Improved analysis of grape seed extract by liquid chromatography-high resolution mass spectrometry (LC-HRMS) reveals that proanthocyanidin-protein interaction mechanisms in cream depend on degree of polymerization.

This study aimed to comprehensively characterize chemical profiles of proanthocyanidins (PACs) from grape seed extract (GSE), examine their interactions with proteins in a cream system, and define the mechanisms mediating PAC-protein interactions. GSE PACs were fractionated and characterized by thiolysis followed by liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis. New PACs with a degree of polymerization (DP) up to 16 were identified by improved HRMS data processing methods. In the model cream system, high-DP PACs exhibited greater precipitation capacity and protein binding than low-DP PACs. Low-DP PACs primarily engaged in hydrogen bonding, while high-DP PACs predominantly utilized multiple hydrophobic interaction sites to form cream protein aggregates. Furthermore, particle size and viscosity measurement of cream revealed a progressively DP-dependent increase in aggregated fat globules and cream viscosity. These findings enhanced our understanding of PACs' structural intricacies and highlighted their functional role as PAC-rich natural ingredients in creating structured cream systems.

Aortic dissection: results of the invasive treatment in France between 2012 and 2018 according to the French national database.

BACKGROUND: To evaluate results of the invasive repair in the management of acute aortic dissection (AoD) in France. METHODS: Patients admitted to hospital with acute AoD from 2012 to 2018 were identified. Patient demographics, severity score at admission, treatment strategy and in-hospital mortality were described. For patients undergoing intervention, perioperative complications rate was reported. A secondary analysis evaluating patients' outcome as regards of the annual caseload per center was conducted. RESULTS: Overall, 14,706 patients with acute AoD were identified (male 64%, mean age 67, median modified Elixhauser score 5). The overall incidence increased during the study period (from 3.8 in 2012 to 4.4/100,000 in 2018) associated with a North-South gradient (respectively 3.6 vs. 4.7/100,000) and a winter peak; 45.5% (N.=6697) of patients received medical treatment alone. Among those with invasive repair, 6276 (78.3%) were defined as type A AoD (TAAD), whereas type B AoD (TBAD) accounted for 1733 patients (21.7%), of whom 1632 (94%) had TEVAR and 101 (6%) had other arterial procedures; 30-day mortality was respectively 18.9% in TAAD and 9.5% for TBAD. In high-volume centers (i.e. >20 AoD/year), a lower 3-month mortality of 22.3% was noted compared to 31.4% in the low-volume centres (P<0.001); 47% of patients reported ≥1 early major complication. TEVAR exhibited less complication (P<0.001) compared to other arterial reconstructions in TBAD. CONCLUSIONS: The incidence of acute AoD increased in France over the period of the study and was associated with stable postoperative early mortality. Early postoperative mortality is significantly reduced in high-volume centers.

Moderate heat enhances gliadin-proanthocyanidin interactions.

Understanding wheat gliadin-proanthocyanidin (PA) interactions would be useful to systematically control foams and gels, create novel textures, and reduce inflammatory reactions. This work aimed to determine the effects of heat (50-90 °C) on gliadin-proanthocyanidin (PA) interactions. Gliadin-PA mixtures were heated for 30 min in aqueous ethanol, and resulting morphology, fluorescence, and MW distribution were analyzed. Atomic force microscopy showed that PA greatly increased gliadin particle size, especially with heat. PA significantly quenched gliadin's tryptophan fluorescence. Further fluorescence data analysis indicated that PA interacted with gliadins through static quenching, primarily via hydrophobic interactions, and that 75 °C treatment yielded the greatest gliadin-PA interactions, likely because the proteins unraveled and exposed residues for interaction. PA appeared to interact mostly with ω-gliadins, based on their absence in the SDS-PAGE gel. Though it has been overshadowed in previous studies by non-covalent interactions, staining of quinoproteins indicated that PA covalently cross-linked gliadins at pH âˆ¼ 6.

Impact of condensed tannin interactions with grain proteins and non-starch polysaccharides on batter system properties.

Proanthocyanidins (PA) cross-link wheat gluten proteins and dramatically enhance batter viscosity; PA could similarly affect related grains. This study aimed to determine PA effect on viscosity and pasting properties of barley, rye, and oat flours, and the relative contributions of PA interactions with proteins and non-starch polysaccharides (NSP). PA significantly increased batter viscosity, stability, and RVA peak viscosity in rye and barley flours (2.8× and 1.2×, respectively). Interestingly, viscosity peaked distinctively ~75 °C in PA-treated rye and barley flours, and their isolated protein-starch systems, indicating prolamins unravelled and complexed with PA during heating. Oat was largely unaffected by PA, likely because of its protein composition. Furthermore, water-soluble rye NSP and arabinoxylans, but not barley ß-glucans, significantly increased starch pasting viscosity with PA; oxidative gelation was not a factor. Thus, rye flour viscosity dramatically increased through interactive effects of PA on rye proteins and NSP, which could expand its food applications.

Effects of edible plant polyphenols on gluten protein functionality and potential applications of polyphenol-gluten interactions.

Expanding plant-based protein applications is increasingly popular. Polyphenol interactions with wheat gluten proteins can be exploited to create novel functional foods and food ingredients. Polyphenols are antioxidants, thus generally decrease gluten strength by reducing disulfide cross-linking. Monomeric polyphenols can be used to reduce dough mix time and improve flexibility of the gluten network, including to plasticize gluten films. However, high-molecular-weight polyphenols (tannins) cross-link gluten proteins, thereby increasing protein network density and strength. Tannin-gluten interactions can greatly increase gluten tensile strength in dough matrices, as well as batter viscosity and stability. This could be leveraged to reduce detrimental effects of healthful inclusions, like bran and fiber, to loaf breads and other wheat-based products. Further, the dual functions of tannins as an antioxidant and gluten cross-linker could help restructure gluten proteins and improve the texture of plant-based meat alternatives. Tannin-gluten interactions may also be used to reduce inflammatory effects of gluten experienced by those with gluten allergies and celiac disease. Other potential applications of tannin-gluten interactions include formation of food matrices to reduce starch digestibility; creation of novel biomaterials for edible films or medical second skin type bandages; or targeted distribution of micronutrients in the digestive tract. This review focuses on the effects of polyphenols on wheat gluten functionality and discusses emerging opportunities to employ polyphenol-gluten interactions.

Interaction mechanisms of condensed tannins (proanthocyanidins) with wheat gluten proteins.

Proanthocyanidins (PA) crosslink wheat gluten, increasing its polymer size and strength. However, mechanisms behind these interactions are unknown. This study used PA of different MW profiles (mean degree of polymerization 8.3 and 19.5) to investigate how PA polymerize gluten. The higher MW PA had greater binding affinity for both glutenins and gliadins than lower MW PA, whereas both PA precipitated glutenins more efficiently than gliadins. The PA preferentially bound the largest of the protein fractions available: high MW glutenin subunits (HMW-GS) over low MW-GS, and ω-gliadins over α- and γ-gliadins. Furthermore, within the HMW-GS, PA bound more of the larger x-type than the smaller y-type. Proanthocyanidins reduced gluten solubility in urea and decreased surface hydrophobicity of glutenins, but not gliadins. The PA appear to preferentially crosslink HMW-GS via hydrophobic interactions and hydrogen bonding, whereas their interaction with gliadins is dominated by hydrogen bonding and is relatively weaker.

Effect of Condensed Tannin Profile on Wheat Flour Dough Rheology.

Proanthocyanidins (PA) cross-link proteins and could expand wheat gluten functionality; however, how the PA MW or gluten profile affect these interactions is unknown. Effect of PA MW profile (sorghum versus grape seed PA) on dough rheology of high versus low insoluble polymeric protein (IPP) wheat flour was evaluated using mixograph, large (TA.XT2i) and small (HAAKE Rheostress 6000) deformation rheometry. Sorghum PA (93% polymeric) more effectively (p < 0.05) strengthened both glutens than grape seed PA (45% polymeric), without reducing gluten extensibility. These effects were higher in low IPP (weak gluten) flour, e.g., sorghum PA doubled IPP, increased mix time by 75%, dough elasticity by 82%, and peak angle by 17° versus control. Grape seed PA increased IPP by 75% and elasticity by 36%, but reduced peak angle by 15°, indicating reduced mixing tolerance. Sorghum PA, but not grape seed PA, increased (p < 0.05) all above parameters in high IPP dough. Polymeric PA more effectively strengthened gluten than oligomeric PA, likely via more efficient protein cross-linking to overcome strong antioxidant effect of PA. High MW PA may be useful natural gluten strengtheners for diverse applications.

Interaction of Sorghum Tannins with Wheat Proteins and Effect on in Vitro Starch and Protein Digestibility in a Baked Product Matrix.

Carbohydrates contribute the most dietary calories, which makes starchy foods a logical target for modifying calorie intake. This study investigated the interaction of sorghum bran proanthocyanidins (PA) with proteins during wheat flour tortilla processing and impact on in vitro starch digestibility. Brans from wheat, white (low in phenols), brown (high PA), and black (high monomeric flavonoids) sorghum were used. Changes in phenolic profile, starch, and proteins were evaluated. Dough mixing drastically decreased extractable PA (61-72%) but not monomeric phenolics; higher MW PA decreased the most. The high PA bran dough produced the highest insoluble proteins (460 vs 330 mg/g protein for other sorghum brans) at 25% baker's substitution. The high PA bran tortillas also had higher slow digesting starch and lower rapidly digesting starch than all other bran treatments. Significant sorghum PA-gluten interactions occur during dough mixing that may slow starch digestibility in the baked products.

Imidazolium-based ionic liquid surfaces for biosensing.

Ionic liquid self-assembled monolayers (SAM) were designed and applied for binding streptavidin, promoting affinity biosensing and enzyme activity on gold surfaces of sensors. The synthesis of 1-((+)-biotin)pentanamido)propyl)-3-(12-mercaptododecyl)-imidazolium bromide, a biotinylated ionic liquid (IL-biotin), which self-assembles on gold film, afforded streptavidin sensing with surface plasmon resonance (SPR). The IL-biotin-SAM efficiently formed a full streptavidin monolayer. The synthesis of 1-(carboxymethyl)-3-(mercaptododecyl)-imidazoliumbromide, a carboxylated IL (IL-COOH), was used to immobilize anti-IgG to create an affinity biosensor. The IL-COOH demonstrated efficient detection of IgG in the nanomolar concentration range, similar to the alkylthiols SAM and PEG. In addition, the IL-COOH demonstrated low fouling in crude serum, to a level equivalent to PEG. The IL-COOH was further modified with N,N'-bis (carboxymethyl)-l-lysine hydrate to bind copper ions and then, chelate histidine-tagged biomolecules. Human dihydrofolate reductase (hDHFR) was chelated to the modified IL-COOH. By monitoring enzyme activity in situ on the SPR sensor, it was revealed that the IL-COOH SAM improved the activity of hDHFR by 24% in comparison to classical SAM. Thereby, IL-SAM has been synthesized and successfully applied to three important biosensing schemes, demonstrating the advantages of this new class of monolayers.