Advances in Food Waste Biomass Transformation into High-Value Products

In recent years, there has been a concerning surge in waste generation, with agri-food waste emerging as a significant issue across various stages of the food supply chain [...].

Formulation of Antioxidant Gummies Based on Gelatin Enriched with Citrus Fruit Peels Extract

In this work, the peels of red and blonde oranges as well as lemons were efficiently (5.75-9.65% yield) extracted by hydroalcoholic solution with ultrasound assistance and employed as active molecule sources in the preparation of functional gummies. Antioxidant performances of the hydroalcoholic extracts were characterized by colorimetric assays, whereas LC-HRMS analyses identified the main bioactive compounds (phenolic acids and flavonoids). The highest scavenging activity was recorded for lemon extract in an aqueous environment (IC50 = 0.081 mg mL-1). An ecofriendly grafting procedure was performed to anchor polyphenols to gelatin chains, providing macromolecular systems characterized by thermal analysis and antioxidant properties. Scavenger abilities (IC50 = 0.201-0.454 mg mL-1) allowed the employment of the conjugates as functional ingredients in the preparation of gummies with remarkable antioxidant and rheological properties over time (14 days). These findings confirmed the possible employment of highly polluting wastes as valuable sources of bioactive compounds for functional gummies preparation.

Synthesis and Characterization of a Biopolymer Pectin/Ethanolic Extract from Olive Mill Wastewater: In Vitro Safety and Efficacy Tests on Skin Wound Healing

Wound-healing delay is one of the major problems of type 2 diabetes, representing also a clinical emergency in non-healing chronic wounds. Natural antioxidants show interesting wound-healing properties, including those extracted from waste derived from olive oil production. Olive mill wastewater is one of the main by-products of the olive oil-making process, and it is rich in high-value secondary metabolites, mainly hydroxytyrosol. We proposed an eco-friendly extraction method, employing both ultrasound-assisted and Soxhlet techniques and ethanol as a solvent, to recover valuable molecules from Roggianella cv (Olea europea L.) olive mill wastewater, which was further entrapped in a pectin polymer via an enzymatic reaction using porcine pancreatic lipase. Pectin, in combination with other substances, promoted and accelerated wound healing and demonstrated good potential to produce a biomedical conjugate for wound treatment. The antioxidant activity of the extracts and conjugate were evaluated against lipophilic (IC50 equal to 0.152 mg mL-1) and hydrophilic (IC50 equal to 0.0371 mg mL-1) radical species as well as the in vitro cytotoxicity via NRU, h-CLAT, and a wound-healing scratch assay and assessment. The pectin conjugate did not exert hemolytic effects on the peripheral blood, demonstrating interesting wound-healing properties due to its ability to stimulate cell proliferation in a dose-dependent manner.

Wine Lees as Source of Antioxidant Molecules: Green Extraction Procedure and Biological Activity

An ultrasound-assisted extraction method, employing ethanol and water as solvents at low temperature (30 °C) and reduced time (15 min), was proposed to extract bioactive molecules from different cultivars (Magliocco Canino, Magliocco Rosato, Gaglioppo, and Nocera Rosso) of wine lees. All the extract yields were evaluated and their contents of phenolic acids, flavonoids, and total polyphenols were determined by means of colorimetric assays and high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD) and Fourier transform infrared (FTIR) techniques. Radical scavenging assays were performed and the Magliocco Canino extracted with a hydroalcoholic mixture returned the best results both against ABTS (0.451 mg mL−1) and DPPH (0.395 mg mL−1) radicals. The chemometric algorithms principal component analysis (PCA) and partial least square regression (PLS) were used to process the data obtained from all qualitative–quantitative sample determinations with the aim of highlighting data patterns and finding possible correlations between composition and antioxidant features of the different wine lees cultivars and the extraction procedures. Wine lees from Magliocco Canino and Magliocco Rosato were found to be the best vegetable matrices in terms of metabolite content and antioxidant properties. The components extracted with alcoholic or hydroalcoholic solvents, specifically (−)-epigallocatechin gallate, chlorogenic acid, and trans-caftaric acid, were found to be correlated with the antioxidant capacity of the extracts. Multivariate data processing was able to identify the compounds related to the antioxidant features. Two PLS models were optimized by using their concentration levels to predict the IC50 values of the extracts in terms of DPPH and ABTS with high values of correlation coefficient R2, 0.932 and 0.824, respectively, and a prediction error lower than 0.07. Finally, cellular (SH-SY5Y cells) antioxidant assays were performed on the best extract (the hydroalcoholic extract of Magliocco Canino cv) to confirm its biological performance against radical species. All these recorded data strongly outline the aptness of valorizing wine lees as a valuable source of antioxidants.

A Tara Gum/Olive Mill Wastewaters Phytochemicals Conjugate as a New Ingredient for the Formulation of an Antioxidant-Enriched Pudding

Olive mill wastewater, a high polyphenols agro-food by-product, was successfully exploited in an eco-friendly radical process to synthesize an antioxidant macromolecule, usefully engaged as a functional ingredient to prepare functional puddings. The chemical composition of lyophilized olive mill wastewaters (LOMW) was investigated by HPLC-MS/MS and ¹H-NMR analyses, while antioxidant profile was in vitro evaluated by colorimetric assays. Oleuropein aglycone (5.8 μg mL^-1) appeared as the main compound, although relevant amounts of an isomer of the 3-hydroxytyrosol glucoside (4.3 μg mL^-1) and quinic acid (4.1 μg mL^-1) were also detected. LOMW was able to greatly inhibit ABTS radical (IC₅₀ equal to 0.019 mg mL^-1), displaying, in the aqueous medium, an increase in its scavenger properties by almost one order of magnitude compared to the organic one. LOMW reactive species and tara gum chains were involved in an eco-friendly grafting reaction to synthesize a polymeric conjugate that was characterized by spectroscopic, calorimetric and toxicity studies. In vitro acute oral toxicity was tested against 3T3 fibroblasts and Caco-2 cells, confirming that the polymers do not have any effect on cell viability at the dietary use concentrations. Antioxidant properties of the polymeric conjugate were also evaluated, suggesting its employment as a thickening agent, in the preparation of pear puree-based pudding. High performance of consistency and relevant antioxidants features over time (28 days) were detected in the milk-based foodstuff, in comparison with its non-functional counterparts, confirming LOWM as an attractive source to achieve high performing functional foods.

Formulation of New Baking (+)-Catechin Based Leavening Agents: Effects on Rheology, Sensory and Antioxidant Features during Muffin Preparation

The aim of this investigation was to prepare two solid mixtures containing a soluble polymorph of (+)-catechin and mucic (MUC) or tartaric (TAR) acids as new leavening agents. The solid mixtures were based on a polymorph of (+)-catechin, characterized through Powder X-ray Diffraction (PXRD) analysis and assayed in in vitro antioxidant and solubility assays. The dough samples were studied by dynamic rheological tests, while muffins were studied through Headspace Solid-Phase Microextraction (HS-SPME)/ Gas Chromatography-Mass Spectrometry (GC-MS) analysis to identify volatile compounds, in vitro tests to evaluate antioxidant properties, and sensory analyses. TAR powder showed a solubility in water almost one order of magnitude increased with respect to commercial (+)-catechin (40.0 against 4.6 mg mL-1) and increased antioxidant performances. In particular, TAR showed total phenolic content (TPC) and total antioxidant capacity (TAC) values of 0.0298 ± 0.021 and 0.0081 ± 0.0009 meq CT/g, while MUC showed better results in terms of 2,2-diphenyl-1-picrylhydrazyl) acid (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 0.518 ± 0.015 and 0.112 ± 0.010mg/mL, respectively. MS analysis identified different compounds derived from the lipid oxidation process. Muffins obtained using both powders showed interesting outcomes regarding dough process and appreciable appearance/olfactory/taste/texture profiles. Muffins obtained from TAR-based mixture showed also a total phenolic content of 0.00175 meq CT/g muffin, and almost two times improved TAC and scavenger activity against DPPH radical. The formulated powders could be used as suitable health-promoting ingredients in the food industry.

Vasorelaxant Effects Induced by Red Wine and Pomace Extracts of Magliocco Dolce cv

Several epidemiological studies demonstrate that moderate (red) wine consumption may afford protection against cardiovascular diseases. Protection is ascribed to the biological activity of wine components, many of which, however, are discarded during winemaking. In vitro rat thoracic aorta rings contracted with phenylephrine or KCl were used to assess the vasorelaxant activity of extracts from wine pomaces (seeds and skins) of the Calabrian autochthonous grape variety Magliocco dolce (Arvino). NMR spectroscopy was used to ascertain their chemical composition. Data demonstrate that seed and skin, but not must, extracts are capable of relaxing vascular preparations in an endothelium-dependent manner, similarly to the red wine extract, due to the presence of comparable amounts of bioactive constituents. In rings pre-contracted with 20–30 mM KCl, only seed extracts showed a moderate relaxation. The most efficacious vasodilating extract (wine) showed a good antioxidant profile in both [(2,2-diphenyl-1-picrylhydrazyl)acid] radical (DPPH) and [2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid)] radical (ABTS) assays. In conclusion, winemaking from Magliocco dolce grape can provide potentially health-promoting by-products useful in cardiovascular disease management.

Functional Polymers for Controlled Drug Release

In the last decade, the pharmaceutical application of hydrophilic materials has emerged as one of the most significant trends in the biomedical and pharmaceutical areas [...].

Sangiovese cv Pomace Seeds Extract-Fortified Kefir Exerts Anti-Inflammatory Activity in an In Vitro Model of Intestinal Epithelium Using Caco-2 Cells

Inflammatory bowel disease and food allergies are a growing topic in the field of nutrition science. Polyphenols, which are the most important secondary metabolites of plants, demonstrated to modulate the expression and/or production of numerous proteins, but also to regulate the intestinal ecosystem. In this context, our aim was the investigation of protective effects against the gastrointestinal mucosa of fortified milk kefir obtained by adding seeds extract from Sangiovese cv. Pomace. Methods: An ultrasound-assisted method was used to obtain the extracts. All the extracts were assayed for the antioxidant activity. The best extract was used as an additive of fermented milk kefir to obtain a fortified final product. Kefir samples were analyzed by NMR spectroscopy. The efficiency of the barrier functions was evaluated by measuring trans-epithelial electric resistance (TEER) using a voltmeter. Results: the enriched kefir (Ksgn) possesses higher antioxidant performances compared to the unfortified sample (Kwht). Kwht and Ksgn did not alter Caco-2 TEER in basal condition.

Injectable Hydrogels for Cancer Therapy over the Last Decade

The interest in injectable hydrogels for cancer treatment has been significantly growing over the last decade, due to the availability of a wide range of starting polymer structures with tailored features and high chemical versatility. Many research groups are working on the development of highly engineered injectable delivery vehicle systems suitable for combined chemo-and radio-therapy, as well as thermal and photo-thermal ablation, with the aim of finding out effective solutions to overcome the current obstacles of conventional therapeutic protocols. Within this work, we have reviewed and discussed the most recent injectable hydrogel systems, focusing on the structure and properties of the starting polymers, which are mainly classified into natural or synthetic sources. Moreover, mapping the research landscape of the fabrication strategies, the main outcome of each system is discussed in light of possible clinical applications.

Combining Carbon Nanotubes and Chitosan for the Vectorization of Methotrexate to Lung Cancer Cells

A hybrid system composed of multi-walled carbon nanotubes coated with chitosan was proposed as a pH-responsive carrier for the vectorization of methotrexate to lung cancer. The effective coating of the carbon nanostructure by chitosan, quantified (20% by weight) by thermogravimetric analysis, was assessed by combined scanning and transmission electron microscopy, and X-ray photoelectron spectroscopy (N1s signal), respectively. Furthermore, Raman spectroscopy was used to characterize the interaction between polysaccharide and carbon counterparts. Methotrexate was physically loaded onto the nanohybrid and the release profiles showed a pH-responsive behavior with higher and faster release in acidic (pH 5.0) vs. neutral (pH 7.4) environments. Empty nanoparticles were found to be highly biocompatible in either healthy (MRC-5) or cancerous (H1299) cells, with the nanocarrier being effective in reducing the drug toxicity on MRC-5 while enhancing the anticancer activity on H1299.

Recent Advances in the Synthesis and Biomedical Applications of Nanocomposite Hydrogels

Hydrogels sensitive to electric current are usually made of polyelectrolytes and undergo erosion, swelling, de-swelling or bending in the presence of an applied electric field. The electrical conductivity of many polymeric materials used for the fabrication of biomedical devices is not high enough to achieve an effective modulation of the functional properties, and thus, the incorporation of conducting materials (e.g., carbon nanotubes and nanographene oxide) was proposed as a valuable approach to overcome this limitation. By coupling the biological and chemical features of both natural and synthetic polymers with the favourable properties of carbon nanostructures (e.g., cellular uptake, electromagnetic and magnetic behaviour), it is possible to produce highly versatile and effective nanocomposite materials. In the present review, the recent advances in the synthesis and biomedical applications of electro-responsive nanocomposite hydrogels are discussed.

Coated biodegradable casein nanospheres: a valuable tool for oral drug delivery

Biodegradable casein nanospheres for the sustained release of bioactive molecules in the gastro-intestinal tract were prepared by precipitation polymerization using sodium methacrylate (NaMA) and N,N'-methylene bis-acrylamide (MEBA) as pH-responsive monomer and cross-linker. Three materials with different casein amount were obtained and characterized by scanning electron microscopy, dimensional analysis, water uptake, cytotoxicity and enzymatic degradation experiments. Nanospheres biodegradability was tuned by coating with polyacrylic acid. Coated and uncoated materials were investigated as delivery vehicles for diclofenac sodium salt. For un-coated samples, the release raise 100% in 30 h, while for coated specimens these values were lower than 70%, due to the diffusional constraints of polymer layer.

Carbon nanotubes hybrid hydrogels in drug delivery: a perspective review

The use of biologics, polymers, silicon materials, carbon materials, and metals has been proposed for the preparation of innovative drug delivery devices. One of the most promising materials in this field are the carbon-nanotubes composites and hybrid materials coupling the advantages of polymers (biocompatibility and biodegradability) with those of carbon nanotubes (cellular uptake, stability, electromagnatic, and magnetic behavior). The applicability of polymer-carbon nanotubes composites in drug delivery, with particular attention to the controlled release by composites hydrogel, is being extensively investigated in the present review.

Synthesis, characterization and antimicrobial activity of conjugates based on fluoroquinolon-type antibiotics and gelatin

Different fluoroquinolon-type antibiotics were conjugated to gelatin with the aim to synthesize biomacromolecules with antimicrobial properties. The covalent linkage of the antibiotic was performed by a radical process involving the residues in the side chains of gelatin able to undergo oxidative modifications. The conjugation of antibiotic moieties onto the protein structure was confirmed by FT-IR, UV-Vis, fluorescence, and calorimetric analyses. Biocompatibility tests were performed on human bone marrow mesenchymal stromal cells and the antibacterial properties of bioactive polymers were investigated by appropriate tests against Klebsiella pneumoniae and Escherichia coli. With regard to the tests conducted in the presence of E. coli, a minimum inhibitory concentration (MIC) ranging from 0.05 to 0.40 μg mL(-1) was recorded, while in the presence of K. pneumoniae this concentration varies from 0.10 to 1.60 μg mL(-1). In all the conjugates, the drug moieties retain their biological activity and the MIC values are lower than the resistance parameters of fluoroquinolon-type antibiotics versus Enterobacteriacae. The collected data suggest a broad range of applications, from biomedical to pharmaceutical and food science for all conjugates.

Flavonoid-based pH-responsive hydrogels as carrier of unstable drugs in oxidative conditions

In this study, pH-responsive hydrogels, synthesized by the coupling reaction of polyacrylic acid and catechin, are proposed as carriers of oxidable drugs toward the GI tract. The presence of polyphenolic moieties in the network gives the polymers properties suitable for the release of unstable drugs in oxidative conditions. The characterization of the hydrogels is obtained by means of morphological and physico-chemical analyses, antioxidant assays and evaluation of the swelling behavior in media simulating the gastric (pH 1.0) and the intestinal (pH 7.4) tracts. The hydrogels are tested as pH-responsive carriers in in vitro release studies of folic acid and thiamine, two model drugs easily degraded by oxidative conditions simulated by UV irradiation and t-butyl hydroperoxide treatment, respectively. Results show that catechin-based carriers are able to control the release of drugs at different pH values, giving a remarkable improvement in the stability of the therapeutics.

Ciprofloxacin-collagen conjugate in the wound healing treatment

The synthesis of a novel functional biomaterial for wound healing treatment was carried out by adopting a free-radical grafting procedure in aqueous media. With this aim, ciprofloxacin (CFX) was covalently incorporated into collagen (T1C) chains employing an ascorbic acid/hydrogen peroxide redox pair as biocompatible initiator system. The covalent insertion of CFX in the polymeric chains was confirmed by FT-IR and UV analyses, while an antibacterial assay demonstrated the activity of the synthesized conjugate against Staphylococcusaureus and Escherichia coli, microorganisms that commonly infect wounds. A catechin blended conjugate was also tested in order to evaluate the ability to influence fibroblast cell growth. The observed antibacterial activity and stimulation of fibroblast growth support the applicability of CFX-T1C conjugate in wound treatment encouraging the healing process.

Temperature-sensitive hydrogels by graft polymerization of chitosan and N-isopropylacrylamide for drug release

Thermo-responsive polysaccharidic hydrogels were designed and synthesized by a free radical induced grafting procedure. Chitosan was chosen as biopolymer to impart biocompatibility and biodegradability to the macromolecular systems, while N-isopropylacrylamide (NIPAAm) was selected as co-monomer responsive for the thermo-sensitive properties. Ammonium persulfate was the initiator system and different polymeric networks have been synthesized by modulating the amount of NIPAAm in the polymerization feed. The resulting hydrogels were proposed as drug delivery devices and their performance was evaluated by using Diclofenac sodium salt as a model drug. Hydrogels were carefully characterized by FT-IR spectrophotometry, calorimetric analyses and swelling behavior in a temperature range of 15-45°C. Finally, to verify the suitability of these hydrogels as thermo-responsive devices, the drug release profiles were studied performing in vitro experiments around the swelling-shrinking transition temperatures of the macromolecular systems.

Selective determination of melamine in aqueous medium by molecularly imprinted solid phase extraction

A molecularly imprinted polymer able to recognize melamine in partially aqueous medium was synthesized using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linking agent. The bound specificity and selectivity of the obtained material were verified by performing binding experiments with melamine and its structural analogue, 2,4,6-trimethoxy-1,3,5-triazine, respectively, using different aqueous binding media. Finally, the ability of MIP to selectively extract melamine from two real samples, a food supplement and a freeze-dried meat sample, was demonstrated.

Antioxidant multi-walled carbon nanotubes by free radical grafting of gallic acid: new materials for biomedical applications

OBJECTIVES

To prove the possibility of covalently functionalizing multi-walled carbon nanotubes (CNTs) by free radical grafting of gallic acid on their surface with the subsequent synthesis of materials with improved biological properties evaluated by specific in-vitro assays.

METHODS

Antioxidant CNTs were synthesized by radical grafting of gallic acid onto pristine CNTs. The synthesis of carbon nanotubes was carried out in a fixed-bed reactor and, after the removal of the amorphous carbon, the grafting process was performed. The obtained materials were characterized by fluorescence and Fourier transform infrared spectroscopy (FT-IR) analyses. After assessment of the biocompatibility and determination of the disposable phenolic group content, the antioxidant properties were evaluated in terms of total antioxidant activity and scavenger ability against 2,2'-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl and peroxyl radicals. Finally the inhibition activity on acetylcholinesterase was evaluated.

KEY FINDINGS

  The covalent functionalization of CNTs with gallic acid was confirmed and the amount of gallic acid bound per g of CNTs was found to be 2.1±0.2 mg. Good antioxidant and scavenging properties were recorded in the functionalized CNTs, which were found to be able to inhibit the acetylcholinesterase with potential improved activity for biomedical and pharmaceutical applications.

CONCLUSIONS

For the first time, a free radical grafting procedure was proposed as a synthetic approach for the covalent functionalization of CNTs with an antioxidant polyphenol.

Synthesis of stimuli-responsive microgels for in vitro release of diclofenac diethyl ammonium

Thermal and dual stimuli-responsive microspheres (pH and temperature) were prepared by free radical polymerization of methacrylate bovine serum albumin (BSA-MA) as cross-linker and sodium methacrylate (NaMA) and/or N-isopropylacrylamide (NIPAAm), as hydrophilic/pH-sensitive and thermo-responsive monomers, respectively. Microgels were characterized by infrared spectroscopy, morphological analysis, particle size distribution and determination of swelling properties. The network density and the shape of the microgels were found to depend on the concentration of the reactive species in the polymerization feed. Thermal analyses were performed to determine lower critical solution temperature values, which become close to the body temperature by increasing the content of the hydrophilic moieties in the network. In order to test the preformed materials as drug carriers, in vitro release studies of Diclofenac diethyl ammonium salt were performed. For all the co-polymers, a predominant drug release in the collapsed state was observed, while below the microgel transition temperature, a drug release through the swollen network occurs. The data recorded during the release tests demonstrated that the pH of the surrounding environment influences the drug release more than the temperature of the imbibing medium.

Selective recognition of methotrexate by molecularly imprinted polymers

The aim of this study is the preparation of molecularly imprinted polymers with high selectivity for metotrexate (MTX), a useful antineoplastic drug widely employed in clinical trials. Methacrylic acid, 2-(dimethylamino)ethyl methacrylate and a mixture of them were tested as functional monomers in order to optimize the performance of imprinted materials. The specificity and the selectivity of imprinted polymers was tested by performing rebinding experiments in water at pH 7.4. The best results were obtained by employing both functional monomers in the polymeric feed. In this way, each monomer interacts with complementary functionalities on template molecule, stabilizing the prepolymerization complex and minimizing the repulsive effects (due to the ionization of functional groups) in the rebinding media.

Covalent insertion of antioxidant molecules on chitosan by a free radical grafting procedure

In this work, the synthesis of gallic acid-chitosan and catechin-chitosan conjugates was carried out by adopting a free radical-induced grafting procedure. For this purpose, an ascorbic acid/hydrogen peroxide redox pair was employed as radical initiator. The formation of covalent bonds between antioxidant and biopolymer was verified by performing UV, FT-IR, and DSC analyses, whereas the antioxidant properties of chitosan conjugates were compared with that of a blank chitosan, treated in the same conditions but in the absence of antioxidant molecules. The good antioxidant activity shown by functionalized materials proved the efficiency of the reaction method.