Search results for "Food analysis."
showing 10 items of 110 documents
The expanding role of LC-MS in analyzing metabolites and degradation products of food contaminants
2008
Abstract Liquid chromatography-mass spectrometry (LC-MS) has contributed significantly in advancing research in the analysis of metabolites and degradation products of food contaminants. Of particular interest is the comprehensive application of LC-MS to discovery of degradation products and metabolites. This review, covering research published between 2003 and 2008, describes how LC-MS has been used in this field, with the majority of work dealing with target-metabolite analysis and only a small fraction using LC-MS comprehensively. In considering the significance of this topic and the potential interest in it, we briefly describe state-of-the art mass analyzers applied for it (QtrAP, QqTO…
Analysis of trichothecenes in laboratory rat feed by gas chromatography-tandem mass spectrometry
2015
A method for the determination of seven trichothecenes, neosolaniol (NEO), diacetoxyscirpenol (DAS), deoxynivalenol (DON), nivalenol (NIV), fusarenon-X (FUS-X), 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON), in laboratory rat feed by GC-MS/MS was developed. Sample extraction and purification was performed by an acidified mixture of acetonitrile/water (80-20% v/v). Limits of quantitation (LOQs) were between 1 and 10 μg kg(-1) for all studied trichothecenes. Eight concentration levels between the LOQ and 100 × LOQ were used for the calibration curves. Matrix-matched calibration was used for quantitation purposes to compensate the detector signal enhancement obtained fo…
Analysis of phytosterols in foods
2006
Phytosterols are bioactive compounds, one of their most studied and outstanding properties being their cholesterol-lowering activity. This explains the growing interest in the phytosterol contents of foods as either intrinsic or added components. The different steps (extraction, saponification, clean up, chromatographic determination) of plant sterol determination are reviewed, and emphasis is placed on the methods used to assay different phytosterols in food.
Influence of brine concentration on swelling pressure of pork meat throughout salting.
2009
Abstract The influence of sodium chloride on the water holding capacity of meat is well known and described in literature. An increase in water holding capacity is associated with an increase in the swelling pressure in the protein matrix. A novel device was used to measure the swelling pressure during brine salting of muscle cylinders (40 × 50 mm), in different NaCl brine concentrations (2.5 to 25%) over 6 days at 4 °C. Changes in meat composition, weight and height of non-constrained control samples were also measured. The aim of this work was to prove the feasibility of using the developed device in order to quantify the influence of the brine concentration on the magnitude of the swelli…
Sample preparation methods for the determination of pesticides in foods using CE-UV/MS.
2010
Much progress has been made in pesticide analysis over the past decade, during this time hyphenated techniques involving highly efficient separation with sensitive detection have become the techniques of choice. Among these, methods based on separation with mass spectrometric detection have resulted in greater likelihood of identification and are acknowledged to be extremely useful and authoritative methods for the determination of pesticide residues but the inherent advantages of the use of CE as a separation technique are well-known and can be summarized as high separation efficiency, low analysis time, high resolution power, and low consumption of samples and reagents. Although UV is the…
The metabolic profile of lemon juice by proton HR-MAS NMR: the case of the PGI Interdonato Lemon of Messina
2015
We have studied by means of High Resolution Magic Angle Spinning Nuclear Magnetic Resonance (HR-MAS NMR) the metabolic profile of the famous Sicilian lemon known as 'Interdonato Lemon of Messina PGI'. The PGI Interdonato Lemon of Messina possesses high organoleptic and healthy properties and is recognised as one of the most nutrient fruits. In particular, some of its constituents are actively studied for their chemo-preventive and therapeutic properties. In this paper, we have determined by means of HR-MAS NMR spectroscopy the molar concentration of the main metabolites constituent the juice of PGI Interdonato Lemon of Messina in comparison with that of the not-PGI Interdonato Lemon of Turk…
Quantification of Listeria monocytogenes in salads by real time quantitative PCR
2005
Abstract A real time quantitative PCR (RTQ-PCR) was carried out purifying DNA extracts of Listeria monocytogenes using a High Pure Listeria Sample Preparation Kit and quantifying in a LightCycler system with hybridisation probes. A standard curve was constructed with serial dilutions. A range linear relationship, from 10 to 10 5 L. monocytogenes colony forming units (CFU), was observed between threshold cycle ( C t ) and logarithmic concentration of the serial dilutions. The assay was linear in a range from 10 to 10 5 L. monocytogenes CFU and the coefficient of determination ( r 2 ) was > 0.98. RTQ-PCR presented an efficiency of > 85%. The accuracy of the PCR-based assay, expressed as % bia…
Real-time quantitative PCR of Staphylococcus aureus and application in restaurant meals.
2006
Staphylococcus aureus is considered the second most common pathogen to cause outbreaks of food poisoning, exceeded only by Campylobacter. Consumption of foods containing this microorganism is often identified as the cause of illness. In this study, a rapid, reliable, and sensitive real-time quantitative PCR was developed and compared with conventional culture methods. Real-time quantitative PCR was carried out by purifying DNA extracts of S. aureus with a Staphylococcus sample preparation kit and quantifying it in the LightCycler system with hybridization probes. The assay was linear from a range of 10 to 10(6) S. aureus cells (r2 > 0.997). The PCR reaction presented an efficiency of >85%. …
Bioaccessibility of bioactive compounds after non-thermal processing of an exotic fruit juice blend sweetened with Stevia rebaudiana
2017
Abstract A comparative study of the bioaccessibility of bioactive compounds and antioxidant capacity in a fruit juice-Stevia rebaudiana mixture processed by pulsed electric fields (PEF), high voltage electrical discharges (HVED) and ultrasound (USN) technology at two equivalent energy inputs (32–256 kJ/kg) was made using an in vitro model. Ascorbic acid was not detected following intestinal digestion, while HVED, PEF and USN treatments increased total carotenoid bioaccessibility. HVED at an energy input of 32 kJ/kg improved bioaccessibility of phenolic compounds (34.2%), anthocyanins (31.0%) and antioxidant capacity (35.8%, 29.1%, 31.9%, for TEAC, ORAC and DPPH assay, respectively) compared…
Direct Peel Monitoring of Xenobiotics in Fruit by Direct Analysis in Real Time Coupled to a Linear Quadrupole Ion Trap–Orbitrap Mass Spectrometer
2013
Study of xenobiotics present in fruit peel by exposing it (without any pretreatment) to direct analysis in real time coupled to a high-resolution orbitrap mass spectrometer (DART-HRMS) is reported for the first time. Variables such as DART gas heater temperature and pressure, source-to-MS distance, and sample velocity are investigated. The analysis of one sample by DART-MS lasts ca. 1 min, and the benefits of both high-resolution and tandem mass spectrometry to elucidate nontarget or unknown compounds are combined. Identification of postharvest fungicides, antioxidants, and sugars in fruit peel is performed in the positive ion mode. A possible elemental formula is suggested for marker compo…