεξεργαστεί 0, 6, 12, 24, 36 και 48 ώρες πριν την ψύξη τους και δείγματα για τα οποία ακολουθήθηκε η κανονική βιομηχανική διαδικασία. Η ανάλυση έγινε με δύο τρόπους, σύμφωνα με τις προηγούμενες μεθόδους (στοχευμένη ανάλυση) με φασματομετρία μαζών υψηλής διακριτικής ικανότητας (μη στοχευμένη ανάλυση). Τα αποτελέσματα και των δύο αναλύσεων καταλήγουν στο συμπέρασμα ότι τα δείγματα μεταξύ 0 και 24 ωρών ανήκουν στην ίδια ομάδα, ενώ τα δείγματα της κανονικής βιομηχανικής πρακτικής ανήκουν στην ίδια ομάδα με τα δείγματα των 36 και 48 ωρώ

The influence of forest types on manganese content in soils

The concentrations of available and total Mn were determined in the soils of three different forest ecosystems, i.e. a maquis forest, a beech forest and fir one. The concentrations of total Mn in the deeper mineral horizons reflected the type of patent material, but in the surface layers, the more acidic soil (in the beech forest) had the higher concentrations. This was due to the high concentrations of Mn in the standing leaves and litterfall of beech trees, which brought about high litterfall fluxes of Mn in that forest. However, the concentrations of (DTPA) available Mn was significantly higher in the soil under beech only in the 0–10 cm layer, whereas the fast decomposition of organic matter in the Mediterranean zone resulted in higher concentrations of available Mn in the Ofh soil horizon of the maquis plot. The available Mn did not correlate with soil pH. These findings mean that high concentrations of available Mn do not always entail higher uptake. The soil pH played a predominant role for the high concentrations in the vegetation of the beech forest

The influence of forest types on manganese content in soils

The concentrations of available and total Mn were determined in the soils of three different forest ecosystems, i.e. a maquis forest, a beech forest and fir one. The concentrations of total Mn in the deeper mineral horizons reflected the type of patent material, but in the surface layers, the more acidic soil (in the beech forest) had the higher concentrations. This was due to the high concentrations of Mn in the standing leaves and litterfall of beech trees, which brought about high litterfall fluxes of Mn in that forest. However, the concentrations of (DTPA) available Mn was significantly higher in the soil under beech only in the 0–10 cm layer, whereas the fast decomposition of organic matter in the Mediterranean zone resulted in higher concentrations of available Mn in the Ofh soil horizon of the maquis plot. The available Mn did not correlate with soil pH. These findings mean that high concentrations of available Mn do not always entail higher uptake. The soil pH played a predominant role for the high concentrations in the vegetation of the beech forest

The influence of forest types on manganese content in soils

The concentrations of available and total Mn were determined in the soils of three different forest ecosystems, i.e. a maquis forest, a beech forest and fir one. The concentrations of total Mn in the deeper mineral horizons reflected the type of patent material, but in the surface layers, the more acidic soil (in the beech forest) had the higher concentrations. This was due to the high concentrations of Mn in the standing leaves and litterfall of beech trees, which brought about high litterfall fluxes of Mn in that forest. However, the concentrations of (DTPA) available Mn was significantly higher in the soil under beech only in the 0–10 cm layer, whereas the fast decomposition of organic matter in the Mediterranean zone resulted in higher concentrations of available Mn in the Ofh soil horizon of the maquis plot. The available Mn did not correlate with soil pH. These findings mean that high concentrations of available Mn do not always entail higher uptake. The soil pH played a predominant role for the high concentrations in the vegetation of the beech forest

Edible Insects: Benefits and Potential Risk for Consumers and the Food Industry

Proper protein production is a serious challenge for the future. Insects represent an innovative food source and are extremely nutritious, as they have a high content of proteins and a well-balanced nutrient profile. This study focuses on the positive reasons for the use of insects as a food source and examines the contribution of insects to the human diet and the growing demand for cheap proteins in the food industry. In addition, in the present study, analyzes were performed to determine the nutritional value of mealworms and commercially available cricket flour. Moisture, ash, Total Energy Value, proteins, amino acids, fat, fatty acid profiles, carbohydrates, dietary fiber, and minerals were identified. According to the results, the samples have a high protein content and high concentrations of various amino acids (especially the essential amino acids). They also have a well-balanced fatty acid profile, high in polyunsaturated, monounsaturated fatty acids and many minerals. The main tasks are the dissemination of knowledge, the change of the process for obtaining edible insects, the development of the edible insect food industry, the expansion of the composition of already used insects, and the future conduct of research on risks to human health

Monitoring of Aflatoxin M1 in Various Origins Greek Milk Samples Using Liquid Chromatography Tandem Mass Spectrometry

Aflatoxin M1(AFM1), a major metabolite of Aflatoxin B1(AFB1), has been identified as a potential contaminant in dairy products. Because of its possible carcinogenicity, the legislation limits as set by Commission Regulation (EC) No. 1881/2006 are very strict, namely 0.050 μg kg−1 in milk and 0.025 μg kg−1 in infant formulas. To meet these requirements, a sensitive and accurate method was developed, employing liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Ιmmunoaffinity columns (R-Biopharm) were used for sample purification and preconcentration of the analyte of interest. The quantification of AFM1 was conducted using fortified milk samples, while Aflatoxin B2 (AFB2) was used as an internal standard (IS). The method was validated in terms of linearity, precision, trueness, limits of detection and quantification and uncertainty. The performance criteria for the method were evaluated based on European Commission Regulation (EC) No. 401/2006 and its most recent amendment, as well as the suggested criteria for revision by the EU Reference Laboratory for Mycotoxins and Plant Toxins. The recovery was in the range of 77.9–81.0% for all fortification levels (0.025–0.050–0.075 μg kg−1), with RSDR values (Relative Standard Deviation of intermediate precision) ranging from 6.1% to 12%. The method’s detection and quantification limits were 0.0027 μg kg−1 and 0.0089 μg kg−1, respectively. The occurrence of AFM1 was investigated in 40 samples of different animal origin (cow, goat and sheep milk) provided by Greek producers