IJFS#1884_bozza Ital. J. Food Sci., vol. 32, 2020 - 755 PAPER PHYTOCHEMICAL CHARACTERISTICS AND ANTIOXIDANT ACTIVITY OF SEVERAL FIG (FICUS CARICA L.) ECOTYPES F. ALJANE*, M.H. NEILY and A. MSADDAK Laboratoire d’Aridoculture et Cultures Oasiennes, Institut des Régions Arides (IRA), 4119 Medenine, Université de Gabès, Tunisia *Corresponding author: fateh_aljane@yahoo.fr ABSTRACT In this study, phenolics and reducing sugar compositions of fig fruits (27 Tunisian ecotypes) were analyzed. In addition, the antioxidant activity was determined by two methods; the ABTS and the DPPH assays. Phytochemical composition of the 27 fig ecotypes was found to be very diverse, as the total polyphenols varied from 51.50 (‘Bouholi’) to 100.23 (‘Nasri’) mg gallic acid equivalent/100 g fresh weight. Total flavonoids also varied from 0.33 (‘Bayoudhi1’) to 17.59 (‘SoltaniAhmar’) mg quercetin equivalent/100 g fresh weight, and total anthocyanins extended from 1.61 (‘Besbessi’) to 11.67 (‘Zidi2’) mg/100 g fresh weight. Additionally, DPPH % inhibition ranged from 11.37 (‘Besbessi’) to 64.73 % (‘Bouharrag’) and ABTS from 38.50 (‘Sawoudi5’) to 676.13 (‘Nemri’). The ecotypes ‘Zergui’ and ‘Nasri’ had the highest contents of glucose (5.68 and 4.83 g/ 100 g FW, respectively) and fructose (5.43 and 4.69 g/ 100 g FW, respectively). The results also showed that fig fruits are a good and valuable source of natural antioxidants that can be used in food and medical sectors. Keywords: anthocyanins, antioxidant activity, ecotypes, Ficus carica, flavonoids, fruits, polyphenols Ital. J. Food Sci., vol. 32, 2020 - 756 1. INTRODUCTION Fig (Ficus carica L.), which belongs to the Moraceae family, is considered to be one of the oldest cultivated fruit species and an important crop worldwide for both fresh and dry consumption (DUENAS et al., 2008; BACHIR BEY and LOUAILECHE, 2015). The world production of figs is about one million tons, and it is mostly concentrated in the Mediterranean area (VEBERIC et al., 2008). Tunisia produces about 29 000 tons, which represents 3 % of total world production (FAOSTAT, 2015). In Tunisia, figs have been grown traditionally for several centuries (ALJANE et al., 2018). Local fig ecotypes are numerous and well adapted to the local agro-ecological conditions (ALJANE and FERCHICHI, 2010). Their denominations relate to the fruit color, the period of fruit maturation or to their geographic origin (ALJANE, 2016). Exchange of plant material was frequent between regions of which synonymy and homonymy may be encountered (CHATTI et al., 2004; MARS, 2003; ALJANE and FERCHICHI, 2010). Since several decades, the cultivated areas decreased due to the extinction of many ecotypes, the intensive urbanization as well as the biotic and abiotic stresses (MARS et al., 1998; MARS, 2003) despite the installation of many new plantations (MARS et al., 2008). Whether fresh or dried, figs constitute an important part of the human diet; they are especially rich in fiber, minerals, proteins, sugars, organic acids and antioxidant compounds (ERCISLI et al., 2012). Fig fruit is an important source of minerals, vitamins and polyphenols (DUENAS et al., 2008; ALJANE and FERCHICHI, 2009; ADILETTA et al., 2019). In addition, SOLOMON et al. (2006) recorded high polyphenols contents, especially flavonoids and anthocyanins, the highest being their antioxidant activity. The contents of total polyphenols, anthocyanins as well as total antioxidant activity and other properties such as skin color are strongly influenced by the ecotype (SOLOMON et al., 2006; VEBERIC et al., 2008; CALISKAN and POLAT, 2011; ERCISLI et al., 2012). Similarly, several reports have highlighted the influence of fruit variety, harvest season and growing technology in the fields of phenolic contents (TREUTTER, 2010; VALLEJO et al., 2012). Moreover, antioxidant activity and phenolic compounds varied considerably depending on the part of the fruit. Indeed, several authors have reported the great contribution of fruit skin (compared to pulp) to these compounds especially in darker varieties (VEBERIC et al., 2008; DUENAS et al., 2008). The aim of the present work was to study the phytochemical characteristics and sugar composition of 27 fig ecotypes grown in Tunisia. 2. MATERIALS AND METHODS 2.1. Fruit fig material Ripe Fig fruits from 27 Tunisian fig ecotypes (different fig-growing traditional geographic regions) were harvested in 2015 from the experimental field for germplasm collection of the Institute of Arid Regions (IRA) of Medenine, Tunisia (Table 1). The experimental orchard of 10 years old, included 3 replicates of 5 x 5 m cultivated understandard cultural practices. Within 2 h after harvest, whole fruits were stored at - 20°C for further analysis. Triplicate of 10 frozen fruits samples from each ecotype were homogenized in a blender and used for phytochemical and nutritional analysis. Ital. J. Food Sci., vol. 32, 2020 - 757 Table 1. Ecotype’s name, types, localities of origin of the studied 27 Tunisian fig fruits. Ecotype’s name Types Localities of Origin (Governorate) Bither1 San Pedro Ghadhabna (Mahdia) Jebali1 Smyrna Islands of Kerkenah (Sfax) Mahdoui Smyrna Islands of Kerkenah (Sfax) Bayoudhi1 Common Beni Kheddache (Médenine) Bayoudhi2 Common Toujen (Gabès) Besbessi San Pedro MasjedAissa (Sousse) Bither2 San Pedro Islands of Kerkenah (Sfax) Jemâaoui Smyrna Beni Kheddache (Médenine) Rogabi Smyrna Beni Kheddache (Médenine) Gaa Zir Smyrna Gafsa (Gafsa) Temri Smyrna Islands of Kerkenah (Sfax) Zergui Smyrna Djébba (Béja) Baghali2 Smyrna Ghadhabna (Mahdia) Baghali3 Smyrna Islands of Kerkenah (Sfax) Chetoui Akhal Common Ghadhabna (Mahdia) Croussi Smyrna Beni Kheddache (Médenine) Kahli2 Smyrna Islands of Kerkenah (Sfax) Nemri Smyrna Djébba (Béja) Soltani Ahmer Smyrna Djébba (Béja) Wedlani Smyrna Beni Kheddache (Médenine) Bouharrag Smyrna Djébba (Béja) Bouholi San Pedro Djébba (Béja) Kahli1 Smyrna Ghadhabna (Mahdia) Nasri Smyrna Toujen (Gabès) Sawoudi3 Smyrna Bir Amir (Tataouine) Sawoudi5 Smyrna Gafsa (Gafsa) Zidi2 Smyrna Djébba (Béja) 2.2. Determination of phenolics composition of fig fruits 2.2.1 Methanolic Extraction A total of 1 g of fruit samples was homogenized in 25 ml of extraction solution and 80% methanol. It was stirred for 2 h in the dark at room temperature. The obtained mixture was centrifuged two sequential times for 15 min at 3500 rpm, and supernatant was filtered and taken for further analysis. 2.2.2 Total Polyphenols (TP) Total polyphenols (TP) contents of fig fruits were determined spectrophotometrically using the Folin-Ciocalteu method as previously described by SLINGARD and SINGLETON (1977) with some modifications. The absorbance of each sample was measured at 760 nm using a spectrophotometer (Shimadzu 1600-UV, Japan). Ital. J. Food Sci., vol. 32, 2020 - 758 Quantifications were calculated using a calibration curve daily prepared with known concentrations of gallic acid standards, and results are expressed as mg gallic acid equivalents (GAE) on fresh weight (FW) basis (mg GAE/100 g FW). 2.2.3 Total anthocyanins (TA) Total anthocyanins (TA) contents were quantified in accordance with the pH differential method using two buffer systems as previously described by CHENG and BREEN (1991). In brief, methanolic extract were diluted with two buffer solutions of pH 1 and 4.5. Anthocyanins were estimated using absorbance measurement at 530 and 657 nm in buffers at pH 1.0 and 4.5, respectively; where Absorbance (A) was measured using this formula: A = [(A530 – A657) pH 1.0 - (A530 – A657) pH 4.5] with a molar extinction coefficient of cyanidin-3-glucosid of 29.600. Total anthocyanin quantities were expressed as mg of cyanidin-3-glucoside equivalents (CGE) per g fresh weight of fig fruit (mg CGE/100 g FW). 2.2.4 Total flavonoïds (TF) Total flavonoïds were determined using a colorimetric method previously described by KARADENIZ et al. (2005). Methanolic extract (1 ml) was added to 5 ml of distilled water and mixed. Then, 5% sodium nitrite solution (0.3 ml) was added, followed by 10% aluminium chloride solution (0.3 ml), mixed and incubated at room temperature for 5 min. After incubation, 2 ml of 1M sodium hydroxide were added to the mixture and thenthe volume of reaction mixture was made up to 10 ml with distilled water. The mixture was thoroughly vortexed and the absorbance was determined at 510 nm. Flavonoid contents were calculated using a standard calibration curve, prepared from quercetinand expressed as quercetin equivalent in mg per g fresh weight of fruit (mg quercetin/100 g FW). 2.3. Determination of antioxidant properties of fig fruits The DPPH (1,1 diphenyl 2 pycrilhydrazil (DPPH) radical-scavenging activity of the extract was measured as described by REBAI et al. (2012) and BACHIR BEY et al. (2013). An aliquot (200 µl) of the extract was added to 1 ml of a methanolic DPPH solution (500 µM). The decolorizing process was measured at 517 nm after 30 min of reaction. The scavenging activity percentage of DPPH (%) of the fig extract was calculated using this formula: A = (A blank – A sample)/ (A blank) * 100. For the standard TEAC (Trolox equivalent antioxidant capacity) assay, ABTS (2, 2-azino- bis-3-ethylbenzothiazoline-6-sulfonic acid) was dissolved in methanolic solution (14 mM) and prepared with 10 ml ammonium persulfate (NH2 2S2O8) (4.9 mM) as described by OZGEN et al. (2009). The mixture was diluted in methanol to an absorbance of 1.00±0.01 at 734 nm for long stability (OZGEN et al., 2009). For the spectrophotometric assay, 30 µl of fig fruit extract and 2.97 ml of ABTS+ solution were mixed and incubated for 1 h in darkness. The absorbance was determined at 734 nm using a spectrophotometer (SPECORD 210 Plus-Analytik Jena, Japan). The TEAC was expressed as mg equivalent vitamin C (Acid ascorbic) per 100 g fresh weight of fig fruit (mg EVC/100 g FW). Ital. J. Food Sci., vol. 32, 2020 - 759 2.4. Determination of reducing sugars of fig fruits Reducing sugars (glucose and fructose) were determined according to the method described by MELGAREJO et al. (2003) and GUNDOGDU et al. (2011). Briefly, 10 g fruit was centrifuged at 12000 rpm for 2 min at 4°C, thereafter, the supernatant was filtered and transferred into a vial and used for analysis. Analysis of glucose and fructose was performed by HPLC (KNAUER type) with Eurospher 100 NH2 column and refractive index detector (RI Detectors K-2301) using 80% acetonitrile as a mobile phase. The calculation of concentrations was based on standards solutions of glucose (2%) and fructose (2%). The results were expressed in g/100 g FW and all the samples were analysed in triplicate. 2.5. Statistical analysis All analyses were performed with R software (R Core Team, 2019). DPPH inhibition %data were arcsine transformed to meet assumptions of analysis of variance (ANOVA) for homogeneity of variance and normality and are reported in tables as untransformed values. Data were analyzed using one-way analysis of variance (ANOVA) considering them as factor ecotypes or ecotype groups, followed by post-hoc Tukey multiple comparison to determine if differences (P < 0.05) between fig ecotypes were significant. Additionally, Pearson’s correlation coefficients were also performed based on phytochemical compositions and antioxidant activity of the 27 fig ecotypes. 3. RESULTS AND DISCUSSION 3.1. Fruit skin color The 27 Tunisian local fig ecotypes revealed great morphological variability in their external fruit color (Fig. 1) and consequently were classified into 6 groups which are: (green yellowish, green, red greenish, brown purplish, purple greenish and purple blackish). Among the studied fruit fig ecotypes, fifteen had variably intense purple skin (eight had purple-greenish and seven purple blackish). Additionally, seven ecotypes showed skin color ranging from green to yellow. The remaining ecotypes: ‘Jemâaoui’ and ‘Rogabi’ presented red greenish and ‘Gaa Zir’, ‘Temri’ and ‘Zergui’ were brown purplish (Table 2). Color is one of the most important indicators of maturity and quality of fruits, which is influenced by the concentration and distribution of various anthocyanins (GAO and MAZZA, 1995). 3.2. Fruit phenolic compound contents The level of phenolic compounds of the 27 Tunisian fig ecotypes are given in Table 2, while the mean values obtained for each skin color group are shown in Fig. 2. The one- way ANOVA analysis followed by post-hoc Tukey multiple comparison test of total polyphenols, total anthocyanins and total flavonoids showed highly significant differences (p < 0.001) among the 27 fig ecotypes. When we applied ANOVA analysis to the six skin color groups, the total anthocyanins showed highly significant differences (p<0.001), Ital. J. Food Sci., vol. 32, 2020 - 760 whereas the total flavonoids were only significant (p<0.05). Unlike these compounds, the total polyphenols revealed no significant differences among the six groups. Figure 1. Morphological variability in external fruit color of the 27 studied fig ecotypes (A: Green yellowish, B: Green, C: Red greenish, D: Brown purplish, E: Purple greenish and F: Purple blackish). Ital. J. Food Sci., vol. 32, 2020 - 761 3.2.1 Total polyphenols The total polyphenols (TP) have been reported to be the main phytochemical responsible for the antioxidant activity of figs. The TP contents of fig ecotypes varied from 51.50 (‘Bouholi’) to 100.22 (‘Nasri’) mg GAE/ 100 g FW. The highest TP levels were observed, in descending order, in the following ecotypes (‘Nasri’, ‘Bayoudhi2’, ‘Zidi2’, Baghali3’, ‘Rogabi’, Sawoudi5’) (Table 2). The results of the total polyphenols contents are higher than those obtained in previous studies conducted by ALJANE and SDIRI (2014). Nevertheless, thesecontents are inferior to those found by VALLEJO et al. (2012) and CAPANOGLU (2014), who reported concentrations of 331.93 and 169.4 mg GAE/ 100 g FW in Indian and Turkish figs, respectively, but are comparable to the results of PIGA et al. (2008). On the contrary SOLOMON et al. (2006), CALISKAN and POLAT (2011) and DEBIB et al. (2014) showed that the dark fig fruits contain higher total polyphenols than the light ones. We did not obtain significant differences in total polyphenols based on fruit skin color groups (Fig. 2). This discrepancy might be explained by the fact that total polyphenols contents are greatly influenced by various parameters such as weather conditions, ripening stage, degree of fruit maturation, and postharvest storage conditions (VALLEJO et al., 2012; BACHIR BEY and LOUAILECHE, 2015). 3.2.2. Total anthocyanins The total anthocyanins (TA) are natural pigments belonging to the flavonoid family and are responsible for the red, blue and purple color of many fruits. The total anthocyanins amounts of the studied fig ecotypes varied from 2.57 (‘Baghali3’) to 11.67 (‘Zidi2’) mg CGE/100 g FW (Table 2). ‘Zidi2’ ecotypes had the highest contents (11.67) followed by ‘Sawoudi3’ (9.7) and then ‘Bouholi’ (8.17). It is apparent that purple blackish ecotypes contain more anthocyanins, with average value of 7.11 mg CGE/ 100 g FW. The other fruit ecotypes varied within 3.17 in green-yellowish fruit skin color group to 5.08 mg CGE/100 g FW in red greenish (Fig. 2). These levels are similar to those obtained in our previous study on Tunisian fig varieties, where we found TA to be between 0.55 and 9.16 mg CGE/100 g FW (ALJANE and SDIRI, 2014). SOLOMON et al. (2006) reported that the dark fig ‘Mission’ variety has eight times higher total anthocyanins (10.9 mg CGE/100 g FW) than the red-brown Turkey one (1.3 mg CGE/ 100 g FW), while these compounds were not detected in ‘Brunswick’ and ‘Kadota’ ecotypes, which have light fruit skin color. The TA content of the majority purple-blackish ecotypes is higher than that found by OUCHEMOUKH et al. (2012) in black figs (5.9 mg CGE/ 100 g FW). In addition, the total anthocyanins content of our samples was lower than that of other studies on commercial fig ecotypes (DEL CARO and PIGA, 2007; PIGA et al., 2008; DUENAS et al., 2008; ERCISLI et al., 2012). The results showed that total anthocyanins (TA) contents were strongly influenced by fruit skin color. Indeed, the purple blackish fig ecotypes (‘Zidi2’, ‘Sawoudi3’ and ‘Bouholi’) had the highest contents and might be used as good sources of anthocyanins. Such result is in good agreement with those advanced by SOLOMON et al. (2006), who reported a large contribution of fig fruit skin to the total anthocyanins accumulation. Ital. J. Food Sci., vol. 32, 2020 - 762 Table 2. Total Polyphenols, total anthocyanins and total flavonoids of 27 Tunisian fig ecotypes. Ecotype’s name Total polyphenols mg GAE/ 100 g FW Total anthocyanins mg CGE/ 100 g FW Total flavonoids mg QE/ 100 g FW Fruit skin color group Bither1 60.50±0.74 ef 3.75±0.19 ade 5.68±0.30 ef Green yellowish Jebali1 76.47±0.10 lm 3.43±0.40 ad 11.50±0.90 i Mahdoui 63.21±0.31 g 3.73±0.12 ade 15.26±0.9 j Bayoudhi1 76.62±0.05 lm 3.00±0.1 ab 0.33±0.11a Green Bayoudhi2 88.45±0.47 p 5.61±0.10 ghi 5.68±0.30 ef Besbessi 56.29±0.76 bc 3.33±0.27 ac 12.16±0.30 i Bither2 65.53±1.45 h 6.80±0.82 ij 8.59±0.3 h Jemâaoui 76.15±0.24 lm 6.20±0.1 hj 2.77±0.68 bc Red greenish Rogabi 79.03±0.15 no 3.96±0.24 bcdf 3.76±0.19 cd Gaa Zir 71.75±0.07 ij 4.54±0.38 cdfg 5.42±0.11 def Brown purplish Temri 60.61±0.03 ef 3.67±0.47 ade 5.68±0.3 ef Zergui 54.60±1.36 b 5.57±0.08 ghi 16.57±0.14 jk Baghali2 69.93±0.10 i 3.75±0.08 ade 6.14±0.9 fg Purple greenish Baghali3 79.42±0.61 no 2.57±0.04 a 4.36±0.36 ce Chetoui Akhal 73.35±0.59 jk 7.03±0.72 jk 12.29±0.19 i Croussi 74.57±0.52 kl 4.28±0.24 cdf 5.68±0.41 ef Kahli2 62.33±0.09 fg 4.21±0.08 bcdf de 12.75±0.30 i Nemri 59.34±0.56 de 3.78±0.34 ade 5.76±0.82 eg Soltani Ahmer 61.59±0.66 eg 4.67±0.12 dfg 17.59±0.14 k Wedlani 63.56±0.3 gh 3.55±0.10 c 1.78±0.19 ab Bouharrag 58.20±1.58 cd 5.12±0.24 fh 7.47±0.24 gh Purple blackish Bouholi 51.50±1.49 a 8.17±0.90 i 1.78±0.90 ab Kahli1 61.29±0.62 eg 6.21±0.06 hj 11.70±0.07i Nasri 100.22±0.38 q 3.95±0.94 bcdf 1.85±0.94 ab Sawoudi3 75.44±0.41 km 9.70±0.47 l 8.99±0.48 h Sawoudi5 77.37±0.44 mn 4.90±0.25 efg 11.70±0.26 i Zidi2 81.25±0.99 o 11.67±0.15 m 5.62±0.16 ef Total mean 69.58±11.14 4.08±2.11 7.73±4.72 F value 731.6 85.1 222.1 P value *** *** *** '***' 0.001 '.Values in the same column with different lower- case letters are significantly different at P<0.05 according to post-hoc Tukey multiple comparison, GAE: Gallic acid equivalent, CGE: cyanidin-3-glucoside equivalent, QE: quercetin equivalent, FW: Fresh weight. 3.2.3 Total flavonoids The purple-greenish ecotype ‘Soltani Ahmar’ had the highest contents (17.59 mg QE/100 g FW) followed by ‘Zergui’ from the brown purplish group (16.57 mg QE/100 g FW) and ‘Mahdoui’ from the green-yellowish with an amount of 15.26 mg QE/100 g FW. Whereas, the lowest contents were observed in the following ecotypes (‘Bayoudhi1’, ‘Bouholi’, ‘Wedlani’, ‘Nasri’, ‘Jemâaoui’ and ‘Rogabi’) (Table 2). Ital. J. Food Sci., vol. 32, 2020 - 763 Gy: Green yellowish, G: Green, Rg: Red greenish, Bp: Brown purplish, Pg: Purple greenish, Pb: Purple blackish Figure 2. Total phenolic content (A): total polyphenols, total anthocyanins, total flavonoids, antioxidant capacity (B): DPPH: 1.1 Diphenyl 2 pycril hydrazil, ABTS: acid 2.2-azino-bis-3 ethylbenzothiazoline-6- sulfonique and sugar compositions (C): Glucose and Fructose of 6 fig fruit skin color groups. Different letters indicate significant differences by post-hoc Tukey multiple comparison at p< 0.05. Ital. J. Food Sci., vol. 32, 2020 - 764 The obtained values of total flavonoids are lower than those found by BACHIR BEY and LOUAILECHE (2015) who have advanced contents of 87.24 and 126.55 mg/100 g FW for Algerian light and dark varieties, respectively. The green yellowish group, which is light figs, has the highest total flavonoid contents, followed by green, brown purplish, purple greenish and purple blackish groups (Fig. 2). Such result is quite different from those reported by SOLOMON et al. (2006) and VALLEJO et al. (2012) who found that the total flavonoids contents of dark-purple fig varieties were greater than those of light ones. 3.3. Antioxidant activities The antioxidant activities of the 27 Tunisian fig ecotypes are summarized in Table 3. The one -way ANOVA analysis of ABTS and DDPH followed by post-hoc Tukey multiple comparison test indicated highly significant differences among the 27 fig ecotypes and also between the six groups. 3.3.1 DPPH radical-scavenging activity Data of the scavenging activity against DDPH indicated that the best antiradical effect was achieved by the ‘Bouharrag’ ecotypes (64.73%), whereas, ‘Besbessi’ had the least activity (14.59%) (Table 3). The results clearly revealed a stronger DPPH scavenging activity in purple blackish ecotypes compared to green ones, with average values of 50.25% and 26.95%, respectively (Fig. 2). These results are in accordance with those obtained by BACHIR BEY and LOUAILECHE (2015), who reported a DDPH radical scavenging activity varying from 28.33% to 45.25% in ‘Taghanimt’ and ‘Bouankik’ varieties, respectively. The study of DDPH scavenging activity of Algerian fig varieties clearly showed that dark varieties have stronger DDPH scavenging activities than the light one, with mean values of 41.63 and 31.3%, respectively (BACHIR BEY AND LOUAILECHE, 2015). 3.3.2 ABTS radical cation scavenging activity The results of the scavenging activity of ABTS radical ranged from ‘Mahdoui’ (263.7 EVC mg/100 g FW) to ‘Nemri’ (676.13 EVC mg/100 g FW). It is apparent that antioxidant activity (ABTS) was lower in green yellowish and purple-blackish groups, whereas, the purple greenish showed the highest value (Fig. 2). The current results are comparable to the data obtained by SOLOMON et al. (2006), who indicated that dark fig varieties had high ABTS antioxidant capacities. 3.4. Reducing Sugars compositions The analyses of variance for glucose (GLUC) and fructose (FRUC) revealed significant differences among the 27 studied ecotypes and within the fruit skin color groups. The ecotypes ‘Zergui’ and ‘Nasri’ had the highest contents of glucose (5.68 and 4.83 g/100 g FW, respectively) and fructose (5.43 and 4.69 g/100 g FW) values. Nevertheless, GLUC and FRUC were very low for the ‘Mahdoui’ ecotype (1.12 and 0.86 g/100 g FW, respectively) (Table 3). These results were lower than those obtained by MELGAREJO et al. (2003), as the glucose contents of ‘Tio Antonio’ and ‘Calar’ variety were 15.89 and 13.41 g/100 g FW, respectively. Similarly, CALISKAN and POLAT (2012) reported that GLUC and FRUC contents obtained in ‘Sarilop’ variety were 10.7 and 7.8 mg 100/ g FW, Ital. J. Food Sci., vol. 32, 2020 - 765 respectively. The sugar composition of figs, especially fructose, can influence perceived fruit sweetness (SETSER, 1993). Table 3. Effects of genotype on antioxidant activity (DPPH and ABTS) and sugar compositions for 27 Tunisian fig ecotypes. Ecotype name DPPH inhibition % ABTS mg EVC/ 100 g FW GLUC g/ 100 gFW FRUC g/ 100 gFW Fruit skin color group Bither1 40.74±0.65 l 412.96±6.60 def 1.79±0.29 ab 1.96±0.21 acd Green yellowish Jebali1 28.99±0.99 f 480.26±26.04 hi 3.30±0.90 bde 3.16±0.42 cef Mahdoui 28.63±0.54 f 263.70±9.31 a 1.12±0.88 a 0.86±0.12 a Bayoudhi1 30.38±0.53 g 496.76±5.68 ij 4.66±0.10 ef 3.52±0.09 eg Green Bayoudhi2 26.55±0.50 e 376.40±5.55 cd 2.52±0.30 ad 2.47±0.10 bce Besbessi 14.59±0.52 b 407.96±3.61 de 3.20±0.31 bde 2.89±0.28 bcef Bither2 30.37±0.54 g 601.13±1.02 k 2.30±0.29 ad 2.18±0.81 ae Jemâaoui 38.49±0.50 j 448.60±10.28 fgh 3.37±0.67bde 2.45±0.11bce Red greenish Rogabi 38.49±0.50 j 493.76±6.26 ij 3.21±0.23 bde 2.41±0.26 bce Gaa Zir 45.49±0.50 m 384.06±5.47 cd 3.32±0.11 bde 3.34±0.31 cef Brown purplish Temri 27.42±0.51 e 441.56±7.76 eg 3.32±0.30 bef 2.32±0.45 bce Zergui 46.61±0.53 n 409.36±10.96 de 5.68±0.16 f 5.43±0.10 h Baghali2 29.47±0.50 fg 378.73±1.55 cd 2.00±0.90 abc 1.96±0.10 acd Purple greenish Baghali 3 26.48±0.50 e 658.96±10.15 l 2.57±0.90 ad 2.39±0.08 bce Chetoui Akhal 15.46±0.50 b 465.16±4.19 gi 2.56±0.30 ad 1.98±0.80 ade Croussi 35.54±0.50 i 575.86±3.58 k 2.52±0.40 ad 2.32±0.30 acd Kahli2 45.30±0.60 m 275.60±39.57 a 2.26±0.30 ad 2.15±0.10 ae Nemri 41.05±1.07 l 676.13±13.85 l 4.33±0.12 ef 3.96±0.35 fg Soltani Ahmer 48.07±1.00 o 490.43±10.50 ij 1.73±0.18 ab 1.56±0.11 ab Wedlani 31.52±0.50 h 519.70±1.47 j 3.63±0.20 cde 2.90±0.12 bcef Bouharrag 39.63±0.65 k 347.16±4.07 bc 3.58±1.05 cde 3.29±0.95 deg Purple blackish Bouholi 64.73±0.55 s 264.70±7.59 a 3.19±0.22 bde 3.05±0.95 cef Kahli1 19.62±0.54 d 407.80±5.63 de 2.25±0.90 ad 2.19±0.10 ae Nasri 56.55±0.51 q 465.16±4.19 gi 4.83±0.12 ef 4.69±0.95 ghe Sawoudi3 52.42±0.52 p 462.83±7.00 gi 3.12±0.30 ade 2.52±0.45 bcef Sawoudi5 62.45±0.51 r 383.50±15.05 cd 2.24±0.90 ad 1.82±0.25 ac Zidi2 56.37±0.54 q 322.20±1.92 b 3.84±0.30 de 3.22±0.17 cef Total mean 36.62±13.42 441.13±105.74 3.00±1.15 2.63±1.04 F value 1454 763.1 10.47 13.47 P value *** *** *** *** 0 '***' 0.001. Values in the column with different lower-case letters are significantly different at p< 0.05 according to post-hoc Tukey multiple comparison. DPPH: 1.1 Diphényl 2 PycrilHydrazil. ABTS: acide 2.2- azino-bis-3-ethylbenzothiazoline-6-sulfonique, EVC: equivalent vitamin C, GLUC: Glucose, FRUC: Fructose, FW: Fresh weight. Ital. J. Food Sci., vol. 32, 2020 - 766 It is more likely that the GLUC and FRUC contents depended on fruit skin color (Fig. 2). Similarly, CALISKAN and POLAT (2012) observed that fig genotypes with green or brown fruit skin color had higher GLUC and FRUC than the genotypes with black skin fruit. ABIDI et al. (2011) and CALISKAN and POLAT (2011) have also mentioned that several parameters like: climate variables, cultural practices and harvest time could introduce variability among sugar compositions of fig fruits. 3.5. Correlations between phytochemical and antioxidant activities parameters Obtained results revealed the existence of a significant positive correlation between GLUC and FRUC (r = 0.889). Similar results between fructose and sucrose contents in fig fruits havealso been reported by CALISKAN and POLAT (2011; 2012). In addition, we detected slightly positive correlations between GLUC and DPPH (r = 0.374) and between TA and DDPH antioxidant activity (r = 0.292). The later correlation was not significant as reported by BACHIR BEY and LOUAILECHE (2015) and SOLOMON et al. (2006), who recorded a high correlation (r=0.91).It is also worthy to mention a slightly negative correlation between TP and TF, with value of r=-0.370 (Table 4). Table 4. Pearson’s linear correlation coefficients between total polyphenols (TP), total anthocyanins (TA), total flavonoids (TF), antioxidant capacity (DPPH and ABTS) and sugar composition (GLUC and FRUC) in fig fruits (n =30). TF -0.370 TA 0.053 0.037 DPPH 0.144 -0.038 0.292 ABTS 0.187 -0.225 -0.294 -0.213 GLUC 0.185 -0.171 0.012 0.374 0.104 FRUC 0.082 -0.236 -0.118 0.284 0.154 0.889* Parameters TP TF TA DPPH ABTS GLUC DPPH: 1.1 Diphényl 2 PycrilHydrazil, ABTS: acide 2.2-azino-bis-3-ethylbenzothiazoline-6-sulfonique; *, P<0.05. 4. CONCLUSIONS Since all fig trees were grown under the same environmental and edaphic conditions and subjected to uniform cultural practices (irrigation, fertilization, pruning), the observed differences in the phytochemical composition, antioxidant activity and sugar contents on fig fruits are largely dependent on the biochemical characteristic of each ecotype and to a lesser extent on the ripening stage and postharvest storage conditions. Our results revealed a considerable variation in the phytochemical, antioxidant activity and sugar compositions were observed in the 27 Tunisian fig ecotypes. The ecotypes with purple- blackish skin ‘Bouholi’, ‘Sawoudi3’ and ‘Zidi2’ had the highest contents of TA. Skin color had a highly significant effect on total anthocyanins and was the major tissue that contributed to anthocyanin compositions in figs fruits. Among all studied ecotypes, ‘Nasri’ showed the highest amount of TP. In addition, ‘Bouholi’ ecotype presented the highest antioxidant activity of DDPH and ‘Nemri’, ‘Baghali3’ and ‘Bither2’ ecotypes Ital. J. Food Sci., vol. 32, 2020 - 767 showed the highest ABTS radical scavenging activity. Regarding the sugar contents, the ecotypes with higher values of GLUC and FRUC were ‘Zergui’ and ‘Nasri’, respectively. Due to high contents of bioactive substances and antioxidant activities, figs (particularly dark varieties) are an interesting alternative for antioxidant additives that could be used in pharmaceutical and food industry. 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