The role of wine polysaccharides on salivary protein-tannin interaction: A molecular approach

Natural Tannin Wood Extracts as a Potential Food Ingredient in the Food Industry

Wood extracts are one of the most important natural sources of industrially obtained tannins. Their use in the food industry could be one of the biggest (most important) recent innovations in food science as a result of their multiple (many) possible applications. The use of tannin wood extracts (TWEs) as additives directly added in foods or in their packaging meets an ever-increasing consumer demand for innovative approaches to sustainability. The latest research is focusing on new ways to include them directly in food, to take advantage of their specific actions to prevent individual pathological conditions. The present review begins with the biology of TWEs and then explores their chemistry, specific sensorial properties, and current application in food production. Moreover, this review is intended to cover recent studies dealing with the potential use of TWEs as a starting point for novel food ingredients.

Inhibition Mechanisms of Wine Polysaccharides on Salivary Protein Precipitation

In this work, high-performance liquid chromatography, fluorescence quenching, nephelometry, and sodium dodecyl sulfate polyacrylamide gel electrophoresis were used to study the effect of polysaccharides naturally present in wine [rhamnogalacturonan II (RG II) and arabinogalactan proteins (AGPs)] on the interaction between salivary proteins (SP) together present in saliva and tannins (punicalagin (PNG) and procyanidin B2). In general, the RG II fraction was more efficient to inhibit SP precipitation by tannins, especially for acidic proline-rich proteins (aPRPs) and statherin/P-B peptide, than AGPs. The RG II fraction can act mainly by a competition mechanism in which polysaccharides compete by tannin binding. However, in the presence of Na⁺ ions in solution, no RG II effect was observed on SP-tannin interactions. On the other hand, dependent upon the saliva sample as well as the tannin studied, AGPs can act by both mechanisms, competition and ternary (formation of a ternary complex with SP-tannin aggregates enhancing their solubility).

Number of galloyl moieties and molecular flexibility are both important in alpha-amylase inhibition by galloyl-based polyphenols

The inhibition of porcine pancreatic α-amylase (PPA) by 9 galloyl-based polyphenols was evaluatedviainitial digestion velocity, IC₅₀, inhibition kinetics, fluorescence quenching and molecular docking studies.

RECENT ADVANCES IN STUDYING TANNIC ACID AND ITS INTERACTION WITH PROTEINS AND POLYSACCHARIDES

The purpose of this review was to gain a deeper understanding of tannic acid (TA) and its properties, which could be important for improving the technology of gluten-free food. TA is widely used in agriculture, food, medicine, and other fields due to its unique physiological functions (anti-tumor, anti-oxidation, antibacterial, anti-viral, etc.). It can closely interact with proteins and polysaccharides, which can significantly influence the structure, function, and nutritional properties of compounds. In this article, TA is chosen as a polyphenol model, and the structure of tannins and the degree of their extraction have been considered systematically. Prospective application of interaction between TA and common biological macromolecules have been presented. In this review, different classes of tannins are summarized. Advantages and disadvantages of different methods of extracting tannins have also been described. This review provides detailed information about the mechanisms of interaction of TA with biological macromolecules such as proteins and polysaccharides. Maize, buckwheat, rice flour and starch should be introduced as non-traditional raw materials in production of pasta for people ill with coeliac disease. Pasta dough from unconventional raw materials has non-standard rheological characteristics, and it is difficult to impart good plastic properties to it. That is why, studying the properties of tannins is necessary to improve the technology of gluten-free pasta. However, due to the different nature and composition of proteins, gluten-free foods do not have a network structure. So, they can hold neither water nor starch granules, their prepared dough is loose, with low viscosity, and is not easily moulded. That is why, the use of tannin to form a strong structure when developing a gluten-free pasta technology has become the main purpose of the research. Some potential problems of gluten-free dough processing can be solved by using new technical means. In view of this, the authors put forward the idea of using TА to form cross-links and a strong gluten-free dough structure.

Tracking polysaccharides during white winemaking using glycan microarrays reveals glycoprotein-rich sediments

Winemaking results in a significant amount of sediments that are formed in the tanks, the vats and in the bottles before and after fermentation. Little is known about the biochemical composition of these sediments apart from the fact that they are assumed to be derived in large part from the grape matrix. Glycan microarray technology offers a relatively rapid means to track the polysaccharides from their origin in the grape material and throughout the various steps in the winemaking process. In this study Comprehensive Microarray Polymer Profiling (CoMPP) was used to investigate the glycan-rich composition of particularly white grapes during winemaking and then investigate the effects of recombinant and commercial enzyme formulations on wine sediment compositions. The gross lees or sediments produced in the absence of enzymes were found to be composed of an abundance of homogalacturonans, rhamnogalacturonans, arabinans and galactans in addition to an abundance of extensins and arabinogalactan proteins. The addition of enzymes was shown to strip off the homogalacturonan and much of the rhamnogalacturonan with its side chains revealing a sediment layer composed almost exclusively of extensins and arabinogalactan proteins. The effect of winemaking techniques was shown to have an effect on the glycan-rich wine sediment compositions and holds implications for the management of gross lees in a winery environment.

Applying Nanoparticle Tracking Analysis to Characterize the Polydispersity of Aggregates Resulting from Tannin-Polysaccharide Interactions in Wine-Like Media

Interactions between grape seed tannin and either a mannoprotein or an arabinogalactan in model wine solutions of different ethanol concentrations were characterized with nanoparticle tracking analysis (NTA), UV-visible spectroscopy and dynamic light scattering (DLS). NTA results reflected a shift in particle size distribution due to aggregation. Furthermore, the light scattering intensity of each tracked particle measured by NTA demonstrated the presence of aggregates, even when a shift in particle size was not apparent. Mannoprotein and arabinogalactan behaved differently when combined with seed tannin. Mannoprotein formed large, highly light-scattering aggregates, while arabinogalactan exhibited only weak interactions with seed tannin. A 3% difference in alcohol concentration of the model solution (12 vs. 15% v/v) was sufficient to affect the interactions between mannoprotein and tannin when the tannin concentration was high. In summary, this study showed that NTA is a promising tool for measuring polydisperse samples of grape and wine macromolecules, and their aggregates under wine-like conditions. The implications for wine colloidal properties are discussed based on these results.

A Novel Method for the Quantification of White Wine Mannoproteins by a Competitive Indirect Enzyme-Linked Lectin Sorbent Assay (CI-ELLSA)

Mannoproteins (MPs) are cell wall proteoglycans released in wine by yeast during fermentation and ageing on lees, a procedure used for the production of several wines to enrich them in these components with consequences from both a technological and sensory point of view. Given the significance that wine MPs have for wine quality, winemakers would welcome a simple and accurate method for their quantification, as this would allow them to have a better control of this aspect at different winemaking stages. This study develops and validates a novel, simple and accurate method for MPs quantification in white wines based on a competitive indirect enzyme-linked lectin sorbent assay (CI-ELLSA), using the highly mannosylated yeast invertase as the standard. The method utilizes the lectin concanavalin A (ConA) as the immobilized ligand for MPs, and peroxidase, an enzyme rich in mannose, as the competitor for ConA. After addition of the peroxidase substrate, the intensity of the signal produced by the activity of this enzyme (absorbance at 450 nm) is inversely proportional to the amount of mannosylated proteins in the sample. Results have been validated on several wine styles including still, sparkling and sweet wines.

Effect of the addition of mannoproteins on the interaction between wine flavonols and salivary proteins

It has been suggested that the addition of flavonols (i.e. white grape skins) improves and stabilizes the color of red wines. However, it has been shown that flavonol glycosides produce a mouth-drying and mouth-coating sensation at very low threshold concentrations. Moreover, the addition of polysaccharides to wines is a practice addressed to improve the smoothness and roundness and correct excessive astringency, so we have studied the effect of the addition of yeast mannoproteins (MP) on the interaction between quercetin 3-glucoside and human salivary peptides. Sensory analysis showed the first evidence of the mannoprotein smoothing effect when the flavonol is added to wine. Additionally, MP/SP/polyphenol interactions were studied using fluorescence spectroscopy, dynamic light scattering and isothermal titration calorimetry. Results obtained indicate not only the existence of interactions between mannoproteins and flavonols but also between mannoproteins and salivary proteins (SP), suggesting a possible formation of protein/polyphenol/polysaccharide ternary complex.

Interactions between wine phenolic compounds and human saliva in astringency perception

Astringency is a complex perceptual phenomenon involving several sensations that are perceived simultaneously. The mechanism leading to these sensations has been thoroughly and controversially discussed in the literature and it is still not well understood since there are many contributing factors. Although we are still far from elucidating the mechanisms whereby astringency develops, the interaction between phenolic compounds and proteins (from saliva, oral mucosa or cells) seems to be most important. This review summarizes the recent trends in the protein-phenol interaction, focusing on the effect of the structure of the phenolic compound on the interaction with salivary proteins and on methodologies based on these interactions to determine astringency.