1,720,976 research outputs found
Use of Hansensiaspora uvarum and managing growth conditions increase polysaccharides and antioxidants content in yeast autolysates for winemaking
Full text linkYeast derivatives are winemaking additives generally obtained from Saccharomyces spp., commonly used as fermentation and wine quality enhancers. Even though they are widely used, the production process - from initial biomass to their final composition, is not standardized and often not specific for winemaking purposes. In the present study, biomass production was performed by applying different temperatures and agitation conditions, to assess their effect on the chemical composition of the resulting derivatives, using S. cerevisiae and H. uvarum as starting microorganisms. The application of shaking mostly affected the chemical composition of yeast derivatives, resulting in the highest mean concentration of amino acids (146 mg/g in S. cerevisiae), polysaccharides (370 mg/g in H. uvarum), and glutathione (about 85 μmol/g in S. cerevisiae). Derivatives obtained from H. uvarum were characterized by a non-negligible amount of glutathione (35.6 μmol/g - 53.1 μmol/g) and cysteine (12.7 μmol/g - 26.2 μmol/g), regardless of the growth conditions previously applied; only for this strain, reducing proteins linked to cell wall residues were detected. The results obtained suggest that the chemical composition of yeast derivatives may be managed during biomass production, also using specific strains, thus possibly obtaining products naturally rich in compounds of enological interest
Improving Sustainable Viticulture and Winemaking Practices
No full textImproving Sustainable Practices in Viticulture and Enology provides an up-to-date view on the major issues concerning the sustainability of the wine supply chain. The book describes problems and solutions on the use of inputs (e.g., water, energy) and emphasizes the roles and limitations of implementing circularity in the sector. It identifies some of the most relevant metrics while pinpointing the most critical issues concerning the environmental impacts of wine’s supply chain (vineyards, wineries, trading). This is a novel reference to help the industry excel in production while improving current environmental practices. Professionals in industry, academics, environmentalists and anyone interested in gaining knowledge in sustainable solutions and practices in viticulture and wine production will find this resource indispensable
Composizione chimica ed evoluzione del profilo aromatico di spumanti Ribolla gialla prodotti con diversi metodi di rifermentazione
No full textIntensification of grape marc (Vitis vinifera) exploitation by subcritical water-ethanol extraction: Effect on polyphenol bioactivities and kinetic modelling
Full text linkSubcritical 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
Study to optimize the effectiveness of Copper treatments for a low impact viticulture
Full text linkAmong all pathologies that afflict grapevine, Downy Mildew (DM) is the most important. Generally controlled
by using Copper (Cu), recently European Commission confirmed its usage but limiting the maximum amount to 28 Kg
per hectare in 7 years (Reg. EU 2018/1981). Anyway, in the grape growing context it is difficult to reduce the use of Cu
and generally chemicals, due to climate conditions, as well as climate changing. For this instance, Cu treatments have to
be improved. Hence, the aims of this work were to determine the possibility to reduce Cu using and evaluating the
variation of Cu cladding on grapevine leaves and grapes, in relation to the phytoiatric status. The efficacy level of the Cu
protection given to DM and the correlation among them was also assessed. Five organic vineyards located in
north-eastern of Italy were selected as experimental sites. Leaves and grapes were sampled during vegetative season
and analysed for determining the quantity of elemental Cu by the use of ICP AES. Spreading of DM in vineyards was
evaluated as well and the correlation between DM and Cu quantity on leaves and grapes was determined. First results
indicate that the mean level of Cu applied by farmers (range: 3.77 to 8.88 μg/cm
2 of Cu on leaves) during vegetative
season is not enough to have an optimal protection against DM (diffusion on grapes and leaves: 40 to 50%), although at
the maximum amount of Cu, the plant protection effect was quite good. Thus, Cu treatments have to be pondered on the
basis of meteorological data and previous infection of DM, so that it will be possible to determine the right quantity of Cu
to be applied in correlation to DM presence and weather. As future goals, data will be correlated with image analysis, in
order to quickly study the best conditions for Cu application directly on field and having back a real time information of
Cu cladding and risk classes of DM infection. In this way, it is possible to reduce inputs in plant defence and then
guarantee a quality and sustainable production of grapes, wines and must
Microemulsions as delivery systems of lemon oil and β-carotene into beverages: stability test under different light conditions
Full text linkBACKGROUND: Microemulsions have been proposed as delivery systems for different lipophilic substances in transparent water-based systems. The chemical stability of the delivered compounds is a key factor to broaden the application of microemulsions in the food sector. The stability of a model beverage containing a microemulsion delivering β-carotene and lemon oil was tested under increasing light intensity up to 6000 lx at 20 °C. RESULTS: The transparent microemulsion resulted physically stable during storage indicating that no coalescence phenomenon occurred. On the contrary, both colour and flavour of the microemulsion degraded as a consequence of limonene and β-carotene oxidation. Kinetic data obtained at increasing light intensity were used to estimate the light dependence of beverage spoilage and the mathematical relationship obtained was used to predict spoilage rate under different light conditions. Finally, a shelf life predictive model was proposed. CONCLUSIONS: Transparent microemulsions can be successfully used to deliver flavoured oil and colourants into beverages. However, the photostability of the delivered compounds should be carefully studied to estimate product shelf life. To this aim, the availability of models predicting shelf life as a function of enlightening conditions could largely contribute to speed up the process
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Chitosan from mushroom by-products: sustainable extraction process and winemaking application
No full textEffect of processing Verdejo grape must by UHPH using non-Saccharomyces yeasts in the absence of SO2
No full textUltra-High Pressure Homogenization (UHPH) is an emerging non-thermal technology that can eliminate wild microorganisms from grape juice facilitating the use of non-competitive non-Saccharomyces yeast in fermentation to modulate the sensory profile. The use of UHPH processing in must from Verdejo variety grapes (Vitis vinifera L.) produces a more varietal profile reducing the contents of fermentative fruity varietal esters (−25-50%) and enhancing the release of volatile thiols (+25-75%). The aromatic profile of UHPH wines is clearly separated of controls by the aroma PCA. Additionally, the inactivation of oxidative enzymes by UHPH preserves a better color in wines with a paler yellow color and lower b* values. A better implantation of some non-Saccharomyces yeasts such as Lachancea thermotolerans can help to reduce the pH in wines from warm areas. Improved varietal aroma, paler wine color and, depending on the strain fermented with, lower pH help control the impact of global warming on wines
- …
