Olimpia Pitirollo

The growing demand for natural and sustainable preservatives has renewed interest in essential oils (EOs) because of their potential antimicrobial and antioxidant activities. In this study, lemon, lavender, and oregano EOs, together with tomato and artichoke extracts, were evaluated against foodborne and spoilage microorganisms using an impedometric approach. Three bacterial strains (Listeria innocua, Escherichia coli, and Pseudomonas fluorescens) and two yeast strains (Zygosaccharomyces bailii and Kluyveromyces marxianus) were tested. Tomato and artichoke extracts showed no antimicrobial activity under the tested conditions, with MIC values higher than 66.67 µL/mL. Among the EOs, oregano EO showed the strongest antimicrobial properties, with both bacteriostatic and bactericidal effects, even at low concentrations for all tested strains. In contrast, lavender EO was the most effective against yeast, with MIC and MFC values of 0.75 µL/mL for both species. Antioxidant activity, assessed via DPPH and Oxitest assays, was highest for oregano EO, which showed a 95% total antioxidant capacity and an induction period of 1224 min. Overall, the results support the use of impedance-based methods as a rapid and informative tool for screening natural preservatives and identify oregano EO as the most promising multifunctional candidate, combining strong antibacterial and antioxidant properties.

Packaging has the main role of protecting a product during storage, and the material selected for packaging has a crucial role in shelf-life control. In recent years, according to the recent European regulations on plastics, different materials have been proposed with the aim of reducing the use of fossil-based packaging. In the present work, the storage of tomato by-product powders dried at different temperatures (40 and 70 °C), in different types of packaging (plastic bag, bioplastic bag, edible active film, and edible active film enriched with antioxidants) was monitored for 11 months. Several analytical approaches were used to characterize the properties of the product after drying treatment. Oxidative stability was evaluated through the Oxitest reactor; bioactive compounds content, such as total phenolic and percentage of total antioxidant capacity, were assessed through spectrophotometric assays; high-performance liquid chromatography coupled to mass spectrometry analysis was employed for β-carotene and lycopene contents monitoring. Results showed a progressive reduction in all parameters, with slight differences in the behavior of the aliquots stored in the different materials. Samples stored in bioplastic showed a higher retention of phenolic compounds and antioxidant capacity at early storage stages, whereas conventional plastic and active packaging exhibited comparable or improved performance at later stages, depending on the analytical parameter considered.

Oxidative stress is one of the main factors affecting food stability; therefore, antioxidant additives are generally used as food supplements for shelf-life improvement. In this work, the use of an antioxidant gel based on natural polysaccharides was tested on different types of meat, such as hamburger, beef steak, and horse fillet. The oxidative stability was measured on minced meat by Oxitest reactor, an automated tool performing accelerated shelf-life analysis by monitoring the fat oxidation process. The primary and secondary shelf-life of the gel was evaluated by DPPH assay. The effect of the gel on meat shelf-life was examined by colorimetry providing information about the color variation (∆E) during time. Treated meats showed lower color variation compared to untreated samples. Moreover, some color coordinates were selected as markers to follow the oxidation phenomenon. In conclusion, the antioxidant gel was found to preserve meat from oxidation, increasing stability during shelf-life.

The ecological transition is leading industry towards the use of materials of natural origin, which are often proposed for food contact materials as a sustainable solution to reduce plastic use. They are perceived as safe by consumers; however, a strict control on potential contaminants able to migrate to food and beverages is necessary to assess safety. Thus, the development of analytical methods for the detection and the identification of potentially occurring harmful substances is strongly encouraged, and the combination of different techniques can be a solution to obtain complementary information. In this work, GC-MS, HPLC-MS, ATR-IR and ESEM have been exploited with the aim of monitoring both volatile and non-volatile compounds, and to control surface composition and morphology. Extraction with solvent and migration experiments with simulants were performed on 11 commercial samples, including plates, caps, and wooden coffee stirrers. Global and specific migration studies were carried out, and possible differences before and after use were explored. Analysis after solvent extraction confirmed the presence of additives, and of Non-Intentionally-Added Substances (NIAS) that were also found in migration studies. Data on morphological characterisation were useful to control the item composition, and to check the stability of the materials after repeated use.

Background: “FODMAPs” (fermentable-oligo-, di-, monosaccharides, and polyols) are a group of fermentable carbohydrates and polyols largely diffused in food products. Despite their beneficial effects as prebiotics, people affected by irritable bowel syndrome manifest symptoms when eating these carbohydrates. A low-FODMAP diet seems to be the only possible therapy proposed for symptom management. Bakery products are a common source of FODMAPs, whose pattern and total amount can be affected by their processing. This work aims at studying some of the technological parameters that can influence the FODMAPs pattern in bakery products during the production process. Methods: high-performance anion exchange chromatography coupled to a pulsed amperometric detector (HPAEC-PAD) was used as a highly selective system for carbohydrates evaluation analyses on flours, doughs, and crackers. These analyses were performed using two different columns, the CarboPac PA200 and CarboPac PA1, which are selective for oligosaccharide and simple sugar separation, respectively. Results: emmer and hemp flours were selected to prepare doughs as they contained low oligosaccharide content. Two different mixes of ferments were used at different times of fermentation to evaluate the best conditions to achieve low-FODMAP crackers. Conclusion: the proposed approach allows carbohydrate evaluation during crackers processing and permits the selection of opportune conditions to obtain low-FODMAP products.

Mechanical properties of polymer biocomposites are influenced by the interaction between the matrix and the filler surface. In this work, composites based on poly(butylene-adipate-terephthalate) (PBAT) filled with micrometric particles of zein-TiO2 complex (ZTC) were realized via solvent casting technique at different concentrations, equal to 0, 5, 10, and 20 wt%. After pelletization, the resulting materials were injection molded into standard specimens, employed for the uniaxial tensile test (UTT) characterization. From the stress-strain curves, Young’s modulus ( E ), yield stress ( σ y ), stress at break ( σ B ), elongation at break ( ε B ), and toughness ( T ) were collected. The addition of the ZTC proved to show a reinforcing effect on the polymeric matrix, with an increase in both E and σ y . Modelling of the mechanical properties was performed by applying Kerner’s and Pukánszky’s equations. Kerner’s model, applied on experimental E values, returned a very good correspondence between collected and theoretical values. From the application of Pukánszky’s model to σ y , the obtained B value showed a good interfacial interaction between the matrix and the filler. Due to the enhanced stiffness of the composites, a reduction in the true stress at break ( σ T , B ) was observed. The modified Pukánszky’s model gave a B value lower than the one obtained for the yield, but still in the range of acceptable values for microcomposites.

The most common preservation process for chili peppers is drying, which inevitably causes oxidative degradation of thermolabile molecules. The aim of this research was to evaluate the potential protective effect exerted by an active ingredient based on grape seed oil, on pepper fruits. Grapeseed oil is rich in antioxidant compounds and was applied to pepper’s surface in form of a sol–gel product, before fruit thermal treatment. In this work, chili peppers samples were preventively treated with an active solution, and controls (untreated peppers), were submitted to a drying process performed at two different temperatures: 45 and 65 °C. Analysis of capsaicinoids, carotenoids, apocarotenoids, and phenolic content was performed to evaluate possible differences between the sets of samples. Oxidative stability of oil enriched with chili pepper powder aliquots was also measured to evaluate the antioxidant power of the samples. Obtained data showed that treated samples retained a higher amount of capsaicinoids and carotenoids. Oxidative stability of pepper powder was also higher for treated samples than for controls. Furthermore, the thermal treatment performed at 45 °C caused milder modifications than the 65 °C treatment. The applied pre-drying treatment can be proposed to prevent bioactive compounds loss and to enhance product stability and shelf-life.

In this work, new biodegradable composite materials based on poly (butylene adipate terephthalate) (PBAT) reinforced with zein–TiO₂ complex microparticles were prepared and characterised by electron microscopy and tensile and dynamic-mechanical tests. The composite pellets were prepared by solvent casting with different filler contents, namely 0, 5.3, 11.1 and 25 part per hundred resin (phr), to modify and modulate the properties of the final materials. Scanning electron microscopy (SEM) images showed homogeneous dispersion of the filler, without microparticles aggregation or phase separation between filler and matrix, suggesting a good interphase adhesion. According to tensile tests, Young’s modulus showed an improvement in the rigidity and the yield stress presented an increasing trend, with opposite behaviour compared to other composites. Dynamic-mechanical analysis (DMA) results exhibited increasing storage modulus values, confirming a greater rigidity with a higher filler percentage. The glass transition temperature showed a slightly increasing trend, meaning the presence of an interaction between the two phases of the composite materials. Overall, the produced PBAT composites showed similar properties to low-density polyethylene (LDPE), proving to be promising and more sustainable alternatives to traditional polymers commonly adopted in agri-food fields.