Macrowine 2021
IVES 9 IVES Conference Series 9 Extraction of pathogenesis-related proteins and phenolics in Sauvignon Blanc as affected by different

Extraction of pathogenesis-related proteins and phenolics in Sauvignon Blanc as affected by different

Abstract

The composition of wine is largely determined by the composition of pre-fermentation juice, which is influenced by extraction of grape components. Different grape harvesting and processing conditions could affect the extraction of grape components into juice. Among these grape components, pathogenesis-related (PR) proteins are of great concern for white wine maker as they are the main cause of haze formation in finished white wine. If not removed before bottling, these PR proteins may progress into haze through the formation of complex with phenolics under certain conditions. Thaumatin-like proteins (TLPs) and chitinases are the main constituents of PR proteins found in protein haze. The aim of this study was to investigate the effects of grape harvesting and processing conditions on extraction of haze-forming PR proteins and phenolics, and the consequent impact on protein stability of wine. Sauvignon Blanc grapes were harvested by hand and by machine in 2011 and 2012 in Marlborough, New Zealand. Hand harvested grapes were processed by two different treatments: whole bunch pressing without skin contact, and pressing after destemming and crushing followed by 3 h skin contact; machine harvested grapes were processed by pressing after destemming and crushing followed by 3 h skin contact. For each treatment, the juice pressing procedure was carried out by gradually increasing the pressing pressure to three different levels (0.4 MPa, 0.8 MPa and 1.6 MPa), and juice samples were collected at each pressure point and bottle-fermented separately. Results of this study showed that pressing after destemming and crushing followed by 3 h skin contact can result in greater extraction of proteins and phenolics from grapes into juice compared with whole bunch pressing. Juice and wine obtained from machine harvested grapes showed a tendency of having lower concentration of proteins, as well as, PR proteins. Juice and wine obtained from higher pressing pressure showed the highest concentration of phenolics but the lowest concentration of proteins, suggesting that proteins in grapes are easily extracted at low pressing pressure, but greater extraction of phenolics in grapes requires higher pressing pressure. Analysis of wine protein stability showed a linear correlation between bentonite requirement and the concentration of chitinases in wine, indicating the importance of removal of chitinases to achieve protein stabilization. The findings presented here contribute to an improved understanding of the variable concentration of haze-forming PR proteins in juice as affected by grape harvesting and processing conditions, and hence the variation in bentonite requirement for resultant wine.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Article

Authors

Bin Tian*, Claire Grose, James Morton, Marlene Jaspers, Mike Trought, Roland Harrison

*Lincoln University

Contact the author

Tags

IVES Conference Series | Macrowine | Macrowine 2016

Citation

Related articles…

Impact of heating must before fermentation on Chardonnay wines

Prefermentation steps of white winemaking are very important for controlling the stability and the sensory attributes of wines. Usually musts are clarified by cold settling to prevent the start of the fermentation, before racking big lees and thus limiting the appearance of vegetable or reduction off flavour while favouring an aromatic expression with low turbidity. Besides, to reach the protein stability, some white wines further require a bentonite fining, sometimes associated with negative effects on the sensory quality. This study aims to know the impact of musts heating after pressing on a Chardonnay wine in northern conditions by comparison with a classic cold racking of the must.

The influence of soil management practices on functional traits and biodiversity of weed communities in Swiss vineyards

Green cover in vine rows provides many ecological services, but can also negatively impact the crop, depending on the weed species. The composition of a vineyard weed community is influenced by many parameters. Ensuring an evolution of the vine row flora into a desired direction is therefore very complex. A key step towards this goal is to know which factors influence the establishment of the weed community and which types of communities are best suited for vineyards. In this study, we analysed the weed communities of several vineyards in the Lake Geneva region (379 botanical surveys on 117 plots), with the aim to highlight the links between soil management practices (chemical and mechanical weeding, mowing, mulching roll) and phytosociological profiles, biodiversity and selected functional traits (growth forms, life strategies, root depth). T

Ageing of Sauvignon Blanc white wines with Specific Inactivated Dry Yeasts: Effect on physical and chemical characteristics

Del Barrio-Galán, R.a, b, Gómez-Parrini, A.a, Peña-Neira, A.b a Lallemand Inc. Chile y Compañía Limitada, Rosario Norte 407, piso 6, Las condes, Santiago, Chile b Department of Agro-Industry and Enology, Faculty of Agronomical Sciences, University of Chile, Post Office Box 1004, Santa Rosa 11315, La Pintana, Santiago, Chile It is well known that polysaccharides, mainly mannoproteins, play an important role on physical, chemical and sensory quality of wines. The ageing of white wines on lees is used in order to release higher amounts of polysaccharides by the autolytic processes in order to obtain higher-quality wines. However, this technique is too slow, because the temperature and pH conditions are not the most suitable for this process. In addition, it can also involve certain disadvantages such as a greater demand on winery resources, a longer period of wine storage, the appearance of reduction notes and some microbiological alterations.

Evaluation of Polarized Projective Mapping as a possible tool for attributing South African Chenin blanc dry wine styles

Multiple Factor Analysis (MFA) According to the Chenin blanc Association of South Africa, there are three recognized dry wine styles, Fresh and Fruity (FF), Rich and Ripe Unwooded (RRU), and Rich and Ripe Wooded (RRW), classically attributed with the help of sensory evaluation. One of the “rapid methods” has drawn our attention for the purpose of simplifying and making style attribution for large sample sets, evaluated during different sessions, more robust. Polarized Projective Mapping (PPM) is a hybrid of Projective Mapping (PM) and Polarised Sensory Positioning (PSP). It is a reference-based method in which poles
(references) are used for the evaluation of similarities and dissimilarities between samples.

Testing the effectiveness of Cell-Wall material from grape pomace as fining agent for red wines

Lately several works highlighted the capacity of grape cell-wall material (CWM) to interact with proanthocyanidins (PA), indicating its potential use as fining agent for red wines.1–4 However, those studies were performed by using purified PAs and very high doses of CWM (almost ten-fold higher than those used in wine industry for other commercial fining agents). The present study focuses on the applicability of CWM from Cabernet sauvignon pomace as fining agent for red wines under real winery conditions. Grapes of cultivar Cabernet sauvignon were harvested at three different maturity levels
(unripe, mature, and overripe) and used for red winemaking. The pomace of such vinifications were used as source of CWM, and applied into red wines at two different concentrations: 0.2 g/L and 2.5 g/L.