Biblioteca Digital do IPB
Repositório de Publicações do Instituto Politécnico de Bragança
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Effect of drying process and incorporation of natural preservatives in the viability of lactic acid bacteria in yogurts
Publication . Ueda, Jonata Massao; Rodrigues, Paula; Barros, Lillian; Morales, Patricia; Carocho, Márcio; Heleno, Sandrina A.
Dairy products are considered one of the most consumed foods in the world, and yogurts are highly demanded for their flavour and nutritional properties, also including macronutrients, vitamins, minerals, or probiotics offered. To avoid food waste, alternatives to preserve food are highlighted, such as the addition of food preservatives or the production of powdered foods. Therefore, the objective of this work was to evaluate the survival of total lactic acid bacteria when natural extracts (rosemary, basil, and sage) were incorporated into yogurts, as well as to investigate their viability after the freezedrying process. Yogurts were prepared in the laboratory, and lyophilised plant extracts (30 mg/kg) were added. Total lactic acid bacteria were analysed for 14 days, in addition to evaluating the lactic acid and lactose contents by HPLC-DAD and HPLC-RI, respectively. Subsequently, the viability of Streptococcus thermophilus and Lactobacillus bulgaricus were evaluated in freeze-dried yogurts without the addition of vegetable extracts. Regarding the results obtained, there was a slight increase in the lactic acid bacteria counts, in addition to an increase in lactic acid and a reduction in the lactose content over 14 days, confirming the yogurt fermentation process. For the viability of S. thermophilus and L. bulgaricus during the lyophilisation process, a slight reduction of both bacteria was observed, but within the limits established by the Codex Standards (minimum of 107CFU/g). Therefore, the incorporation of plant extracts and the freeze-drying process did not significantly change the yogurts regarding the viability of the lactic acid bacteria, remaining a probiotic food.
Development of an integrated portal for farm audit management with geospatial support
Publication . Correia, Maria; Alves, Joaquim; Sequeira, Romeu; Exposto, José
This paper introduces the development of an innovative portal designed to optimize the management of agricultural field audits and ensure compliance with Common Agricultural Policy (CAP) regulations. The system is capable of handling more than five thousand audits, addressing specific audit requirements and integrating geospatial data management through technologies such as Django, and PostGIS, alongside libraries like Leaflet.js and Chart.js. The back end, developed in Django, provides a scalable and reliable infrastructure, supported by containerization deployment, while the front-end offers intuitive tools for data visualization and interaction. The platform’s modular design allows users at various access levels to efficiently manage data, track audit progress, upload documents, and monitor resources. By consolidating all audit tasks into a single application, the system reduces processing time, simplifies workflows, and improves data accuracy, leading to greater overall productivity. Preliminary testing demonstrates the system’s effectiveness for large-scale audits, and its scalability allows for future integrations, including IoT devices and predictive analytics, further enhancing decision-making and real-time data collection. This flexible and efficient solution meets the evolving needs of agricultural management.
In vitro evaluation of plant extracts as antifungal agents against Botrytis cinerea.
Publication . Marx, Ítala; Ardohain, Elizandra; Rodrigues, Paula; Barros, Lillian; Heleno, Sandrina A.
Grapevine bunch rot, caused by Botrytis cinerea, causes important economic losses every year in grape production [1]. However, indiscriminate use of pesticides to control this disease leads to serious problems such as consumer intoxication and the emergence of populations of pathogens resistant to fungicides. In this sense, the development of new natural ingredients against B. cinerea is of paramount relevance. Plant extracts are a valuable source of a wide variety of biologically active chemical defense constituents. Several plant bioactive compounds have been identified as possible antifungal agents, also associated with their antioxidant properties [2]. The objective of this work was to evaluate the effect of plant extracts rich in phenolic compounds (concentration of 10 mg/mL, each) on mycelial growth of B. cinerea in vitro. In this study, three formulations of plant extracts were evaluated (PreVine 1, PreVine 2 and PreVine 3). Potato Dextrose Broth (PDB) medium was prepared with agar and enriched with the three formulations of plant extracts. Negative control (CTR -) was treated only with water, and the positive control (CTR +) was treated with the conventional fungi cide Teldor® (active substance fenhexamid), concentration of 0.075 mg/mL. The obtained results demonstrated that all plant extracts formulations revealed the capacity to inhibit the growth of B. cinerea. The inhibitory potential was greater for PreVine 1, being responsible for inhibiting the growth of B. cinerea by 64% at 9 days of incubation, when compared to the control samples. As regards to the growth rate, plant extracts were able to reduce this parameter from 1.8391 (CTR -) to 1.2051 cm/day (PreVine 1). The positive antifungal activity of the plant extracts assessed, especially for the PreVine 1, could be attributed to their varied bioactive composition, such as several classes of phenolic compounds (i.e., flavonoids, phenolic acids, and tannins). In fact, these plant extracts have been described as source of compounds with biological activity against grape pathogens, by promoting a disruption of fungal cell membranes, inhibiting fungal enzymes and/ or inducing oxidative stress in fungal cells [3,4]. Considering the potential antifungal properties of these plant extracts formulations, these natural formulations could be candidates for application grape and wine industries as biofungicides, acting against grape pathogens, such asB. cinerea, decreasing, or avoiding the use of chemical fungicides.
Acorn pre-drying: implications for the food industry
Publication . Farrero, Bernardo; Ribeiro, Luís Frölén; Famiglietti, Antonio; Babo, Pedro
In industry, 74% of the energy consumed is used in the form of heat. The food sector is characterised by a high share of processes that rely on industrial heat [1]. However, 90% of this thermal energy currently comes from fossil fuels, and only 9% is supplied by renewable sources [2]. The adoption of solar thermal technologies in the food industry offers multiple benefits that support its viability as an energy alternative to overcome this caveat. Firstly, by relying on a renewable and stable source. Manufacturers can reduce production costs and limit their exposure to the volatility of fossil fuel prices, thereby ensuring greater long-term price stability and predictability [3]. These reductions in energy costs may also be reflected in lower prices for the end consumer. Solar-assisted dehydration enables a decrease in moisture content, thereby limiting microbial growth and food spoilage [3]. In this regard, Solar Heat for Industrial Processes (SHIP) may also address food security concerns as storage losses are estimated to reach up to 20%, posing a critical challenge to food security [4].
The installation of in-situ pre-dehydration systems near harvesting zones provides clear benefits for energy efficiency and product quality. The Iberian Peninsula, notably, benefits from very high solar radiation, with many clear-sky days and extended sunlight periods, making it particularly suitable for solar-based pre-dehydration systems. By lowering produce weight and moisture before transportation, these systems decrease fossil energy demand during both industrial drying and large-scale transport [5]. This approach reduces the final product cost, as demonstrated by an in-situ solar dryer used for acorns in Alentejo holm oak groves. The passive, indirect mobile dryer, fitted with hanging bags, reduces acorn moisture content by 15% after 72 hours of drying, delays fruit spoilage, and cuts large-scale industrial heat input [6,4]. Thermal energy data from a factory case at Landratech, an acorn food producer involved in the MEDACORNET project, indicate that 15% in-situ pre-dehydration cuts thermal energy use by 52% during both initial and final drying stages of acorn flour manufacture [3]. This combined method lowers fossil fuel use, reduces losses, improves energy efficiency, and supports sustainability in the food processing sector.
Natural solutions for grape pathogen control: chemical analysis and bioactivity evaluation of plant extracts
Publication . Ardohain, Elizandra; Marx, Ítala; Rodrigues, Paula; Afonso, Andreia; Oliveira, Izamara; Pires, Tânia C.S.P.; Barros, Lillian; Heleno, Sandrina A.
Peels from orange (Citrus sinensis L.) are often considered processing waste. Citrus peels contain bioactive compounds such as organic acids that have important biological properties
[1]. In addition, fennel (Foeniculum vulgare Mill.) and sage (Salvia officinalis L.) are widely used herbs that have been used for medicinal purposes and human consumption for centuries.
The leaves of these herbs contain polyphenols, which are antioxidant and antifungal compounds such as flavonoids [2,3]. To explore the potential of these plants as natural antifungals, this study aimed to analyze the phenolic compounds in extracts of fennel and sage leaves using HPLC-DAD/ESI-MS, after a maceration process. The study also evaluated the organic acids present in orange peels using HPLC-DAD. Finally, the antimicrobial potential of the plant extracts against food contaminants, including grapevine pathogens such as Botrytis cinerea, was tested using the microdilution method. This study found that the highest concentration of polyphenols in the leaves of sage and fennel were the flavonoids luteolin-7-O-glucuronide and quercetin-3-O-glucuronide, respectively. Sage leaves extract contained 69% of flavonoids and 31% of phenolic acids, while fennel leaves extract was richer in phenolic acids, corresponding to 61%, and the flavonoids were found in lower concentrations, corresponding to 39% of total phenolic composition. The concentration of organic acids in orange peels was 8±0.1g/100g dw, with citric acid being the main compound found, corresponding to 75%, while ascorbic acid corresponding to 18% of total organic acids determined. In this study, oxalic and quinic acids were also found in orange peels extract. All plant extracts demonstrated the ability to inhibit the growth of B. cinerea at a concentration of 10 mg/mL, indicating their potential as natural antifungals against this grapevine pathogen. Thus, these plant extracts have the potential to act as natural antimicrobials, showing promising results for disease control in grapevines. In this sense, the valorization of these plant extracts could generate significant economic benefits for the wine industry.