Search Results (53)

This study evaluates the agronomic potential of two types of vermicompost—one produced solely from wine industry residues (WIR) and one incorporating sewage sludge (WIR + SS)—under rainfed and deficit irrigation conditions in Mediterranean vineyards. The vermicompost was obtained through a two-phase process involving initial thermophilic pre-composting, followed by vermicomposting using Eisenia fetida for 90 days. The conditions were optimized to ensure aerobic decomposition and maintain proper moisture levels (70–85%) and temperature control. This resulted in end products that met the legal standards required for agricultural use. However, population dynamics revealed significantly higher worm reproduction and biomass in the WIR treatment, suggesting superior substrate quality. When applied to grapevines, WIR vermicompost increased soil organic matter, nitrogen availability, and overall fertility. Under rainfed conditions, it improved vegetative growth, yield, and must quality, with increases in yeast assimilable nitrogen (YAN), sugar content, and amino acid levels comparable to those achieved using chemical fertilizers, as opposed to the no-fertilizer trial. Foliar analyses at veraison revealed stronger nutrient uptake, particularly of nitrogen and potassium, which was correlated with improved oenological parameters compared to the no-fertilizer trial. In contrast, WIR + SS compost was less favorable due to lower worm activity and elevated trace elements, despite remaining within legal limits. These results support the use of vermicompost derived solely from wine residues as a sustainable alternative to chemical fertilizers, in line with the goals of the circular economy in viticulture. Full article

Dekkera bruxellensis is already known for its great biotechnological potential, part of this due to the ability to assimilate nitrate during fermentation. Despite the previous works on nitrogen metabolism in this yeast, especially regarding nitrate assimilation, the relation between this metabolism and the TOR (Target of Rapamycin) regulatory mechanism remains unexplored. This connection may reveal key regulatory mechanisms to maximize its fermentative performance and biotechnological use. Herein, we evaluated the physiological, metabolic, and gene expression profile of D. bruxellensis GDB 248 cultivated in ammonium and nitrate as nitrogen sources in the presence of TOR complex 1 (TORC1) inhibitor rapamycin. Our results showed that inhibition of the TORC1 significantly reduces cell growth and fermentative capacity, especially in nitrate media. Gene expression analysis revealed that TORC1 plays a central role in regulating genes involved in nitrate assimilation and the adaptive performance of D. bruxellensis in fermentative environments. Therefore, the regulation of nitrate assimilatory genes YNTI, YNRI, and YNI1 responds to a nitrate-dependent mechanism as well as to a TOR-dependent mechanism. These findings expand the understanding of the regulation of nitrogen metabolism in D. bruxellensis, providing valuable information that may aid in the development of future strategies for its use as an industrial yeast. Full article

Soil degradation is caused by climate change and some agricultural practices. The use of compost from organic waste can be a sustainable solution, but poses risks to soil, crops and fruit. This article examined vineyard yield, vine and wine composition when compost from sewage sludge and urban waste was applied to two soils. One rainfed plot received 80 UFN kg/ha, while two irrigated plots received 40 and 80 UFN kg/ha. Compared to mineral fertilizer, compost increased crop yield (+60% in rainfed conditions) and above-ground biomass (+15% in rainfed conditions). Aromatic series were obtained by grouping the aroma compounds according to their aroma descriptor. In both rainfed and irrigated trials, higher values were observed in the fruity, green, waxy and floral series in wines from vines fertilized with compost compared to the control and chemical fertilization. The compounds with a higher influence in such series were ethyl butanoate, ethyl hexanoate, ethyl octanoate, hexanal, phenylacetaldehyde and 2-phenylethanol. Organoleptically, wines from compost were preferred to those from mineral fertilizer, with ratings close to the control wine, particularly in aroma, flavor and overall impression. Although further studies are needed, compost fertilization appears on the one hand to improve wine quality and, on the other hand, is a suitable alternative that reduces municipal waste. Full article

Amino acid composition and nitrogen quantification in grape must are of great importance given their usefulness for varietal characterization, influence on fermentation processes and identification of the aromatic potential of musts. The objective of this work was to determinate the amino acid and nitrogen compound profiles of 30 minority varieties of potential use in winemaking, all grown in the same ampelographic collection in Alcalá de Henares. The concentrations of 31 amino acids in must were identified and quantified using high-performance liquid chromatography (HPLC) during four seasons (2020 to 2023), and the average values of total free amino acids (TAN), yeast assimilable nitrogen (YAN) and aromatic precursor nitrogen (APN) were calculated for each variety. ‘Tazazonal’, a minority red grape variety, was found to exhibit high concentrations of yeast assimilable nitrogen (YAN), total amino nitrogen (TAN) and ammonia nitrogen (APN), comparable to those observed in ‘Tempranillo’ and ‘Garnacha Tinta’. These two cultivars are representative of traditional Spanish red grapevine varieties and are among the most widely cultivated in the country. In the case of white varieties, ‘Albillo del Pozo’, ‘Pintada’ and ‘Verdejo Serrano’ showed higher concentrations of these parameters than ‘Malvar’ and ‘Airén’, which are also widely grown in Spain. The results revealed distinct amino acid profiles for each variety, enabling their classification and supporting the identification of variants within the autochthonous germplasm. This approach aimed to highlight minority varieties of potential interest for future studies, given their relevance to both regional and national viticulture. Full article

Ten vineyards, belonging to five wine regions, were selected in this study. Maturity indicators and phenolic and aromatic compounds were measured to investigate relationships with factors related to the terroir, including climate conditions and soil nutrients. Multiple factor analysis of all compositions showed that different wine regions or vineyards had different characteristics, which were partly associated with the terroir. The results showed that Shizuishan had high sugar content. A high level of anthocyanins could be found in Qingtongxia and Yongning, respectively. Moreover, Qingtongxia had higher concentrations of monomeric phenols in grapes than the others. LSYH (Lanshanyunhao) and LL (Lilan) had higher YAN (yeast assimilable nitrogen) content and pH in grapes, but their wine had a green flavor (high concentration of alcoholic volatile compounds). The Shizuishan and Hongsipu wine regions had fruitier flavors (high concentration of ester volatile compounds). This study demonstrated the characteristics of different vineyards and wine regions, providing a direction for the future development of region-specific grapes and wines. Full article

Drama represents one of the distinct winegrape regions in the continuous growth of northern Greece. Yet, little is known about grape, must, and wine quality in various parts of the region. Determining the physicochemical characteristics of the Merlot, Cabernet Sauvignon, and Agiorgitiko grape varieties grown in different locations in the area across two vintages, their chromatic characteristics, phenolic profile, and organoleptic characteristics were the goal of this study. The results reveal a high variation in the physicochemical characteristics of must and wine among the locations. The location affects the profile of phenolic compounds with procyanidin B2, catechin, procyanidin B3, procyanidin B1, epicatechin, and gallic acid being present in high amounts. Merlot wines from the location with the highest altitude showed a higher amount of quantified phenolics. Altitude positively affected the yeast assimilable nitrogen (YAN) levels and negatively the wine’s purple hue. Moreover, the grape weight negatively affects the levels of some of the quantified phenolic compounds. On the other hand, both altitude and YAN positively impact the taste of wines. The altitude represents a significant parameter in the location studied that influences the quality parameters and taste of the wines. As part of climate adaptation strategies for viticulture in the Drama region and other comparable regions, high-altitude vineyard development should be studied to preserve the grape’s acidity and counteract warming trends. Full article

All traditional mezcal producers use artisan methods to produce mezcal. The low technological development in the elaboration processes results in low yield and high residual sugar concentration. First, this work optimized the concentration of initial sugars and yeast-assimilable nitrogen (YAN) in Agave durangensis juice fermentation at the laboratory level. A yield near 0.49 g EtOH/g sugar and a productivity of 1.54 g EtOH/L*h was obtained with an initial sugar concentration of 120 g/L and a YAN concentration of 0.227 g/L. Only Saccharomyces cerevisiae was found after 24 h of incubation at laboratory level, using MALDI-TOF identification. Agave durangensis heads crushed by the artisan process were used to test the inoculant performance. A mezcal yield of 11.6 kg agave/L of mezcal was obtained using the S cerevisiae inoculant and nitrogen addition, which was significantly different (p < 0.05) from other treatments. The population dynamics during fermentation were analyzed through isolation and identification using MALDI-TOF. Several yeast species (Pichia kluyveri, Torulaspora delbrueckii, Zygosaccharomyces bailii, and Saccharomyces cerevisiae) were found at the beginning of fermentation. Nonetheless, only S. cerevisiae was found at the end of fermentation. The implantation of the inoculant used was confirmed through the comparative analysis of amplification patterns of the GTG5 microsatellite of the strains identified as S. cerevisiae, finding that the inoculated strain proportion was greater than 80% of the yeast population. A technological alternative to increase the efficiency of the process is combining the addition of YAN and the inoculation of the native S. cerevisiae, which was isolated from artisan alcoholic fermentation of agave to produce mezcal. Full article

The adoption of sensors to monitor wine fermentation enables the collection of large datasets that relate the initial juice chemistry, density and temperature patterns during fermentation to fermentation outcomes. Wine kinetic models are now being applied to commercial fermentations in real time to identify abnormal or sluggish fermentations. In this work, 222 red wine fermentations from five harvests at two commercial wineries were evaluated by a wine fermentation model. The model parameters, initial juice chemistries and fermentation outcomes were analyzed for trends and relationships between them. While the fermentations with higher initial assimilable nitrogen concentrations had higher maximum fermentation rates, this did not guarantee successful fermentation outcomes in the tailing stage of the fermentation. Neither the initial, final, minimum and maximum temperatures, nor the initial pH, titratable acidity, measured yeast-assimilable nitrogen and primary amino nitrogen concentrations had any significant correlation with the maximum fermentation rate or successful completion of the fermentation. These results suggest that the initial juice-assimilable nitrogen measurements for these juices are of limited use in predicting slower and incomplete fermentation outcomes. Full article

Quinoa (Chenopodium quinoa) is an Andean allotetraploid pseudocereal crop with higher protein content and balanced amino acid composition in the seeds. Ammonium (NH₄⁺), a direct source of organic nitrogen assimilation, mainly transported by specific transmembrane ammonium transporters (AMTs), plays important roles in the development, yield, and quality of crops. Many AMTs and their functions have been identified in major crops; however, no systematic analyses of AMTs and their regulatory networks, which is important to increase the yield and protein accumulation in the seeds of quinoa, have been performed to date. In this study, the CqAMTs were identified, followed by the quantification of the gene expression, while the regulatory networks were predicted based on weighted gene co-expression network analysis (WGCNA), with the putative transcriptional factors (TFs) having binding sites on the promoters of CqAMTs, nitrate transporters (CqNRTs), and glutamine-synthases (CqGSs), as well as the putative TF expression being correlated with the phenotypes and activities of GSs, glutamate synthase (GOGAT), nitrite reductase (NiR), and nitrate reductase (NR) of quinoa roots. The results showed a total of 12 members of the CqAMT family with varying expressions in different organs and in the same organs at different developmental stages. Complementation expression analyses in the triple mep1/2/3 mutant of yeast showed that except for CqAMT2.2b, 11/12 CqAMTs restored the uptake of NH₄⁺ in the host yeast. CqAMT1.2a was found to mainly locate on the cell membrane, while TFs (e.g., CqNLPs, CqG2Ls, B3 TFs, CqbHLHs, CqZFs, CqMYBs, CqNF-YA/YB/YC, CqNACs, and CqWRKY) were predicted to be predominantly involved in the regulation, transportation, and assimilation of nitrogen. These results provide the functions of CqAMTs and their possible regulatory networks, which will lead to improved nitrogen use efficiency (NUE) in quinoa as well as other major crops. Full article

Protein-based clarification agents were tested to clarify Chardonnay grape musts during sedimentation. The experiments were conducted in the Etyek–Buda Wine Region in Northwest Hungary over four vintages between 2020 and 2023. The performance of the treatment agents was influenced by several factors, such as the composition of the grape must (the absolute concentration and the relative ratio of phenolic compounds) which varied with the vintage characteristics, the physiological and phenolic ripeness of the grapes, and the composition of the clarifying agents itself. Recent investigations show that fully ripe fruit juices can be clarified more effectively, and the effectiveness increases when different types of clarification agents are combined with the plant proteins, e.g., PVPP greatly facilitates the removal of phenolic compounds. The tested plant protein-based clarification agents did not influence the YAN source of the grape musts before fermentation. Our investigations proved an effective impact of these preparations even during the first steps of wine technology. Sensory properties and chemical stability are improved by decreasing the polyphenol content before fermentation, and, besides the good technological effects, wines treated with plant protein agents can be included in the vegan diet. Full article

Natural covering (NATC) has spread on hillside vineyards of central Italy as a replacement for tillage to reduce soil erosion, although it increased nitrogen and water needs. Therefore, in the current context of global warming, using cover crops (CCs) that require less water and provide nitrogen becomes crucial. The effects of two low-competition legume-enriched CCs in a rainfed hillside vineyard—a perennial legume–grass mixture (PLGM) and an annual legume cover crop of Trifolium alexandrinum (ALTA)—were compared with NATC over three years. PLGM and ALTA provided good levels of soil coverage, slightly lower than NATC, which had a negligible presence of legumes. PLGM and ALTA, due to low competition, enhanced vine vigor, resulting in thicker and wider canopies (as indicated by total leaf area and leaf layer number), higher pruning weight, and increased yield. PLGM and ALTA led to good qualitative levels, with higher grapes acidities, lower pH and total soluble solids content and, additionally, significantly higher yeast assimilable nitrogen content. In conclusion, implementing low-competition legume species in CCs is an effective tool to avoid soil erosion in a climate change scenario, leading to increased productivity, higher acidity, and improved nitrogen content in the grapes. Full article

Research into alternative vineyard practices is essential to maintain long-term viticulture sustainability. Organic mulching on the vine row improves vine cultivation properties, such as increasing soil water retention and nutrient availability. This study overviewed the effects of three organic mulches (spent mushroom compost (SMC), straw (STR), and grapevine pruning debris (GPD)) and two conventional soil practices (herbicide application (HERB) and tillage (TILL)) on grapevine physiology, agronomy, and grape quality parameters over three years. SMC mulch enhanced soil moisture and nutrient concentration. However, its mineral composition increased soil electrical conductivity (0.78 dS m⁻¹) and induced grapevine water stress due to osmotic effects without significantly affecting yield plant development. Only minor differences in leaf physiological parameters were observed during the growing season. However, straw (STR) mulch reduced water stress and increased photosynthetic capacity, resulting in higher pruning weights. Organic mulches, particularly SMC and STR, increased grape pH, potassium, malic acid, and tartaric acid levels, while reducing yeast assimilable nitrogen. The effect of organic mulching on grapevine development depends mainly on soil and mulch properties, soil water availability, and environmental conditions. This research highlights the importance of previous soil and organic mulch analysis to detect vineyard requirements and select the most appropriate soil management treatment. Full article

The aim of this study was to enhance the nitrogen supply through three different mash treatments and to investigate their effects on fermentation dynamics, yeast biomass accumulation, and the concentration of aroma-active volatiles in nitrogen-poor apple and pear mashes. In terms of nitrogen supplementation, the addition of diammonium phosphate (DAP) and amino acids (AS) accelerated fermentation and reduced the fermentation duration by 4–6 days in three out of four investigated fruit varieties. One pear variety showed sluggish fermentation, which was slightly improved by reducing the particle size (<3 mm) and significantly improved by nitrogen addition. Notably, AS supplementation resulted in a significant reduction in residual sugar concentrations and led to the highest yeast biomass accumulation across all four fruit mashes. Nitrogen supplementation significantly altered the composition of aroma-active volatiles, notably by increasing higher alcohols such as propyl alcohol, 2-methylpropanol, isoamyl alcohol, and 2-methylbutanol. The addition of AS was more effective in increasing higher alcohols, such as isoamyl alcohol and phenethyl alcohol, while decreasing the off-flavor acetaldehyde. Full article

The estimation of parameters in a wine fermentation model provides the opportunity to predict the rate and concentration outcomes, to strategically intervene to change the conditions, and to forecast the rates of heat and carbon dioxide release. The chosen parameters of the fermentation model are the initial assimilable nitrogen concentration and yeast properties (lag time, viability constant, and specific maintenance rate). This work evaluates six methods for parameter estimation: Bard, Bayesian Optimization, Particle Swarm Optimization, Differential Evolution, Genetic Evolution, and a modified Direct Grid Search technique. The benefits and drawbacks of the parameter computational methods are discussed, as well as a comparison of numerical integration methods (Euler, Runge–Kutta, backward differential formula (BDF), and Adams/BDF). A test set of density-time data for five white and five red commercial wine fermentations across vintage, grape cultivar, fermentation temperature, inoculated yeast strain, and fermentor size was used to evaluate the parameter estimation methods. A Canonical Variate Analysis shows that the estimation methods are not significantly different from each other while, in the parameter space, each of the fermentations were significantly different from each other. Full article

There is a growing market for craft beverages with unique flavors. This study aimed to obtain a palate-pleasing mead derived from Pichia kudriavzevii 4A as a monoculture. Different culture media were evaluated to compare the fermentation kinetics and final products. The crucial factors in the medium were ~200 mg L⁻¹ of yeast assimilable nitrogen and a pH of 3.5–5.0. A panel of judges favored the mead derived from Pichia kudriavzevii 4A (fermented in a medium with honey initially at 23 °Bx) over a commercial sample produced from Saccharomyces cerevisiae, considering its appearance, fruity and floral flavors (provided by esters, aldehydes, and higher alcohols), and balance between sweetness (given by the 82.91 g L⁻¹ of residual sugars) and alcohol. The present mead had an 8.57% v/v ethanol concentration, was elaborated in 28 days, and reached a maximum biomass growth (2.40 g L⁻¹) on the same fermentation day (6) that the minimum level of pH was reached. The biomass growth yield peaked at 24 and 48 h (~0.049 g g⁻¹), while the ethanol yield peaked at 24 h (1.525 ± 0.332 g g⁻¹), in both cases declining thereafter. The Gompertz model adequately describes the kinetics of sugar consumption and the generation of yeast biomass and ethanol. Pathogenic microorganisms, methanol, lead, and arsenic were absent in the mead. Thus, Pichia kudriavzevii 4A produced a safe and quality mead with probable consumer acceptance. Full article