Effect of Cold Stabilization Duration on Organic Acids and Aroma Compounds during Vitis vinifera L. cv. Riesling Wine Bottle Storage

Research progress of tartaric acid stabilization on wine characteristics

Tartaric acid is one of the characteristic acids in wine, playing a crucial role in wine characteristics. However, superabundant tartaric acid will form insoluble salts and precipitate in the form of crystals, affecting consumers' purchasing appetite. Therefore, tartaric stability is also one of the important indices for controlling the wine quality. At present, the main processing methods for tartaric stability include cold stabilization, ion exchange treatment, electrodialysis and the addition of exogenous components (gum arabic, metatartaric acid, carboxymethyl cellulose, mannoprotein and potassium polyaspartate). This review summarizes and analyzes the origin of tartaric acid in wine, factors influencing the tartaric stability, detection methods, treatments for tartaric stabilization, and the effects of these methods on the sensory quality of wine. Comparing the effects of these methods on wine quality can provide a basis for the further study of tartaric stabilization methods in order to select an appropriate tartaric stabilization method.

Wine Volatilome as Affected by Tartaric Stabilization Treatments: Cold Stabilization, Carboxymethylcellulose and Metatartaric Acid

The primary cause of bottled wine sediment is tartrate crystal precipitation. To prevent this, wines undergo a stabilization process before bottling. The most commonly used method is cold stabilization, which induces the precipitation of tartrate crystals that are then removed, thereby eliminating the excess ions that cause instability in wine. Another approach to tartaric stabilization is using enological stabilizers with a colloid protective effect, which prevents the formation of tartrate crystals. The most commonly used tartaric stabilizers are sodium carboxymethylcellulose (CMC) and metatartaric acid. However, both have drawbacks: they are semi-synthetic products, and metatartaric acid degrades over time, losing its stabilizing effect. This study aims to compare the effects of cold stabilization, stabilization with CMC, and metatartaric acid on the chemical composition, particularly the volatilome, of white, rosé, and red wines. Cold stabilization significantly impacted the wine volatilome, especially in white and rosé wines, by decreasing total alcohols and increasing total esters. It also reduced the color intensity of rosé and red wines by lowering monomeric anthocyanins. In contrast, enological stabilizers had minimal impact on the wines' phenolic composition, chromatic characteristics, and volatilome. The sensory impact of cold stabilization is complex; it can potentially enhance the aroma of white and rosé wines by increasing ester VOCs and decreasing higher alcohols, but it negatively affects the color of rosé and red wines.

Variations in physicochemical characteristics, antioxidant activity, phenolic and volatile profiles, and sensory attributes of tea-flavored Chardonnay wine during bottle aging

A novel Chardonnay wine flavored with either green tea or black tea was subjected to bottle aging for 9 months, and the physicochemical properties, antioxidant capacity, total phenolic content, volatile content and sensory properties were monitored. There were 272 phenolic and non-phenolic compounds characterized in the aged Chardonnay wines, including newly formed 9, 1, 3 and 8 phenolic compounds and 10, 6, 1 and 6 non-phenolic compounds after aging for 1, 3, 6 and 9 months, respectively. For all the aged wines, catechin was determined as the most abundant phenolic compound, and epigallocatechin mainly contributed toward the antioxidant power. A total of 54 volatile compounds were identified in the aged Chardonnay wines, including 17 odor-active compounds. The aging process diminished floral and fruity odors, but intensified green odor. The consumer study revealed the highest consumer liking for 1% (w/v) black tea infused wine. This study revealed the quality and bioactivity of this novel flavored wine type during aging which is critical to understand the shelf-life and functionality of the product.

Effect of Encapsulation Processes by Freeze and Spray Drying on the Antioxidant Properties of Red Wine from cv. Listan Prieto and Syrah

BACKGROUND

Wine antioxidants are linked to cardiovascular disease prevention, thus are highly valued by the healthy food market. The dehydration process removes alcohol and water from wine and allows it to extend its shelf life, while encapsulation can help preserve physical-chemical and antioxidant properties. Moreover, information on the effect of wine drying and encapsulation on non-anthocyanin phenolic compounds is limited in the literature.

METHODS

Listan Prieto and Syrah (Vitis vinifera L.) wines were dehydrated and converted into powder by freezing and spray drying. Powdered wines were subjected to water activity, pH, soluble solids, color, and phenolic compounds analysis.

RESULTS

Freeze-drying process produced powdered wines with higher pH than the spray-drying process. Powdered wines made by these processes presented similar water activity and soluble solids. Powdered wines did not show statistical differences in trans-resveratrol, hydrocinnamic acids, phloretin, kaempferol, and quercetin content according to their dehydration process. In addition, powdered wines significantly concentrated hydrocinnamic acid and quercetin when compared to non-dealcoholized and dealcoholized wine samples.

CONCLUSIONS

The results suggest that the dehydration process does not negatively modify the characteristics of the wine, and it retains a significant concentration of phenolic compounds. Therefore, powdered wines have an interesting potential to be used as a natural source of antioxidants for food supplementation.