Compounds In Wine Research Articles

Investigating the impact of pedoclimatic conditions on the oenological performance of two red cultivars grown throughout southern Italy.

The cultivated grapevine, Vitis vinifera subsp. vinifera, possesses a rich biodiversity with numerous varieties. Each variety adapts differently to varying pedoclimatic conditions, which greatly influence the terroir expression of wine regions. These conditions impact vine growth, physiology, and berry composition, ultimately shaping the unique characteristics and typicity of the wines produced. Nowadays, the potential of the different adaptation capacities of grape varieties has not yet been thoroughly investigated. We addressed this issue by studying two grape varieties, Aglianico and Cabernet Sauvignon, in two different pedoclimatic conditions of Southern Italy. We evaluated and compared the effect of different pedoclimatic conditions on plant physiology, the microbial quality of grapes using Next-Generation Sequencing (NGS) technology, the expression trends of key genes in ripe berries and the concentration of phenolic compounds in grapes and wines by HPLC-MS, HPLC-DAD, NMR and spectrophotometric analyses. Metabolomic and microbiome data were integrated with quantitative gene expression analyses to examine varietal differences and plasticity of genes involved in important oenological pathways. The data collected showed that the phenotypic response of studied grapes in terms of vigor, production, and fruit quality is strongly influenced by the pedoclimatic conditions and, in particular, by soil physical properties. Furthermore, Aglianico grape variety was more influenced than the Cabernet Sauvignon by environmental conditions. In conclusion, the obtained findings not only reinforce the terroir concept and our comprehension of grape's ability to adapt to climate variations but can also have implications for the future usage of grape genetic resources.

Winemaking: “With One Stone, Two Birds”? A Holistic Review of the Bio-Functional Compounds, Applications and Health Benefits of Wine and Wineries’ By-Products

The plethora of bio-functional compounds present in fermented alcoholic beverages like wine, as well as the valorisation of bioactives from wineries’/breweries’ by-products like grape pomace and grape seed, has gained significant interest in the functional foods sector. This functional beverage, wine, has always accompanied humanity, for religion or for health, especially in the Mediterranean, while the benefits of its moderate consumption were documented even by the Greek physician Hippocrates of Kos (460–370 BC). After a big gap, an outbreak of research on wine benefits has surfaced only since the 1990s, when the term “French paradox” was introduced to the US public during a CBS show, while recent evidence has outlined that the beneficial effects of wine consumption are derived by the synergisms of its bio-functional compounds and their digestion-derived metabolites. Within this article, the proposed health benefits of moderate wine consumption, as a functional component of a balanced diet (i.e., the Mediterranean diet) against inflammation-related chronic disorders, is thoroughly reviewed. The various bio-functional compounds of both wine and wineries’ by-products, such as their bioactive phenolics, unsaturated fatty acids, polar lipids and dietary fibres, and their functional antioxidant, anti-inflammatory and antithrombotic health-promoting properties, are also thoroughly evaluated. The mechanisms of action and synergism, by which the health benefits are elicited, are also explored. Functional properties of non-alcoholic wine products are also introduced. Emphasis is also given to applications of wineries’ by-products bioactives, as ingredients of bio-functional foods, supplements and nutraceuticals. Limitations and future perspectives for this popular functional alcoholic beverage (wine) and its rich in bioactives by-products are also addressed.

The effect of prolonged (150 days) post-fermentative maceration in steel tanks and oak barrels on Cabernet Sauvignon wine quality: mathematical modelization of the phenolic compounds’ behaviour

ABSTRACT The aim of this study was to evaluate the effects of the prolonged post-fermentative maceration during the winemaking of Cabernet Sauvignon grapes in oak barrels and steel tanks and apply to this purpose a mathematical modelization to better and easily understand the dynamics and phenomena related to this process. The study focused on the time series of phenolic and volatile compounds in wines during the maceration with solid parts and residual components of the alcoholic fermentation, only for anthocyanins and non-anthocyanin flavonoids two mathematical models were proposed. The results showed that solid parts during the post-fermentative maceration phase provided a higher content of polyphenols and total flavonoids in oak barrels and steel tanks. The largest contents of polyphenols and flavonoids were observed in oak barrel trials. Among the anthocyanins in both trials, we have assisted in a decreasing trend in delphinidin-3 glucoside, cyanidin-3-glucoside, petunidin-3-glucoside and peonidin-3-glucoside, with a more accentuated process for the first two molecules in a barrique trial, also acetylated anthocyanins showed a decreasing trend more intense in the barrique trial. Post-fermentative maceration improved the sensory characteristics in terms of intensity, complexity, and persistence at both olfactory and gustatory levels, especially in oak barrel vinification.

Aging acceleration of balsamic vinegar applying micro-oxygenation technique.

The effect of micro-oxygenation (MOX) technique on quality and sensorial characteristics of balsamic vinegar was investigated, aiming to aging acceleration. Aging experiments were conducted using a multiple diffuser micro-oxygenator for up to 6months with an oxygen flow of 30mg/L/month, including oak chips (1g/L) or not. Barrel maturation was simultaneously carried out. Quality, nutritional, sensorial characteristics and the aromatic profile of all aged vinegars were evaluated throughout aging. MOX accelerated the alteration of aging indices. Volatile compounds of fruity aroma and wine were decreased, while the fatty/buttery and caramel aroma compounds were increased. Similar compounds of 1.5-year barrel maturation were developed within 6 and 5months applying MOX without or with oak chips, respectively. MOX resulted in reduction of the aging time to 1/3 compared to the corresponding one in barrels, considered as an attractive approach for vinegar-producing industries, mimicking and accelerating the long and costly barrel aging.

Kırmızı Şaraplarda Antioksidan Kapasite ile Toplam Fenolik Bileşik ve Toplam Monomerik Antosiyanin Düzeylerinin İlişkileri

Bu araştırmada üç farklı kırmızı şarabın toplam fenolik bileşik, toplam monomerik antosiyanin ve antioksidan kapasitelerinin belirlenmesi ve birbirleri ile ilişkilerinin incelenmesi amaçlanmıştır. Araştırmada fermantasyonlarını tamamlamış Merlot, Cabernet Franc, Cabernet Sauvignon şaraplarının toplam fenolik bileşik, toplam monomerik antosiyanin ve ABTS, DPPH, FRAP ve ORAC yöntemleri ile antioksidan kapasiteleri belirlenmiş, sonuçların birbirleri ile korelasyonları incelenmiştir. Kırmızı şarapların toplam fenolik bileşik düzeyleri 2874 ile 3451 mg GAE L-1, toplam monomerik antosiyanin düzeyleri 305-357 mg L-1 aralıklarında değişen seviyelerde ölçülmüştür. Antioksidan kapasite düzeylerinin sırası ile ABTS, DPPH, ORAC ve FRAP yöntemlerine göre 32.74-35.83 μmol troloksmL-1; 14.98-19.21 μmol troloks mL-1; 25.93-29.07 μmol troloks mL-1; 28.12-36.05 μmol troloksmL-1 düzeylerinde olduğu tespit edilmiştir. ORAC yöntemi dışında incelenen bütün parametreler birbirleri ile ilişkili bulunmuştur. Araştırmada incelenen kırmızı şarapların fenolik bileşik ve antioksidan kapasiteleri yüksek olmakla birlikte, antioksidan kapasite tayini amaçlı ORAC yöntemi dışındaki yöntemlerin birbirleri ile değişebilir ve karşılaştırılabilir oldukları sonucuna varılmıştır.

Phenolic Compounds in Wine

Wine is probably the most popular and oldest human beverage [...]

Convolution Neural Network-Assisted Smart Fluorescent-Tongue Based on Lanthanide Ion-Induced Forming MOF/HOF Composite for Differentiation of Flavor Compounds and Wine Identification.

Wine flavor is a vital quality characteristic in wine, influenced by those flavor components with low sensory thresholds. It is crucial to recognize and classify the wine components related to their flavor contribution. The integration of fluorescent sensors and artificial intelligence shows huge potential in flavor recognition by emulation of the gustatory perception system. Meanwhile, achieving information identification of wine based on multiple information barcodes has hopeful applications in anticounterfeiting. In this study, we present a simple method in which organic linkers are weaved into a hydrogen-bonded organic framework (HOF) for the available transformation of a metal-bonded organic framework (MOF) induced by lanthanide ions (Ln3+). The fluorescent Ln-MOF/HOF composite exhibits high sensitivity, rapid response, and good recyclability for detecting seven flavor compounds in wine, including tannic acid, ionone, vanillin, anethole, anisaldehyde, hydroxybenzaldehyde, and 4-hydroxy-2-methylacetophenone. Depending on its satisfactory detectability, a novel strategy is provided in which a fluorescent sensor is able to function as a smart fluorescent-tongue (F-tongue) by the aid of convolutional neural network to differentiate these seven flavor compounds. In addition, the Ln-MOF/HOF composite has been used to prepare multiple information barcodes for wine information identification on the basis of dynamic fluorescence response toward tannic acid. The mimetic gustatory perception system developed in this study may offer a promising strategy for flavor recognition in food and further food anticounterfeiting.

Characterization of Bioactivity of Selective Molecules in Fruit Wines by FTIR and NMR Spectroscopies, Fluorescence and Docking Calculations.

Fourier transform infrared (FTIR) and proton nuclear magnetic resonance (1H NMR) spectroscopies were applied to characterize and compare the chemical shifts in the polyphenols' regions of some fruit wines. The obtained results showed that FTIR spectra (1800-900 cm-1) and 1H NMR (δ 6.5-9.3 ppm) of different fruit wines can be used as main indices of the year of vintage and quality of fruit wines. In addition to the classical determination of antioxidant profiles and bioactive substances in wines, fluorometric measurements were used to determine the interactions of wine substances with the main human serum proteins. The results showed relatively high binding properties of wines with the highest one for pomegranate, followed by kiwifruit and persimmon wines. The interactions of vitamin C, catechin and gallic acid with human serum albumin (HSA) were also examined by docking studies. The docking calculations showed that gallic acid has a stronger binding affinity compared to catechin and vitamin C. The stronger binding affinity of gallic acid may be due to three hydrogen bonds and pi-pi interactions. The fluorescence and docking studies proved that only the bioactive compounds of wines and not the amount of alcohol have high binding properties to human serum proteins. The emphasis in this report was made on the utility of FTIR, NMR and fluorescence of wines as a mean of wine authentication and its fingerprint. The findings, based on polyphenols from fruits and fruit wines, their bioactivity and health properties, offer valuable insights for future endeavours focused on designing healthy food products.

Retention of Phthalates in Wine Using Nanomaterials as Chemically Modified Clays with H20, H30, H40 Boltron Dendrimers.

The presence of phthalic acid esters in wines presents a major risk to human health due to their very toxic metabolism. In this paper, aluminosilicate materials were used, with the aim of retaining various pollutants and unwanted compounds in wine. The pollutants tested were di-butyl and di-ethyl hexyl phthalates. They were tested and detected using the gas chromatography-mass spectrometry (CG-MS) analytical technique. Nanomaterials were prepared using sodium bentonite, and were chemically modified via impregnation using three types of Boltron dendrimers of second, third and fourth generations (NBtH20, NBtH30 and NBtH40). The synthesized nanomaterials were characterized using the Brunauer-Emmett-Teller (BET) method, Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. In this paper, two aspects were addressed: the first related to the retention of phthalate-type pollutants (phthalic acid esters-PAEs) and the second related to the protein and polyphenol levels in the white wine of the Aligoté grape variety. The results obtained in this study have a major impact on PAEs in wine, especially after treatment with NBtH30 and NBtH40 (volumes of 250-500 μL/10 mL wine), with the retention of the pollutants being up to 85%.

Malolactic fermentation performance of indigenous Oenococcus oeni strains from Shaanxi wine region (China) and their mutants on Pinot Noir and Chardonnay wines

This study investigated the malolactic fermentation (MLF) performance of three indigenous Oenococcus oeni strains isolated from the Shaanxi wine region (China) and mutants of those strains with different acid-tolerant phenotypes on Pinot Noir and Chardonnay wines. The MLF kinetics of these strains, as well as the basic chemical parameters and volatile compounds of wines after MLF, were determined. All strains successfully completed MLF in Pinot Noir wines with a pH of 3.45; however, only the acid-tolerant mutants were able to complete MLF in Chardonnay wines with a pH of 3.2. Compared with other strains, inoculation with the acid-tolerant mutants reduced the MLF duration up to 4.5 days in Pinot Noir wines, and significantly increased the concentrations of total volatile compounds in Pinot Noir wines and Chardonnay wines, with values rising from 324226.38 to 361450.91 μg/L and from 213322.96 to 279848.12 μg/L, respectively. These wines had higher levels of 2,3-butanediol, linalool, α-terpineol and β-damascenone, contributing to more pronounced butter and floral aroma profiles. MLF performance of these strains was positively correlated with their acid tolerance, and indigenous acid-tolerant mutants show great potential to be developed as MLF starters, contributing to the regional characteristics and high quality of wines.

Effects of Torulaspora delbrueckii on physicochemical properties and volatile flavor compounds of navel orange wine

Effects of Torulaspora delbrueckii on physicochemical properties and volatile flavor compounds of navel orange wine

Paper chromatography approach for the assessment of interaction between red wine and whole saliva

In-mouth interaction of red wine compounds with salivary proteins is a primary event allegedly responsible for eliciting the mouth-feel sensation of astringency. Those interactions have been currently associated with precipitation of salivary protein/polyphenol complexes. However, such single physicochemical evidence for interaction does not account for the complexity of astringency. This study aimed to develop a paper chromatography method to assess interactions between red wine and the salivary protein fraction using stepwise series of red wine/saliva binary mixtures from 100% wine to 100% saliva (“Alpha and Omega series”). Aliquots of each one of the mixtures were spotted on a cellulose membrane to scrutinize independently the distribution areas of wine components (naturally pink-colored) and salivary protein (stained blue in Coomassie Brilliant R-250). This double target detection revealed interactions between saliva and red wine components along most of the quantitative Alpha and Omega series, a point of equivalence corresponding to maximum interactivity for both complex reactants and a non-diffusible sub-fraction of saliva displaying the highest interactivity. The results indicate a novel way to assess quantitatively physicochemical interactions between red wines and human saliva but also provide new lights to approach the identification of molecular salivary structures involved in triggering astringency.

Comparison of phenolic profiles of albino bilberry (Vaccinium myrtillus L.) wines fermented by non-Saccharomyces yeasts

The profiles of phenolic compounds in albino bilberry (Vaccinium myrtillus L.) juice and wines fermented with eight different non-Saccharomyces yeasts, including Torulaspora (Tr.) delbrueckii, Issatchenkia (Is.) orientalis, Lachancea (Lc.) thermotolerans, Saccharomycodes (Sd.) ludwigii, Hanseniaspora (Hs.) uvarum, Metschnikowia (Mt.) pulcherrima, Pachysolen (Pc.) tannophilus, and Schizosaccharomyces (Sz.) pombe, were assessed using UHPLC-QTOF-MS and UHPLC-DAD. A total of 40 phenolic compounds, including 20 phenolic acids, 16 flavonols, and 4 flavan-3-ols, were identified and quantified in the albino bilberry products. In unfermented juice, phenolic acids were the most predominant group, accounting for 80.5% of total phenolics. After fermentation, the concentrations of phenolic acids, flavonols, and flavan-3-ols showed significant increases by 21.8%–42.5%, 26.8%–47.2%, and 4.9%–74.5%, respectively. Five new flavonols including myricetin-3-O-glucoside, kaempferol-3-O-galactoside, laricitrin-3-O-galactoside, isorhamnetin-3-O-galactoside, and syringetin aglycone, which were absent in the albino bilberry juice, were formed during fermentation mainly by the metabolism of non-Saccharomyces yeasts. The phenolic compositions of albino bilberry wines depended primarily on the applied yeasts. Most of the non-Saccharomyces yeasts showed positive contributions to the increase of phenolic compounds except for Pc. tannophilus PT70352, which reduced the total phenolic content reflecting the decreases in concentrations of phenolic acids and flavan-3-ols, especially of p-coumaroyl monotropeins, procyanidin B-type dimers, and (−)-epicatechin. The highest levels of phenolic acids and flavan-3-ols were detected in the sample fermented by Hs. uvarum HU26650. The fermentations with Sd. ludwigii SL3447, Tr. delbrueckii TD291, and Mt. pulcherrima MP70321 were characterized by higher concentrations of myricetin-3-O-glucoside and syringetin-3-O-glucoside but lower contents of most phenolic acids.

The Effects of Ultrasonic and Gamma Irradiation on the Flavor of Potato Wines Investigated by Sensory Omics.

Aroma is one of the most fascinating and least-known mysteries of Baijiu research. The volatile compounds (VOCs) of potato wine were evaluated by sensory omics techniques in order to comprehend their overall flavor characteristics and investigate the effects of ultrasonic treatment and gamma irradiation therapy on the aroma of the wine. The findings revealed that a total of 14 flavor compounds were identified by GC-MS. Isoamyl alcohol, ethyl octanoate, and 1,1-diethoxyethane were the key aroma components, according to GC-O analysis. A total of 50 volatile substances were identified by GC-IMS. After being subjected to irradiation and ultrasonic treatment, the alcohol level of the potato wine reduced while the esters content increased. By calculating the relative odor activity value, a total of 29 aroma components were classified as key aroma compounds (ROAV > 1). According to the results of the sensory evaluation-fruity, Fen-flavor, and sweet-and the acceptability of the irradiated and ultrasonicated potato wine were improved. Therefore, the use of ultrasonic and irradiation therapy in potato wine, as well as the overall aroma building of potato wine, can be supported theoretically by this study.

The Influence of Sulfur Dioxide Concentration on Antioxidant Activity, Total Polyphenols, Flavonoid Content and Individual Polyphenolic Compounds in White Wines during Storage

Wines represent a rich source of bioactive compounds, especially polyphenolic compounds, which mostly contribute to the antioxidant activity. Sulfur dioxide (SO2) has mostly been used as a preservative in winemaking to prevent oxidation during storage. The aim of this paper is to evaluate the changes in SO2 levels and the influence of sulfur dioxide addition at seven different concentrations on the antioxidant activity (detected by DPPH-2,2-diphenyl-1-picrylhydrazyl and the ABTS Trolox equivalent antioxidant capacity methods), total polyphenols, flavonoid content and individual polyphenolic compounds (determined by the HPLC high-performance liquid chromatography method) of white wines during 5 months of storage. The assayed sulfur dioxide concentrations show a decreasing tendency with time, with a final decrease of more than 50% in comparison with the start of the experiment. Between the first and second measurements, the average decrease in sulfur dioxide was 16%. In the following interval, it was found that the maximum decline in SO2 was 26%. The changes in SO2 levels cannot be considered statistically significant. At the same time, we observed a decreasing tendency in the TPC content during storage. The antioxidant activity determined by the DPPH method at the beginning of the experiment ranged from 116.75 up to 270.62 mg·L−1, while the antioxidant activity increased with sulfur dioxide concentration. The AA detected by the ABTS method displayed a decreasing tendency during storage. In the case of the TFC content, we observed a significant influence of sulfur dioxide on the concentration. No addition or addition of high SO2 concentrations negatively influenced the flavonoid content in the samples. During storage, we observed a highly variable content of phenolic compounds in relation to SO2 addition. The most abundant compounds were chlorogenic acid, caffeic acid and epigallocatechin.

Wine Polyphenol Content during the Fermentation of Vitis vinifera CS Grapes and Its Relationship with the Presence of Minerals in the Resulting Wine

The content of minerals and bioactive compounds in wine depends on various factors, among which are the origin of the grapes, their phenolic composition, and the winemaking process. This study monitored the physicochemical parameters, phenolic compound contents, and antioxidant capacity of the red grape Vitis vinifera L. “Cabernet Sauvignon” harvested in three Mexican vineyards during the first nine days of the fermentation process. The bioactive compounds and elemental composition (determined by inductively coupled plasma–optical emission spectrometry, ICP-OES) were correlated. The fermentation process decreased from 22 to 5 °Bx in all cases, while the acidity increased from 6.5 to 8 g of tartaric acid/L, decreasing the pH. The phenolic compounds extracted during the winemaking ranged from 1400 to 1600 gallic acid equivalent/L, while the antioxidant capacity was 9 mmol Trolox equivalent. The bioactive compounds identified by HPLC were resveratrol, piceid, catechin, and epicatechin. The presence of Na, Mg, and Fe was correlated with antioxidant capacity, while higher Mn, Pb, Zn, and Cu contents were related to the presence of resveratrol, piceid, and catechin in Cabernet Sauvignon wine. Thus, certain minerals present in the soil that were transferred to the V. vinifera grapes can influence the amount and type of bioactive compounds present in the wine. The phenolic content and, therefore, the organoleptic characteristics of the wine are related to the mineral composition of the vine-growing soil (origin).

Effects of winemaking techniques on the phenolics, organic acids, and volatile compounds of Muscat wines

This study aimed to investigate the impact of various winemaking techniques on the phenolic, organic acid and aroma compound profiles, as well as sensory characteristics of different Muscat wines including dry white wine (DWW), orange wine (OW), rose wine (RW), semi-sweet wine (SW), sweet white wine (SWW), 3% vol wine (3%W), 5% vol wine (5%W), 7% vol wine (7%W), fortified wine (FW) and distilled wine(DW). A total of 14 individual phenolics, 11 organic acids were performed by HPLC and 33 volatile compounds were determined by GC-MS. The highest contents of individual phenolics, organic acids, and aroma compounds were found in DWW, SWW, and SW, respectively, while DW contained the lowest quantities. Sensory analysis showed that 7%W and SWW performed well in terms of overall quality. This study laid a foundation for optimizing the process of winemaking so that the wine products meet the needs of consumers by retaining the characteristics of rose aroma grape varieties.

Migration of polyphenols from natural and microagglomerated cork stoppers to hydroalcoholic solutions and their sensory impact

During bottling aging, the wine comes into contact with the cork stopper due to the horizontal position of the bottle. The release of compounds, such as cork phenolic compounds, thus take place between the cork and the wine, depending on the type of cork stopper and the surface treatments applied. Many publications describe the extraction of these phenolic compounds in wine or hydroalcoholic solutions from natural corks, but few address microagglomerated corks, which are increasingly used by winemakers to seal their bottles. The aim of this study was therefore to compare the polyphenols, mainly hydrolysable tannins, transferred from natural and microagglomerated corks treated with supercritical CO2 into hydroalcoholic solutions. For this purpose, polyphenols released in macerates of natural and microagglomerated cork stoppers were identified and quantified by HPLC-DAD-ESI-QQQ. Suberic acid was also quantified. In this study, despite the high intra-“natural cork stopper” variability, significant differences were found between both types of stoppers for all polyphenols, the agglomerated corks releasing significantly less polyphenols; i.e., 25 times less. In contrast, suberic acid was extracted from both types of corks in similar concentrations; therefore, its extractability was not impacted by the type of stopper. A sensory profile was also carried out on the macerates. Macerates of natural cork stoppers were perceived with notes of “cardboard, dust, plank, wood” and “cork taint” significantly higher than supercritical CO2 treated microagglomerated cork stopper macerates. Moreover, the natural cork macerate with the highest content in polyphenol was perceived as being more bitter than that of microagglomerated cork stoppers.

Insights into the grape must composition effect on Hanseniaspora vineae performance and metabolic aroma compounds in Chardonnay base wine for sparkling wine production

This study compares the performance of Hanseniaspora vineae (Hv) under mixed culture fermentation with Saccharomyces cerevisiae, with a conventional control (Sc) for the production of base wine. Hv exhibited fermentation kinetics comparable to controls when its nutritional requirements were satisfied. Volatile acidity in Hv from one batch was significantly lower (–0.3 g/L) compared to the controls, while in the other two batches the levels were equal. Interestingly, Hv trials showed a significant degradation of malic acid (–0.9 g/L on average) without variations of pH. Even though the matrix influenced the volatile composition, the characteristic features of H. vineae remained intact, with 24-fold higher levels of 2-phenylethyl acetate. There was no higher production of 2-aminoacetophenone, albeit tryptophan (known as a 2-aminoacetophenone precursor) is a preferred amino acid for H. vineae. Results suggest the potential of H. vineae to produce base wine with a broad spectrum of aroma compounds that increase flavor complexity, if obtained from nutrient-balanced grape musts.

Effect of Protease Combined with Heat Treatment on the Volatile Composition and Aroma Quality in Liqueur Wine.

The aim of this paper was to compare the effects of two clarification methods, protease combined with heat treatment and bentonite, on the aroma quality of liqueur wines, and to identify and analyze the overall differences between the basic components and volatile aroma compounds of liqueur wines after the two treatments by chemical analysis, headspace-solid-phase microextraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS), and orthogonal partial least squares discriminant analysis (OPLS-DA). The results showed that total acidity, volatile acidity and pH in liqueur wines after protease combined with heat treatment were not significantly different from those of the blank control, and the ability to remove proteins was equal to that of the bentonite treatment. A total of 58 volatile aroma compounds were detected by HS-SPME-GC/MS. Compared with the blank control group (44 species, total 108.705 mg/L), 52 (83.233 mg/L) and 50 (120.655 mg/L) aroma compounds were detected in the bentonite and protease combined with heat treatments, respectively. Compared with the control and bentonite treatment, the protease combined with heat treatment significantly increased the total content of aromatic compounds in liqueur wines, and the types and contents of olefins, furans and phenols were higher. Among them, the compounds with major contributions in the protease combined with heat treatment were ionone, β-damascenone, 3-methyl-1-butanol, alpha-terpineol and limonene, which helped increase the content of terpenoids and enhance the floral and fruit aroma of the wine. Meanwhile, linalool, diethyl succinate, 2-methyl-3-heptanone, butanal diethyl acetal, hexanal and n-octanol were six compounds with high content of aromatic compounds unique to liqueur wines after protease combined with heat treatment. The sensory evaluation results were consistent with the results of aromatic compound detection, and the overall quality was better. The results may provide a reference for further exploration of protease-based clarifiers suitable for liqueur wines.