Evaluation of antioxidant and sensory properties of mango (Mangifera indicaL.) wine

Abstract

This investigation deals with the antioxidant and sensory properties of mango wine produced from different mango varieties. The highest phenolic content was recorded in wines produced from Alphonso(537 mg/l), Banginapalli(456 mg/l) and Sindhoora(490 mg/l) mango fruit varieties. The antiradical activity varied from 27.57% to 36.70% ascorbic acid equivalents, the antioxidant activity varied from 73.90% to 85.95% gallic acid equivalents and the reducing power varied from 0.71 to 2.90 μm/l ascorbic acid equivalents. From the liquid chromatography–mass spectrometer (LC–MS) analysis, 11 phenolic compounds were identified in Alphonsowine. Based on nine-point hedonic scale for the evaluation of organoleptic properties, the wines made from Alphonsoand Banginapallivarieties have been found to have better sensory properties. A significant correlation was not observed between the panellist and the instrumental results.

La presente investigación trata sobre las propiedades antioxidantes y sensoriales del vino de mango producido con diferentes variedades. El contenido más alto de fenólicos se registró en vinos producidos con variedades de mango Alphonso(537), Banginapalli(456) and Sindhoora(490 mg/l). La actividad antiradical varió entre 27,57 y 36,70% equivalentes de ácido ascórbito, la actividad antioxidante entre 73,90 y 85,95% equivalentes de ácido gálico y el poder reductor entre 0,71 y 2,90 μm/l equivalentes de ácido ascórbico. Del análisis LC–MS se identificaron once components fenólicos en el vino elaborado con Alphonso. Basándose en la escala hedónica de nueve puntos para la evaluación de las cualidades organolépticas, los vinos producidos con las variedades Alphonsoy Banginapalliresultaron tener mejores propiedades sensoriales. No se observó una correlación significativa entre los resultados de panelistas e instrumentales.

Keywords:

• mango wine
• phenolic compounds
• antioxidant activity
• sensory evaluation

Palabras clave:

• vino de mango
• componentes fenólicos
• actividad antioxidante
• evaluación sensorial

Introduction

Mango (Mangifera indicaL.) is one of the important tropical fruits cultivated in many tropical regions and distributed widely in the world. Mango fruits are highly perishable, with a shelf life of 2–4 weeks at 10–15°C (Yahia, 1998), limiting their availability in fresh at markets. One of the methods for processing and preserving mango is to ferment the juice, which has high carbohydrate content into wines. Onkarayya and Singh (1984) screened 20 varieties of mango fruits that are available from India for wine production. Obisanya, Aina, and Oguntimei (1987) studied the fermentation of mango juice into wine using locally isolated Saccharomyces cerevisiaeand Schizosaccharomycesspecies of palm wine. From the physico-chemical characteristics of the mango wine produced, it was observed that aromatic components were comparable in concentration with those of grape wine and sensory evaluation scores of wine correlated to the sum of higher alcohols (Reddy & Reddy, 2009).

Red wine has been reported to be more protective against coronary heart disease than other alcoholic beverages (Gronbaek et al., 1995). Wine composition, including the contents of phenolic compounds, varies markedly depending on the grape cultivar, soil, nutrition, climatic conditions, weather, winemaking procedure and conditions of maturation and storage. Over 500 different compounds, of which 160 are esters, have been identified in different wine types. Phenolic compounds considered being basic components of wines and over 200 compounds have been identified. Two primary classes of phenolics that occur in grapes and wine are flavonoids and nonflavonoids. The most common flavonoids in white and red wines are flavonols, catechins (flavan-3-ols) and anthocyanidins, the latter being found only in red wine. Small amounts of free leucoanthocyanins (flavan-3,4-diols) also occur. Flavonoids exist free or bound to other flavonoids, sugars, nonflavonoids or combinations of these compounds. Flavonols and anthocyanidins originate predominately from the skin, whereas catechins and leucoanthocyanins originate mainly from the seeds and stems. Nonflavonoids partly originate from yeast and the wood of oak barrels (Soleas, Tomilinson, Diamandis, & Goldberg, 1997).

Phenolic compounds increase under environmental stress, playing a vital role in plant survival. Recent awareness of the role of antioxidants plays in the promotion of health, due to their ability to act as chemoprotective agents (Teissedre & Waterhouse, 2000). Wine polyphenols contribute to wine colour and to other sensorial characteristics of wines such as bitterness and astringency (Perez-Magarino & Gonzalez-Sanjose, 2004). Not all phenolic compounds possess the same biological activity, and their composition in wines can be strongly affected, not only quantitatively, but also qualitatively by grape cultivar, maturity degree of the grapes used, environmental factors, wine-making techniques and technological treatments (Cimino, Sulfaro, Trombetta, Saija, & Tomaino, 2007).

In view of the foregoing and importance of phenolic compounds as antioxidants in wine, the present investigation has been undertaken to identify the antioxidant properties and to evaluate the sensory properties of mango wine.

Materials and methods

Materials

Eight varieties of mango fruits (Alphonso, Banginapalli, Raspuri, Neelam, Himami pasand, Rumani, Totapuriand Sindhoora) were obtained from the local mango fruit market of Tirupati (India). Diammonium salt of the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic) acid (ABTS), potassium persulphate, 2,2-diphenyl-2-picrylhydrazyl (DPPH), gallic acid and 2,4,6-tripyridyl-S-triazine (TPTZ) were purchased from Sigma-Aldrich (St. Louis, MO, USA). Folin and Ciocalteu phenol reagent, Na₂CO₃and chemical solvents were obtained from SD-Fine Chemicals (Mumbai, India).

Mango wine production

The mango pulp from eight varieties was treated individually with 0.3% (w/v) of pectinase. The juice was extracted and subjected to analysis of sugars (total and reducing), total acidity, pH and soluble solid contents. It was stored at 4°C prior to fermentation. Saccharomyces bayanus, a wine yeast culture, was kindly gifted by Prof. Roberto Ambrosoli, University of Turin, Italy, and an inoculum of (3 × 10⁶cells/ml) was used for wine fermentation. The mango wine fermentation was carried out with the optimized conditions described by Kumar, Prakasam, and Reddy (2009). After fermentation, the wine was filtered using cheese cloth and stored at 4°C for further evaluation. The physico-chemical characteristics of mango wines were determined according to Kumar et al. (2009), and residual sugars were determined spectrophotometrically using 3,5-dinitrosalicylic acid (DNS) method. Total acidity was determined by titrating with 0.1 N NaOH previously standardized using standard oxalic acid, and the values were expressed as gram per litre (g/l) of tartaric acid and volatile acidity in the distillate samples are expressed as g/l of acetic acid. Ethanol and other major volatiles (higher alcohols and esters) were determined by gas chromatography after the completion of the fermentation in cell-free samples obtained by centrifugation at 5000 × gfor 10 min (Reddy & Reddy, 2009).

Determination of total polyphenolic contents by Folin–Ciocalteu method

The total phenolic contents were determined spectrophotometrically according to the Folin–Ciocalteu reagent (Singleton, Orthofer, & Lamuela-Raventos, 1999). Samples of wine (1 ml) were diluted with distilled water (4 ml). Then, an aliquot (0.2 ml) of diluted wine and 1 ml of Folin–Ciocalteu reagent were mixed into a 20-ml calibrated flask. After 1 min, 4 ml of Na₂CO₃(20%, v/v) was added and the volume was made to 20 ml with distilled water. Finally, the mixture was allowed to stand at room temperature in obscurity for 30 min and the absorbance of the solution at 750 nm was measured with spectrophotometer. The total polyphenolic concentration was calculated from a calibration curve using gallic acid as a standard (50–500 mg/l). Data are expressed as milligram of gallic acid equivalents per litre (mg GAE/l).

ABTS assay

Total antioxidant activity of the samples was determined by using ABTS radical cation decolorization assay (Re et al., 1999). ABTS was dissolved in water to a 7-mM concentration and ABTS radical cation (ABTS^•+) was produced by reacting ABTS stock solution with 2.45 mM potassium persulphate (final concentration). The mixture was allowed to stand in the dark at room temperature for 12–16 h before use. Afterwards, the ABTS^•+solution was diluted with ethanol to an absorbance of 0.7 ± 0.02 at 734 nm and equilibrated at 30°C. After addition of 1.0 ml of diluted ABTS⁺solution to 10 μl of samples, the absorbance reading was taken at 30°C for 1 min after initial mixing and up to 6 min. Following the absorbance readings, per cent inhibition of oxidation was calculated for each sample.

Quenching of DPPH radical assay

The 0.1 mmol/l solution of DPPH radical in methanol was prepared and 2 ml of this solution was added to 2 ml of water solution containing 100 μl of wine samples. After 30 min of preparation, absorbance was measured at 517 nm. The lower absorbance of the reaction mixture indicates the higher free radical-scavenging activity. Different concentrations were tested using gallic acid (10–60 mg/l) as a standard for calibration and expressed as mg GAE/l (Villano, Fernandez-Pachon, Troncoso, & Garcia-Parrilla, 2006).

Ferric reducing antioxidant power (FRAP)

The working FRAP reagent was prepared by mixing 10 volumes of 1.0 mol/l acetate buffer, pH 3.6 with 1 volume of 10 mmol/l TPTZ in 40 mmol/l HCl and with 1 volume of 20 mmol/l FeCl₃. In a reaction tube, 100 μl of sample solution and 300 μl of deionized water were added into 3 ml of FRAP reagent. Absorbance was measured after 8 min. A standard curve was prepared using different concentrations of FeSO₄7H₂O (100–1000 μmol/l). The antioxidant efficiency of the sample solution was calculated with reference to the standard curve given by a Fe²⁺solution of known concentration. Ferric reducing power of the sample was expressed in μmol Fe²⁺/ml (Katalinic, Milos, Modun, Music, & Boban, 2004).

Extraction of wine phenols and liquid crystal–mass spectrometer (LC–MS) analysis

Extraction of wine polyphenols were carried out according to the method reported by Garcia-Viguera and Bridle (1995) with the following modifications: deionized water (100 ml) was added to Alphonsowine (100 ml) and the mixture was extracted with ethyl acetate (80 ml). The ester phase was concentrated on a rotary evaporator under 30°C and the residue dissolved in 1:1 (v/v) methanol/water (5.0 ml). Polyphenol analysis by liquid chromatography/electrospray ionization mass spectrometry (LC–ESI-MS) was carried out using an Agilent 1100 series LC and LC/MSD Trap VL Mass Spectrometer (Agilent Technologies, Palo Alto, CA, USA). The high performance liquid chromatography (HPLC) separation was performed on a reversed-phase Zorbax SB-C18 column (250 × 4.6 mm i.d. 5 μm particle size, Agilent Technologies, USA) at 25°C. The mobile phase consisted of 1% acetic acid in water (solvent A) and 1% acetic acid in methanol (solvent B) by applying the following gradient: 0–25 min: 10–22% B, 25–45 min: 22–50% B, 45–55 min: 50–95% B, 55–60 min: 95% B isocratic, 60–63 min: 95–10% B and 63–66 min: 10% B isocratic. The flow rate was 1.0 ml/min. Injection volume was 10 μl with the ultraviolet (UV) detector set to an absorbance wavelength of 280 nm. The ESI parameters were as follows (optimized depending on compounds): nebulizer, 30 psi; dry gas (N₂) flow, 10 l/min and dry gas temperature, 325°C; the ion trap mass spectrometer was operated in a negative ion mode with a scanning range from m/z200 to m/z800. In addition, the activation energy for the mass spectrometry/mass spectrometry (MS/MS) experiment was set to 1.0 V (Sun, Liang, Bin, Li, & Duan, 2007). The identification of the phenolic compounds was confirmed by comparing their mass spectra using NIST 08 Mass Spectral Library (National Institute of Standards and Technology, Gaithersburg, MD, USA).

Sensory evaluation

Sensory attributes (such as taste, aroma, flavour, colour, appearance and aftertaste) were evaluated using a nine-point Hedonic scale (where 1 = dislike extremely and 9 = like extremely) by 10 trained panellists (age group: 20–35) selected from students, staff and faculty of the department who are familiar with wine consumption (Mohanty, Ray, Swain, & Ray, 2006). The mango wines along with selected commercial brand of grape wines were presented to the panel for comparison. The sensory evaluation data were presented as means of the panellist score. A standard t-testwas used to test the statistical significance of the differences observed between the scores of the two drinks (Cass, 1980).

Instrumental evaluation

Three instrumental evaluations were conducted. Separate samples were prepared for instrument evaluation. Total soluble solids (°Brix) were determined by using a hand refractometer (Erma, Tokyo, Japan). The pH value of the sample was determined by using a digital pH meter (Elico, Hyderabad, India). A colorimeter (Chroma Meter CR−400, Konica, NJ, USA) were used to determine the Hunter L* (brightness), a* (red–green component) and b* (yellow–blue component) value of the samples.

Statistical analysis

The correlation between panellist and instrumental evaluation was performed using SPSS software version 14.0 (SPSS Inc., Chicago, IL, USA; Caldeira, Belchior, Climaco, & Bruno de Sousa, 2002). The criterion for statistical significance was p ≤ 0.05 and the values presented were average of the three experiments.

Results and discussion

Physico-chemical characteristics of wine

The mango wine was produced from eight different mango varieties under optimized fermentation conditions by using S. bayanus. The physico-chemical characteristics of wine produced from mango musts are shown in Table 1. The ethanol produced in the mango wines was between 7.8% and 10.3%, comparable with moderate grape wines. The acidity of the mango wine samples ranged between 4.9 and 8.7 g/l (as tartaric acid) and the volatile acidity was between 0.29 and 0.58 g/l (as acetic acid). The pH of the wine produced was more than their respective musts. The content of total fusels in mango wine was between 116 and 363 mg/l, depending on the variety of mango. The total fusels in grape wine ranged between 50 and 100 mg/l (Kourkoutas et al., 2003). Esters, one of the important groups of aroma compounds in wine, are fatty acid and acetate derivatives formed enzymatically during fermentation and contribute to floral and fruity sensory properties of the wine (Nordstrom, 1964). In the present study, the concentrations of esters were in the range of 15–44 mg/l. It was found that ester formation was greatly influenced by pH and temperature. Ester concentration and relative distribution is governed by the yeast strain and fermentation conditions like temperature, pH, fatty acid or sterol levels and oxygen levels (Soleas et al., 1997). The results obtained in this study slightly varied with the results reported by Reddy and Reddy (2009). These differences may be due to mango varietal difference and fermentation conditions.

Table 1. Physico-chemical characteristics of wine produced from different varieties of mango fruits.
Tabla 1. Características fisicoquímicas de vino elaborado con diferentes variedades de mango.

Mango variety	Ethanol (%; v/v)	Total acidity (g/l)	Volatile acidity (g/l)	pH	Residual sugars (g/l)	Higher alcohols (mg/l)	Total esters (mg/l)
Alphonso	10.3	6.5	0.29	3.8	4.1	318	28
Raspuri	8.5	5.3	0.48	3.8	4.4	234	37
Banginapalli	10.0	5	0.30	3.7	4.0	363	44
Totapuri	9.8	6.2	0.40	4.0	4.0	330	25
Sindhoora	8.0	8.7	0.42	4.0	4.0	220	31
Neelam	7.8	7.4	0.58	3.6	4.5	116	18
Rumani	8.9	6.1	0.36	4.0	4.1	229	15
Himami pasand	8.5	4.9	0.53	4.2	4.2	263	22

Total phenol content

Wine represents a rich source of polyphenols like anthocyanins, catechins, proanthocyanidins, flavonols, stilbenes and other phenolics, all potent antioxidants possessing biological properties that may protect against cardiovascular disease (Dell, Buscialia, & Bosisio, 2004). The amounts of phenolic materials vary considerably in different types of wines, depending on the grape variety, environmental factors in the vineyard and the wine processing techniques (Villano et al., 2006). Our results confirm a variation in phenolic content among mango wine samples tested. These results are in agreement with those available in the literature (Campodonico, Barbieri, Pizarro, Sotomayor, & Lissi, 1998). Rocha Ribeiro, Queiroz, Lopes Ribeiro De Queiroz, Campos, and Pinheiro Santana (2007) reported that phenolic compounds content ranged between 48.40 and 208.70 mg/100 g in mango pulp of Brazilian mango varieties. In Alphonso, the total phenol content is reported to have 44 mg/g in pulp (Ravindra & Shivashankar, 2004). During production of fruit wines, the pulp treatment method had a considerable effect on the total content of phenols. In our study, all wines from different varieties of mango have phenolic concentrations higher than 200 mg/l. The highest content of phenolics was found in Alphonso(537.3 ± 3.2 mg/l), Sindhoora(490.3 ± 2.3 mg/l) and Banginapalliwines (456.18 ± 1.8 mg/l). The lowest values were found in Rumani(213.46 ± 2.2 mg/l) and Totapuri(202 ± 1.5 mg/l) wines (Figure 1).

Figure 1. Total phenol content in wines produced from different varieties of mango fruits.

Figura 1. Contenido total de fenoles en vinos elaborados con diferentes variedades de mango.

Determination of total antioxidant capacity (TAC)

The TAC of wine samples was determined by the bleaching of preformed ABTS radical cations. The ABTS⁺reagent was very unstable, and it was degraded in all the samples. The percentage of ABTS inhibition in the presence of an antioxidant (ascorbic acid) is shown in Figure 2and the values were varied from 27.57% to 36.70% for the wines. From the ABTS assay, the wines with highest antioxidant capacity were Himami pasandand Alphonso, followed by Banginapalli, Sindhoora, Raspuri, Neelam, Totapuriand Rumani, respectively. For the antioxidant capacity, one of the most frequently used methods is based on the generation of the highly stable chromophoric cation-radical of ABTS⁺, and the ability of the presumed antioxidant either to delay its appearance or to capture it and diminish its absorbance (Rice-Evans, Miller, & Paganga, 1997).

Figure 2. Percentage of ABTS inhibition activity in wines produced from different varieties of mango.

Figura 2. Porcentaje de actividad inhibidora de ABTS en vinos elaborados con diferentes variedades de mango.

DPPH radical-scavenging activity

The measurement of the composition of DPPH^•radical allows one to determine exclusively the intrinsic ability of a substance to donate hydrogen atoms or electrons to this reactive species in a homogeneous system. The method is based on the reduction of methanolic DPPH solution in the presence of hydrogen-donating antioxidant due to the formation of non-radical form DPPH-H (Duan, Zhang, Li, & Wang, 2006) by the reaction. DPPH is one of the compounds that possess a proton free radical and shows maximum absorption at 517 nm. When DPPH encounters proton radical scavengers, its purple colour faded rapidly. This assay determines the scavenging of stable radical species of DPPH by antioxidants. The radical-scavenging activity is ranged between 73.90% and 85.95% gallic acid equivalents and was found high in wines of Himami pasand, followed by Neelamand Banginapalli(Figure 3).

Figure 3. DPPH radical-scavenging activity in wines produced from different varieties of mango.

Figura 3. Actividad de barrido del radical DPPH en vinos elaborados con diferentes variedades de mango.

Ferric reducing antioxidant power

The Banginapallimango wine exhibited the highest antioxidant potential among all the wines from different mango fruits based on the FRAP assay. The reducing power obtained was in the range of 0.71–2.90 mM ascorbic acid equivalents in all the wines. Alphonsoand Rumanimango wines also exhibited the highest antioxidant potential followed by Neelam, Sindhoora, Himami pasand, Raspuriand Totapuri(Figure 4). FRAP assay measures the reducing potential of an antioxidant reacting with a ferric tripyridyltriazine (Fe³⁺-TPTZ). Generally, the reducing properties are associated with the presence of compounds, which exert their action by breaking free radical chain through donating a hydrogen atom (Duh, Du, & Yen, 1999). Rice-Evans et al. (1997) reported that phenolic compounds have redox properties, which allow then to act as reducing agents, hydrogen donators and singlet oxygen quenchers.

Figure 4. FRAP in wines produced from different varieties of mango.

Figura 4. Poder antioxidante reductor férrico en vinos elaborados con diferentes variedades de mango.

The observations recorded in this investigation revealed that the antioxidant capacity and phenolic content of all the wines produced from mango fruits were comparable. Moreover, highest total phenolic amount was found in wines from Alphonso, Sindhoora, Banginapalliand Himami pasand. Based on the antioxidant assays, it is this suggested that phenolic compounds present in wines have strong scavenging and ferric reducing power. However, there are several methodological limitations for antioxidant activity that involve the generation of radical species, where the presence of antioxidants determines the disappearance of radicals (Cao, Alessio, & Cutler, 1993).

Determination of phenolic composition in mango wine by LC–MS method

In the present study, wine from Alphonsomango variety which is having high total phenol content was selected to determine the phenolic composition by LC–MS. From the analysis, 19 separated compounds (Figure 5) were observed, and out of them 11 phenolic compounds were identified (Table 2) by searching the libraries (NIST, USA) and literature. In Alphonsomango wine, the phenolic compounds were identified as p-hydroxybenzoic acid, caffeic acid, vanillic acid, ferulic acid, sulphonic acid, syringic acid, protocatechuic acid, leutolin, sinapic acid, quinaldinic acid and phenylphosphoramidic acid. In wine, there are two groups of phenolic acids; hydroxybenzoic acids and hydroxycinnamic acids. Hydroxybenzoic acids, including gallic acid, protocatechuic acid, gentisic acid, p-hydroxybenzoic acid, vanillic acid and syringic acid, are derived from benzoic acid. In mango wine, p-hydroxybenzoic acid was found in higher concentration when compared to other phenolic compounds. Sinapic acid as the main constituent of the hydroxycinnamic acid derivative group, increased with harvest time delay, and the same occurred with sinapic acid, while the converse was the true of caffeic acid and ferulic acid, which were also esterified with tartaric acid as the known compounds caftaric acid and fertaric acid, respectively (Cabrita et al., 2008).

Figure 5. LC–MS chromatogram of mango (Alphonso) wine polyphenols.

Figura 5. Cromatograma LC–MS de polifenoles de vino de mango (Alphonso).

Table 2. LC–MS determination of phenolic compounds in Alphonsomango wine.
Tabla 2. Determinación mediante LC–MS de componentes fenólicos en vino de mango Alphonso.

S. no.	Compound name	Retention time (min)	Molecular weight	[M−H]^−(Frag. MS^2 m/z)	% (w/v)
1	p-Hydroxybenzoic acid	9.93	138	137 (93)	50.2
2	Caffeic acid	14.9	175	173 (135)	3.4
3	Vanillic acid	16.5	169	167 (123)	6.4
4	Ferulic acid	21.1	193	192 (134, 149, 179)	7.9
5	Sulphonic acid	22.1	187	186 (103)	11.2
6	Syringic acid	30.0	197	198 (182, 153)	1.5
7	Protocatechuic acid	32.2	155	153 (109)	0.8
8	Leutolin	34.4	281	280 (217, 241, 175)	3.4
9	Sinapic acid	41.4	223	224 (208, 179, 149)	1.2
10	Quinaldinic acid	46.3	173	171 (165, 156)	0.3
11	Phenylphosphoramidic acid	47.9	325	324 (190)	0.9
12	Unknown	18.26	117	116 (118)	0.3
13	Unknown	19.64	191	189 (147, 133)	2.7
14	Unknown	27.77	263	262	1.6
15	Unknown	37.12	329	327 (250)	0.5
16	Unknown	38.74	244	243	0.08
17	Unknown	43.98	373	372 (284)	5.2
18	Unknown	45.12	343	342	0.36
19	Unknown	51.21	329	328 (297, 268)	1.05

Phenolics, important secondary metabolites in the grape berry, play a critical role in determining the organoleptic characteristics of berries and wines. In particular, they contribute to wine characteristics such as colour, flavour, astringency and bitterness. The phenolic compounds in red wines mainly comprise simple phenolic acids (hydroxybenzoic acid and hydroxycinnamic acid) and complicated polyphenols (flavonols, anthocyanin and tannins) which are mainly derived from grape skins and seeds during the vinification process (Macheix, Fleuriet, & Billot, 1990) or from yeast metabolites and ageing in oak barrels. LC–MS is considered the best analytical technique for studying phenolic compounds in grape and wines (Flamini, 2003). To our knowledge, there is no detailed study regarding the composition of phenolic compounds in wine obtained from mango cultivars. So, this preliminary study may contribute new knowledge of the composition of the mango wines.

It has been demonstrated that wine and other products derived from grapes have high antioxidant capabilities. A large number of polyphenols and flavonoids such as p-coumaric acid, cinnamic acid, caffeic acid, ferulic acid, vanillic acid, catechin, epicatechin, quercetin and proanthocyanidins, besides trihydroxy stilbenes such as resveratrol and polydatin, have been reported from grapes. In addition to these, anthocyanins are also present. Kedage, Tilak, Dixit, Devasagayam, and Mhatre (2007) have evaluated the antioxidant potential of 11 grape varieties from India and nearby Asian countries. The phenolic compounds identified by HPLC were gallic acid, catechin, hydrocaffeic acid, O-coumaric acid and rutin in black grape varieties cv. Sharad seedless and cv. Mango, whereas gallic acid, catechin, hydrocaffeic acid and rutin from the green variety cv. Manikchaman. The phenolic compounds identified in the present study were caffeic acid, vanillic acid, ferulic acid, syringic acid, protocatechuic acid, etc., which were also potent antioxidants. These compounds from the present study were comparable to that of phenolic compounds from grapes and antioxidant capacities. It was seen that different varieties of mango wine possess varying degrees of antioxidant potential in different assays. This was due to the contribution to antioxidant activity by different phenolic compounds present.

Sensory studies and panellist evaluation

In the present investigation, characterizations of sensory properties of mango wine produced from eight different mango fruits were studied. Panellists detected the significant differences among the wines in the characteristics of flavour, taste, texture, appearance, colour, sweetness and overall quality (Table 3). The nine-point hedonic test is a rating scale to measure the degree of likeness of food products and has been used for many years for sensory evaluation in the food industry to determine acceptance of the food product. A hedonic rating test can yield both absolute and relative information about the test samples (The Sensory Evaluation Division of the Institute of Food Technologists, 1981). Reliability and validity of the nine-point hedonic scale in the assessment of several hundred food items have been confirmed (Resurreccion, 1998). Panellists determined that the wine made from Alphonso, Raspuri, Banginapalliand Totapuriwere significantly paler than the other wines from Sindhoora, Neelamand Rumani(p < 0.05). The mouth feel of wines made from Alphonso, Banginapalliand Totapuriwere similar with slightly smooth to smooth consistency. Mouth feel of the wines made from Raspuri, Rumani, Sindhoora, Neelamand Himami pasandtended to be “neither smooth nor grainy”. As for wines made from Alphonsoand Banginapalli, the panellists indicated the mouth feel was “smooth”. In overall quality, the results suggested that the wines made from Raspuri, Rumani, Sindhoora, Neelamand Himami pasandmango varieties were significantly lower in quality than the wines made from fresh Alphonso, Banginapalliand Totapuri(p < 0.05). The results suggested that the wines made from Alphonso, Banginapalliand Totapurireceived almost similar overall quality score (Table 3).

Table 3. Sensory evaluation studies on wines from different mango varieties.
Tabla 3. Estudios de evaluación sensorial de vinos de diferentes variedades de mango.

Wine variety	Flavour	Taste	Texture	Appearance	Mouth feel	Overall acceptability
Alphonso	8.90^a ± 0.14	8.26^bd ± 0.04	8.59^b ± 0.02	8.23^ac ± 0.02	8.85^cd ± 0.03	8.62^cd ± 0.01
Raspuri	7.22^bc ± 0.14	7.68^ac ± 0.03	8.14^ac ± 0.02	7.97^bc ± 0.01	8^ac ± 0.07	7.94^ac ± 0.02
Banginapalli	8.56^ac ± 0.05	8.35^bd ± 0.03	8.45^bd ± 0.03	8.76^cd ± 0.00	8.5^cd ± 0.03	8.3^bd ± 0.03
Totapuri	7.84^ac ± 0.05	7.45^ac ± 0.03	7.98^ac ± 0.14	8.1^ac ± 0.07	7.6^ac ± 0.02	7.4^ac ± 0.14
Sindhoora	6.9^ab ± 0.07	6.4^b ± 0.03	7.2^ab ± 0.02	8.45^bd ± 0.03	7.3^bc ± 0.01	7.2^ad ± 0.07
Neelam	6.5^b ± 0.03	6.65^ab ± 0.15	6.9^b ± 0.07	6.3^a ± 0.07	6.7^b ± 0.04	6.6^b ± 0.07
Rumani	7.1^bc ± 0.07	6.8^bc ± 0.07	7.3^bc ± 0.02	7.5^ab ± 0.03	6.6^a ± 0.07	7.0^ab ± 0.14
Himami pasand	6.1^a ± 0.07	6^a ± 0.14	6.3^a ± 0.03	6.7^b ± 0.07	6.9^ab ± 0.03	6.2^a ± 0.07
Notes: Values are given as mean ± SD. Values not sharing a common superscript letter are significantly different at p < 0.05 (Duncan's Multiple Range Test).

The aroma of a wine is one of the most important determinants of its quality. A wine may contain over 800 volatile compounds including alcohols, esters, organic acids, phenols, thiols, monoterpenes and norisoprenoids. Among the volatiles, compounds derived from yeast metabolism are the esters, alcohols and acetates. The essence of a wine's flavour is formed during alcoholic fermentation. Ethanol and glycerol are the most abundant alcohols, followed by higher alcohols and esters, the combinations of which affect the final aroma of a wine (Vilanova & Sieiro, 2006). The total higher alcohol content varied from 116 to 363 mg/l, the highest levels being observed with Banginapallimango cultivar. When the total higher alcohol concentration of a wine is below 300 mg/l, these compounds contribute towards a desirable complexity. However, when above 400 mg/l, they have a negative influence on quality (Swiegers & Pretorius, 2005). The highest ethanol concentration was found in the wines from Alphonso(10.3%) and Banginapalli(10.0%), and, to a great extent, the fresh fruity aromas of wines derive from the mixture of esters produced by the yeast during fermentation (Vilanova & Sieiro, 2006). Esters are particularly important compounds in the aroma of young wines, and, in the present study, the highest concentration of total esters was found in the wine obtained from Banginapalli(44 mg/l), Raspuri(37 mg/l) and Alphonso(28 mg/l). The most prevalent ester in wine is ethyl acetate. This compound adds complexity to the aroma of wines at low levels, but it can give an unpleasant odour (vinegary) to the wine at concentrations higher than 150 mg/l (Mallouchos, Komaitis, Koutinas, & Kanellaki, 2002).

Correlation analysis revealed that there was a slightly positive correlation between taste and flavour (r = 0.17, p < 0.01), taste and mouth feel (r = 0.20, p < 0.01) and taste and overall quality (r = 0.11, p < 0.01). These results indicated that when the score of taste increased, the scores of flavour intensity, mouth feel and overall quality also increased. In addition, correlation analysis results also suggested that overall quality was positively correlated with melon flavour (r = 0.54, p < 0.01) and mouth feel (r = 0.32, p < 0.01). If the scores of melon flavour and mouth feel increased, the score of overall quality increased as well.

Instrumental evaluation

The instrumental evaluation was carried out to determine the significant difference among the pH value, total soluble solids and L*, a* and b* values in wines from different mango fruits, and the results were illustrated in Table 4. The Sindhoorawine had the lowest pH value of the eight wines and is significantly different from the other wines (p < 0.05). Based on the results of the total soluble solids (°Brix), the Alphonsomango had less total soluble solids than the others (p < 0.05). As for the colorimeter evaluation, in the L*, a* and b* values, the results suggested that Alphonso, Banginapalli, Raspuri, Himami pasandand Totapuriwines were significantly lighter than the other wines from Sindhoora, Neelamand Rumaniwithout thickening agents (p < 0.05). The L*, a* and b* values of the Alphonsoand Banginapallimango wines were almost similar.

Table 4. Instrumental evaluation of wines from different varieties of mango fruits.
Tabla 4. Evaluación instrumental de vinos de diferentes variedades de mango.

Wine variety	TSS	pH	L*	a*	b*
Alphonso	2.1^a ± 0.05	3.9^a ± 0.02	41.5^a ± 2.57	2.8^a ± 0.54	13.2^b ± 1.54
Raspuri	2.9^b ± 0.25	3.9^a ± 0.05	46.5^a ± 1.45	1.9^ab ± 0.94	11.8^b ± 1.03
Banginapalli	2.2^a ± 0.07	3.8^a ± 0.04	42.7^a ± 2.25	2.1^a ± 0.64	10.5^b ± 1.50
Totapuri	2.6^a ± 0.05	4.1^a ± 0.07	43.2^a ± 3.11	1.7^ab ± 0.65	10.3^ab ± 1.52
Sindhoora	4.5^b ± 0.03	4.5^b ± 0.04	44.5^b ± 1.88	2.6^ab ± 0.99	10.2^ab ± 1.25
Neelam	3.8^ab ± 0.03	4.2^b ± 0.02	45.1^b ± 3.66	3.1^b ± 1.41	11.1^ab ± 1.32
Rumani	3.2^a ± 0.25	4.2^b ± 0.05	44.0^b ± 2.11	2.3^ab ± 0.72	10.0^a ± 1.72
Himami pasand	4.2^a ± 0.00	3.8^a ± 0.03	47.2^a ± 2.54	1.9^b ± 0.84	11.6^a ± 1.52
Note: ^a,bMeans within a column with different superscripts are different (p < 0.05). TSS, total soluble solids.

Correlation between panellist and instrumental evaluation

Correlation analysis was employed in order to determine the relationship between the panellists and instrumental evaluation. Results suggested that the L*, a* and b* values negatively correlated with the colour score from the panellists (r =−0.35, p < 0.05; Table 5). A review of the data revealed that as the L* value increased, the colour score from the panellists decreased. No other significant correlation results were found between the instrument results and the panellist results.

Table 5. Correlations of characteristics of mango wines from panellist and instrumental evaluation.
Tabla 5. Correlaciones de características de vinos de mango entre evaluación de panelistas e instrumental.

	Appearance	Taste	Flavour	Texture	Mouth feel	Overall acceptability
Appearance	–	0.040	0.138	− 0.114	−0.86	0.063
Taste		–	0.426**	− 0.85	0.265**	0.389**
Flavour			–	− 0.143	0.168**	0.365**
Texture				–	−0.288**	−0.182**
Mouth feel					–	0.636**
Overall acceptability						–
Note: **Correlation is significant at the 0.05 level.

Conclusion

Majority of the health-promoting phenolics are present in mango wine. From the antioxidant assays, it was showed that mango wines possess a substantial antioxidant capacity. The above results of Alphonso, Banginapalliand Totapuriwines have been considered for their better sensory characteristics. Probably this is the first report on the antioxidant capacity and sensory evaluation study on mango wine. Further studies, in order to identify new compounds with a larger number of samples, are under progress in our laboratory.

Acknowledgements

Research work was financially supported by Council of Scientific and Industrial Research (CSIR), New Delhi, and Mr S. Varakumar acknowledges the award of Senior Research Fellowship by CSIR. Special thanks are due to Dr S.C. Basappa, Former Deputy Director and Scientist, Central Food Technological Research Institute, Mysore, India, for his encouragement and critical comments on the manuscript.