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In this study, we present a computational framework designed to evaluate virtual scenarios of cardiac resynchronization therapy (CRT) and compare their effectiveness based on relevant clinical biomarkers. Our approach involves electro-mechanical numerical simulations personalized, for patients with left bundle branch block, by means of a calibration obtained using data from Electro-Anatomical Mapping System (EAMS) measures acquired by cardiologists during the CRT procedure, as well as ventricular pressures and volumes, both obtained pre-implantation. We validate the calibration by using EAMS data coming from right pacing conditions. Three patients with fibrosis and three without are considered to explore various conditions. Our virtual scenarios consist of personalized numerical experiments, incorporating different positions of the left electrode along reconstructed epicardial veins; different locations of the right electrode; different ventriculo-ventricular delays. The aim is to offer a comprehensive tool capable of optimizing CRT efficiency for individual patients. We provide preliminary answers on optimal electrode placement and delay, by computing some relevant biomarkers such as d P / d t max , ejection fraction, stroke work. From our numerical experiments, we found that the latest activated segment during sinus rhythm is an effective choice for the non-fibrotic cases for the location of the left electrode. Also, our results showed that the activation of the right electrode before the left one seems to improve the CRT performance for the non-fibrotic cases. Last, we found that the CRT performance seems to improve by positioning the right electrode halfway between the base and the apex. This work is on the line of computational works for the study of CRT and introduces new features in the field, such as the presence of the epicardial veins and the movement of the right electrode. All these studies from the different research groups can in future synergistically flow together in the development of a tool which clinicians could use during the procedure to have quantitative information about the patient's propagation in different scenarios., Competing Interests: Declarations Conflict of interest The authors declare to have no conflict of interest. Ethical approval and consent to participate Ethical review board approval and informed consent were obtained from all patients., (© 2024. The Author(s).)

Purpose: A strategy to reduce starch digestibility is to limit its accessibility to α-amylase by preserving the integrity of cells where starch is encapsulated. Coarse flour is rich in intact cells and can be used for this purpose. However, making bread with coarse flour negatively affects crumb cohesiveness, which may increase the gastric disintegration rate, and enhance starch accessibility. Therefore, this study aimed to assess the combined effect of coarse semolina and its 20% gluten substitution in bread in healthy volunteers on glycemic and insulinemic responses, oral processing and bolus characteristics., Methods: Apparently, healthy volunteers (n = 16) randomly consumed bread made with coarse semolina and 20% gluten substitution (80CS_20G), its counterpart with fine semolina (80FS_20G), and bread with fine semolina and 5% gluten (95FS_5G). The glycemic and insulinemic responses were measured over 2 h after bread consumption. Mastication behaviour, bolus properties and reducing sugar were also evaluated., Results: No differences in glycemic responses and mastication were observed among the samples. 80CS_20G and 80FS_20G exhibited similar textural properties but 80CS_20G released less reducing sugars and elicited a lower insulin response at 30 min than 80FS_20G, probably due to intact cells that limit starch accessibility. Also, 95FS_5G released lower reducing sugars and had lower insulin peak than 80FS_20G. The compact structure of 95FS_5G may have delayed starch hydrolysis by restricting α-amylase accessibility., Conclusion: Combining gluten and coarse semolina resulted in bread with a lower release of reducing sugars, a reduced insulinemic peak and textural properties similar to the counterpart with fine semolina., Clinical Trial Registration Number: The trial is registered at ClinicalTrials.gov: NCT06152874., Competing Interests: Declarations Ethical approval The study was approved by the Institutional Review Board of the Department of Agricultural, Food, Environmental and Animal Sciences of the University of Udine (protocol number: 0003800 on July 18th 2023). Informed consent to participate All participants signed the informed consent according to the Helsinki Declaration on human rights. Conflict of interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Enrichment of staple foods with proteins can be a solution to tackle protein-energy malnutrition in the elderly. For instance, bread can be enriched with pea proteins that are cheap, sustainable and easily digestible. Non-conventional technologies, such as high pressure homogenization (HPH), can improve the digestibility of plant proteins. To characterize the health functionality of pea-enriched bread, a functional bread tailored to elderly consumers was developed by substituting 5% wheat flour with untreated or HPH-treated pea protein concentrate. Protein digestibility and colon fermentability were assessed by mimicking elderly in vitro gastrointestinal and gut microbiota conditions and compared with adult conditions. Bread reformulation with pea proteins affected physical and chemical properties and produced an increase in hardness, which is one of the key features for the acceptability of bread by the elderly. The highest hardness value was observed for pea protein bread, followed by HPH-treated pea protein bread and wheat bread. In vitro protein digestibility and fermentability were affected by reformulation and by physiological digestive conditions, with lower digestibility under elderly conditions compared to adult ones. The obtained results may contribute to a better understanding of food digestibility under different gastrointestinal conditions and its dependence on physiological and formulation factors, and ultimately would help to design age-tailored foods.

In cereal products, the use of flour containing clusters of intact cells has been indicated as a potential strategy to decrease starch digestion. Rye possesses more uniform and thicker cell walls than wheat but its protective effect against starch digestion has not been elucidated. In this study, rye flours with three different particle sizes, large (LF) (∼1700 μm), medium (MF) (∼1200 μm), and small (SF) (∼350 μm), were used to produce model bread. The textural properties of these breads were analysed using Textural Profile Analysis (TPA). The starch digestibility of both the flour and the bread was measured using Englyst's method, while the presence of intact cell clusters was examined using Confocal Laser Scanning Microscopy (CLSM). Additionally, the disintegration of bread digesta during simulated digestion was assessed through image analysis. CLSM micrographs revealed that bread made with MF and LF retained clusters of intact cells after processing, whereas bread made with SF showed damaged cell walls. Starch digestibility in LF and MF was lower (p ≤ 0.05) than that in SF. Bread produced with MF and LF exhibited the least (p ≤ 0.05) cohesive and resilient texture, disintegrated more during digestion, and exhibited higher starch digestibility (p ≤ 0.05) than bread made with SF. These results highlight the central role of bread texture on in vitro starch digestibility., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background: Children with Down syndrome (DS) experience more difficulties with oral motor skills, including chewing, drinking, and swallowing. The present study attempts to measure the preliminary effectiveness of Global Intensive Feeding Therapy (GIFT) in DS. GIFT is a new rehabilitation program addressing the specific difficulties and needs of each child, focusing on sensory and motor oral abilities. It follows an intensive schedule comprising 15 sessions over 5 consecutive days, with 3 sessions per day. The principles of GIFT are applied with specific objectives for DS., Methods: GIFT was preliminarily implemented among 20 children diagnosed with DS. To measure the efficacy of GIFT, the Karaduman Chewing Performance Scale (KCPS), the International Dysphagia Diet Standardization Initiative (IDDSI), and the Pediatric Screening-Priority Evaluation Dysphagia (PS-PED) were used. Data were analyzed using the Wilcoxon signed-rank test before (T0) and after intervention (T1) and at one-month follow-up (T2). The effect size was also measured for specific outcomes, using Kendall's W., Results: Our findings revealed that children with DS showed no risk of dysphagia according to the PS-PED (mean score 2.80). Furthermore, statistically significant improvements in chewing performance were observed, as measured by the KCPS ( p < 0.01), as well as in texture acceptance and modification, as measured by the IDDSI post-intervention ( p < 0.01). For both the KCPS and IDDSI, a large effect size was found (Kendall's W value > 0.8). Parents/caregivers continued using GIFT at home, and this allowed for a positive outcome at the one-month follow-up., Conclusions: GIFT proved to be effective in the rehabilitation of feeding and swallowing disorders in children with DS, as well as for food acceptance.

In recent years, the role of microbial tryptophan (Trp) catabolism in host-microbiota crosstalk has become a major area of scientific interest. Microbiota-derived Trp catabolites positively contribute to intestinal and systemic homeostasis by acting as ligands of aryl hydrocarbon receptor and pregnane X receptor, and as signaling molecules in microbial communities. Accumulating evidence suggests that microbial Trp catabolism could be therapeutic targets in treating human diseases. A number of bacteria and metabolic pathways have been identified to be responsible for the conversion of Trp in the intestine. Interestingly, many Trp-degrading bacteria can benefit from the supplementation of specific dietary fibers and polyphenols, which in turn increase the microbial production of beneficial Trp catabolites. Thus, this review aims to highlight the emerging role of diets and food components, i.e., food matrix, fiber, and polyphenol, in modulating the microbial catabolism of Trp and discuss the opportunities for potential therapeutic interventions via specifically designed diets targeting the Trp-microbiome axis.

The current consumption trends, combined with the expected demographic growth in the coming years, call for a protein transition, i.e., the partial substitution of animal protein-rich foods with foods rich in proteins produced in a more sustainable way. Here, we have discussed some of the most common and promising protein sources alternative to animal proteins, namely: legumes, insects, and microorganisms (including microalgae and fungi). The primary objective was to assess their nutritional quality through the collection of digestible indispensable amino acid score (DIAAS) values available in the scientific literature. Protein digestibility corrected amino acid score (PDCAAS) values have been used where DIAAS values were not available. The ecological impact of each protein source, its nutritional quality and the potential applications in traditional foods or novel food concepts like meat analogues are also discussed. The data collected show that DIAAS values for animal proteins are higher than all the other protein sources. Soybean proteins, mycoproteins and proteins of some insects present relatively high DIAAS (or PDCAAS) values and must be considered proteins of good quality. This review also highlights the lack of DIAAS values for many potentially promising protein sources and the variability induced by the way the proteins are processed.

This study explored differences in microbial lipid metabolites among sunflower seeds, soybeans, and walnuts. The matrices were subjected to in vitro digestion and colonic fermentation. Defatted digested materials and fiber/phenolics extracted therefrom were added to sunflower oil (SO) and also fermented. Targeted and untargeted lipidomics were employed to monitor and tentatively identify linoleic acid (LA) metabolites. Walnut fermentation produced the highest free fatty acids (FFAs), LA, and conjugated LAs (CLAs). Defatted digested walnuts added to SO boosted FFAs and CLAs production; the addition of fibre boosted CLAs, whereas the addition of phenolics only increased 9e,11z-CLA and 10e,12z-CLA. Several di-/tri-hydroxy-C18-FAs, reported as microbial LA metabolites for the first time, were annotated. Permutational multivariate analysis of variance indicated significant impacts of food matrix presence and type on lipidomics and C18-FAs. Our findings highlight how the food matrices affect CLA production from dietary lipids, emphasizing the role of food context in microbial lipid metabolism., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The effect of two processing methods of Jack beans ( i.e. cooked bean (CB) and cooked tempeh (CT)) on the in vitro digestibility of protein and starch, as well as the production of short chain fatty acids (SCFAs), γ-aminobutyric acid (GABA), and tryptophan (Trp) metabolites after in vitro colonic fermentation, was investigated. CT was obtained by fungal fermentation after cooking under acidic conditions. CT had significantly higher protein, lower digestible starch, lower total fiber, higher free phenolic compounds, and higher ash content compared to CB. CT exhibited better in vitro protein digestibility than CB and less glucose release during in vitro digestion than CB. A comparable concentration of total SCFAs and GABA was produced after in vitro fermentation of CB and CT, but CB produced more indole than CT, resulting in higher amounts of total Trp metabolites. In summary, our findings show that tempeh fermentation improves the nutritional quality of Jack beans and describe the impact of fermentation on the digestibility of nutrients and the formation of metabolites during colonic fermentation.

The aim of this study was to investigate the effects of carrot shape (cube vs. julienne) and oral processing behaviour, specifically chewing time, on bolus properties and bioaccessibility of β-carotene in raw carrots. Participants (n = 20) consumed raw carrot cubes (15 × 15 × 15 mm, 4.2 g/bite) and raw carrot julienne (2 × 3 × 90 mm, 4.2 g/bite) with normal (cube: 20 s/bite; julienne: 28 s/bite) and short (cube: 10 s/bite; julienne: 14 s/bite) chewing time. Expectorated boli were collected and characterized for number and mean area of carrot bolus particles. The proportion of easily extractable β-carotene of the carrot bolus was taken as an approximate indicator of the potentially bioaccessible β-carotene. Longer chewing time resulted in significantly more and smaller carrot bolus particles, larger particle surface area (p < 0.01) and higher proportion of easily extractable β-carotene than shorter chewing of raw carrots of both shapes (Cube&#95;Normal vs. Cube&#95;Short: 29 ± 7 % vs. 23 ± 7 %; Julienne&#95;Normal vs. Julienne Short: 31 ± 8 % vs. 26 ± 6 %, p < 0.05). Carrot shape significantly influenced number and size of bolus particles (p < 0.01) with carrot julienne generating more and smaller carrot bolus particles than carrot cubes. These differences in bolus properties between carrot julienne and cubes did not influence the proportion of easily extractable β-carotene (p > 0.05). We conclude that differences in oral processing behaviour and the corresponding differences in bolus properties produce only modest differences in β-carotene bioaccessibility of raw carrots regardless of carrot shape., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Lipids in almonds are naturally encapsulated by cell walls which may reduce the actual metabolizable energy content of almonds. Oral processing increases the accessibility of lipids to digestive enzymes by grinding the almond matrix. This study aimed to investigate the effect of adding accompanying foods (chocolate and iceberg lettuce) to almonds on oral processing behaviour, bolus properties and predicted lipid release. Natural chewing times of four almond model foods including one almond (1.3 g), four almonds (4.6 g), one almond with chocolate (4.3 g) and one almond with iceberg lettuce (4.3 g) were collected from n = 59 participants in duplicate. Expectorated boli at the moment of swallowing were characterized for number and mean area of almond bolus particles. Predicted lipid bioaccessibility was estimated using a previously validated model. At similar bite size (4.3-4.6 g), the addition of chocolate and iceberg lettuce to almonds significantly decreased ( p < 0.05) chewing time and significantly increased ( p < 0.05) eating rate compared to consumption of almonds alone. Almond bolus particle sizes were similar for almonds consumed alone (one and four almonds) and with chocolate, while consuming almonds with lettuce generated significantly fewer and larger almond bolus particles ( p < 0.05). Predicted lipid bioaccessibility of almonds consumed with iceberg lettuce was significantly lower ( p < 0.05) than for almonds consumed alone (one and four almonds) and almonds consumed with chocolate. Eating rate correlated significantly and positively with the mean area of bolus particles and significantly and negatively with predicted lipid release. In conclusion, combining almonds with other foods such as chocolate and lettuce influences oral processing behaviour and bolus properties and consequently predicted lipid bioaccessibility of almonds, highlighting the impact of food matrix and consumption context on these aspects.

Effects of whole foods on the microbial production of tryptophan-derived aryl hydrocarbon receptor (AhR) ligands in the intestine were investigated in a pig model. Ileal digesta and faeces of pigs after feeding of eighteen different foods were analyzed. Indole, indole-3-propionic acid, indole-3-acetic acid, indole-3-lactic acid, kynurenine, tryptamine, and indole-3-aldehyde were identified in ileal digesta, which were also identified in faeces but at higher concentrations except indole-3-lactic acid, together with skatole, oxindole, serotonin, and indoleacrylic acid. The panel of tryptophan catabolites in ileal digesta and faeces varied across different foods. Eggs induced the highest overall concentration of catabolites in ileal digesta dominated by indole. Amaranth induced the highest overall concentration of catabolites in faeces dominated by skatole. Using a reporter cell line, we observed many faecal samples but not ileal samples retained AhR activity. Collectively, these findings contribute to food selection targeting AhR ligands production from dietary tryptophan in the intestine., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Because of its high protein content, Jack bean (Canavalia ensiformis) is a promising alternative protein source. However, the utilization of Jack bean is limited due to the long cooking time to achieve palatable softness. We hypothesize that the cooking time may influence protein and starch digestibility. In this study, we characterized seven Jack bean collections with different optimal cooking times in terms of their proximate composition, microstructure and protein and starch digestibility. Kidney bean was included as a reference for microstructure and protein and starch digestibility. Proximate composition showed that Jack bean collections have a protein content ranging from 28.8 to 39.3%, a starch content ranging from 31 to 41%, a fiber content from 15.4 to 24.6%, and a concanavalin A content in the range 35-51 mg/g dry cotyledon. Particle sizes ranging between 125 and 250 µm were chosen as a representative sample of the whole bean to characterize microstructure and digestibility of the seven collections. Confocal laser microscopy (CLSM) revealed that Jack bean cells have an oval shape and contain starch granules embedded in a protein matrix similar to kidney bean cells. The diameter of Jack bean cells was measured by image analysis of CLSM micrographs and ranged from 103 to 123 µm, while the diameter of starch granules was 31-38 µm, comparatively larger than that of the kidney bean starch granules. Isolated intact cells were used to determine the starch and protein digestibility in the Jack beans collections. The digestion kinetics of starch followed a logistic model, whereas the digestion kinetics of protein followed a fractional conversion model. We found no correlation between optimal cooking time and kinetic parameters of protein and starch digestibility, implying that optimal cooking time is not predictive of protein and starch digestibility. In addition, we tested the effect of reduced cooking times on protein and starch digestibility on one Jack bean collection. The result showed that reducing cooking time significantly reduces starch digestibility, but not protein digestibility. The present study contributes to our understanding of the effect of food processing on protein and starch digestibility in legumes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

This study investigated the effect of high-fiber-low-protein (HF) and high-protein-low-fiber (HP) diets on microbial catabolism of tryptophan in the proximal colon (PC) and distal colon(DC) compartments of the Simulator of the Human Intestinal Microbial Ecosystem. The microbiota in PC and DC was dominated by Bacteroidetes and Firmicutes, in which Bacteroidetes were more abundant in DC (∼60% versus 50%) and Firmicutes were more abundant in PC (∼40% versus 25%). Most of the tryptophan catabolites were determined at a higher concentration in PC samples than in DC samples, but the overall concentration of tryptophan catabolites was over 10-fold higher in DC samples than that in PC samples. Interestingly, indole-3-propionic acid and oxindole were only identified in DC samples. A two-week dietary intervention by the HF diet enriched the abundance of Firmicutes in PC, whereas the HP diet enriched the abundance of Proteobacteria. Compared to the HP diet, the HF diet favored the microbial production of indole-3-acetic acid, indole-3-lactic acid, indole-3-aldehyde, and indole-3-propionic acid in both PC and DC compartments. To conclude, these findings increase the understanding of the effect of diets on the microbial production of tryptophan catabolites in the colon.

Feeding and swallowing disorders (FSD) are common during childhood, with a prevalence of 85% in children with neurodevelopmental disorders. A comprehensive screening is essential to identify FSD and improve health outcomes in a clinical setting. This study aims to develop a new Pediatric Screening tool capable of identifying FSD. This screening tool was developed in three steps: selecting variables based on clinical experience, searching the literature and finding agreement between experts with a two-round Delphi study. This process, which reached 97% of agreement between experts, led to the development of the Pediatric Screening-Priority Evaluation Dysphagia (PS-PED). PS-PED comprises 14 items divided into three main domains: clinical history, health status and feeding condition. We also carried out a pilot test for measuring internal consistency, as measured with Cronbach Coefficient alpha. Concurrent validity, as measured with Pearson correlation coefficient, was tested using a videofluoroscopy swallow study (VFSS) classified with the Penetration Aspiration Scale (PAS). The pilot test was conducted on 59 children with different health conditions. Our findings showed good internal consistency (alpha = 0.731), and a strong linear correlation with PAS (Pearson 0.824). Furthermore, comparing PS-PED and PAS scores, we find preliminary strong discriminant validity to identify children with FSD ( p < 0.01). Our results provide evidence on using the 14-item PS-PED as a screening tool for FSD in a clinical sample of children with heterogeneous disease.

Effects of pectin, inulin, and their combination on the production of microbiota-derived indoles and short-chain fatty acids (SCFAs) from different colon segments were investigated in a batch system inoculated with microbiota from proximal colon (PC) and distal colon (DC) compartments of the Simulator of Human Intestinal Microbial Ecosystem. Bacteria from DC compartment had a higher abundance of Firmicutes and a stronger capacity to produce indoles and SCFAs than bacteria from PC compartment. Fiber supplementation significantly increased the production of SCFAs, indole-3-propionic acid, and indole-3-lactic acid, but decreased the production of oxindole, tryptamine, and serotonin. Pectin specifically promoted the production of indole-3-acetic acid and indole-3-aldehyde. Interestingly, supplementation of pectin or inulin increased the relative abundance of Bacteroidetes whereas supplementation of a mixture of two fibers decreased it. Overall, these results suggest that fiber supplementation and colon segment affect the composition of gut microbiota and the microbial catabolism of tryptophan., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Reduction of starch digestibility in starchy foods is beneficial for lowering the risks for major non-communicable diseases. Preserving cell integrity is known to delay starch digestibility in flour but its effect in bread is not clear. In this study, the effect of increasing particle size on in vitro starch digestibility of durum wheat flour, dough, and bread was investigated. Cell integrity was retained during bread processing for medium (1000 µm-1800 µm), and large (>1800 µm) flour, whereas in small one cell walls were mostly damaged (<350 µm). In vitro starch digestibility of flour decreased increasing particle size, but no difference was found in dough. In bread, instead, a modest decrease of starch digestibility for the bread made by large particle was observed, likely due to its dense structure. In conclusion, a high particle size could limit starch digestibility in durum wheat flour but not in bread., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Purpose: Oral processing behaviour may contribute to individual differences in glycaemic response to foods, especially in plant tissue where chewing behaviour can modulate release of starch from the cellular matrix. The aim of this study was to assess the impact of chewing time of two starch based foods (brown rice and chickpeas) on bolus properties, in vitro starch digestion and postprandial glycaemic excursion in healthy subjects., Methods: In a cross-over trial participants (n = 26) consumed two carbohydrates-identical test meals (brown rice: 233 g; chickpeas: 323 g) with either long (brown rice: 41 s/bite; chickpeas: 37 s/bite) or short (brown rice: 23 s/bite; chickpeas: 20 s/bite) chewing time in duplicate while glycaemic responses were monitored using a continuous glucose monitoring device. Expectorated boli were collected, then bolus properties (number, mean area, saliva amylase activity) and in vitro starch digestion were determined., Results: Longer chewing resulted in significantly (p < 0.05) more and smaller bolus particles, higher bolus saliva uptake and higher in vitro degree of intestinal starch hydrolysis (DH&#95;S chewing time %) than shorter chewing for both foods (brown rice: DH&#95;S% 23 s  = 84 ± 4% and DH&#95;%S 41s  = 90 ± 6%; chickpeas: DH&#95;S% 20 s  = 27 ± 3% and DH&#95;%S 37s  = 34 ± 5%, p < 0.001). No significant effect of chewing time on glycaemic response (iAUC) (p > 0.05) was found for both meals. Brown rice showed significantly and considerably higher in vitro degree of intestinal starch hydrolysis and glycaemic response (iAUC) than chickpeas regardless of chewing time. No significant correlations were observed between bolus properties and in vitro starch hydrolysis or glycaemic response (p > 0.05)., Conclusion: Differences in the innate structure of starch based foods (brown rice compared to chickpeas) have a larger effect on postprandial glucose response than differences in mastication behaviour although oral processing behaviour showed consistent effects on bolus properties and in vitro starch digestion. Trial registration ClinicalTrials.gov identifier: NCT04648397 (First posted: December 1, 2020)., (© 2022. The Author(s).)

This research assessed the influence of fermentation and germination as well as of particle size on lignan bioaccessibility from flaxseed by simulated in vitro gastrointestinal digestion. In vitro simulated colonic fermentation was used to study lignan release and its conversion into enterolignans. In addition, tea was included as a representative sample to investigate the stability of lignans in the gastrointestinal tract. Only secoisolariciresinol (SECO) was detected in flaxseed samples. SECO bioaccessibility in fermented flaxseed was highest among all matrices but limited to ≈1% ( P < 0.001). Lignan bioaccessibility was significantly influenced by particle size too ( P < 0.001 for both). In the colon, fermented flaxseed produced the highest SECO release among all flaxseed samples (≈65%), and the highest conversion of enterolignan (≈1.0%), whereas the conversion of lignans in tea brew was relatively high (≈15%). Lignan conversion varies greatly among donors due to inter-individual differences in microbiota activity. Food fermentation could be a viable strategy for increasing lignan release and conversion to enterolignan.

In this study, the nature of lentil protein-tannic acid (LPTA) interaction and its effect on in vitro pepsin digestion were investigated. LPTA mixtures containing 1% w/v LP and 0.001-0.5% TA were prepared and characterized in terms of particle size, thermal properties, and secondary and tertiary structures. A 20-fold increase in particle size was observed in LPTA0.5% compared to LP control (without TA), indicating aggregation. Static quenching of tryptophan residues within the protein hydrophobic folds was observed. Increasing TA levels also enhanced protein thermal stability. Over 50% reduction in free amino groups of LPTA 0.5%, relative to LP, was observed after pepsin digestion. Cleavage specificity of pepsin and peptidomic profile of LP were modified by the presence of TA in LPTA 0.5%. This study showed that 0.5% w/v TA induced protein aggregation and reduced LP digestibility by hindering the accessibility of pepsin to the protein network, thus modifying the profile of released peptides.

It has been recognized that, next to dietary fibre and proteins, gut microbiota can metabolize lipids producing bioactive metabolites. However, the metabolism of dietary lipids by human gut microbiota has been poorly explored so far. This study aimed to examine the change in lipids, particularly linoleic acid (LA), induced by the chemical form of lipids and the presence of the plant matrix. Short-chain fatty acid (SCFA) production was monitored to get an insight into microbial activity. Free LA, glyceryl trilinoleate and soybean oil as well as digested intact (DS) and broken (BS) soybean cells were subjected to in vitro fermentation using human faecal inoculums. Confocal microscopy was used to visualize the soybean cell integrity. Three LA metabolites, including two conjugated fatty acids (CLAs, 9z,11e and 9e,11e) and 12hydroxy, 9z C18:1, were identified and monitored. Free LA addition improved the LA metabolite production but reduced SCFA concentrations compared to trilinoleate and soybean oil. Breaking cell integrity had impacts on CLA, hydroxy C18:1 and SCFA production and free fatty acid release within the first 24 h of fermentation, but this effect vanished with time. In contrast, soybean oil only increased free LA release and hydroxy C18:1 production. The content of several FAs decreased during fermentation suggesting a substantial conversion in microbial metabolites. Besides, LA metabolites were also identified in the fermentation pellets suggesting the incorporation of microbial FA metabolites into bacterial cells. This study expands our understanding of microbial metabolism of dietary lipids with a special emphasis on the role of food- and diet-related factors.

The aryl hydrocarbon receptor (AhR) plays an important role in intestinal homeostasis, and some microbial metabolites of tryptophan are known AhR agonists. In this study, we assessed the impact of tryptophan supplementation on the formation of tryptophan metabolites, AhR activation, and microbiota composition in the simulator of the human intestinal microbial ecosystem (SHIME). AhR activation, microbial composition, and tryptophan metabolites were compared during high tryptophan supplementation (4 g/L tryptophan), control, and wash-out periods. During tryptophan supplementation, the concentration of several tryptophan metabolites was increased compared to the control and wash-out period, but AhR activation by fermenter supernatant was significantly decreased. This was due to the higher levels of tryptophan, which was found to be an antagonist of AhR signaling. Tryptophan supplementation induced most microbial changes in the transverse colon including increased relative abundance of lactobacillus. We conclude that tryptophan supplementation leads to increased formation of AhR agonists in the colon.