Physical and biological properties of alginate-based cinnamon essential oil nanoemulsions: Study of two different production strategies.

Nanoemulsions are a promising alternative for essential oil incorporation into active coatings. The influence of the preparation steps order on nanoemulsions' physical properties is still little explored. This study aimed to analyze the effect of the sequence of preparation steps and of the oil and polymer concentration on the stability, physical properties, and antifungal activity of alginate-based cinnamon essential oil nanoemulsions. The nanoemulsions were produced by two strategies: (I) preparation directly into an alginate solution (Ultra-Turrax at 10,000 rpm for 5 min + Ultrasound 150 W for 3 min); and (II) preparation in water (Ultra-Turrax at 10,000 rpm for 5 min + Ultrasound 150 W for 3 min) followed by homogenization with a sodium alginate solution (Ultra-Turrax at 10,000 rpm for 1, 3 or 5 min). The nanoemulsion prepared by the second strategy showed better stability, physical properties, and antifungal activity. In general, the presence of alginate hindered the cavitation effects of ultrasound, leading to the increase of droplets size and consequently affecting emulsions stability, turbidity, and antifungal properties.

Fast and sustainable production of smart nanofiber mats by solution blow spinning for food quality monitoring: Potential of polycaprolactone and agri-food residue-derived anthocyanins.

The shelf life of perishable foods is estimated through expensive and imprecise analyses that do not account for improper storage. Smart packaging, obtained by agile manufacturing of nanofibers functionalized with natural pigments from agri-food residues, presents promising potential for real-time food quality monitoring. This study employed the solution blow spinning (SBS) technique for the rapid production of smart nanofiber mats based on polycaprolactone (PCL), incorporating extracts of agricultural residues rich in anthocyanins from eggplant (EE) or purple cabbage (CE) for monitoring food quality. The addition of EE or CE to the PCL matrix increased the viscosity of the solution and the diameter of the nanofibers from 156 nm to 261-370 nm. The addition of extracts also improved the mechanical and water-related properties of the nanofibers, although it reduced the thermal stability. Attenuated total reflectance Fourier-transform infrared spectroscopy confirmed the incorporation of anthocyanins into PCL nanofibers. Nanofiber mats incorporated with EE or CE exhibited visible color changes (ΔE ≥ 3) in response to buffer solutions (pH between 3 and 10), and ammonia vapor. Smart nanofibers have demonstrated the ability to monitor fish fillet spoilage through visible color changes (ΔE ≥ 3) during storage. Consequently, smart nanofibers produced by the SBS technique, using PCL and anthocyanins from agro-industrial waste, reveal potential as smart packaging materials for food.

Chitosan-based nanocomposite films with carnauba wax, rosin resin, and zinc oxide nanoparticles.

This work aimed to develop edible emulsion-based barriers in the form of chitosan composite films, with a focus on assessing the impacts of carnauba wax, rosin resin, and zinc oxide nanoparticles on their properties. Six films were produced by casting using chitosan as polymer base and glycerol as plasticizer. Acetic acid and polysorbate 80 were also used to facilitate the dissolution and mixing of the components. The six filmogenic solutions contained chitosan at 1.2% w/v, wax or resin content with 0 or 0.6% m/v and ZnO with 0 or 0.05% m/v. The dried films were characterized according to their chemical, barrier, mechanical, thermal and optical properties. All treatments resulted in flexible films. Chitosan films appeared smoother and more uniform under SEM imaging, while carnauba wax films displayed roughness due to their hydrophobic nature. Wax and resin films were less transparent and water soluble than the chitosan-only films. On the other hand, the addition of ZnO in the formulations increased the solubility of the films. The sorption degree was in line with the solubility results, i.e., films with ZnO presented higher sorption degree and solubility values. All treatments showed low or non-light UV transmission, indicating that the films provide good barrier to UV light. In the visible light region, films of resin with ZnO showed the lowest transmittance values, hence offering a good barrier to visible light. Among the evaluated films, chitosan, and resin films with ZnO nanoparticles were more rigid and resistant to deformation. Overall, films produced with rosin resin and ZnO nanoparticles showed potential improvements in barrier, mechanical, thermal, and optical properties, mainly due to their low water solubility, good UV protection and low permeability to water vapor and oxygen, which are suitable for using in formulations, intended to produce edible films and coatings.

Red wine processing-derived Brazilian Alicante bouschet grape skin as a promising ingredient for cereal bars production.

Grape skin is a wine by-product with a high fiber and phenolic compound content, with potential application as an ingredient in food products. This work aimed to study the hedonic and sensory perception of the consumer using the Check-all-that-apply about cereal bars made with grape skin flour (GSF) obtained from wine residue. Grape skin flour with different granulometric ranges (coarse and fine) was added to the cereal bars in different proportions (10, 15, and 20%) to replace the oat flakes present in the formulation. Sensory acceptance results showed that all bars had good acceptance scores (>6.42) and presented different sensory profiles. The cereal bar containing 15% of coarse GSF had good sensory acceptance with attributes "few dark spots," "light color," and "softer," with desirable sensory characteristics and from the nutritional point of view with high fiber content and bioactive compounds and it was considered the best formulation. Therefore, the incorporation of wine by-products in cereal bars showed excellent acceptability and the possibility of insertion in the market.

Microencapsulation of marjoram essential oil as a food additive using sodium alginate and whey protein isolate.

Encapsulation techniques are generally used to preserve the volatile compounds of essential oils. This study aimed to evaluate the influence of process variables on the microencapsulation of marjoram essential oil (MEO) (Origanum majorana L.) by ionic gelation. The effect of sodium alginate concentration (0.5-2 g/100 mL), emulsifier concentration (0.5-2 g/100 mL whey protein isolate (WPI)), and cationic bath concentration (0.05-0.3 mol/L CaCl2) on the emulsions and beads properties were investigated, according to a rotatable central composite design. MEO chemical composition and antimicrobial activity were assessed. Emulsions were characterized for droplet size and viscosity, while the particles were analyzed for encapsulation efficiency, size and circularity, and morphology. High concentrations of alginate and WPI intensified the porous structure of the beads, reducing droplet mean diameter and encapsulation efficiency. High alginate concentrations also increased emulsion viscosity, affecting positively beads' circularity. The intermediate concentration of sodium alginate (1.25 g/100 mL), WPI (1.25 g/100 mL), and CaCl2 (0.175 mol/L) were selected as the most appropriate conditions to produce beads with satisfactory circularity and high encapsulation efficiency.

Anthracnose Controlled by Essential Oils: Are Nanoemulsion-Based Films and Coatings a Viable and Efficient Technology for Tropical Fruit Preservation?

Post-harvest diseases can be a huge problem for the tropical fruit sector. These fruits are generally consumed in natura; thus, their integrity and appearance directly affect commercialization and consumer desire. Anthracnose is caused by fungi of the genus Colletotrichum and affects tropical fruits, resulting in lesions that impair their appearance and consumption. Antifungals generally used to treat anthracnose can be harmful to human health, as well as to the environment. Therefore, essential oils (EO) have been investigated as natural biofungicides, successfully controlling anthracnose symptoms. The hydrophobicity, high volatility, and oxidative instability of essential oils limit their direct application; hence, these oils must be stabilized before food application. Distinct delivery systems have already been proposed to protect/stabilize EOs, and nanotechnology has recently reshaped the food application limits of EOs. This review presents robust data regarding nanotechnology application and EO antifungal properties, providing new perspectives to further improve the results already achieved in the treatment of anthracnose. Additionally, it evaluates the current scenario involving the application of EO directly or incorporated in films and coatings for anthracnose treatment in tropical fruits, which is of great importance, especially for those fruits intended for exportation that may have a prolonged shelf life.

Lycopene-rich watermelon concentrate used as a natural food colorant: Stability during processing and storage.

A lycopene-rich watermelon (Citrullus lanatus) concentrate was incorporated into snack cracker, fusilli pasta, and extruded snacks for coloring purposes. Changes in the L* and a* color coordinates and in the lycopene content were evaluated before and after thermal processes and monitored through 90 days of storage at ambient temperature. The products with the maximum lycopene degradation during processing were snack cracker and extruded snack (between 30 and 45%) whereas no degradation was observed in the fusilli pasta, except during cooking into boiling water (reduction up to 41%). The change in color during processing varied substantially depending on the product, but, in general, thermal treatments applied reduced the a* values (less reddish). The degradation kinetics of the lycopene and the color during storage followed first-order kinetics, with a half-life time of 25 to 315 days for lycopene content and 65 to 210 days for a* coordinate. Snack cracker was the most stable and had more than a 4-month period before losing half of the pigment content.