Bioactive pectic polysaccharides from bay tree pruning waste: Sequential subcritical water extraction and application in active food packaging

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.

Recent advances in pressurized hot water extraction/modification of polysaccharides: Structure, physicochemical properties, bioactivities, and applications

Pressurized hot water, as a green and efficient physical treatment technology, has been widely utilized for the extraction and modification of polysaccharides, with the objective of enhancing the physicochemical properties and biological activities of polysaccharides applied in food systems. This article reviews the recent advances regarding the effects of pressurized hot water treatment (extraction and modification) on polysaccharide extraction rates, structure, physicochemical properties, and bioactivities. The potential modes and mechanisms of polysaccharides subjected to pressurized hot water treatment and the relevant applications of these treated polysaccharides are also thoroughly discussed. Finally, the challenges that it may encounter in commercial applications are analyzed, and the future trends in this field are envisioned. This article will be of great value for the scientific elucidation of polysaccharides treated with pressurized hot water and their potential food applications.

Genipap Oil as a Natural Cross-Linker for Biodegradable and Low-Ecotoxicity Porous Absorbents via Reactive Extrusion

Proteins derived from agroindustrial coproducts and a natural cross-linking agent (genipap oil containing genipin) were used to develop porous materials by reactive extrusion for replacing fossil-based absorbents. Incorporating genipap oil allowed the production of lightweight structures with high saline uptake (above 1000%) and competing retention capacity despite their porous nature. The mechanical response of the genipap-cross-linked materials was superior to that of the noncross-linked ones and comparable to those cross-linked using commercial genipin. The extruded products were hemocompatible and soil-biodegradable in less than 6 weeks. The compounds generated by the degradation process were not found to be toxic to the soil, showing a high bioassimilation capacity by promoting grass growth. The results demonstrate the potential of biopolymers and new green cross-linkers to produce fully renewable-based superabsorbents in hygiene products with low ecotoxicity. The study further promotes the production of these absorbents using low-cost proteins and continuous processing such as reactive extrusion.

Preservation of freshly-cut lemon slices using alginate-based coating functionalized with antioxidant enzymatically hydrolyzed rice straw-hemicellulose

Food coatings are efficient preservative measures, a crucially needed approach to meet hunger growth as well as food management. In the current study, the construction of an efficient coating using alginate polymer fortified with antioxidant rice straw-hemicellulose hydrolysate was examined. Rice straw hemicellulose fraction was extracted under thermal alkaline conditions with a recovery percentage of 15.8%. The extracted hemicellulose fraction was enzymatically hydrolyzed with microbial xylanase with hydrolysis percentage of 53.8%. Characterization of the produced hydrolysate was performed with the aid of thin layer chromatographic analysis (TLC), high-performance liquid chromatographic analysis (HPLC), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) analysis. The reported data showed that xylobiose (240.68 mg/g) in addition to coumaric (383.33 µg/g) and ferulic acid (298.77 µg/g) as the main constituents of the carbohydrate and the polyphenolic contents, respectively. The hydrolysate possessed antioxidant capacity that significantly increased in a direct correlation with the concentration of the hydrolysate. Finally, the prepared coating solution effectiveness in the preservation of lemon slices against fungal growth was monitored up to 20 days with a significant concentration dependent decrease in weight loss and an increase in its antioxidant activity. The combination of xylooligosaccharide-rich rice straw hydrolysate with alginate-based coating not only improved the storage shelf-life of fresh fruits and vegetables but also provided microbial safety and potential benefits for human health.

Green strategies for the valorization of industrial medicinal residues of Serenoa repens small (saw palmetto) as source of bioactive compounds

Serenoa repens is a medicinal plant well-known for its therapeutic potential in treating various urological disorders and prevention of prostatic cancer. However, the extraction process in the pharmaceutical industry leads to the generation of plant residues, typically discarded, wasting valuable resources. In this study, we aimed to explore a series of green extraction strategies to effectively valorize the residues of Serenoa repens fruits. Initially, we employed supercritical CO2 (1.2% yield on dry biomass) on the discarded biomass to identify and quantify residual fatty acids and polyprenols (1.6% of the extract dry weight), a class of unsaturated isoprenoid alcohols with promising biomedical applications. Subsequently, subcritical water extraction was utilized on the exhausted biomass to extract polar compounds. An increase in the extraction yield was observed with the rise in processing temperature up to 180 °C (yields were found higher than 26%). Phenolic compounds and carbohydrate macromolecules profiles were affected by the increased hydrolytic conditions. Polar extracts exhibited robust bioactivities, demonstrating significant antioxidant activity and antimicrobial efficacy against Gram-positive and Gram-negative bacteria strains. Extracts obtained at 180 °C demonstrated the highest efficacy. Furthermore, in vitro assessment of mannans-rich fraction provided a new perspective of potential applications in the cosmeceuticals field. Results underscore the potential of the sustainable extraction biorefinery for the residue of this medicinal plant and demonstrate that, harnessing these bioactive compounds, new sustainable and eco-friendly approaches for its complete utilization can be offered, thereby promoting near-zero waste practices and contributing to a more sustainable future.

Preparation and characterization of biodegradable food packaging films using lemon peel pectin and chitosan incorporated with neem leaf extract and its application on apricot fruit

The present study aims to develop and characterize biodegradable packaging films from lemon peel-derived pectin and chitosan incorporated with a bioactive extract from neem leaves. The films (PCNE) contained varying concentrations of neem leaf extract and were comprehensively assessed for their physical, optical, mechanical, and antimicrobial attributes. The thickness, moisture content, water solubility, and water vapor permeability of the biodegradable packaging films increased with the increasing concentration of neem leaf extract. Comparatively, the tensile strength of the films decreased by 42.05 % compared to the control film. The Scanning Electron Microscopy (SEM) confirmed that the resultant blended pectin-chitosan films showed a uniform structure without cracks. Furthermore, the analysis targeting Staphylococcus aureus and Aspergillus niger indicated that the films had potent antimicrobial activity. Based on these results, the optimum films were selected and subsequently applied on apricot fruits to increase their shelf life at ambient temperature. The findings, after examining factors such as colour, firmness, total soluble solids, shrinkage, weight loss, and appearance, concluded that the apricots coated by PCNE-5 had the most delayed signs of spoilage and increased their shelf life by 50 %. The results showed the potential applicability of lemon peel pectin-chitosan-neem leaf extract blend films in biodegradable food packaging.

Subcritical water extraction of Equisetum arvense biomass withdraws cell wall fractions that trigger plant immune responses and disease resistance

Plant cell walls are complex structures mainly made up of carbohydrate and phenolic polymers. In addition to their structural roles, cell walls function as external barriers against pathogens and are also reservoirs of glycan structures that can be perceived by plant receptors, activating Pattern-Triggered Immunity (PTI). Since these PTI-active glycans are usually released upon plant cell wall degradation, they are classified as Damage Associated Molecular Patterns (DAMPs). Identification of DAMPs imply their extraction from plant cell walls by using multistep methodologies and hazardous chemicals. Subcritical water extraction (SWE) has been shown to be an environmentally sustainable alternative and a simplified methodology for the generation of glycan-enriched fractions from different cell wall sources, since it only involves the use of water. Starting from Equisetum arvense cell walls, we have explored two different SWE sequential extractions (isothermal at 160 ºC and using a ramp of temperature from 100 to 160 ºC) to obtain glycans-enriched fractions, and we have compared them with those generated with a standard chemical-based wall extraction. We obtained SWE fractions enriched in pectins that triggered PTI hallmarks in Arabidopsis thaliana such as calcium influxes, reactive oxygen species production, phosphorylation of mitogen activated protein kinases and overexpression of immune-related genes. Notably, application of selected SWE fractions to pepper plants enhanced their disease resistance against the fungal pathogen Sclerotinia sclerotiorum. These data support the potential of SWE technology in extracting PTI-active fractions from plant cell wall biomass containing DAMPs and the use of SWE fractions in sustainable crop production.

Development of antioxidant and smart NH3 -sensing packaging film by incorporating bilirubin into κ-carrageenan matrix

BACKGROUND

Active and smart food packaging based on natural polymers and pH-sensitive dyes as indicators has attracted widespread attention. In the present study, an antioxidant and amine-response color indicator film was developed by incorporating bilirubin (BIL) into the κ-carrageenan (Carr) matrix.

RESULTS

It was found that the introduction of BIL had no effect on the crystal/chemical structure, water sensitivity and mechanical performance of the Carr-based films. However, the barrier properties to light and the thermal stability were significantly improved after the addition BIL. The Carr/BIL composite films exhibited excellent 1,1-diphenyl-2-picryl-hydrazyl (i.e. DPPH)/2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (i.e. ABTS) free radical scavenging abilities and color responsiveness to different concentrations of ammonia. The application assay reflected that the Carr/BIL0.0075 film was effective in delaying the oxidative deterioration of shrimp during storage and realizing the color response of its freshness through the change of b* value.

CONCLUSION

Active and smart packaging films were successfully prepared by incorporating different contents of BIL into the Carr matrix. The present study helps to further encourage the design and development of a multi-functional packaging material. © 2023 Society of Chemical Industry.

Boosting functional properties of active-CMC films reinforced with agricultural residues-derived cellulose nanofibres

The search for packaging alternatives that reduce the presence of non-biodegradable plastics in water is a focus of much research today. This fact, together with the increasing demand for active packaging capable of prolonging the shelf life of foodstuffs and the rise in the use of natural biopolymers such as cellulose, motivate the present work. This work evaluates CMC films loaded with gallic acid reinforced with (ligno)cellulose nanofibres from various agricultural residues as candidates for use in active food packaging. The first stage of the study involved the evaluation of different nanofibres as the reinforcing agent in CMC films. Increasing proportions of nanofibres (1, 3, 5 and 10% w/w) from horticultural residues (H) and nanofibres from vine shoots (V), containing residual lignin (LCNF) and without it (CNF), and obtained by mechanical (M) or chemical (T) pretreatment, were studied. The results of this first stage showed that the optimum reinforcement effect was obtained with 3% H-MCNF or 3% V-MCNF, where up to 391% and 286% improvement in tensile strength was achieved, respectively. These films offered slightly improved UV-light blocking ability (40-55% UV-barrier) and water vapor permeability (20-30% improvement) over CMC. Next, bioactive films were prepared by incorporating 5 and 10% wt of gallic acid (GA) over the optimised formulations. It was found that the joint addition of cellulose nanofibres and GA enhanced all functional properties of the films. Mechanical properties improved to 70%, WVP to 50% and UV light blocking ability to 70% due to the synergistic effect of nanofibres and GA. Finally, the bioactive films exhibited potent antioxidant activity, 60-70% in the DPPH assay and >99% in the ABTS assay and high antimicrobial capacity against S. aureus.

Pectin grafted with resorcinol and 4-hexylresorcinol: Preparation, characterization and application in meat preservation

To augment the functional attributes of pectin and expand its prospective utilization in food preservation, this research explored the enzymatic grafting of resorcinol and 4-hexylresorcinol onto pectin. Structural analysis verified the successful grafting of both resorcinol and 4-hexylresorcinol to pectin via esterification, with the 1-OH of resorcinol and 4-hexylresorcinol and the carboxyl group of pectin functioning as grafting sites. The grafting ratios of resorcinol-modified pectin (Re-Pe) and 4-hexylresorcinol-modified pectin (He-Pe) were 17.84 % and 10.98 %, respectively. This grafting modification notably enhanced the antioxidative and antibacterial properties of pectin. Specifically, DPPH clearance and the inhibition ratio in the β-carotene bleaching assay increased from 11.38 % and 20.13 % (native pectin, Na-Pe) to 41.15 % and 36.67 % (Re-Pe), and 74.72 % and 53.40 % (He-Pe). Moreover, the inhibition zone diameter against Escherichia coli and Staphylococcus aureus rose from 10.12 and 10.08 mm (Na-Pe) to 12.36 and 11.52 mm (Re-Pe), and 16.78 and 14.87 mm (He-Pe). Additionally, the application of native and modified pectin coatings effectively impeded pork spoilage, with the modified pectins demonstrating a more potent effect. Among the two modified pectins, He-Pe exhibited the most significant enhancement in pork shelf life.

Chitosan Based Materials in Cosmetic Applications: A Review

This review provides a report on the properties and recent advances in the application of chitosan and chitosan-based materials in cosmetics. Chitosan is a polysaccharide that can be obtained from chitin via the deacetylation process. Chitin most commonly is extracted from cell walls in fungi and the exoskeletons of arthropods, such as crustaceans and insects. Chitosan has attracted significant academic interest, as well as the attention of the cosmetic industry, due to its interesting properties, which include being a natural humectant and moisturizer for the skin and a rheology modifier. This review paper covers the structure of chitosan, the sources of chitosan used in the cosmetic industry, and the role played by this polysaccharide in cosmetics. Future aspects regarding applications of chitosan-based materials in cosmetics are also mentioned.

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).

Renovation of Agro-Waste for Sustainable Food Packaging: A Review

Waste management in the agricultural sector has become a major concern. Increased food production to satisfy the surge in population has resulted in the generation of large volumes of solid waste. Agro-waste is a rich source of biocompounds with high potential as a raw material for food packaging. Utilization of agro-waste supports the goal of sustainable development in a circular economy. This paper reviews recent trends and the development of agro-wastes from plant and animal sources into eco-friendly food packaging systems. Different plant and animal sources and their potential development into packaging are discussed, including crop residues, process residues, vegetable and fruit wastes, and animal-derived wastes. A comprehensive analysis of the properties and production methods of these packages is presented. Future aspects of agro-waste packaging systems and the inherent production problems are addressed.

Structural Characteristics of Rehmannia glutinosa Polysaccharides Treated Using Different Decolorization Processes and Their Antioxidant Effects in Intestinal Epithelial Cells

Polysaccharide decolorization is a key determinant of polysaccharide structure. In this study, two purified Rehmannia glutinosa polysaccharides, RGP−1−A and RGP−2−A, were obtained after decolorization using the AB-8 macroporous resin and H₂O₂, respectively. RGP−1−A (molecular weight (Mw) = 18,964 Da) and RGP−2−A (Mw = 3305 Da) were acidic and neutral heteropolysaccharides, respectively, and were both polycrystalline in structure. FTIR analysis revealed that RGP−1−A was a sulfate polysaccharide, while RGP−2−A had no sulfate group. Experiments on IPEC-1 cells showed that RGPs alleviated oxidative stress by regulating the Nrf2/Keap1 pathway. These findings were confirmed by the upregulation of Nrf2, NQO1, and HO-1; the subsequent increase in the levels of antioxidant indicators (SOD, LDH, CAT, and MDA); and the restoration of mitochondrial membrane potential. Overall, the antioxidant capacity of RGP−1−A was significantly higher than that of RGP−2−A. These results suggest that RGPs may be a potential natural antioxidant and could be developed into functional foods.

Characterizations and antibacterial activities of passion fruit peel pectin/chitosan composite films incorporated Piper betle L. leaf extract for preservation of purple eggplants

The present study aimed to synthesize biodegradable films based on crosslinked passion fruit peel pectin/chitosan (P/CH) films incorporated with a bioactive extract from Piper betle L. leaf, and investigate their morphological, mechanical, water vapor permeability, optical, and antibacterial properties. The thickness and water vapor permeability of P/CH blend films were proportional to the increasing concentration of Piper betle extract (PB). The tensile strength of P/CH/PB films was significantly reduced at 42.89% compared to the P/CH films. The morphological characterization affirmed that resultant blend films showed a well-organized homogeneous structure with no cracks. Moreover, the antibacterial activities against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus cereus, and Klebsiella pneumoniae increased with the increased concentration of PB in the obtained films. Our results demonstrated that P/CH/PB blend films could be potentially used for food packaging applications.

Recent advances in utilization of pectins in biomedical applications: a review focusing on molecular structure-directing health-promoting properties

The numerous health benefits of pectins justify their inclusion in human diets and biomedical products. This review provides an overview of pectin extraction and modification methods, their physico-chemical characteristics, health-promoting properties, and pharmaceutical/biomedical applications. Pectins, as readily available and versatile biomolecules, can be tailored to possess specific functionalities for food, pharmaceutical and biomedical applications, through judicious selection of appropriate extraction and modification technologies/processes based on green chemistry principles. Pectin's structural and physicochemical characteristics dictate their effects on digestion and bioavailability of nutrients, as well as health-promoting properties including anticancer, immunomodulatory, anti-inflammatory, intestinal microflora-regulating, immune barrier-strengthening, hypercholesterolemia-/arteriosclerosis-preventing, anti-diabetic, anti-obesity, antitussive, analgesic, anticoagulant, and wound healing effects. HG, RG-I, RG-II, molecular weight, side chain pattern, and degrees of methylation, acetylation, amidation and branching are critical structural elements responsible for optimizing these health benefits. The physicochemical characteristics, health functionalities, biocompatibility and biodegradability of pectins enable the construction of pectin-based composites with distinct properties for targeted applications in bioactive/drug delivery, edible films/coatings, nano-/micro-encapsulation, wound dressings and biological tissue engineering. Achieving beneficial synergies among the green extraction and modification processes during pectin production, and between pectin and other composite components in biomedical products, should be key foci for future research.