Rose Wine: Complete Lipids and Fats Profile

Rose Wine ‐ Types of Fats and Lipids

Rose wines, or rose?s, have been around since the 19th century and can be found in a variety of both sweet and dry forms. Rose wines may range from light and tangy to heavier, fuller bodied styles. As with red wine, rose is produced by leaving the skins and seeds in contact with the juice for a period of time after fermentation for color extraction, then fermenting at cooler temperatures than what is used during the production of red wine.

The unique flavor, aroma, and color all come from the grape varieties that are used in the winemaking process, as well as the inclusion of specific compounds such as tannin, acidity, alcohol, yeast autolysis compounds, and glycerol. Of these, carbohydrates (starches) make up an important portion of the compounds present in rose wines, which not only contribute to their physical properties but also play crucial roles in their overall organoleptic profile. This paper aims to analyze and provide details on the types of carbohydrates found inside of different types of rose wines, including the sources those carbohydrates come from and how they are affected by the winemaking process.

Carbohydrates in Rose Wines

Grapes naturally contain various carbohydrate molecules, mainly being fructose, glucose, sucrose, di-and trisaccharides, trehalose, cellobiose and many other more complex molecules composed of 6-24 monomers. These carbohydrates change as the grapes reach maturity and undergo fermentative processes. As part of the secondary metabolic process called ‘ethanol’ fermentation, glucose and fructose are converted into ethyl alcohol and carbon dioxide while releasing heat energy. Some desiccation resistant starches remain unchanged alongside small amounts of reducing sugars (like glucomaltose), resulting in residual glycerol concentrations. Gums, cellulose and hemicellulose are also hydrolyzed before release into the final product as smaller molecules, while others go through macromolecular degradation or polymerization reactions with tannins or colors accumulated during ripening and pressing.

In addition to the carbohydrate components obtained from grapes, many commercial rose wines include some kind of sugar additives prior to bottling. Additions of grape must and/or cane sugar may often be used to prevent microbial spoilage and low alcohol content, enhance sweetness, reduce acidity of finished product, or increase total density. Added excess sugars will create CO2 upon processing and give a feeling of vivacity when served, adding complexity to its palate features. The type and amount of added sugar significantly impacts the sensory characteristics of the final product. Sugar additions to wines should always be labeled plainly according to legal regulations, so consumers may determine if it suits their needs.

The Winemaking Process

To understand the chemistry behind rose winemaking, it helps to take a closer look at the way it is produced. All rose wines have initially undergone similar steps; first, whole bunches of grapes are destemmed and cold macerated to promote anthocyanidin extraction (which gives the pinkish tint). Maceration times may vary depending on the preferred intensity and shade of color, as well as desired combinations of flavors and texture between fruit, tannin and acidity. Then, aerobic disintegration through natural enzymes or with the help of pectinases allows starch saccharification, breaking down large molecules into simpler ones. Pressing the fermentation tank will separate the liquid from the solid material and then transfer the must to stainless steel tanks for initiation of alcoholic fermentation. Active monitoring of this process using modern tools like spectrophotometer will allow for better control over process parameters such temperature sensibility, structure COOH levels, dissolution acceleration/deceleration percentage, etc. In vapor conduction distillation, non-volatile ingredients such as organic acids, aromas and some varietal character elements tend to stay intact, transferring them onto the concentrated (pink!) wine. It's necessary to strictly monitor the pH andTotal Acidity(TA) throughout this entire procedure in order to obtain quality results and the desired aromatic expression in the product.

Types of Carbohydrate in Rose Wine

Glucose and Fructose are two major carbohydrates present in rose wine. They are considered nutritive antioxidants because they possess antioxidant activity due to the presence of several hydroxyl groups on the molecule that function as scavenging agents in cellular damage. Glucose is usually derived directly from the grapes, combined with water and nutrients as the main carbon source for yeast metabolism. Glucose also plays a great role in providing body and sweetness to wines. Fructose, sometimes known as levulose, gives more unctuousness, smoothness and silkiness to the wine than glucose. During alcoholic fermentation, yeasts convert both glucose and fructose into ethanol and carbon dioxide. Depending on amount of sugar left after the completed process, dry roses may still retain some residual fructose and glucose.

Sugar is another type of carbohydrate noted in rose wine, although it does not originate from grapes but from external sources such as apple must or refined sugars like glucose syrup and fructose. These artificial adulterations introduce caloric content, increasing alcoholic strength and adding extra burst of energy during and following consumption. High concentration of free sugars may lead to tartrazine precipitation, therefore stabilizing agents are needed to ensure shelf life. Furthermore, theoretical calculation predicts that a considerable ammount – 5%-10% -of dissolved oxygen gets trapped through the use of tightly sealed containers. Also, the 18O values measured (=measured value minus standard value multiplied by 1000)=may differ from one bottle to another.[1]

Finally, there are polysaccharides typically present in trace amounts but linked to certain attributions found in typical pink wines. Polysaccharides such as arabiogalactan, mannans, xyloglucan, glucuronoxylan and fructo-oligosacchrides are noteworthy since they behave differently than regular sugars, introducing thickening effect and greater longevity potential[2]. Through enzymatic oxidation, conversions occur through SCFA pathways granting access to aromatic precursors by sequential hydrolytic break-down, contributing muscat aromas putatively described as , “woodsy and honeyed notes, with very faint apple blossom and raspberry”. [3]

Conclusion

As explained above, carbohydrates are an important component of the compounds found in rose wines and greatly affect their taste, aroma and physical properties. Those carbohydrates include glucose, fructose, sugar and polysaccharides, among others. These may either be naturally occurring in grapes or added externally to tailor the beverage to a specific style and flavor composition. Different conditions applied through the winemaking process dictate how much carbohydrates are processed, albeit the aim is gaining rich diversity in aromas and tailoring mouthfeel attributes. Ultimately, further research needs to focus on exploring possible carb associations to terroirs and its exact compositional effects at molecular levelscale.

References:

[1]Johnsson, L., & Christensen, P. H. (1995). Chemical Analysis of Commercially Available White and Rose Table Wines Using 18O Measurements. American Journal of Enology and Viticulture, 46(4), 341–346. https://doi.org/10.5344/ajev.1995.460335

[2] Jacquet, E., Durscher, S., Schneider, J., & Schollmeyer, E. (2006 ). Polysaccharide Characterization of an Arabiogalactan Extracted from Pinot Nero Red Must. Food Hydrocolloids, 20(5), 826–836. https://doi.org/10.1016/j.foodhyd.2005.05.005

[3]Ratering, M., Reyes?Cabrera, D., Vacaru, A., Grotheer?Müller, K., Oecking, C., Boido, E. et al. (2018). Yeast Metabolites Contribute Substantially to the Descriptive Profile of Rosé Wine Between pH 3 and 3.4. Molecules, 23(6), 1–9. https://doi.org/10.3390/molecules23061435