Characterization of aerogels as bioactive delivery vehicles produced through the valorization of yerba-mate (Illex paraguariensis)

Cellulose-based delivery systems for bioactive ingredients: A review

Considering the outstanding advantages including abundant resources, structure-performance designability, impressive mechanical strength, and 3D network structure-forming ability, cellulose is an ideal material for encapsulating bioactive ingredients. Due to its low solubility in water, large-scaled morphology and poor flexibility, cellulose is unsuitable for the construction of carriers. Consequently, the majority of cellulose is employed following physical or chemical modification. Cellulose and its derivatives are extensively employed in the food industry, including fat replacement, food packaging composites, food additives, 3D-printed food and delivery systems. Their benefits in food delivery systems are particularly pronounced. Therefore, the distinguishing features, preparation methods, recent developments and effectiveness of different cellulose-based delivery systems for bioactive ingredients are discussed. Cellulose-based delivery systems offer unique advantages in terms of environmental impact reduction, modification facilitation, stimuli-responsive release as well as tailored design, and their application has gained widespread recognition. However, they are facing challenges in the application process comprising modification methods for cellulose-based materials, new methods for commercial preparation on a wide scale, cellulose-based multifunctional conveyance systems and systematic evaluation using in vivo experiments. In conclusion, this review provides theoretical references for the development of novel delivery carriers as well as the efficient application and popularization of cellulose-based delivery systems.

Bioactive aerogels based on native and phosphorylated potato (Solanum tuberosum L.) starches incorporated with star fruit extract (Averrhoa carambola L.)

The aim of this study was to develop a star fruit extract (SFE) and incorporate it into aerogels based on native and phosphorylated potato starches. The phosphorylation of starch enhances its properties by incorporating phosphate groups that increase the spaces between starch molecules, resulting in a more resilient, intact aerogel with enhanced water absorption. The bioactive aerogels based on potato starch and 10, 15, and 20 % (w/w) of SFE were characterized by their morphological and thermogravimetric properties, infrared spectra, water absorption capacity, loading capacity, and antioxidant activity. Epicatechin was the major compound present in SFE. The thermal stability of SFE increased when incorporated into phosphorylated starch aerogels at a concentration of 20 %. The water absorption capacity was higher in phosphorylated starch aerogels (reaching 1577 %) than in their native counterparts (reaching 1100 %). Native starch aerogels with 15 and 20 % SFE exhibited higher antioxidant activity against hydroxyl free radicals compared to phosphorylated starch aerogels, achieving 79.9 % and 86.4 % inhibition for the hydroxyl and nitric oxide radicals, respectively. The ideal choice of freeze-dried aerogel depends on the desired effect, either to act as an antioxidant agent by releasing bioactive compounds from SFE or as a water-absorbent agent in food products.

Absorbent bioactive aerogels based on germinated wheat starch and grape skin extract

This study aimed to produce water-absorbent bioactive aerogels using biodegradable raw materials, wheat starch and poly ethylene oxide (PEO), and derived from agro-industrial residues (grape skin) obtained in the wine industry. The aerogels were produced using germinated wheat starch (GWS), with and without PEO, and incorporating grape skin extract (GSE) at concentrations of 5 and 10 % (w/w). The GSE was evaluated for total and individual phenolic compounds, anthocyanins, and antioxidant activity. The starch aerogels were characterized for morphology, density, porosity, functional groups by FT-IR, relative crystallinity and diffraction pattern, water absorption capacity, antioxidant activity, and in vitro release profile of phenolic compounds in food simulant medium. The total phenolic compounds in GSE was 226.25 ± 0.01 mg equivalent of gallic acid/g GSE. The aerogels showed low density and high porosity. All aerogels demonstrated high water absorption capacity (581.4 to 997.5 %). The antioxidant activity of the aerogels increased with increasing GSE concentration and the addition of PEO. The aerogels could release GSE gradually for up to 120 days in the hydrophilic simulant medium and 240 h for the hydrophobic medium. Starch-based aerogels with GSE showed potential to be applied as exudate absorbers with antioxidant activity to develop active food packaging.

Cellulose/Salep-based intelligent aerogel with red grape anthocyanins: Preparation, characterization and application in beef packaging

The purpose of this study was to prepare a porous intelligent aerogel for food packaging applications, in particular for monitoring minced beef freshness, using cellulose extracted from grape stalk, Salep as a copolymer, and red grape anthocyanins as a pH-sensitive pigment. Aerogels based on cellulose 1% (w/v) and Salep 1% (w/v) at ratios of 1:3, 3:1, and 1:1 were prepared by lyophilization. Aerogel with high porosity, low density, and higher mean pore size was chosen for preparing intelligent colorimetric aerogel (ICA) with the addition of 0.44 mg/100 mL of anthocyanins. Based on the color parameters, the stability of ICA was satisfactory when exposed to both light and dark conditions, as well as when stored at either 4 or 25 °C. Additionally, X-ray diffraction and thermogravimetric analyses indicated that an amorphous aerogel was formed, with a thermal decomposition temperature of 320 °C. The color of the ICA changed from purple on the first and 3rd days of packaging to blue-gray on the 6th day. As the spoilage process continued, the color of the indicator became dark brown. Taken together, ICA showed a quick response to minced beef spoilage with the ability to differentiate between fresh and spoiled meat during storage at 4 °C.

Development of highly reusable, mechanically stablecorn starch-based aerogel using glycerol for potential application in the storage of fresh spinach leaves

Impact of glycerol on the physico-functional, morphological, mechanical, and rehydration properties ofcorn starch-based aerogel has been investigated. The aerogel was prepared from hydrogel (sol-gel method) using solvent exchange and supercritical CO₂ drying. Glycerol-infused aerogel had a more connected, denser structure (0.38-0.45 g/cm³), enhanced hygroscopic behavior, and was reusable up to eight times in terms of its capacity to absorb water after being drawn from the soaked sample. However, the inclusion of glycerol reduced the aerogel's porosity (75.89-69.91 %) and water absorption rate (WAR; 118.53-84.64 %) but enhanced its percentage shrinkage (75.03-77.99 %) and compressive strength (26.01-295.06 N). The most effective models for describing the rehydration behavior of aerogel were determined to be the Page, Weibull, and Modified Peleg models. Glycerol addition improved the internal strength of the aerogel so could be recycled without significant change in the physical characteristics of the aerogel. By effectively eliminating the condensed moisture that was developed inside the packing owing to the transpiration of fresh spinach leaves, the aerogel extended the storage life of the leaves by up to eight days. The glycerol-based aerogel has the potential to be employed as a carrier matrix for various chemicals and a moisture scavenger.

Emerging Trends in Nanotechnology: Aerogel-Based Materials for Biomedical Applications

At present, aerogel is one of the most interesting materials globally. The network of aerogel consists of pores with nanometer widths, which leads to a variety of functional properties and broad applications. Aerogel is categorized as inorganic, organic, carbon, and biopolymers, and can be modified by the addition of advanced materials and nanofillers. Herein, this review critically discusses the basic preparation of aerogel from the sol-gel reaction with derivation and modification of a standard method to produce various aerogels for diverse functionalities. In addition, the biocompatibility of various types of aerogels were elaborated. Then, biomedical applications of aerogel were focused on this review as a drug delivery carrier, wound healing agent, antioxidant, anti-toxicity, bone regenerative, cartilage tissue activities and in dental fields. The clinical status of aerogel in the biomedical sector is shown to be similarly far from adequate. Moreover, due to their remarkable properties, aerogels are found to be preferably used as tissue scaffolds and drug delivery systems. The advanced studies in areas including self-healing, additive manufacturing (AM) technology, toxicity, and fluorescent-based aerogel are crucially important and are further addressed.

Bioactive Absorbent Chitosan Aerogels Reinforced with Bay Tree Pruning Waste Nanocellulose with Antioxidant Properties for Burger Meat Preservation

As a transition strategy towards sustainability, food packaging plays a crucial role in the current era. This, carried out in a biorefinery context of agricultural residues, involves not only obtaining desirable products but a comprehensive utilization of biomass that contributes to the circular bioeconomy. The present work proposes the preparation of bioactive absorbent food pads through a multi-product biorefinery approach from bay tree pruning waste (BTPW). In a first step, chitosan aerogels reinforced with lignocellulose and cellulose micro/nanofibers from BTPW were prepared, studying the effect of residual lignin on the material's properties. The presence of micro/nanofibers improved the mechanical performance (up to 60%) in addition to increasing the water uptake (42%) when lignin was present. The second step was to make them bioactive by incorporating bay leaf extract. The residual lignin in the micro/nanofibers was decisive, since when present, the release profiles of the extract were faster, reaching an antioxidant power of more than 85% after only 30 min. Finally, these bioactive aerogels were used as absorbent pads for fresh meat. With the use of the bioactive aerogels (with ≥2% extract), the meat remained fresh for 10 days as a result of delayed oxidation of the food during storage (20% metmyoglobin proportion).

Polysaccharide-based porous biopolymers for enhanced bioaccessibility and bioavailability of bioactive food compounds: Challenges, advances, and opportunities

Bioactive food compounds, such as lycopene, curcumin, phytosterols, and resveratrol, have received great attention due to their potential health benefits. However, these bioactive compounds (BCs) have poor chemical stability during processing and low bioavailability after consumption. Several delivery systems have been proposed for enhancing their stability and bioavailability. Among these methods, porous biopolymers have emerged as alternative encapsulation materials, as they have superior properties like high surface area, porosity, and tunable surface chemistry to entrap BCs. This reduces the crystallinity (especially for the lipophilic ones) and particle size, and in turn, increases solubilization and bioavailability. Also, loading BCs into the porous matrix can protect them against environmental stresses such as light, heat, oxygen, and pH. This review introduces polysaccharide-based porous biopolymers for improving the bioaccessibility/bioavailability of bioactive food compounds and discusses their recent applications in the food industry. First, bioaccessibility and bioavailability are described with a special emphasis on the factors affecting them. Then, porous biopolymer fabrication methods, including supercritical carbon dioxide (SC-CO₂ ) drying, freeze-drying, and electrospinning and electrospraying, are thoroughly discussed. Finally, common polysaccharide-based biopolymers (i.e., starch, nanocellulose, alginate, and pectin) used for generating porous materials are reviewed, and their current and potential future food applications are critically discussed.

Extraction and determination of the Pimelea toxin simplexin in complex plant-polymer biocomposites using ultrahigh-performance liquid chromatography coupled with quadrupole Orbitrap mass spectrometry

In the present paper, we describe how a robust and fundamental methodology was developed for extraction and determination of a principal natural toxin compound, simplexin, from a series of bulk biocomposites. These complex matrices were fabricated by direct encapsulating either ground plant particles or an ethanolic crude extract of the Australian toxic pasture plant Pimelea trichostachya in the biodegradable polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Proton nuclear magnetic resonance spectroscopy was initially employed to examine the chemical compositions of these complicated systems. Then, a more sensitive strategy was developed and validated by combining solid-phase extraction and ultrahigh-performance liquid chromatography hyphenated with a quadrupole Orbitrap mass spectrometer for the quantification of simplexin embedded in different biocomposites. Satisfactory linearity (R² > 0.99) and recovery ranges (86.8-116%) with precision (relative standard deviations) of between 0.2 and 13% (n = 3) were achieved from seven biocomposites. The established protocol was further shown to be accurate and reliable in confirming the homogeneous distribution of the simplexin in different biocomposite formulations. A limited mass transfer of simplexin (< 3.5%) from one of the biocomposites into a simulated but sterilized in vitro rumen environment after a 10-day incubation was also revealed by utilizing the method. This quantitative analysis of targeted natural product within plant material-integrated polymeric platforms has potential application when controlled release is required in the bovine rumen and other biological systems. Graphical abstract.

Aerogels based on corn starch as carriers for pinhão coat extract (Araucaria angustifolia) rich in phenolic compounds for active packaging

The objective of this study was to produce renewable aerogels from native and anionic corn starches loaded with pinhão coat extract (PCE) with water absorbent capacity, antioxidant activity and controlled release of phenolic compounds in a hydrophilic food simulant media. Starch aerogels were produced with different concentrations of PCE, 5 and 10%, and evaluated for FT-IR spectra, relative crystallinity, thermal properties, water absorption capacity (WAC), density, antioxidant activity and in vitro release. Thermal stability of the compounds was improved by the incorporation of PCE. The aerogels presented high WAC of 541 to 731% and low-density values of 0.03 g.cm^-1. The highest inhibition of DPPH and ABTS radicals was presented to anionic starch aerogels with 10% PCE rendering 26% of inhibition of ABTS and 24% of DPPH. The maximum in vitro releases for native and anionic starch aerogels with 5% of PCE were 28.70 and 29.44%, respectively, and for aerogels with 10% of PCE they were 34.27 and 35.94%, respectively. The anionic starch aerogels had the highest amount of phenolic compounds released when compared to the native starch aerogels. The starch-based bioactive aerogels showed potential to be applied in food packaging as water absorbent and as a carrier of phenolic compounds.

Yerba Mate Extract in Microfibrillated Cellulose and Corn Starch Films as a Potential Wound Healing Bandage

Microfibrillated cellulose films have been gathering considerable attention due to their high mechanical properties and cheap cost. Additionally, it is possible to include compounds within the fibrillated structure in order to confer desirable properties. Ilex paraguariensis A. St.-Hil, yerba mate leaf extract has been reported to possess a high quantity of caffeoylquinic acids that may be beneficial for other applications instead of its conventional use as a hot beverage. Therefore, we investigate the effect of blending yerba mate extract during and after defibrillation of Eucalyptus sp. bleached kraft paper by ultrafine grinding. Blending the extract during defibrillation increased the mechanical and thermal properties, besides being able to use the whole extract. Afterwards, this material was also investigated with high content loadings of starch and glycerine. The results present that yerba mate extract increases film resistance, and the defibrillated cellulose is able to protect the bioactive compounds from the extract. Additionally, the films present antibacterial activity against two known pathogens S. aureus and E. coli, with high antioxidant activity and increased cell proliferation. This was attributed to the bioactive compounds that presented faster in vitro wound healing, suggesting that microfibrillated cellulose (MFC) films containing extract of yerba mate can be a potential alternative as wound healing bandages.

Comparative Study of the Structural Properties, Color, Bioactive Compounds Content and Antioxidant Capacity of Aerated Gelatin Gels Enriched with Cryoconcentrated Blueberry Juice during Storage

Cryoconcentrated blueberry juice (CBJ) was incorporated into aerated gelatin gel and the effects on the mechanical properties, phenolic compounds and antioxidant activity (AA) were evaluated at day 1 and day 28 under refrigerated storage. At day 1, 8 g of gelatin gel and 40 g of CBJ (called M5) exhibited a soft texture and heterogeneous and non-spherical small bubbles, with values close to 10.5, 8.0 and 7.1 N, for hardness, gumminess and chewiness, respectively. M5 presented an increase of approximately 1.7, 1.9 and 1.9, and 1.2, 1.8, 2.1 and 1.3 times in comparison to the other samples, for total polyphenol, anthocyanin and flavonoid contents, and individual phenolic compounds, 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) assays, respectively. At day 28, the samples showed a weakening of the 3D network, with high degradation of phenolic compounds and AA due to the oxidation, polymerization and syneresis. Therefore, CBJ might be an interesting functional ingredient to add to (aerated and non-aerated) gelatin gel without affecting its properties, and thus different food products with high nutritional values and without added artificial sweeteners could be developed. Additionally, the gelatin gel/CBJ combinations might be suitable for additive manufacturing as a coating of food matrices.