Effect of Different Winemaking Conditions on Organic Acids Compounds of White Wines

Impact of ripeness stages on the chemical and sensory profiles of jujube wine: An analysis of physicochemical parameters, antioxidant activity, and volatile compounds

This study demonstrates that the jujube maturity significantly affects the physicochemical properties, antioxidant capacities, and volatile profiles of jujube wine. The semi-red jujube wine exhibited the highest concentrations of total phenolics (1069.73 mg GAE/L) and flavonoids (629.82 mg RE/L), underscoring potential health benefits. These levels decreased with fruit maturation, with notable decreases in catechin, chlorogenic acid, and eugenol concentrations, especially evident between the semi-red and full-red stages. Amino acid concentrations, particularly proline, increased significantly with ripeness, from 5.93 mg/L in semi-red stage to 775.91 mg/L in sweetheart stage, enhancing the wine's flavor complexity. Volatile analysis showed significant changes in the aromatic profile at the sweetheart stage, enriching the wine with fruity and floral esters. These results emphasize that the selection of optimal ripeness depends on balancing the chemical, nutritional, and sensory qualities most desired in jujube wine, providing practical guidelines for wine producers.

Effect of mixed fermentation of compound grapes on organic acids and volatiles in mulberry wine

The main objective of this study was to investigate the effect of mixed fermentation of blended grapes on the organic acid and volatile content of mulberry fruit wines before and after fermentation. Rose-scented grapes and blackberry grapes were chosen to produce fruit wines through mixed fermentation with mulberries, respectively. HPLC was employed for the content of organic acids, whereas the concentrations of volatile compounds in the mulberry wines were determined using HS-SPME-GC-MS. The results showed that yeast fermentation could effectively reduce the content of malic acid and citric acid while generating rich aroma substances. During compound grape blend fermentation, the organic acid content decreases, and more volatile compounds are produced. Among them, mulberry rosé grapefruit wine exhibits a more complex array of volatile compounds, including phenylethanol, ethyl caprylate, and ethyl caprate, alongside recently discovered compounds like isobutanol, (+)-3-methyl-2-butanol, and α-pinitol. These compounds contribute to the enhanced flavor of mulberry wine.

Revealing the flavor differences of Sauvignon Blanc wines fermented in different oak barrels and stainless-steel tanks through GC-MS, GC-IMS, electronic, and artificial sensory analyses

The fermentation vessel significantly impacts the flavor characteristics of white wine. This study provides a comprehensive flavor analysis of Sauvignon Blanc wines fermented in oak barrels and stainless-steel tanks. Wines fermented in new barrels exhibited higher levels of malic and tartaric acids compared with those fermented in old barrels or steel tanks, resulting in a more sour taste. Fermentation in oak barrels increased the content of majority phenolic compounds in wine compared to fermentation in steel tanks. GC-MS analysis revealed that the primary differential compounds present in the wines from various oak barrels and steel tanks included ethyl acetate, ethyl lactate, furfural, ethyl octanoate, isoamyl alcohol, isobutyl alcohol, 1-propanol, and acetic acid. Moreover, GC-IMS identified furan, pyrazine, acetaldehyde, and valeraldehyde in wines from oak barrels, which enhanced aromatic complexity. This study provides essential insights to promote the quality and distinctiveness of Sauvignon Blanc wines.

Effect of Organic Acid Addition Before Fermentation on the Physicochemical and Sensory Properties of Cherry Wine

Lack of acidity is the main reason for the spoilage of cherry wine, and for insufficient aroma and mouthfeel. In this study, the initial acidity of cherry purees was adjusted to 3.50, 4.15, 4.80 and 5.45 g/kg by using malic acid, lactic acid and a mixture of the two before fermentation. And the effects of different organic acid additions on the physicochemical profiles and sensory properties of cherry wines were investigated. Our findings suggest that organic acid addition can inhibit the formation of volatile acid and enhance ethanol production, while having a negative effect on their polyphenol contents. These additions can be utilized as carbon sources during cherry wine fermentation and affect its metabolism. Among them, the application of malic acid with lactic acid was shown to have more metabolically active effects on non-volatile compounds, and enhanced the total volatile organic compounds by 14.04%-66.92%. MC-4.80 and MLC-4.80 had the highest total VOC content and odor score in the sensory evaluation. However, the addition of large amounts of acids reduced the acidity score and overall acceptability of cherry wine. In conclusion, adjusting the initial acid content to 4.15 g/kg before fermentation significantly improved the quality of cherry wines, and the combination of malic acid and lactic acid was more effective for cherry winemaking. This finding evidenced that organic acid addition could be an effective strategy for improving the quality of cherry wines.

The insights into sour flavor and organic acids in alcoholic beverages

Alcoholic beverages have developed unique flavors over millennia, with sourness playing a vital role in their sensory perception and quality. Organic acids, as crucial flavor compounds, significantly impact flavor. This paper reviews the sensory attribute of sour flavor and key organic acids in alcoholic beverages. Regarding sour flavor, research methods include both static and dynamic sensory approaches and summarize the interaction of sour flavor with aroma, taste, and mouthfeel. In addition, this review focuses on identifying key organic acids, including sample extraction, chromatography, olfactometry/taste, and mass spectrometry. The key organic acids in alcoholic beverages, such as wine, Baijiu, beer, and Huangjiu, and their primary regulatory methods are discussed. Finally, future avenues for the exploration of sour flavor and organic acids by coupling machine learning, database, sensory interactions and electroencephalography are suggested. This systematic review aims to enhance understanding and serve as a reference for further in-depth studies on alcoholic beverages.

Comparison of Flavor Differences between the Juices and Wines of Four Strawberry Cultivars Using Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry and Sensory Evaluation

Fruit wine production is a practical approach for extending the shelf life and enhancing the value of strawberries (Fragaria × ananassa). Fruit cultivars and juices are important sources of volatile organic compounds (VOCs) that determine fruit wine sensory quality. In this study, VOCs in the juices and wines of four strawberry cultivars were identified using two-dimensional gas chromatography-time-of-flight mass spectrometry, and a sensory analysis of the wines was performed. A total of 1028 VOCs were detected. PCA and OPLS-DA distinguished the four cultivars from which the juices and wines were made. Six VOCs with variable importance in projection values greater than one were the main aroma and flavor components of strawberry wines. ZJ wine had the highest sensory scores for coordination (9.0) and overall evaluation (8.9) among the 18 descriptors of strawberry wine evaluated. Overall, the ZJ wine had the highest alcohol content (13.25 ± 0.59%, v/v) and sensory evaluation score, indicating that the ZJ cultivar is more suitable for fermentation. This study reflects the differences between wines made from four strawberry cultivars and provides a reference for brewing fruit wines.

Effects of Cultivar Factors on Fermentation Characteristics and Volatile Organic Components of Strawberry Wine

Strawberry wine production is a considerable approach to solve the problem of the Chinese concentrated harvesting period and the short shelf life of strawberries, but the appropriative strawberry cultivars for fermentation are still undecided. In this study, the strawberry juice and wines of four typical strawberry cultivars named Akihime (ZJ), Sweet Charlie (TCL), Snow White (BX), and Tongzhougongzhu (TZ) were thoroughly characterized for their physicochemical indicators, bioactive compounds, and volatile organic components (VOCs) to determine the optimal strawberry cultivars for winemaking. The results showed that there were significant differences in the total sugar content, pH, total acid, and other physicochemical indexes in the strawberry juice of different cultivars, which further affected the physicochemical indexes of fermented strawberry wine. Moreover, the content of polyphenols, total flavonoids, vitamin C, and color varied among the four strawberry cultivars. A total of 42 VOCs were detected in the strawberry juice and wines using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry (HS-SPME-GC-MS), and 3-methyl-1-butanol, linalool, trans-2-pinanol, hexanoic acid, and hexanoic acid ethyl ester were the differential VOCs to identify the strawberry wine samples of different cultivars. Overall, strawberry cultivar ZJ had a relatively high VOC and bioactive compound content, indicating that it is the most suitable cultivar for strawberry wine fermentation. In addition to determining the relatively superior fermentation characteristics of cultivar ZJ, the results may provide a theoretical basis for the raw material quality control and quality improvement of strawberry wine.

Effect of exogenous organic acids on chemical compositions and sensory attributes of fortified sweet wines from dehydrated grapes

In this study, acidity was regulated with the addition of exogenous tartaric acid and citric acid before bottling. The effect of exogenous organic acids on chemical compositions and sensory attributes of fortified sweet wines from dehydrated grapes were investigated. The results indicated that exogenous organic acids promoted the conversion of monomeric anthocyanins to copigmented anthocyanins in wines. Specifically, the combination of malvidin-3-O-glucoside and flavanols (catechin and epicatechin) was facilitated to form copigmented anthocyanins. Sensory analysis suggested that exogenous organic acids improved the balance of sugar and acidity and benefited the harmony in wines on the taste. Wines with a residual sugar and titratable acidity ratio of about 11:1 exhibited the more harmonious taste. In addition, it was also observed changes in the aroma profile related to volatile compounds, namely, more intense fruity aroma in wines with the addition of organic acids.

Influence of Different Types, Utilization Times, and Volumes of Aging Barrels on the Metabolite Profile of Red Wine Revealed by 1H-NMR Metabolomics Approach

It is well recognized that the aging process is a critical step in winemaking because it induces substantial chemical changes linked to the organoleptic properties and stability of the finished wines. Therefore, this study aimed to investigate the influence of different types, utilization times, and volumes of aging barrels on the metabolite profile of red wines, produced from Thai-grown Shiraz grapes, using a non-targeted proton nuclear magnetic resonance (1H-NMR) metabolomics approach. As a result, 37 non-volatile polar metabolites including alcohols, amino acids, organic acids, carbohydrates and low-molecular-weight phenolics were identified. Chemometric analysis allowed the discrimination of wine metabolite profiles associated with different types of aging containers (oak barrels vs. stainless-steel tanks), as well as the utilization times (2, 6 and >10 years old) and volumes (225, 500 and 2000 L) of the wooden barrels employed. Significant variations in the concentration of formate, fumarate, pyruvate, succinate, citrate, gallate, acetate, tyrosine, phenylalanine, histidine, γ-aminobutyrate, methionine and choline were statistically suggested as indicators accountable for the discrimination of samples aged under different conditions. These feature biomarkers could be applied to manipulate the use of aging containers to achieve the desired wine maturation profiles.

Metabolomics-Based Analyses of Dynamic Changes in Flavonoid Profiles in the Black Mulberry Winemaking Process

To overcome the fruit's perishability, mulberry wine has been developed as a method of preservation. However, dynamic changes in metabolites during mulberry wine fermentation have not been reported yet. In the present investigation, UHPLC-QE-MS/MS coupled with multivariate statistical analyses was employed to scrutinize the metabolic profiles, particularly the flavonoid profiles, throughout the process of vinification. In general, the major differential metabolites encompassed organic heterocyclic compounds, amino acids, phenylpropanoids, aromatic compounds, and carbohydrates. The contents of total sugar and alcohol play a primary role that drove the composition of amino acids, polyphenol, aromatic compound, and organic acid metabolites based on the Mantel test. Importantly, among the flavonoids, abundant in mulberry fruit, luteolin, luteolin-7-O-glucoside, (-)-epiafzelechin, eriodictyol, kaempferol, and quercetin were identified as the differential metabolic markers during blackberry wine fermentation and ripening. Flavonoid, flavone and flavonol biosynthesis were also identified to be the major metabolic pathways of flavonoids in 96 metabolic pathways. These results will provide new information on the dynamic changes in flavonoid profiles during black mulberry winemaking.