Data on changes in red wine phenolic compounds and headspace aroma compounds after treatment of red wines with chitosans with different structures

Data in this article presents the changes on phenolic compounds and headspace aroma abundance of a red wine spiked with 4-ethylphenol and 4-ethylguaiacol and treated with a commercial crustacean chitin (CHTN), two commercial crustacean chitosans (CHTB, CHTD), one fungal chitosan (CHTF), one additional chitin (CHTNA) and one additional chitosan (CHTC) produced by alkaline deacetylation of CHTN and CHTB, respectively. Chitin and chitosans presented different structural features, namely deacetylation degree (DD), average molecular weight (MW), sugar and mineral composition (“Reducing the negative sensory impact of volatile phenols in red wine with different chitosan: effect of structure on efficiency” (Filipe-Ribeiro et al., 2018) [1]. Statistical data is also shown, which correlates the changes in headspace aroma abundance of red wines with the chitosans structural features at 10 g/h L application dose.


Subject area
Chemistry More specific subject area

Food and Wine Chemistry
Type of data Table,

Experimental features
Chitin and chitosan were analysed by titration, viscosimetry, sugar analysis, X-Ray diffraction and FTIR for their characterization Wine phenolic acids and anthocyanins were analysed by RP-HPLC with a photodiode array detector and headspace aroma abundance were analysed by headspace solid phase microextraction using a 50/30 μm DVB/Carboxen/PDMS fibre followed by GC-MS using an Optima FFAP column (30 m×0.32 mm, 0.25 μm).

Data source location
Vila Real, Portugal

Data accessibility Data with this article
Value of the data • Data presented in this study shows the effect of chitins and chitosans physicochemical characteristics on the phenolic composition, headspace aroma abundance of wines spiked with 4-ethylphenol and 4-ethylguaiacol. • Red wines treated with chitins and chitosans with distinct physicochemical characteristics and application doses (10, 100 and 500 g/h L) were analysed by RP-HPLC to determine the phenolic profile and by HS-SPME-GC/MS to analyse the aroma compounds. • Chitins and chitosans reduced the headspace abundance of 4-ethylphenol and 4-ethylguaiacol of red wine, and the reduction was dependent on the deacetylation degree of chitins and chitosans and on their source (fungal vs crustacean origin). • Increased application doses decreased headspace aroma abundance and phenolic compounds.
• This data could serve as a benchmark for other researchers, evidencing the influence of chitins and chitosans treatment and dose applied on the individual phenolic compounds, chromatic characteristics and headspace aroma abundance of red wine.

Data
The data reported includes information about X-Ray diffraction pattern of chitins and chitosans ( Fig. 1), FTIR spectra (Fig. 2) and band assignments of chitins and chitosans ( Table 1), amount of chitosan dissolved in red wine when applied at 10, 100 and 500 g/h L ( Fig. 3 and Table 2). The headspace aroma abundance of red wines before and after treatment at 10, 100 and 500 g/h L application doses of crustacean (CHTD) and fungal (CHTF) chitosans were determined (Table 3) and the correlation between the headspace aroma compounds abundance reduction with the chitins and chitosans deacetylation degree was calculated (Table 4). Total phenols, flavonoid phenols, non-flavonoid phenols, total anthocyanins, colour intensity, hue and chromatic characteristics of treated and untreated wines were determined (Table 5). Phenolic acids and flavonoids of wines were determined by RP-HPLC (Table 6) and monomeric anthocyanins (Table 7) for 10 g/h L application doses. Total phenols, flavonoid phenols, non-flavonoid phenols, total anthocyanins, colour intensity, hue and chromatic characteristics for red wines before and after treatment with 10, 100 and 500 g/h L application doses of crustacean (CHTD10, CHTD100 and CHTD500, respectively) and fungal (CHTF10, CHTF100 and CHTF500, respectively) chitosans were determined (Table 8). Phenolic acids and flavonoids (Table 9) and monomeric anthocyanins (Table 10) of wines before and after treatment with  10, 100 and 500 g/h L application doses of crustacean (CHTD) and fungal (CHTF) chitosans were determined by RP-HPLC.

Chitin and chitosan samples and production
Commercial crustacean chitin (CHTN, Chitin from shrimp shells, Sigma C9213), two commercial crustacean chitosans (CHTB, Chitosan high molecular weight, Sigma 419419 and CHTD, Chitosan 100000-300000 Da, Acros 34905500) and one fungal chitosan (CHTF, No Brett Inside, Lallemand) where used. One additional chitin (CHTNA) and one additional chitosan (CHTC) were produced by alkaline deacetylation of CHTN and CHTB, respectively [1]. For deacetylation of chitin and chitosan, 15 g of the initial material were dispersed in 150 mL NaOH solution (50% w/v) with NaBH 4 (10 g/L) and heated during 12 h under reflux with stirring, at 130-150°C under nitrogen [10]. For chitin deacetylation, commercial chitin was previously grounded to particles size less than 0.15 mm (obtained by sieving). After cooling to room temperature, the solution was neutralised to pH 6-8 with HCl 12 M and ethanol was added until 75% (v/v) for chitosan precipitation. The precipitate was washed thoroughly with ethanol at 75% (v/v). The material was dried at 50°C in a forced air oven during 24 h.

Chitin and chitosan degree of deacetylation
Chitin and chitosan DD were determined by potentiometric titration [11]. To 200 mg of chitosan, 50 mL of 0.02 mol/L HCl were added and the dispersion was stirred at room temperature during 24 h for obtaining maximum or total solubilisation. The final solution was titrated with previously standardised 0.01 mol/L NaOH and the first and second end-points were determined by  potentiometrically using a pH glass electrode. The DD was determined using the following equation (Eq. (1)): where %DD is the percentage of deacetylation degree, v 1 is the volume, in mL, of NaOH used to neutralize the excess of HCl in solution, v 2 is the volume, in mL, of NaOH used to neutralise the amine groups in chitosan, 161 corresponds to the molecular weight of anhydroglucosamine and m is the quantity, in mg, of chitosan. Analyses were performed in triplicate.

Viscosity average molecular weight of chitosans
The molecular weight and viscosity behaviour of chitosan was determined using Ubbelohde capillary viscometer (N°0B, ASTM-D2515) at 25°C, having a flow time for the solvent used of 195 seconds (t 0 ). Chitosan solutions of different concentrations (0.1 to 1 g/L or 0.4 g/L to 4.0 g/L) in 2% acetic acid, 0.2 mol/L sodium acetate (pH 4.5) solutions were prepared [12]. All the solutions were magnetically stirred for 1 hour in order to ensure proper dissolution of chitosan. The flow times of chitosan solutions and solvent were recorded in triplicate and the average value was calculated. The intrinsic viscosity [η] was calculated graphically by extrapolating the curve of specific viscosity (Eq. (2)) and reduced viscosity (Eq. (3)) versus concentration to zero concentration.
where t 0 is the solvent flow time in seconds, t is the flow time of the chitosan solutions in seconds and C is the concentration of the chitosan solution in g/L. The molecular weight of chitosan was obtained according to the Mark-Houwink equation (Eq. (4)) [12]: where [η] in L/g is the intrinsic viscosity of the polymer, M v is the viscosity average molecular weight of the polymer and K and a are the characteristic constants of the polymer-solvent system (K ¼1.38×10 −5 ; a ¼0.85) [13].  Results expressed in absolute area (area*10 5 ). Values are presented as mean 7standard deviation; $ ID -Identification; Std -Standard; * RI (retention index) from: Vás et al. [4]; Bailley et al. [5]; Czerny et al. [6]. MW (molecular weight). ODT (olfactory detection threshold) and odour descriptor from: Perestrelo et al. [7]; Dragone et al. [8]. Jiang and Zhang [9]. Means within a column followed by the same letter are not significantly different ANOVA and Tukey post-hoc test (p o 0.05). n.d., not detected; Uncontaminated (T0) spiked red wine (TF) and wines treated with chitosans. VPsvolatile phenols. Crustacean chitosan CHTD10 (10 g/h L), CHTD100 (100 g/h L), CHTD500 (500 g/h L) and fungal chitosan CHTF10 (10 g/h L), CHTF100 (100 g/h L) and CHTF500 (500 g/h L).

FTIR analysis of chitins and chitosans
Chitin and chitosan FTIR spectra were recorded in the range of wavenumbers 4000-450 cm −1 and 128 scans were taken at 2 cm −1 resolution, using a Unicam Research Series FTIR spectrometer. Pellets were prepared by thoroughly mixing samples with KBr at a 1:40 sample/KBr weight ratio in a small size agate mortar. The resulting mixture was placed in a manual hydraulic press, and a force of 10 t was applied for 10 min. The spectra obtained were background corrected and smoothed using the Savitzky-Golay algorithm using PeakFit v4 (AISN Software Inc., 1995). Analyses were performed in duplicate.

X-Ray diffraction analysis of chitins and chitosans
Powder X-ray diffraction (XRD) data were recorded on solid samples (chitins and chitosans) using a PANalytical X'Pert Pro X-ray diffractometer equipped with X'Celerator detector and secondary monochromator. The measurements were carried out using a Cu Kα radiation (40 kV; 30 mA) in Bragg-Bentano geometry at 7-60°2θ angular range. Analyses were performed in duplicate.

Experimental design
For studying the effect of DD on chitins and chitosans headspace volatile phenols reduction performance, two chitins and four different chitosans were used at 10 g/h L (CHTN10, CHTNA10, CHTB10, CHTC10, CHTD and CHTF10). The wine was previously spiked at two levels of 4-EP (750 and 1500 µg/ L) and 4-EG (150 and 300 µg/L), named 4-EP750, 4-EP1500, and 4-EG150, 4-EG300, respectively, according to the ranges usually found in the literature [14][15][16]. Chitins and chitosans were added at 10 g/h L, to the wine placed in 250 mL graduated cylinders. For studying the effect of chitosan application dose, the chitosans CHTD and CHTF were also tested in a second trial at 10, 100 and 500 g/ h L (CHTD10, CHTD100, CHTD500, CHTF10, CHTF100 and CHTF500). After 6 days the wine was centrifuged at 10,956g, 10 min at 20°C for analysis. All experiments were performed in duplicate. Table 4 Correlations between headspace abundance of wine aroma compounds and deacetylation degree of chitins and chitosans applied at 10 g/h L.

Table 5
Total phenols, flavonoid phenols, non-flavonoid phenols, total anthocyanins and chromatic characteristics of red wines before (TF) and after treatment with chitins and chitosans with different physicochemical characteristics.

Samples Total phenols
Flavonoid phenols   Table 6 Phenolic acids and flavonoids of red wines spiked with volatile phenols (TF) and after treatment with chitins and chitosans with different physicochemical characteristics.  Table 7 Monomeric anthocyanin composition of spiked red wines (TF) and after treatment with chitins and chitosans with different physicochemical characteristics.    Table 8 Total phenols, flavonoid phenols, non-flavonoid phenols, total anthocyanins and chromatic characteristics of red wines before (TF) and after treatment with chitosans with different physicochemical characteristics and application doses.  Table 9 Phenolic acids and flavonoids of red wines spiked with volatile phenols (TF) and after treatment with chitosans with different physicochemical characteristics and application doses.

Analysis of conventional oenological parameters
The analysis of conventional oenological parameters (alcohol content, specific gravity, pH, titratable and volatile acidity) were analysed using a FTIR Bacchus Micro (Microderm, France).

Headspace wine aroma abundance by solid phase microextraction (HS-SPME)
For the determination of the headspace aroma abundance of red wines a validated method, confirmed in our laboratory was used [4]. Briefly the fibre used was coated with Divinylbenzene/ Carboxen/Polydimethylsiloxane 50/30 μm (DVB/CAR/PDMS) and was conditioned before use by insertion into the GC injector at 270°C for 60 min (Trace GC, Polaris Q MS, Thermo). To a 20 mL headspace vial, 10 mL of wine, 2.5 g/L of NaCl and 50 µL (500 mg/L) of 3-octanol us an internal standard was added. The vial was sealed with a Teflon septum. The fibre was inserted through the vial septum and exposed during 60 min to perform the extraction by an automatic CombiPal system at 35°C. The fibre was inserted into the injection port of the GC during 3 min at 270°C. For separation an Optima-FFAP column (30 m×0.32 mm ID, Macherey-Nigel, Germany) was used. The temperature program was as follows: initial temperature 40°C hold during 2 min, followed by an increase in temperature at 2°C/min to 220°C followed by an increase at 10°C/min to 250°C, hold during 3 min. The flow rate was set at 1.5 mL/min and maintained constant during the run. The transfer line temperature was 250°C and the ion source was set at 220°C. The mass scan was performed between m/z 45 and 650, the scan event was 0.59 s. All analyses were performed in quadruplicate.

Analysis of wine glucosamine content
In the second assay, for quantification of the wine glucosamine content, wines treated with 10, 100 and 500 g/h L of chitosans CHTD and CHTF were performed as follows: to 4 mL of wine, 400 μL of 72% H 2 SO 4 , and the samples were heated at 100°C for 2.5 h. After hydrolysis, 500 μL of 2-deoxyglucose at 1 mg/mL was added as an internal standard and the glucosamine content was determined by anionexchange chromatography using the method described by Ribeiro et al. [17]. Under the conditions of the analytical method the lowest standard in the calibration curve (presenting a signal to noise ratio higher than 10) corresponds to 4.5 mg of anhydrous glucosamine/L of wine. Analyses were performed in quadruplicate.

Quantification of non-flavonoids, flavonoids and total phenols
The wine non-flavonoids content was quantified according to Kramling and Singleton [20]. The results were expressed as gallic acid equivalents by means of calibration curves with standard gallic acid. The total phenolic content was determined according to Ribéreau-Gayon et al. [21]. All analyses were performed in duplicate.

Statistical treatment
The data are presented as means 7 standard deviation. To determine whether there is a statistically significant difference between the data obtained for the diverse parameters quantified in the red wines, an analysis of variance (ANOVA, one-way) and comparison of treatment means were carried out. Tukey honestly significant difference (HSD, 5% level) test was applied to physicochemical data to determine significant differences between treatments. All analyse were performed using Statistica 10 Software (StatSoft, Tulsa, OK U.S.A.).