1,721,019 research outputs found
Biogenic amines profile and concentration in commercial milks for infants and young children
No full textCommercial milks for infants and young children (CMIYC) received much attention during last years for
their impact on the nutritional status, health and development of the new-born and babies. Among
possible contaminants contained in these foods, biogenic amines (BAs) have rarely been determined
although they can exert toxic effects in humans if ingested at high concentrations. Spermine, spermidine,
putrescine, histamine, tyramine, β-phenylethylamine and cadaverine have been quantified in
CMIYC samples by LC-UV after derivatisation with dansyl-chloride. Once optimised in terms of linearity
(R2 ≥ 0.989), recovery percentages (92.9–97.3), LOD (0.2–0.4 μg g−1 or 0.03–0.05 μgmL−1 depending on
the samples), LOQ (0.5–1.0 μg g−1 and 0.08–0.13 μgmL−1 depending on the samples) and repeatability
(0.1–0.2 intra-day; 0.2–0.4 inter-day), the method has been applied to real samples. Very low total BAs
concentrations have been found in reconstituted (1.18–3.12 mg L−1) and liquid milks (0.33–2.30 mg
L−1), with different biogenic amine profiles and distributions. A risk assessment based on the available
information regarding Acute Reference Doses of histamine and tyramine, as well as the application of
common Biogenic Amine Indexes, showed that none of the analysed samples represented a possible
risk for babies, also considering a worst case evaluation. These findings confirmed the strict safety and
quality protocols adopted during the production of CMIYC
Polyphenols from olive mill wastewaters: large scale sustainability of their recovery, and selective extraction by means of molecularly imprinted polymers
No full textThe use of agroindustrial wastes as potential renewable resources for the production of high added-value compounds, biomolecules or bioenergy has been largely investigated in recent years. To date, integrated multi-step physicochemical biotechnological processes are allowing the extensive valorization of an increasing number of biowastes. In this respect, the design of a biorefinery for the case study of olive mill wastewaters (OMWs) has been recently proposed [1]. Particular attention was given to polyphenols and their recovery through a solid phase extraction procedure. Several commercial adsorbing agents were tested (namely, Amberlite XAD resins, as well as IRA96 and Isolute ENV+). First investigations on their adsorption and desorption capacities were carried out with synthetic solutions made of 10 polyphenols among those commonly found in OMWs, using ethanol as desorbing solvent [2]. Performances of such adsorbing agents were then tested with actual site OMWs [3], showing that Amberlite XAD16 was the most effective, particularly when valuable polyphenols such as hydroxytyrosol and tyrosol were considered. Notwithstanding the fact that solid phase extraction procedure may be very practical, yet proofs of the feasibility of its scale-up have to be shown once the process economy is considered. As a matter of fact, fully activated Amberlite resins may cost some 600 euro per kg, and solvent price may be too high for industrial scale. To this aim, sustained recycling of both the resin and the solvent (i.e., ethanol) was tested [4]. The same amount of Amberlite XAD16 was used in 10 consecutive cycles for polyphenols recovery from actual site OMWs. At the end of each cycle, resin was re-activated using fully biocompatible solutions (i.e., ethanol and water). Sustained reuse of the resin had no negative effects on adsorption capacity, while desorption one was only slightly reduced. Ethanol regeneration was carried out using a rotary evaporator. As a result, Folin Ciocalteu's and HPLC analyses showed no trace of polyphenols in the regenerated ethanol while, notably, the HPLC profile of the concentrated polyphenolic mixture, its anti-radical and antioxidant capacity remained constant. This approach would significantly reduce overall operational costs, and determine a theoretically infinite reuse of the solvent employed. However, if on the one hand intensive recovery of polyphenolic mixtures appears feasible, on the other hand recovery of target molecules from complex substrates appears very difficult yet. In this respect, molecularly imprinted polymers (MIPs) are known to represent a promising solution. First attempts to selective extract and purify a single phenol (i.e., gallic acid, GA) were conducted [5]. Imprinting efficiency was evaluated in different water/ethanol solutions by using pyrogallic acid as the template analogue. When actual site OMWs were employed, recovery values were between 85 and 97%. However, provided that the highest recognition with MIPs usually occurs with pure ethanol, selective recovery of target polyphenols using the concentrated alcoholic mixture as obtained after rotary evaporator is underway
Polyphenols from olive mill wastewaters: large scale sustainability of their recovery, and selective extraction by means of molecularly imprinted polymers
No full textThe use of agroindustrial wastes as potential renewable resources for the production of high added-value compounds, biomolecules or bioenergy has been largely investigated in recent years. To date, integrated multi-step physicochemical biotechnological processes are allowing the extensive valorization of an increasing number of biowastes. In this respect, the design of a biorefinery for the case study of olive mill wastewaters (OMWs) has been recently proposed [1]. Particular attention was given to polyphenols and their recovery through a solid phase extraction procedure. Several commercial adsorbing agents were tested (namely, Amberlite XAD resins, as well as IRA96 and Isolute ENV+). First investigations on their adsorption and desorption capacities were carried out with synthetic solutions made of 10 polyphenols among those commonly found in OMWs, using ethanol as desorbing solvent [2]. Performances of such adsorbing agents were then tested with actual site OMWs [3], showing that Amberlite XAD16 was the most effective, particularly when valuable polyphenols such as hydroxytyrosol and tyrosol were considered. Notwithstanding the fact that solid phase extraction procedure may be very practical, yet proofs of the feasibility of its scale-up have to be shown once the process economy is considered. As a matter of fact, fully activated Amberlite resins may cost some 600 euro per kg, and solvent price may be too high for industrial scale. To this aim, sustained recycling of both the resin and the solvent (i.e., ethanol) was tested [4]. The same amount of Amberlite XAD16 was used in 10 consecutive cycles for polyphenols recovery from actual site OMWs. At the end of each cycle, resin was re-activated using fully biocompatible solutions (i.e., ethanol and water). Sustained reuse of the resin had no negative effects on adsorption capacity, while desorption one was only slightly reduced. Ethanol regeneration was carried out using a rotary evaporator. As a result, Folin Ciocalteu's and HPLC analyses showed no trace of polyphenols in the regenerated ethanol while, notably, the HPLC profile of the concentrated polyphenolic mixture, its anti-radical and antioxidant capacity remained constant. This approach would significantly reduce overall operational costs, and determine a theoretically infinite reuse of the solvent employed. However, if on the one hand intensive recovery of polyphenolic mixtures appears feasible, on the other hand recovery of target molecules from complex substrates appears very difficult yet. In this respect, molecularly imprinted polymers (MIPs) are known to represent a promising solution. First attempts to selective extract and purify a single phenol (i.e., gallic acid, GA) were conducted [5]. Imprinting efficiency was evaluated in different water/ethanol solutions by using pyrogallic acid as the template analogue. When actual site OMWs were employed, recovery values were between 85 and 97%. However, provided that the highest recognition with MIPs usually occurs with pure ethanol, selective recovery of target polyphenols using the concentrated alcoholic mixture as obtained after rotary evaporator is underway
Cambiamenti nel profilo di ammine biogene durante il periodo di conservazione di campioni di bottarga
No full textCambiamenti nel profilo di ammine biogene durante il periodo di conservazione di campioni di bottarg
Carbazole Derivatives: A Promising Scenario for Breast Cancer Treatment
Full text linkChemotherapeutics used in cancer treatment may elicit pleiotropic effects interfering, for instance, directly on DNA metabolism or on endoplasmic organelles functions. Recently there has been a trend towards the use of molecular-targeted therapies as alternative treatments of cancer, arising from the need to overcome the onset of undesired side effects or drug-resistance. Thus, a major challenge is the design and synthesis of new agents able to interact with specific cellular components, often over-expressed or altered in cancerous cells, such as telomerase and topoisomerase or protein kinases, with reduced toxicity at effective doses. The main molecular targets for the development of new anticancer drugs include: cell surface receptors, signal transduction pathways, enzymes, gene transcription, ubiquitin-proteasome/heat shock proteins, and anti-angiogenic agents. Several natural or synthetic polycyclic molecules with carbazolic nucleus, which show attractive drug-like properties, were identified with the aim to increase their biological activities and their specificity, obtaining cytotoxic agents effective in a panel of cancer cell lines. The cytotoxic profile of these compounds has been assessed using several in vitro assays as, for instance, MTT, colony formation, and flow cytometry assays and some of these compounds showed an interesting profile at sub-micromolar concentrations. The usefulness of some carbazole derivatives has been demonstrated, as well, in preclinical studies. - See more at: http://www.eurekaselect.com/132941/article#sthash.sPhGDh36.dpu
Antioxidant Activity of Phenolic Acids: Correlation with Chemical Structure and in Vitro Assays for Analytical Determination
No full textPhenolic acids are a subclass of a larger category of plant metabolites commonly referred to as “phenolics” possessing a carboxylic acid functionality. In general, the term phenolics encompasses approximately 8000 naturally occurring compounds, all of which possess one common structural feature, a phenol (an aromatic ring bearing at least one hydroxyl substituent). The naturally occurring phenolic acids contain two distinguishing constitutive carbon frameworks: the hydroxycinnamic and hydroxybenzoic structures. Although the basic skeleton remains the same, the numbers and positions of the hydroxyl groups on the aromatic ring create the variety. Recent interest in phenolic acids stems from their potential protective role, through ingestion of fruits and vegetables, against oxidative damage diseases due to their antioxidant activity (AOA). This property is related with the ability to scavenge free radicals, donate hydrogen atoms or electron, or chelate metal cations. The molecular structure, referred to as structure–activity relationships SAR (including substituents on the aromatic ring, numbers and positions of the hydroxyl groups in relation to the carboxyl functional group, esterification, glycosylation) affects the antioxidant properties.With the current upsurge of interest in the function, measurement of efficacy and use of natural antioxidants has received much attention. There is a great multiplicity of the methods used for the determination of AOA, which can be broadly classified two groups. In the first group, the degree of inhibition of lipid peroxidation is measured by using lipid or lipoprotein substrate under standard conditions; while in the second the radical scavenging ability is determined. Moreover, a number of assays have been introduced for determining the total antioxidant activity, intended as the cumulative capacity of food compounds to scavenge free radicals. In the discussion, phenolic acids structure as well as SAR will be considered. The various in vitro methods used for the determination of antioxidant activity, with their merits and limitations, will be also presented
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Chemometric analysis for discrimination of extra virgin olive oils from whole and stoned olive pastes
No full textChemometric discrimination of extra virgin olive oils (EVOO) from whole and stoned olive pastes was carried out by using Fourier transform infrared (FTIR) data and partial least squares-discriminant analysis (PLS1-DA) approach. Four Italian commercial EVOO brands, all in both whole and stoned version, were considered in this study. The adopted chemometric methodologies were able to describe the different chemical features in phenolic and volatile compounds contained in the two types of oil by using unspecific IR spectral information. Principal component analysis (PCA) was employed in cluster analysis to capture data patterns and to highlight differences between technological processes and EVOO brands. The PLS1-DA algorithm was used as supervised discriminant analysis to identify the different oil extraction procedures. Discriminant analysis was extended to the evaluation of possible adulteration by addition of aliquots of oil from whole paste to the most valuable oil from stoned olives. The statistical parameters from external validation of all the PLS models were very satisfactory, with low root mean square error of prediction (RMSEP) and relative error (RE%)
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