Plant-derived seasonings as sodium salt replacers in food

A comprehensive review of plant-derived salt substitutes: Classification, mechanism, and application

The diseases caused by excessive sodium intake derived from NaCl consumption have attracted widespread attention worldwide, and many researchers are committed to finding suitable ways to reduce sodium intake during the dietary process. Salt substitute is considered an effective way to reduce sodium intake by replacing all/part of NaCl in food without reducing the saltiness while minimizing the impact on the taste and acceptability of the food. Plant-derived natural ingredients are generally considered safe and reliable, and extensive research has shown that certain plant extracts or specific components are effective salt substitutes, which can also give food additional health benefits. However, these plant-derived salt substitutes (PSS) have not been systematically recognized by the public and have not been well adopted in the food industry. Therefore, a comprehensive review of PSS, including its material basis, flavor characteristics, and taste mechanism is helpful for a deeper understanding of PSS, accelerating its research and development, and promoting its application.

Adherence to mediterranean diet and aromatic plants intake are related with gustatory function: A case-study from a Portuguese region

The Mediterranean Diet has been recognized as one of the healthiest and most sustainable dietary patterns and is flavor rich due to the use of different seasonings, such as aromatic plants, in dish confection. Based on the hypotheses that: 1) gustatory function will affect food choices; 2) seasoning flavors may be differently accepted according to individuals' gustatory functions; the aim of the present study was to assess the association between taste sensitivity and/or preference with Mediterranean Diet adherence and seasoning consumption. A total of 383 adults (18-59 years old; 198 female, 185 male) from North Alentejo region of Portugal were enrolled in this study, with 291 (145 female and 146 male) also evaluated for gustatory function. Recognition thresholds were obtained for four tastes (sweet, sour, salty, and bitter) and astringency, as well as preference level for the highest concentration of each stimulus tested. A validated Food Frequency Questionnaire was filled out, and MD adherence was extrapolated from the answers of the Food Frequency Questionnaire according to the Mediterranean Diet Adherence Screener (MEDAS) score. In total, 20.8% of the individuals presented low, 58.2% medium, and 21.0% high adherence. Adherence was higher in women than men and in older individuals than younger adults. Adherence to the Mediterranean Diet was positively correlated with aromatic plants consumption but not spices. Seasonings were associated with gustatory function, and the cluster with higher consumption presented higher preferences for bitter and salty tastes. Total sodium intake was also higher in this cluster, suggesting that these individuals prefer stronger oral sensations. In conclusion, this study shows that MD adherence is not high, even in regions with rural characteristics. The observed association of MD and seasoning intake with gustatory function do underline the usefulness of this information in strategies aimed at promoting healthy and sustainable eating patterns.

Synergistic effect of combining umami substances enhances perceived saltiness

Umami substances have the potential to enhance the perception of saltiness and thus reduce sodium intake. Two sensory evaluation experiments were conducted, involving participants tasting salt solutions, and solutions with added umami substances at equal sodium concentrations. Umami substances included sodium glutamate (MSG), disodium inosinate (IMP), and the combination of them which has a synergistic effect and is a closer match to commonly-consumed foods. In Experiment 1, using the two-alternative forced-choice (2-AFC) method by 330 consumers, paired comparisons were conducted at three different sodium concentrations. The combination of MSG and IMP enhanced the perception of saltiness (p < .001 in the difference test), whereas presenting either umami substance in isolation failed to do so (p > .05 in the similarity test). Significant order effects occurred in paired comparisons. In Experiment 2, a two-sip time-intensity (TI) analysis with trained panellists verified these results and found that tasting MSG and IMP either simultaneously or successively enhanced saltiness perception at equal sodium concentrations. These findings indicate that the synergistic effect of umami substances may be the cause of saltiness enhancement, and represents a potential strategy for sodium reduction while satisfying the consumer demand for saltiness perception. Considering the application in food processing and in food pairing, umami substances can potentially be used to help to reduce salt intake in food consumption.

Role of taste receptors in salty taste perception of minerals and amino acids and developments in salt reduction strategies: A review

Salt (sodium chloride) plays a key role in maintaining the textural, microbiological, and sensorial aspects of the foods. However high dietary salt intake in the population has led to a series of health problems. Currently manufacturers are under pressure to reduce the sodium levels in foods without compromising the consumer experience. Because of the clean salty taste produced by sodium chloride, it has been challenging for the food industry to develop a suitable salt substitute. Studies have shown that different components within a food matrix can influence the perception of saltiness. This review aims to comprehend the potential synergistic effect of compounds such as minerals and amino acids on the perception of saltiness and covers the mechanism of perception where relevant to taste resulting from sodium ions and other metallic ions (such as K, Mg, Ca), as well as various amino acids and their derivatives. Finally, the review summarizes various salt reduction strategies explored by researchers, government organizations and food industry, including the potential use of plant-based extracts.

Study on the saltiness-enhancing mechanism of chicken-derived umami peptides by sensory evaluation and molecular docking to transmembrane channel-like protein 4 (TMC4)

The previously obtained chicken-derived umami peptides in the laboratory were evaluated for their saltiness-enhancing effect by sensory evaluation and S-curve, and the results revealed that peptides TPPKID, PKESEKPN, TEDWGR, LPLQDAH, NEFGYSNR, and LPLQD had significant saltiness-enhancing effects. In the binary solution system with salt, the ratio of the experimental detection threshold (129.17 mg/L) to the theoretical detection threshold (274.43 mg/L) of NEFGYSNR was 0.47, which had a synergistic saltiness-enhancing effect with salt. The model of transmembrane channel-like protein 4 (TMC4) channel protein was constructed by homology modeling, which had a 10-fold transmembrane structure and was well evaluated. Molecular docking and frontier molecular orbitals showed that the main active sites of TMC4 were Lys 471, Met 379, Cys 475, Gln 377, and Pro 380, and the main active sites of NEFGYSNR were Tyr, Ser and Asn. This study may provide a theoretical reference for low-sodium diets.

Analysis of ingredient list and nutrient composition of plant-based burgers available in the global market

The nutrient composition of plant-based burgers is a key factor when making their purchase/consumption decision to maintain a balanced diet. For this reason, ingredient list and nutritional information of burgers launched in the global market were retrieved from their labels. Products were classified based on the technology development, market position and region of the manufacturer. From the ingredient analysis, we observed a high heterogeneity in the ingredients used, a predominance of soy and wheat as main sources of proteins, and the increasing use of new protein sources (e.g. peas, other types of beans and pseudo-cereals). Oil was the most cited ingredient followed by salt. Nutritional composition varied mainly depending on the region with no clear pattern among countries. To less extent, technology development resulted in traditional products with lower amounts of protein and higher amounts of carbohydrates. Vegan and vegetarian products showed limited differences due to the high intra-heterogenicity.

Novel NaCl reduction technologies for dry-cured meat products and their mechanisms: A comprehensive review

Sodium chloride (NaCl) confers a unique flavor and quality in meat products, however, due to growing concerns about the adverse effects of excessive NaCl consumption, how to reduce NaCl content while ensuring quality and safety has become a research hotspot in this field. This review mainly discusses the role of NaCl in dry-cured meat, as well as novel salt-reducing substances that can substitute for the effects of NaCl to achieve sodium reduction objectives. New technologies, such as vacuum curing, ultrahigh pressure curing, ultrasonic curing, pulsed electric field curing, and gamma irradiation, to facilitate the development of low-sodium products are also introduced. The majority of current salt reduction technologies function to enhance salt diffusion and decrease curing time, resulting in a decrease in NaCl content. Notably, future studies should focus on implementing multiple strategies to compensate for the deficiencies in flavor and safety caused by NaCl reduction.

Saltiness enhancement by "má là" umami flavor in NaCl model aqueous and oil-added systems

The health concerns associated with high dietary sodium and the quest for a sensory experience have prompted the need for new strategies that can reduce the salt content of foods and have good acceptability. To investigate the cross-modal interaction effects of "má là" umami flavor (total of eight carriers) on the saltiness perception and effective sodium reduction in low-to-strong NaCl aqueous solutions (0.203 %-1.39 %) and oil-added systems (5 %, 10 %, 15 %, 20 %, 25 % canola oil, wt%), sixteen assessors were selected and two methods including saltiness intensity comparison with a category scale and rating with a generalized Labeled Magnitude Scale (gLMS) were used. The results showed PnSnUn carriers significantly enhance saltiness at moderate-to-strong NaCl solutions, and higher saltiness intensity with the addition of canola oil, especially at 25 % oil level. In addition, based on the developed Stevens' power function the sodium reduction was calculated, it was evident that two "má là" umami flavor combinations (one flavor combination was low "má", low "là" and moderate umami, and the other flavor combination with moderate "má", low "là" and moderate umami) were found to perform best with maximum sodium reduction of 18.88 % and 18 %, respectively, and when incorporating 25 % canola oil, the maximum sodium reduction raised by approximately 10 % (to 28.00 % and 28.42 %). This research not only confirmed the positive modulating effect of the "má là" umami flavor on saltiness perception in NaCl solutions, but also showed that the presence of oil further enhanced this effect. This work offered a new and promising insight into the development of foods with reduced sodium content while maintaining the saltiness properties.

Maillard reaction products of pea protein hydrolysate as a flavour enhancer for beef flavors: Effects on flavor and physicochemical properties

This study evaluated the effects of Maillard reaction products of pea protein hydrolyzates (MRPs-PPH) as salt-reducing and umami-enhancing components on the flavor and physicochemical properties of beef flavors. The addition of MRPs-PPH reduced the brightness of beef flavors, increased the redness and yellowness, as well as changed the texture characteristics of beef flavors. With the addition of MRPs-PPH, the apparent viscosity, storage modulus and loss modulus of beef flavors decreased. Finally, the relationship between taste attributes and flavor compounds of the samples was analyzed by Partial Least Squares Regression (PLSR), and flavor compounds with significant positive contributions to different taste attributes were found. This study showed that MRPs-PPH could be used as a flavor enhancer derived from biomacromolecules with salt reduction and freshness enhancement.

Sensory, structural breakdown, microstructure, salt release properties, and shelf life of salt-coated air-dried yellow alkaline noodles

Salt reduction in food has been employed to improve public health. The effects of salt coatings on sodium content, sensory properties, structural breakdown, microstructure, salt release properties, and shelf life of yellow alkaline noodles (YAN) were evaluated. 15 g/dL resistant starch HYLON™ VII (HC) or 5% (v/v) Semperfresh™ (SC) with 10, 20, and 30 g/dL sodium chloride (NaCl) were used. HC-Na30 and SC-Na30 had the highest sodium content and came closest to commercial YAN in taste and saltiness perception. Structural improvement was demonstrated with HC-Na10 and SC-Na10 as both noodles required maximum work to be broken down. Moreover, SEM micrographs of these noodles showed a more compact and dense appearance with increased continuity of the matrix and fewer voids and hollows. However, ruptured surfaces were observed in noodles coated with 20 and 30% salt. The enhanced salt release from the coatings was demonstrated in an in vivo analysis, with the released salt occurring rapidly from HC and SC coatings. HC-Na10 and SC-Na10 noodles had a shelf life of more than 8 days when stored at 4 °C, which is longer than HC-Na0 and SC-Na0 noodles. Storage at 4 °C decelerated the microbiological growth, changes in pH and CIE L* values in salt-coated noodles than storage at 25 °. Thus, HC-Na10 and SC-Na10 could be suitable formulations to replace commercial YAN.

Impurities of natural salts of the earth

In this study, 18 different samples of unrefined coarse food salt were examined using inductively coupled plasma mass spectrometry and Fourier transform infrared spectroscopy. Additionally, microphotographs were taken to determine the visual distribution of the impurities in the salt samples. None of the salt samples analysed contained arsenic, mercury, tin, and antimony. Cadmium, chromium, nickel, lead, barium, lithium, aluminium, titanium, vanadium, cobalt, cupper, iron, zinc, manganese, magnesium, and calcium were determined in some salt samples. According to the results of FTIR analysis mainly polyamide polymer derivatives were found in Himalaya White, Himalaya, Klodawa, Nakhchivan, Delice, Guérande Flake, Guérande Celtic, Maldon, Havaii Black, Havaii Green, Havaii Red, Maras, and İzmir salts.

Sodium reduction in foods: Challenges and strategies for technical solutions

In many parts of the world, sodium consumption is higher than recommended levels, representing one of the most important food-related health challenges and leading to considerable economical costs for society. Therefore, there is a need to find technical solutions for sodium reduction that can be implemented by food producers and within food services. The aims of this review are to discuss the barriers related to sodium reduction and to highlight a variety of technical solutions. The barriers relate to consumer perception, microbiology, processing, and physicochemistry. Existing technical solutions include inhomogeneous salt distribution, coated salt particles, changing particle sizes and forms, surface coating, multisensory combinations, sodium replacements, double emulsions, adapted serum release by microstructure design, and adapted brittleness by microstructure design. These solutions, their implementation and the associated challenges, and applicable product categories are described. Some of these solutions are ready for use or are in their early development stages. Many solutions are promising, but in most cases, some form of adaptation or optimization is needed before application in specific products, and care must always be taken to ensure food safety. For instance, further research and innovation are required in the dynamic evolution of saltiness perception, consumer acceptance, the binding and migration of sodium, juiciness, microbiological safety, and the timing of salt addition during processing. Once implemented, these solutions will undoubtedly support food producers and food services in reducing sodium content and extend the application of the solutions to different foods.

Evaluation of Chemical and Sensory Characteristics of Sauerkraut Juice Powder and its Application in Food

Sauerkraut juice is rich in bioactive compounds; however, it is considered a byproduct of the production process. An innovative solution was found through the process of spray-drying to obtain sauerkraut juice powder. The aim of this study was to evaluate chemical and sensory characteristics of sauerkraut juice powder (SJP) and its application in foodstuffs. For SJP, total phenol content, antiradical activity, and nutritional value were determined, and the results showed that SJP is rich in minerals, especially calcium and potassium, as well as organic acids and vitamin C. SJP contains 12% NaCl and a total phenol content of 359.54 mg GAE 100 g^-1 dw. SJP has umami attributes, such as sweet, sour, and salty. Sensory tests-descriptive, rate-all-that-apply, overall liking, and volatile profile determination-were carried out separately in SJP experimental samples with olive oil and sour cream. Among the sweet, sour, and salty flavours, garlic, yogurt, and mayonnaise were also mentioned. In the detection of volatile compounds, leafy and grassy green aromas with light almond were identified in the samples with olive oil and butter and rancid cheese and fishy/amine odours were identified in samples with sour cream. There were significant differences in the overall likability of samples, but the experimental samples with SJP were more popular than control samples; therefore, SJP may be used as a salt alternative in food applications.

Sodium Reduction in Traditional Dry-Cured Pork Belly Using Glasswort Powder (Salicornia herbacea) as a Partial NaCl Replacer

Sodium chloride (NaCl) is a key ingredient in the processing of traditional dry-cured meat products by improving microbial safety, sensory attributes and technological properties. However, increasing concern about the consumption of sodium and health has been supporting the development of low-sodium meat products. Several strategies to reduce sodium in dry-cured meat product have been tested, although the followed approaches sometimes result in undesirable characteristics concerning flavor, texture and mouthfeel. The use of halophytic plants such as glasswort (Salicornia herbacea) in food matrices has been suggested as a novel strategy to reduce sodium content, due its salty flavor. The main aim of the present study is to produce traditional dry-cured pork bellies from the Bísaro breed using glasswort as a NaCl partial replacer, and compare it with dry-cured bellies salted either with NaCl or a mix of NaCl + KCl. Control bellies (BC) were salted with 100% of NaCl, the second formulation (BK) had 50% of NaCl and 50% of KCl, and the third formulation (BG) had 90% of NaCl and 10% of glasswort powder (GP). After production, the bellies were evaluated for a_w, pH, CIELab coordinates, weight loss, proximal composition, TBARS, collagen and chloride contents, fatty acid profile and sensory attributes. The use of BG in dry-cured pork bellies did not affect processing indicators such as weight loss, a_w and pH. Concerning CIELab, only the coordinates L* and hue angle from the external surface color of BG were statistically different from BC and BK. As expected, ash and NaCl contents differed from BG to the other two formulations. SFA and indexes AI and TI were lower, whereas the MUFA and h/H ratio were higher in BG than other treatments, leading to a product with a healthier lipid profile. The sensory evaluation revealed differences in appearance, taste and flavor among treatments, but did not indicate any negative effects of BG in the product attributes. This study reinforces the potential of BG as a natural sodium reducer for the production of traditional dry-cured pork bellies.

Heterocyclic aromatic amine contents and quality characteristics of bacon as influenced by NaCl concentration of brine

Bacon usually have a high salt content. Excessive intake of salt could cause a harm to human health. Heterocyclic aromatic amines (HAAs) are carcinogenic and mutagenic heterocyclic compounds formed by the reactions of precursor substances at high temperature. This study investigated the influence of different levels of NaCl on the HAA contents and quality characteristics of bacon. Moisture, a_w , L* value, b* value, thiobarbituric acid-reactive substance (TBARS), and carbonyl content increased significantly with a decrease in the NaCl concentration of the brine (p < 0.05). There were no significant differences between treatments for a* value, pH, creatine content, sensory redness, bitterness, or off-odor (p > 0.05). Sensory evaluation showed that saltiness in bacon increased significantly with increased NaCl concentrations in brine. The increased NaCl concentrations decreased the total HAAs in fried bacon (p < 0.05). Moreover, the nonpolar HAA contents in bacon were higher than the polar HAA contents; salt concentration mainly affected the nonpolar HAA content. In summary, salt content had a significant influence on the HAA content and the quality characteristic of bacon.

Development of Strategies to Manufacture Low-Salt Meat Products – A review

Urbanization is usually followed by changes in eating habits, with a specific trend toward the consumption of ready-to-eat products, such as processed foods. Among the latter, meat products are known contributors to high dietary sodium owing to salt addition. Salt plays an essential role in maintaining the quality of meat products in terms of acceptability and safety. However, an excessive salt intake is linked to high blood pressure and cardiovascular diseases. Hence, several studies have been competing for the discovery of salt alternatives performing in a similar way as common salt. A number of replacements have been proposed to reduce salt consumption in meat products while taking into account consumer preferences. Unfortunately, these have resulted in poorer product quality, followed by new adverse effects on health. This review addresses these recent issues by illustrating some established approaches and providing insight into further challenges in developing low-salt meat products.

Effect of the Partial Substitution of Sodium Chloride on the Gel Properties and Flavor Quality of Unwashed Fish Mince Gels from Grass Carp

Excessive salt is usually required to maintain good gel properties and quality characteristics for unwashed fish mince gels (UFMG). This study aimed to investigate the effects of partial sodium chloride substitution (30%) with different substitutes (potassium chloride, disodium inosine-5′-monophosphate, basil) on the gel and flavor properties of UFMG from Ctenopharyngodon idellus. The results indicated that the texture and gel strength of NK (30% NaCl was replaced with 30% KCl) were fairly similar to that of N group (NaCl only), and the whiteness had improved significantly (p < 0.05), while the product eventually yielded a certain bitter taste. The addition of disodium inosine-5′-monophosphate (DIMP) significantly (p < 0.05) increased the hardness, chewiness, buriedness degree of tryptophan and gel strength, decreased the content of α-helix structure in the gels, while less change occurred in gel whiteness and network structure. Basil significantly (p < 0.05) reduced the buriedness degree of tryptophan, gel strength and whiteness, and deteriorated the gel structure. Nevertheless, the addition of DIMP or basil reduced the bitterness induced by KCl and improved the overall acceptability scores of gels of the N group. Moreover, there was no distinct difference in moisture content and water-holding capacity between all groups. Therefore, replacing sodium chloride in UFMG with 25% potassium chloride and 5% DIMP may be an ideal sodium salt substitution strategy.

Hypertension- and glycaemia-lowering effects of a grape-pomace-derived seasoning in high-cardiovascular risk and healthy subjects. Interplay with the gut microbiome

Purpose: Grape pomace (GP) is a winery by-product rich in polyphenols and dietary fibre. Some recent results suggest that GP-derived extracts could be promising additives in food, specially recommended for low-salt diets. The hypothesis tested in this paper is that the regular consumption of GP-derived seasonings could help in the control of hypertension and glycaemia. Methods: A randomized intervention study (6 weeks) was performed in high-risk cardiovascular subjects (n = 17) and in healthy subjects (n = 12) that were randomly allocated into intervention (2 g day^-1 of GP seasoning) or control (no seasoning consumed) groups. Blood samples, faeces, urine and blood pressure (BP) were taken at the baseline and at the end of the intervention. Faecal samples were analysed for microbiota composition (16S rRNA gene sequencing) and microbial-derived metabolites (short chain fatty acids and phenolic metabolites). Results: Among the clinical parameters studied, BP and fasting blood glucose significantly decreased (p < 0.05) after the seasoning intervention, but not for the control group. Notably, application of a novel approach based on ASV (Amplicon Sequence Variant) co-occurrence networks allowed us to identify some bacterial communities whose relative abundances were related with metadata. Conclusion: Our primary findings suggest that GP-seasoning may help in the modulation of cardiometabolic risk factors, mainly in the early stages. Furthermore, it evidences modulation of gut microbiota and functional bacterial communities by grape pomace, which might mediate the cardiometabolic effects of this by-product.

The structure and flavor of low sodium seasoning salts in combination with different sesame seed meal protein hydrolysate derived Maillard reaction products

•

The structural and physicochemical properties of a low sodium MRPs were investigated..

•

Different MRPs low sodium seasoning salts had better flavor characteristics.

•

CMS had the largest bulk density and the highest sensory score.

•

SMS had good hygroscopicity and thermal stability during storage.

•

TMS had the highest solubility, which is significant for its use as seasoning salt.

In recent years, Maillard peptides have attracted considerable attention of food researchers due to their distinct flavor properties in food processing. We investigated the structure and flavor properties of the newly developed low-sodium seasoning salt with sesame seed hydrolysate Maillard products (SSH-MRPs), cysteine Maillard products (Cys-MRPs), methionine Maillard products (Met-MRPs), and thiamine Maillard products (Thi-MRPs). Compared to the control group, the Cys-MRPs salt (CMS) had the smallest angle of repose, the highest bulk density, and the highest sensory score. The seasoning salt with SSH-MRPs (SMS) had appreciable hygroscopicity and thermal stability. The seasoning salt with Thi-MRPs (TMS) had the highest solubility. These MRPs seasoning salts showed better flavor characteristics and physicochemical properties, suggesting that MRPs can replace part of NaCl to develop new low sodium seasoning salts and promote their application in food flavoring systems.

Spices and Seasoning Mixes in European Union-Innovations and Ensuring Safety

Spices are an important group of food products of great importance in nutrition and food technology. They are mainly used to shape the sensory properties of food in gastronomy, in home cooking, and in industry. Ensuring quality and safety is one of the basic tasks of spice producers. The aim of this review is to present the threats to the consumer related to the presence of spices and seasoning mixes in the diet. Therefore, special attention was paid to such risks as excess sodium chloride (and sodium) in spice mixtures, the use of additives influencing the sensory experience, and irregularities in the labeling of spices and seasoning mixes for the presence of additives and allergens. The threats regarding microbiological safety and the presence of heavy metals, pesticides, plant protection products, as well as synthetic fertilizers and undeclared additives are also presented and the issue of adulteration and lack of authenticity of spices and spice mixtures is discussed. Using data from IJHARS planned inspections and notifications registered in the EU Rapid Alert System for Food and Feed (RASFF) for 2015-2019, as well as the results of own research, an analysis of the risks caused by herbs and spices was carried out. Strategic activities of companies producing spices focus, among others, on improving production and expanding the commercial offer with new, attractive products. The article reviews product and process innovations in spice mixes and the methods of ensuring safety in this group of food products.

Effect of Salt Content Reduction on Food Processing Technology

Higher salt intake is associated with the risk of cardiovascular and kidney diseases, hypertension and gastric cancer. Salt intake reduction represents an effective way to improve people’s health, either by the right choice of food or by a reduction of added salt. Salt substitutes are often used and also herb homogenates are treated by high pressure technology. Salt reduction significantly influences the shelf life, texture, pH, taste, and aroma of cheese. The composition of emulsifying salts or starter cultures must be modified to enact changes in microbial diversity, protease activity and the ripening process. The texture becomes softer and aroma atypical. In bakery products, a salt reduction of only 20–30% is acceptable. Water absorption, dough development, length and intensity of kneading and stability of dough are changed. Gluten development and its viscoelastic properties are affected. The salt reduction promotes yeast growth and CO₂ production. Specific volume and crust colour intensity decreased, and the crumb porosity changed. In meat products, salt provides flavour, texture, and shelf life, and water activity increases. In this case, myofibrillar proteins’ solubility, water binding activity and colour intensity changes were found. The composition of curing nitrite salt mixtures and starter cultures must be modified.

Gastrointestinal Digestion of a Grape Pomace Extract: Impact on Intestinal Barrier Permeability and Interaction with Gut Microbiome

Grape pomace (GP) is a winemaking by-product rich in polyphenols and fibre. Supplementation with GP extracts has shown potential benefits against oxidative stress- and inflammation-related pathologies. As a new nutritional target, this paper explores the impact of the ingestion of a grape pomace extract on intestinal barrier functionality. A GP extract was sequentially subjected to gastrointestinal and colonic digestion using the dynamic gastrointestinal simulator (simgi^®). This generated two simulated fluids: intestinal-digested extract (IDE) and colonic-digested extract (CDE). The effects of these two fluids on paracellular permeability and the expression of tight junction (TJ) proteins (i.e., zonula occludens-1 (ZO-1) and occludin) were assessed in Caco-2-cell monolayers grown in Transwell^® inserts. The IDE fluid significantly (p < 0.001) reduced the paracellular transport of FITC-dextran with respect to the control, whereas no significant differences (p > 0.05) were found for CDE, which could be due, at least partially, to the pro-leaky effect of the colonic digestion medium. Accordant slight increases in the mRNA levels of both ZO-1 and occludin were observed for IDE, but without statistical significance. Additionally, the colonic fermentation of the GP extract promoted the production of short-chain fatty acids (SCFA) and phenolic metabolites and led to changes in the relative abundance of some bacteria that might affect paracellular permeability. Overall, this paper reports first trends about the effects of grape pomace extracts on intestinal permeability that would require further confirmation in future experiments.