Escola Superior de Biotecnologia
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Browsing Escola Superior de Biotecnologia by Sustainable Development Goals (SDG) "09:Indústria, Inovação e Infraestruturas"
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- Bioactive potential of olive leaf by-product throughout in vitro gastrointestinal digestionPublication . Sánchez-Gutiérrez, Mónica; Gómez-García, Ricardo; Carrasco, Elena; Rodríguez, Alejandro; Pintado, ManuelaOlive leaf, an abundant and underutilized byproduct of the olive industry, has gained attention as a potential functional ingredient due to its high content of dietary fiber and phenolic compounds. However, little is known about its bioaccessibility and transformation throughout the digestive process, limiting its application in food formulations. This study provides a comprehensive and quantitative assessment of how ground olive leaf bioactive compounds behave during gastrointestinal digestion, offering new insights into their stability and potential health benefits. The total phenolics content and antioxidant activity of ground olive leaf increased in the oral and gastric phases, decreasing slightly in the intestinal phase, with a bioaccessibility of 46% and up to 70% for the total phenolic content and antioxidant activity, respectively. The principal individual phenolic compounds identified in the intestinal phase were oleuropein, luteolin-7-glycoside, luteolin-6-glycoside and ferulic acid, with bioaccessibilities of up to 97%. The main soluble sugars (fructose, glucose, and sucrose) and organic acids (succinic, citric, and acetic acids) detected in the olive leaf samples showed different behaviors during gastrointestinal digestion: sugars increased in the oral and gastric phases but decreased in the intestinal phase, with high bioaccessibility despite reduced recovery, while organic acids remained mostly stable, except for citric acid, which decreased significantly in the intestinal phase, all showing close to 100% bioaccessibility. These results provide the first detailed evidence of the digestive fate of ground olive leaf bioactive compounds, reinforcing its potential as a functional ingredient. Its natural availability, without requiring pre-treatment, combined with its high antioxidant potential and bioaccessibility, highlights its relevance for the development of innovative food ingredients, aligning with circular economy principles and sustainable food strategies.
- Breaking the virus: yeast glucans as an effective alternative to acyclovir in HSVI treatmentPublication . Tavares-Valente, Diana; Moreira, Helena; Sousa, Pedro; Amorim, Manuela; Conde, António; Pintado, Manuela; Fernandes, João; Azevedo-Silva, JoãoGlucans, structural polysaccharides in the yeast cell wall, are known for their biological and immunomodulatory capacities, helping in prevention and management of infections. Herpes simplex virus type 1 (HSVI) is a prevalent infection that causes great comorbidity and is challenging to treat due to the adverse effects of standard antiviral drugs like acyclovir. This study assessed the potential of yeast glucans extracted from two different origins − a steviol-glycoside producing strain and a wild-type strain- to circumvent HSVI infection, either in vitro and ex vivo. Treatment with glucans in keratinocytes and macrophages in vitro reduced cell infection similarly to acyclovir. However, unlike acyclovir, glucans demonstrated an immunostimulatory effect, increasing the production of IL-1β, TNF-α and IL-6. Additionally, both glucans were formulated with squalane for skin application. This formulation improved glucans penetration in the skin, restored skin structure and reduced the cytopathic effect of HSVI infection. In summary, this study highlights yeast glucans as a natural therapeutic alternative for HSVI treatment, offering an option with an excellent safety profile. Moreover, using glucans from industrial side-streams promotes a sustainable approach, contributing to the circular economy.
- Carnosic acid production from sugarcane syrup by engineered yeast in fed-batch fermentationPublication . Carsanba, Erdem; Fernandes, Sara; Beato, Felipe; Carvalho, Luís Carlos; Pintado, Ana; Lopes, Ana; Ribeiro, Mónica; Leal, Tânia; Pintado, Manuela; Oliveira, CarlaPhenolic diterpene carnosic acid (CA) is widely used in the food, nutritional health, and cosmetic industries due to its antioxidative and antimicrobial properties. This work aimed to overproduce CA in Saccharomyces cerevisiae from sugarcane syrup in fed-batch 2 L bioreactor fermentation. A geranylgeranyl diphosphate (GGPP)-producing strain modified with genes encoding the enzymes copalyl diphosphate synthase (Pv.CPS), miltiradiene synthase (Ro.KSL2), hydroxy ferruginol synthase (Ro.HFS), CA synthase (Ro.CYP76AK8), CYP reductase (At.ATR1), and transketolase (TKL1) was used. Lowering the feed rate from 12–26 g/L/h to 7–8 g/L/h, and the use of a dynamic dissolved oxygen (DO) trigger (min. 10%, max. 40%, threshold 70%) instead of a DO trigger of 30%, enhanced CA production by 27%. As a result, the highest CA titer ever reported to date, 191.4 mg/L, was obtained in 4-day fermentation. This study shows the feasibility of engineered yeast to produce CA from the sustainable feedstock sugarcane syrup.
- Design of paper-based analytical devices for chemical and biochemical assays of biomarkers in biological fluids of non-invasive collectionPublication . Ferreira, Francisca Teixeira Soares da Mota; Mesquita, Raquel Beatriz Ribeiro de; Rangel, Antonio Osmaro Santos SilvaEnsuring basic healthcare access around the world remains a challenge, particularly in lowincome regions. In response, international initiatives such as the Sustainable Development Goals (SDGs) and the World Health Organization (WHO) guidelines emphasize the need to develop innovative, accessible, and cost-effective diagnostic tools. Point-of-care testing has emerged as an ideal solution, enabling rapid and decentralized analysis. Among these type of devices, microfluidic paper-based analytical devices (µPADs) have gained attention due to their affordability, portability, and ease of use, making them a particularly valuable tool in resource-limited locations. The purpose of the work presented throughout this thesis was to design and develop innovative point-of-care methodologies based on the µPAD approach for the determination of several healthrelated parameters, that could serve as an adding tool in the diagnosis and monitoring of several health conditions. The use of biological samples of non-invasive collection, such as saliva and urine, enhances diagnostic accessibility, particularly in point-of-care settings where traditional sample collection may be impractical or even impossible. Additionally, this thesis also explores the use of colorimetric detection methods, a straightforward approach to quantifying the targeted analytes by producing visible colour changes. To further improve the specificity and accuracy of these diagnostic tools, enzymatic reactions were incorporated into some of the developed µPADs. The first developed device was dedicated to the quantification of total iron in urine samples by using the colorimetric reaction of bathophenanthroline with iron (II) coupled with hydroxylamine, a well-known reducing agent capable of converting iron (III) in iron (II). To handle the potential colour of the urine samples, a sample blank was included in the device. This feature was vital to ensure the applicability of the developed μPAD, as urine may present a wide variability of colour range, from light yellow to brownish. The determination of nitrate was also accomplished in urine samples with a newly developed µPAD. This device included the enzymatic reaction of nitrate reductase to perform the conversion of nitrate to nitrite and the Griess reagent which provided the colorimetric detection of the resulting nitrite. In order to delay the vertical flow and increase the extent of the enzymatic reaction, a hydrophilic membrane layer was also incorporated into the device. The small porosity of this membrane also led to the retention of the compound responsible for the colour of urine, enabling a direct analysis of the samples. The next devices developed performed the quantification of NHX and urea in saliva samples but with a more complex approach. Not only were the devices composed of four layers, but the detection relies on the diffusion of NH3 (g) through a gas-diffusion membrane to produce a colorimetric change of a pH indicator. The hydrophobicity of this membrane also helped eliminate possible interferences of the saliva sample in the colorimetric reaction, since it did not allow the sample to pass through the membrane and reach the colour reagent. The urea determination was accomplished by including urease in the device, since it selectively catalyzes the dissociation of urea in ammonia and carbon dioxide. The urease activity determination was accomplished using a similar structure and reactions to the one used for the urea µPAD. However, the determination itself was achieved using the kinetic capabilities of the enzyme by correlating to the urease activity with the variation of the signal obtained between two different enzymatic reaction times. This strategy not only allowed a more accurate quantification but also suppressed the influence of NHX already present in the samples. The last device developed using the µPAD structure approach was to quantify glucose in saliva samples. With only two layers in its composition, this device uses a combination of two enzymatic reactions. First, glucose oxidase converts glucose into gluconic acid and hydrogen peroxide, then followed by the release of oxygen from hydrogen peroxide performed by peroxidase. The colorimetric detection is accomplished with the oxidation of o-dianisidine. In this work, a correlation between the concentration of glucose in saliva and blood was also successfully established, using #5 saliva samples of diabetic patients and the correspondent glucometer measurements provided by the patients. A rather different approach was used to perform the semi-quantitative analysis of E. coli DNA. Instead of developing a µPAD, an option was made to design a barcode-style lateral flow strip that would allow the semi-quantitative detection of E. coli. The amplification of the DNA in the sample was performed using the Loop-Mediated Isothermal Amplification (LAMP) technique since it can be performed at a constant temperature and provides high sensitivity and specificity results. The developed methodology, although requiring further optimization, showed reliable performance and offers a rapid, cost-effective method for E. coli detection. Overall, this thesis demonstrates the potential of microfluidic paper-based analytical devices and lateral flow assays as innovative, cost-effective diagnostic tools for point-of-care applications. By addressing critical challenges such as sample complexity, reagent stability, and measurement accuracy, the developed devices enhance accessibility to reliable testing, particularly in resourcelimited settings. Their affordability and ease of use further emphasize their role in expanding diagnostic capabilities outside traditional laboratory environment.
- Exploring new sustainable solutions based on chitosan and cellulose crystals towards the preventive conservation of cultural heritagePublication . Silva, Nádia Suati Caetano da; Costa, Patrícia Raquel Fernandes de Melo Moreira da; Pintado, Maria Manuela Estevez; Madureira, Ana Raquel Mendes Ferreira MonteiroOutdoor sculptures made of stone and mortar are a significant part of the worldʼs cultural heritage. Consequently, their conservation is of great importance, mainly due to their vulnerability to deterioration. Deterioration occurs as a combination of factors that cause alterations and devalue the artworks over time, including those resulting from biodeterioration mechanisms triggered by the growth and activity of microorganisms. Developing sustainable strategies to slow down the proliferation of microorganisms is necessary to reduce the negative environmental and human health impacts of currently used toxic biocides. Hence, this thesis aims to contribute to developing low-toxicity and more sustainable antimicrobial coatings for the preventive conservation of stone heritage, particularly outdoor sculptures. Firstly, an evaluation of the biocontamination and microbiological composition of five outdoor sculptures, made of different materials and located in the district of Porto (Portugal), was performed. Two methodologies were tested to collect samples from the sculptures in a non-invasive and non-destructive way: cotton swabs (classical approach) and poly(2-hydroxyethyl methacrylate) cryogels (alternative method). The quantification and determination of the cell viability of the microorganisms collected were performed by flow cytometry, which proved to be an analytical technique of interest for microbiological studies of cultural heritage. Both methods were effective, although higher concentrations of microorganisms were collected with swabs, while data visualisation of viable and non-viable cells was clearer with cryogels. Consequently, swab samples were taken to characterise the epilithic bacterial and fungal communities of the sculptures. High-throughput sequencing revealed great taxonomic diversity and species richness, including in well-preserved sculptures. Fungal diversity was lower than that of the bacterial communities. Proteobacteria was the core taxa common to all the sculptures. Ascomycota were also detected in all the sculptures and Basidiomycota were a significant part of the microbiomes in granite, where an abundance of pigment-producing microorganisms was also found. Additionally, colourimetry and adenosine triphosphate quantification assays quickly identified contaminated areas of the sculptures. The next stage of the work dealt with the preparation and characterisation of chitosan formulations, to be used as antimicrobial coatings to inhibit the growth of microorganisms in sculptures. The first set of formulations consisted of chitosan solutions containing citric acid and different concentrations of sodium tripolyphosphate (CHGCA-TPP), which were polymerised into films for their characterisation. Fourier transform infrared (FTIR) spectroscopy confirmed the establishment of cross-linking interactions, and the films exhibited partial wettability (40.81-31.44°), solubility (43.64-55.14%) and swelling (123.36-75.17%) in water, but allowed water vapour exchanges due to their high permeability (140.055-372.575 g m-2 d). The films reduced the growth of microorganisms that commonly colonise stone heritage: Staphylococcus aureus (0.87-1.58-log reduction), Bacillus cereus (ca. 1-3-log reduction), Rhodotorula spp. (between 0.73-1.27-log reduction and complete inhibition) and Penicillium chrysogenum (11.92-21.48% inhibition). Another set of formulations was prepared to enhance the properties of the CHGCA-TPP formulations. A screening was conducted with chitosan solutions containing microcrystalline cellulose (MCC) or cellulose nanocrystals, and the chosen formulation was supplemented with oregano essential oil (OEO) at 1% and 2%. Cross-linking interactions and incorporation of OEO were confirmed by FTIR analysis of the films, which remained poorly soluble (15.74-16.85%), with low percentages of swelling (16.10-28.22%) and relatively low wettability (> 70°). These formulations are an improvement on the CHGCA-TPP ones, including their antimicrobial action, since the films containing 2% OEO completely inhibited the growth of S. aureus, Rhodotorula spp. and P. aeruginosa, induced ca. 60% inhibition of P. chrysogenum and reduced the growth of B. cereus. Lastly, the two most promising formulations (CHGCA-TPP-a and 2-MCC-OEO-2) were tested in granite, limestone and marble samples. Both formulations polymerised on the stones’ surfaces, as confirmed by scanning electron microscopy and FTIR spectroscopy, but formed irregular coatings. The CHGCA-TPP-a coating reduced the wettability of granite and limestone, while 2-MCC-OEO-2 did the same in a more pronounced way and in all stone types. Neither coating caused visible colour changes when the formulations were applied with a brush. In vitro antimicrobial assays with stone samples inoculated with selected strains showed that CHGCA-TPP-a inhibited the growth of B. cereus, Rhodotorula spp. and P. aeruginosa in granite after 7 days to ca. 4 to 5 log10 (CFU mL -1 ). In contrast, 2-MCC-OEO-2 reduced the concentrations of viable cells in all stone types to ca. 3 to 5 log10 (CFU mL -1 ) depending on the strain. In situ antimicrobial assays, where samples were placed in an outdoor setting, showed that CHGCA-TPP-a did not have an inhibitory effect under the conditions tested, with concentrations of viable cells equal to or higher than those of uncoated slabs, regardless of the mode of application of the formulation (deposition with a micropipette or spreading by brush) or the number of treatments over the assay period. However, multiple applications of 2-MCC-OEO-2 with a micropipette over time reduced the concentrations of viable cells in granite and marble, but the same occurred only in limestone when the coating was applied with a brush. In conclusion, this work added to the knowledge of the biocontamination and diversity of the microbiomes of outdoor sculptures, in particular of the Porto district in Portugal, which can help outline future conservation strategies. The chitosan formulations tested, especially those with MCC and OEO, are a potential base for further development and optimisation of novel low-toxicity antimicrobial coatings towards more sustainable preventive conservation strategies of stone heritage.
- Functional proteins and peptides obtained from fish by-productsPublication . Ghalamara, Soudabeh; Pintado, Maria Manuela Estevez; Silva, Sara Nunes da Costa e; Ferreira, Carla Maria Carvalho Gil Brazinha de BarrosMarine processing industries face significant challenges due to excessive by-products, which contribute to both environmental and economic issues. By-products from fish processing, which can constitute between 30% and 70% of the fish's total weight, exacerbate these challenges. Activities like washing, thawing, cooking, and fishmeal production generate more wastewater, intensifying the industry's environmental impact. This research explored using fish by-products like sardine cooking effluent and codfish bloodwater (CFBW) in a sustainable, zero-waste approach. The functional proteins and peptides extracted from fish by-products enhanced their value. The research evaluated their properties and potential food uses, aligning with circular bioeconomy principles. Fish by-products were fractionated using membrane technology at laboratory and pilot scales, aligning with zero-waste and biorefinery approaches. Ultrafiltration (UF) membranes were used to extract bioactive peptide-enriched fractions from sardine cooking effluent and CFBW at the laboratory scale. The process involved analyzing the selective permeation of small peptides (<1 kDa) using different membranes. The membranes effectively rejected (>10 kDa) of proteins and peptides but had relatively low rejection of <1 kDa peptides, with UP010 from CFBW achieving a 2% rejection rate and GH from sardine cooking effluent operating at minimum pressure (1 bar) achieving a 23% rejection rate. Peptides from CFBW using MW and UP010 membranes demonstrated potent antioxidant activity (high ABTS+ and ORAC values). However, the peptide fractions from sardine cooking effluent using the GH membrane did not enhance antioxidant activity. Nevertheless, the peptide fractions from CFBW (UP010 membrane) and sardine cooking effluent (GH membrane, 1 bar pressure) inhibited E. coli growth. Peptide-enriched fractions from CFBW were successfully obtained using a pilot-scale process involving microfiltration (MF), UF, and reverse osmosis (RO). The process aimed to fractionate CFBW into protein- and peptide-rich fractions. Chemical and biological characterization revealed that CFBW and pretreated CFBW consisted primarily of proteins and peptides. UF membrane fractions had lower protein content but higher ash levels. The UF retentate with a MWCO of 50 kDa, followed by RO, displayed the highest antioxidant values, indicating the presence of potent antioxidants. Additionally, the UF permeate obtained with a MWCO of 50 kDa from the MF-PFG showed antimicrobial activity against E. coli. A pilot-scale integrated membrane process was developed to obtain protein- and peptiderich fractions from sardine cooking effluent. The process used UF, nanofiltration (NF), and RO combined with enzymatic hydrolysis. Specifically, the RO retentate fractions of NF retentate were derived from diluted sardine cooking effluent, diluted hydrolyzed UF retentate, and diluted non-hydrolyzed UF retentate. The process involved UF, nanofiltration (NF), and RO combined with enzymatic hydrolysis. Specifically, the RO retentate fractions of NF retentate fractions were derived from water-diluted sardine cooking effluent (sardine cooking effluent-NF-RO), water-diluted UF retentate hydrolyzed (UF-H-NF-RO), and water-diluted UF retentate non-hydrolyzed (UF-NH-NF-RO). UF-H-NF-RO showed enhanced antioxidant and antimicrobial activities. The UF-NH-NF-RO peptide fraction displayed significantly enhanced functional properties in terms of WHC, FBC, emulsifying properties, and foaming properties at pH 4. In vitro digestion analysis showed this fraction also had the highest antioxidant activity, and none of the fractions exhibited cytotoxicity. Finally, foamy fish sauces (FFSs) were developed and evaluated using protein/peptide and lipofish fractions obtained from centrifugation of sardine cooking effluent. The control sample (CS) used a butter-based sauce emulsified with lecithin. An alternative lipofish sauce (LS) substituted unsalted butter with fish oil and included lecithin as the emulsifier. Three other formulas, namely lipofish-sardine cooking effluent-NF-RO-sauce (LSS), lipofish-UFH-NF-RO-sauce (LHS), and lipofish-UF-NH-NF-RO-sauce (LNHS), replaced unsalted butter with fish oil and incorporated a combination of protein/peptide fractions and lecithin. Despite minor physicochemical differences, the sauce formulas showed improvements compared to the control, including enhanced fatty acid (FA) content and profile, slightly reduced viscosity, improved foaming capacity, and enhanced foam stability. In vitro digestion analysis demonstrated high recovery of FAs, with the formula LNHS exhibiting the highest efficacy in scavenging ABTS radicals, indicating strong antioxidant properties. Furthermore, the FFS received remarkable acceptance from the trained panelists, who highly praised its texture, aroma, color, and flavor. This study's findings on fish by-products have significant implications for sustainable development in the fish processing industry. The research showcased the potential to obtain functional ingredients through eco-friendly strategies, preserving their bioactivity. These outcomes promote responsible and sustainable fish processing, reducing waste and maximizing by-product utilization.
- Innovative processing and sterilization techniques to unlock the potential of silk sericin for biomedical applicationsPublication . Veiga, Anabela; Ramírez-Jiménez, Rosa Ana; Santos-Rosales, Víctor; García-González, Carlos A.; Aguilar, Maria Rosa; Rojo, Luis; Oliveira, Ana L.Silk sericin (SS), a by-product of the textile industry, has gained significant attention for its biomedical potential due to its biocompatibility and regenerative potential. However, the literature lacks information on SS processing methods and the resulting physicochemical properties. This study represents the first step in protocol optimization and standardization. In the present work, different processing techniques were studied and compared on SS extracted from boiling water: evaporation, rotary evaporation, lyophilization, and dialysis, which presented a recovery yield of approximately 27–32%. The goal was to find the most promising process to concentrate extracted SS solutions, and to ensure that the SS structure was highly preserved. As a result, a new cryo-lyophilization methodology was proposed. The proposed method allows for the preservation of the amorphous structure, which offers significant advantages including complete dissolution in water and PBS, an increase in storage stability, and the possibility of scaling-up, making it highly suitable for industrial and biomedical applications. The second part of the work focused on addressing another challenge in SS processing: efficient and non-destructive sterilization. Supercritical CO2 (scCO2) has been gaining momentum in the last years for sterilizing sensitive biopolymers and biological materials due to its non-toxicity and mild processing conditions. Thus, scCO2 technology was validated as a mild technique for the terminal sterilization of SS. In this way, it was possible to engineer a sequential cryo-lyophilization/scCO2 sterilization process which was able to preserve the original properties of this natural silk protein. Overall, we have valorized SS into a sterile, off-theshelf, bioactive, and water-soluble material, with the potential to be used in the biomedical, pharmaceutical, or cosmetic industries.
- Tradition, science, and innovation : bioactive substances to mitigate microbiological risks of innovative alheirasPublication . Moreira, Inês Gonçalves de Azevedo; Teixeira, Paula Cristina Maia; Barbosa, Joana Inês Bastos; Albano, Helena da Conceição PereiraAlheira, a well-known delicacy produced in the north of Portugal, is a valuable part of our country's gastronomic heritage. Traditional alheiras, produced mainly with shredded pork and poultry meats, traditional wheat bread, olive oil, pork fat, and spices, are well-studied products and in the past years, some new formulations have emerged. Consumer preferences are constantly changing, so the food industry must proactively develop new products. In addition to traditional fermented sausages, mainly made with meat, other products are being developed to offer alternatives in line with consumer trends to reduce meat consumption. Vegetarian, vegan, and flexitarian diets are on the rise and sausages made from a variety of ingredients, such as codfish, mushrooms, tofu, soya, or vegetables, and other meat analogues are appearing worldwide. The aim of this study was to characterize these products, as little is known about their microbiological and chemical characteristics, and it becomes essential to determine their potential role in food safety. Classical microbiological and chemical analysis were therefore carried out on a universe of 21 alheiras, 14 of which were considered innovative and seven traditional. Enterobacteriaceae, Enterococcus, Lactic Acid Bacteria (LAB), yeasts, and moulds were the prevalent microbiota found in these innovative products. Sulphite-reducing Clostridium spores, Escherichia coli, Listeria monocytogenes, Salmonella spp. or Staphylococcus aureus were not detected in any innovative samples. No differences were observed between traditional and innovative alheiras concerning pH and water activity, while nitrites, nitrates and biogenic amines were within accepted limits for these products. Regarding organic acids, lactic acid was found in all samples analyzed, while malic and succinic acid seemed predominant only in the innovative alheiras. In addition, and to find some similarities between different types of alheiras and/or different producers, a study was carried out using next-generation sequencing technology to characterize the microbial communities associated with these products. The bacterial and fungal communities associated with each alheira were obtained by sequencing 16S rRNA gene V3- V4 and Internal Transcribed Spacer 2 (ITS2) regions of rRNA gene amplicons. Significant differences in the microbiota composition were found between samples, which were reflected by large differences in the profiles of the dominant species. More than 500 taxa were identified, particularly belonging to the families Lactobacillaceae and Xanthomonadaceae, which were found in all samples. In the analysis of the bacterial communities, genera belonging to lactic acid bacteria and Xanthomonas were predominant. Concerning fungi, the yeast Pichia was found in almost all the samples, followed by the filamentous fungus Alternaria. A challenge test was conducted in order to investigate the behaviour of foodborne pathogens (E. coli, L. monocytogenes, Salmonella Enteritidis and Staph. aureus) in traditional and innovative alheiras (codfish and vegetarian) along the product shelf-life at 4 ºC. Each target pathogen showed a different behaviour on the alheira matrices, but most pathogens were not detected in vegetarian alheira before the expiration date. As part of the risk mitigation, 491 LAB were isolated from traditional and innovative alheiras, and their antimicrobial activity against several foodborne pathogens was investigated. Six strains revealed antimicrobial activity by possible bacteriocin production against L. monocytogenes, Enterococcus faecalis, Clostridium sporogenes and Clostridium perfringens. These strains were identified as Lactiplantibacillus plantarum (2), Leuconostoc mesenteroides (1) and Pediococcus acidilactici (3). Additionally, orthologues of several class II bacteriocins genes were detected, namely Plantaricin E, Plantaricin F, Pediocin PA, Enterocin X, Leucocin A, and Coagulin A. None of these strains produced biogenic amines, gelatinase or DNase, as well as no hemolytic activity or lipase enzyme production was observed. However, only Lpb. plantarum 9A3 was sensitive to all the antibiotics tested and was therefore selected for further testing. Bacteriocins produced by Lpb. plantarum (9A3) demonstrated a bacteriostatic mode of action and stability across a wide range of conditions (temperature, pH, surfactants, detergents, and proteases). In conclusion, unlike traditional alheiras, which often contain pathogens, neither harmful organisms nor chemical hazards were found in these new products, even though they were produced by the same companies. Characterization of microbial communities by WGS revealed distinct microbial diversity patterns in traditional and innovative alheiras, even when produced in the same facilities and conditions. While this study offers initial insights into microbial diversity in these products, it sheds light on the behaviour of foodborne pathogens in the alheira matrix. Lactic acid bacteria increased throughout the shelf-life, particularly in traditional alheiras. Although each target pathogen showed a different behaviour on alheira matrices in general, vegetarian alheira proved to have particular characteristics that influence the viability of foodborne pathogens, since all pathogens tested were below the detection limit of the enumeration technique at the end of shelf-life in this matrix. Lactiplantibacillus plantarum 9A3 emerged as a promising candidate for industrial use due to the production of stable bacteriocins targeting pathogens like L. monocytogenes and C. perfringens and absence of virulence factors.
- Unlocking essential oils’ potential as sustainable food additives: current state and future perspectives for industrial applicationsPublication . Bautista-Hernández, Israel; Gómez-García, Ricardo; Martínez-Ávila, Guillermo Cristian Guadalupe; Medina-Herrera, Nancy; González-Hernández, María DoloresEssential oils (EOs) comprise a relevant bioactive fraction from diverse plant sources and vegetable tissues. Their beneficial properties have been mainly related to the presence of bioactive molecules such as monoterpenes and sesquiterpenes, among others, with beneficial properties against critical issues in the food industry that could promote sustainable production beyond organoleptic boosters. This review collects up-to-date information concerning EOs and their bioactive applications in the food field. In addition, a bibliometric analysis was applied to scientific and intellectual property databases to elucidate the current technological trends for EOs in the food sector. Thus, the current information on the evaluation of EOs in food systems has demonstrated that their application guarantees safe and high-quality foods, as they have the potential to partially replace some of the conventional synthetic antioxidants and antimicrobial agents according to sustainable trends.