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Article

The Effect of Seed Removal and Extraction Time on the Phenolic Profile of Plavac Mali Wine

by
Ana-Marija Jagatić Korenika
1,*,
Bernard Kozina
1,
Darko Preiner
1,2,
Ivana Tomaz
1,2,
Josip Volarević
3 and
Ana Jeromel
1
1
Department of Viticulture and Enology, Faculty of Agriculture, University of Zagreb, Svetošimunska Cesta 25, 10000 Zagreb, Croatia
2
Center of Excellence for Biodiversity and Molecular Plant Breeding, Svetošimunska Cesta 25, 10000 Zagreb, Croatia
3
Volarević Winery, Put Narone 124, 20350 Metković, Croatia
*
Author to whom correspondence should be addressed.
Appl. Sci. 2023, 13(9), 5411; https://doi.org/10.3390/app13095411
Submission received: 28 March 2023 / Revised: 14 April 2023 / Accepted: 23 April 2023 / Published: 26 April 2023
Browse Figure
Versions Notes

Abstract

:
The maceration process is one of the indispensable winemaking steps in red wine production that has a marked impact on phenolic compound extraction and can strongly influence the color and gustatory quality. Seed removal can have a substantial impact on the intensity of bitterness and astringency which are mainly influenced by the presence of flavanols. The main aim of this study was to investigate the influence of seed removal and extraction time on the phenolic composition, color parameters, and organoleptic properties of Plavac mali wines produced from the grapes from the Pelješac Peninsula. The achieved results showed that the control wines differ in terms of their highest content of total anthocyanins in both years and total flavonols in one year of investigation, while prolonged maceration without seeds decreases the concentration of phenolic acids as well as that of flavan-3-ols. A prolonged extraction time influenced the color intensity and tonality, moving it towards more yellow pigments. These changes could possibly be explained by the pronounced interaction between phenolic compounds and the formation of the new ones. Interestingly, seed removal probably diminished that change because the potential absorption of the anthocyanins by grape seeds and tannins were excluded. The highest quality was sensory defined in wines produced by prolonged maceration without seeds.

1. Introduction

Grape berry skin and seeds are the main sources of phenolic compounds that are extracted into the wine during the maceration process [1]. The extractability and concentration of these phenolic compounds largely depend on their location in the berry as well as the characteristics of different grape varieties and winemaking steps applied during wine production [2,3]. Hence, their profile is also one of the major determinants of red wine organoleptic quality associated with sensory attributes such as the color, body, bitterness, astringency, mouthfeel, and aftertaste [4].
Phenolic compounds in grapes include the glycosylated and acylated forms of anthocyanins which are mainly responsible for the wine color and flavanols (which include flavan-3-ol monomers and proanthocyanidins), also known as tannins, which are responsible for wine gustatory characteristics as well as tactile sensation of astringency [5]. Anthocyanins are extracted from the skin by diffusion and their concentrations usually decrease after several days of contact when the rate of anthocyanins undergoing various condensation reactions exceeds the extraction rate [6]. As reported by [7] and proved by many published data, the highest color parameters and anthocyanin levels are obtained in wine macerated for three to six days, while during prolonged maceration time the wine color intensity decreases. The main Vitis vinifera varieties of anthocyanins are delphinidin, cyanidin, petunidin, and malvidin mono glucosides, and the acylated derivatives with acetic, p-coumaric, and caffeic acids [8].
The extraction rate of skin and seed flavanol compounds defer as most skin proanthocyanins due to their location and are solubilized and extracted in the first days of maceration. Whereas, the extraction of seed proanthocyanins requires a longer maceration time and is triggered in the presence of ethanol [2]. According to [9], flavanol monomers such as epicatechin-3-O-gallate, galocatechin, and catechin; dimers such as procyanidins B1, B2, B3, and B4; and trimers such as procyanidins C1 are mostly being associated with the perception of bitterness, while the presence of tannins and certain flavonols has been linked with astringent sensation. However, a bitter taste can be caused also by particular flavonols and hydroxycinnamates as well as benzoic acids and their derivatives [10].
The maceration process, as one of the necessary winemaking steps in red wine production, can have a marked impact on phenolic compound extraction by varying the duration and temperature [11]. Generally, the contact of grape solids with the must is related to the length of the prefermentative phase and the duration of alcoholic fermentation which usually lasts for 7 to 15 days after the crushing. In the case of extended or prolonged maceration, the contact time of the grape solids with wine can vary between 30 days to 2 months [5,11]. The main difference compared to classic maceration time is the higher tannin solubility, especially from seeds whose outer lipid cuticle is disrupted by the presence of ethanol and excessive time which enables them to fully hydrate and collapse [12,13]. Thus, from the sensory point, prolonged maceration can decrease the color and increase the bitterness and astringency, mainly correlating with monomeric flavan-3-ols and oligomeric tannins in higher concentrations [14,15]. However, a longer maceration period is not always connected to an increase in phenolic concentration possibly due to their interaction with cell wall polysaccharides whose presence is linked with continuous depectination of the berry pomace [16]. The influence of early grape seed removal was reported by [17] showing higher concentrations of total anthocyanins and minor differences in color measurement values. Seed removal in Monastrell wine production positively influenced the overall quality [18].
Among the red grape varieties being cultivated in Croatia, Plavac mali is the most planted: it covers an area of 142,662 ha [19] and has a high potential for producing exceptional wines. As it is a late-ripening variety, to obtain high-quality wines it requires growing sites with a long vegetation period typical for southern parts of Dalmatia, especially the islands of Hvar, Korčula, Vis, and the Pelješac Peninsula. Plavac mali wine has already been singled out as that with the most specific phenolic composition as well as less intense coloration and an accentuated but pleasant astringency when compared to other monovarietal wines produced in Croatia [20]. On the other hand, in the years with unfavorable agroclimatic conditions the pronounced bitterness and astringency can have a negative effect on the overall quality of Plavac mali wine as a result of phenolic compound extracted from seeds that were not able to reach full maturity.
The main aim of this study was to investigate the influence of seed removal and extraction during the prolonged maceration on the phenolic composition, color parameters, and organoleptic properties of Plavac mali wines.

2. Materials and Methods

2.1. Vineyard Location

Plavac mali grapes used for vinification in this research were produced in the Dalmatia wine region in southern Croatia on the wine-growing area Rota in the interior of the Pelješac Peninsula. The wine-growing position is south-orientated at 350 to 480 m above the sea level and is characterized by the soil obtained from the cast reclamation with a high share of stone fraction on the medium steep slope.

2.2. Fermentation Trials

Regarding the vintages of 2014 and 2015, 75 kg of Plavac mali grapes were manually harvested and transported to the winery near the vineyard. The basic chemical composition of the Plavac mali 2014 was the following: initial sugar 225 g/L, total acidity as tartaric acid 6.55 g/L, and pH 3.15. As for the Plavac mali 2015 it was: initial sugar 254 g/L, total acidity as tartaric acid 6.10 g/L, and pH 3.25. The noted differences between the investigated years is the result of extremely high temperatures in the year 2015 resulting in higher sugar content and lower acidity, a well-known pattern also presented in the work by [21]. The total grape amount was divided into five different treatments (5 × 15 kg) and each amount was destemmed, crushed separately, and distributed evenly into 20 L stainless steel fermenters. In the two treatments, approximately 85–90% of the seeds (between 480 and 500 g/15 kg of grapes) were removed. Immediately after crushing, the mash was treated with 5 mg/L of potassium metabisulfite (AEB SPA Brescia, Italy). Each mash was inoculated with 3 mg/L of rehydrated dry yeast Saccharomyces cerevisiae (Lalvin ICV D254®, Lallemand Inc., Canada). The yeast strain was added at approximately 1 × 107 cells/mL and fermentations were carried out at 20 °C according to the manufacturer’s instructions. The cell concentrations (haemocytometry) and viability (methylene blue staining) were determined under a light microscope. The addition of 10 mg/L of yeast supplement (Fermaid E®, Lallemand Inc., Canada) followed on the second and the fifth day of fermentation. Each treatment was conducted in three replicates. The course of fermentation was monitored by analyzing the sugar consumption rate and it was considered complete when the residual sugar concentrations were under 4.0 g/L. In all variants, fermentation started 24 h after inoculation and lasted between 10–12 days. In that period, kinetic fermentation determined by the decomposition of sugars showed no marked difference. The control treatment implied standard seven day long maceration while the others were different prolonged maceration treatments as follows:
A
control treatment, 7 day maceration
B
21 day maceration
C
49 day maceration
D
21 day maceration with seed removal
E
49 day maceration with seed removal
During the maceration period, the cap was punched down manually three times a day. Once maceration was finished, the wines were pressed and placed in the 10 L-glass containers until the end of alcoholic fermentation where needed (reducing sugars to less than 4 g/L). The final wines were bottled in 750 mL glass bottles with screw caps and transported to the laboratory of the Department of Viticulture and Enology and the Faculty of Agriculture of the University of Zagreb for further chemical and instrumental analysis. The basic physicochemical analysis (ethanol content, titratable acidity, volatile acidity, and pH) showed no marked differences between treatments in both the experimental years.

2.3. Phenol Compound Determination

The analysis of the phenolic compounds was conducted on the HPLC system Agilent 1100 Series (Agilent, Waldbronn, Germany) according to the method described by Tomaz and Maslov [22]. In brief, the filtration of wine samples was performed by Phenex PTFE 0.2 μm syringe filters (Phenomenex, Torrence, CA, USA). Reverse-phased column Luna Pheny-Hexyl heated at 50 °C was handled for the separation. The composition of mobile phases was as follows: mobile phase A H2O:H3PO4 (99.5:0.5, v/v) and mobile phase B H2O:H3PO4:CH3CN (49.5:0.5:50, v/v/v). The flow rate and the injection volume were 0.9 mL/min and 20 μL, respectively. The detection of hydroxybenzoic acids, hydroxycinnamic acids, flavonols, and anthocyanins was conducted at 280, 320, 360, and 518 nm, respectively, while flavan-3-ols were detected at λex/λem = 225/320 nm.

2.4. Color Parameters

When directly reading the absorbance at 420, 520, and 620 nm, the following color parameters were analyzed: the color intensity (CI), hue/tint/tonality (T), and proportion of blue (% Bl), red (% Rd), and yellow (% Ye). The measurement of absorbance was performed on the spectrophotometer Lambda XLS (PerkinElmer, Waltham, MA, USA). The calculation of the above-mentioned parameters was conducted according to the previously published equations [23]. The wine color intensity (CI) was calculated by addition of A420 + A520 + A620, color tonality (T) by division of A420/A520 while the chromatic structure, i.e., the contribution in percentage for each of the three components was calculated as follows: % Yellow = A420/CI, % Red = A520/CI, and % Blue = A620/CI.

2.5. Sensory Analysis

Seven experts (three women and four men), who are members of the “Committee for Organoleptic Evaluation of Wine and Fruit Wines” assigned by the Ministry of Agriculture, conducted the sensory analysis of Plavac mali wines. All of them are specialists in the field and well-experienced in sensory analysis of Plavac mali wines. For quality assessment, the quantitative descriptive analysis (QDA) experiment of random blind tasting by three replicates was used. Before starting the tasters, they each attuned their taste descriptor intensity and overall taste score criteria by tasting three Plavac mali wine samples. Samples were coded and served in a random order. For the color attribute (color saturation), taste differences (sweetness, bitterness, and acidity), and mouthfeel sensation (astringency and aftertaste intensity), a five-point structured evaluation scale on a paper sheet was used (0—not perceptible to 5—strongly perceptible). The evaluation of the data was performed by one-way variance (ANOVA) and based on this analysis the distinctions and significance between evaluated samples were numerically presented. For the overall sensory quality assessment of Plavac mali wines, a ranking test was performed. In the ranking test, wines were ranked in descending order of preference; value 1 was assigned to the most preferred wine, value 2 to the next most preferred wine, and value 5 to the least preferred wine. Following this the obtained ranking results were converted to normal scores [24] which were used for statistical analysis (ANOVA).

2.6. Statistical Analysis

ANOVA was used to test the significance of the effects of maceration/fermentation treatments separately for two years of study on all analyzed parameters. In case of significant results obtained by ANOVA, the means were compared using Duncan’s multiple range test. Principle component analysis (PCA) was used to evaluate the total variability in polyphenolic profiles of wines from different maceration/fermentation treatments from two years of study. Variables and observation scores for the first two canonical factors were used to create scatter plots to explain multivariate differences among samples. All of the analyses were carried out using XLSTAT software v.2020.3.1. (Addinsoft, New York, NY, USA).

3. Results and Discussion

3.1. Plavac Mali Wines’ Phenolic Profile

In Table 1, the phenolic profile of Plavac mali wines from two experimental years is presented by 17 compounds from different chemical groups such as anthocyanins, phenolic acids, flavan-3-ols, flavonols, and stilbenes. It is evident that the impact of different prolonged maceration times and seed removal on the individual phenolic concentrations was present regardless of the research year even though the phenolic profile between the years was different. Grape development and maturation is highly dependent on annual climate variations and consequently is the wine chemical profile [25]. Recent research by [26] has shown that climate has a significant impact on grape quality and on the synthesis of phenolic compounds between years. Hence, it is obvious that in this research the impact of the year on the grape and wine phenolic profile was also present.

3.1.1. Anthocyanins

It is well known that anthocyanins are one of the most important bioactive compounds and have a strong influence on wine color intensity and antioxidant activity [27]. The significant contribution of anthocyanins to antioxidant capacity as well as a proportional correlation between the quantitative content of wine anthocyanins and antioxidant activity was shown in work by [28,29]. As expected and in accordance with data in the literature [30,31], the most represented anthocyanin was malvidin-3-O-glucoside followed by delphinidin-3-O-glucoside. Presented results are partly in accordance with published data, suggesting that longer maceration times decrease anthocyanin concentrations by their degradation and/or transformation to other chemical compounds [2,3,7]. As already posted in the paper [32], the maximum concentrations of total anthocyanins in Plavac mali wines were obtained after 8 days followed by a significant decrease after 17 days. In this research, the highest concentrations were also achieved after 7 days followed by a pronounced decrease after 21 days and no marked differences after 49 days of maceration. The same pattern was noticed between variants D and E (21 and 49 day macerations with seed removal). Even though in the work by [14,18] seed removal did not cause any important total anthocyanins differences, these results showed that the combination of prolonged maceration time with seed removal regardless of the duration time had an additional effect on the anthocyanin concentration decrease, mainly malvidin-3-O-glucoside. This result pointed out a significant impact of seed tannins in the preservation of monomeric anthocyanins, as shown in the work by [33] where wines supplemented either with a commercial seed tannin solution or fermented seeds had higher tannin and monomeric anthocyanin concentrations than the untreated wine. Even though the concentration of anthocyanins was much higher in the year 2014, as can be seen from Table 1 the impact of maceration time and seed removal on the decrease of anthocyanins was noted in both experimental years. Extremely high temperatures in Dalmatia in 2015 with several heat waves (max temp. higher than 38 °C) [34] against relatively moderate (average) temperatures in 2014 resulted in significantly lower total anthocyanins in wines from all treatments (as well as other groups of phenolic compounds). This corresponds other research suggesting that this is a result of the inhibition and reduced enzymatic activity in grapes related to the synthesis of anthocyanins [35] as well as other phenolic compounds [36].

3.1.2. Phenolic Acids

The main phenolic acidic groups present in wines are hydroxybenzoic and hydroxycinnamic acids in either the free or conjugated form. Among benzoic acids, a similar pattern, as already shown in the work by [37] was defined, namely with gallic acid as the predominant one followed by trans-caftaric acid whose concentrations were, as shown in Table 1, more influenced by seeds removal than maceration time. In the work published by [38], prolongation of the maceration time from 5 to 15 days resulted in higher levels of phenolic acids that can be, according to [39], ascribed to the hydrolysis of their esters, which was not so emphasized in this research. One of the reasons could be the further interaction of individual acids with other compounds, possibly a copigmentation reaction with anthocyanins as reported by [40,41,42]. Thus, longer maceration times may increase the extraction of seed phenolics, especially gallic acid whose higher concentrations could be connected with the richness of grape seeds in gallic acid [43] even though according to [16] longer maceration times did not always correspond to an increase in wine phenolic concentration. As evident in Table 1, the presented results pointed out a stronger influence of seed removal than maceration time on gallic as well as trans-caftaric acid concentrations being lower when compared to the variants where seeds were present. It can be related to their strong antioxidant function which was more pronounced in the variants without seeds, where the flavonoid antioxidant action was diminished [27].

3.1.3. Flavan-3-ols

The total flavan-3-ol concentration was strongly influenced by the extraction time and seed removal with the highest concentrations achieved by 49 and 21 days of prolonged maceration followed by 49 days of prolonged maceration without seeds. These data are in accordance with earlier studies [11,44,45] showing a positive influence of longer maceration times on primarily (+)-catechin, procyanidin B2, and (−)-epicatechin-gallate. Interestingly, the smallest difference was noted in the concentration of (+)-gallocatechin and procyanidin B1 whose presence, as reported by [45], are exclusively connected to grape skins and seeds removal thus had no marked effect. On the other hand, the (+)-catechin, procyanidin B2, and (−)-epicatechin-gallate concentrations were much lower in the variants where seeds were separated, proving that their absence can strongly influence the phenolic profile of wines. This corresponds to the previously published data [12,45,46] showing that a greater relative proportion of individual flavan-3-ols existed in the seeds. Moreover, data presented in this work correspond to those previously published results [32] pointing out Plavac mali variety as one with a large share of flavan-3-ols placed in the skin from which they are readily extracted and which, in this case, resulted in more or less equal levels in wines produced with 7 day maceration times compared to prolonged maceration wines with seed removal (Table 1). The impact of the year was not pronounced which is in accordance with work by [47] pointing out that temperature and thermal increases have little impact on tannins whose accumulation in skins and seeds occurs predominantly before veraison [48].

3.2. Color Parameters

Table 2 shows Plavac mali wines’ color parameter results such as color intensity (CI), color tonality (T), and proportion of yellow (% Yellow), red (% Red), and blue (% Blue) pigments. Even though it is well known that the content of anthocyanins and their profile is responsible for wine color, nowadays it is apparent that copigmentation is a very notable contributor to the color of young red wines. Copigmentation in wine is mainly connected with the interactions between anthocyanins and a variety of organic molecules such as phenolic acids, flavonols, flavan-3-ols, and even anthocyanins themselves [42,49]. According to results presented in Table 2, a 49 day maceration period strongly influenced the color profile of wines by moving it towards more yellow pigments that could be explained by a pronounced interaction between phenolic compounds and the formation of new ones. Interestingly, that change was diminished with seed removal, as presented in Table 2, and no significant differences were noted in the red and yellow pigments between seed removal wines (variants D and E) and 21 day maceration wines (variant B). It can be seen that the effect of applied seed removal and maceration time was the same in both years even though the phenolic profile of tested wines differed showing that the initial grape chemical composition was not decisive.

3.3. Sensory Analysis

Sensory analysis results presented in Table 3 show marked differences in descriptive attributes between treated Plavac mali wines. The highest color intensity was noted in control and 7 day maceration treatment wines, which is in accordance with the color data presented in Table 2. Moreover, as presented by [50], seed removal had a significant impact on color intensity, but only when compared to control treatment wines. A positive effect on sweetness, as well as aftertaste intensity, was noted in prolonged maceration with and without seed treatments while the acidity taste was less emphasized compared to control and 21 day maceration wines. Data published by [11,51] also pointed out that the prolonged maceration technique can be used to positively alter the mouthfeel of the wine, mainly connected with proanthocyanidin extraction and polymeric pigment formation. The greatest difference was detected in the bitterness and astringency sensation being less intense in Plavac mali wines macerated without seeds: the results are in accordance with [18,52] but are contrary to [17], where control wines compared to early seed removal wines were preferred. Eventually, the ranking test was conducted to define the expert’s affinity among the wines. The experts’ task was to rate the samples based on their overall impression. Lower scores corresponded to higher preference. The results presented in Table 4 clearly show the superior quality of prolonged maceration with seed removal. According to statistical analysis using the conversion of ranking results to normal scores, it is evident that treatment E in both years and treatment D in 2015 (both prolonged macerated wines with seed removal) were significantly better in comparison to the other ones [53].

3.4. Multivariate Analyses

Based on the results of Principle Components Analyses (PCA) performed using average polyphenol profiles of wines obtained by different maceration treatments (Figure 1) it was possible to see apparent differences among them. Based on the distances among treatments on the scatter plot and the related vector diagram of polyphenolic compounds, we can conclude that in both years of study, wines from the control treatment differed in terms of the highest content of total anthocyanins and total flavonols but also regarding some other compounds (i.e., gallic acid). In addition, 21 and 49 day prolonged macerations showed distinct phenolic profiles depending on the presence/absence of seeds in both years of the study. Based on the position of both prolonged macerations without seeds, it is evident that they had a lower content of all polyphenolic compounds, while wines obtained from prolonged macerations with seeds showed a higher content of seed-specific polyphenols.

4. Conclusions

Based on the presented results, it seems that the implementation of 21 and 49 day prolonged maceration combined with early seed removal has a positive impact on the taste quality of Plavac mali wines by manipulating phenolic acid and flavan-3-ol concentrations and at the same time having no negative impact on color intensity and tonality. As mentioned above, Plavac mali wines, especially if they are not properly aged, can be very bitter and astringent which can have a negative impact on the overall quality. The achieved results have shown that more pronounced phenolic profile changes, as well as taste differences, will occur by early seed removal compared to the maceration time. Thus, the obtained results could help wine producers in making their decisions about which vinification method to choose in terms of the production conditions and available resources.

Author Contributions

Conceptualization, A.-M.J.K. and J.V.; methodology, I.T.; formal analysis, I.T.; data curation, D.P.; writing—original draft preparation, A.-M.J.K.; writing—review and editing, A.-M.J.K. and B.K.; supervision, A.J. All authors have read and agreed to the published version of the manuscript.

Funding

The publication was supported by the Open Access Publication Fund of the University of Zagreb Faculty of Agriculture.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Not applicable.

Conflicts of Interest

The authors declare no conflict of interest.

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Applsci 13 05411 g001 550
Figure 1. The scatter plots represent the differences in polyphenolic profiles of Plavac mali wines from two years of study produced using different maceration treatments (A—control treatment, 7 days maceration, B—prolonged maceration, 21 days, C—prolonged maceration, 49 days; D—prolonged maceration without seeds, 21 days, E—prolonged maceration without seeds, 49 days) based on PCA and the related vector diagram of polyphenolic compounds contributing to the differentiation.
Figure 1. The scatter plots represent the differences in polyphenolic profiles of Plavac mali wines from two years of study produced using different maceration treatments (A—control treatment, 7 days maceration, B—prolonged maceration, 21 days, C—prolonged maceration, 49 days; D—prolonged maceration without seeds, 21 days, E—prolonged maceration without seeds, 49 days) based on PCA and the related vector diagram of polyphenolic compounds contributing to the differentiation.
Applsci 13 05411 g001
Table
Table 1. Phenolic profile of Plavac mali wines.
Table 1. Phenolic profile of Plavac mali wines.
Compounds (mg/L)TPTTaste DescriptorsABCDEABCDE
2014 Year2015 Year
Delphinidin-3-O-glucoside 29.31 a30.71 a30.74 a25.11 b24.34 b15.90 a12.52 b11.73 bc9.90 c9.99 c
Petunidin-3-O-glucoside 9.87 b11.94 a12.11 a9.35 b8.35 c7.16 a5.62 b5,58 b3.08 c5.31 b
Peonidin-3-O-glucoside 2.69 c3.61 a3.46 a3.10 b3.54 a1.74 a1.42 b1.30 bc1.61 ab1.28 c
Malvidin-3-O-glucoside 193.30 a111.32 b109.31 b82.84 c81.75 c80.24 a67.38 b61.98 c45.31 d42.76 d
Ʃ Anthocyanins 235.17 a157.58 b155.62 b120.04 c117.98 c105.04 a85.94 b80.59 c59.90 d59.34 d
Miricetin-3-O-glucoside 2.91 ab3.20 a1.92 c2.66 b2.08 c1.03 a0.85 b0.78 b0.84 b0.87 b
Quercetin-3-O-glucoside 7.20 a7.86 a3.89 b3.32 c3.93 b2.36 a1.55 b0.88 c0.56 d1.08 c
Ʃ Flavonols 10.11 a11.06 a5.81 b5.98 b6.01 b3.40 a2.40 b1.66 cd1.39 d1.94 c
trans-caftaric acid5Puckering
astringent		33.85 b38.87 a30.21 c24.47 d20.06 e27.83 a26.87 b21.33 c16.29 d16.20 d
Caffeic acid13Puckering
astringent		4.55 b5.14 a4.57 b4.62 b4.21 b3.80 a3.70 a3.35 b3.27 bc3.01 c
trans-coutaric acid10astringent11.07 b12.76 a10.29 c7.71 d6.05 e9.96 a9.52 a7.15 b4.88 c4.92 c
trans-coumaric acid23Puckering
astringent		1.77 a1.48 b1.73 a1.54 ab1.80 a2.72 c2.96 b3.36 a3.09 b2.76 c
Gallic acid50Puckering
astringent		62.11 a60.33 a65.78 a56.39 b56.89 b47.25 a48.09 a48.92 a27.35 b28.08 b
Ʃ Phenolic acids 113.35 a118.58 a112.58 a94.73 b89.01 b91.56 a91.14 a84.11 b54.88 c54.97 c
(+)-Gallocatechin 3.11 bc4.15 a3.31 b3.49 b2.93 c2.01 a1.96 a1.60 b1.91 a1.64 b
Procyanidin B1139/231Bitter/astringent6.93 ab7.71 a7.75 a7.52 a6.57 b4.87 a4.51 c4.80 ab3.96 d4.62 bc
(+)-Catechin119/290Puckering
Astringent/bitter		24.96 d45.52 b73.48 a24.71 d33.80 c24.15 d34.72 b50.08 a25.30 d31.59 c
Procyanidin B2110/280Bitter/astringent12.41 d30.84 b54.22 a13.65 d19.54 c12.70 e23.32 b39.15 a15.53 d19.83 c
(−)-Epicatechin-gallate 4.60 b7.20 a7.23 a3.68 c4.11 b3.56 c4.67 b5.02 a3.63 c3.84 c
Ʃ Flavan-3-ols 52.01 d95.42 b145.99 a53.05 d66.95 c47.28 d69.17 b100.66 a50.32 d61.52 c
Resveratrol-O-glucoside 9.55 b12.09 a9.72 b8.38 c5.71 d5.64 a5.73 a4.84 b3.44 d4.01 c
Values are presented as average concentrations of three replicates. Taste perception thresholds (TPT; mg/L) and taste descriptors reported in the literature [2]. Means with different superscript letters (a, b, c, d, e) for each year separately, in the same row differ significantly (p ≤ 0.05). Treatments (A—control treatment, 7 day maceration; B—21 day maceration; C—49 day maceration; D—21 day maceration with seed removal; E—49 day maceration with seed removal).
Table
Table 2. Color parameters of Plavac mali wines.
Table 2. Color parameters of Plavac mali wines.
YearTreatmentA420A520A620CITChromatic Structure
% Yellow
Pigments		% Red
Pigments		% Blue
Pigments
2014A2.433.690.516.63 a0.65 c36.65 c55.65 a7.69 c
B2.453.450.526.42 c0.71 b38.16 b53.73 b8.09 b
C2.813.230.556.59 b0.86 a42.64 a49.01 c8.34 a
D 2.483.340.536.35 c0.74 b39.05 b52.59 b8.35 a
E2.463.310.526.29 c0.74 b39.10 b52.62 b8.26 a
2015A2.023.050.485.55 a0.66 b36.39 c54.95 a8.64 c
B2.032.980.505.51 b0.68 b36.84 c54.08 a9.07 b
C2.192.770.515.47 b0.79 a40.03 a50.63 c9.32 a
D2.052.860.505.39 c0.71 b38.03 b53.06 b9.27 a
E2.102.870.505.47 b0.73 b38.39 b52.47 b9.14 a
CI—color intensity, T—color tonality, A420, A520, A620 - absorbances at 420, 520, and 620 nm. Concentrations expressed as mean values (n = 3). Means with different superscript letters (a, b, c), for each year separately, in the same column differ significantly (p ≤ 0.05). Treatments (A—control treatment, 7 day maceration; B—21 day maceration; C—49 day maceration; D—21 day maceration with seed removal; E—49 day maceration with seed removal).
Table
Table 3. Quantitative descriptive analysis (QDA) results of Plavac mali wines.
Table 3. Quantitative descriptive analysis (QDA) results of Plavac mali wines.
YearTreatmentColor
Saturation		SweetnessBitternessAcidityAstringencyAftertaste Intensity
2014A3.85 a2.00 b4.23 b2.33 a3.95 a3.05 bc
B3.57 b2.00 b4.33 b2.18 b3.85 b2.95 c
C3.54 b2.14 a4.81 a2.23 a3.71 b3.57 a
D 3.61 b2.16 a3.71 c2.19 b3.13 c3.23 b
E3.56 b2.09 a3.56 d2.18 b3.14 c3.56 a
2015A3.38 a1.95 a3.54 b2.28 a3.37 a2.85 b
B2.95 b2.00 a3.57 ab1.85 b3.18 b2.95 b
C3.05 b1.99 a3.61 a1.99 b3.23 ab3.18 a
D3.04 b1.88 a3.37 c1.95 b3.04 c3.19 a
E3.13 b2.00 a3.49 b1.95 b3.13 bc3.00 b
Values are presented as the average score of three replicates. Means with different superscript letters (a, b, c) for each year separately, in the same column differ significantly (p ≤ 0.05). Treatments (A—control treatment, 7 day maceration; B—21 day maceration; C—49 day maceration; D—21 day maceration with seed removal; E—49 day maceration with seed removal).
Table
Table 4. ANOVA of normalized ranking test results of Plavac mali wines.
Table 4. ANOVA of normalized ranking test results of Plavac mali wines.
TreatmentYear
20142015
E1.004 a0.830 a
D0.630 b0.679 a
A−0.308 c−0.079 b
B−0.489 c−0.536 c
C−0.838 d−0.893 d
Values are presented as the average of the normalized score three replicate of seven expert scores. Treatments (A—control treatment, 7 day maceration; B—21 day maceration; C—49 day maceration; D—21 day maceration with seed removal; E—49 day maceration with seed removal). Means with different superscript letters (a, b, c, d) for each year significantly separately differ (p ≤ 0.05).
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Jagatić Korenika, A.-M.; Kozina, B.; Preiner, D.; Tomaz, I.; Volarević, J.; Jeromel, A. The Effect of Seed Removal and Extraction Time on the Phenolic Profile of Plavac Mali Wine. Appl. Sci. 2023, 13, 5411. https://doi.org/10.3390/app13095411

AMA Style

Jagatić Korenika A-M, Kozina B, Preiner D, Tomaz I, Volarević J, Jeromel A. The Effect of Seed Removal and Extraction Time on the Phenolic Profile of Plavac Mali Wine. Applied Sciences. 2023; 13(9):5411. https://doi.org/10.3390/app13095411

Chicago/Turabian Style

Jagatić Korenika, Ana-Marija, Bernard Kozina, Darko Preiner, Ivana Tomaz, Josip Volarević, and Ana Jeromel. 2023. "The Effect of Seed Removal and Extraction Time on the Phenolic Profile of Plavac Mali Wine" Applied Sciences 13, no. 9: 5411. https://doi.org/10.3390/app13095411

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