Food proteins and peptides

The qualitative and quantitative determination of proteins and peptides in raw or processed food is experiencing a growing interest and importance from both scientific and economic point of view. Proteomics and peptidomics are relatively new entries in the field of food security, safety and authenticity, and themselves can contribute to the emergence of new branches of the science of food, such as foodomics and the just born nutriomics, digestomics, and gut metagenomics/metaproteomics. Mass spectrometry, in combination with a wide variety of separation methods and bioinformatic tools, is the principal methodology for proteomics. Both the so-called "in-gel" and "gel-free shotgun" bottom-up approaches are widely used.Among the arguments described in this chapter there are: stress effects on gene expression, postharvest (plant) and postmortem (livestock) protein modification, food safety, quality and authentication, food processing and quality control, frauds discovery, food peptidomics and digestomics. © 2015 Elsevier B.V

Liquid chromatographic strategies for separation of bioactive compounds in food matrices

Nowadays, there is an increasing attention for nutraceuticals and, in general, bioactive compounds naturally present in food. Indeed, the possibility of preserving human health and preventing disease (e.g., cardiovascular diseases, cancer etc.) by the intake of healthy food is attractive for both consumers and food industries. In turn, research in this field was also prompted significantly, with the aim of characterizing these bioactive compounds and ascribe to them a specific activity. The bioactive compounds can belong to several chemical classes. However, their chemical diversity and presence in complex matrices, such as food, make it challenging both their isolation and characterization. To tackle this issue, efficient separation systems are needed, which are mainly based on chromatography. In this context, this mini-review aims to provide the reader with an overview of the most relevant and recent approaches for the separation of the most common bioactive compounds in food, in particular polyphenols, phenols, carotenoids, and peptides, by liquid chromatography approaches. © 2018 by the authors

Development of a rapid LC-MS/MS Method for the determination of emerging fusarium mycotoxins enniatins and beauvericin in human biological fluids

A novel method for the simultaneous determination of enniatins A, A1, B and B1 and beauvericin, both in human urine and plasma samples, was developed and validated. The method consisted of a simple and easy pretreatment, specific for each matrix, followed by solid phase extraction (SPE) and detection by high performance liquid chromatography-tandem mass spectrometry with an electrospray ion source. The optimized SPE method was performed on graphitized carbon black cartridges after suitable dilution of the extracts, which allowed high mycotoxin absolute recoveries (76%-103%) and the removal of the major interferences from the matrix. The method was extensively evaluated for plasma and urine samples separately, providing satisfactory results in terms of linearity (R² of 0.991-0.999), process efficiency (>81%), trueness (recoveries between 85% and 120%), intra-day precision (relative standard deviation, RSD < 18%), inter-day precision (RSD < 21%) and method quantification limits (ranging between 20 ng·L(-)¹ and 40 ng·L(-)¹ in plasma and between 5 ng·L(-)¹ and 20 ng·L(-)¹ in urine). Finally, the highly sensitive validated method was applied to some urine and plasma samples from different donors

A rapid magnetic solid phase extraction method followed by liquid chromatography-tandem mass spectrometry analysis for the determination of mycotoxins in cereals

Mycotoxins can contaminate various food commodities, including cereals. Moreover, mycotoxins of different classes can co-contaminate food, increasing human health risk. Several analytical methods have been published in the literature dealing with mycotoxins determination in cereals. Nevertheless, in the present work, the aim was to propose an easy and effective system for the extraction of six of the main mycotoxins from corn meal and durum wheat flour, i.e., the main four aflatoxins, ochratoxin A, and the mycoestrogen zearalenone. The developed method exploited magnetic solid phase extraction (SPE), a technique that is attracting an increasing interest as an alternative to classical SPE. Therefore, the use of magnetic graphitized carbon black as a suitable extracting material was tested. The same magnetic material proved to be effective in the extraction of mycoestrogens from milk, but has never been applied to complex matrices as cereals. Ultra high-performance liquid chromatography tandem mass spectrometry was used for detection. Recoveries were &gt; 60% in both cereals, even if the matrix effects were not negligible. The limits of quantification of the method results were comparable to those obtained by other two magnetic SPE-based methods applied to cereals, which were limited to one or two mycotoxins, whereas in this work the investigated mycotoxins belonged to three different chemical classes

Stochastic Gradient Descent-like relaxation is equivalent to Glauber dynamics in discrete optimization and inference problems

Is Stochastic Gradient Descent (SGD) substantially different from Glauber dynamics? This is a fundamental question at the time of understanding the most used training algorithm in the field of Machine Learning, but it received no answer until now. Here we show that in discrete optimization and inference problems, the dynamics of an SGD-like algorithm resemble very closely that of Metropolis Monte Carlo with a properly chosen temperature, which depends on the mini-batch size. This quantitative matching holds both at equilibrium and in the out-of-equilibrium regime, despite the two algorithms having fundamental differences (e.g.\ SGD does not satisfy detailed balance). Such equivalence allows us to use results about performances and limits of Monte Carlo algorithms to optimize the mini-batch size in the SGD-like algorithm and make it efficient at recovering the signal in hard inference problems.Comment: 14 pages, 5 figure

New Magnetic Graphitized Carbon Black TiO2 Composite for Phosphopeptide Selective Enrichment in Shotgun Phosphoproteomics

Graphitized carbon black (GCB) has been employed for extraction of several classes of analytes, due to the large surface area and the unique chemistry of its surface groups that allows for extracting a wide range of analytes, including polar, acidic compounds. Despite the fact that structurally related materials, such as graphene, found application as hybrid-components in phosphoproteomics, surprisingly, GCB has never been used for the selective enrichment of phosphopeptides. For this purpose, in the present work we used GCB to prepare a magnetic composite with TiO2 (mGCB@TiO2) that was then applied to yeast total extracts. We exploited the high surface area provided by nanostructures, the presence of nano-TiO2 for selective binding of phosphopeptides, and the magnetic responsiveness of magnetite for solid-phase separation. The material was extensively characterized at each modification step by transmission electron microscopy, Fourier-transformed infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, and porosimetry. Next, the new system was applied for the enrichment of casein phosphopeptides from a simulated tryptic digest with bovine serum albumin (BSA:casein, 100:1). Finally, after assessing the potential applicability, the composite was employed for enriching phosphopeptides from yeast protein digests. This allowed us not only to optimize the enrichment protocol but also to fully compare its performance to commercial TiO2 spin columns. To achieve this aim, the optimized enrichment protocol was included in a typical shotgun proteomics analytical workflow based on nanoHPLC-MS/MS analysis

Inequalities in maternal health and pregnancy outcome among Nigerian women migrated to Italy

Among migrant women, unfavourable health conditions and adverse obstetric events are observed more often than in native-born parturients. This observational retrospective study evaluated selected pregnancy outcomes in a Nigerian population giving birth at the University Hospital of Verona. Compared to national controls, being Nigerian was associated with preterm birth (aOR 1.6, 95% CI 1.1-2.2) and Cesarean section (aOR 2.2, 95% CI 1.5-2.7). No differences were found in rates of instrumental delivery and the immigrant group had half the risk of genital tears (aOR 0.6, 95% CI 1.1-2.2) with a higher likelihood of undamaged genitals (aOR 1.5, 95% CI 1.3-2.1). Perinatal indicators of neonatal distress were increased among Nigerians, namely a low Apgar score (aOR 2.6, 95% CI 1.4-4.9), NICU admission (aOR 1.7, 95% CI 1.1-2.8), and stillbirth (aOR 4.0, 95% CI 1.3-12.8). In conclusion, sub-Saharan African women of Nigerian origin appeared more vulnerable and exposed to several adverse pregnancy outcomes. These disparities call for the improvement of obstetric care in this immigrant group. Parmis les femmes migrantes, des conditions de santé défavorables et des événements obstétricaux indésirables sont observés plus souvent que chez les parturientes natives. Cette étude rétrospective observationnelle a analysé certaines issues de la grossesse sélectionnées dans une population nigériane accouchant à l'Hôpital Universitaire de Vérone. Par rapport aux témoins nationaux, le fait d'être nigérian était associé à la prématurité (aOR 1.6, 95% CI 1.1-2.2) et à la césarienne (aOR 2.2, 95% CI 1.5-2.7). Aucune différence n'a été trouvée dans les taux d'accouchements instrumentaux et le groupe d'immigrants avait la moitié du risque de déchirures génitales (aOR 0.6, 95% CI 1.1-2.2) avec une probabilité plus élevée d'organes génitaux intacts (aOR 1.5, 95% CI 1.3-2.1). Les indicateurs périnatals de détresse néonatale ont été trouvés augmenté chez les nigérians, à savoir un faible score d'Apgar (aOR 2.6, 95% CI 1.4-4.9), l’admission en soins intensifs néonatals (aOR 1.7, 95% CI 1.1-2.8) et la mortinatalité (aOR 4.0, 95% CI 1.3-12.8). En conclusion, les femmes africaines subsahariennes d'origine nigériane semblaient plus vulnérables et exposées à plusieurs issues défavorables de la grossesse. Ces disparités appellent l'amélioration des soins obstétricaux dans ce groupe d'immigré

Comprehensive identification of native medium-sized and short bioactive peptides in sea bass muscle

Native peptides from sea bass muscle were analyzed by two different approaches: medium-sized peptides by peptidomics analysis, whereas short peptides by suspect screening analysis employing an inclusion list of exact m/z values of all possible amino acid combinations (from 2 up to 4). The method was also extended to common post-translational modifications potentially interesting in food analysis, as well as non-proteolytic aminoacyl derivatives, which are well-known taste-active building blocks in pseudo-peptides. The medium-sized peptides were identified by de novo and combination of de novo and spectra matching to a protein sequence database, with up to 4077 peptides (2725 modified) identified by database search and 2665 peptides (223 modified) identified by de novo only; 102 short peptide sequences were identified (with 12 modified ones), and most of them had multiple reported bioactivities. The method can be extended to any peptide mixture, either endogenous or by protein hydrolysis, from other food matrices. © 2020 Elsevier Lt

High-lard and high-fish-oil diets differ in their effects on function and dynamic behaviour of rat hepatic mitochondria

Background Mitochondria are dynamic organelles that frequently undergo fission and fusion processes, and imbalances in these processes may be involved in obesity and insulin resistance. Aims The present work had the following aims: (a) to evaluate whether the mitochondrial dysfunction present in the hepatic steatosis induced by a high-fat diet is associated with changes in mitochondrial dynamics and morphology; (b) to evaluate whether effects on the above parameters differ between high-lard and high-fish-oil diets, as it has been suggested that fish oil may have anti-obesity and anti-steatotic effects by stimulating fatty acids utilisation. Methods The development of hepatic steatosis and insulin resistance was monitored in rats fed a high-lard or high-fish-oil diet. Immunohistochemical and electronic microscopic observations were performed on liver sections. In isolated liver mitochondria, assessments of fatty acids oxidation rate, proton conductance and oxidative stress (by measuring H2O2 release and aconitase activity) were performed. Western blot and immunohistochemical analyses were performed to evaluate the presence of proteins involved in mitochondrial dynamics (i.e., fusion and fission processes). To investigate the fusion process, mitofusin 2 and autosomal dominant optic atrophy-1 (OPA1) were analysed. To investigate the fission process, the presence of dynamin-related protein 1 (Drp1) and fission 1 protein (Fis1) was assessed. Results High-lard feeding elicited greater hepatic lipid accumulation, insulin resistance with associated mitochondrial dysfunction, greater oxidative stress and a shift towards mitochondrial fission processes (versus high-fish-oil feeding, which had an anti-steatotic effect associated with increased mitochondrial fusion processes). Conclusions Different types of high-fat diets differ in their effect on mitochondrial function and dynamic behaviour, leading to different cellular adaptations to over-feeding

Polyunsaturated Fatty Acids Attenuate Diet Induced Obesity and Insulin Resistance, Modulating Mitochondrial Respiratory Uncoupling in Rat Skeletal Muscle

Omega (ω)-3 polyunsaturated fatty acids (PUFA) are dietary compounds able to attenuate insulin resistance. Anyway, the precise actions of ω-3PUFAs in skeletal muscle are overlooked. We hypothesized that PUFAs, modulating mitochondrial function and efficiency, would ameliorate pro-inflammatory and pro-oxidant signs of nutritionally induced obesity