Improving the Properties of Gelatin-Based Films by Incorporation of "Pitanga" Leaf Extract and Crystalline Nanocellulose.

Biopolymer-based films can be activated by the incorporation of active compounds into their matrix. Plant extracts are rich in phenolic compounds, which have antimicrobial and/or antioxidant properties. The aim of this study was to produce gelatin-based active films and nanocomposite films incorporated with "pitanga" (Eugenia uniflora L.) leaf extract (PLE) and/or crystalline nanocellulose extracted from soybean straw (CN), and to study the physicochemical, functional, microstructural, thermal, UV/Vis light barrier, and antioxidant properties of these materials. PLE enhanced some film properties, such as tensile strength (from 30.2 MPa to 40.6 MPa), elastic modulus (from 9.3 MPa to 11.3 MPa), the UV/Vis light barrier, and antioxidant activity, in addition to affecting the microstructural, surface, and color properties. These improvements were even more significant in nanocomposites simultaneously containing PLE and CN (59.5 MPa for tensile strength and 15.1 MPa for elastic modulus), and these composites also had lower moisture content (12.2% compared to 13.5-14.4% for other treatments) and solubility in water (from 48.9% to 44.1%). These improvements may be the result of interactions that occur between PLE's polyphenols and gelatin, mainly in the presence of CN, probably due to the formation of a stable PLE-CN-gelatin complex. These results are relevant for the food packaging sector, as the activated nanocomposite films exhibited enhanced active, barrier, and mechanical properties due to the presence of PLE and CN, in addition to being entirely produced with sustainable components from natural and renewable sources.

Grape Pomace Rich-Phenolics and Anthocyanins Extract: Production by Pressurized Liquid Extraction in Intermittent Process and Encapsulation by Spray-Drying.

A considerable number of grape pomaces are generated annually. It represents a rich source of bioactive compounds, such as phenolic compounds and anthocyanins. Pressurized liquid extraction (PLE) has emerged as a green technology for recovering bioactive compounds from vegetal matrixes. In our study, PLE parameters (temperature, number of cycles, and rinse volume) have been studied to produce grape pomace extracts with high bioactive content using an experimental design. The experimental data obtained were adjusted to linear and quadratic models. The first-order model was better in predicting anthocyanins contents (TA, R2 = 0.94), whereas the second-order model was predictive for total phenolic compounds (TPC, R2 = 0.96). The main process parameter for the recovery of bioactive compounds was temperature, and the results showed opposing behaviors concerning TPC and TA, as it is difficult to optimize conditions for both. The extract containing the higher concentration of TPC (97.4 ± 1.1 mg GAE/g, d.b.) was encapsulated by spray-drying using maltodextrin as wall material. Particles presented with a spherical shape (~7.73 ± 0.95 µm) with a recovery yield of 79%. The results demonstrated that extraction followed by encapsulation of grape pomace extract is a good strategy to simplify future applications, whether for food, cosmetics or pharmaceutical fields.

Strontium Carbonate and Strontium-Substituted Calcium Carbonate Nanoparticles Form Protective Deposits on Dentin Surface and Enhance Human Dental Pulp Stem Cells Mineralization.

Strontium acetate is applied for dental hypersensitivity treatment; however, the use of strontium carbonates for this purpose has not been described. The use of Sr-carbonate nanoparticles takes advantage of both the benefits of strontium on dentin mineralization and the abrasive properties of carbonates. Here in, we aimed to synthesize strontium carbonate and strontium-substituted calcium carbonate nanoparticles and test them as potential compounds in active dentifrices for treating dental hypersensitivity. For this, SrCO3, Sr0.5Ca0.5CO3, and CaCO3 nanoparticles were precipitated using Na2CO3, SrCl2, and/or CaCl2 as precursors. Their morphology and crystallinity were evaluated by electron microscopy (SEM) and X-ray diffraction, respectively. The nanoparticles were added to a poly (vinyl alcohol) gel and used to brush dentin surfaces isolated from human third molars. Dentin chemical composition before and after brushing was investigated by infrared spectroscopy (FTIR) and X-ray dispersive energy spectroscopy. Dentin tubule morphology, obliteration, and resistance of the coatings to acid attack were investigated by SEM and EDS. The cytotoxicity and ability of the particles to trigger the mineralization of hDPSCs in vitro were studied. Dentin brushed with the nanoparticles was coated by a mineral layer that was also able to penetrate the tubules, while CaCO3 remained as individual particles on the surface. FTIR bands related to carbonate groups were intensified after brushing with either SrCO3 or Sr0.5Ca0.5CO3. The shift of the phosphate-related FTIR band to a lower wavenumber indicated that strontium replaced calcium on the dentin structure after treatment. The coating promoted by SrCO3 or Sr0.5Ca0.5CO3 resisted the acid attack, while calcium and phosphorus were removed from the top of the dentin surface. The nanoparticles were not toxic to hDPSCs and elicited mineralization of the cells, as revealed by increased mineral nodule formation and enhanced expression of COL1, ALP, and RUNX2. Adding Sr0.5Ca0.5CO3 as an active ingredient in dentifrices formulations may be commercially advantageous since this compound combines the well-known abrasive properties of calcium carbonate with the mineralization ability of strontium, while the final cost remains between the cost of CaCO3 and SrCO3. The novel Sr0.5Ca0.5CO3 nanoparticles might emerge as an alternative for the treatment of dental hypersensitivity.

Chitosan suspension as extractor and encapsulating agent of phenolics from acerola by-product.

The polymeric suspension of chitosan (Ch) has been an effective media for the extraction of total phenolic compounds (TPC) from the acerola by-product. It facilitates the subsequent production of nanoparticles loaded with the phenolics (Np-TPC) by ionic gelation. However, neither the effects of Ch concentration on encapsulation efficiency (EE%) of TPC nor which compounds are extracted in its media are known, being it the first objective of this study. The second objective was to analyze the stability of the Np-TPC under accelerated conditions and its release profile at pHs 3.0 and 7.0. The results showed that Ch does not affect the extraction of TPC. However, the EE increased from 35.0 to 48.1 % with the increase of Ch concentration (0.4 to 1.0 %). LC/ESI-QTOF MS analysis showed that phenolic acids and flavonoids are extracted in 0.8 % Ch medium. After encapsulation, microscopy images revealed particle sizes ranging between 110 and 150 nm. Additionally, the presence of phenolics did not change the stability of the particles under accelerated conditions and the actives were fully released into the released medium for 10 h. The Np-TPC suspension appears to be useful for the production of edible antioxidant coatings to preserve fruits/vegetables, with potential application as carrier of other food ingredients.

Investigation on brewer's spent yeast as a bio-vehicle for encapsulation of natural colorants from pumpkin (Cucurbita moschata) peels.

Brewer's spent yeast (BSY) Saccharomyces cerevisiae has been explored as a bio-vehicle for the encapsulation of bioactive compounds and as a delivery system. The main objectives of this work were to encapsulate carotenoids from pumpkin peel extract using BSY as an encapsulating agent and to evaluate the influence of ultrasound treatment on the carotenoid incorporation, stability and release. The powders produced by atomization of the suspension of BSY in the extract from pumpkin peels showed physical and microbiological stability during storage, presenting low values of water activity (<0.406), moisture content (<7.0%) and hygroscopicity (<6.8 g per 100 g), characteristics of greatest importance for powder formulations. Regarding the chemical stability of the incorporated carotenoids, there was a decline in carotenoid content in the first 30 days (p ≤ 0.01), although stabilization was achieved up to the 75th day. The best retention of carotenoids (273.3 µg g-1 of particles) was obtained by applying ultrasound treatment before atomization, which probably led to the adsorption of carotenoids onto yeasts. Ultrasound also showed a positive effect on the color protection of powders during storage and on the protection of compounds under simulated gastrointestinal digestion. BSY released the carotenoids gradually during the digestion and higher carotenoid release occurred in the intestinal phase with bioaccessibility values of 26.9 and 30.3%. Yeasts are a suitable carrier material and show promising characteristics for technological application.

TPP-chitosomes as potential encapsulation system to protect carotenoid-rich extract obtained from carrot by-product: A comparison with liposomes and chitosomes.

The objectives of this study were to extract bioactive compounds from carrot by-products and evaluate their chemical stability after encapsulation in liposomes (L) coated either with chitosan (Ch) or using sodium tripolyphosphate for chitosan complexation (TPP-Ch). The main compounds quantified in this study were carotenoids and total phenolic compounds, which reached encapsulation efficiencies higher than 75%. The TPP-Ch charged with carrot extract showed greater particle size (90.5 nm) and zeta potential (+22 mV) than vesicles without coating (68.0 nm and -2 mV, respectively), indicating that liposomes were successfully coated with chitosan. Regarding results of the carotenoid's encapsulated stability, TPP-Ch particles were more efficient preventing their degradation in all the experimental conditions studied (40 and 70 °C). It is significant that loaded TPP-Ch particles demonstrated similar results for the stability of carotenoid-rich extracts in ethanol, which would therefore be suitable for application in food industry or any aqueous matrices.

Development of natural pigments microencapsulated in waste yeast Saccharomyces cerevisiae using spray drying technology and their application in yogurt.

Although Saccharomyces cerevisiae has shown potential utilization as a bio-vehicle for encapsulation, there are no reports about the functionality of natural colorants encapsulated using yeast cells. The main objectives of this study were to produce natural food coloring by encapsulating extracts from grape pomace (GP) and jabuticaba byproducts (JB) in brewery waste yeast and evaluate the functionality of the pigments by their incorporation into yogurts. Particles produced by the encapsulation of extracts from GP and JB in S. cerevisiae using 5% of yeast had the highest encapsulation efficiencies for both anthocyanins (11.1 and 47.3%) and phenolic compounds (67.5 and 63.6%), the highest concentration of both bioactives during storage and stable luminosity. Yogurts showed a pseudoplastic behavior and were considered weak gels. Colored yogurts had acceptance indexes between 73.9 and 81.4%. This work evidenced the utilization of enriched yeasts as coloring agents and interesting additives for the production of functional foods.

Gelatin/chitosan based films loaded with nanocellulose from soybean straw and activated with "Pitanga" (Eugenia uniflora L.) leaf hydroethanolic extract in W/O/W emulsion.

Mechanical properties of biopolymer films can be a limitation for their application as packaging. Soybean straw crystalline nanocelluloses (NC) can act as reinforcement load to improve these material properties, and W/O/W double emulsion (DE) as encapsulating bioactive agents can contribute to produce active packaging. DE droplets were loaded with pitanga leaf (Eugenia uniflora L.) hydroethanolic extract. The mechanical, physicochemical, and barrier properties, and the microstructure of gelatin and/or chitosan films incorporated with NC or NC/DE were determined by classical methods. Film antioxidant activities were determined by ABTS and DPPH methods. The incorporation of NC/DE in gelatin and/or chitosan films (NC/DE films) changed the morphology of these films, which presented more heterogeneous air-side surfaces and cross-sections. They presented rougher topographies, notably greater resistance and stiffness, higher barrier properties to UV/Vis light and higher antioxidant activity than the NC films. Moisture content, solubility in water and water vapor permeability decreased due to the presence of DE. Overall, the NC/DE films improved all properties, when compared to the properties of NC films or those of films with only DE, from a previously published study. In spite of not having antimicrobial activity against the studied bacteria, NC/DE films did display a great antioxidant activity.

Extraction of phenolic compounds from acerola by-products using chitosan solution, encapsulation and application in extending the shelf-life of guava.

Aiming the simplification of the production of chitosan nanoparticles as an encapsulating material, the primary approach of this study was to investigate the extraction of active compounds from acerola-pulp by-products directly in chitosan solution by using tip sonication. The results have shown that chitosan solution can be used as a good solvent, mainly for total phenolic compounds (TPC) extraction (1792.7 mg/100 g of dry by-product). The extract was submitted to ionic gelation process using, as counter-ion, the sodium tripolyphosphate to form loaded nanoparticles with TPC. The suspension was applied as protective coatings on the guavas. The nanoengineered coatings provided an effective barrier that delayed the maturation and maintained the green pigmentation for longer periods along with good firmness. To the best of our knowledge, this was the first study that uses chitosan solution as extraction solvent of TPC from food byproducts in order to facilitate the encapsulation process.

Utilization of grape pomaces and brewery waste Saccharomyces cerevisiae for the production of bio-based microencapsulated pigments.

This research approaches the utilization of brewery waste yeast Saccharomyces cerevisiae as a vehicle for the encapsulation and protection of phenolic compounds from Cabernet Sauvignon and Bordeaux grape pomace extracts. The main purpose of this research was to enrich the biomass of yeast to investigate its potential as a novel vehicle for further application as pigment or functional ingredient. The obtained powders presented characteristics appropriated for storage, such as low water activity (<0.289), hygroscopicity (<13.71 g/100 g) and moisture (<7.10%) and particle sizes lower than the sensory perceptible (<11.45 µm). This work proved that yeasts were loaded after spray-drying, thus, they might be considered as biocapsules. Furthermore, the bioaccessibility of encapsulated phenolic compounds from Bordeaux and Cabernet Sauvignon extracts was 34.96% and 14.25% higher compared to their respective free extracts, proving that yeasts are not only biocapsules of easy application, but also a biological material capable of protecting and delivering the compounds during gastrointestinal digestion.

Soybean straw nanocellulose produced by enzymatic or acid treatment as a reinforcing filler in soy protein isolate films.

This work is a comparative study of the application of mercerized soybean straw (MSS) and nanocellulose produced by acid (CNCs) or enzymatic hydrolysis (CNFs) as reinforcing fillers in soy protein isolate (SPI) films. CNCs presented average dimensions of about 10 nm-thick and 300 nm-long with a crystallinity index of 57%, whereas CNFs have similar diameters, though with greater lengths (>1 µm), lower crystallinity index (50%) and greater thermal stability. Incorporation of 5% of CNCs and CNFs (g/100 g of SPI) improved the SPI film tensile strength by 38 and 48% respectively, and decreased the SPI film elongation at break when compared to control films. The SPI-CNC films showed the lowest values for solubility, probably due to their higher crystallinity (63%). On the other hand, the water vapor permeability was solely reduced with CNF addition, which can be attributed to their higher aspect ratio (length/diameter) and a better incorporation into the protein matrix.

Chemical treatment and characterization of soybean straw and soybean protein isolate/straw composite films.

This work investigated changes in the chemical composition and structure of soybean straw (SS) treated with alkali (NaOH 5% and 17.5%) and bleached with hydrogen peroxide (H2O2) or sodium hypochlorite (NaOCl). Removal of the amorphous constituents increased the degree of crystallinity and the content of cellulose fibers particularly after reaction with high concentrations of alkali. Treatment with NaOH 17.5% contributed to the allomorph transition from cellulose I to II regardless of the bleaching agent, but H2O2 as bleaching agent promoted more effective delignification. This work also evaluated the potential use of treated and non-treated SS as reinforcement filler in soy protein isolate film (SPI). Films added with treated SS presented higher mechanical resistance, lower elongation at break, and lower solubility in water. Addition of non-treated SS did not affect the properties of the SPI film significantly. The low solubility and the reasonable water vapor permeability of the composite films make them suitable packaging materials for fresh fruit and vegetables.