Gelatin and/or chitosan-based films activated with “Pitanga” (Eugenia uniflora L.) leaf hydroethanolic extract encapsulated in double emulsion

Microencapsulation of Pitanga extract (Eugenia uniflora L.) by ionic gelation: Effect of wall material and fluidized bed drying

Pitanga (Eugenia uniflora L.) is a fruit native to Brazil with a large amount of bioactive compounds, antioxidant properties and attractive color. However, it is not yet well studied, despite its high availability. A technique that can improve its application and the stability of its compounds is microencapsulation. Therefore, this work aimed to develop microparticles using ionic gelation (IG), multiple emulsion and fluidized bed drying. The pitanga fruit extract presented high levels of phenolic compounds and antioxidant capacity. The encapsulation efficiency in terms of phenolic compounds ranged from 25.76 to 54.51 %. Microparticles showed D50 ranging from 455 to 676 μm. The temperature and drying time influenced the physicochemical characteristics of the microparticles as they were dried in a fluidized bed. Microparticles dried at a higher temperature, for a shorter time and with a higher final moisture content exhibited a higher concentration of phenolic compounds, lighter color, less agglomeration, but lower carotenoid content. These results demonstrate that the IG and fluidized bed drying process is a promising method to increase the commercialization of pitanga fruit. These techniques have increased the stability of the active compounds of this fruit and can enable its application in foods as a natural colorant and/or functional agent.

Preparation and physicochemical characterization of different biocomposite films blended with bacterial exopolysaccharide EPS MC-5 and bacteriocin for food packaging applications

The study aims to evaluate how bacteriocin and extracellular polymeric substances (EPS) can influence the development of active packaging for food. The components might enhance the performance of packaging materials in terms of their physicochemical properties and their effectiveness in preserving food. Bacteriocin and EPS exert a significant effect in blocking the transmission of UV and visible light radiations. The molecular stability among the different functional groups of the composite films was evaluated using FT-IR analysis. The MG5 film exhibited the lowest percentage of water solubility (11.27 %) and the highest antibacterial activity against L. monocytogenes and E. coli, with a zone of inhibition measured as 21.32 ± 0.76 and 18.81 ± 0.29 mm, respectively. The TGA results indicated a noteworthy level of thermal stability in the composite films. Specifically, the MG5 bacteriocin blended film exhibited an approved metal chelation activity and demonstrated superior antioxidant activity, as evidenced by enhanced DPPH and ABTS+ scavenging activities. The incorporation of bacteriocin enhanced the interactions among the film components, and surface roughness was greatly impacted as revealed by the FE-SEM analysis. MG5 film exhibited excellent biodegradability in the natural soil environment, according to a soil burial study. To sum up, MG5 films can be an effective food packaging material, particularly for fried or high-fat items that are prone to contamination from microorganisms.

Effect of gelatin and salicylic acid incorporated in chitosan coatings on strawberry preservation

Strawberries are highly prone to rapid post-harvest deterioration due to their high nutritional content and lack of protective peel, demanding the development of alternative preservation methods. This study evaluates chitosan (CH) edible coatings enhanced with gelatin (GE) and salicylic acid (SA) for extending shelf life while maintaining fruit quality. Through atomic force microscopy, it was demonstrated that GE and SA showed increased surface roughness, besides improved the ultraviolet barrier properties and reduced water vapor permeability. Over 14 days of storage (3.0 ± 1.0 °C), all coatings minimized weight loss, firmness reduction, and color changes while delaying total soluble solids and pH increases. The effectiveness of the CH (0.8 %) with GE (0.2 %) and SA (2 mM) coating was mainly determined by the reduction of the development of natural disease development (84.30 ± 3.62 %), whereas the physicochemical properties tend to be similar in the assessed formulations. Principal Component Analysis (PCA) was used to investigate the effects of the treatments on strawberry shelf life and to determine the correlations between the responses studied. Considering the variability of the dimensions of the responses, correlation coefficients were used to form the matrix and extract the eigenvalue. PCA showed that the properties of the strawberries change continuously regardless of the treatments and indicated that four principal components accounted for 82.7 % of data variability. This study demonstrates that coatings, combined with cold storage, offer an effective solution for extending the shelf life of strawberries while preserving their quality throughout storage.

Effect of microencapsulation on antioxidant activities of Eugenia punicifolia (Kunth) DC hydroethanolic extracts

Eugenia punicifolia (Kunth) DC (Myrtaceae) is a folk medicinal plant in the Brazilian Cerrado with antioxidant, anti-inflammatory, antinociceptive, antiulcerogenic activities, etc., usually attributed to its phenolic compounds. Since these compounds are sensitive to heat and light, and to increase their applications, Hydroethanolic Extracts E. punicifolia (HEEP, EtOH:H2O 70% v/v) were encapsulated by freeze-drying in xanthan gum (mesh 80, HEEPX80; mesh 200, HEEPX200) in ratio 1:1(w/w). Flavonoids had the highest encapsulation efficiency in HEEPX80, with a total flavonoid content of 55.56%. The release profile at different pH levels showed that pH = 4.5, a relevant antioxidant activity for HEEPX80 and HEEPX200. Also, in HEEP-modified release, higher antioxidant activity was observed in more acidic media (pH 4.5) than in a more neutral medium (pH 7.4). From these results, we could infer that HEEP encapsulations with Xanthan gum could be a good alternative for preserving antioxidants in these extracts.

Eco-friendly film with highly efficient sterilization for food preservation by incorporating natural products into starch/polyvinyl alcohol matrix

An advanced biodegradable packaging film with antimicrobial and fresh-maintaining functions was constructed by incorporating berberine and L-arginine into the starch/polyvinyl alcohol (PVA) film matrix. The film was endowed with a dual antibacterial capacity thanks to the intrinsic antibacterial capability of berberine and cascaded photodynamic sterilization. The aggregated berberine presents an excellent photodynamic activity to generate reactive oxygen species (ROS), which further triggers the NO release from L-arginine. Under the synergetic action of ROS and NO, the as-prepared film not only has an antibacterial efficiency of over 99 % against both S. aureus and E. coli but also delays fruit ripening through antagonistic effects on ethylene to extend the shelf life of food. Meanwhile, the as-prepared film presents UV-shielding properties, thermal stability, and considerable mechanical properties. Specifically, the packaging film exhibits good biocompatibility and is biodegradable, with a degradation rate of 56 % within 16 days, which has great potential for improving food safety and environmental events.

The amazing native Brazilian fruits

A number of native Brazilian plant species are under exploited by the scientific community, despite the country's precious biodiversity. The vast majority of native Brazilian fruits (NBF) is source of compounds that provide many health benefits and can potentially be used to prevent diseases and formulate high-added value products. This review covers the scientific research over the last decade (2012-2022) on eight NBF, and focuses on information about the production and market panorama, physical description, physicochemical characterization, nutritional composition, their functional value of bioactive compounds and health benefits, as well as the potential for utilizations for each. The studies herein compiled reveal the outstanding nutritional value of these NBF. They are sources of vitamins, fibers, minerals and bioactive compounds that exhibit antioxidant activity, and they contain phytochemicals with anti-inflammatory action, anti-obesity and other functions that bring many health benefits to consumers. NBF can be also used as raw material for multiple products such as nectars, juices, jams, frozen pulps, liquor, among others. The dissemination of knowledge about NBF has fundamental implications worldwide.

Bacterial nanocellulose-based nanopaper activated by β-cyclodextrin/ Salvia officinalis essential oil complexes for shelf life extension of shrimp

Active bacterial nanocellulose (BNC) nanopapers containing Salvia officinalis essential oil (SEO) in free form and encapsulated with β-cyclodextrin (βCD) were prepared, and their effect on the shelf life extension of shrimp was investigated. The GC-MS analysis of the SEO indicated the presence of various active compounds such as Thujone (21.53 %), Ledol (12.51 %) and Eucalyptol (11.28 %) in the essential oil composition. The cytotoxicity of the SEO and SEO-βCD complexes in the L929 cell line was quite low. FTIR analysis revealed new interactions in the nanopapers containing SEO-βCD complexes. Microscopic images showed that SEO-βCD complexation improved the surface morphology of the BNC nanopapers, whereas free SEO had a negative effect. X-ray diffraction patterns of the nanopapers showed higher crystallinity of the SEO-βCD containing nanopapers than that of the SEO-incorporated nanopapers. Moreover, the addition of the SEO-βCD complex improved the thermal properties of the BNC nanopaper. Water contact angle analysis showed higher hydrophobicity of the samples containing free SEO than that of the other samples. Both SEO-βCD and free SEO increased the elongation at break and decreased the tensile strength of the nanopaper. The prepared active films showed a greater antimicrobial effect on L. monocytogenes than on E. coli. The results showed a higher antioxidant capacity of the free SEO-containing nanopapers (58-78 %). The desirable effects of the active nanopapers on shrimp preservation were demonstrated by the results obtained for the microbial load, pH, and volatile nitrogen content of the product. The results demonstrate the potential of the prepared BNC active nanopapers for use in active antioxidant/antimicrobial food packaging.

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.

Spray dried acerola (Malpighia emarginata DC) juice particles to produce phytochemical-rich starch-based edible films

This study aimed to produce spray dried acerola juice microparticles with different protein carriers to be incorporated into edible starch films. The microparticles were evaluated for solids recovery, polyphenol retention, solubility, hygroscopicity, particle size distribution, X-ray diffraction, phytochemical compounds and antioxidant activity. Acerola microparticles produced with WPI/hydrolysed collagen carriers (AWC) with higher solids recovery (53.5 ± 0.34% w/w), polyphenol retention (74.4 ± 0.44% w/w), high solubility in water (85.2 ± 0.4% w/w), total polyphenol content (128.45 ± 2.44 mg GAE/g) and good storage stability were selected to produce starch-based films by casting. As a result, cassava films with water vapour permeability of 0.29 ± 0.07 g mm/m2 h KPa, polyphenol content of 10.15 ± 0.22 mg GAE/g film and DPPH radical scavenging activity of 6.57 ± 0.13 μM TE/g film, with greater migration of polyphenol to water (6.30 ± 0.52 mg GAE/g film) were obtained. Our results show that the incorporation of phytochemical-rich fruit microparticles is a promising strategy to create biodegradable edible films.

An Updated Comprehensive Overview of Different Food Applications of W1/O/W2 and O1/W/O2 Double Emulsions

Double emulsions (DEs) present promising applications as alternatives to conventional emulsions in the pharmaceutical, cosmetic, and food industries. However, most review articles have focused on the formulation, preparation approaches, physical stability, and release profile of encapsulants based on DEs, particularly water-in-oil-in-water (W1/O/W2), with less attention paid to specific food applications. Therefore, this review offers updated detailed research advances in potential food applications of both W1/O/W2 and oil-in-water-in-oil (O1/W/O2) DEs over the past decade. To this end, various food-relevant applications of DEs in the fortification; preservation (antioxidant and antimicrobial targets); encapsulation of enzymes; delivery and protection of probiotics; color stability; the masking of unpleasant tastes and odors; the development of healthy foods with low levels of fat, sugar, and salt; and design of novel edible packaging are discussed and their functional properties and release characteristics during storage and digestion are highlighted.

Formation Mechanism of Starch-Based Double Emulsions from the Interfacial Perspective

Double emulsions are of significant practical value in protecting the core material owing to their multicomponent structure and have thus been applied in various fields, such as food, cosmetics, and drugs. However, the mechanism of double emulsion formation by native starch is not well established. Herein, we demonstrate a facile route to develop type-A, type-B, and type-C double emulsions using native starch and develop an innovative design for a carrier. Interfacial interaction, enthalpy changes of starch, and interfacial properties are key factors governing the formation of double emulsions and controlling the type of double emulsions formed. Therefore, the results of this study provide a better understanding of how and what type of starch-based double emulsions are formed.

Open roads and bridge: Preservation of fresh beef by a packaging film constructed from photosensitizing bacterial cellulose

Food packaging is now widely used in everyday life to protect food from certain environmental factors. In this work, we have successfully prepared a bacterial cellulose/chitosan-TPE-COOH composite film (BC/CS-TPE), which can achieve broad-spectrum killing of bacteria through a variety of antibacterial mechanisms and ensure the freshness of the beef. In this complex film, CS acts as "advance team", responsible for breaking through the cell wall or outer membrane of bacteria, while the reactive oxygen species produced by photosensitizer under irradiation attacks bacteria, further increasing the destructive effect on the bacterial cell membrane. This allows the film to have outstanding antibacterial properties that can kill 108 CFU/mL pathogens in 10 min. At the same time, cell experiments and hemolysis experiments proved that the film has good biocompatibility. Therefore, BC/CS-TPE film, as the efficient functional food packaging film, has a broad future application prospect.

Films Based on Biopolymers Incorporated with Active Compounds Encapsulated in Emulsions: Properties and Potential Applications-A Review

The rising consumer demand for safer, healthier, and fresher-like food has led to the emergence of new concepts in food packaging. In addition, the growing concern about environmental issues has increased the search for materials derived from non-petroleum sources and biodegradable options. Thus, active films based on biopolymers loaded with natural active compounds have great potential to be used as food packaging. However, several lipophilic active compounds are difficult to incorporate into aqueous film-forming solutions based on polysaccharides or proteins, and the hydrophilic active compounds require protection against oxidation. One way to incorporate these active compounds into film matrices is to encapsulate them in emulsions, such as microemulsions, nanoemulsions, Pickering emulsions, or double emulsions. However, emulsion characteristics can influence the properties of active films, such as mechanical, barrier, and optical properties. This review addresses the advantages of using emulsions to encapsulate active compounds before their incorporation into biopolymeric matrices, the main characteristics of these emulsions (emulsion type, droplet size, and emulsifier nature), and their influence on active film properties. Furthermore, we review the recent applications of the emulsion-charged active films in food systems.

Effects of pre-emulsion prepared using sucrose esters with different hydrophile-lipophile balances on characteristics of soy protein isolate emulsion films

The preparation of emulsion films using pre-emulsification has received extensive attention due to the enhancement of oil binding capacity. However, the different effects of water in oil (W/O) and oil in water (O/W) pre-emulsions on the physicochemical properties of films are still unclear. Therefore, the soy protein isolate (SPI) based emulsion films were prepared by W/O or O/W pre-emulsion using sucrose esters with different hydrophile-lipophile balances to investigate the properties of SPI emulsion (SPIE) films. The viscosity, storage moduli, and loss moduli of film-forming solutions (FFSs) with O/W pre-emulsion were higher than those of FFSs with W/O pre-emulsion. The oil droplets of FFSs with W/O pre-emulsion were large and uneven, and the oil droplet size increased after drying. Phase separation and macroporous network appeared in cross-sectional of SPIE films with W/O pre-emulsion according to scanning electron microscope images. Meanwhile, the SPIE films with W/O pre-emulsion demonstrated higher oil concentration and hydrophobicity on the upper surface compared with the SPIE films with O/W pre-emulsion. Low tensile strength, glass transition temperature, and high elongation at break and transparency value of SPIE films with O/W pre-emulsions were founded. The water vapor permeability of SPIE films with W/O pre-emulsion increased with the addition of oil, whereas the opposite trend appeared in that with O/W pre-emulsion. In conclusion, the structure and porosity of emulsion films could be affected by the pre-emulsion types, which can determine the application ranges.

Rheological and Viscoelastic Properties of Chitosan Solutions Prepared with Different Chitosan or Acetic Acid Concentrations

Chitosan (Ch) is a partially crystalline biopolymer, insoluble in pure water but soluble in acid solutions. It has attracted interest from researchers to prepare solutions using different acid types and concentrations. This research aims to study both the effect of chitosan (Ch) or acetic acid (Ac) concentrations, at different temperatures, on rheological and viscoelastic properties of Ch solutions. To study the effect of Ch, solutions were prepared with 0.5−2.5 g Ch/100 g of solution and Ac = 1%, whereas to study the effect of Ac, the solutions were prepared with 2.0 g of Ch/100 g of solution and Ac = 0.2−1.0%. Overall, all analyzed solutions behaved as pseudoplastic fluid. The Ch strongly affected rheological properties, the consistency index (K) increased and the index flow behavior (n) decreased as a function of Ch. The activation energy, defined as the energy required for the molecule of a fluid to move freely, was low for Ch = 0.5%. The effect of Ac was less evident. Both K and n varied according to a positive and negative, respectively, parabolic model as a function of Ac. Moreover, all solutions, irrespective of Ch and Ac, behaved as diluted solutions, with G” > G’. The relaxation exponent (n”) was always higher than 0.5, confirming that these systems behaved as a viscoelastic liquid. This n” increased with Ch, but it was insensitive to Ac, being slightly higher at 45 °C.

Effects of Additional Polyvinyl Alcohol (PVA) on the Physiochemical Properties of Chitosan-Glutaraldehyde-Gelatine Bioplastic

This study investigated the effects of additional PVA on the physicochemical properties of the chitosan-glutaraldehyde/gelatin bioplastic composite. The best results of the bioplastic film were obtained at a concentration of 3% PVA, with a tensile strength value of 3.3 MPa, flexibility reached 54%, a thickness value of 0.24 mm, percentage of inhibition against E. coli and S. aureus was 21.8% and 8.8% respectively. The FTIR spectrum results showed no change in the wavenumber of the chitosan and gelatin chitosan spectrum with OH, CO, and NH functional groups. The spectrum indicates that only physical interactions occurred. The bioplastics are similar in thermal stability and have slight differences in bioplastic morphological contours. The average thickness of the bioplastics is between 0.20–0.26 mm. Based on the Japanese Industrial Standard (JIS), all bioplastics meet the standard thickness, which is < 0.25 mm, excluding chitosan, which has a thickness of 0.26 mm. The addition of PVA into the bioplastics structure increased the hydrophobicity, pH resistance, and flexibility of bioplastics. Meanwhile, additional PVA decreased biodegradability, only degraded by 60% at eight weeks. Based on these data, not all bioplastics can meet the degradation time criteria set by the international bioplastic standard ASTM D-6002, that bioplastics must be 100% degraded within eight weeks. Bioplastics made from chitosan and chitosan-gelatin have been degraded by 90% for 48 weeks. Based on the antibacterial properties, the inclusion of PVA into the bioplastic structure enhances the antibacterial properties.

Fabrication and performance evaluation of pectin-fish gelatin-resveratrol preservative films

Resveratrol-loaded fish gelatin (FG)-low methoxyl pectin (LMP) composite films with different FG:LMP mass ratios were prepared and evaluated as food packaging materials. With increasing FG contents, the water solubility of the films decreased. Moreover, the UV (315-400 nm) blocking efficiency and opacity increased with increasing LMP contents. The elongation of the films at breaking and tensile strengths were adjusted using the ratio of FG and LMP. The lowest water vapour permeability was observed at an FG:LMP mass ratio of 2:1. All films exhibited good antioxidant properties and significantly delayed oil deterioration when used for beef tallow preservation. The release behaviour of resveratrol in 95% ethanol as a food simulant was determined by film composition. The fabricated films exhibit significant potential for beef tallow preservation applications. Furthermore, LMP can improve the stability of resveratrol-FG complexes and compete with resveratrol for binding FG to accelerate resveratrol release.

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.

Advances in biopolymeric active films incorporated with emulsified lipophilic compounds: a review

The attention towards active films has increased due to consumer demand for high-quality foods without chemical additives. Active biopolymer-based films have shown great potential for active films by impacting food safety, acting as the carriers of various natural antioxidant and antimicrobial compounds, and decreasing environmental pollution from petrol-derived packaging materials. However, there is a wide range of challenges concerning the different characteristics of biopolymers and plasticizers, often hygroscopic/hydrophilic, compared to numerous lipophilic bioactive compounds. Therefore, recent studies have focused on applying oil-in-water emulsion-based systems to enhance the lipophilic bioactive compounds' dispersibility into the film matrix, improving their performance. It is worth emphasizing that resulting complex systems give rise to new challenges such as (i) dispersion technology of the bioactive compounds with minimum adverse effects on its bioactivities, (ii) interactions between different components of the active films, giving rise to new physicochemical properties, and (iii) the change of the diffusion properties of bioactive compounds into the active films, resulting in different release properties. These challenges are profound and critically discussed in this review, as well as the encapsulation techniques employed in preparing emulsions loaded with lipophilic bioactive compounds for the active film development. An outlook of future directions in the research, development, and application of these active films are given.