Grape Marc Research Articles

Growth media change Eisenia fetida epithelium thickness: implications for improving earthworm welfare in vermicomposting systems.

Because the earthworm tegument represents their first barrier against environmental aggressions, we hypothesised that substrate-induced changes in earthworm growth would also alter the morphology of this protective layer. Therefore, a histological and morphometric study was performed on Eisenia fetida specimens that have been grown in five different organic residues: cow manure, horse manure, grape marc, coffee grounds, and a mixture of coffee grounds and cooking oil. The results showed that, across all treatments, both cuticle and epidermis were significantly thicker in the pre-clitellar region than after the clitellum, attributed to the fact that the former region is responsible for breaking up the soil. Notably, the growing media significantly altered the thickness of these two integumentary layers, and the greatest thicknesses were measured in grape marc and in the mixture coffee grounds + cooking oil, which makes them suitable organic residues for vermicomposting. By contrary, a significant epidermal thinning was observed when growing on coffee grounds alone, clearly indicating that it is a hostile environment for earthworms. Overall, these results reveal that tegument thickness can be used not only as a trait indicator of substrate quality but also of earthworm welfare, and it should be integrated in future toxicity assessment and captive breeding guidelines.

The role of plant-derived melanin in enhancing <i>in vitro</i> growth and nutrient accumulation in potato varieties

Background: Melanins are versatile biopolymers found in a wide range of living organisms, contributing to the diverse colors observed in nature. Beyond their pigmentation role, melanins exhibit a variety of biological activities, including antioxidant, antitoxic, antitumor, photoprotective, antimicrobial, and radioprotective properties. These attributes make melanins valuable in fields such as medicine, pharmaceuticals, and agriculture. In this study, we investigated grape marc, a byproduct of wine production, as a novel source of water-soluble melanin extracted using sodium hydroxide. This approach not only repurposes agricultural waste but also explored melanin's role in optimizing in vitro plant cultivation. We evaluated the impact of melanin on the biochemical properties of potato plants, focusing on improvements in growth, rhizogenesis, and the nutritional composition of tubers. Objective: The aim of this study was to evaluate the effects of plant-derived melanin on the in vitro growth characteristics and biochemical composition of two potato varieties. Methods: This study took place in the tissue culture laboratory at the Scientific Center of Agrobiotechnology from 2021 to 2024. Apical meristems from the Nevsky and Impala potato varieties were used for in vitro regeneration. The research focused on the in vitro growth and adaptation of these plants under different melanin concentrations. Key growth parameters, chlorophyll content, and biochemical composition were analyzed to assess the impact of melanin on potato development. Results: The study found that melanin at a concentration of 0.028% significantly enhanced the in vitro growth and rhizogenesis of potato microstems, with optimal results in root number (12.30 per shoot) and shoot length (16.91 cm). Plants also showed earlier and more vigorous root formation, resembling an auxin-like effect. Higher melanin concentrations reduced these benefits. Additionally, plants treated with 0.028% melanin had a high acclimatization success rate (96%) and improved biochemical composition in tubers, with increases in dry matter, sugars, starch, and ascorbic acid, particularly in the Nevsky variety. Conclusion: Melanin significantly stimulated the in vitro growth and development of potato plants. Increasing melanin levels to an optimal threshold accelerated rhizogenesis and promoted vigorous root and shoot growth, evidenced by increased length and thickness. Acting similarly to auxin, melanin not only encouraged root formation but also enhanced shoot development, leading to improved plant adaptation. Additionally, melanin influenced the biochemical composition of potato tubers, including their nutritional content. These findings highlight the crucial role of melanin concentration in optimizing the growth and biochemical properties of potato varieties. Keywords: in vitro propagation, potato, melanin, plant adaptation, biochemical compound, micropropagation

Sustainable and Reusable Modified Membrane Based on Green Gold Nanoparticles for Efficient Methylene Blue Water Decontamination by a Photocatalytic Process.

Methylene blue (MB) is a dye hazardous pollutant widely used in several industrial processes that represents a relevant source of water pollution. Thus, the research of new systems to avoid their environmental dispersion represents an important goal. In this work, an efficient and sustainable nanocomposite material based on green gold nanoparticles for MB water remediation was developed. Starting from the reducing and stabilizing properties of some compounds naturally present in Lambrusco winery waste (grape marc) extracts, green gold nanoparticles (GM-AuNPs) were synthesized and deposited on a supporting membrane to create an easy and stable system for water MB decontamination. GM-AuNPs, with a specific plasmonic band at 535 nm, and the modified membrane were first characterized by UV-vis spectroscopy, X-ray diffraction (XRD), and electron microscopy. Transmission electron microscopy analysis revealed the presence of two breeds of crystalline shapes, triangular platelets and round-shaped penta-twinned nanoparticles, respectively. The crystalline nature of GM-AuNPs was also confirmed from XRD analysis. The photocatalytic performance of the modified membrane was evaluated under natural sunlight radiation, obtaining a complete disappearance of MB (100%) in 116 min. The photocatalytic process was described from a pseudo-first-order kinetic with a rate constant (k) equal to 0.044 ± 0.010 min-1. The modified membrane demonstrated high stability since it was reused up to 20 cycles, without any treatment for 3 months, maintaining the same performance. The GM-AuNPs-based membrane was also tested with other water pollutants (methyl orange, 4-nitrophenol, and rhodamine B), revealing a high selectivity towards MB. Finally, the photocatalytic performance of GM-AuNPs-based membrane was also evaluated in real samples by using tap and pond water spiked with MB, obtaining a removal % of 99.6 ± 1.2% and 98.8 ± 1.9%, respectively.

Production of grape marc kombucha: Valorization of a wine by-product

The revalorization of by-products is a priority for sustainable winemaking. This study explores the potential of white grape marc as a raw material for producing a kombucha-style beverage. We compared the fermentation processes of traditional tea kombuchas (green and black) and grape marc kombucha (Grape-K), all fermented with a homemade Symbiotic Culture of Bacteria and Yeast (SCOBY) cultured in grape marc infusion. The results demonstrated comparable acid production across all variants, with Grape-K showing enhanced sugar consumption. The microbial community was primarily composed by Brettanomyces bruxellensis (yeast), Oenococcus oeni and Liquorilactobacillus ghanensis (lactic acid bacteria), and Komagataeibacter intermedius (acetic acid bacteria). Although Grape-K contained lower levels of phenolic compounds and higher acetic acid concentrations than tea-based kombuchas, it exhibited a significant increase in antioxidant activity post-fermentation. Using Muscat grape marcs, known for their enhanced floral notes, improved the organoleptic profile of the beverage. The balance of volatile acidity with other aromatic compounds in Grape-K highlights the potential of grape marc, especially from aromatic white varieties, as a promising raw material for creating kombuchas with distinct and appealing aromatic profiles.

An Optimization of the Extraction of Phenolic Compounds from Grape Marc: A Comparison between Conventional and Ultrasound-Assisted Methods

The green extraction of total phenolic compounds, flavonoids, anthocyanins, and tannins from grape marc was optimized using response surface methodology. The extracts were characterized and analyzed using LC-ESI-QTOF-MS/MS, and free radical scavenging capacity was evaluated. An efficient green extraction method is crucial for improving the recovery rates of these high-value phytochemicals and for sustainably reusing wine by-products. Our study optimized parameters for both conventional and ultrasound-assisted extraction methods, including solution pH, extraction temperature, liquid-to-solvent ratio, and ultrasonic amplitude. The optimized conditions for conventional extraction were identified as 60% ethanol with a pH of 2, a solvent-to-solid ratio of 50:1, extraction time of 16 h at a temperature of 49.2 °C. For ultrasound-assisted extraction, the optimized conditions were determined as 60% ethanol with a pH of 2, a solvent-to-solid ratio of 50:1, and an amplitude of 100% for 5.05 min at a temperature of 60 °C. We also demonstrated that lowering the temperature to 49.5 °C improves the energy efficiency of the extraction process with a minor reduction in recovery rates. Considering all factors, ultrasound-assisted extraction is more suitable for efficiently recovering bioactive compounds from grape marc.

Compost tea and bioslurry as plant biostimulants. Part 1: characterization and phytotoxicity testing

In the present study, the quality of aerated (A), non-aerated (NA) and bioslurry (B) as potential bio-fertilizers were evaluated. Aerated and non-aerated compost teas were brewed from two different compost: exhausted grape marc (G); and a mixture of residues (M): goat manure, grape marc, garden raking leaves and alfalfa cutting hay. Bioslurry was prepared from fresh organic material in anaerobic digestion, according to FAO. Aeration, with shorter extraction time, resulted in higher pH (8.25 and 7.44 regarding 7.32 and 6.98, respectively, for AM, NAM, AG and NAG), but in general with lower nutrient concentration than non-aerated. B presented higher nitrogen content (7.86 mg L−1 N-NO3 − and 40.77 mg L−1 N-NH4 +). No pathogens or phytotoxic effects were detected. To our knowledge, this is the first time that B has been evaluated, and our results suggest that the use of fresh organic matter may generate a high-quality product to be used as a biostimulant. Agricultural bio-inputs, elaborated from organic residues, represent a cheaper and safer alternative to traditional fertilizers, while residues are reduced and reused.

Co-composting a grape marc: An influence of grape stalks and different biowastes presence on the physical - chemical parameters of the mixture

Grape pomace (GP) represents a solid residue generated after the wine-making process and includes grape marc (GM) and it contains skins, seeds, pulp and grape stalks (GS). In this work, eight different mixtures of GM and organic wastes, was observed with an aim to investigate the effect of co-supstrate and GS presence. In the first experiment, GM and co-substrates was co-composted together, in mixture M1, GM was mixed with food waste (FW), in mixture M2, GM mixed with poultry manure (PM), in M3, GM mixed with wheat straw (WS) and GM mixed with FW, PM and WS in M4. In the second experiment, in M5, GM, FW mixed with GS, in M6, GM, PM mixed with GS, in M7, GM, WS mixed with GS, and GM, FW, PM, WS mixed with GS in M8. During the co-composting, the all mixtures achieved two temperature peaks and the acidic phase lasted 10–23 days in first experiment and 6–16 days in second experiment. The loss of total OM and total C was recorded, and a total N increased from 0.58 % to 91.5 % in both experiments. The four mixtures from the both experiments showed the bigger change, reaching the C/N ratio around 15 which is characteristic of the end of process, while in the other mixtures, the C/N was higher than 20. The analyses of biodegradability showed that the six mixtures has a higher biodegradability rate (from 15.03 % to 25 %). A slight decrease in the biodegradability when is WS co-substrate (5.66 % and 5.23 %) was found. Thus, co-composting process might be suitable treatment for GM, especially when the co-subtracts are PM and FW, and GS as the bulking agent. In this way, the recycling and velarization of those wastes can be achieved, with positive environmental effects.

The Potential of Grape Polyphenols Additive in Pig Nutrition: Chemical Structure, Bioavailability and Their Effect on Intestinal Health of Pigs

The recognition of the necessity for employing natural additives in animal feed has grown alongside the ban on antibiotics in the animal feed sector. Grapes, as well as by-products of the wine-making industry (grape marc and seed extracts), possess biologically active chemical constituents that can be used to improve animal production by incorporating them into animal feed. Grapes are a valuable resource of polyphenols, especially flavonoids, stilbenes and phenolic acids, most of them showing therapeutic or health-promoting properties. The purpose of this review is to elucidate the impact of polyphenols on animal gut health. The first section of the review discusses the chemical structure of the major polyphenols in grapes and the polyphenols’ bioavailability and metabolism in pigs. The second and major part of the review reviews the results of investigations into the antioxidant, antimicrobial and prebiotic effects of grape polyphenols in pig diets, as well as their regulation of intestinal barrier functions through signalling pathways and intestinal responses. All of this is supported by previous research, findings and conclusions. There are fewer recorded pig studies, but the inclusion of up to 9% grape by-products resulted in improved performance with an increased mean daily gain. Ultimately, this analysis concluded that supplementation of pigs with grape phenolic compounds as natural feed additives enhanced their antioxidant capacity, improved humoral and cellular immune responses, and promoted gut ecosystem biodiversity and the overall production performance in pigs.

Hydrochar from winemaking industry wastes as solid biofuel: A thermal and kinetic analysis of pyrolysis and combustion

Pyrolysis and combustion behavior of the hydrochar (HY) from co-hydrothermal carbonization (co-HTC) of vine pruning (VP) and exhausted grape marc (EGM) by using vinasse as wet catalytic vector was investigated through thermogravimetric analysis (TGA). For both raw- and co-HTC biomass, different iso-conversional methods were used for kinetic analysis, and the thermodynamic parameters were determined. Overall, even if HY exhibited a lower activation energy compared to EGM and VP during both pyrolysis and combustion, HTC has positive effects on the hydrochar’s structure, which achieved a more thermodynamically stable, structurally ordered, and energetically favorable state. The obtained kinetic and thermodynamic parameters would contribute to the development of biomass thermochemical conversion technologies and the application of hydrochar-based energy systems.

Cosmetic Products with Potential Photoprotective Effects Based on Natural Compounds Extracted from Waste of the Winemaking Industry.

Grape marc is a by-product resulting from the winemaking industry that still contains beneficial compounds that can be valorized. Thus, we report here the possibility of using polyphenolic extracts of grape marc origin to obtain sun protection creams. The extractions were performed in ethanol and acetone solutions using pomace from different grape varieties (Merlot, Bläufrankisch, Fetească Neagră, Isabella) as a raw material. The obtained extracts were analyzed in order to determine the total phenolic content, the antioxidant activity, and the sun protection factor (SPF) via Mansur spectrophotometric assay. The best results were achieved using 70% ethanol in water as a solvent. The extracts with the highest potential photoprotective effects are from the Merlot variety (SPFspectrophotometric = 7.83 ± 0.76). The sunscreens were prepared using the 70% ethanolic extract of the Merlot variety evaporated to dryness, redissolved in either distilled water or ethanol. The SPF estimated in vitro via the COLIPA method showed values of 14.07 ± 1.50 and 11.46 ± 1.32 for the aqueous and ethanolic extracts, respectively, when working with a cream to polyphenolic extract a ratio of 1/1 (w/w). At the same time, the use of aqueous polyphenolic extracts ensures the better stability of creams compared with the ethanolic ones.

Emphasizing the Potential of Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) Spectroscopy Combined with Chemometrics, for Classification of Greek Grape Marc Spirits

Grape marc spirits, such as the Greek tsipouro/tsikoudia, reflect the cultural heritage of winemaking traditions worldwide. This study explored the application of Attenuated Total Reflectance–Fourier Transform Infrared (ATR-FTIR) spectroscopy combined with chemometrics for its potential as a fast classification methodology for spirit characterization. ATR-FTIR spectra from thirty-nine products revealed distinctive bands corresponding to various chemical constituents, such as alcohols, organic acids, water, carbohydrates, and phenols. Principal Component Analysis (PCA) was performed on all acquired ATR-FTIR data and 78.50% of the total variance in the data was explained. Also, partial least squares–discriminant analysis (PLS-DA), used for the classification of products based on their major geographic origin, gave a correct classification of 89.5% for the north and 83.3% for the south of Greece. Classification of the type of distillations used was with 74.36% accuracy. Significant markers were identified through analysis, such as those associated with the O-H bending vibrations of phenols or alcohols, contributing to the discrimination of grape marc spirits from Crete when compared with the other four main geographical origin designations. By combining ATR-FTIR spectroscopy with chemometrics, this research gave insights into the origins and compositional variations of the spirits, providing an opportunity for a quality control assessment tool.

Energetic, Exergetic, and Techno-Economic Analysis of A Bioenergy with Carbon Capture and Utilization Process via Integrated Torrefaction–CLC–Methanation

Bioenergy with carbon capture and storage (BECCS) or utilization (BECCU) allows net zero or negative carbon emissions and can be a breakthrough technology for climate change mitigation. This work consists of an energetic, exergetic, and economic analysis of an integrated process based on chemical looping combustion of solar-torrefied agro-industrial residues, followed by methanation of the concentrated CO2 stream with green H2. Four agro-industrial residues and four Italian site locations are considered. Depending on the considered biomass, the integrated plant processes about 18–93 kg h−1 of raw biomass and produces 55–70 t y−1 of synthetic methane. Global exergetic efficiencies ranged within 45–60% and 67–77% when neglecting and considering, respectively, the valorization of torgas. Sugar beet pulp and grape marc required a non-negligible input exergy flow for the torrefaction, due to the high moisture content of the raw biomasses. However, for these biomasses, the water released during drying/torrefaction and CO2 methanation could be recycled to the electrolyzer to eliminate external water consumption, thus allowing for a more sustainable use of water resources. For olive stones and hemp hurd, this water recycling brings, instead, a reduction of approximately 65% in water needs. A round-trip electric efficiency of 28% was estimated assuming an electric conversion efficiency of 40%. According to the economic analysis, the total plant costs ranged within 3–5 M€ depending on the biomass and site location considered. The levelized cost of methane (LCOM) ranged within 4.3–8.9 € kgCH4−1 but, if implementing strategies to avoid the use of a large temporary H2 storage vessel, can be decreased to 2.6–5.3 € kgCH4−1. Lower values are obtained when considering hemp hurd and grape marc as raw biomasses, and when locating the PV field in the south of Italy. Even in the best scenario, values of LCOM are out of the market if compared to current natural gas prices, but they might become competitive with the introduction of a carbon tax or through government incentives for the purchase of the PV field and/or electrolyzer.

Intensification of grape marc (Vitis vinifera) exploitation by subcritical water-ethanol extraction: Effect on polyphenol bioactivities and kinetic modelling

Subcritical solvent extraction (SSE) is an efficient and versatile technology for the recovery of bioactive compounds from food by-products. The present work aims to study the SSE efficiency and kinetics for the extraction of grape marc polyphenols. Water, ethanol, and a 50% water-ethanol mixture (EtOH 50%) were used as green solvents. The higher polyphenol content (4.05 ± 0.23 gGAE/100 gd. m.) and antioxidant activity (42.30 ± 0.68 mg α-toc/mL) were obtained with subcritical EtOH 50% at 120 °C and 10.3 MPa, respectively, 1.5- and 3-fold higher than the conventional extraction. According to kinetic modeling, SSE was four-fold faster and a degradation phenomenon of polyphenols was highlighted for times longer than 10 min. The two-site kinetic model and a second order exponential decay function suitably described the extraction kinetics and degradation phase, respectively (R2 > 0.97). A remarkable effect was highlighted on the polymerization degree and galloylation percentage of proanthocyanidins by SSE, and an increase in their antioxidant activity was observed.

The Metabolic and Antioxidant Activity Profiles of Aged Greek Grape Marc Spirits.

In the last decade, "expressions" of grape marc spirits aged in wooden barrels of characteristic amber color and complex sensory attributes have been introduced. Yet studies on constituents migrating from the barrel to the beverage are scarce, and their metabolic profile remains unexplored. Furthermore, the literature on the assessment of their antioxidant activity is limited. NMR metabolomics and spectrophotometry have been implemented in 38 samples to elucidate the impact of the aging procedure on the metabolites' composition and establish whether these beverages exhibit antioxidant activity. Provenance was related to fusel alcohols, esters, acetaldehyde, methanol, saccharides, and 2-phenylethanol, while ethyl acetate and ethyl lactate contributed to discriminating samples of the same winery. Identified metabolites such as vanillin, syringaldehyde, and sinapaldehyde were related to the aging procedure. The maturation in the barrel was also associated with an increase in xylose, glucose, fructose, and arabinose. The antioxidant potential of the aged Greek grape marc spirits resulting from their maturation in oak barrels was highlighted. The metabolic profiling and antioxidant potential of aged Greek grape marc spirits were assessed for the first time. Finally, the enrichment of the aromatic region was noted with the presence of metabolites with a furanic and phenolic ring derived, respectively, from the polysaccharides' degradation or the thermal decomposition of lignin.

Vermicomposting as a Valorization Solution to the Winery Sector By-Products

Winemaking is one of the most relevant socio-economic activities in the world, particularly in countries such as Portugal, generating substantial amounts of by-products across its various phases. Managing these by-products presents significant environmental, ecological, and economic challenges. Vermicomposting, the use of earthworms to process and transform organic wastes into nutrient-rich end-products, provides a viable alternative for waste management within the wine sector. This bioprocess also produces vermicompost that enhances soil health and fosters optimal conditions for plant growth, thereby promoting resilient and sustainable viticulture practices. This review explores the various by-products produced by the vine and wine industry, highlighting the potential of vermicomposting. Remarkably, grape marc, the primary solid waste of the winemaking process, has been the most commonly vermicomposted material. In contrast, other vineyard and wine cellar by-products have been comparatively underutilized and understudied in this context. However, we hypothesize that all vine and wine industry by-products have vermicomposting potential, allowing for the production of fertilizers and soil amendments. This approach aligns with the principles of the circular economy, ensuring that all materials stemming from viticulture and wine production are valued and reused, thereby contributing to enhanced sustainability and the preservation of resources like soil.

Tetracycline (TC) removal from wastewater with activated carbon (AC) obtained from waste grape marc: activated carbon characterization and adsorption mechanism

In this study, activated carbons were obtained from grape marc for tetracycline removal from wastewater. Activated carbons were obtained by subjecting them to pyrolysis at 300, 500, and 700 °C, respectively, and the effect of pyrolysis temperature on activated carbons was investigated. The physicochemical and surface properties of the activated carbons were evaluated by SEM, FTIR, XRD, elemental analysis, N2 adsorption/desorption isothermal, thermal gravimetric (TG) and derivative thermogravimetric (DTG), and BET surface area analysis. When the BET surface areas were examined, it was found that 4.25 m2/g for activated carbon was produced at 300 °C, 44.23 m2/g for activated carbon obtained at 500 °C and 44.23 m2/g at 700 °C, which showed that the BET surface areas increased with increasing pyrolysis temperatures. The pore volumes of the synthesized activated carbons were 0.0037 cm3/g, 0.023 cm3/g, and 0.305 cm3/g for pyrolysis temperatures of 300, 500, and 700 °C, respectively, while the average pore size was found to be 8.02 nm, 9.45 nm, and 10.29 nm, respectively. A better adsorption capacity was observed due to the decrease in oxygen-rich functional groups with increasing pyrolysis temperature. It was observed that the activated carbon obtained from grape skins can easily treat hazardous wastewater containing tetracycline due to its high carbon content and surface functional groups. It was also shown that the activated carbon synthesized in this study has a higher pore volume despite its low surface area compared to the studies in the literature. Thanks to the high pore volume and surface active groups, a successful tetracycline removal was achieved.Graphical

Use of natural dyes to color metakaolin-based geopolymer materials

Over the years several colored ceramic-like materials have been prepared by using many synthetic dyes, which are toxic and polluting. Up to date, no studies have been reported on the combination of natural dyes within the geopolymers (also known as amorphous aluminosilicate polymers). In this scenario, natural dyes such as curcumin, chlorophyll, and a freeze-dried grape marc from the wine agrifood supply chain have been employed to investigate their effectiveness ability to color metakaolin-based geopolymers. The colored geopolymers, cured at 25 or 40 °C for 24 h, are characterized after 56 days of ageing time at room temperature by the ionic conductivity and pH measurements, Fourier-Transform Infrared spectroscopy, compressive strength, and color assessment by the color space analysis before and after soaking the samples in water. Eventually, the control geopolymer samples are also characterized for their potential antimicrobial and cytotoxicity properties. The main findings revealed that employing natural dyes to color geopolymers offers a promising alternative to toxic synthetic dyes. The samples retained their color for brief time when exposed to water thus suggesting indoor application. Moreover, all the samples exhibited good geopolymerization as confirmed by FTIR analysis. Notably, samples cured at 25 °C showed better compressive strengths compared to those cured at 40°C. Finally, the bioimpact of these materials suggests that the synthesis in loco of geopolymers is safe for the operator.

Application of Polarized Projective Mapping combined with Ultra Flash Profiling to a complex − high fatigue product category: The case of Greek grape marc spirits

Grape marc spirits in general and Greek grape marc spirits specifically, is an alcoholic drinks category with very limited information on its sensory properties, despite its commercial importance. Polarized Projective Mapping (PPM), a method first introduced by Ares et al. in 2013, is promising but has not been applied in combination with Ultra Flash Profiling (UFP) to sets of many and complex-high fatigue products such as spirits. Our objective was to employ UFP combined to PPM in order to profile a set of 39 grape marc spirits from Greece and relate the results to several production information of the samples such as raw materials, origin region and distillation style, and to evaluate the combination of those methods in such a category. Projective Mapping was used for pole selection and five sessions of PPM followed for the evaluation of all samples. Unlike application in previous studies we had assessors carry out the UFP task first before each PPM session. ‘Global PPM’ and ‘Global UFP’ product spaces gave 39.7% and 43.1% explained variances in the first two axes respectively, when data from all sessions and assessors were analyzed in STATIS. The biggest impact for classification of the products was from the grape varieties used as raw material, even though distillation style had a serious impact as well. Clear product clusters were obtained and combination of those methods worked well for that category. Nevertheless, there is still a need for a global method of defining the “poles” in large sample sets.

Study of the adsorption isotherm of 2-mercaptobenzothiazole by activated carbon based on grape marc: linear and non-linear method

The adsorption performance of 2-mercaptobenzothiazole from an aqueous solution on activated carbon synthesized through grape marc was explored. In this research, the agricultural waste was chemically treated with phosphoric acid (40% H3PO4, 170 °C, 3 h), then pyrolyzed at 650 °C for 2 h, to obtain the GMAC-650 to be used as an adsorbent. The resulting material was characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, and Brunauer–Emmett–Teller (BET). Maximum uptake (∼99%) is obtained under ideal conditions: an adsorbent dose of 0.8 g L−1 and pH = 8 for an initial concentration of 10 mg L−1 at 45 °C. The adsorption equilibrium data were fitted to the following isotherm models: Langmuir and Freundlich. For optimal equilibrium isotherm selection, a comparison of linear and non-linear methods for the adsorption of MBT. It was based on four error functions: the coefficient of determination R 2, the sum of squared errors, the Chi-square (χ 2), and the root mean square error. The current work has shown that the non-linear method is a more adequate method for estimating the parameters of the isotherm compared with the linear method. The comparative analysis of the models shows that the Freundlich model is more appropriate for describing equilibrium data.

Policosanols from grape marc: A new step towards a sustainable biorefinery for the wine industry by SC-CO2 extraction

Supercritical carbon dioxide (SC-CO2) extraction of policosanol (PC) from grape marc was investigated for the first time. Employing the broken plus intact cells (BIC) model (Sovová's model) the investigation focused on analyzing the SC-CO2 process to extract the nonpolar fraction from grape marc efficiently. Operating conditions for SC-CO2 extraction—280 bar pressure, 70 °C temperature, and a flow rate of 10 kgCO2/h—yielded the highest policosanol content. The extracted policosanol ranged between 3922 and 4083 mg/kgDM, constituting approximately 8 % of the total extraction yield. Surprisingly, this amount of PC was of the same order of magnitude found in beeswax yellow, a well-known rich natural source of PC. The primary aliphatic alcohols found in the PC from grape marc were hexacosanol, octacosanol, and triacontanol. These findings were consistent with grape marc samples from other Italian regions. Furthermore, a comparative analysis between SC-CO2 and Soxhlet extraction methods for PC was carried out.