Brewer´s spent grain as a potential source of antioxidants: characterization of extracts

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Impact of phlorotannin extracts from fucus vesiculosus on human gut microbiota

Recent studies indicate that plant polyphenols could be pointed as potential prebiotic candidates since they may interact with the gut microbiota, stimulating its growth and the production of metabolites. However, little is known about the fate of brown seaweeds’ phlorotannins during their passage throughout the gastrointestinal tract. This work aimed to evaluate the stability and bioaccessibility of Fucus vesiculosus phlorotannins after being submitted to a simulated digestive process, as well as their possible modulatory effects on gut microbiota and short-chain fatty acids production following a fermentation procedure using fecal inoculates to mimic the conditions of the large intestine. The stability of phlorotannins throughout the gastrointestinal tract was reduced, with a bioaccessibility index between 2 and 14%. Moreover, slight alterations in the growth of certain commensal bacteria were noticed, with Enterococcus spp. being the most enhanced group. Likewise, F. vesiculosus phlorotannins displayed striking capacity to enhance the levels of propionate and butyrate, which are two important short-chain fatty acids known for their role in intestinal homeostasis. In summary, this work provides valuable information regarding the behavior of F. vesiculosus phlorotannins along the gastrointestinal tract, presenting clear evidence that these compounds can positively contribute to the maintenance of a healthy gastrointestinal condition.info:eu-repo/semantics/publishedVersio

Prebiotic effects of olive pomace powders in the gut: In vitro evaluation of the inhibition of adhesion of pathogens, prebiotic and antioxidant effects

Supplementary data related to this article can be found at https:// doi.org/10.1016/j.foodhyd.2020.106312Olive pomace is a biowaste rich in polyphenols and insoluble dietary fibre with high potential to develop new value chains towards a sustainable and circular bioeconomy. Regarding gut health, olive pomace phenolics and insoluble dietary fibre (after possible fermentation) could act as antioxidants, antimicrobial and prebiotic agents. These potential beneficial effects on the gut were analysed for two powders from olive pomace: liquid-enriched powder (LOPP) - mostly source of phenolics - and pulp-enriched powder (POPP) - main source of insoluble dietary fibre. LOPP and POPP were subjected to an in vitro simulated gastrointestinal digestion followed by in vitro faecal fermentation. The undigested fraction retained in the colon was analysed regarding its potential antioxidant, antimicrobial and prebiotic effects. LOPP and POPP did not impact the gut microbiota diversity negatively, showing a similar ratio of Firmicutes/Bacteroidetes compared to a positive control (FOS). LOPP exhibit a positive (similar to FOS) effect on the Prevotella spp./Bacteroides spp. ratio. Both powders also promoted more the production of short-chain fatty acids (mainly acetate?>?butyrate?>?propionate) than FOS. Both powders showed also significant total phenolic content and oxygen radical absorbance capacity during faecal fermentation until 48?h. Besides that, these powders showed mucin-adhesion inhibition ability against pathogens, principally POPP against Bacillus cereus (22.03?±?2.45%) and Listeria monocytogenes (20.01?±?1.93%). This study demonstrates that olive pomace powders have prebiotic effects on microbiota, including the stimulation of short-chain fatty acids production, potential antioxidant and antimicrobial activity which could improve human gut health.Tˆania I. B. Ribeiro thanks the FCT - Fundação para a Ciência e Tecnologia, Portugal and Association BLC3 – Technology and Innovation Campus, Centre Bio R&D Unit for the PhD Grant SFRH/BDE/108271/2015. This work was supported by National Funds from FCT - Fundação para a Ciência e a Tecnologia, Portugal through the project MULTI-BIOREFINERY - SAICTPAC/0040/2015 (POCI-01-0145-FEDER- 016403). We would also like to thank the scientific collaboration under the FCT project UID/Multi/50016/2019.info:eu-repo/semantics/publishedVersio

Caracterização microbiológica de matérias primas e validação do binómio : tempo x temperatura de esterilização de preparados alimentares

Na indústria alimentar, a contaminação das matérias-primas e dos alimentos é um problema que deve ser controlado para garantir a segurança alimentar. Os frutos secos, o chocolate e o cacau são matérias-primas potencialmente perigosas pois estão, normalmente, contaminadas com bactérias e fungos. Frutos como as framboesas também têm uma elevada carga microbiana. Para se poder utilizar estes produtos como matérias-primas de preparados alimentares é necessário aplicar tratamentos de inativação microbiológica como, por exemplo, tratamentos térmicos. Dentro dos tratamentos térmicos utilizados incluem-se a pasteurização e a esterilização térmica. Em ambos, a temperatura e o tempo variam conforme o preparado e os microrganismos que podem estar lá presentes. A esterilização térmica permite a inativação de microrganismos produtores de esporos resistentes ao calor (sendo os mais perigosos nestes alimentos o Clostridium botulinum e o Bacillus cereus). Pretendeu-se com esta tese quantificar a carga microbiológica total e formadora de esporos, em matérias-primas de diferentes origens utilizadas pela Frulact e otimizar os binómios de tempo/temperatura utilizados na esterilização dos preparados, minimizando a sua contaminação. Utilizaram-se dois preparados (um de chocolate e outro de framboesa) onde se aplicaram três binómios diferentes a cada um deles (109ºC/10 minutos, 111ºC/10 minutos, 116ºC/10 minutos ao preparado de chocolate; 104ºC/10 minutos, 106ºC/8 minutos, 109ºC/10 minutos ao preparado de framboesa). Concluiu-se que o binómio utilizado na esterilização do preparado de chocolate (116ºC/10 minutos) é o indicado para a destruição dos microrganismos (Clostridium, Bacillus cereus) presentes nas matérias-primas do preparado. Por outro lado, verificou-se que o binómio utilizado na esterilização do preparado de framboesa (104ºC/10 minutos), não é suficiente para a destruição dos microrganismos. Sugere-se, assim, o binómio 106ºC/8 minutos pois mostrou-se mais eficaz na esterilização. Determinou-se também a carga microbiana termorresistente em matérias-primas ou preparados com interesse para a empresa.The contamination of raw materials and food products is an important issue to the food industry that needs to be controlled, in order to reach acceptable food safety standards. Dried fruits, chocolate and cocoa are potentially dangerous raw materials due to eventual contamination with bacteria, fungi and yeasts. Fruits such as raspberries also have a high microbiological load. In order to be able to utilize these ingredients in food preparations, the food industry must apply microbiological inactivation methods, such as heat treatment, to the food preparation. Within the heat treatments used, pasteurization and thermal sterilization are included. Time-temperature binomials vary according to the food preparation and microorganisms that may be present. The thermal sterilization allows the inactivation of spore forming bacteria (being the most dangerous Clostridium botulinum and Bacillus cereus). The aim of this thesis was to quantify the total microbiological and spore load of raw materials from different sources, used by Frulact and optimize time/temperature binomials used in the sterilization of food preparations. Two different food preparations were used, one of chocolate and another of raspberry, to which three different binomials were applied (109ºC/10 minutes, 111°C/10 minutes, 116°C/10 minutes to the chocolate preparation; 104ºC/10 minutes, 106ºC/8 minutes at 109ºC/10 minutes to the raspberry preparation). It was possible to conclude that the binomial used by Frulact for the sterilization of the chocolate preparation (116ºC/10 minutes) is efficient and thus appropriate for the destruction of microorganisms (Clostridium, Bacillus cereus) present in this raw material. On the other side, it was found that the binomial normally applied to the raspberry preparation (104°C/10 min) is not adequate for the sterilization of this product. The results obtained suggest that the 106ºC/8 minutes binomial is effective in this case. It was also determined the microbiological heat resistant load in raw materials or preparations with interest to the company

Desenvolvimento e caracterização de ingredientes funcionais através da valorização de drêche

Tese de doutoramento em Food Science and Technology and NutritionO principal objetivo desta tese foi explorar o valor do subproduto da produção de cerveja, a drêche, promovendo o princípio do desenvolvimento sustentável com a obtenção de ingredientes de valor acrescentado. Assim, a partir destes resíduos, foram realizadas extrações utilizando a técnica sólido-líquido, aquecimento óhmico e solventes utilizados na indústria alimentar (água e etanol) (para garantir a manutenção da integridade composicional, funcionalidade e segurança dos extratos bioativos obtidos). Todos os extratos hidroetanólicos obtidos pela extração sólido-líquido apresentaram alta capacidade antioxidante, e os maiores valores foram obtidos para o extrato 60% etanol:água (v/v). A identificação por HPLC mostrou que a catequina e a vanilina foram os principais compostos identificados com maior concentração (223.6 e 109.2 μg/g drêche, respetivamente) usando 60% etanol:água (v/v). Nos ensaios de atividade biológica os extratos mostraram-se multifuncionais (capacidade anti-hipertensiva, atividade antibacteriana e antibiofilme). Todos foram não genotóxicos, mas a citotoxicidade foi dependente da concentração do extrato, com aplicação totalmente segura até 1 mg/mL. Nos extratos antioxidantes obtidos por aquecimento óhmico o ácido 4-hidroxibenzóico foi o composto que apresentou maior concentração (125.86 μg/ g drêche) e o extrato de etanol 60%:água (v/v) foi o que apresentou maior atividade antioxidante. No entanto, ambos os extratos demonstraram não ter atividade mutagénica, e ambos foram capazes de inibir 50% da enzima conversora de angiotensina-I (ECA), sendo o extrato com melhor resultado o 80% etanol:água (v/v). Os extratos de drêche apresentaram efeito inibitório contra Bacillus cereus e em menor grau contra Listeria monocytogenes, a 5,00 e 2,50 mg/mL, para 80% etanol:água (v/v) e 60% etanol:água (v/v) respetivamente, e também, as mesmas concentrações inibiram a formação de biofilme. A análise do impacto do trato gastrointestinal (TGI) mostrou que o método sólido-líquido (60% etanol:água (v/v)) gerou extratos com maior atividade antioxidante e maior teor de fenólicos totais. No entanto, os compostos presentes no extrato obtidos por aquecimento óhmico com 80% etanol:água (v/v) apresentaram maiores índices de bioacessibilidade dos polifenóis. Todos os extratos aumentaram o crescimento dos microrganismos probióticos testados. As farinhas resultantes da extração foram estudadas ao longo do TGI, mostrando que após uma diminuição inicial, existe um aumento na atividade antioxidante e fenólicos totais até final do TGI. Além disso, também modularam positivamente o crescimento de bactérias probióticas bem como do seu metabolismo, com a produção de ácidos gordo de cadeia curta.The main objective of this thesis was to explore the value of the by-product of beer production, BSG, to promote the principle of sustainable development by obtaining value-added ingredients. So, from this residue, extractions were carried out using solid-liquid and ohmic heating extractions and solvents used in the food industry (ethanol and water) (to guarantee the maintenance of compositional integrity, functionality and safety of the bioactive extracts obtained). All hydroethanolic extracts showed high antioxidant capacity, and the highest values were obtained for the extract 60% ethanol:water (v/v). Identification by HPLC showed that catechin and vanillin were the main compounds identified with the highest concentration (223.6 e 109.2 μg/g BSG respectively) obtained by extraction using 60% ethanol:water (v/v). In the biological activity assays, the extracts proved to be multifunctional (antihypertensive capacity, antibacterial and antibiofilm activity). All were non-genotoxic, but cytotoxicity was dependent on extract concentration, with totally safe application for all extracts up to 1 mg/mL. In the antioxidant extracts obtained by ohmic heating 4-hydroxybenzoic acid was the compound that showed the highest concentration (125.86 μg/ g drêche) and the 60% ethanol extract:water (v/v) was the one that showed the highest antioxidant activity. However, both extracts showed no mutagenic activity, and both were able to inhibit 50% of the angiotensin-I converting enzyme (ACE), with the extract with the best result being 80% ethanol:water (v/v). The BSG extracts showed an inhibitory effect against Bacillus cereus and to a lesser extent against Listeria monocytogenes, at 5.00 and 2.50 mg/mL, for 80% ethanol:water (v/v) and 60% ethanol:water (v/v). v) respectively, and also, the same concentrations inhibited biofilm formation. The gastrointestinal tract (GID) analysis showed that the solid-liquid method containing 60% ethanol:water (v/v) was the extraction with the highest antioxidant activity and the highest content of total phenolics. However, the compounds present in the extract obtained by ohmic heating with 80% ethanol:water (v/v) showed higher values of bioaccessibility indexes for polyphenols. All extracts increased the growth of the probiotic microorganisms tested The flours resulting from solid-liquid extraction and ohmic heating were studied along the GID showing that after an initial decrease there was an increase in antioxidant activity and total phenolic compounds along the GID These flours also positively modulated the growth of probiotic bacteria as well as their metabolism with the production of short chain fatty acids.This work was financially supported by Co-promoção, POCI-01-0145 -FEDER-006684, NORTE- 08-5369-FSE-000036. We would also like to thank the scientific collaboration of CBQF under the FCT – Fundação para a Ciência e a Tecnologia through project Multibiorefinery – _ Multi-purpose strategies for the valorization of a wide range of agroforestry by-products and fisheries: A step forward in the creation of an integrated biorefinery, (POCI-01-0145 -FEDER-0068) and the project UID/Multi/50016/2020, IID/BIO/04469/2020 and the PhD grant UMINHO/BD/11/2016 to Teresa Bonifácio-Lopes

Como melhorar a comunicação oral entre agentes artificiais e interlocutores humanos

Tese de mestrado, Ciência Cognitiva, 2021, Faculdade de Ciências, Universidade de LisboaCada vez estamos mais rodeados por agentes artificiais, desde chatbots a assistentes virtuais, com os quais interagimos. Este trabalho estuda a questão “Como melhorar a comunicação oral entre agentes artificiais e interlocutores humanos”, tendo como objetivo avaliar as emoções experienciadas por um humano na interação oral com um agente artificial, para permitir treinar estes agentes no reconhecimento do estado emocional do interlocutor e na geração de uma resposta empática, promovendo uma interação mais eficaz. A metodologia consistiu na avaliação de um estímulo vocal gerado por um agente, na caracterização vocal das emoções percecionadas e no estudo de modelos de reconhecimento de emoções e de treino de agentes artificiais, numa abordagem multidisciplinar envolvendo as áreas da Psicologia Cognitiva e da Inteligência Artificial. A avaliação das emoções percecionadas na comunicação oral suportou-se numa análise teórica e num inquérito on-line. Os resultados permitiram concluir que é possível a um humano reconhecer que está a interagir oralmente com um agente artificial, mas que nesta interação são percecionadas emoções negativas mais frequentemente do que na interação com humanos. A avaliação da codificação vocal das principais emoções percecionadas suportou-se em investigações sobre bases de dados de vozes e permitiu concluir que a língua não parece inviabilizar o reconhecimento das emoções e que a EU-Emotion Voice Database se mostrou adequada para este estudo. A análise de modelos de reconhecimento de emoções e de treino de agentes permitiu concluir que a implementação de um módulo de extração de características acústicas com base em coeficientes cepstrum de frequência de mel e de um módulo de categorização de emoções baseado em máquinas de vetores de suporte parecem adequar-se ao fim em causa. Sendo relevante implementar sistemas que permitam treinar agentes artificiais na deteção das emoções expressas por interlocutores humanos e a reagir empaticamente, conclui-se que tal parece viável, embora complexo.We are increasingly surrounded by artificial agents, from chatbots to virtual assistants, with which we interact. This work studies the question "How to improve oral communication between artificial agents and human interlocutors", aiming to evaluate the emotions experienced by a human in an oral interaction with an artificial agent, to enable the training of these agents in recognizing the emotional state of the interlocutor and in generating an empathic response, promoting a more effective interaction. The methodology consisted in the evaluation of a vocal stimulus generated by an agent, the vocal characterization of perceived emotions and the study of emotion recognition and artificial agents training models, in a multidisciplinary approach involving the areas of Cognitive Psychology and Artificial Intelligence. The evaluation of the emotions perceived in the oral communication was supported by a theoretical analysis and an online survey. The results show that it is possible for a human to recognize that is orally interacting with an artificial agent, but that in this interaction negative emotions are perceived more frequently than in the interaction with humans. The evaluation of the vocal coding of the main emotions perceived was supported in investigations on voice databases and led to the conclusion that language does not seem to prevent the recognition of emotions and that the EU-Emotion Voice Database was adequate for this study. The analysis of emotion recognition and artificial agents training models allowed the conclusion that the implementation of a module for the extraction of acoustic features based on Mel Frequency Cepstral Coefficients and a module for the categorization of emotions based on Support Vector Machines seem to be suitable for our purpose. Being relevant to implement systems that allow artificial agents training in detecting emotions expressed by humans and to react empathically, we conclude that this seems feasible, although complex

Phenolic Compounds from By-Products for Functional Textiles

Textile dyeing is known to have major environmental concerns, especially with the high use of toxic chemicals. The use of alternatives such as natural dyes rich in phenolic compounds has become extremely appealing in order to move towards a more sustainable circular economy. Phenolic dyes have the potential to functionalize textile fabrics with properties such as antimicrobial, antioxidant, and UV protection. Wastes/residues from the agri-food industries stand out as highly attractive sources of these compounds, with several by-products showing promising results in textile dyeing through the implementation of more sustainable and eco-friendly processes. This review presents an up-to-date exploration of the sources of phenolic compounds used in the textile industry over the past two decades, with a primary focus on the functional properties they provide to different fabrics. The research highlights a surge in interest in this theme since 2017, accentuating a noticeable upward trend. Throughout this review, emphasis is given to by-products from the agri-food industry as the sources of these compounds. The reviewed papers lay the foundation for future research, paving the way for exploring the potential of raw materials and by-products in the creation of functional and smart textiles

Impact of gastrointestinal digestion simulation on brewer’s spent grain green extracts and their prebiotic activity

"Available online 25 January 2023"Brewers spent grain (BSG) is a by-product of the beer industry and a potential source of bioactive compounds. In this study two methods of extracting bioactive compounds from brewers spent grain were used solid-to-liquid conventional extraction (SLE) and solid-to-liquid ohmic heating extraction (OHE) coupled with two ratio combinations of solvents: 60% and 80% ethanol:water (v/v). The bioactive potential of the BSG extracts was assessed during the gastrointestinal tract digestion (GID) and the differences in their antioxidant activity, total phenolic content and characterization of the polyphenol profile was measured. The SLE extraction using 60% ethanol:water (v/v) was the extraction method with higher antioxidant activity (33.88 mg ascorbic acid/g BSG initial; 16.61 mg ascorbic acid/g BSG - mouth; 15.58 mg ascorbic acid/g BSG stomach; 17.26 mg ascorbic acid/g BSG duodenum) and higher content in total phenolics (13.26 mg gallic acid/g BSG initial; 4.80 mg gallic acid/g BSG mouth; 4.88 mg gallic acid/g BSG stomach; 5.00 mg gallic acid/g BSG duodenum). However, the OHE extraction using 80% ethanol:water (v/v), had a higher bioaccessibility index (99.77% for ferulic acid, 72.68% for 4-hydroxybenzoic acid, 65.37% for vanillin, 28.99% for p-coumaric, 22.54% for catechin) values of polyphenols. All the extracts enhanced (except for SLE for 60% ethanol:water (v/v) at 2 and 1.5%, and for 80% ethanol:water (v/v) at 2% with Bifidobacterium animalis spp. lactis BB12, where no growth was observed) the growth of the probiotic microorganisms tested (Bifidobacterium animalis B0 O.D.s between 0.8240 and 1.7727; Bifidobacterium animalis spp. lactis BB12 O.D.s between 0.7219 and 0.8798; Lacticaseibacillus casei 01 O.D.s between 0.9121 and 1.0249; and Lactobacillus acidophilus LA-5 O.D.s between 0.8595 and 0.9677), demonstrating a potential prebiotic activity of BSG extracts.The authors would like to thank the projects Co-promoção, POCI-01- 0145-FEDER-006684, NORTE-08-5369-FSE-000036. and the project Multibiorefinery (POCI-01-0145-FEDER-00668). Furthermore, the authors would also acknowledge the FCT projects UID/BIO/04469/2020 and UID/Multi/50016/2020. The author Teresa Bonifácio-Lopes would also like to acknowledge the Ph.D. grant UMINHO/BD/11/2016.info:eu-repo/semantics/publishedVersio

Impact of circular brewer's spent grain flour after in vitro gastrointestinal digestion on human gut microbiota

Brewer's spent grain (BSG) solid residues are constituted by dietary fibre, protein, sugars, and polyphenols, which can have potential effects on human health. In this study, for the first time, the flours obtained from solid residues of solid-liquid extraction (SLE) and ohmic heating extraction (OHE) were applied throughout the gastrointestinal digestion simulation (GID), in order to evaluate their prebiotic potential and in vitro human gut microbiota fermentation. The results showed that the digestion of BSG flours obtained by the different methods lead to an increase throughout the GID of total phenolic compounds (SLE: from 2.27 to 7.20 mg gallic acid/g BSG-60% ethanol:water (v/v); OHE: 2.23 to 8.36 mg gallic acid/g BSG-80% ethanol:water (v/v)) and consequently an increase in antioxidant activity (ABTS-SLE: from 6.26 to 13.07 mg ascorbic acid/g BSG-80% ethanol:water (v/v); OHE: 4.60 to 10.60 mg ascorbic acid/g BSG-80% ethanol:water (v/v)-ORAC-SLE: 3.31 to 14.94 mg Trolox/g BSG-80% ethanol:water (v/v); OHE: from 2.13 to 17.37 mg Trolox/g BSG-60% ethanol:water (v/v)). The main phenolic compounds identified included representative molecules such as vanillic and ferulic acids, vanillin and catechin, among others being identified and quantified in all GID phases. These samples also induced the growth of probiotic bacteria and promoted the positive modulation of beneficial strains (such as Bifidobacterium spp. and Lactobacillus spp.) present in human faeces. Moreover, the fermentation by human faeces microbiota also allowed the production of short chain fatty acids (acetic, propionic, and butyric). Furthermore, previous identified polyphenols were also identified during fecal fermentation. This study demonstrates that BSG flours obtained from the solid residues of SLE and OHE extractions promoted a positive modulation of gut microbiota and related metabolism and antioxidant environment associated to the released phenolic compounds.info:eu-repo/semantics/publishedVersio

Erratum: Bioactive extracts from brewer's spent grain (Food and Function (2020) 11 (8963–8977) DOI: 10.1039/D0FO01426E)

The authors regret that an incorrect version of Table 2 was included in the original article. The correct version of Table 2 is presented below. (Figure Presented).“Consequently, sections of the text in the manuscript should be adjusted according to this change, and these are detailed below. The paragraph on page 8968 beginning “As it can be seen in Table 2…” should be correctly given as follows: “As it can be seen in Table 2, the content of total phenolics (TPC) varied from 1.83 mg gallic acid per g BSG, when ethanol was used, to 13.26 mg gallic acid per g BSG for the 60% ethanol : water extract, which represents a 0.9 fold increase in the extraction yield. It is worth highlighting that the highest amount of TPC obtained in the present work (13.26 mg gallic acid per g BSG) was higher than the values previously reported by McCarthy et al.41 (1.26–4.53 mg gallic acid per g BSG) by alkaline hydrolysis. It is also possible to see that the extraction with 60% ethanol : water was more efficient than the one performed with 100% ethanol. According to Spigno et al.42 the addition of water to organic solvents leads to the increase of the polarity of medium, which facilitates phenolic compound extraction. The results obtained in the present work (Table 2) also showed that the extraction using only water was not as efficient as when using ethanolic mixtures as solvents, since phenolic compounds have higher affinity for less polar medium, such as ethanol.43” The sentence beginning “ This value is much lower compared...” should be correctly given as “This value is much lower compared to that for the 60% ethanolic extract, since it showed ca.7 times less activity in the case of the ABTS method and ca. 10 times less than in the case of the ORAC method.” The sentence beginning “The highest values of ABTS…” should be correctly given as “The highest values of ABTS assay were obtained with 60% ethanolic extract, which was 5 times higher than the water extract and very close to the 80% ethanolic extract.”” The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.info:eu-repo/semantics/publishedVersio