Profiling of anthocyanins for the taxonomic assessment of ancient purebred V. vinifera red grape varieties

Turning Wastes into Resources: Red Grape Pomace-Enriched Biscuits with Potential Health-Promoting Properties

The life-long adherence to a dietary pattern able to provide a high amount of polyphenols demonstrating beneficial cardiometabolic effects is demanding for the general population. In this study, red grape pomace (GP) was used as an ingredient to increase the daily polyphenols' intake. The incorporation of crude crushed GP at 20 and 30% (w/w) in a control (CTR) biscuit formula improved the nutritional profile by increasing the fiber and reducing lipid and energy content while providing up to 540 mgGAE of polyphenols per 100 g. Besides anthocyanins, GP contains flavonoids and grape-seed procyanidins, contributing to the remarkable antioxidant capacity of 20- and 30-GP biscuits. Upon in vitro gastro-duodenal enzymatic digestion, the concentration of reducing sugars for 20-GP and 30-GP compared to the CTR biscuits dropped significantly, meaning that the combined action of GP fibers and polyphenols could delay the intestinal absorption of glucose. Overall, 60 volatiles were detected in biscuits. All in all, the content of Maillard reaction products was lower in GP than in CTR biscuits, possibly due to the free radical scavenging ability of polyphenols. Despite the high rates of GP utilized, the sensorial attributes and the overall liking of the GP biscuits-especially the 20-GP ones-were not substantially affected. These findings will support nutritional studies to assess the potential role as functional foods of GP biscuits, and, afterwards, the large-scale production of a food mainly based on a waste ingredient turned into a resource.

Advances in the Chemistry, Analysis and Adulteration of Anthocyanin Rich-Berries and Fruits: 2000-2022

Anthocyanins are reported to exhibit a wide variety of remedial qualities against many human disorders, including antioxidative stress, anti-inflammatory activity, amelioration of cardiovascular diseases, improvement of cognitive decline, and are touted to protect against neurodegenerative disorders. Anthocyanins are water soluble naturally occurring polyphenols containing sugar moiety and are found abundantly in colored fruits/berries. Various chromatographic (HPLC/HPTLC) and spectroscopic (IR, NMR) techniques as standalone or in hyphenated forms such as LC-MS/LC-NMR are routinely used to gauge the chemical composition and ensure the overall quality of anthocyanins in berries, fruits, and finished products. The major emphasis of the current review is to compile and disseminate various analytical methodologies on characterization, quantification, and chemical profiling of the whole array of anthocyanins in berries, and fruits within the last two decades. In addition, the factors affecting the stability of anthocyanins, including pH, light exposure, solvents, metal ions, and the presence of other substances, such as enzymes and proteins, were addressed. Several sources of anthocyanins, including berries and fruit with their botanical identity and respective yields of anthocyanins, were covered. In addition to chemical characterization, economically motivated adulteration of anthocyanin-rich fruits and berries due to increasing consumer demand will also be the subject of discussion. Finally, the health benefits and the medicinal utilities of anthocyanins were briefly discussed. A literature search was performed using electronic databases from PubMed, Science Direct, SciFinder, and Google Scholar, and the search was conducted covering the period from January 2000 to November 2022.

The Luteolinidin and Petunidin 3-O-Glucoside: A Competitive Inhibitor of Tyrosinase

The enzyme tyrosinase plays a key role in the early stages of melanin biosynthesis. This study evaluated the inhibitory activity of anthocyanidin (1) and anthocyanins (2-6) on the catalytic reaction. Of the six derivatives examined, 1-3 showed inhibitory activity with IC₅₀ values of 3.7 ± 0.1, 10.3 ± 1.0, and 41.3 ± 3.2 μM, respectively. Based on enzyme kinetics, 1-3 were confirmed to be competitive inhibitors with K_i values of 2.8, 9.0, and 51.9 μM, respectively. Molecular docking analysis revealed the formation of a binary encounter complex between 1-3 and the tyrosinase catalytic site. Luteolinidin (1) and petunidin 3-O-glucoside (2) may serve as tyrosinase inhibitors to block melanin production.

Differential Protein Expression in Berry Skin from Red Grapes with Varying Hybrid Character

Protein expression from the berry skin of four red grape biotypes with varying hybrid character was compared at a proteome-wide level to identify the metabolic pathways underlying divergent patterns of secondary metabolites. A bottom-up shotgun proteomics approach with label-free quantification and MaxQuant-assisted computational analysis was applied. Red grapes were from (i) purebred Vitis vinifera (Aglianico cv.); (ii) V. vinifera (local Sciascinoso cv.) grafted onto an American rootstock; (iii) interspecific hybrid (V. vinifera × V. labrusca, Isabel), and (iv) uncharacterized grape genotype with hybrid lineage, producing relatively abundant anthocyanidin 3,5-O-diglucosides. Proteomics supported the differences between hybrids and purebred V. vinifera grapes, consistently with distinct phenotypic metabolite assets. Methanol O-anthraniloyltransferase, which catalyses the synthesis of methyl anthranilate, primarily responsible for the “foxy” odour, was exclusive of the Isabel hybrid grape. Most of the proteins with different expression profiles converged into coordinated biosynthetic networks of primary metabolism, while many possible enzymes of secondary metabolism pathways, including 5-glucosyltransferases expected for hybrid grapes, remained unassigned due to incomplete protein annotation for the Vitis genus. Minor differences of protein expression distinguished V. vinifera scion grafted onto American rootstocks from purebred V. vinifera skin grapes, supporting a slight influence of the rootstock on the grape metabolism.

Identification of red grape varieties by anthocyanin profile

The presence of anthocyans was studied to determine the anthocyanin profile as a tool for distinguishing grapes of the Don region of autochthonous and hybrid varieties of ARRIVW breeding and other hybrid varieties for isolation and identifying typical characteristics. The composition of anthocyans depends on both the variety and the grape habitat. The presence of 3.5-diglucosides in hybrid varieties was established.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Characterisation of (poly)phenolic constituents of two interspecific red hybrids of Rondo and Regent (Vitis vinifera) by LC-PDA-ESI-MS QTof

The aim of this study was to identify and compare phenolic acids, flavan-3-ols, flavonols, and anthocyanins in two the most popular interspecific hybrids of red grapes, Rondo and Regent, nowadays very popular in red wine production in Poland. The phenolic profiles of these hybrids have not yet been reported. Thirty-three phenolic compounds, including 2 flavan-3-ols, 3 phenolic acids, 5 flavonols, and 23 anthocyanins, were determined in the examined samples using the ultra-performance liquid chromatography photodiode detector-quadrupole/time of flight-mass spectrometry (UPLC-PDA-Q/TOF-MS) method. Major differences were found in the phenolic profiles of investigated cultivars. The Regent hybrid exhibited the highest total phenolics content (27029.75mg/kg dry matter) but Rondo was characterized by the highest concentration of anthocyanins (19342.36mg/kgdm). The dominant fraction was anthocyanin compounds, especially acetylated>diglucosylated forms than glucosylated ones. This data represents valuable information that may be useful for oenological practices and to valorise these varieties as sources of bioactive compounds.

Inhibitory effect of pomegranate (Punica granatum L.) polyphenol extracts on the bacterial growth and survival of clinical isolates of pathogenic Staphylococcus aureus and Escherichia coli

In the present study major polyphenols of pomegranate arils and peel by-products were extracted in 50% (v/v) aqueous ethanol, characterized and used in microbiological assays in order to test antimicrobial activity against clinically isolated human pathogenic microorganisms. Total concentration of polyphenols and in vitro antioxidant properties were determined by the Folin-Ciocalteu and DPPH methods, respectively. The most abundant bioactive molecules, including anthocyanins, catechins, tannins, gallic and ellagic acids were identified by RP-HPLC-DAD, also coupled to off-line matrix assisted laser desorption/ionization (MALDI-TOF) mass spectrometry (MS). The inhibitory spectrum of extracts against test microorganisms was assessed by the agar well-diffusion method. Data herein indicated that both pomegranate aril and peel extracts have an effective antimicrobial activity, as evidenced by the inhibitory effect on the bacterial growth of two important human pathogens, including Staphylococcus aureus and Escherichia coli, which are often involved in foodborne illness.

Mass spectrometric and enzymatic evidence confirm the existence of anthocyanidin 3,5-O-diglucosides in cabernet sauvignon (Vitis vinifera L.) grape berries

It has been widely accepted that anthocyanidin 3,5-O-diglucosides do not exist in Vitis vinifera L. Cabernet Sauvignon (CS) berries. However, our anthocyanin analyses using HPLC-ESI-MS/MS detected the existence of a low level of anthocyanidin 3,5-O-diglucosides in the Cabernet Sauvignon grape berries grown in China. The authenticity of these samples was confirmed with microsatellite markers. The existence of anthocyanidin 3,5-O-diglucoside was further verified by the enzymatic evidence for the first time. Four putative 5-O-glucosyltransferase (5GT) genes were isolated from the Cabernet Sauvignon berries. The enzymatic analysis showed that a recombinant protein (designated as Vv5GT3) glucosylated the 3-O- and 5-O-positions of anthocyanidins and flavonols. A phylogenetic analysis revealed that this bifunctional enzyme belongs to the 5GT subfamily of UDP-glycosyltransferases. This finding brought a new understanding of the anthocyanins' profile and their biosynthesis in V. vinifera and would be helpful for further investigations of the mechanism of accumulation of anthocyanidin diglucosides in Cabernet Sauvignon berries in China's wine-producing regions.

Antiradical–antimicrobial activity and phenolic profile of pomegranate (Punica granatum L.) juices from different cultivars: a comparative study

Pomegranate juices from the fruits of the two relatively new Greek cultivars “Persephone” and “Porphiroyeneti” were studied compared to the “Wonderful” cultivar.

Multiple loss-of-function 5-O-glucosyltransferase alleles revealed in Vitis vinifera, but not in other Vitis species

Wild and loss-of-function alleles of the 5 - O - glucosyltransferase gene responsible for synthesis of diglucoside anthocyanins in Vitis were characterized. The information aids marker development for tracking this gene in grape breeding. Anthocyanins in red grapes are present in two glycosylation states: monoglucoside (3-O-glucoside) and diglucoside (3, 5-di-O-glucoside). While monoglucoside anthocyanins are present in all pigmented grapes, diglucoside anthocyanins are rarely found in the cultivated grape species Vitis vinifera. Biochemically 3-O-glucoside anthocyanins can be converted into 3,5-di-O-glucoside anthocyanins by a 5-O-glucosyltransferase. In this study, we surveyed allelic variation of the 5-O-glucosyltransferase gene (5GT) in 70 V. vinifera ssp. vinifera cultivars, 52 V. vinifera ssp. sylvestris accessions, 23 Vitis hybrid grapes, and 22 accessions of seven other Vitis species. Eighteen 5GT alleles with apparent loss-of-function mutations, including seven premature stop codon mutations and six frameshift indel mutations, were discovered in V. vinifera, but not in the other Vitis species. A total of 36 5GT alleles without apparent loss-of-function mutations (W-type) were identified. These W-type alleles were predominantly present in wild Vitis species, although a few of them were also found in some V. vinifera accessions. We further evaluated some of these 5GT alleles in producing diglucoside anthocyanins by analyzing the content of diglucoside anthocyanins in a set of representative V. vinifera cultivars. Through haplotype network analysis we revealed that V. vinifera ssp. vinifera and its wild progenitor V. vinifera ssp. sylvestris shared many loss-of-function 5GT alleles and extensive divergence of the 5GT alleles was evident within V. vinifera. This work advances our understanding of the genetic diversity of 5GT and provides a molecular basis for future marker-assisted selection for improving this important wine quality trait.

Analysis of the phenolic composition of fungus-resistant grape varieties cultivated in Italy and Germany using UHPLC-MS/MS

The phenolic composition of grape berries grown in Italy (Cabernet Cortis, Johanniter, Solaris, Phoenix, and Regent) and in Germany (Regent and Phoenix) was analyzed using two complementary LC-MS/MS (Liquid Chromatography - Tandem Quadrupole Mass Spectrometry) methods. These five cultivars belong to fungus-resistant grape varieties (PIWI) and little is known about their phenolic profile, although phenolics such as phytoalexins have been recognized, playing a key role in the resistance mechanism. A triple quadruple mass spectrometer detector was used for both identification and quantification, and analytical tools from untargeted metabolomics were applied to check and control the quality of the results. Specifically, biological, technical, and instrumental replications were included in order to study the variability at different levels. The results allowed tuning of the sampling protocol and provided a rich phenolic metabolite profile for the aforementioned PIWI varieties, as compared with Vitis vinifera cultivars, especially in the class of stilbenes.