Estimation of Chemical Compounds in Selected Italian and French Wines Produced through Organic and Conventional Methods

Abstract

In this study, Italian and French wines produced through organic and conventional methods were analyzed. Three different varieties of wines were examined, including Cabernet Sauvignon, Merlot, and Syrah. Individual compounds were quantitatively and qualitatively analyzed to measure their levels of organic acids and polyphenols, such as phenolic acids, flavonoids, and anthocyanins, as well as their different chemical fractions. Among the French wines, organic varieties contained significantly higher levels of lactic and acetic acids, as well as catechins and rutin, compared to those of their conventional counterparts. Based on its chemical components, one of the best wines in this group was Syrah. In contrast, similar results were observed for the Italian wine produced by both systems. One type of Italian wine with superior results was Cabernet Sauvignon.

1. Introduction

Wine is among the oldest beverages produced by mankind and has been manufactured for centuries. However, the origins of wine production cannot be attributed to one culture. Much archaeological evidence and historical sources indicate that the production and consumption of wine appeared worldwide [1]. Historical references that describe wine production not only address medical or social issues but also describe the characteristics of different varieties of wine or grape cultivars. This finding demonstrates that knowledge on this drink was extensive in ancient times [2]. The foundation for wine production is grapes. Wine is produced by fermenting the sugars in grapes into alcohol [3]. The factors determining wine quality are known as the quality triad and include the grape cultivar, soil, and climate. Collectively, these triads are known as the terrior, which is a set of factors independent of humans; these factors are inextricably linked to a given area and have a decisive impact on the conditions for growing vines [4]. The climatic conditions during the year reflect the wine quality. As a result, no two vintages are identical. It is very difficult to predict the quality of grapes and wines from a given vintage [5]. The cultivation methods cover a large group of factors that determine the quality of wine. Organic farms system must follow restrictive rules regarding the use of fertilizers and plant protection products. Only natural fertilization methods are permitted, i.e., manure and compost, and the use of synthetic plant protection products and fertilizers is forbidden [6]. Some of the most popular grape cultivars used in viticulture are Cabernet Sauvignon, Syrah, or Merlot. Wines produced using those cultivars are characterized by a deep, ruby color, a good taste, and a characteristic odor [7,8,9]. The main healthy components obtained from wine consumption are polyphenols. These compounds are strong anticancer, ant-mutagenic, anti-inflammatory, and antioxidant agents. Many experiments have demonstrated the health-promoting effects of polyphenols on human health [10,11,12,13]. The main polyphenols identified in white wines are phenolic acids, including gallic, p-coumaric, sinapic, chlorogenic, and ferulic acids, while in red wines those identified are anthocyanin and resveratrol [11,12]. However, among flavonoids, the most common ones are catechin, epigallocatechin, quercetin, and kaempferol, as well as their chemical derivatives [14,15,16,17]. Compared to conventional foods, organic food and beverages are more valuable in terms of their nutritional value and bioactive compounds [18,19,20,21,22,23]. Many experiments on organic fruits and vegetables have confirmed that theory [24,25,26,27]. Based on the current literature, information on the chemical composition of wines produced using different grape cultivars under different growing and climate conditions is lacking. Therefore, the present research investigated how organic and conventional methods of wine production impact product quality.

2. Materials and Methods

2.1. Chemicals and Reagents

For analytical purposes, the following chemicals were used: acetonitrile (HPLC purity; aluminium chloride AlCl₃ (purity for analysis); deionized water; Folin–Ciocâlteu reagent (purity for analysis); methanol (purity for analysis); hydrochloric acid, HCl; phosphate-buffered saline (PBS); potassium persulfate, K₂S₂O₈ (purity for analysis); sodium hydroxide, NaOH (purity for analysis); the polyphenol standards of 3,4,5-trihydroxybenzoic acid, 1,4,5-trihydroxycyclohexanecarboxylic acid, p-coumaric acid, (+)-catechin, (−)-epigallocatechin, (−)-epigallocatechin gallate, 3,3′,4′,5,7-pentahydroxyflavone-3-rutinoside, kaempferol 3-β-D-glucopyranoside, quercetin, kaempferol, malvidin 3-β-D-glucopyranoside, kuromanin chloride, 3-(glucosyloxy)-4′,5,7-trihydroxy-3′-methoxyflavylium chloride, and organic acids; and the alcohol standards of ethanol, tartaric, succinic, lactic, and acetic acids. All chemicals and reagents were purchased from Sigma-Aldrich Company (Poznan, Poland) and Merck (Poznan, Poland). All the used standards were characterized by the HPLC purity.

2.2. Materials

The organic and conventional wine samples were purchased in shops with certified organic food and typical conventional food in Poland in 2022. Two bottles were obtained for each experimental kind of wine (per 0.75 L). One bottle was treated as an individual sample. The samples were subsequently transported to the laboratory where chemical analyses were performed. During analysis, wine bottles were kept in a refrigerator (5 °C and in a dark condition).

2.3. Wine Origin and Selection Criterias

2.3.1. Organic Wines

• Cabernet Sauvignon (France) comes from the large area of the Pays D’oc IGP appellation (IGP—Indication Géographique Protégée), which is located in the geographical region of Languedoc-Roussillon in Southern France. It is a harvest vintage from 2019.
• Cabernet Sauvignon (Italy) comes from the Italian appellation Venezia DOC (DOC—Denominazione di Origine Controllata), which is located in the geographical area of the province of Treviso (north-eastern part of Italy). It is a harvest vintage from 2016.
• Merlot (France) comes from a large area of the Pays D’oc IGP appellation (IGP—Indication Géographique Protégée), which is located in the geographical region of Languedoc-Roussillon in Southern France. It is a harvest vintage from 2017.
• Merlot (Italy) comes from the Italian appellation Trevenezie IGT (IGT—Indicazione Geografica Tipica), which is also present in the province of Treviso. It is a harvest vintage from 2020.
• Syrah (France) comes from a large area of the Pays D’oc IGP appellation (IGP—Indication Géographique Protégée), which is located in the geographical region of Languedoc-Roussillon in Southern France. It is a harvest vintage from 2017.
• Syrah (Italy) comes from the Sicilia DOC appellation (DOC—Denominazione di Origine Controllata) and guarantees that the grapes used to produce the wine come from the island of Sicily.

2.3.2. Conventional Wines

• Cabernet Sauvignon (France) comes from the large area of the Pays D’oc IGP appellation (IGP—Indication Géographique Protégée), which is located in the geographical region of Languedoc-Roussillon in Southern France. It is a harvest vintage from 2019.
• Cabernet Sauvignon (Italy) comes from the Italian appellation Trevenezie IGT (IGT—Indicazione Geografica Tipica), which is also present in the province of Treviso. It is a harvest vintage from 2020.
• Merlot (France) comes from a large area of the Pays D’oc IGP appellation (IGP—Indication Géographique Protégée), which is located in the geographical region of Languedoc-Roussillon in Southern France. It is a harvest vintage from 2019.
• Merlot (Italy) comes from the Italian appellation Trevenezie IGT (IGT—Indicazione Geografica Tipica), which is also present in the province of Treviso. It is a harvest vintage from 2019.
• Syrah (France) comes from the large area of the Pays D’oc IGP appellation (IGP—Indication Géographique Protégée), which is located in the geographical region of Languedoc-Roussillon in Southern France. It is a harvest vintage from 2020.
• Syrah (Italy) comes from the Terre Siciliane IGP appellation (Indicazione Geografica Protetta). It is a harvest vintage from 2021 (Figure S1).

The terroir and the climate of the Veneto (Trevenezie and Venezia appellations) include the area planted with vines, which is characterized by a small slope and low location relative to sea level. The quality of the wine is dictated by the location of the vines above sea level (the higher the better). The climate is characterized by mild winters and hot summers with regular rainfall.

The terroir and climate of Languedoc-Roussillon (Pays D’oc appellation) include diverse soils with admixtures of bedrock, shales, limestones, and sandstones. They are characterized by a Mediterranean climate with hot, dry summers and a gentle influence of the Atlantic in the western part of the region.

Wine selection involves the selection of wines from different geographical latitudes (Southern France for wines from the Languedoc-Roussillon region, Northern Italy for wines from the Veneto region, and Southern Italy for wines from Sicily). Different latitudes determine the number of sunny days per year, which directly affects the ripeness of the grapes and the sugar content that must be produced from these fruits. A higher sugar content in the case of complete fermentation means a higher alcohol concentration in the wine produced. Single-varietal wines were selected (Cabernet Sauvignon, Merlot, and Syrah), which came from organic and conventional farming. Each strain has its own characteristic quality features, including sensory ones.

2.4. Dry Matter Analysis

The dry matter of the examined wines was determined through the gravimetric method [28]. The glass beaker was weighed, and the next small portion (5 mL) of wine was poured inside. The beaker was weighed again and placed into the laboratory drier Farma Play FP-25 W (Bielsko-Biala, Poland). After 72 h at 105 °C, the samples were cooled in a desiccator to room temperature and weighed again. The dry matter content was calculated on the basis of fresh and dry mass differences before and after the drying process. The results are presented as the dry matter content per g/L of wine.

2.5. Total Polyphenol Analysis

The Folin–Ciocâlteu method was applied [29]. Briefly, 1 mL of the wine sample was placed into a 250 mL beaker, and 50 mL of 80% methanol was added. The samples were sonicated for 15 min at 6 kHz and 30 °C. Next, the samples were centrifuged at 6000 rpm and 0 °C for 10 min (Hermle Z 300 K, Wroclaw, Poland). The supernatant was used for the assays. Tested samples (1.0 mL) were poured into 50 mL volumetric flasks, with 2.5 mL of Folin–Ciocâlteu reagent (Chempur, Piekary Śląskie, Polska) and 5.0 mL of 20% sodium carbonate (Na₂CO₃, Chempur, Piekary Śląskie, Polska) being added. The samples were incubated for 45 min at ambient temperature without light access. Next, the absorbance was measured with a spectrophotometer (BioSENS UV-6000, Warsaw, Poland) at a wavelength of 750 nm. The total polyphenol content was calculated with an equation (R² = 0.998) with a dilution coefficient. The results are presented as gallic acid equivalents (GAE) per mg/L of wine.

y = (2.128 × (absorbance) + 0.1254) × 100

2.6. Total Flavonoid Analysis

The total flavonoid contents were determined by the colorimetric method [30]. One milliliter of the wine sample was mixed with methanol. The samples were sonicated (15 min, 6 kHz, 30 °C) and centrifuged at 6000 rpm and 0 °C for 10 min (Hermle Z 300 K, Wroclaw, Poland). The obtained extract (5 mL) was combined with sodium acetate C₂H₃NaO₂ (5.0 mL, 100 g L⁻¹) and aluminium chloride AlCl₃ (3.0 mL, 25 g L⁻¹). To replenish, 25 mL of the samples was added in a volumetric flask methanol. The two solutions were measured with the same mixture, but one of them was without the reagent (AlCl₃). Measurement of absorbance was at 425 nm. The total flavonoid content was determined by the calibration curve of rutin (quercetin-3-O-rutinoside, R² = 0.9999), and the results were presented as mg/L of wine.

y = (6.581 × (absorbance) + 0.364) × 30

2.7. Total Anthocyanin Analysis

The total anthocyanin contents were measured by the colorimetric method [31]. One milliliter of the examined wine sample was mixed with 50 mL of the extractant mixture (1.5 Mol HCl and methanol v:v 85:15). Next, the samples were mixed on a vortex (326 M; Marki, Poland) and centrifuged (Hermle Z 300 K; Wroclaw, Poland) for 10 min at 5500 rpm and 0 °C. After that, the samples were transferred into 100 mL volumetric flasks and filled with the extracted mixture. Ten milliliters of the sample was transported to the next (smaller) volumetric flask (25 mL), after which the mixture was filled again. After sample mixing (upward and downward), the sample was transferred to a glass cuvette. The absorbance was measured at 530 nm. The total anthocyanin content was calculated using the mathematical formula obtained from the calibration curve of delphinidin (delphinidin chloride), R² = 0.9987), and the results are presented as mg/L of wine.

y = (752.82 × (absorbance) + 0.7655) × 2.5

2.8. Total Organic Acid Analysis

The total organic acid content was measured by the titration method [32]. Five milliliters of the wine sample was mixed with 100 mL of distilled water and boiled. After that, the samples were cooled to room temperature in a cold-water bath (DanLab, 800 W, Kraków, Poland). The samples were transferred to a volumetric flask (250 mL), after which the water was added. The samples were filtered through paper filters and funneled into Erlenmeyer flasks (250 mL). A small amount of sample (25 mL) was mixed with distilled water and titrated with NaOH (0.1 mol) until a pH of 8.0 was obtained. The total organic acid content was calculated according to the following mathematical formula: V is the volume of NaOH used for titration in ml; N is the NaOH normality (0.1); V1 is the volume of the filtrate taken for titration; V₀ is the volume to which the material sample was added; mL is the sample volume in mL; and K is the coefficient for converting the result into the appropriate organic acid. In the case of wine, the dominant compound was tartaric acid, with a titer of K = 0.075.

y = (V × N × K × V₀ × 100)/(V1 × mL)

2.9. Identification of Polyphenols by HPLC

Individual flavonoids and phenolic acids were examined by HPLC [33]. Briefly, 1 mL of the samples was extracted with 5 mL of 80% methanol by sonication for 10 min at 6 kHz and 30 °C. After that, the samples were centrifuged (Hermle Z 300 K, Wroclaw, Poland; 10 min, 6000 rpm, temp. 0 °C). Fifty microliters of sample extract was analyzed by the HPLC system with a Fusion RP-80 A column (250 × 4.6 mm²; Phenomenex, Warsaw, Poland). The analysis was carried out with the use of Shimadzu equipment (USA Manufacturing Inc., New Providence, IA, USA; two pumps LC-20AD, controller CBM-20A, column oven SIL-20AC, spectrometer UV/Vis SPD-20 AV). The mobile phase was prepared from acetonitrile and water with phosphoric acid (pH 3.0). The gradient flow of 1 mL min⁻¹ was applied as follows: 1.00–22.99 min, 95% phase A and 5% phase B; 23.00–27.99 min, 50% phase A and 50% phase B; 28.00–28.99 min, 80% phase A and 20% phase B; and 29.00–38.00 min, 95% phase A and 5% phase B. The single run lasted 42 min. The detection wavelength for flavonoids was at 360 nm, and the detection of phenolic acids was at 250 nm. Polyphenols were identified based on the retention time of external standards (gallic, chlorogenic, caffeic, p-coumaric acid, catechin, epigallocatechin, epigallocatechin gallate, quercetin-3-O-rutinoside, kaempferol-3-O-glucoside, quercetin, and kaempferol) and were calculated using calibration curves (R² = 0.999). All standard curves are presented in Supplementary Materials as Figures S2 and S3.

2.10. Identification of Individual Anthocyanins by HPLC

Individual anthocyanins were extracted and measured via HPLC [34]. To extract the samples, polyphenols were added (see description above in Section 2.8). A total of 2.5 mL of supernatant was placed into a testing tube with 2.5 mL of 10 Mol HCl and 5 mL of pure methanol. The samples were mixed with a vortex (326 M; Marki, Poland) and left at low temperature (0 °C) for 10 min. Afterwards, 50 µL of extract was injected into a Fusion RP-80 A column (250 × 4.6 mm²; Phenomenex, Warsaw, Poland). An isocratic phase (5% acetic acid, acetonitrile, methanol (70:10:20)) was used with a flow rate of 0.5 mL min⁻¹. The pump pressure ranged from 10.00 to 12.00 mPa. The analysis time was 18 min, and the detection wavelength for flavonoids was 530 nm. Anthocyanins were identified based on retention time and external standards (malvidin-3-O-glicoside, petunin-3-O-glucoside, and peonidin-3-O-glucoside). All standard curves are presented in Supplementary Materials as Figure S4.

2.11. Identification of Individual Organic Acids and Alcohols by HPLC

Individual organic acids and alcohols were extracted and measured via HPLC [35]. One milliliter of the wine sample was diluted with distilled water (10 times). The next sample was centrifuged (Hermle Z 300 K, Wroclaw, Poland; 5000 rpm, 10 min, 2 °C). A total of 1.5 mL of the supernatant was filtered through a 0.22 µm PES syringe filter and put into an HPLC vial. A total of 25 µL of the sample was injected onto an Aminex HPX-87H column (BioRad, Warsaw, Poland; 300 × 7.8 mm², 9 µm, 8% cross linkage, pH 1–3). An isocratic phase (10 mMol sulfuric acid) was used with a flow rate of 0.5 mL min⁻¹. The analysis time was 75 min, and the detection wavelength was 210 nm. Organic acids were identified based on retention time and external standards (ethanol, tartaric, succinic, lactic, and acetic acids). All standard curves for organic acids and alcohols are presented in Supplementary Materials as Figure S5.

2.12. Statistical Analysis

Statgraphics Centurion 15.2.11.0 software (StatPoint Technologies, Inc., Warrenton, VA, USA) was used for analyses. Two-way ANOVA using Tukey’s test (α = 0.05) was applied. The factors of the experiment were the type of wine produced (ORG vs. CONV) and the kind of wine produced (Cabernet Sauvignon, Merlot, and Syrah). In the tables, standard errors nested to average values were applied. From each bottle, 3 laboratory repetitions were performed. The total number of repetitions for the organic (n = 12), conventional (n = 12), Cabernet Sauvignon (n = 12), Merlot (n = 12), and Syrah (n = 12) systems for Italian and French wines were recorded. Different letters indicate statistically significant differences between sample groups. Principal component analysis was performed based on the correlation matrix. The PCA figures were made using XLStat (Microsoft Excel version 16.18).

3. Results

The dry matter of the French wine samples is presented in

Table 1. The content of dry matter (g/100 mL), total organic acids (g/L), and polyphenols (mg/L) in different kinds of French wines from organic and conventional production.

Experimental Combination/Groups of Compounds	Organic Wines			Conventional Wines			p-Value
	Cabernet	Merlot	Syrah	Cabernet	Merlot	Syrah
total organic acids	665.1 ± 13.9 a	630.3 ± 2.7 a	577.9 ± 5.1 b	558.0 ± 5.2 b	412.8 ± 1.8 c	247.9 ± 5.1 d	0.0001
total polyphenols	383.1 ± 2.4 c	460.3 ± 6.6 b	559.6 ± 7.0 a	430.3 ± 4.7 b	459.9 ± 0.8 b	590.2 ± 2.5 a	0.0280
total flavonoids	251.1 ± 2.2 c	327.3 ± 1.5 b	432.5 ± 4.1 a	252.8 ± 2.9 c	254.4 ± 3.3 c	352.9 ± 3.0 b	0.0001
total anthocyanins	154.5 ± 1.7 c	250.5 ± 2.5 a	298.3 ± 1.3 a	189.3 ± 1.7 b	189.2 ± 1.8 b	259.8 ± 2.6 a	<0.0001
dry matter	2.30 ± 0.01 a	2.31 ± 0.09 a	2.14 ± 0.06 b	2.22 ± 0.02 ab	1.91 ± 0.05 b	2.35 ± 0.03 a	0.017
Experimental Combination/Groups of Compounds	Organic wines	Conventional wines	Cabernet	Merlot	Syrah	p-value (organic and conventional)	p-value (kind of wine)
total organic acids	624.4 ± 15.5 a	406.2 ± 51.8 b	611.5 ± 26.0 a	521.5 ± 54.4 b	412.9 ± 82.6 c	<0.0001	<0.0001
total polyphenols	467.7 ± 29.7 b	493.5 ± 28.4 a	406.7 ± 11.5 b	460.1 ± 3.3 b	574.9 ± 8.5 a	0.0029	<0.0001
total flavonoids	337.1 ± 30.3 a	286.7 ± 19.2 b	252.2 ± 1.9 b	290.9 ± 18.3 b	392.7 ± 20.1 a	<0.0001	<0.0001
total anthocyanins	234.4 ± 24.4 a	212.8 ± 13.6 b	171.9 ± 8.3 b	219.9 ± 15.4 a	279.1 ± 9.7 a	0.0001	<0.0001
dry matter	2.25 ± 0.05 a	2.16 ± 0.08 a	2.26 ± 0.02 a	2.11 ± 0.11 a	2.25 ± 0.06 a	N.S.	N.S.

Data are presented as the mean ± SE with ANOVA p-value; means in rows followed by the different letters are significantly different at the 5% level of probability (p < 0.05). N.S.—not statistically significant.

. We did not observe significant differences for the organic and conventional samples. The grape cultivars did not impact the content of the dry matter in the French wine samples. Only interactions between experimental factors play an important role. The organic Merlot and conventional Syrah wines were characterized by a significant (p-value = 0.017) increase in dry matter content (Table 1). For the Italian wines, organic samples contained significantly (p-value = 0.043) higher levels of dry matter compared to those of the conventional samples. The grape cultivar significantly (p-value = 0.0008) affected the content of dry matter in the Italian wines. Compared to the other examined wine samples, the Syrah wine exhibited the highest level of dry matter (

Table 2. The content of dry matter (g/100 mL), total organic acids (g/L), and polyphenols (mg/L) in different kinds of Italian wines from organic and conventional production.

Experimental Combination/Groups of Compounds	Organic Wines			Conventional Wines
	Cabernet	Merlot	Syrah	Cabernet	Merlot	Syrach	p-Value
total organic acids	516.6 ± 3.0 a	147.9 ± 1.6 c	395.9 ± 3.7 b	182.0 ± 2.4 c	186.2 ± 3.7 c	585.4 ± 3.5 a	<0.0001
total polyphenols	490.1 ± 0.3 a	391.1 ± 2.5 b	403.8 ± 1.5 a	436.7 ± 2.1 a	385.8 ± 7.9 c	389.1 ± 1.8 c	0.0075
total flavonoids	358.4 ± 0.9 a	334.5 ± 5.0 a	298.4 ± 1.3 ab	256.7 ± 0.3 b	251.0 ± 4.2 b	243.4 ± 2.6 b	0.004
total anthocyanins	249.8 ± 0.8 a	260.3 ± 2.5 a	254.0 ± 3.8 a	180.6 ± 1.5 a	177.4 ± 1.8 a	188.5 ± 2.2 a	N.S.
dry matter	2.14 ± 0.03 a	2.44 ± 0.03 a	2.98 ± 0.01 a	2.66 ± 0.01 a	2.62 ± 0.03 a	2.45 ± 0.05 a	N.S.
Experimental Combination/Groups of Compounds	Organic wines	Conventional wines	Cabernet	Merlot	Syrah	p-value (organic and conventional)	p-value (cultivar)
total organic acids	353.5 ± 62.7 a	317.8 ± 77.3 b	349.3 ± 78.9 b	167.0 ± 9.8 c	490.6 ± 47.4 a	0.0001	<0.0001
total polyphenols	428.3 ± 18.0 a	403.8 ± 9.9 b	463.4 ± 12.7 a	388.4 ± 4.4 b	396.4 ± 3.9 b	0.0011	<0.0001
total flavonoids	330.5 ± 10.2 a	250.4 ± 2.8 b	307.6 ± 24.0 a	292.8 ± 21.1 b	270.9 ± 13.8 b	<0.0001	0.0003
total anthocyanins	254.7 ± 2.3 a	182.2 ± 2.2 b	215.2 ± 16.3 a	218.9 ± 20.8 a	221.3 ± 16.5 a	<0.0001	N.S.
dry matter	2.52 ± 0.14 a	2.58 ± 0.04 a	2.40 ± 0.13 b	2.53 ± 0.05 b	2.71 ± 0.14 a	0.043	0.0008

Data are presented as the mean ± SE with ANOVA p-value; means in rows followed by the different letters are significantly different at the 5% level of probability (p < 0.05). N.S.—not statistically significant.

).

Compared with the conventional wines, the French organic wines contained significantly more organic acids (p-value < 0.0001), total flavonoids (p-value < 0.0001), and total anthocyanins (p-value = 0.0001) (Table 1). Only the total polyphenols were present at the highest concentrations in the conventional samples (p = 0.0029). The level of total polyphenols (p-value < 0.0001), including that of total flavonoids (p < 0.0001) and anthocyanins (p-value < 0.0001), was significantly higher in the Syrah wine than in the other examined kinds of wine (Table 1). In the case of interactions, we observed that Cabernet Sauvignon grapes contained significant amounts of (p-value = 0.0001) total organic acids in both systems. Similarly, compared to the other French wines, Syrah was much richer in total polyphenols (p-value = 0.02800), total flavonoids (p-value = 0.0001), and total anthocyanins (p-value < 0.0001) (Table 1). The chemicals identified in French wines are shown in

Table 3. The mean values for ethanol (%), individual organic acids (g/L), and individual identified polyphenols (mg/L) in different kind of French wines from organic and conventional production.

Experimental Combination/Compounds	Organic Wines	Conventional Wines	Cabernet	Merlot	Syrah	p-Value (Production)	p-Value (Kind of Wine)
ethanol	11.9 ± 0.9 b	12.9 ± 0.5 a	12.9 ± 0.8 a	11.5 ± 1.3 b	12.9 ± 0.3 a	0.0025	0.002
tartaric	196.2 ± 4.5 a	193.4 ± 14.9 a	205.6 ± 6.2 a	211.9 ± 10.1 a	166.9 ± 10.5 b	N.S.	0.017
succinic	148.9 ± 3.7 a	117.5 ± 24.4 a	158.2 ± 7.1 a	147.1 ± 15.6 a	94.3 ± 26.1 b	N.S.	0.035
lactic	160.7 ± 16.7 a	85.0 ± 25.0 b	168.6 ± 24.2 a	114.2 ± 23.6 a	85.8 ± 33.0 a	0.031	N.S.
acetic	48.9 ± 5.8 a	27.5 ± 11.3 a	46.3 ± 7.8 a	47.6 ± 12.7 a	20.7 ± 10.4 a	N.S.	N.S.
gallic	23.1 ± 3.6 a	25.6 ± 3.4 a	24.6 ± 5.5 a	23.2 ± 3.0 a	25.2 ± 4.2 a	N.S.	N.S.
chlorogenic	72.5 ± 4.1 b	115.5 ± 7.9 a	80.7 ± 8.0 b	97.7 ± 5.5 a	103.7 ± 19.0 a	<0.0001	0.0001
caffeic	14.4 ± 0.8 b	27.4 ± 4.0 a	22.2 ± 4.7 a	13.7 ± 0.3 b	26.8 ± 5.0 b	<0.0001	0.0001
p-coumaric	9.3 ± 1.3 a	8.3 ± 0.7 b	5.6 ± 0.3 c	11.2 ± 0.5 a	9.5 ± 0.7 b	0.027	<0.0001
catechin	1.6 ± 0.02 a	1.5 ± 0.01 b	1.6 ± 0.05 a	1.6 ± 0.05 a	1.5 ± 0.02 b	<0.0001	0.0001
epigallocatechin	1.6 ± 0.1 b	2.0 ± 0.6 a	2.9 ± 0.5 a	1.7 ± 0.1 b	0.8 ± 0.2 c	0.0015	<0.0001
epigallocatechin gallate	2.6 ± 0.5 a	2.1 ± 0.5 b	3.9 ± 0.1 a	2.2 ± 0.4 b	0.9 ± 0.1 c	0.0013	<0.0001
quercetin-3-O-rutinoside	0.2 ± 0.03 a	0.1 ± 0.04 b	0.2 ± 0.03 a	0.2 ± 0.06 a	0.1 ± 0.03 b	<0.0001	0.0017
kaempferol-3-O-glucoside	0.7 ± 0.10 a	0.7 ± 0.10 a	0.8 ± 0.14 a	0.8 ± 0.11 a	0.5 ± 0.02 b	N.S.	<0.0001
quercetin	0.9 ± 0.06 a	1.0 ± 0.05 b	0.9 ± 0.01 b	1.0 ± 0.08 a	1.1 ± 0.01 a	0.0001	<0.0001
kaempferol	1.0 ± 0.01 b	1.1 ± 0.04 a	1.1 ± 0.01 a	1.1 ± 0.06 a	1.0 ± 0.01 b	<0.0001	<0.0001
malvidin-3-O-glucoside	89.3 ± 9.8 a	68.9 ± 3.6 b	66.2 ± 1.9 b	68.9 ± 3.3 b	102.1 ± 10.4 a	<0.0001	<0.0001
petunin-3-O-glucoside	15.8 ± 0.7 b	21.6 ± 4.5 a	15.7 ± 0.9 b	15.2 ± 0.7 b	25.3 ± 5.9 a	<0.0001	<0.0001
peonidin-3-O-glucoside	5.7 ± 1.7 a	4.8 ± 1.4 b	2.8 ± 0.1 b	2.4 ± 0.1 b	10.6 ± 0.5 a	<0.0001	<0.0001

Data are presented as the mean ± SE with ANOVA p-value; means in rows followed by the different letters are significantly different at the 5% level of probability (p < 0.05). N.S.—not statistically significant.

. Compared to the organic samples, the conventional samples were characterized by a significantly higher concentration of ethanol (p-value = 0.0025). Four individual organic acids were identified in French wines, but only the lactic acid concentration was significantly higher in organic wines (p-value = 0.031). Compared to the conventional samples, the Italian organic wines were characterized by a significantly higher concentration of all the examined total parameters (

Table 4. The content of ethanol (%), individual organic acids (g/L), and individual identified polyphenols (mg/L) as an effect of the interaction kind of production and grape variety in Franch wines.

Experimental Combination/Compounds	Organic Wines			Conventional Wines			p-Value
	Cabernet	Merlot	Syrah	Cabernet	Merlot	Syrah
ethanol	14.4 ± 0.1 a	8.91 ± 0.1 c	12.5 ± 0.1 b	11.4 ± 0.1 bc	14.1 ± 0.1 a	13.4 ± 0.1 ab	<0.0001
tartaric acid	195.3 ± 0.3 a	205.5 ± 0.1 a	187.7 ± 0.2 a	215.9 ± 0.1 a	218.3 ± 0.1 a	146.1 ± 0.1 a	N.S.
succinic acid	150.3 ± 3.9 a	150.2 ± 8.8 a	146.1 ± 3.2 ab	166.1 ± 5.8 a	144.1 ± 17.1 b	42.4 ± 1.2 c	0.047
lactic acid	202.9 ± 6.0 a	128.2 ± 5.9 a	151.1 ± 6.9 a	134.3 ± 10.1 a	100.3 ± 30.4 a	20.5 ± 0.1 a	N.S.
acetic acid	47.2 ± 30.3 a	61.4 ± 6.0 a	38.3 ± 9.0 a	45.5 ± 15.6 a	33.9 ± 44.6 a	3.1 ± 0.1 a	N.S.
gallic acid	35.0 ± 6.1 a	17.3 ± 2.2 b	17.0 ± 9.0 b	14.3 ± 14.4 c	29.1 ± 21.3 a	33.5 ± 0.1 a	0.0002
chlorogenic acid	65.2 ± 3.4 c	86.7 ± 0.4 bc	65.7 ± 11.1 c	96.1 ± 0.1 b	108.7 ± 0.2 a	141.7 ± 1.1 a	<0.0001
caffeic acid	12.9 ± 1.7 c	13.3 ± 0.1 c	16.9 ± 1.0 b	31.5 ± 3.5 a	14.1 ± 0.8 bc	36.6 ± 0.2 a	0.0004
p-coumaric acid	5.0 ± 0.3 c	12.1 ± 0.2 a	10.7 ± 0.4 a	6.3 ± 1.5 b	10.4 ± 0.4 a	8.3 ± 1.1 b	0.0071
catechin	1.7 ± 0.1 a	1.7 ± 0.3 a	1.6 ± 0.8 b	1.5 ± 0.1 b	1.5 ± 0.3 b	1.5 ± 0.1 b	<0.0001
epigallocatechin	2.0 ± 0.1 b	1.5 ± 0.1 c	1.3 ± 0.6 c	3.8 ± 0.1 a	1.9 ± 0.1 b	0.3 ± 0.1 d	<0.0001
epigallocatechin gallate	3.8 ± 0.1 a	3.1 ± 0.1 a	0.8 ± 0.1 d	3.9 ± 0.1 a	1.4 ± 0.2 b	1.0 ± 0.1 c	0.0001
quercetin-3-O-rutinoside	0.1 ± 0.01 b	0.3 ± 0.01 a	0.2 ± 0.01 b	0.3 ± 0.01 a	0.1 ± 0.01 b	0.1 ± 0.01 b	<0.0001
kaempferol-3-O-glucoside	0.5 ± 0.01 b	1.0 ± 0.02 a	0.6 ± 0.02 b	1.1 ± 0.01 a	0.6 ± 0.01 b	0.5 ± 0.01 b	<0.0001
quercetin	0.9 ± 0.02 b	0.7 ± 0.01 b	1.2 ± 0.01 a	0.8 ± 0.02 b	1.1 ± 0.02 a	1.1 ± 0.02 a	<0.0001
kaempferol	1.1 ± 0.01 a	1.0 ± 0.01 b	1.0 ± 0.01 b	1.1 ± 0.01 b	1.2 ± 0.02 a	0.1 ± 0.01 c	<0.0001
malvidin-3-O-glucoside	69.7 ± 1.6 b	75.2 ± 1.9 b	122.9 ± 0.4 a	62.8 ± 0.4 b	62.6 ± 0.2 b	81.3 ± 0.3 a	0.0001
petunin-3-O-glucoside	17.5 ± 0.1 b	16.6 ± 0.1 b	13.5 ± 0.1 c	14.0 ± 0.1 c	13.8 ± 0.1 c	37.1 ± 0.1 a	<0.0001
peonidin-3-O-glucoside	2.9 ± 0.1 c	2.7 ± 0.1 c	11.6 ± 0.1 a	2.6 ± 0.1 c	2.2 ± 0.1 c	9.5 ± 0.1 b	<0.0001

Data are presented as the mean ± SE with ANOVA p-value; means in rows followed by the different letters are significantly different at the 5% level of probability (p < 0.05). N.S.—not statistically significant.

). For the cultivars we observed, the Syrah wine was characterized by a significant increase in total organic acids (p-value < 0.0001), but the total polyphenols (p-value < 0.0001) in Cabernet Sauvignon included total flavonoids (p-value = 0.0003). The total anthocyanin content was not different for the different kinds of wine. One of the most interesting interactions was observed between the experimental factors and Cabernet Sauvignon wine. In both systems, the highest concentrations of total polyphenols (p-value = 0.0075) and total flavonoids (p-value = 0.004) were observed in these wines (Table 2).

A similar trend was observed for phenolic acids. The following individual compounds were identified in the examined samples: gallic, chlorogenic, p-coumaric, and caffeic acids (Table 2). The conventional French wines contained significantly more chlorogenic (p-value < 0.0001) and caffeic (p < 0.0001) acids. However, compared to the conventional samples, the organic samples contained significantly more p-coumaric acid (p-value = 0.027). Among the flavonoids, seven individual compounds were identified in French wines. The organic samples were characterized by a statistically significant content of catechin (p-value < 0.0001), epigallocatechin gallate (p = 0.0013), quercetin-3-O-rutinoside (p-value < 0.0001), and quercetin (p-value = 0.0001). However, the conventional French wines contained more epigallocatechin (p-value = 0.0015) and kaempferol (p-value < 0.0001). Among the anthocyanins, the presence of three pigments was confirmed, including malvidin-3-O-glucoside, petunin-3-O-glucoside, and peonidin-3-O-glucoside (Table 3). The organic French wine samples were characterized by significantly higher contents of malvidin-3-O-glucoside (p-value < 0.0001) and peonidin-3-O-glucodside (p-value < 0.0001) than those of the conventional wines, which contained higher amounts of petunin-3-O-glucoside (p-value < 0.0001). French Cabernet Sauvignon grapes contained significantly more tartaric acid (p-value = 0.035) and caffeic acid (p-value = 0.0001). Moreover, this kind of wine was characterized by a significantly higher concentration of epigallocatechin (p-value = 0.0015), epigallocatechin gallate (p-value = 0.0013), and kaempferol (p-value < 0.0001). The wine with the highest concentration of anthocyanins was Syrah. Compared to the other wine samples, the French wine samples contained significant higher concentrations of the identified anthocyanins (Table 3). Regarding the interactions, we observed a strong interaction for the French wine Cabernet Sauvignon. In both systems, these wines contained more succinic acid, catechin, epigallocatechin, and epigallocatechin gallate (Table 4). A similar trend was observed for the p-coumaric acid and catechin concentrations in Merlot wine. The French Syrah wine strongly interacted with the anthocyanins malvidin-3-O-glucoside and peonidin-3-O-glucoside in both production systems (Table 4).

The Italian organic wines were characterized by significantly higher concentrations of epigallocatechin gallate (p-value < 0.0001) and quercetin-3-O-rutinoside (p-value = 0.0515), as well as all the identified anthocyanins, including malvidin-3-O-glucoside (p-value < 0.0001), petunin-3-O-glucoside (p-value < 0.0001), and peonidin-3-O-glucodside (p-value = 0.0008) (

Table 5. The mean values for ethanol (%), individual organic acids (g/L), and individual identified polyphenols (mg/L) in different kinds of Italian wines from organic and conventional production.

Experimental Combination/Compounds	Organic Wines	Conventional Wines	Cabernet	Merlot	Syrah	p-Value (Production)	p-Value (Kind of Wine)
ethanol	12.6 ± 1.2 a	12.6 ± 0.6 a	11.8 ± 1.2 b	11.2 ± 0.4 b	14.8 ± 0.9 a	N.S.	0.0002
tartaric acid	146.5 ± 27.8 a	141.7 ± 25.9 a	130.8 ± 17.2 b	82.4 ± 7.3 c	219.2 ± 22.3 a	N.S.	0.0043
succinic acid	87.3 ± 26.1 a	79.3 ± 23.1 a	87.5 ± 20.2 a	29.7 ± 0.8 a	132.7 ± 31.8 a	N.S.	N.S.
lactic acid	76.5 ± 23.6 a	53.9 ± 24.8 a	65.0 ± 27.2 a	18.5 ± 4.1 a	112.0 ± 29.4 a	N.S.	N.S.
acetic acid	21.5 ± 5.9 a	18.7 ± 4.3 a	16.8 ± 5.8 a	3.0 ± 0.1 a	40.5 ± 11.7 a	N.S.	N.S.
gallic acid	24.8 ± 4.2 b	37.3 ± 5.3 a	36.6 ± 2.3 a	21.8 ± 1.0 b	34.7 ± 5.7 a	0.002	0.0047
chlorogenic acid	56.6 ± 2.5 b	76.6 ± 1.9 a	69.2 ± 5.7 a	63.3 ± 7.3 a	67.3 ± 2.6 a	0.0001	N.S.
caffeic acid	14.5 ± 0.8 b	26.0 ± 2.2 a	22.9 ± 4.3 a	22.3 ± 2.8 a	15.6 ± 1.6 b	<0.0001	0.0009
p-coumaric acid	8.9 ± 1.7 b	11.0 ± 1.4 a	12.9 ± 0.5 a	9.2 ± 2.7 b	7.7 ± 0.7 c	<0.0001	<0.0001
catechin	1.6 ± 0.01 a	1.6 ± 0.02 a	1.6 ± 0.03 a	1.6 ± 0.01 a	1.6 ± 0.01 a	N.S.	N.S.
epigallocatechin	1.0 ± 0.2 a	0.9 ± 0.1 a	1.3 ± 0.1 a	0.7 ± 0.2 b	0.8 ± 0.1 b	N.S.	0.0005
epigallocatechin gallate	3.2 ± 0.7 a	2.4 ± 0.7 b	4.2 ± 0.3 a	1.0 ± 0.1 c	3.1 ± 1.0 b	<0.0001	<0.0001
quercetin-3-O-rutinoside	0.3 ± 0.03 a	0.3 ± 0.09 b	0.4 ± 0.10 a	0.3 ± 0.2 a	0.2 ± 0.07 b	0.0515	0.0001
kaempferol-3-O-glucoside	0.5 ± 0.03 a	0.5 ± 0.03 a	0.4 ± 0.01 c	0.6 ± 0.02 a	0.5 ± 0.02 b	N.S.	0.0013
quercetin	0.8 ± 0.01 b	0.9 ± 0.03 a	0.9 ± 0.01 a	0.9 ± 0.05 a	0.8 ± 0.01 b	<0.0001	<0.0001
kaempferol	1.0 ± 0.02 a	1.0 ± 0.01 a	1.1 ± 0.02 a	1.0 ± 0.01 a	1.0 ± 0.01 a	N.S.	N.S.
malvidin-3-O-glucoside	76.3 ± 5.9 a	56.5 ± 2.0 b	79.4 ± 8.5 a	62.9 ± 3.3 b	56.9 ± 3.2 c	<0.0001	<0.0001
petunin-3-O-glucoside	23.1 ± 2.1 a	12.6 ± 0.2 b	16.4 ± 1.6 b	21.1 ± 4.6 a	16.1 ± 1.7 b	<0.0001	<0.0001
peonidin-3-O-glucoside	4.3 ± 0.4 a	3.3 ± 0.4 b	2.7 ± 0.1 c	4.9 ± 0.2 a	3.7 ± 0.6 b	0.0008	0.0001

Data are presented as the mean ± SE with ANOVA p-value; means in rows followed by the different letters are significantly different at the 5% level of probability (p < 0.05). N.S.—not statistically significant.

). However, gallic acid (p-value = 0.002), chlorogenic acid (p-value = 0.0001), caffeic acid (p-value < 0.0001), and p-coumaric acid (p-value < 0.0001) were significantly more abundant in the conventional wine samples. In regard to the compounds present, one of the best wines was Cabernet Sauvignon. In this sample, we found significantly more gallic, caffeic, and p-coumaric acids, as well as catechin, rutin, and malvidin-3-O-glucoside, than in the other Italian wines (Table 5). Italian Merlot wine contained two significantly more anthocyanin colorants as follows: petunin-3-O-glucoside (p-value < 0.0001) and peonidin-3-O-glucoside (p-value = 0.0008). The Italian Syrah wine was characterized by significant ethanol (p-value = 0.0002) and tartaric acid (p-value = 0.0043) contents (Table 5). In the case of interactions, both factors (production and kind of wine) affected the anthocyanin content in an interesting manner. Using the Italian Cabernet Sauvignon culture, we found the highest concentration of malvidin-3-O-glucoside in both production systems. However, for the Italian Merlot plants, the peonidin-3-O-glucoside concentration was low (

Table 6. The content of ethanol (%), individual organic acids (g/L), and individual identified polyphenols (mg/L) as an effect of the interaction kind of production and grape variety in Italian wines.

Experimental Combination/Compounds	Organic Wines			Conventional Wines			p-Value
	Cabernet	Merlot	Syrach	Cabernet	Merlot	Syrach
ethanol	9.3 ± 0.3 c	11.9 ± 0.1 bc	16.5 ± 0.5 a	14.2 ± 0.2 a	10.5 ± 0.3 c	13.2 ± 0.1 b	0.0001
tartaric acid	164.8 ± 5.4 a	67.8 ± 0.2 a	206.9 ± 42.8 a	96.8 ± 0.4 a	96.9 ± 0.5 a	231.4 ± 3.6 a	N.S.
succinic acid	126.9 ± 5.4 a	28.2 ± 0.5 a	106.8 ± 27.8 a	48.2 ± 0.1 a	31.1 ± 0.1 a	158.5 ± 5.8 a	N.S.
lactic acid	118.0 ± 14.9 a	26.6 ± 0.3 a	84.8 ± 21.6 a	12.0 ± 0.1 a	10.3 ± 0.1 a	139.3 ± 7.9 a	N.S.
acetic acid	30.0 ± 14.4 a	3.1 ± 0.1 a	31.3 ± 9.4 a	3.6 ± 0.1 a	2.8 ± 0.01 a	49.7 ± 7.1 a	N.S.
gallic acid	37.8 ± 4.3 b	21.0 ± 1.9 c	15.5 ± 0.3 d	35.4 ± 0.1 b	22.6 ± 0.1 c	54.0 ± 1.6 a	0.0008
chlorogenic acid	58.4 ± 2.1 c	48.8 ± 1.5 c	62.5 ± 0.1 b	79.9 ± 3.4 a	77.7 ± 1.3 a	72.0 ± 1.8 a	0.036
caffeic acid	14.4 ± 1.1 b	16.7 ± 0.1 b	12.4 ± 0.1 b	31.4 ± 1.3 a	27.9 ± 0.6 a	18.7 ± 0.4 b	0.0077
p-coumaric acid	13.8 ± 0.1 a	3.8 ± 0.2 e	9.1 ± 0.1 c	12.0 ± 0.1 b	14.7 ± 0.2 a	6.4 ± 0.1 d	<0.0001
catechin	1.6 ± 0.01 a	1.6 ± 0.01 a	1.6 ± 0.01 a	1.5 ± 0.01 a	1.6 ± 0.01 a	1.6 ± 0.01 a	N.S.
epigallocatechin	1.5 ± 0.03 a	0.4 ± 0.03 c	1.0 ± 0.02 b	1.1 ± 0.09 b	1.1 ± 0.05 b	0.5 ± 0.07 c	0.0006
epigallocatechin gallate	3.6 ± 0.01 b	0.8 ± 002 d	5.2 ± 0.07 a	4.9 ± 0.01 a	1.2 ± 0.06 c	1.0 ± 0.14 c	<0.0001
quercetin-3-O-rutinoside	0.2 ± 0.01 b	0.3 ± 0.02 b	0.3 ± 0.01 b	0.6 ± 0.02 a	0.3 ± 0.01 b	0.1 ± 0.01 b	<0.0001
kaempferol-3-O-glucoside	0.5 ± 0.01 a	0.6 ± 0.02 a	0.5 ± 0.01 a	0.4 ± 0.01 a	0.6 ± 0.02 a	0.6 ± 0.02 a	N.S.
quercetin	0.8 ± 0.01 a	0.8 ± 0.01 a	0.9 ± 0.01 a	0.9 ± 0.01 a	1.0 ± 0.01 a	0.8 ± 0.01 a	N.S.
kaempferol	1.1 ± 0.01 a	1.0 ± 0.01 a	1.0 ± 0.01 a	1.0 ± 0.01 a	1.0 ± 0.01 a	1.1 ± 0.01 a	N.S.
malvidin-3-O-glicoside	96.3 ± 0.4 a	69.4 ± 0.5 b	63.3 ± 0.1 b	62.4 ± 0.1 b	56.4 ± 0.1 c	50.6 ± 0.1 c	<0.0001
petunin-3-O-glucoside	19.6 ± 0.1 b	30.2 ± 0.2 a	19.6 ± 0.1 b	13.3 ± 0.1 c	12.0 ± 0.1 c	12.7 ± 0.1 c	<0.0001
peonidin-3-O-glucoside	2.8 ± 0.1 b	5.1 ± 0.1 a	4.9 ± 0.2 a	2.6 ± 0.1 b	4.6 ± 0.1 a	2.6 ± 0.1 b	0.0034

Data are presented as the mean ± SE with ANOVA p-value; means in rows followed by the different letters are significantly different at the 5% level of probability (p < 0.05). N.S.—not statistically significant.

).

Based on the PCA results, the overall degree of variability explained by F1 and F2 was 78.52% for Italian wines (Figure 1). This result was confirmed by a strong link between the chemical composition of organic and conventional wine samples and the kind of wines (Cabernet, Syrah, and Merlot). In the case of the Italian samples, all experiment objects (wines) were located in separate areas and were not very close. The observations indicate that the quality of organic wines significantly depended on the content of acetic, tartaric acids, ethanol content, as well as the catechin and dry matter concentration in the examined samples (Figure 1). The quality of the conventional samples was significantly influenced by caffeic and p-coumaric acids, malvidin-3-O-gluucoside, and quercetin-3-O-glucoside. In the case of French wines, we observed other relationships. Merlot and Cabernet were very close to each other in the plot, but the location of Syrah was completely different. The quality of conventional wines was significantly influenced by chlorogenic, gallic, caffeic acids, ethanol content, and petunidin-3-O-glucoside (Figure 2). The organic wines were closely related to a high concentration of acetic, lactic acids, quercetin-3-O-glucoside, and catechin content (Figure 2).

4. Discussion

Polyphenolic compounds are produced by plants for defensive purposes under states of increased biotic or abiotic stress. These compounds can also be called “natural pesticides”. The content of biologically active compounds in fruit depends mainly on the cultivation method and cultivar. In this study, the content of polyphenolic compounds significantly differed between wines of organic and conventional origin. By comparing our data with data from the literature and comparing organically and conventionally produced wines, it was determined that the results presented in the different studies did not correspond.

For comparison, in a study conducted by Bunea et al. [36], the total polyphenol content of several table grapes cultivated in organic and conventional agriculture were analyzed. For organic farming, the total polyphenol content ranged from 16.3 to 134.1 mg GAE/100 g FW, and the total polyphenol content ranged from 14.8 to 123.1 mg GAE/100 g FW for the conventional grapes. Mostly, when raw materials as grapes contain a higher concentration of polyphenols, the final products of wines contain a higher level as well. On the other hand, the technique of wine production can change this balance. After processing, the organic product can be characterized by a lower level of the total polyphenols compared to that of the conventional one. A similarity was noticed for raw red beetroots and press beetroot juices. Organic beetroots contained significantly more total polyphenols, while for press juices, conventional samples were characterized by a higher total polyphenols concentration [19,37]. Another study [38] compared the chemical profile of organic wines and wines created from non-organic grapes, which were grown in a selected region—Kutná Hora (Czech Republic). The analyzed wines were produced using the same grape wine cultivar in the Kutná Hora area, and several analyses were performed on the wine samples. The phenolic profiles and the present study revealed the precise differences between the organic and conventional wines produced using the same cultivar and the same region. Although a higher number of bioactive substances is expected for organically produced wines, in most cases, no statistically significant difference was observed for the amount of these substances in organic wines; in contrast, these substances were often more abundant in wines from integrated production. In the next study [39], using Brazilian organic and conventional wines, three commercial wines were produced using the varieties (Vitis vinifera) organic Tempranillo, conventional Tempranillo, and Barbera organic. Similar results were obtained for all the samples from the same cultivars and for the grapes of the two cultivation systems. Conventional products presented higher anthocyanin contents, but no significant differences were observed in the contents of other phenolic compounds. Gallic acid is responsible for the creation of the characteristic astringent taste of wine. In the presented results, both French and Italian Syrah wines were characterized by the highest content of gallic acid (Table 3 and Table 5). A similar observation was made in a study with French Syrah wines. In three different varieties of wine (Cabernet Sauvignon, Merlot, and Syrah) only Syrah was characterized by the highest level of gallic acid [8,40]. The concentration of gallic acid in Syrah wine may affect the taste of the final product. In a sensory experiment carried out with two Cabernet Sauvignon and Syrah samples, only Syrah obtained a higher note for astringent taste before Cabernet Sauvignon, which was evaluated as being sweeter than Syrah [7]. Hasanaliyeva et al. [41] conducted an experiment with red wines created from Kotsifali and white wines created from Vidiano grapes, which were collected from 13 organic and 13 conventional grape orchards. The production system did not significantly affect the total phenolic content. The anthocyanin profiles were only analyzed in the wine from red grapes (Kotsifali), and the production system did not cause significant effects. However, another study [20] showed the advantages of organic grapes and wines. The researchers studied the phenolic compounds from Monastrell variety grapes obtained through organic and conventional agriculture during the last month of ripening and the wines obtained from those plants. The total amount of phenolic compounds one month before harvesting was higher for the organic grapes (97.42 mg/100 g) than the conventional grapes (44.77 mg/100 g), although these differences were not observed at the time of harvest. The content of phenolic compounds was slightly higher in organic wine than in conventional wine, although the differences were not significant. This was confirmed by Parpinello et al. [42], who investigated the effect of two sustainable management practices (biodynamic and organic) on the chemical composition characteristics of Sangiovese red wines. The results confirmed the trend observed by other researchers. The differences between organic and biodynamic wines tended to disappear, and the wines were characterized by similar phenolic profiles. Tassoni et al. [43] aimed to compare conventional, organic, and biodynamic white and red grapes and related wines to ascertain whether different agricultural practices directly influence the profiles and contents of bioactive compounds. The contents of polyphenols were measured in white (Pignoletto) and red (Sangiovese) grape berries and wines from the Emilia-Romagna region (Italy) following conventional, organic, and biodynamic agricultural practices. No significant differences were observed for the samples from the different agricultural systems. In our study, compared with the other kinds of wine examined, the wine produced using Syrah grapes contained significantly higher levels of total polyphenol, including total flavonoids. However, in another study [44] on polyphenol compounds in grape berries, Syrah cultivar and wines produced using these grapes through conventional, organic, and biodynamic agricultural methods were compared, and the total anthocyanin content during the ripening of conventionally grown Syrah grapes was significantly higher than that found during organic production.

One of the most important wine phenolic compounds is that of tannins. Condensed tannins are the result of the condensation of flavanols (flavan-3-ols). Epicatechin and their derivatives are the most abundant condensed tannins in grapes and wine, followed by catechin. In addition, they have an important role in the sensory perception of wine’s astringency and bitterness. In the presented study, organic wines contain more tannins compared to conventional ones. This effect was only observed at a significant level for French wines and not Italian ones (Table 3 and Table 5). This was confirmed by Parpinello et al. (2015). They observed a higher concentration of catechin for organic (10.15 mg/L) than for biodynamic (8.8 mg/L) wines as well as of epigallocatechin for organic (5.5 mg/L) than for biodynamic (5.3 mg/L) wines [45]. Cabernet Sauvignon seems to be the richest in tannins compared to Merlot and Syrah. The ranking of wine samples after the analysis of tannin content was as follows: Cabernet > Merlot > Syrah. The experiment presented by Harbertson et al. (2008) using these three kinds of wine confirm our findings [46]. Cabernet Sauvignon was one of the bitterest and most astringent, before Merlot, in terms of sensory evaluation. It seems that a high tannin concentration is a main key for wine taste creation. A trained sensory panel gave higher astringency ratings to high-tannin wines than to low-tannin wines of both varieties, which remained constant throughout the study [47]. The last but not the least feature of wine is color. It is created by piments that belong to anthocyanin group. Wine with a deep, ruby color is more attractive for consumers. In the presented experiment, both French and Italian organic wines were characterized by the highest anthocyanin concentration compared to that of the conventional ones (Table 1 and Table 2). Similar findings were presented by Mullero et al. (2010), with organically produced wines containing 344.7 mg/L of anthocyanins, while conventional ones only contained 296.6 mg/L of anthocyanins [20]. Out of the three evaluated wines, Syrah was characterized by the highest anthocyanin concentration. Opposite results were found by Romero-Cascales et al. (2005). Cabernet Sauvignon and Syrah wines presented the highest wine color intensity and anthocyanin content [48].

Both French and Italian Syrah wines were characterized by a higher content of ethanol (Table 3 and Table 5). The content of alcohol is one of the most important features of wine and can create a wine flavor profile. The first impression in terms of the sensory evaluation of wine is the alcohol odor. As pointed out by Frost et al. (2021), the Syrah wine flavor profile was heavily impacted by increasing the pre-fermentation Brix, which showed higher intensities of astringency, ethanol aroma, and hot mouthfeel compared to those of Cabernet-Sauvignon [7]. Similar findings were pointed out in an experiment with Cabernet Sauvignon and Merlot wines. In the case of the comparison of these two in chemical and sensory ways, French Merlot was evaluated as the wine with a higher concentration of ethanol (12.2% and 12.4%), respectively. At the same time, it was observed that the astringent taste of Merlot wine was more dependent on the content of polyphenolic compounds than alcohol [7]. The acidity of wine depends on the content of the main organic acids as follows: tartaric, acetic, and succinic. The obtained results showed that only Merlot contained much higher tartaric acid compared to Syrah. Volatile acidity was created mostly by the acetic acid content. In presented experiment, a higher concentration of acetic acid was only obtained for Merlot among French wines. For Italian wines, the situation was the opposite. This was confirmed by research conducted by Lasanta et al. (2023) with three wines as follows: Tempranillo, Merlot, and Syrach [49]. A very interesting observation was made for Argentinian Merlot and Syrah wines. In the case of those wines, Syrah was richer in tartaric acid than Merlot [50]. This situation was similar to that of our Italian wines (Table 5).

5. Conclusions

The bioactive compounds found in selected and examined wines have been linked to health benefits in the human body. The present study confirmed that wine method production, both organic and conventional, as well the variety of wine may have a significant impact on the polyphenolic composition of the wine beverages. The organic wines showed a significantly higher concentration of total organic acids, total flavonoids, and total anthocyanins compared to the conventional wines. On the other hand, conventional wines were characterized by a significantly higher concentration of total polyphenols. One of the best varieties of wine was Syrah. The presented results showed the effect of the production system and variety on wine quality, but the continuation of experiments is required to better understand the effect of selected factors on wine quality.