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Despite significant advances in reconstructing genome-scale metabolic networks, the understanding of cellular metabolism remains incomplete for many organisms. A promising approach for elucidating cellular metabolism is analysing the full scope of enzyme promiscuity, which exploits the capacity of enzymes to bind to non-annotated substrates and generate novel reactions. To guide time-consuming costly experimentation, different computational methods have been proposed for exploring enzyme promiscuity. One relevant algorithm is PROXIMAL, which strongly relies on KEGG to define generic reaction rules and link specific molecular substructures with associated chemical transformations. Here, we present a completely new pipeline, PROXIMAL2, which overcomes the dependency on KEGG data. In addition, PROXIMAL2 introduces two relevant improvements with respect to the former version: i) correct treatment of multi-step reactions and ii) tracking of electric charges in the transformations. We compare PROXIMAL and PROXIMAL2 in recovering annotated products from substrates in KEGG reactions, finding a highly significant improvement in the level of accuracy. We then applied PROXIMAL2 to predict degradation reactions of phenolic compounds in the human gut microbiota. The results were compared to RetroPath RL, a different and relevant enzyme promiscuity method. We found a significant overlap between these two methods but also complementary results, which open new research directions into this relevant question in nutrition.

This work was supported by the “Plan propio de Investigaci´on y Transferencia” of the University of Granada under the program “Intensificaci´on de la Investigaci´on, modalidad B′′ granted to Jos´e A. Rufi´an-Henares. This work is part of the doctoral thesis of Daniel Hinojosa-Nogueira conducted within the context of the “Program of Nutrition and Food Sciences” at the University of Granada., Increasing food security is one of the Sustainable Development Goals. One of the main risks in food is the increase in food contaminants. Processing methods, such as the addition of additives or heat treatment, influence contaminant generation and increase their levels in food. The aim of the present study was to create a database using a methodology similar to that of food composition databases but with a focus on potential food contaminants. CONT11 collects information on 11 contaminants: hydroxymethyl-2-furfural, pyrraline, Amadori compounds, furosine, acrylamide, furan, polycyclic aromatic hydrocarbons, benzopyrene, nitrates, nitrites and nitrosamines. This is collected for more than 220 foods obtained from 35 different data sources. A food frequency questionnaire validated for use with children was used to validate the database. Contaminant intake and exposure in 114 children aged 10–11 years were estimated. Outcomes were within the range of values described by other studies, confirming the usefulness of CONT11. This database will allow nutrition researchers to go a step further in assessing dietary exposure to some food components and the association of this with disease, whilst also informing strategies to reduce exposure., Universidad de Granada

Background Dietary interventions are likely tools for modulation of the gut microbiota but the large inter-individual variability in gut microbiota composition leads to different host responsiveness and the impact of a particular food cannot be assessed. In contrast, in vitro fermentation models allow characterization of the fecal microbiota when fermenting a large number of different foods. Furthermore, cooking methods also directly influence the effects of food on gut microbiota composition. The aim of this study was to investigate the gut microbiota growing on representative foods of the Mediterranean and Western diets as well as the influence of cooking methods using in vitro fermentations. Results We performed in vitro digestions and fermentations of 55 foods, raw or cooked using up to 5 cooking methods, for a total of 159 combinations, employing fecal material from three healthy adults as inoculum. The composition of the bacterial communities was determined by sequencing the 16S rRNA gene. Foods derived from plants or animals had significantly different impacts on the abundances of bacterial taxa. Animal and vegetable fats, fish and dairy products led to the greatest shifts in microbial composition. Specifically, an increase in the beneficial bacteria Faecalibacterium, Blautia and Roseburia was identified in animal and vegetable fats. However, butter, dairy products and fish also resulted in higher abundances of Lachnoclostridium, which has been associated to several diseases. With respect to cooking methods, only frying and roasting had strong and common effects across all food categories. In general, fried foods showed more differences than other cooking methods, and Ruminococcus was particularly responsive to the cooking method employed. Conclusions Despite substantial differences in baseline microbiota composition, some shared effects were detected across the three analyzed individuals, such as the substantial impact of high-fat foods on the abundance of health-relevant bacteria. Cooking methods effects on the gut microbiota resulted to be highly individualized and food-dependent, making them challenging to investigate and integrate into personalized diet. Further characterization of the responses of the fermentative microbiota to food-cooking method combinations will enable the refinement of dietary interventions aimed at gut microbiota modulation, paving the way towards personalized nutrition.

BACKGROUND Due to its influence on health, access to a good diet is one of the great objectives of the health services in many countries. There are many electronic services that offer advice on diet, recommending specific foods or recipes. Additionally, as information processing techniques advance, options to tackle a multi-factorial and individualized nutritional recommendation also increase in number, allowing the recommendation of complete menus taking into account several parameters. OBJECTIVE In this article we present and validate a personalized nutrition system based on an application (APP) for smart devices with the capacity to offer an adaptable menu to the user. METHODS The APP was developed following a structured recommendation generation scheme, where the characteristics of the menus of 20 users were evaluated. From these, a user profile was developed with their nutritional requirements and menus were generated for 2 weeks. These menus were evaluated by comparing their mean nutritional content versus the mean nutrient composition retrieved from dietary records. RESULTS The generated menus showed great similarity to those obtained from the user dietary questionnaires. However, the generated menus showed less variability regarding the amounts of micronutrients reached. This lower variability was accompanied by higher quantities of most of the micronutrients tested in the user menus. The macronutrient deviations were also corrected in the generated menus, offering a better adaptation to the biometric parameters provided by the users. CONCLUSIONS The presented system is a good tool for the generation of menus that are adapted to the user characteristics. It is therefore a starting point to carry out nutritional interventions where it is necessary to control the amount of nutrients. These nutritional interventions will be important to validate other modules of the system. CLINICALTRIAL ISRCTN63745549 INTERNATIONAL REGISTERED REPORT RR2-https:// doi.org/10.3390/foods11101480

This work was supported by the European Research Commission (Research Executive Agency) under the research project Stance4Health under Grant Contract No 816303 and by the Plan propio de Investigación y Transferencia of the University of Granada under the program “Intensificación de la Investigación, modalidad B”., The healthy status of human beings is associated with an appropriate nutritional status in Zn, which must firstly be bioavailable. We measured the total Zn amount and its bioaccesibility in raw foods and after cooking by common culinary techniques. These foods were submitted to an in vitro digestion and fermentation with faecal inocula from healthy adults and children to evaluate Zn bioaccesibility in the small and large intestine. Mean total Zn amount provided by foods was 8.080 μg/g. Zn amount released from food in the small intestine was significantly different among several food groups and lower in raw vegetal foods compared to cooked ones (frying, roasting and grilling; p < 0.05); the same behaviour was found in the large intestine for healthy children. Zn bioaccesibility in the large intestine varied statistically according to the subjects’ idiosyncrasies, and was higher in healthy children (p < 0.05) probably due to growth demands and different composition of the colonic microbiota. In healthy adults and children, the bioaccesible fractions were 33.0 ± 20.4 % for the small intestine, 16.4 ± 22.0 and 59.6 ± 29.9% for the large one, and the non-bioaccessible ones 50.6 ± 19.9 and 7.4 ± 9.1%, respectively., European Research Commission 816303, Plan propio de Investigación y Transferencia of the University of Granada, Universidad de Granada UGR

This work was supported by the European Research Commission (Research Executive Agency) under the research project Stance4Health under Grant (Contract No 816303) and by the 'Plan propio de Investigacion y Transferencia' of the University of Granada under the programme 'Intensificacion de la Investigacion, modalidad B' granted to Jose A. Rufian-Henares., Objective: Polyphenols are antioxidant compounds with an impact on different health factors. Thus, it is important to have precise tools to estimate the intake of polyphenols. This study focuses on the development of an intuitive tool to estimating the intake of dietary total polyphenols. Design: The tool was developed in a spreadsheet to improve accessibility and use. It is divided into six different meals for each of the 7 d with a similar format to 24-h diet recalls. The total polyphenol values of 302 foods were included and the possibility of own values. Setting: Framework of the European project Stance4Health, Granada, Spain. Participants: This tool was tested on 90 participants in different stages of life (girls, women and pregnant women). Ages ranged from 10 to 35 years. Results: The total polyphenol intake obtained was of 1790 629 mg polyphenols/d. The highest consumption of polyphenols was observed in pregnant women (2064 mg/d). Polyphenols intake during the weekend was lower for the three groups compared to the days of the week. The results were comparable with those of other studies. Conclusions: The current tool allows the estimation of the total intake of polyphenols in the diet in a fast and easy way. The tool will be used as a basis for a future mobile application., European Research Commission (Research Executive Agency) under the research project Stance4Health 816303

The prevalence of obesity has been increasing in children over the last few decades, becoming a concern for health professionals and governments. Gut microbial community structure in obese people have been found to differ from that of lean subjects for some taxa which could result in different production of microbial metabolites. The aim of the present work was to study whether the gut microbiota from obese children extracts a different concentration of antioxidant capacity than the gut microbiota from lean children. For this purpose, different foods were in vitro digested and in vitro fermented using fecal material from obese and lean children. FRAP, DPPH and Folin-Ciocalteu methods were used to measure the antioxidant capacity released during digestion and fermentation. Overall, when using lean gut microbiota, antioxidant capacity released was higher when measured via DPPH and FRAP. Moreover, according to DPPH results, lean gut microbiota could potentially release more antioxidant power from vegetables than from animal products, while obese gut microbiota did the opposite. On the contrary, with the FRAP method obese gut microbiota released higher levels of antioxidant power from plant products than from animal products, but the final antioxidant capacity was still lower than that released by lean gut microbiota. Therefore, these results reflect that the total antioxidant capacity of foods is influenced by the gut microbiota, although whether that antioxidant capacity is released from plant or animal products can be slightly influenced by the method used for analysis., This work was supported by the European Research Commission (Research Executive Agency) under de research project Stance4Health under Grant (Contract No 816303) granted to José Á. Rufián Henares and by the Plan Propio de Investigación y Transferencia of the University of Granada under the program “Intensificación de la Investigación, modalidad B”, granted to José Á. Rufián Henares.

CRediT authorship contribution statement Emanuele Ugo Garzarella: Methodology, Data analysis, Data curation, Software; Beatriz Navajas-Porras: Research design, Methodology, Data analysis, Software; Sergio P´erez-Burillo: Writing manuscript, Research design, Methodology, Data analysis; Hammad Ullah: Writing manuscript; Cristina Esposito: Methodology, Data analysis; Cristina Santarcangelo: Methodology, Data analysis; Daniel Hinojosa-Nogueira: Research design, Data analysis; Silvia Pastoriza: Research design; Vincenzo Zaccaria: Research design; Jianbo Xiao: Writing manuscript; Jos´e Angel Rufian-Henares: Writing manuscript, Research design, Obtained funding; Maria Daglia: Conceptualization, Writing manuscript., Author Contributions S.P.B., H.U., J.A.R.H., J.X., and M.D. wrote or contributed to the writing of the manuscript. S.P.B., J.A.R.H., B.N.P., D.H.N., V.Z., and S.P. participated in research design. S.P.B., E.U.G., C.E., C.S., B.N.P., D.H.N. conducted experiments and performed data analysis. J.A.R.H. obtained funding for the study. All authors have read and agreed to the published version of the manuscript., Introduction: A large body of evidence suggests that propolis exerts antioxidant, anti-inflammatory, and antimicrobial activities, mostly ascribed to its polyphenol content. Growing evidence suggests that propolis could modulate gut microbiota exerting a positive impact on several pathological conditions. The aim of this study was to determine the in vitro impact of a poplar-type propolis extract with a standardized polyphenol content, on the composition and functionality of gut microbiota obtained from fecal material of five different donors (healthy adults, and healthy, obese, celiac, and food allergic children). Methods: The standardized polyphenol mixture was submitted to a simulated in vitro digestion-fermentation process, designed to mimic natural digestion in the human oral, gastric, and intestinal chambers. The antioxidant profile of propolis before and after the digestion-fermentation process was determined. 16 S rRNA amplicon next-generation sequencing (NGS) was used to test the effects on the gut microbiota of propolis extract. The profile of the short-chain fatty acids (SCFA) produced by the microbiota was also investigated through a chromatographic method coupled with UV detection. Results: In vitro digestion and fermentation induced a decrease in the antioxidant profile of propolis (i.e., decrease of total polyphenol content, antiradical and reducing activities). Propolis fermentation exhibited a modulatory effect on gut microbiota composition and functionality of healthy and diseased subjects increasing the concentration of SCFA. Conclusions: Overall, these data suggest that propolis might contribute to gut health and could be a candidate for further studies in view of its use as a prebiotic ingredient., Plan Propio de Investigación y Transferencia of the University of Granada, Spain under the program “Intensificación de la Investigación, modalidad B

Funding: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 816303 and from the Plan Propio de Investigación y Transferencia of the University of Granada under the program “Intensificación de la Investigación, modalidad B”., Acknowledgments: This work is part of the doctoral thesis of Daniel Hinojosa-Nogueira conducted within the context of the “Program of Nutrition and Food Sciences” at the University of Granada and part of the doctoral thesis of Bartolome Ortiz-Viso conducted within the context of the “Program of Information and Communication technologies” at the University of Granada., Access to good nutritional health is one of the principal objectives of current society. Several e-services offer dietary advice. However, multifactorial and more individualized nutritional recommendations should be developed to recommend healthy menus according to the specific user’s needs. In this article, we present and validate a personalized nutrition system based on an application (APP) for smart devices with the capacity to offer an adaptable menu to the user. The APP was developed following a structured recommendation generation scheme, where the characteristics of the menus of 20 users were evaluated. Specific menus were generated for each user based on their preferences and nutritional requirements. These menus were evaluated by comparing their nutritional content versus the nutrient composition retrieved from dietary records. The generated menus showed great similarity to those obtained from the user dietary records. Furthermore, the generated menus showed less variability in micronutrient amounts and higher concentrations than the menus from the user records. The macronutrient deviations were also corrected in the generated menus, offering a better adaptation to the users. The presented system is a good tool for the generation of menus that are adapted to the user characteristics and a starting point to nutritional interventions., European Union’s Horizon 2020 research and innovation programme under grant agreement No 816303, Plan Propio de Investigación y Transferencia of the University of Granada under the program “Intensificación de la Investigación, modalidad B”

The European Commission funded project Stance4Health (S4H) aims to develop a complete personalised nutrition service. In order to succeed, sources of information on nutritional composition and other characteristics of foods need to be as comprehensive as possible. Food composition tables or databases (FCT/FCDB) are the most commonly used tools for this purpose. The aim of this study is to describe the harmonisation efforts carried out to obtain the Stance4Health FCDB. A total of 10 FCT/FCDB were selected from different countries and organizations. Data were classified using FoodEx2 and INFOODS tagnames to harmonise the information. Hazard analysis and critical control points analysis was applied as the quality control method. Data were processed by spreadsheets and MySQL. S4H’s FCDB is composed of 880 elements, including nutrients and bioactive compounds. A total of 2648 unified foods were used to complete the missing values of the national FCDB used. Recipes and dishes were estimated following EuroFIR standards via linked tables. S4H’s FCDB will be part of the smartphone app developed in the framework of the Stance4Health European project, which will be used in different personalized nutrition intervention studies. S4H FCDB has great perspectives, being one of the most complete in terms of number of harmonized foods, nutrients and bioactive compounds included.

Coffee is one of the most consumed beverages and has been linked to health in different studies. However, green and roasted coffees have different chemical composition and therefore their health properties might differ as well. Here, we study the effect of in vitro digestion-fermentation on the antioxidant capacity, phenolic profile, production of short-chain fatty acids (SCFAs), and gut microbiota community structure of green and roasted coffee brews. Roasted coffees showed higher antioxidant capacity than green coffees, with the highest level achieved in fermented samples. Polyphenol profile was similar between green and roasted coffees in regular coffee brews and the digested fraction, but very different after fermentation. Production of SCFAs was higher after fermentation of green coffee brews. Fermentation of coffee brews by human gut microbiota led to different community structure between green and roasted coffees. All these data suggest that green and roasted coffees behave as different types of food.

Dry-fermented sausages are an important and abundant component of the diet of many people. Improving their composition and thus their potential health effects is therefore important. Here we quantified the antioxidant capacity, short chain fatty acids (SCFAs) production, and gut microbiota structure of different salami formulations after in vitro digestion and subsequent fermentation with human gut microbiota. The addition of different types of fiber (citrus fiber, arabinogalactan, and inulin), a probiotic Lactobacillus rhamnosus, and an herbal extract to the salami formulation was tested. Incorporating any dietary fiber into salami formulation increased sausage antioxidant capacity and the amount of SCFAs produced during microbiota fermentation. These effects were highest for salami with citrus fiber and citrus fiber with herbal extract. Presence of fiber in salami also led to an altered gut microbiota structure. Citrus fiber and arabinogalactan but not inulin promoted an increase in the abundance of several known polysaccharide degrading genera and resulted in a reduction in the abundance of Escherichia, a bacterial genus known to contain many human intestinal pathogens. Overall, the addition of dietary fiber to salami formulation prior to curing improved beneficial health markers of this food product.

One of the most consumed beverages around the world is tea, but little is known about how tea quality can be monitored during storage and processing. Thus, the objective of this research was to study the usefulness of furosine and 5-hydroxymethylfurfural (HMF) content -two Maillard reaction markers-as quantitative parameters that control tea processing and storage. Two different experiments were carried out: one using green and black teas (processed at laboratory scale) and another one using commercial green, white, black and red teas that were under storage for one year (shelf life) and under accelerated conditions (55 °C at 40% of humidity for 3 months). The samples were analyzed for the content of furosine, HMF, and free and total lysine. The combination of HMF and furosine was useful as an indicator to control tea processing and storage regardless the type of tea. HMF and furosine are useful chemical indicators (when combined) to monitor tea quality during processing and storage. Furosine analysis is especially sensitive to control the first drying steps, while HMF reflects those changes occurred in the last tea processing steps.

This work is part of the doctoral thesis of Lida Yaneth Maldonado-Mateus conducted within the context of the "Program of Nutrition and Food Sciences" at the University of Granada. This work was supported by the "Plan propio de Investigacion y Transferencia" of the University of Granada under both programs "Intensificacion de la Investigacion, modalidad B" granted to Jose A. Rufian-Henares and the postdoctoral program "Perfeccionamiento de Doctores" in the case of Sergio Perez-Burillo, and by the European Research Commission (Research Executive Agency) under the research project Stance4Health under a grant (Contract No. 816303) to Jose A. Rufian-Henares., Cocoa is a highly consumed food with beneficial effects on human health. Cocoa roasting has an important influence on its sensory and nutritional characteristics; therefore, roasting could also play a role in cocoa bioactivity. Thus, the aim of this paper is to unravel the effect of cocoa roasting conditions on its antioxidant capacity and modifications of gut microbiota after in vitro digestion-fermentation. HMF and furfural, chemical markers of non-enzymatic browning, were analyzed in unroasted and roasted cocoa powder at different temperatures, as well as different chocolates. The antioxidant capacity decreased with roasting, most probably due to the loss of phenolic compounds during heating. In the case of the evaluated chocolates, the antioxidant capacity was 2–3 times higher in the fermented fraction. On the other hand, HMF and furfural content increased during roasting due to increasing temperatures. Moreover, unroasted and roasted cocoa powder have different effects on gut microbial communities. Roasted cocoa favored butyrate production, whereas unroasted cocoa favored acetate and propionate production in a significant manner. In addition, unroasted and roasted cocoa produced significantly different gut microbial communities in terms of composition. Although many bacteria were affected, Veillonella and Faecalibacterium were some of the most discriminant ones; whereas the former is a propionate producer, the latter is a butyrate producer that has also been linked to positive effects on the inflammatory health of the gut and the immune system. Therefore, unroasted and roasted cocoa (regardless of the roasting temperature) promote different bacteria and a different SCFA production., "Plan propio de Investigacion y Transferencia" of the University of Granada, European Research Commission (Research Executive Agency) under the research project Stance4Health 816303

This work was supported by the European Research Commission (Research Executive Agency) under de research project Stance4Health (Grant contract N degrees 816303) and by the Plan propio de Investigacion y Transferencia of the University of Granada under the program "Intensificacion de la Investigacion, modalidad B". This manuscript was also supported by the posdoctoral fellowship granted to S.P.B. under the University of Granada program "Perfeccionamiento de Doctores"., Green tea can influence the gut microbiota by either stimulating the growth of specific species or by hindering the development of detrimental ones. At the same time, gut bacteria can metabolize green tea compounds and produce smaller bioactive molecules. Accordingly, green tea benefits could be due to beneficial bacteria or to microbial bioactive metabolites. Therefore, the gut microbiota is likely to act as middle man for, at least, some of the green tea benefits on health. Many health promoting effects of green tea seems to be related to the inter-relation between green tea and gut microbiota. Green tea has proven to be able to correct the microbial dysbiosis that appears during several conditions such as obesity or cancer. On the other hand, tea compounds influence the growth of bacterial species involved in inflammatory processes such as the release of LPS or the modulation of IL production; thus, influencing the development of different chronic diseases. There are many studies trying to link either green tea or green tea phenolic compounds to health benefits via gut microbiota. In this review, we tried to summarize the most recent research in the area., European Research Commission (Research Executive Agency) under de research project Stance4Health 816303, Plan propio de Investigacion y Transferencia of the University of Granada under the program "Intensificacion de la Investigacion, modalidad B", University of Granada program "Perfeccionamiento de Doctores"

The gastrointestinal digestion of food and further gut microbial activity render a myriad of different molecules that could be responsible for the biological activities that are classically assigned to their parent compounds. This has been previously shown for some phytochemicals whose antioxidant capacity was either increased or decreased after being metabolized by gut microbes. Whether a global antioxidant capacity that is extracted from food is determined by the gut microbial community structure is still not well described. In the present study, we in vitro digested and fermented 48 different foods that were submitted to different culinary treatments using the stools of lean children, obese children, celiac children and children with an allergy to cow’s milk proteins. Their antioxidant capacities were assessed with the DPPH and FRAP assays, and the percentage that each food contributed to their daily antioxidant intake as well as their antioxidant capacity by portion size was inferred. Overall, cereals, fruits and vegetables displayed a higher contribution to their daily antioxidant intake, while tubers, fish and meat exhibited a higher antioxidant capacity by serving size. The food that was fermented in the lean children’s and those children that were allergic to cow’s milk protein’s fecal material, showed a higher antioxidant capacity, which could imply that there is a larger role of the gut microbiota in this area.

This work is part of the doctoral thesis of Daniel Hinojosa- Nogueira conducted within the context of the “Program of Nutrition and Food Sciences” at the University of Granada. This work was supported by the “Plan propio de Investigación y Transferencia” of the University of Granada under the program “Intensificación de la Investigación, modalidad B” granted to José A. Rufián-Henares., Tea is one of the most consumed beverages around the world and as such, it is constantly the object of novel research. This review focuses on the research performed during the last five years to provide an updated view of the current position of tea regarding human health. According to most authors, tea health benefits can be traced back to its bioactive components, mostly phenolic compounds. Among them, catechins are the most abundant. Tea has an important antioxidant capacity and anti-inflammatory properties, which make this beverage (or its extracts) a potential aid in the fight against several chronic diseases. On the other hand, some studies report the possibility of toxic effects and it is advisable to reduce tea consumption, such as in the last trimester of pregnancy. Additionally, new technologies are increasing researchers' possibilities to study the effect of tea on human gut microbiota and even against SARS CoV-2. This beverage favours some beneficial gut microbes, which could have important repercussions due to the influence of gut microbiota on human health., "Plan propio de Investigacion y Transferencia" of the University of Granada under the program "Intensificacion de la Investigacion, modalidad B"

Supplementary information The online version contains supplementary material available at https://doi.org/10.1038/s41596-021-00537-x., This study was supported by the EU project Stance4Health (contract no. 816303) and by the Plan propio de Investigación y Transferencia of the University of Granada under the program ‘Intensificación de la Investigación, modalidad B’ to J.A.R.-H., Knowledge of the effect of foods on gut microbiota composition and functionality is expanding. To isolate the effect of single foods and/or single nutrients (i.e., fiber, polyphenols), this protocol describes an in vitro batch fermentation procedure to be carried out after an in vitro gastrointestinal digestion. Therefore, this is an extension of the previous protocol described by Brodkorb et al. (2019) for studying in vitro digestion. The current protocol uses an oligotrophic fermentation medium with peptone and a high concentration of fecal inoculum from human fecal samples both to provide the microbiota and as the main source of nutrients for the bacteria. This protocol is recommended for screening work to be performed when many food samples are to be studied. It has been used successfully to study gut microbiota fermentation of different foodstuffs, giving insights into their functionality, community structure or ability to degrade particular substances, which can contribute to the development of personalized nutrition strategies. The procedure does not require a specific level of expertise. The protocol takes 4–6 h for preparation of fermentation tubes and 20 h for incubation., EU project Stance4Health (contract no. 816303), Plan propio de Investigación y Transferencia of the University of Granada under the program ‘Intensificación de la Investigación, modalidad B

The main objective of this work was to evaluate the effect that several plant extracts (currently sold as functional ingredients) have on gut microbiota community structure and functionality. Plant extracts were submitted to an in vitro digestion and fecal fermentation. Overall, plant extracts showed a marked inhibitory activity when compared to basal conditions. However, they also favored the growth of some bacteria such as Coprococcus and Butyricimonas, two butyrate producers. Especially interesting was tea extract which inhibited the growth of the genus Escherichia/Shigella, known to involve species related with gastrointestinal disorders. Additionally, tea extract increased the growth of Faecalibacterium, a known butyrate producer. Regarding short chain fatty acids production, while plant extracts reduced acetate production, butyrate was increased for most samples, especially tea extract. Propionate production was less affected in comparison with basal conditions. Fermentation by gut microbiota also modified the antioxidant capacity (assessed via DPPH, FRAP and Folin-Ciocalteu methods)., Spanish Ministry of Economy and Competitiveness AGL2014-53895-R, European Union (EU)

Understanding how diet and gut microbiota interact in the context of human health is a key question in personalized nutrition. Genome-scale metabolic networks and constraint-based modeling approaches are promising to systematically address this complex question. However, when applied to nutritional questions, a major issue in existing reconstructions is the lack of information about degradation pathways of relevant nutrients in the diet that are metabolized by the gut microbiota. Here, we present AGREDA, an extended reconstruction of the human gut microbiota metabolism for personalized nutrition. AGREDA includes the degradation pathways of 231 nutrients present in the human diet and allows us to more comprehensively simulate the interplay between food and gut microbiota. We show that AGREDA is more accurate than existing reconstructions in predicting output metabolites of the gut microbiota. Finally, using AGREDA, we established relevant metabolic differences among clinical subgroups of Spanish children: lean, obese, allergic to foods and celiac.

The antioxidant capacity of food influences its shelf life and human health. To determine this parameter, the corresponding antioxidant species must first be extracted. Current methods don't adequately address this issue since they rely on extractions with organic solvents or on in vitro digestion without a subsequent fermentation. We present an improved protocol to determine the global antioxidant response of foods (GAR+) including both in vitro digestion and fermentation. All samples should be fermented with the same fresh faecal inoculum in order to decrease variability. In addition, the use of a pool of faeces from healthy donors is strongly recommended to improve repeatability. Although most antioxidant capacity is achieved after digestion, in some foods fermentation plays a role. Thus, the GAR+ method provides reliable values of the antioxidant capacity of foods that are closer to their in vivo activity by including the effects of gut microbiota over non-digested nutrients.

Spent coffee grounds are a byproduct with a large production all over the world. The aim of this study was to explore the effects of a simulated digestion-fermentation treatment on hydrolyzed spent coffee grounds (HSCG) and to investigate the antioxidant properties of the digestion and fermentation products in the human hepatocellular carcinoma HepG2 cell line. The potentially bioaccessible (soluble) fractions exhibited high chemoprotective activity in HepG2 cells against oxidative stress. Structural analysis of both the indigestible (insoluble) and soluble material revealed partial hydrolysis and release of the lignin components in the potentially bioaccessible fraction following simulated digestion-fermentation. A high prebiotic activity as determined from the increase in Lactobacillus spp. and Bifidobacterium spp. and the production of short-chain fatty acids (SCFAs) following microbial fermentation of HSCG was also observed. These results pave the way toward the use of HSCG as a food supplement., This work was supported by the Project AGL2014-53895-R from the Spanish Ministry of Economy and Competitiveness and the European Fund of Regional Development (FEDER).

Green and white teas are some of the most consumed beverages in the world, especially due to their inherent health properties such as prevention of cardiovascular and neurodegenerative pathologies, diabetes, body weight control, among others. Such properties are related with the presence on tea beverage of different bioactive compounds like catechins, caffeine, theophylline or minerals. The extraction of catechins is related with the final antioxidant capacity of the beverages, which in turn correlates with many parameters such us time/temperature of infusion, particle size, number of extractions, storage time, exposition to light, etc.

A human intervention in 24 healthy volunteers was performed to test the potential health benefits of a fermented salami with a probiotic Lactobacillus rhamnosus HN001 and added citrus fiber. Anthropometric measurements and blood biochemistry did not show any significant differences between pre- and post-intervention during 4 weeks with a daily intake of 30 g of salami, neither with regular salami (control group) nor with reformulated salami (intervention group). However, the inflammatory markers CRP and TNFα decreased significantly after intervention, suggesting a less inflammatory environment after reformulated salami consumption. Antioxidant plasmatic markers also improved within the intervention group. Butyrate production was significantly increased after reformulated salami consumption. Gut microbiota community structure, however, was not significantly shaped by neither regular nor reformulated salami. After the intervention with probiotic salami, L. rhamnosus was detected by quantitative polymerase chain reaction (qPCR) in all samples of the intervention group but not in the control group, showing probiotic effect., This trial was supported by project AVANZA-S from the Spanish Centre for the Development of Industrial Technology (CDTI). It was also supported by a Spanish predoctoral fellowship F.P.U. (ref.: FPU14/ 01192) for S. Perez-Burillo from the Spanish Government

The aim of this work was to study the evolution of quality parameters, fatty acid composition, antioxidant capacity and total phenolic content of olive oil obtained from two olive varieties (Manzanilla and Picual) with different maturation. Antioxidant capacity and total phenolic content were measured after submitting the olive oil to in vitro digestion and fermentation to mimic physiological conditions. Quality parameters were always within the legal limits to be called "Extra Virgin Olive Oil". Antioxidant capacity, total phenolic content, saturated fatty acids and monounsaturated fatty acids (MUFA) decreased along maturation, whereas polyunsaturated fatty acids (PUFA) increased in both varieties. Manzanilla showed higher PUFA content, whereas Picual had higher MUFA concentration, antioxidant capacity and total phenolic content. The fermented fraction of olive oil displayed a higher antioxidant capacity. Finally, the statistical approach demonstrated that the type of variety is more important than collection date regarding fatty acid composition and antioxidant capacity.

A total of 42 different rums currently marketed in Spain were analyzed to study the effect of aging time and manufacturing steps (filtration, addition of additives or spices, solera aging method, use of different types of aging barrels) on several parameters: color, non-enzymatic browning, antioxidant capacity and phenolic profile. Different analytical techniques to obtain a broader descriptions of the samples were employed: absorption and UV-vis spectrophotometry, antioxidant capacity (DPPH, FRAP, ABTS methods), total phenols and HPLC to detect individual phenolic and furanic compounds. Results showed that spectrophotometric techniques could potentially be used to detect adulteration and frauds, as well as to differentiate rums by aging time. Those rums aged longer, especially those aged in oak barrels that had previously contained Bourbon or wine, showed higher phenolic content, antioxidant capacity and concentration of furanic compounds. Filtration results in the loss of antioxidant compounds while adding spices increases their concentration in rums.

Melanoidins are an important component of the human diet (average consumption 10 g/day), which escape gastrointestinal digestion and are fermented by the gut microbiota. In this study melanoidins from different food sources (coffee, bread, beer, balsamic vinegar, sweet wine, biscuit, chocolate, and breakfast cereals) were submitted to an in vitro digestion and fermentation process, and their bioactivity was assessed. Some melanoidins were extensively used by gut microbes, increasing production of short chain fatty acids (mainly acetate and lactate) and favoring growth of the beneficial genera Bifidobacterium (bread crust, pilsner and black beers, chocolate and sweet wine melanoidins) and Faecalibacterium (biscuit melanoidins). Quantification of individual phenolic compounds after in vitro fermentation allowed their identification as microbial metabolites or phenolics released from the melanoidins backbone (specially pyrogallol, 2-(3,4-dihydroxyphenyl)acetic and 3-(3,4-dihydroxyphenyl)propionic acids). Our results also showed that antioxidant capacity of melanoidins is affected by gut microbiota fermentation.

Coffee is one of the most consumed beverages around the world, and as a consequence, spent coffee grounds are a massively produced residue that is causing environmental problems. Reusing them is a major focus of interest presently. We extracted mannooligosaccharides (MOS) from spent coffee grounds and submitted them to an in vitro fermentation with human feces. Results obtained suggest that MOS are able to exert a prebiotic effect on gut microbiota by stimulating the growth of some beneficial genera, such as Barnesiella, Odoribacter, Coprococcus, Butyricicoccus, Intestinimonas, Pseudoflavonifractor, and Veillonella. Moreover, short-chain fatty acids (SCFA) production also increased in a dose-dependent manner. However, we observed that 5-(hydroxymethyl)furfural, furfural, and polyphenols (which are either produced or released from the spent coffee grounds matrix during hydrolysis) could have an inhibitory effect on other beneficial genera, such as Faecalibacterium, Ruminococcus, Blautia, Butyricimonas, Dialister, Collinsella, and Anaerostipes, which could negatively affect the prebiotic activity of MOS.

Cooking modifies food composition due to chemical reactions. Additionally, food composition shapes the human gut microbiota. Thus, the objective of this research was to unravel the effect of different food cooking methods on the structure and functionality of the gut microbiota. Common culinary techniques were applied to five foods, which were submitted to in vitro digestion-fermentation. Furosine, 5-(hydroxymethyl)furfural, and furfural were used as Maillard reaction indicators to control the heat treatment. Short-chain fatty acids production was quantified as indicator of healthy metabolic output. Gut microbial community structure was analyzed through 16S rRNA. Both food composition and cooking methods modified the microbiota composition and released short-chain fatty acids. In general, intense cooking technologies (roasting and grilling) increased the abundance of beneficial bacteria like Ruminococcus spp. or Bifidobacterium spp. compared to milder treatments (boiling). However, for some foods (banana or bread), intense cooking decreased the levels of healthy bacteria.

While a substantial amount of dietary fats escape absorption in the human small intestine and reach the colon, the ability of resident microbiota to utilize these dietary fats for growth has not been investigated in detail. In this study, we used an in vitro multivessel simulator system of the human colon to reveal that the human gut microbiota is able to utilize typically consumed dietary fatty acids to sustain growth. Gut microbiota adapted quickly to a macronutrient switch from a balanced Western diet-type medium to its variant lacking carbohydrates and proteins. We defined specific genera that increased in their abundances on the fats-only medium, including Alistipes, Bilophila, and several genera of the class Gammaproteobacteria. In contrast, the abundances of well-known glycan and protein degraders, including Bacteroides, Clostridium, and Roseburia spp., were reduced under such conditions. The predicted prevalences of microbial genes coding for fatty acid degradation enzymes and anaerobic respiratory reductases were significantly increased in the fats-only environment, whereas the abundance of glycan degradation genes was diminished. These changes also resulted in lower microbial production of short-chain fatty acids and antioxidants. Our findings provide justification for the previously observed alterations in gut microbiota observed in human and animal studies of high-fat diets. IMPORTANCE Increased intake of fats in many developed countries has raised awareness of potentially harmful and beneficial effects of high fat consumption on human health. Some dietary fats escape digestion in the small intestine and reach the colon where they can be metabolized by gut microbiota. We show that human gut microbes are able to maintain a complex community when supplied with dietary fatty acids as the only nutrient and carbon sources. Such fatty acid-based growth leads to lower production of short-chain fatty acids and antioxidants by community members, which potentially have negative health consequences on the host.

Vegetables are health-promoting foods due to their content on a wide range of phytochemicals, being involved in antioxidant protection. However, such bioactivity can be modified during cooking and also along the digestion-fermentation process. Thus, the aim of the paper is to establish a relation among the type of processing (raw, boiled, steamed, grilled, roasted, and fried), time of processing (raw, usual time and well-done), antioxidant capacity and the development of the Maillard reaction (measured though the analysis of furosine and HMF) of 23 widely consumed vegetables. Antioxidant capacity was measured with three methods (TEACABTS, TEACFRAP, TEACOH) after submitting vegetables to an in vitro digestion followed by and in vitro fermentation process. Furosine and HMF were useful indicators to control both cooking time and heat intensity of common vegetables, being correlated with antioxidant capacity. Those samples cooked with aggressive techniques (frying, grilling or breading) showed the higher antioxidant values.

Fruits are foods that contain plenty of vitamins, minerals and some bioactive phytochemicals like polyphenols. Thus, fruits may exert different functional properties on human health, some of which are directly related to their antioxidant capacity like cancer or atherosclerosis. Owing to globalization, consumers have a wide repertory of fruits throughout the year. Among them, tropical and subtropical fruits are steadily expanding, as well as the studies about them. In this sense, this timely review focused on the nutritional value and chemical composition of persimmon and kiwifruit, two tropical fruits with a protective role on different chronic diseases. Thus, this review focused mainly on the presence of bioactive compounds such as polyphenols, tannins, carotenoids, vitamin C and the different functional properties (i.e. antioxidant capacity, antithrombotic activity, decrease of plasmatic lipids, etc.) arising from the presence of such biologically active molecules. Finally, the effects of genotype and ripening stage on antioxidant capacity and the content of bioactive compounds in persimmon and kiwifruit are also discussed.

White tea is highly consumed due to its sensory properties and health benefits, although most scientific reports don't include the analysis of both properties. Therefore, the objective of the present study was to unravel the best brewing conditions for optimal extraction of the bioactive compounds and antioxidant capacity, while realising the best sensory properties. Infusions of eighty commercial teas (sold in bags or leaves) were obtained at different time-temperature ratios, studying bioactive compounds (caffeine and individual catechins), antioxidant capacity and sensory analysis. Brewing at 98 °C for 7 min was the best condition to obtain a high content of antioxidant polyphenols and pleasant sensory properties. Those teas sold in bags give rise to tea brews with almost double antioxidant capacity. In conclusion, it is very important to link sensory and chemical data to obtain optimal sensorial quality and the highest healthy properties in white tea infusions.

Many methods have been developed to measure the antioxidant capacity of foods under non physiological-relevant conditions. In this study, three methods (TEACOH, GEACRED and TEACAAPH) are developed to measure antioxidant capacity at physiological pH, using indigo carmine as a redox dye. TEACOH and TEACAAPH determine foodstuffs' scavenging capacity against hydroxyl (OH) and AAPH radicals, while the third method measures the global reducing capacity of the sample. The results obtained for commercial teas, commercial beverages containing tea as the main ingredient and different solid foods (spinach, onion, salami, etc.) were compared with well-established protocols. The new methods demonstrated good linearity-reproducibility, providing reliable data about the antioxidant capacity of foods under physiological-resembling conditions. The new methods were also useful for evaluating the antioxidant capacity of human plasma after acute intake of tea. The physiological-resembling conditions of these assays and the use of absorbance readings make them suitable for application by any laboratory.