Physicochemical characteristics and antioxidant potential of paprika (Capsicum annuum L.) wine

Abstract

Paprika (Capsicum annuum L.) contains various phytochemicals, including carotenoids, ascorbic acid, tocopherol, flavonoids, and phenolic compounds, as well as natural food colorants. Very little information is available regarding wine produced from different colored paprikas. The objectives of this study were to prepare wines from red, orange, and yellow paprika and evaluate their physicochemical characteristics. The alcohol concentration, pH, titratable acidity, and reducing sugar content were not significantly affected by the type of paprika. Hunter's color values varied with the color of paprika. The total mineral content and 2,2-diphenyl-1-picrylhydrazyl radical scavenging potential of red paprika wine were significantly higher; however, the total polyphenol content of yellow paprika wine was significantly higher than that of the other wine samples. This study suggested that paprika could be used to prepare wine and red paprika might be appropriate for producing good-quality wine.

Introduction

Paprika (Capsicum annuum L.) is considered as a healthy food which contains different phytochemicals including carotenoids, ascorbic acid, tocopherol, flavonoids, and phenolic compounds, as well as natural food colorants (AlDuais et al., 2009; Jeong et al., 2006). There are several varieties and colors of paprika. Red paprika shows antitumor-promoting activity (Maoka et al., 2001; Maokaa et al., 2004) and reduction or prevention of cardiovascular diseases. Paprika is effective in the improvement of high density lipoprotein cholesterol and hepatic gene regulation (Aizawa and Inakuma, 2009) especially due to carotenoids. Capsanthin and capsorubin, which are found in red paprika, reveal antioxidative and antitumor activities (Kim et al., 2009). Paprika is a good source of natural colorants and vitamins like C and E, which are found effective on reducing the risk of cancer and cardiovascular disease (Gerster, 1991).

Capsaicinoids, especially capsaicin and dihydrocapsaicin which are the chief alkaloids for paprika’s pungency (Giuffrida et al., 2014), are reported to have health benefits like analgesic, anti- inflammatory, and antioxidant activities (Djamgoz and Isbilen, 2006). They have also shown anticarcinogenic properties by inhibiting androgen-dependent growth of breast cancer, as well as colon, prostate, and gastric adenocarcinoma (Djamgoz and Isbilen, 2006). Carotenoids found in red paprika are reported to have a beneficial effect on human health such as cancer chemopreventive activity (Maoka et al., 2001). Paprika is also rich in phenolic compounds and flavonoids, which are well known for their significant antioxidant and anticancer activities (Lu et al., 2006; Tonin et al., 2005). Thus, the amalgamation of various phytochemicals contributing for the color, taste, and pungency of paprika is the reason for its global popularity.

Fruits and vegetables are highly perishable which are prone to rapid deterioration and are usually wasted if the surplus production is not properly stored or processed. Thus, it is important to develop new methodologies for processing them to minimize the production losses and to make more profits to the farmers. Winemaking is a potential technology from commercial point of view (Moreno-Arribas and Polo, 2005). Several fruits such as kiwi (Soufleros et al., 2001), banana (Akubor et al., 2003), mango (Reddy and Reddy, 2005), cocoa (Dias et al., 2007), orange (Selli et al., 2008), gabiroba (Duarte et al., 2009), and pineapple (Pino and Queris, 2010) have been used to brew wine. Several studies on physicochemical and functional properties of paprika have been carried out. However, very little information is available regarding the production of wine from different colored paprika. Considering the nutritional values of paprika and possibility of brewing wine from it, this study intended to prepare and investigate the quality of wine produced from red, orange, and yellow colored paprika. This study could be useful to promote commercial production and develop high value product from paprika.

Materials and Methods

Chemicals and materials

Folin-Ciocalteu phenol reagent and 1,1-diphenyl-2-picrylhydrazyl (DPPH) were purchased from Sigma-Aldrich (St. Louis, MO, USA). All the chemical and reagents were of analytical grade. Red, orange, and yellow paprikas (Capsicum annuum L.) were purchased from local market in May of 2019. The paprikas were washed with tap water, kept under room conditions (25) for 2 h for surface drying, crushed with gentle pressure with the help of mortar and pestle, followed by homogenization in a mixer (HMF 3450-S; Hanil Co., seoul, Korea) without fluid addition.

Preparation of paprika wine samples

Each 3.5 kg of the homogenized red, orange, and yellow paprika was separately putinto 27-L stainless steel fermenting vessels. Sulfur dioxide (100 ppm) was mixed in the vessels with subsequent stirring. Total volume of the mixture was made up to 23 L with water after mixing 0.54 g/L pectinase, 108.70 g/L sugar, 0.11 g/L yeast nutrients, 0.65 g/L acid blend, 0.07 g/L tannin, and 0.05 g/L potassium metabisulfite. The mixture was subjected to fermentation at room temperature using a rehydrated inoculum of Fermivin 7013 dry yeast (Saccharomyces cerevisiae) (Gist Brocades, Prouvy, France) at the rate of 2.5 g dry yeast per liter of fermenting material. The wine was racked after fermentation and aged in a glass bottle (23 L). Wine samples were stored at 18°C for 3 months. The finished wines were clarified with 250 mg/L of bentonite and filtered through 1.5 and 0.5 µm of filter papers (Buon vino MGF, Inc, Ontario, Canada) and were stored in 750- mL glass bottles at 4°C until analysis.

Measurement of chemical characteristics

A pH Meter (Model 250, Beckman Coulter, Inc., Fullerton, CA, USA) was used to measure the pH values of wine samples. Titratable acidity (TA) was determined following the method described by Lee et al. (2017). The wine sample (5 mL) was mixed with deionized water (125 mL) and titrated using a 0.1 N sodium hydroxide solution to an endpoint pH 8.2. The alcohol concentration of wine samples was measured following the method described by Ough and Amerine (1988). The reducing sugar content of wine samples was determined following the method described by Nanos and Karayannis (1991).

Color measurement

The L*, a*, and b* values of the wine samples were measured using a Chroma Meter(CR-300, Minolta Corp., Tokyo, Japan). The ‘L*’ value is a measure of lightness, from completely opaque (0) to completely transparent (100). The ‘a*’ value is a measure of redness (‘−a’ greenness), and the ‘b*’ value measures yellowness (‘−b’ blueness). A calibration plate (Minolta Corp.; YCIE=94.5, XCIE=0.3160, YCIE=0.330) and a standard plate (Hunter Associates Laboratory Inc., Reston, VA, USA; L*=97.51, a*= −0.18, b*=+1.67) were used to standardize the instrument with D65 illuminant (Kim et al., 2014).

Determination of mineral content

An aliquot of wine sample (15 mL) and 1% (v/v) nitric acid (0.5 mL) was mixed. The mixture was diluted with distilled water (2 mL) and mixed thoroughly. The mineral composition of wine samples was determined using an inductively coupled plasma- atomic emission spectrophotometer (ICP-AES; Varian Vista Inc., Victoria, Australia) following the manufacturer’s protocol (Skujins, 1998).

DPPH radical scavenging activity

The DPPH radical scavenging activity was measured according to the method described by Cheung et al. (2003). A freshly prepared 0.1 mL of 0.1% (w/v) DPPH-methanol solution was mixed with 0.1 mL of wine sample in a 96-well microplate. The microplate was incubated for 30 min at room temperature in dark condition and then the absorbance value of the mixtures was measured at 517 nm using a spectrophotometer (Multiskan GO, Thermo Scientific, Vantaa, Finland). The radical scavenging activity (RSA) was calculated as a percentage inhibition using the following equation.

%RSA=(1–S^ab/C^ab)×100

where S^ab is the absorbance of the mixture of sample and DPPH solution and C^ab is absorbance of DPPH solution without sample.

Total polyphenol content

The total polyphenol content of wine samples was determined according to the Folin-Ciocalteu method (Singleton et al., 1999). Wine sample (50 µL) and 2% (w/v) aqueous sodium carbonate (1000 µL) were mixed using a vortexer and allowed to react for 3 min at room temperature. After 3 min, 50 µL of 1 N Folin- Ciocalteau reagent was added to the mixture, followed by an incubation for 30 min at room temperature in dark condition. The absorbance values of the reaction mixtures were measured at 750 nm using a microplate spectrophotometer (Multiskan GO, Thermo Scientific). Gallic acid was used as a standard to plot the calibration curve and the total polyphenols were determined as gallic acid equivalents (ìg GAE/mL wine).

Statistical analysis

Data were subjected to analysis of variance using SAS 9.3 (SAS Institute, Inc. Cary, NC, USA). The significant differences among the sample means were separated using Tukey test at 5% probability. The mean values of triplicate experiments were considered for statistical analysis unless otherwise mentioned.

Results and Discussion

Chemical characteristics

The alcohol content, pH, TA, and reducing sugar of wine samples were not significantly different (Table 1). The pH and TA values of paprika wine were within the range, however the alcohol concentration was more than the values found in a wine prepared from rice by mixing blueberry and black rice powders (Kim et al.,

Table 1. Chemical characteristics of paprika wine prepared with different-colored paprikas

Color values

Hunter’s color values of paprika wine samples were significantly different (Table 2). The lightness value of Y-W (64.91) was significantly high followed by O-W (63.54) and R-W (60.22). The redness (1.71) and yellowness (15.50) values of R-W were significantly high among three wine samples.

Table 2. Hunter’s color values of paprika wine prepared with different-colored paprikas

Variations in lightness, redness, and yellowness values among the paprika wine samples might have been due to addition of different proportions of colorants (AlDuais et al., 2009; Jeong et al., 2006), including carotenoids found in the different varieties of paprika (Kim et al., 2016).

Mineral content

The amounts of mineral elements in different paprika wine samples were significantly different (Table 3). K was the most abundant mineral found in all paprika wine. R-W (786.24 mg/kg) showed the highest amount of K followed by O-W (456.66 mg/kg). The lowest amounts of K, Na, Mg, and Mn were found in Y-W, whereas R-W contained the lowest amounts of Ca and Cu. The total mineral contents of R-W (1061.09 mg/kg) was more than double than that of Y-W (482.84 mg/kg).

Table 3. Mineral content (mg/kg) of paprika wine prepared with different-colored paprikas

The variation in mineral contents of different wine samples might be due the genotypic differences of paprika. Different minerals have various physiological functions in human body. Consumption of high Na and low K is associated with potential risk of hypertension and cardiovascular diseases (Luta et al., 2018). Zn plays roles in growth, development, differentiation, DNA synthesis, RNA transcription, and cellular apoptosis (MacDiarmid et al., 2000).

Table 4. DPPH radical scavenging activities and total polyphenolic content of paprika wine prepared with different-colored paprikas

Antioxidant potential

Antioxidant potential of paprika wine was assessed based on the DPPH free radical scavenging activities and total polyphenol contents. The DPPH radical scavenging activities of R-W (81.23%) was significantly high, whereas the total polyphenol content of Y- W was significantly high among the samples. Kim et al. (2011) reported that different colored and varieties of paprika have significantly different antioxidant potential. This might be the reason for the variations in DPPH radical scavenging activities and total polyphenol content of paprika wine samples.

Conclusion

Paprika wine samples were prepared by fermenting red, orange, and yellow paprikas. The general chemical characteristics of the wine samples were not significantly affected by the type of paprika. Hunter’s color values of wine samples were differed with the color of paprika. Total mineral content and DPPH radical scavenging potential of R-W were significantly high, however, total polyphenol content of Y-W was significantly high among the wine samples. Further studies may be necessary for commercial production of paprika wine.

Conflict of interest

The authors declare no conflict of interest.