Mountain Research Center

Funder

Organizational Unit

Publications

Exploring the role of Autochthonous lactic acid Bacteria in enhancing quality and safety of Alheira

Publication . Fernandes, Nathália; Cadavez, Vasco; Gonzales-Barron, Ursula

The alheira is a traditional meat sausage produced in the Portuguese region of Trás-os-Montes. Lactic Acid Bacteria (LAB) are the dominant microorganisms in alheira and can endow it with various technological properties. This study aimed: 1) Isolate and identify LAB from artisanally produced alheiras from the Trás-os-Montes region; 2) Study their phenotypic characteristics and in vitro antimicrobial activity; and 3) Differentiate and associate the phenotypic characteristics of the LAB with 16S ribosomal gene sequencing data. Sixty-two LAB isolates were identified and Enterococcus (E.) faecium corresponded to 32.3% of isolates, followed by Leuconostoc (L.) mesenteroides (19.4%) and Latilactobacillus (Lb.) sakei (17.7%), aligning with previous research on traditional Portuguese fermented meat sausages. The phenotypic analysis of LAB isolates indicated diverse acidification capacities, proteolytic activities, and inhibitory effects against foodborne pathogens Listeria (L.) monocytogenes, Salmonella (S.) Typhimurium and Staphylococcus (S.) aureus. LAB play an essential role as biological control agents, generating metabolites with antimicrobial properties, including organic acids, proteases, peptidases and bacteriocins. Overall, lactobacilli displayed high inhibition activity ((inhibition zone radius higher than 10 mm) against the pathogens S. aureus, L. monocytogenes and S. Typhimurium. The mechanisms of pathogenic microorganism inhibition remain to be clarified and will be the subject of future studies. However, these results reveal the significant diversity of LAB found in artisanally produced alheiras, as well as their contribution to the microbiological safety and organoleptic characteristics of alheiras.

2024Master thesis

Open access

Susceptibility of Foodborne Pathogens to Milk-Origin Lactic Acid Bacteria Supernatants: A Comprehensive Meta-Regression Study

Publication . Fernandes, Nathália; Loforte, Yara; Cadavez, Vasco; Gonzales-Barron, Ursula

This systematic review and meta-analysis compile the in vitro antimicrobial efficacy of lactic acid bacteria (LAB) supernatants against three common pathogenic bacteria found in dairy products: Salmonella spp., L. monocytogenes, and Staphylococcus aureus. After screening and analysis of full papers, identified by searches in PubMed, Scopus, and Web of Science databases, thirty-nine studies were regarded as relevant, and a total of 510 observations were recorded. The effects of moderators on inhibition diameters were assessed by adjusting three pathogen-specific meta-regression models. Results showed that, in general terms, strains from the Enterococcus genus displayed the highest inhibition values against L. monocytogenes (15.90 ± 2.138 mm), whereas Lacticaseibacillus strains were more effective against S. aureus (11.89 ± 0.573 mm). The well diffusion test outperformed the spot and disk diffusion tests, and more acidic LAB supernatants resulted in higher measurements of inhibition diameters (p < 0.001). Meta-regression models incorporating LAB genus, pathogen concentration, and incubation time explained 33.8%, 52.3%, and 19.8% of the total variance in inhibition diameters for L. monocytogenes, Salmonella spp., and S. aureus, respectively. None of the three models showed evidence of publication bias. This meta-regression study demonstrated that LAB strains present in dairy products possess a variable capacity to inhibit any of the three foodborne pathogens. Overall, L. monocytogenes was found to exhibit greater susceptibility than Salmonella spp. and S. aureus; thus, the antilisterial capacity of the selected LAB strains could be exploited in developing biocontrol strategies for cheese-making.

2024Journal article

Open access

Foliar application of biostimulants improves nutritional and bioactive quality of walnuts

Publication . Pascoalino, Liege; Pires, Tânia C.S.P.; Pinela, José; Rodrigues, M.A.; Ferreira, Isabel C.F.R.; Barros, Lillian; Barreira, João C.M.; Reis, Filipa S.

Owing to their health benefits, walnuts are attracting interest as a good option for nutritious meals, thereby promoting their production. Furthermore, the adoption of ecologically and environmentally friendly agriculture strengthens biostimulant use as a sustainable complement to traditional fertilizers. This study evaluated the effects of different foliarapplied biostimulants in walnut tree orchards, in northeastern Portugal, on walnuts' chemical composition and bioactivity. RESULTS: Walnut samples were rich in fat (particularly the polyunsaturated linoleic acid), dietary fiber and protein. Sucrose was the most prevalent soluble sugar, followed by glucose and fructose. Studied samples also showed an antioxidant activity comparable (or superior) to that of Trolox. Some plant biostimulants (e.g. Sprint Plus®) had a positive impact on the nutritional composition of walnuts, more specifically by boosting tocopherol levels, besides improving the bioactivity of walnut extracts against specific bacteria. CONCLUSION: Overall, this research demonstrated that important quality traits of walnuts can be improved using sustainable agricultural bioproducts and practices.

2024Journal article

Open access

Developing a sustainable and functionalized pumpkin fruit pulp formulation using biobased preservatives: The PulpIng Project

Publication . Leichtweis, Maria Gabriela; Molina, Adriana K.; Pires, Tânia C.S.P.; Pereira, Carla; Oliveira, Beatriz; Ferreira, Isabel C.F.R.; Barros, Lillian

The PulpIng project is committed to advancing the circular economy and promoting sustainable agro-industrial practices. To achieve this goal, the project aims to develop new pumpkin fruit pulp formulations functionalized with natural preservative extracts from pumpkin by-products. The seeds, peels, and fibers from different pumpkin genotypes cultivated in five different countries were used to obtain extracts with preservative properties. These extracts showed great antioxidant and antimicrobial capacity, as well as a diversified phenolic compounds profile. The peels proved to be the most promising by-product, being thus selected to optimize the extraction by RSM, to reach the most efficient conditions leading to preservative compounds-rich extracts. In the next step, the extracts will be incorporated into the new pulp formulations, which quality will be assessed during shelf-life. Waste and wastewater management will also be addressed. By pursuing these goals, the PulpIng project ambitions innovation and sustainability within the agro-industrial sector.

2023Conference object

Open access

Unveiling Key Parameters: Time Windows and Travel Times in Capacitated Waste Collection

Publication . Silva, Adriano S.; Lima, José; Silva, Adrián; Gomes, Helder; Pereira, Ana I.

Numerous studies in waste management propose solutions to the Waste Collection Problem, often focusing on constraints such as time windows and truck capacity. Travel times between points play a vital role in optimizing waste collection. However, the methods for determin- AQ1 ing them are frequently omitted. Another parameter that has a great influence on waste collection is the time window. Here, the impact of time windows and travel times on the capacitated waste collection problem with time windows solution was assessed for collecting three waste types. Surprisingly, travel times were found to have minimal influence on route optimization, while time windows significantly affected the algorithm’s ability to identify the most efficient collection route. Addressing AQ2 these considerations is crucial for practical application and improving the performance of waste collection algorithms in real-world contexts.

2024Conference object

Restricted access