Fourier Spectral Deconvolution to Describe Behaviors of pH-Dependent Monomeric and Self-Associated Anthocyanin Species.

Anthocyanins are pigmented polyphenolic compounds that influence the color, stability, and quality of numerous plant organs (e.g., fruit, flowers) and their derived products (e.

Nonlinearity and anthocyanin colour expression: A mathematical analysis of anthocyanin association kinetics and equilibria.

Anthocyanins are polyphenolic compounds that provide pigmentation in plants as reflected by pH-dependent structural transformations between the red flavylium cation, purple quinonoidal base, blue quinonoidal anion, colourless hemiketal, and pale yellow chalcone species. Thermodynamically stable conditions of hydrated plant cell vacuoles in vivo correspond to the colourless hemiketal, yet anthocyanin colour expression appears in an important variety of hues within plant organs such as flowers and fruit. Moreover, anthocyanin colour from grape berries is significant in red winemaking processes as it plays a crucial role in determining red wine quality.

Chemical and Sensory Impacts of Accentuated Cut Edges (ACE) Grape Must Polyphenol Extraction Technique on Shiraz Wines.

Accentuated Cut Edges (ACE) is a recently developed grape must extraction technique, which mechanically breaks grape skins into small fragments but maintains seed integrity. This study was the first to elucidate the effect of ACE on Shiraz wine's basic chemical composition, colour, phenolic compounds, polysaccharides and sensory profiles. A further aim was to investigate any potential influence provided by ACE on the pre-fermentation water addition to must.

Processes and purposes of extraction of grape components during winemaking: current state and perspectives.

The quality of red wine is dependent on the presence not only of volatile compounds that influence wine aroma but also on phenolic compounds due to their impact on mouthfeel, colour, flavour and ageing potential. Whereas wine aroma arises from the grapes, action of microorganisms and maturation phenomena, red wine phenolics are predominantly found in the grape berry skins and seeds and are extracted during maceration into the fermenting must (i.e.

Potato Protein Fining of Phenolic Compounds in Red Wine: A Study of the Kinetics and the Impact of Wine Matrix Components and Physical Factors.

Producing wines within an acceptable range of astringency is important for quality and consumer acceptance. Astringency can be modified by fining during the winemaking process and the use of vegetable proteins (especially potato proteins) as fining agents has gained increasing interest due to consumers' requirements. The research presented was the first to investigate the effect of a potato protein dose on the kinetics of tannin and phenolic removal compared to gelatin for two unfined Cabernet Sauvignon wines.

Mathematical modelling of anthocyanin mass transfer to predict extraction in simulated red wine fermentation scenarios.

Anthocyanins are polyphenolic compounds present in grapes that are responsible for the initial colour of red wine and their incorporation into derived pigments leads to long term colour stability. The ability to predict the effect of process variables, either controlled by winemakers or that naturally change throughout fermentation, on the extraction of anthocyanins is vital to producing red wine of high quality. A 2 factorial experiment with additional points located at central factor conditions was used to determine the impact of temperature, sugar and ethanol concentrations on the mass transfer properties of anthocyanins from fresh Pinot noir grape solids.

Dynamic characterization of wine astringency profiles using modified progressive profiling.

Wine astringency is important for quality and consumer acceptance. Perception of this mouthfeel is temporal and can be separated further into unique textural sub-qualities. Quantitative data on these astringent sub-qualities in wine however are poorly understood.

Mass Transfer of Anthocyanins during Extraction from Pre-Fermentative Grape Solids under Simulated Fermentation Conditions: Effect of Convective Conditions.

The colour of red wine is largely determined by the concentration of anthocyanins that are extracted from grape skins during fermentation. Because colour is a key parameter in determining the overall quality of the finished product, understanding the effect of processing variables on anthocyanin extraction is critical for producing a red wine with the desired sensorial characteristics. In this study, the effect of convective conditions (natural and forced) on the mass transfer properties of malvidin-3-glucoside (M3G) from pre-fermentative grape solids was explored at various liquid phase conditions representing stages of fermentation.

Modelling the Mass Transfer Process of Malvidin-3-Glucoside during Simulated Extraction from Fresh Grape Solids under Wine-Like Conditions.

Extraction of grape components is a key consideration for red winemaking. The impact of changing process variables on mass transfer properties of anthocyanins from fresh pre-fermentative red grape solids under forced convective conditions was explored using the dominant red grape anthocyanin, malvidin-3-glucoside (M3G) as a model solute. A two level full factorial design was implemented to investigate effects of temperature, sugar and ethanol on mass transfer properties.

Sustainable wineries through waste valorisation: A review of grape marc utilisation for value-added products.

Grapes are one of the most cultivated fruits worldwide, with one third of total production used in winemaking. Both red and white winemaking processes result in substantial quantities of solid organic waste, such as grape marc (pomace) and stalks, which requires suitable disposal. Grape marc accounts for approximately 10-30% of the mass of grapes crushed and contains unfermented sugars, alcohol, polyphenols, tannins, pigments, and other valuable products.

Degradation of white wine haze proteins by Aspergillopepsin I and II during juice flash pasteurization.

Bentonite is commonly used to remove grape proteins responsible for haze formation in white wines. Proteases potentially represent an alternative to bentonite, but so far none has shown satisfactory activity under winemaking conditions. A promising candidate is AGP, a mixture of Aspergillopepsins I and II.