Nuclear magnetic resonance applications in fermented foods and plant-based beverages: challenges and opportunities

Currently, there has been a growing interest in fermented foods and plant-based beverages (PBBs) by the consumers because of the benefits they provide to human health or due to restrictions in the diet associated to some pathologies or personal choices. Nuclear magnetic resonance (NMR) is a versatile technique that presents many advantages for the identification and quantification of metabolites in food with a variety of one- and two-dimensional experiments. This review delves into the current applications of NMR in the fields of fermented foods and PBBs. The interest from researchers in the analysis of fermented foods by NMR in the recent literature mainly focused on three main sub-areas: characterization of exopolysaccharides (EPS) and their functional, and rheological properties; metabolomics to find discriminant markers during and after the process of fermentation for the optimization of the productive process or development of products; and characterization of traditional and novel foods. However, the area of plant-based beverages studies by NMR presented a remarkable literature gap. The opportunities for future investigations concerning food authentication, traceability, and functional food development, among others, are presented

Changes in the contents of micro- and trace-elements in wine due to winemaking treatments

Forty-four mineral elements quantified by ICP-OES and ICP-MS were measured in wines, (a) after wine fining, at three pH levels with 10 different bentonites (1 g·l-1), (b) after addition of yeast hulls from 2 suppliers to wine (180 and 360 mg·1-1). Bentonite fining resulted in statistically significant increases of the large majority of elements, but in significant lower levels of Cu, K, Rb and Zn. The addition of yeast hulls caused a statistically significant depletion of the contents of Ce, Cu, Fe, La, Sb, U, V and Y.

Molecular docking simulations on histone deacetylases (Hdac)-1 and-2 to investigate the flavone binding

Histone modifications through acetylation are fundamental for remodelling chromatin and consequently activating gene expression. The imbalance between acetylation and deacetylation activity causes transcriptional dysregulation associated with several disorders. Flavones, small molecules of plant origin, are known to interfere with class I histone deacetylase (HDAC) enzymes and to enhance acetylation, restoring cell homeostasis. To investigate the possible physical interactions of flavones on human HDAC1 and 2, we carried out in silico molecular docking simulations. Our data have revealed how flavone, and other two flavones previously investigated, i.e., apigenin and luteolin, can interact as ligands with HDAC1 and 2 at the active site binding pocket. Regulation of HDAC activity by dietary flavones could have important implications in developing epigenetic therapy to regulate the cell gene expression

Online Learning From Input Versus Offline Memory Evolution in Adult Word Learning: Effects of Neighborhood Density and Phonologically Related Practice

This is the author's accepted manuscript. The original publication is available at http://jslhr.pubs.asha.org/article.aspx?articleid=1851189Purpose. This study investigates adult word learning to determine how neighborhood density and practice across phonologically-related training sets influence on-line learning from input during training versus off-line memory evolution during no-training gaps. Method. Sixty-one adults were randomly assigned to learn low or high density nonwords. Within each density condition, participants were trained on one set of words and then were trained on a second set of words, consisting of phonological neighbors of the first set. Learning was measured in a picture-naming test. Data were analyzed using multilevel modeling and spline regression. Results. Steep learning during input was observed, with new words from dense neighborhoods and new words that were neighbors of recently learned words (i.e., second set words) being learned better than other words. In terms of memory evolution, large and significant forgetting was observed during 1-week gaps in training. Effects of density and practice during memory evolution were opposite of those during input. Specifically, forgetting was greater for high density and second set words than for low density and first set words. Conclusion. High phonological similarity, regardless of source (i.e., known words or recent training), appears to facilitate on-line learning from input but seems to impede off-line memory evolution

NMR profiling of grape musts from some Italian regions

With wine fraud, being a widespread problem [1], the need for more sophisticated and precise analytical methods of its detection remains ever persistent. Nuclear magnetic resonance (NMR) spectroscopy has been widely used for analysis of wine in recent years [2,3], but wine musts were much less studied; in fact, only one paper dealt with the NMR spectra of actual musts [4]. Difficulties arise mostly because grape musts are “live” objects, which undergo rapid fermentation at room temperature, if not inhibited either by freezing or chemical preservative; but even such measures are not sufficient to halt it completely [5]. We have investigated over 300 samples of grape must from 17 of 20 different Italian regions using 1H NMR spectroscopy with water signal suppression, postprocessing in the MatLab software with dynamic alignment [6] and optimized binning [7] to alleviate the effect of fermentation on the chemical shifts of mobile protons. After that, multivariate statistics was performed with techniques such as PCA, PLS-DA and OPLS-DA with respect to various group parameters such as regions, vitivinicultural zones, harvest periods and grape varieties. Advantages and drawbacks of each method were addresse

1H NMR profiling and chemometric analysis for ripening and production characterization of Grana Padano cheese

Grana Padano (GP) cheese is a renowned PDO Italian cheese whose nutritional characteristics and market price are influenced by the ripening stage. In this work, it was demonstrated that the combined use of untargeted 1H NMR profiling and chemometric analysis can be used as a powerful tool to quantitatively characterize GP ripening and production, focusing on both aqueous and lipid fractions. An initial exploratory analysis revealed substantial variations in the aqueous fraction attributable to aging time, year and season of production. Multivariate analysis was adopted to show these differences, mainly attributable to amino acids. In contrast, the lipid fraction analysis highlighted the impact of production season on fatty acid unsaturation, influenced by feed variations. As regards the production process, this study focuses on the variations induced by bactofugation. In this respect, the aqueous fraction was found to be extensively influenced by this centrifugation step, affecting compounds crucial to organoleptic characteristic

Isotope ratio mass spectrometry (IRMS) methods for distinguishing organic from conventional food products: a review

The use of isotopic analytical methods for food authentication was established years ago. Changes in food technology and consumer behavior, as well as the increasing number of cases of food fraud, necessitate ongoing research for reliable analytical authentication techniques. This literature review examines recent applications of stable isotope ratio analysis that can be used in cases of organic food mislabeling. Different isotope ratio mass spectrometry (IRMS) techniques are described in this article, including bulk IRMS analysis and the combination of IRMS with novel sample preparation and compound extraction techniques. Compound-specific IRMS analysis comprising mainly hyphenated techniques, such as gas chromatography GC-IRMS, was also considered, and was found to frequently overcome the limitations exhibited by bulk analysis. A wide range of food product categories were covered, including cereals, vegetables, fruit, animal products, and seafood, while the importance of statistical analysis was underlined in determining which stable isotopic compositions (δ(15N), δ(34S), δ(18O), δ(13C), or δ(2H)) could be used as reliable organic authenticity marker

1H-NMR approach for the discrimination of PDO Grana Padano cheese from non-PDO cheeses

Protected Designation of Origin cheeses are products with high-quality standards that can claim higher prices on the market. For this reason, non-PDO cheeses with lower quality can be mislabeled as PDO or mixed with it for economic gain especially when the product is in a shredded form. Luckily, the production of PDO cheese is subjected to strict procedural specification rules that result in a product with a defined profile of its metabolites, which can be used for authentication purposes. In this study, an NMR metabolomic approach combined with multivariate analysis was implemented to build a classification model able to discriminate PDO Grana Padano cheese from a large dataset of competitors. The great advantage of the proposed approach is a simple sample preparation, obtaining a holistic overview of the analyzed samples. The untargeted approach highlighted a “typical profile” of Grana Padano samples, which could be used for protection purposes. In parallel, the targeted results allowed us to identify potential chemicals, such as lactate, some amino acids and lipids. These initial results could open the road to a potential new additional tool to check the authenticity of PDO cheeses in the futur