Smart labels based on polyvinyl alcohol incorporated with chitosan nanoparticles loaded with grape extract: Functionality, stability and food application.

Anthocyanins (ACNs) are natural compounds with potential applications due to their colorimetric response to pH. Due to their sensitivity to various environmental factors, nanoencapsulation with biopolymers is a successful strategy for stabilizing ACNs. In this work ACNs were extracted from grape skins and encapsulated into chitosan (CS) nanoparticles by ionic gelation using sodium tripolyphosphate (TPP) as a cross-linking agent. CS nanoparticles loaded with ACNs had particle sizes between 291 and 324 nm and polydispersity index around 0.3. The encapsulation efficiency of ACNs was approximately 60 %; and encapsulated anthocyanins (ACN-NPs) exhibited color change properties under different pH conditions. pH-sensitive labels based on polyvinyl alcohol (PVA) were prepared by the casting method. The effect of incorporating ACN-NPs on the physical, structural, and pH-sensitive properties of PVA labels was evaluated, and its application as shrimp freshness indicator was studied. The nanoencapsulation protected ACNs against heat and light treatments, preserving the original purple color. When applying the label, visible changes from red to blue until reaching yellow were observed with the change in the quality of the shrimp at the refrigeration temperature. The results suggest that PVA labels containing ACNs encapsulated in C-NPs can be used as smart packaging labels in the food industry.

Dual Modification of Cassava Starch Using Physical Treatments for Production of Pickering Stabilizers.

Cassava starch nanoparticles (SNP) were produced using the nanoprecipitation method after modification of starch granules using ultrasound (US) or heat-moisture treatment (HMT). To produce SNP, cassava starches were gelatinized (95 °C/30 min) and precipitated after cooling, using absolute ethanol. SNPs were isolated using centrifugation and lyophilized. The nanoparticles produced from native starch and starches modified using US or HMT, named NSNP, USNP and HSNP, respectively, were characterized in terms of their main physical or functional properties. The SNP showed cluster plate formats, which were smooth for particles produced from native starch (NSNP) and rough for particles from starch modified with US (USNP) or HMT (HSNP), with smaller size ranges presented by HSNP (~63-674 nm) than by USNP (~123-1300 nm) or NSNP (~25-1450 nm). SNP had low surface charge values and a V-type crystalline structure. FTIR and thermal analyses confirmed the reduction of crystallinity. The SNP produced after physical pretreatments (US, HMT) showed an improvement in lipophilicity, with their oil absorption capacity in decreasing order being HSNP > USNP > NSNP, which was confirmed by the significant increase in contact angles from ~68.4° (NSNP) to ~76° (USNP; HSNP). A concentration of SNP higher than 4% may be required to produce stability with 20% oil content. The emulsions produced with HSNP showed stability during the storage (7 days at 20 °C), whereas the emulsions prepared with NSNP exhibited phase separation after preparation. The results suggested that dual physical modifications could be used for the production of starch nanoparticles as stabilizers for Pickering emulsions with stable characteristics.

Starch nanoparticles containing phenolic compounds from green propolis: Characterization and evaluation of antioxidant, antimicrobial and digestibility properties.

This study investigated the production of nanoparticles through nanoprecipitation using cassava and potato starches as carriers to stabilize phenolic compounds (PC) from green propolis extract (PE). Additionally, the antioxidant and antimicrobial activities of PC stabilized with starch nanoparticles (SNPs), as well as their release under gastrointestinal conditions were investigated. PE exhibited antioxidant and antibacterial properties, especially PE3 (PE produced using sonication by 20 min and stirring at 30 °C for 24 h) had the highest concentrations of p-coumaric acid, rutin, kaempferol and quercetin. SNPs displayed bimodal distribution with particle size lower than 340 nm. The stabilization of PC increased surface charge and hydrophobicity in SNPs. Moreover, SNPs containing PC from PE exhibited antibacterial activity against Listeria monocytogenes, at a concentration of 750 mg/mL. Low release of PC was observed from the nanoparticles when exposed under simulated gastrointestinal conditions. These nanomaterials could be used as natural ingredients with antioxidant and antimicrobial properties.

Improving Ginger's Bioactive Composition by Combining Innovative Drying and Extraction Technologies.

Ginger extracts (GEs) are antioxidant, antimicrobial, and anti-inflammatory. Their bioactivity can benefit foods and active packaging by extending shelf life, enhancing safety, and providing health benefits. Highly bioactive GEs are crucial to formulating potent active products and avoiding negative effects on their properties. Sesquiterpenes and phenolics are the main bioactives in ginger, but drying and extraction affect their composition. GEs are usually obtained from dry rhizomes; however, these operations have been studied independently. Therefore, a combined study of innovative drying and extraction technologies to evaluate their influence on extracts' composition will bring knowledge on how to increase the bioactivity of GEs. The effects of an emergent drying (vacuum microwave, VMD) followed by an emergent extraction (ultrasound, UAE, 20 or 80 °C) were investigated in this work. Microwave extraction (MAE) of fresh ginger was also studied. Convective oven drying and Soxhlet extraction were the references. Drying kinetics, powder color, extract composition, and antioxidant activity were studied. While MAE preserved the original composition profile, VMD combined with UAE (20 °C) produced extracts richer in phenolics (387.6 mg.GAE/g) and antioxidant activity (2100.7 mmol.Trolox/mL), with low impact in the sesquiterpenes. VMD generated shogaols by its high temperatures and facilitated extracting bioactives by destroying cellular structures and forming pores. UAE extracted these compounds selectively, released them from cell structures, and avoided losses caused by volatilization and thermal degradation. These findings have significant implications, as they provide an opportunity to obtain GE with tailored compositions that can enhance the formulation of food, active packaging, and pharmacological products.

The mechanism, biopolymers and active compounds for the production of nanoparticles by anti-solvent precipitation: A review.

The anti-solvent precipitation method has been investigated to produce biopolymeric nanoparticles in recent years. Biopolymeric nanoparticles have better water solubility and stability when compared with unmodified biopolymers. This review article focuses on the analysis of the state of the art available in the last ten years about the production mechanism and biopolymer type, as well as the used of these nanomaterials to encapsulate biological compounds, and the potential applications of biopolymeric nanoparticles in food sector. The revised literature revealed the importance to understand the anti-solvent precipitation mechanism since biopolymer and solvent types, as well as anti-solvent and surfactants used, can alter the biopolymeric nanoparticles properties. In general, these nanoparticles have been produced using polysaccharides and proteins as biopolymers, especially starch, chitosan and zein. Finally, it was identified that those biopolymers produced by anti-solvent precipitation were used to stabilize essential oils, plant extracts, pigments, and nutraceutical compounds, promoting their application in functional foods.

Intelligent labels manufactured by thermo-compression using starch and natural biohybrid based.

This work aims to develop intelligent labels based on cassava starch and biohybrid pigments by thermo-compression. The biohybrid pigment (BH) was developed by the adsorption of anthocyanins (ACNs) extracted from the jambolan fruit (Syzygium cumini L.) into montmorillonite (Mt) in order to improve its stability. The effect of the addition of biohybrid on the physicochemical properties of the thermo-pressed starch labels was evaluated. ACNs from jambolan extract show a visible pH-dependent color-changing ability at pH 1 - 12, and the adsorption did not modify the color property. The intelligent labels presented a homogeneous surface, and the BH was well dispersed in the starch matrix. The presence of BH increased the solubility in the water of starch labels. Chemical structure characterization revealed that the BH interacted with starch matrices through hydrogen bonds. Furthermore, the thermal stability of starch labels increased with the presence of BH. Hence, the purple color of intelligent labels was preserved at high temperatures. Finally, labels containing BH show visible changes from purple to a blue color when exposed to ammonia vapor, which simulates the degradation of meat products. Thus, the label content jambolan pigments will be used to control meat deterioration.

Impact of drying and extractions processes on the recovery of gingerols and shogaols, the main bioactive compounds of ginger.

Ginger extracts have anti-inflammatory, antioxidant, antitumor, and antibacterial activities mainly due to gingerols and shogaols. Extract composition and functionality can be affected by drying and extraction processes. Alternative methods to obtain ginger extracts based on high contents of gingerols and shogaols have been reported. However, there were no studies that present a broad overview of how these methods affect the composition and functionalities of ginger extracts. Based on literature data from 2011 to 2022, this review shows how drying, extraction, and complementary processes (i.e., enzymatic, acidic, and carbonic maceration) affect the composition and bioactivity of the ginger extract. Lower temperature processes, including freeze-drying, cold ultrasound-, or enzyme-assisted extraction, lead to extracts richer in phenolics, gingerols, and antioxidant activity. On the other hand, acidic solvents or "hot" processes including microwave-drying, pressurized liquid, and microwave-assisted extraction can favor higher shogaols concentrations, which have higher antitumor, anti-inflammatory, and antimicrobial activities than the gingerols precursors. Thus, in this review, we analyzed and discussed the relation between ginger processing and their bioactive compounds, focusing especially on gingerols and shogaols, as well as the main processes that increase the content of 6-shogaol without compromising other phenolic compounds to produce highly functional extracts for future applications in the food packaging sector.

A review on TiO2-based photocatalytic systems applied in fruit postharvest: Set-ups and perspectives.

Titanium dioxide (TiO2) is a photocatalytic material used to degrade ethylene, and it has been studied as an alternative postharvest technology. Although several studies have indicated the effective action of TiO2 photocatalysis for delaying the fruit ripening, photocatalytic systems need to be well-designed for this application. Fruit is susceptible to environmental conditions like temperature, relative humidity, atmosphere composition and exposure to UV-light. This fragility associated with its variable ethylene production rate over its maturation stage limits the photocatalysis parameters optimization. Thus, this review aims to detail the reaction mechanisms, set-up, advantages, and limitations of TiO2 photocatalytic systems based on polymers-TiO2 nanocomposites and reactors containing TiO2 immobilized into inorganic supports designed for fruit applications. It is expected that this review can elucidate the fundamental aspects that should be considered for the use of these systems.

Ethylene scavenging properties from hydroxypropyl methylcellulose-TiO2 and gelatin-TiO2 nanocomposites on polyethylene supports for fruit application.

Several technologies have been proposed to preserve fruits and to avoid postharvest losses. The degradation of ethylene produced by the fruits using TiO2 photocatalysis has shown to be a good option to delay the ripening of fruits. This paper proposed a new application of biopolymers-TiO2 nanocomposites developed to extend the shelf-life of fruits. Photocatalytic coatings were applied on the expanded polyethylene foam nets to degrade ethylene. Gelatin and hydroxypropyl methylcellulose (HMPC) were tested as hydrophobic and hydrophilic matrices for the TiO2 incorporation. First, nanocomposite films prepared by casting were evaluated with regards to their photocatalytic properties. Both matrices, which were loaded with 1 wt% TiO2, degraded 40% of the ethylene injected in a batch reactor. By Langmuir-Hinshelwood model, ethylene degradation using gelatin-TiO2 films (kapp = 0.186 ± 0.021 min-1) was faster than the HPMC-TiO2 films (kapp = 0.034 ± 0.003 min-1). Then, gelatin-TiO2 dispersion was applied as a coating on the foam nets by dip coating. The gelatin-TiO2 bilayer exhibited higher concentration of ethylene degraded per photocatalytic area and photocatalyst mass unit (13.297 ± 0.178 ppmv m2 [Formula: see text] ) than its film form (18.212 ± 1.157 ppmv m2 [Formula: see text] ), which makes gelatin-TiO2/foam nets a promising composite design for fruit postharvest application.

Bioactive Compounds from Jambolan (Syzygium cumini (L.)) Extract Concentrated by Ultra- and Nanofiltration: a Potential Natural Antioxidant for Food.

Jambolan is an unexplored fruit rich in bioactive compounds like anthocyanins, catechin, and gallic acid. Thus, the extraction of bioactive compounds allows adding value to the fruit. In this context, the present study reports the recovery and concentration of jambolan fruit extract by ultra and nanofiltration for the first time. Acidified water was used to extract polyphenols from the pulp and peel of jambolan. The extracts were concentrated using ultrafiltration and nanofiltration membranes with nominal molecular weight cut-off ranging from 180 to 4000 g mol-1. Total monomeric anthocyanin, total phenolic compounds, and antioxidant capacity were analyzed. Phenolic compounds were quantified, and anthocyanins were identified by high-performance liquid chromatography coupled to diode-array detection and mass spectrometry (HPLC-DAD-MS). Concentration factors higher than 4.0 were obtained for anthocyanins, gallic acid, and catechin after nanofiltration of the extracts. Other compounds such as epicatechin, p-Coumaric acid, and ferulic acid were quantified in the concentrated extract, and the main anthocyanins identified were 3,5-diglucoside: petunidin, malvidin, and delphinidin. Therefore, jambolan extract showed a high potential to be used as a natural dye and antioxidant in food products.

Reactive extrusion-processed native and phosphated starch-based food packaging films governed by the hierarchical structure.

The aim of this research work was to investigate novel tools given by nanotechnology and green chemistry for improving the disadvantages typically associated to the starch-based films: water susceptibility and brittle mechanical behavior. With this in mind, four food packaging film systems were developed from corn starch or corn starch nanocrystals (SNCs), and modified by phosphating under reactive extrusion (REx) conditions using sodium tripolyphosphate (Na5P3O10 - TPP) as a crosslinker. The structural, physicochemical, thermal, rheological and mechanical properties, as well as studies associated with the management of carbohydrate polymer-based plastic wastes (biodegradability and compostability) were carried out in this study. The hierarchical structure and the modification of the starch were dependent on the amylose content and degree of substitution (DS), which in turn depended on the hydrogen (H)-bonding interactions. In both cases, a higher molecular ordering of the starch chains in parallel was decisive to obtain the self-assembled thermoplastic starches. Beyond the valuable results obtained and scientifically analyzed, unfortunately none of the manufactured materials achieved to improve their performance compared to the control film (thermoplastic starch - TPS). It was even thought that the phosphated starch-based films could fertilize lettuce (Lactuca sativa) seedlings during their biodegradation, and this was not achieved either. This possibly due to the low content of phosphorus or its poor bioavailability.

Active coatings based on hydroxypropyl methylcellulose and silver nanoparticles to extend the papaya (Carica papaya L.) shelf life.

This study aimed to understand the effect of silver nanoparticles (AgNPs) on physiochemical properties of hydroxypropyl methylcellulose (HPMC) film-forming solutions (FFS) and nanocomposite films (NCF), as well as the efficacy of these materials to control the development of anthracnose caused by Colletotrichum gloeosporioides in papaya (Carica papaya L.). FFS were characterized by pH, particle size distribution, and rheology. In addition, thickness, morphology, water contact angle, barrier, chemical, crystallinity, thermal, and mechanical properties from NCF were investigated. The minimum inhibitory concentration of AgNPs against C. gloeosporioides was determined by in vitro test. FFS with 0.25 wt% of AgNPs were used as coatings in papayas inoculated with C. gloeosporioides. Finally, the physicochemical parameters were investigated during their storing up to 7 days at 10 °C, followed by 7 days at 20 °C. The presence of AgNPs impacted the thickness, morphology, moisture content, chemical bonds, crystalline structure, and thermal properties of films. Coatings with 0.25 wt% of AgNPs reduced the incidence and severity of C. gloeosporioides and avoided the weight loss of papayas during storing. The ripening of papaya occurred naturally, showing that the coating only delayed this process. Thus, HPMC-AgNPs coating can be an alternative to extend the papaya shelf life.

A novel colorimetric indicator film based on chitosan, polyvinyl alcohol and anthocyanins from jambolan (Syzygium cumini) fruit for monitoring shrimp freshness.

This study aims to develop and characterize colorimetric indicator films based on chitosan, polyvinyl alcohol and anthocyanins from jambolan fruit (Syzygium cumini) prepared by casting method. The effect of anthocyanin extract on thickness, microstructure, moisture content, solubility in water, hydrophobicity, chemical structure, color and opacity of films was analyzed. In addition, anthocyanins photodegradation in films as well its application to monitoring shrimp freshness was studied. Significant effect (p < 0.05) of anthocyanin extract from jambolan fruit on the thickness and optical properties of the films was observed. Anthocyanin extract from jambolan fruit was efficiently incorporated and dispersed into film. The films containing anthocyanins showed visible changes from red color to blue color when used to monitor shrimp freshness at several temperatures (between -20 °C and 20 °C). This research reports for the first time information regarding the valorization and application of anthocyanins from jambolan fruit as an alternative for food packaging sector.

Hydroxypropyl methylcellulose-TiO2 and gelatin-TiO2 nanocomposite films: Physicochemical and structural properties.

Photocatalytic properties of titanium dioxide (TiO2) have been widely studied. However, its tendency to aggregation in biopolymer-based nanocomposites limits its application for food packaging and has been few studied. The aim of this work was to study the dispersion of TiO2 (0-2 wt%) incorporated in the hydroxypropyl methylcellulose (HPMC-TiO2) and gelatin (gelatin-TiO2) film forming solutions. Particle size and zeta potential of TiO2 nanoparticles were investigated. Nanocomposite films were characterized as to the thickness, moisture content, solubility, color, absorption to the light, relative opacity, morphology, chemical composition, crystallinity, thermal and mechanical properties and water vapor permeability (WVP). TiO2 nanoparticles showed better dispersion in acid medium than water. Moisture content, water solubility and WVP of the gelatin-TiO2 films were influenced by the incorporation of TiO2, while HPMC-TiO2 films were not. The increase of relative opacity of the films as TiO2 was more attenuated for the gelatin-TiO2 films due to lower TiO2 aggregation in gelatin. Morphology, chemical composition, crystallinity and thermal properties of the films evidenced that TiO2 was better dispersed in both matrices at 1 wt%. It was also concluded that TiO2 aggregation generated more biphasic regions in HPMC than generated in gelatin, which caused a microstructural reorganization in the matrices.

Self-Assembled Carbohydrate Polymers for Food Applications: A Review.

The self-assembled natural and synthetic polymers are booming. However, natural polymers obtained from native or modified carbohydrate polymers (CPs), such as celluloses, chitosan, glucans, gums, pectins, and starches, have had special attention as raw material in the manufacture of self-assembled polymer composite materials having several forms: films, hydrogels, micelles, and particles. The easy manipulation of the architecture of the CPs, as well as their high availability in nature, low cost, and being sustainable and green polymers have been the main positive points in the use of them for different applications. CPs have been used as building blocks for composite structures, and their easy orientation and ordering has given rise to self-assembled CPs (SCPs). These macromolecules have been little studied for food applications. Nonetheless, their research has grown mainly in the last 5 years as encapsulated food additive wall materials, food coatings, and edible films. The multifaceted properties (systems sensitive to pH, temperature, ionic strength, types of ions, mechanical force, and enzymes) of these devices are leading to the development of advanced food materials. This review article focused on the analysis of SCPs for food applications in order to encourage other research groups for their preparation and implementation.

Microstructure and physical properties of nano-biocomposite films based on cassava starch and laponite.

The aim of this research was to study the effects of laponite concentrations on some properties of nano-biocomposite films based on cassava starch, focusing mainly the relation between the properties of the surface microstructure and roughness, water contact angle and gloss. Nano-biocomposite films were produced by casting. We analyzed gloss, color, opacity, water contact angle, crystallinity by X-ray diffraction, and microstructure by scanning electron microscopy and atomic force microscopy. Texture parameters (energy, entropy and fractal dimension) were extracted from micrographs. We observed a great impact of laponite in the morphology of nano-biocomposite films. Texture parameters correlated with surface heterogeneity and roughness. Finally, surface roughness affected the surface hydrophilicity of nano-biocomposite films. Laponite platelets were exfoliated and/or intercalated with amylose and amylopectin chains. This research reports new information on the effects of laponite concentrations on the morphological, optical and wetting properties of nano-biocomposite films aiming future industrial applications.