Characterization of Grape Pomace Extract Microcapsules: The Influence of Carbohydrate Co-Coating on the Stabilization of Goat Whey Protein as a Primary Coating.

Both grape pomace and whey are waste products from the food industry that are rich in valuable ingredients. The utilization of these two by-products is becoming increasingly possible as consumer awareness of upcycling increases. The biological activities of grape pomace extract (GPE) are diverse and depend on its bioavailability, which is influenced by processes in the digestive system. In this work, goat whey protein (GW) was used as the primary coating to protect the phenolic compounds of GPE during the spray drying process. In addition, trehalose (T), sucrose (S), xylose (X), and maltodextrin (MD) were added to the goat whey proteins as co-coatings and protein stabilizers. All spray drying experiments resulted in microcapsules (MC) with a high encapsulation efficiency (77.6-95.5%) and yield (91.5-99.0%) and almost 100% recovery of phenolic compounds during the release test. For o-coumaric acid, the GW-coated microcapsules (MC) showed a bioavailability index of up to 731.23%. A semi-crystalline structure and hydrophilicity were characteristics of the MC coated with 10% T, S, X, or 5% MD. GW alone or in combination with T, S, MD, or X proved to be a promising carrier for polyphenols from grape pomace extract and ensured good bioavailability of these natural antioxidants.

The Release of Grape Pomace Phenolics from Alginate-Based Microbeads during Simulated Digestion In Vitro: The Influence of Coatings and Drying Method.

Grape pomace is a byproduct of wineries and a sustainable source of bioactive phenolic compounds. Encapsulation of phenolics with a well-chosen coating may be a promising means of delivering them to the intestine, where they can then be absorbed and exert their health-promoting properties, including antioxidant, anti-inflammatory, anticancer, cardioprotective, and antimicrobial effects. Ionic gelation of grape pomace extract with natural coatings (sodium alginate and its combination with maltodextrins, gelatin, chitosan, gums Tragacanth and Arabic) was performed, and the resulting hydrogel microbeads were then air-, vacuum-, and freeze-dried to prevent spoilage. Freeze-drying showed advantages in preserving the geometrical parameters and morphology of the microbeads compared to other drying techniques. A good relationship was found between the physicochemical properties of the dried microbeads and the in vitro release of phenolics. Freeze-dried microbeads showed the highest cumulative release of phenols in the intestinal phase (23.65-43.27 mgGAE/gMB), while the most suitable release dynamics in vitro were observed for alginate-based microbeads in combination with gelatin, gum Arabic, and 1.5% (w/v) chitosan. The results highlight the importance of developing encapsulated formulations containing a natural source of bioactive compounds that can be used in various functional foods and pharmaceutical products.

In Vitro Bioaccessibility Assessment of Phenolic Compounds from Encapsulated Grape Pomace Extract by Ionic Gelation.

Grape pomace is a by-product of winemaking characterized by a rich chemical composition from which phenolics stand out. Phenolics are health-promoting agents, and their beneficial effects depend on their bioaccessibility, which is influenced by gastrointestinal digestion. The effect of encapsulating phenol-rich grape pomace extract (PRE) with sodium alginate (SA), a mixture of SA with gelatin (SA-GEL), and SA with chitosan (SA-CHIT) on the bioaccessibility index (BI) of phenolics during simulated digestion in vitro was studied. A total of 27 individual phenolic compounds (IPCs) were quantified by UHPLC. The addition of a second coating to SA improved the encapsulation efficiency (EE), and the highest EE was obtained for SA-CHIT microbeads (56.25%). Encapsulation affected the physicochemical properties (size, shape and texture, morphology, crystallinity) of the produced microbeads, which influenced the delivery of phenolics to the intestine and their BI. Thus, SA-GEL microbeads had the largest size parameters, as confirmed by scanning electron microscopy (SEM), and the highest BI for total phenolic compounds and IPCs (gallic acid, 3,4-dihydroxybenzoic acid and o-coumaric acid, epicatechin, and gallocatechin gallate) ranged from 96.20 to 1011.3%. The results suggest that encapsulated PRE has great potential to be used as a functional ingredient in products for oral administration.

Bioconversion of Grape Pomace with Rhizopus oryzae under Solid-State Conditions: Changes in the Chemical Composition and Profile of Phenolic Compounds.

Grape pomace is a sustainable source of bioactive phenolic compounds used in various industries. The recovery of phenolic compounds could be improved by biological pretreatment of grape pomace, as they are released from the lignocellulose structure by the activity of the enzymes produced. The influence of grape pomace pretreatment with Rhizopus oryzae under solid-state conditions (SSF) on the phenolic profile and chemical composition changes was studied. SSF was performed in laboratory jars and in a tray bioreactor for 15 days. Biological pretreatment of grape pomace resulted in an increase in the content of 11 individual phenolic compounds (from 1.1 to 2.5-fold). During SSF, changes in the chemical composition of the grape pomace were observed, including a decrease in ash, protein, and sugar content, and an increase in fat, cellulose, and lignin content. A positive correlation (r > 0.9) was observed between lignolytic enzymes and the hydrolytic enzyme's xylanase and stilbene content. Finally, after 15 days of SSF, a weight loss of GP of 17.6% was observed. The results indicate that SSF under experimental conditions is a sustainable bioprocess for the recovery of phenolic compounds and contributes to the zero-waste concept by reducing waste.

Physicochemical Characterization and Evaluation of Gastrointestinal In Vitro Behavior of Alginate-Based Microbeads with Encapsulated Grape Pomace Extracts.

Grape pomace is a byproduct of wineries and a rich source of phenolic compounds that can exert multiple pharmacological effects when consumed and enter the intestine where they can then be absorbed. Phenolic compounds are susceptible to degradation and interaction with other food constituents during digestion, and encapsulation may be a useful technique for protecting phenolic bioactivity and controlling its release. Therefore, the behavior of phenolic-rich grape pomace extracts encapsulated by the ionic gelation method, using a natural coating (sodium alginate, gum arabic, gelatin, and chitosan), was observed during simulated digestion in vitro. The best encapsulation efficiency (69.27%) was obtained with alginate hydrogels. The physicochemical properties of the microbeads were influenced by the coatings used. Scanning electron microscopy showed that drying had the least effect on the surface area of the chitosan-coated microbeads. A structural analysis showed that the structure of the extract changed from crystalline to amorphous after encapsulation. The phenolic compounds were released from the microbeads by Fickian diffusion, which is best described by the Korsmeyer-Peppas model among the four models tested. The obtained results can be used as a predictive tool for the preparation of microbeads containing natural bioactive compounds that could be useful for the development of food supplements.

Antioxidant and antiproliferative potentials of phenolic-rich extracts from biotransformed grape pomace in colorectal Cancer.

BACKGROUND: Colorectal carcinoma is one of the most commonly diagnosed malignancies worldwide. Consumption of dietary supplements and nutraceuticals such as phenolic compounds may help combat colorectal carcinoma. The effect of two phenolic-rich extracts prepared from biotransformed grape pomace on the antioxidant properties and antiproliferative activity against two colorectal cancer cell lines (Caco-2 and SW620) were investigated. METHODS: A 15-day solid-state fermentation with the white-rot fungi Phanerochaete chrysosporium and Trametes gibbosa was used to biotransform grape pomace. Solid-liquid extraction was then performed to extract bioactive compounds. The extract was analyzed for the determination of phenolic compounds by ultra-high performance liquid chromatography and in vitro assays of biological activities (antioxidant activity, antiproliferative activity, cell cycle analysis). RESULTS: The 4 days of solid-state fermentation proved to be the optimal period to obtain the maximum yield of phenolic compounds. The tested extracts showed significant antioxidant and antiproliferative activities. Grape pomace treated with P. chrysosporium and T. gibbosa reduced cancer cell growth by more than 60% at concentrations (solid/liquid ratio) of 1.75 mg/mL and of 2.5 mg/mL, respectively. The cell cycle perturbations induced by the grape pomace extracts resulted in a significant increase in the number of cells in the S (9.8%) and G2/M (6.8%) phases of SW620 exposed to T. gibbosa after 48 hours, while P. chrysosporium increased the percentage of cells in the G1 phase by 7.7%. The effect of grape pomace extracts on Caco-2 was less pronounced. CONCLUSIONS: The obtained results suggest the presence of bioactive compounds in biotransformed grape pomace as a residue from winemaking, which could be used to prevent colon cancer.

Improvement of the Nutraceutical Profile of Brewer's Spent Grain after Treatment with Trametes versicolor.

Brewer's spent grain (BSG) is an important secondary raw material that provides a readily available natural source of nutraceuticals. It finds its largest application as animal feed and part of the human diet, while the future perspective predicts an application in the production of value-added products. In order to investigate a sustainable BSG treatment method, two BSG samples (BSG1 and BSG2) were evaluated as substrates for the production of hydrolytic (xylanase, ß-glucosidase and cellulase) and lignolytic enzymes (laccase, manganese peroxidase and lignin peroxidase) by solid-state fermentation (SSF) with Trametes versicolor while improving BSG nutritional value. The biological treatment was successful for the production of all hydrolytic enzymes and laccase and manganese peroxidase, while it was unsuccessful for the production of lignin peroxidase. Because the two BSGs were chemically different, the Trametes versicolor enzymes were synthesized at different fermentation times and had different activities. Consequently, the chemical composition of the two BSG samples at the end of fermentation was also different. The biological treatment had a positive effect on the increase in protein content, ash content, polyphenolic compounds, and sugars in BSG1. In BSG2, there was a decrease in the content of reducing sugars. Cellulose, hemicellulose, and lignin were degraded in BSG1, whereas only cellulose was degraded in BSG2, and the content of hemicellulose and lignin increased. The fat content decreased in both samples. The safety-related correctness analysis showed that the biologically treated sample did not contain any harmful components and was therefore safe for use in nutritionally enriched animal feed.

The Potential of Brewer's Spent Grain in the Circular Bioeconomy: State of the Art and Future Perspectives.

Brewer's spent grain (BSG) accounts for approximately 85% of the total mass of solid by-products in the brewing industry and represents an important secondary raw material of future biorefineries. Currently, the main application of BSG is limited to the feed and food industry. There is a strong need to develop sustainable pretreatment and fractionation processes to obtain BSG hydrolysates that enable efficient biotransformation into biofuels, biomaterials, or biochemicals. This paper aims to provide a comprehensive insight into the availability of BSG, chemical properties, and current and potential applications juxtaposed with the existing and emerging markets of the pyramid of bio-based products in the context of sustainable and circular bioeconomy. An economic evaluation of BSG for the production of highly valuable products is presented in the context of sustainable and circular bioeconomy targeting the market of Central and Eastern European countries (BIOEAST region).

A Comparative Study of the Influence of Various Fungal-Based Pretreatments of Grape Pomace on Phenolic Compounds Recovery.

Wineries produce considerable amounts of grape pomace, which is a readily available natural source of bioactive phenolic compounds. In this study, grape pomace was used as a substrate for the cultivation of eleven filamentous fungi (Trametes versicolor TV6, Trametes versicolor TV8, Trametes versicolor AG613, Trametes gibbosa, Phanerochaete chrysosporium, Ceriporiopsis subvermispora, Pleurotus eryngii, Ganoderma lucidum, Ganoderma resinaceum, Humicola grisea, and Rhizopus oryzae) under solid-state conditions (SSF) for 15 days with the aim of improving the recovery of the individual phenolic compounds. Twenty-one phenolic compounds were quantified and the recovery of seventeen of them (gallic acid, ellagic acid, p-hydroxybenzoic acid, syringic acid, vanillic acid, 3,4-dihydroxybenzoic acid, ferulic acid, o-coumaric acid, p-coumaric acid, epicatechin gallate, galocatechin gallate, quercetin, kaempferol, procyanidin B1, procyanidin B2, resveratrol, and ε-viniferin) were positively affected by SSF. Ellagic acid is the most recovered compound, whose content increased 8.8-fold after 15 days of biological treatment with Ceriporiopsis subvermispora compared to the untreated initial sample. Among the microorganisms tested, the fungi Pleurotus eryngii and Rhizopus oryzae proved to be the most effective in increasing the recovery of most phenolic compounds (1.1-4.5-fold). In addition, the nutrient composition (proteins, ash, fats) of grape pomace was positively affected by the biological treatments.

A Comprehensive Review on Valorization of Agro-Food Industrial Residues by Solid-State Fermentation.

Agro-food industrial residues (AFIRs) are generated in large quantities all over the world. The vast majority of these wastes are lignocellulosic wastes that are a source of value-added products. Technologies such as solid-state fermentation (SSF) for bioconversion of lignocellulosic waste, based on the production of a wide range of bioproducts, offer both economic and environmental benefits. The versatility of application and interest in applying the principles of the circular bioeconomy make SSF one of the valorization strategies for AFIRs that can have a significant impact on the environment of the wider community. Important criteria for SSF are the selection of the appropriate and compatible substrate and microorganism, as well as the selection of the optimal process parameters for the growth of the microorganism and the production of the desired metabolites. This review provides an overview of the management of AFIRs by SSF: the current application, classification, and chemical composition of AFIRs; the catalytic function and potential application of enzymes produced by various microorganisms during SSF cultivation on AFIRs; the production of phenolic compounds by SSF; and a brief insight into the role of SSF treatment of AFIRs for feed improvement and biofuel production.

Trametes versicolor in lignocellulose-based bioeconomy: State of the art, challenges and opportunities.

Although Trametes versicolor is one of the most investigated white-rot fungi, the industrial application of this fungus and its metabolites is still far from reaching its full potential. This review aims to highlight the opportunities and challenges for the industrial use of T. versicolor according to the principles of circular bioeconomy. The use of this fungus can contribute significantly to the success of efforts to valorize lignocellulosic waste biomass and industrial lignocellulosic byproducts. Various techniques of T. versicolor cultivation for enzyme production, food and feed production, wastewater treatment, and biofuel production are listed and critically evaluated, highlighting bottlenecks and future perspectives. Applications of T. versicolor crude laccase extracts in wastewater treatment, removal of lignin from lignocellulose, and in various biotransformations are analyzed separately.

Transesterification of Sunflower Oil over Waste Chicken Eggshell-Based Catalyst in a Microreactor: An Optimization Study.

The statistical experimental design (DoE) and optimization (Response Surface Methodology combined with Box-Behnken design) of sunflower oil transesterification catalyzed by waste chicken eggshell-based catalyst were conducted in a custom-made microreactor at 60 °C. The catalyst was synthesized by the hydration-dehydration method and subsequent calcination at 600 °C. Comprehensive characterization of the obtained catalyst was conducted using: X-ray powder diffractometry (XRD), X-ray fluorescence (XRF), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), N2 physisorption, and Hg-porosimetry. Structural, morphological, and textural results showed that the obtained catalyst exhibited high porosity and regular dispersity of plate-like CaO as an active species. The obtained optimal residence time, catalyst concentration, and methanol/oil volume ratio for the continuous reaction in microreactor were 10 min, 0.1 g g-1, and 3:1, respectively. The analysis of variance (ANOVA) showed that the obtained reduced quadratic model was adequate for experimental results fitting. The reaction in the microreactor was significantly intensified compared to a conventional batch reactor, as seen through the fatty acid methyl esters (FAMEs) content after 10 min, which was 51.2% and 18.6%, respectively.

Role of the Encapsulation in Bioavailability of Phenolic Compounds.

Plant-derived phenolic compounds have multiple positive health effects for humans attributed to their antioxidative, anti-inflammatory, and antitumor properties, etc. These effects strongly depend on their bioavailability in the organism. Bioaccessibility, and consequently bioavailability of phenolic compounds significantly depend on the structure and form in which they are introduced into the organism, e.g., through a complex food matrix or as purified isolates. Furthermore, phenolic compounds interact with other macromolecules (proteins, lipids, dietary fibers, polysaccharides) in food or during digestion, which significantly influences their bioaccessibility in the organism, but due to the complexity of the mechanisms through which phenolic compounds act in the organism this area has still not been examined sufficiently. Simulated gastrointestinal digestion is one of the commonly used in vitro test for the assessment of phenolic compounds bioaccessibility. Encapsulation is a method that can positively affect bioaccessibility and bioavailability as it ensures the coating of the active component and its targeted delivery to a specific part of the digestive tract and controlled release. This comprehensive review aims to present the role of encapsulation in bioavailability of phenolic compounds as well as recent advances in coating materials used in encapsulation processes. The review is based on 258 recent literature references.

Enhancement of the anti-inflammatory properties of grape pomace treated by Trametes versicolor.

The application of solid-state fermentation for the production of value-added products from the agro- and food-industry residues has been recently investigated greatly. The white-rot basidiomycete Trametes versicolor is a widely used fungi for the degradation lignocellulosic material in solid-state conditions. Grape pomace constitutes the major by-product of Vitis vinifera L. and is a source of compounds with recognized health benefits. In this study, a process for treating grape pomace with Trametes versicolor for 15 days under solid-state conditions was developed, and the phenolic profile and anti-inflammatory potential of the grape pomace extracts before and after treatment was studied. The anti-inflammatory potential of the grape pomace extracts was studied via tests based on the inhibition of 5-lipoxygenase and hyaluronidase, two key enzymes in inflammatory processes. A total of 24 phenolic compounds were identified and quantified by HPLC methods. With the exception of anthocyanins, an increase in phenolic acids, flavan-3-ols and the flavonol rutin was observed after a treatment period of 1-4 days with T. versicolor. Moreover, the increase in the phenolic content was accompanied by an enhancement in the anti-inflammatory activity of the grape pomace extracts, which was confirmed by the strong correlation between them. This is the first study providing evidence of the benefits of the application of fungal-based solid-state fermentation as an environmentally friendly process for the enhancement of the phenolic composition and anti-inflammatory potential of grape pomace, increasing the possibility of profiting from the great waste produced by the grape-processing industry.

Corn silage fungal-based solid-state pretreatment for enhanced biogas production in anaerobic co-digestion with cow manure.

The objective of this research was to use white-rot fungus Trametes versicolor for corn silage pretreatment and to investigate the effect of pretreatment on biogas productivity. Semi-continuous pilot-scale experiment, comprised of two experimental phases, was carried out. In the first phase, operational conditions of the full-scale biogas plant were reproduced at pilot-scale. In that phase, the reactor was daily fed with the mixture of cow manure, digestate from industrial postfermentor, corn grits and ensiled corn silage, and the average methane generation rate was 0.167 m3CH4 kgVS-1. In the second phase, corn grits and ensiled corn silage were replaced with corn silage pretreated with T. versicolor, and the average methane generation rate increased up to 0.236 m3CH4 kgVS-1. The results of this study suggest that application of fungal-based solid-state pretreated corn silage has positive effect on pH stability and increase the biogas productivity.

Recovery of Phenolic Acid and Enzyme Production from Corn Silage Biologically Treated by Trametes versicolor.

Corn silage is used as high-energy forage for dairy cows and more recently for biogas production in a process of anaerobic co-digestion with cow manure. In this work, fresh corn silage after the harvest was used as a substrate in solid-state fermentations with T. versicolor with the aim of phenolic acid recovery and enzyme (laccase and manganese peroxidase) production. During 20 days of fermentation, 10.4-, 3.4-, 3.0-, and 1.8-fold increments in extraction yield of syringic acid, vanillic acid, p-hydroxybenzoic acid, and caffeic acid, respectively, were reached when compared to biologically untreated corn silage. Maximal laccase activity was gained on the 4th day of fermentation (V.A. = 180.2 U/dm3), and manganese peroxidase activity was obtained after the 3rd day of fermentation (V.A. = 30.1 U/dm3). The addition of copper(II) sulfate as inducer during solid state fermentation resulted in 8.5- and 7-fold enhancement of laccase and manganese peroxidase activities, respectively. Furthermore, the influence of pH and temperature on enzyme activities was investigated. Maximal activity of laccase was obtained at T = 50 °C and pH = 3.0, while manganese peroxidase is active at temperature range T = 45-70 °C with the maximal activity at pH = 4.5.

Corn forage biological pretreatment by Trametes versicolor in a tray bioreactor.

Trametes versicolor is a white-rot fungus known to be efficient in lignin removal due to its complex extracellular lignocellulolytic enzymatic system. Therefore, it can be used in the treatment of lignocellulose waste from agro, food, and wood industries. In a first experiment, corn forage treatment with T. versicolor was investigated in laboratory jars. In a second experiment, the process was scaled up to a tray bioreactor. In the tray bioreactor, the process of lignin degradation was improved, resulting in an increase in lignin conversion of up to 71% during seven days' treatment.

Temperature-dependent kinetics of grape seed phenolic compounds extraction: experiment and model.

The kinetics of a batch solid-liquid extraction of total phenolic compounds (PC) from milled grape seed (Vitis vinifera L. cv. "Frankovka") using 50% ethanol at different extraction temperatures (25-80°C) was studied. The maximum yield of PC was 0.13 kg(GAE)/kg(db) after 200 min of extraction in agitated vessel at 80°C. A new model based on the assumptions of a first order kinetics mechanism for the solid-liquid extraction and a linear equilibrium at the solid-liquid interface was developed. The model involves the concept of broken and intact cells in order to describe two successive extraction periods: a very fast surface washing process followed by slow diffusion of phenolic compounds from grape seeds to the solvent. The proposed model is suited to fit experimental data and to simulate the extraction of phenolic compounds, which was confirmed by the correlation coefficient (r≥0.965), the root mean square error (RMSE≤0.003 kg(GAE)/kg(db)) and the mean relative deviation modulus (E≤2.149%). The temperature influenced both equilibrium partition coefficients of phenolic compounds and transport properties, which is manifested by a relatively high value of activation energy (23-24) kJ/mol and by values of effective diffusivity in seed particles.