Les polysaccharides solubles du moût : méthode simple d'appréciation; évolution au cours de la maturation; incidence sur les opérations préfermentaires

OENO One ◽  
1981 ◽  
Vol 15 (1) ◽  
pp. 29
Author(s):  
Denis Dubourdieu ◽  
Dimitri Hadjinicolaou ◽  
Pascal Ribéreau-Gayon
Keyword(s):  
White Wine ◽  
Wine Making ◽  
Pectin Content ◽  
Juice Extraction ◽  
Grape Juices

<p style="text-align: justify;">Les polysaccharides solubles du jus de raisin sont dosés par les méthodes au phénol et au carbazol sulfuriques. Au cours de la maturation, la teneur en pectine soluble passe par un maximum, puis décroît. L'incidence de ces transformations sur les opérations préfermentaires de la vinification en blanc (pressurage et débourbage) est examinée.</p><p style="text-align: justify;">+++</p><p style="text-align: justify;">Soluble polysaccharides from grape juices are estimated with phenol-and carbazol-sulfuric methods. During the ripening, the soluble pectin content waches a maximum then decreases until maturity. The effect of these changes on the first steps of the white wine making (juice extraction and static settling) are examined.</p>

Determination of Color in White Wine and White Grape Juice Using the White Wine Colorimeter

1977 ◽  
Vol 60 (3) ◽  
pp. 739-740
Author(s):  
Herb L Wildenradt ◽  
Paul A Stafford
Keyword(s):  
Grape Juice ◽  
White Wine ◽  
Color Measurement ◽  
White Wines ◽  
Reproducible Method ◽  
Grape Juices

Abstract Further experience with the white wine colorimeter has demonstrated that this instrument provides a simple and reproducible method of color measurement for both finished and unfinished white wines and white grape juices. In view of the proven accuracy and utility of the white wine colorimeter, the method specifying this instrument, 11.B01–11.B02, has been adopted as official final action.

scholarly journals EXTRACTION OF PECTIN FROM PASSION FRUIT PEEL FOR PRODUCTION OF PECTIC OLIGOSACCHARIDES (POS)

2018 ◽  
Vol 55 (5A) ◽  
pp. 195
Author(s):  
Nguyen Thi Xuan Sam
Keyword(s):  
Quality Characteristics ◽  
Passion Fruit ◽  
Raw Material ◽  
Pathogenic Microorganisms ◽  
Fruit Peel ◽  
Yield And Quality ◽  
Pectin Content ◽  
Juice Extraction ◽  
Pectic Oligosaccharides ◽  
Optimized Conditions

Passion fruit peel obtained after juice extraction was used for extraction experiments of pectin. The effect of pH, water to peel ratio, and number of extractions, extraction time and temperature on the yield and quality characteristics of pectin were investigated. The optimized conditions for extraction of pectin frompassion fruit peel yielded 2.5 g/100 g of fresh peel.Powder pectin extracted from the fresh peels had pectin content of 95 %. The average degree of esterification of pectin was found to be 35-45 % and did not contain pathogenic microorganisms so it is suitable as a raw material for pectic oligosaccharide (POS) production 

scholarly journals Essai d'utilisation de levures sèches actives en Touraine. Contrôle de l'efficacité du levurage

OENO One ◽  
1980 ◽  
Vol 14 (1) ◽  
pp. 53
Author(s):  
Claude Cuinier ◽  
J. Lacoste
Keyword(s):  
White Wine ◽  
Species Level ◽  
Spontaneous Fermentation ◽  
Wine Making ◽  
Viable Cells ◽  
Foam Production ◽  
Level Identification

<p style="text-align: justify;">Quatre préparations de levures sèches actives ont été étudiées : nombre de cellules viables, formation de SO<sub>2</sub> production d'écume. Comparés à la fermentation spontanée, ces levains ont été employés en vinification en blanc. La dégustation n'a révélé aucune préférence entre ces vins. Mais des différences oenologiques sont apparues. Au niveau de l'espèce, l'identification des levures isolées au cours des cinq fermentations ne permet pas de conclure à l'efficacité du levurage.</p><p style="text-align: justify;">+++</p><p style="text-align: justify;">Four preparations of active dry yeasts have been studied number of viable cells, SO<sub>2</sub> formation, foam production. Compared to spontaneous fermentation, those yeasts have been used for white wine making. Tasting has not revealed any preference between those wines. But œnological differences have appeared. At species level, identification of isolated yeasts during the five fermentations does not permit to conclude in favour of yeast-adding efficiency.</p>

scholarly journals Encapsulation of Saccharomyces cerevisiae in alginate beads and its application for wine making

2018 ◽  
Vol 10 ◽  
pp. 18-23
Author(s):  
Huma Bokkhim ◽  
Praksha Neupane ◽  
Smita Gurung ◽  
Rojeena Shrestha
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Red Wine ◽  
Chemical Properties ◽  
Wine Yeast ◽  
White Wine ◽  
Molar Concentration ◽  
Soluble Solids ◽  
Yeast Saccharomyces Cerevisiae ◽  
Alcohol Production ◽  
Wine Making

A study was carried out on encapsulation of wine yeast (Saccharomyces cerevisiae) and its use in wine making compared to free yeast. Rehydrated active dry yeast was encapsulated in a 2% sodium alginate solution, cross linked with different molar concentration of CaCl2 solution (0.1, 0.2, 0.3,0.4 and 0.5M) for 30 minutes. The molar concentration with minimum cell leakage (0.2M) was used for yeast encapsulation. Colony count (CFU/ml) was analyzed for both free yeast (FY) and encapsulated yeast (EY) so as to equilibrate the rate of yeast pitching in wine fermentation. Physico-chemical properties; total soluble solids (T.S.S.), acidity and pH of red and white grapes were analyzed and were found to be 16.4±0.10oBx, 0.38±0.02% and 3.90±0.02 for white grapes and 19±0.15oBx, 0.64±0.01% and 3.1±0.10 for red grapes. During the fermentation process in both wines, a gradual reduction in T.S.S. was noted while an alternate of increase and decrease trend in acidity was noted which finally stabilized after 12 days. The final T.S.S. of wines was not significantly different for yeast types but higher values were noted for red wine (FY, 7.11±0.26 & EY, 7.33±0.19) than for white wine (FY, 6.1±0.10 & EY, 6.2±0.10). Similar trend was noted for final acidity of red wine (FY, 0.83±0.01 & EY, 0.84±0.02%). Though, no significant effect of yeast type on alcohol production was noted, the average alcohol content of red (FY, 13.22±0.26% & EY, 13.72±0.44%) and white (FY, 9.21±0.21% & EY, 9.64±0.38%) wine were found to be significantly different. However, wine prepared from EY was less turbid (Red wine, 95 NTU & White wine, 140 NTU) and had higher clarity (L*) than wine from FY. So, from this study it was concluded that encapsulating wine yeast does not affect its fermenting capability but will aid in production of less turbid wine which will definitely simplify the filtration process.

scholarly journals New White Resistant Wine Grape Cultivars from Hybrid Family Rinot x BV-7-6-2

2016 ◽  
Vol 64 (5) ◽  
pp. 1569-1573
Author(s):  
Asia Khafizova ◽  
Miloš Michlovský
Keyword(s):  
High Resistance ◽  
White Wine ◽  
Quality Level ◽  
Vitis Amurensis ◽  
Wine Quality ◽  
Cross Combination ◽  
High Quality ◽  
Resistance Level ◽  
Grape Juices ◽  
Grape Cultivars

In this study we evaluated the hybrid family Rinot x BV-7-6-2 derived from different resistance donors, such as French-American hybrids and Vitis amurensis, in Czech Republic. The objective of this breeding program was to obtain white wine cultivar of high resistance and high quality level, suitable for high density plantations and production of sparkling wines, low-alcoholic or non-alcoholic wines, grape juices and concentrates. The cross combination was performed in 2003. In this population 54 seedlings were obtained. 13 promising genotypes with high resistance level to the main fungal diseases and high grape and wine quality were selected for further investigation. Genotype Markus was found to be the most interesting and is currently under registration in national catalogue. The new resistant cultivar is suitable for integrated and organic viticulture due to significantly reduced number of pesticide applications.

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