Carob ( Ceratonia siliqua L.) fruit pulp from 12 wild and 8 domesticated trees from 15 Moroccan localities were investigated for their polyphenols contents: total polyphenols content (53.22 - 118.04 mg and 57.46 - 183.31 mg), total flavonoids (1.41 - 4.83 mg and 1.62 - 7.46 mg) and condensed tannins (1.47 - 7.36 mg and 1.85 - 6.66 mg) in one carob fresh pulp for wild and domesticated trees, respectively. Fruit pulp from trees in the same region shows variable contents in polyphenols, flavonoids and condensed tannins.
Ceratonia siliqua L. (carob tree) is a perennial Fabaceous tree which is flourishing in the Mediterranean area since antiquity [
Carob pod is the fruit of carob tree and is mostly used in the food industry for locust bean gum: polysaccharides (galactomannans) contained in the endosperm of the seeds. Nevertheless, carob pod consists for the most part of pulp (90%), which is rich in sugars [
Due to their chemical composition, carobs are used in industry, in food and in medicine [
As Morocco is the fifth carob producer in the world after Spain, Italy, Portugal and Greece [
Acetone (C3H6O); M = 58.08 g/mol; S.C. Chemical Company S.A., Iasi, Romania. Sodium carbonate Na2CO3; M = 105.99 g/mol; S.C. Chemical Company S.A., Iasi, Romania. Folin-Ciocalteu reagent; 1 L = 1.24 kg; Merck KGa A., Darmstadt, Germany. Gallic acid (OH)3C6H2COOH∙H2O; M = 188.139 g/mol; Union Chimique Belge, S.A., Brussels, Belgium. Hexahydrated Aluminum Chloride AlCl3∙6H2O; M = 241.43 g/mol; Chemical Company, Iasi, Romania. Solid Quercetin ≥ 95% (HPLC); M = 302.24 g/mol; Sigma Aldrich, India. Ammonium iron (II) sulfate 99.7%; (NH4)2Fe(SO4)2∙6H2O; M = 392.158 g/mol; Chimopar S.A., Bucharest, Romania. n-Butan-1-ol CH3(CH2)3OH; 1 L = 0.81 kg; M = 74.12 g/mol; Merck KGah, Darmstadt, Germany. Hydrochloric acid HCl 37%; 1 L = 1.19 kg; M = 36.46 g/mol; Lachner, Neratovice, Czech Republic.
Carob mature fruits have been collected from 12 wild trees and 8 domesticated ones from 15 different localities in Morocco. Collection has been carried out between July and September 2012. Fruits were stored in the dark at room temperature (25˚C ± 2˚C). Origins, localities, numbers, latitudes, longitudes and altitudes may be seen in
Region | Locality | Tree number | Latitude | Longitude | Altitude (m) |
---|---|---|---|---|---|
Wild trees | |||||
Western Rif | Ghorghez (Zaitouna-Tetouan) | 1 | 35˚32'45.48"N | 5˚23'08.62"W | 204 |
Zinat (Bni Hassane-Tetouan) | 2 | 35˚25'13.22"N | 5˚23'23.54"W | 330 | |
Isslan (Bni Hassane-Tetouan) | 3 | 35˚16'57.66"N | 5˚16'33.56"W | 876 | |
Belyounech (Fnidaq) | 4 | 35˚54'15.70"N | 5˚23'23.95"W | 172 | |
Ain Beida 2 (Mokrissat-Ouezzane) | 5 | 34˚58'52.17"N | 5˚29'42.16"W | 178 | |
Ain Kalaa (Mokrissat-Ouezzane) | 6 | 34˚55'55.21"N | 5˚21'16.55"W | 643 | |
Ain Koub (Mokrissat-Ouezzane) | 7 | 34˚57'08.68"N | 5˚21'45.01"W | 642 | |
Zoumi 2 (Mokrissat-Ouezzane) | 8 | 34˚51'23.88"N | 5˚18'35.25"W | 648 | |
Eastern Rif | Midar (Nador) | 9 | 34˚58'20.56"N | 3˚37'38.80"W | 1061 |
Kassita (Nador) | 10 | 34˚53'22.12"N | 3˚46'59.38"W | 860 | |
Western Middle Atlas | Guelmouss (Sidi Hassine-Khenifra) | 11 | 33˚09'05.60"N | 5˚52'37.40"W | 1250 |
Ain Asserdoune (Beni Mellal) | 12 | 32˚19'18.70"N | 6˚19'45.72"W | 834 | |
Domesticated trees | |||||
Western Rif | M’hannech II (Tetouan) | 13 | 35˚33'39.95"N | 5˚21'44.52"W | 60 |
Kitane (Zaitouna-Tetouan) | 14 | 35˚32'15.50"N | 5˚20'20.57"W | 126 | |
Oued Laou | 15 | 35˚26'46.90"N | 5˚05'51.72"W | 58 | |
Ain Beida 1(Mokrissat-Ouezzane) | 16 | 34˚58'56.24"N | 5˚29'39.16"W | 174 | |
Zoumi 1 (Mokrissat-Ouezzane) | 17 | 34˚48'21.34"N | 5˚21'14.94"W | 543 | |
Eastern Middle Atlas | Moulay Idriss Zerhoun 1 | 18 | 34˚03'33.97"N | 5˚31'52.70"W | 482 |
Moulay Idriss Zerhoun 2 | 19 | 34˚03'35.47"N | 5˚32'05.36"W | 470 | |
Moulay Idriss Zerhoun 3 | 20 | 34˚03'27.87"N | 5˚31'55.70"W | 466 |
Fresh carob fruits have been dried during 2 weeks at 70˚C until stabilization of dry weight. Dried fruits have been chopped, deseeded and crushed on a knife mill MICROTRON MB 500 (KINEMATICA) at 15,000 rpm. The resulted powder has been sifted on a stainless steel sieve Fisher Scientific LABOSI to obtain particles of average diameter less than 200 µm. The latter powder was used for extraction.
20 g of powder was macerated in 200 mL distillated water 6 h at 4˚C. Then, this mixture was centrifuged 15 min at 5000 rpm. The fresh residue was extracted with 70% acetone (ratio of extraction 1:5; w/v) with a magnetic stirrer (30 min; 350 rpm), then centrifuged 10 min at 5000 rpm. This extraction was repeated two times. The three supernatants were pooled and incubated at 4˚C until analyses.
The total polyphenols content was determined by the Folin-Ciocalteu colorimetric method [
Flavonoids content was determined by the method described by Djeridane et al. [
Condensed tannins content was determined by Butanol-HCl method [
All measurements were run in triplicates (n = 3), and the values were averaged and given along with standard error (±SE). Analyses were performed with Statistical 6; averages were compared by Duncan test and values beyond p ≤ 0.05 were considered to be significant.
For wild trees, TPCF ranged from 7.00 to 19.36 mg GAE/g, TPCD from 7.80 to 22.75 mg GAE/g and TPCP from 53.22 to 118.04 mg GAE/one fresh pulp. Ghorghez powder showed the higher TPCF and TPCD (19.36 and 22.75 mg GAE/g), followed by Guelmouss (18.61 and 21.21) and Ain Asserdoune (17.25 and 19.41). Kassita powder had the lowest TPCF and TPCD (7.00 and 7.80 mg GAE/g). The richest pulp in polyphenols belonged to the tree of Ain Beida 2 (118.04 mg GAE/one fresh pulp) followed by Zinat (109.36) and Ghorghez (107.83). The poorest pulp in polyphenols was from Guelmouss (53.22 mg GAE/one fresh pulp)
Locality | TPCF (mg GAE/g) | TPCD (mg GAE/g) | TPCP (mg GAE/one fresh pulp) | |
---|---|---|---|---|
Wild trees | ||||
1 | Ghorghez (Zaitouna-Tetouan) | 19.36 ± 0.06a | 22.75 ± 0.07a | 107.83 ± 0.33d |
2 | Zinat (Bni Hassane-Tetouan) | 14.43 ± 0.04f | 16.25 ± 0.05f | 109.36 ± 0.34d |
3 | Isslan (Bni Hassane-Tetouan) | 15.50 ± 0.04e | 18.65 ± 0.04d | 65.28 ± 0.16l |
4 | Belyounech (Fnidaq) | 12.47 ± 0.04h | 14.39 ± 0.05h | 108.64 ± 0.38d |
5 | Ain Beida 2 (Mokrissat-Ouezzane) | 9.29 ± 0.09l | 10.80 ± 0.10k | 118.04 ± 1.13c |
6 | Ain Kalaa (Mokrissat-Ouezzane) | 7.55 ± 0.02p | 8.54 ± 0.02o | 85.64 ± 0.22i |
7 | Ain Koub (Mokrissat-Ouezzane) | 8.58 ± 0.12n | 10.07 ± 0.13l | 54.88 ± 0.74n |
8 | Zoumi 2 (Mokrissat-Ouezzane) | 13.91 ± 0.07g | 15.90 ± 0.07g | 103.04 ± 0.48e |
9 | Midar (Nador) | 8.53 ± 0.18n | 10.02 ± 0.20lm | 66.73 ± 1.36l |
10 | Kassita (Nador) | 7.00 ± 0.04r | 7.80 ± 0.05p | 73.21 ± 0.48j |
11 | Guelmouss (Sidi Hassine-Khenifra) | 18.61 ± 0.05b | 21.21 ± 0.05b | 53.22 ± 0.14o |
12 | Ain Asserdoune (Beni Mellal) | 17.25 ± 0.10c | 19.41 ± 0.11c | 88.49 ± 0.50h |
Domesticated trees | ||||
13 | M’hannech II (Tetouan) | 6.97 ± 0.02r | 8.43 ± 0.02o | 57.46 ± 0.17m |
14 | Kitane (Zaitouna-Tetouan) | 9.05 ± 0.04m | 9.86 ± 0.04m | 88.26 ± 0.37h |
15 | Oued Laou | 10.73 ± 0.04j | 11.99 ± 0.05j | 90.52 ± 0.36g |
16 | Ain Beida 1 (Mokrissat-Ouezzane) | 11.07 ± 0.02i | 12.24 ± 0.02i | 157.16 ± 0.33b |
17 | Zoumi 1 (Mokrissat-Ouezzane) | 16.04 ± 0.04d | 18.06 ± 0.04e | 183.31 ± 0.44a |
18 | Moulay Idriss Zerhoun 1 | 10.48 ± 0.04k | 11.84 ± 0.04j | 74.09 ± 0.27j |
19 | Moulay Idriss Zerhoun 2 | 8.00 ± 0.03o | 9.05 ± 0.03n | 69.92 ± 0.24k |
20 | Moulay Idriss Zerhoun 3 | 8.94 ± 0.04m | 10.19 ± 0.04l | 100.42 ± 0.43f |
TPCF: Total Polyphenols Content in Fresh powder, TPCD: Total Polyphenols Content in Dry powder, TPCP: Total Polyphenols Content in one fresh Pulp. The data represent Mean ± SE of replicates (n = 3). Values in the same rows carrying different letters are significantly different between treatments and control by Duncan’s multiple range tests at p ≤ 0.05.
For domesticated trees, TPCF ranged from 6.97 to 16.04 mg GAE/g, TPCD from 8.43 to 18.06 mg GAE/g and TPCP from 57.46 to 183.31 mg GAE/one fresh pulp. Powder from domesticated tree of Zoumi 1 was the richest in polyphenols (16.04 and 18.06 mg GAE/g for TPCF and TPCD), followed by Ain Beida 1 (11.07 and 12.24) and Oued Laou (10.73 and 11.99). Moulay Idriss Zerhoun 2 powder showed the lowest TPCF and TPCD (8.00 and 9.05 mg GAE/g). The richest pulp in polyphenols belonged to the domesticated tree of Zoumi 1 (183.31 mg GAE/one fresh pulp), followed by Ain Beida 1 (157.16) and Moulay Idriss Zerhoun 3 (100.42). The poorest pulp in polyphenols was from M’hannech II with 57.46 mg GAE/one fresh pulp
For wild trees, TFCF ranged from 0.19 to 0.87 mg QE/g, TFCD from 0.21 to 1.02 mg QE/g and TFCP from 1.41 to 4.83 mg QE/g. Powder from Ghorghez tree showed the highest TFCF and TFCD (0.87 and 1.02 mg QE/g, respectively), followed by powders from Guelmouss tree (0.67 and 0.77), and Zoumi 2 tree (0.49 and 0.55). The lowest TFCF and TFCD were observed in the case of powder from Ain Kalaa tree (0.19 and 0.21 mg QE/g). The richest pulp in flavonoids was from Ghorghez tree with 4.83 mg QE/one fresh pulp, followed by Belyounech (3.96) and Zoumi 2 (3.60) trees. The poorest pulp in flavonoids was from Isslan tree with 1.41 mg QE/one fresh pulp
Locality | TFCF (mg QE/g) | TFCD (mg QE/g) | TFCP (mg QE/one fresh pulp) | |
---|---|---|---|---|
Wild trees | ||||
1 | Ghorghez (Zaitouna-Tetouan) | 0.87 ± 0.001a | 1.02 ± 0.0006a | 4.83 ± 0.003b |
2 | Zinat (Bni Hassane-Tetouan) | 0.36 ± 0.001f | 0.41 ± 0.001g | 2.76 ± 0.008h |
3 | Isslan (Bni Hassane-Tetouan) | 0.34 ± 0.01ghi | 0.40 ± 0.01gh | 1.41 ± 0.04n |
4 | Belyounech (Fnidaq) | 0.46 ± 0.003e | 0.52 ± 0.004e | 3.96 ± 0.03e |
5 | Ain Beida 2 (Mokrissat-Ouezzane) | 0.25 ± 0.003jk | 0.28 ± 0.004j | 3.12 ± 0.04g |
6 | Ain Kalaa (Mokrissat-Ouezzane) | 0.19 ± 0.009m | 0.21 ± 0.01m | 2.11 ± 0.11j |
7 | Ain Koub (Mokrissat-Ouezzane) | 0.26 ± 0.003j | 0.30 ± 0.004j | 1.64 ± 0.02lm |
8 | Zoumi 2 (Mokrissat-Ouezzane) | 0.49 ± 0.005d | 0.55 ± 0.006d | 3.60 ± 0.04f |
9 | Midar (Nador) | 0.20 ± 0.006lm | 0.23 ± 0.006l | 1.56 ± 0.04mn |
10 | Kassita (Nador) | 0.23 ± 0.011k | 0.26 ± 0.01k | 2.45 ± 0.11i |
11 | Guelmouss (Sidi Hassine-Khenifra) | 0.67 ± 0.002b | 0.77 ± 0.002b | 1.93 ± 0.006k |
12 | Ain Asserdoune (Beni Mellal) | 0.35 ± 0.002fg | 0.39 ± 0.002gh | 1.79 ± 0.008kl |
Domesticated trees | ||||
13 | M’hannech II (Tetouan) | 0.48 ± 0.009d | 0.57 ± 0.01d | 3.91 ± 0.08e |
14 | Kitane (Zaitouna-Tetouan) | 0.45 ± 0.001e | 0.48 ± 0.001f | 4,35 ± 0.01d |
15 | Oued Laou | 0.21 ± 0.001l | 0.23 ± 0.001l | 1.76 ± 0.008kl |
16 | Ain Beida 1(Mokrissat-Ouezzane) | 0.33 ± 0.01hi | 0.36 ± 0.01i | 4.65 ± 0.13c |
17 | Zoumi 1 (Mokrissat-Ouezzane) | 0.65 ± 0.01c | 0.73 ± 0.01c | 7.46 ± 0.12a |
18 | Moulay Idriss Zerhoun 1 | 0.34 ± 0.006gh | 0.36 ± 0.004i | 2.41 ± 0.04i |
19 | Moulay Idriss Zerhoun 2 | 0.19 ± 0.003m | 0.21 ± 0.003m | 1.62 ± 0.02lm |
20 | Moulay Idriss Zerhoun 3 | 0.32 ± 0.003i | 0.38 ± 0.01h | 3.59 ± 0.04f |
TFCF: Total Flavonoids Content in Fresh powder, TFCD: Total Flavonoids Content in Dry powder, TFCP: Total Flavonoids Content in one fresh Pulp. The data represent Mean ± SE of replicates (n = 3). Values in the same rows carrying different letters are significantly different between treatments and control by Duncan’s multiple range tests at p ≤ 0.05.
For domesticated trees, TFCF ranged from 0.19 to 0.65 mg QE/g, TFCD from 0.21 to 0.73 mg QE/g and TFCP from 1.62 to 7.46 mg QE/g. Fresh and dry powders from Zoumi 1 tree were the richest in flavonoids (0.65 and 0.73 mg QE/g, respectively), followed by M’hannech II tree (0.48 and 0.57) and Kitane tree (0.45 and 0.48). Fresh and dry powders of Moulay Idriss Zerhoun 2 tree were the poorest in flavonoids with a TFCF and a TFCD of 0.19 and 0.21 mg QE/g. Pulp from Zoumi 1 tree showed the highest TFCP (7.46 mg QE/one fresh pulp), followed by Ain Beida 1(4.65) and Kitane (4.35) trees. The poorest pulp in flavonoids was from Moulay Idriss Zerhoun 2 tree with a TFCP of 1.62 mg QE/one fresh pulp
For wild trees, CTCF ranged from 0.30 to 0.85 mg PE/g, CTCD from 0.35 to 1.02 mg PE/g and CTCP from 1.47 to 7.36 mg PE/one fresh pulp. The highest CTCF and CTCD corresponded to the powder of Isslan tree (0.85 and 1.02 mg PE/g, respectively), followed by the powders from Ghorghez (0.72 and 0.84) and Midar (0.68 and 0.80) trees. The lowest CTCF and CTCD corresponded to the powder of Ain Koub (0.30 and 0.35 mg PE/g). The richest pulp in condensed tannins belonged to Ain Kalaa tree (7.36 mg PE/one fresh pulp), followed by Ain Beida 2 (6.61) and Midar (5.35) trees. The poorest pulp in condensed tannins belonged to Guelmouss tree with 1.47 mg PE/one fresh pulp
For domesticated trees, CTCF ranged from 0.22 to 0.59 mg PE/g, CTCD from 0.24 to 0.68 mg PE/g and CTCP from 1.85 to 6.66 mg PE/one fresh pulp. Powder from Moulay Idriss Zerhoun 3 tree showed the highest CTCF and CTCD (0.59 and 0.68 mg PE/g, respectively), followed by the powders from Zoumi 1 (0.48 and 0.54) and Kitane (0.47 and 0.51) trees. Powder from Oued Laou tree showed the lowest CTCF and CTCD (0.22 and 0.24 mg PE/g). The richest pulp in condensed tannins was from Moulay Idriss Zerhoun 3 tree with 6.66 mg PE/one fresh pulp, followed by Ain Beida 1 (6.37) and Zoumi 1 (5.47) trees. The poorest pulp in condensed tannins was from Oued Laou tree with 1.85 mg PE/one fresh pulp
The present study highlights differences in polyphenols contents among powders and pulps from wild and domesticated trees of Ceratonia siliqua L.
Thereby, carob dry powders from wild trees show total polyphenols, flavonoids and condensed tannins contents reaching 22.75 mg GAE/g, 1.02 mg QE/g and 1.02 mg PE/g, respectively. Also, pulps from wild trees show total polyphenols, total flavonoids and condensed tannins contents by one fresh carob pulp reaching 118.04 mg GAE, 4.83 mg QE and 7.36 mg PE, respectively, while domesticated trees show lower contents for powders. Thus, total polyphenols, flavonoids and condensed tannins contents reach 18.06 mg GAE/g, 0.73 mg QE/g and 0.68 mg PE/g, respectively. For one fresh carob pulp, they reach 183.31 mg GAE, 7.46 mg QE and 6.66 mg PE, respectively. Indeed, Marakis et al. [
Locality | CTCF (mg PE/g) | CTCD (mg PE/g) | CTCP (mg PE/one fresh pulp) | ||
---|---|---|---|---|---|
Wild Trees | |||||
1 | Ghorghez (Zaitouna-Tetouan) | 0.72 ± 0.007b | 0.84 ± 0.01b | 4.00 ± 0.04g | |
2 | Zinat (Bni Hassane-Tetouan) | 0.54 ± 0.003f | 0.61 ± 0.003g | 4.13 ± 0.02g | |
3 | Isslan (Bni Hassane-Tetouan) | 0.85 ± 0.008a | 1.02 ± 0.01a | 3.57 ± 0.03h | |
4 | Belyounech (Fnidaq) | 0.54 ± 0.006f | 0.62 ± 0.01fg | 4.70 ± 0.05f | |
5 | Ain Beida 2 (Mokrissat-Ouezzane) | 0.52 ± 0.001g | 0.60 ± 0.001g | 6.61 ± 0.02b | |
6 | Ain Kalaa (Mokrissat-Ouezzane) | 0,65 ± 0,006d | 0.73 ± 0.01d | 7.36 ± 0.07a | |
7 | Ain Koub (Mokrissat-Ouezzane) | 0.30 ± 0.001k | 0.35 ± 0.001m | 1.90 ± 0.009l | |
8 | Zoumi 2 (Mokrissat-Ouezzane) | 0.56 ± 0.02f | 0.63 ± 0.02f | 4.11 ± 0.11g | |
9 | Midar (Nador) | 0.68 ± 0.004c | 0.80 ± 0.005c | 5.35 ± 0.03d | |
10 | Kassita (Nador) | 0.47 ± 0.002h | 0.52 ± 0.002ij | 4.92 ± 0.02e | |
11 | Guelmouss (Sidi Hassine-Khenifra) | 0.51 ± 0.004g | 0.58 ± 0.005h | 1.47 ± 0.01m | |
12 | Ain Asserdoune (Beni Mellal) | 0.37 ± 0.003j | 0.42 ± 0.003l | 1.91 ± 0.01l | |
Domesticated trees | |||||
13 | M’hannech II (Tetouan) | 0.25 ± 0.003l | 0.31 ± 0.003n | 2.09 ± 0.02k | |
14 | Kitane (Zaitouna-Tetouan) | 0.47 ± 0.007h | 0.51 ± 0.01jk | 4.58 ± 0.07f | |
15 | Oued Laou | 0.22 ± 0.002m | 0.24 ± 0.003o | 1.85 ± 0.02l | |
16 | Ain Beida 1 (Mokrissat-Ouezzane) | 0.45 ± 0.01i | 0.50 ± 0.01k | 6.37 ± 0.13c | |
17 | Zoumi 1 (Mokrissat-Ouezzane) | 0.48 ± 0.001h | 0.54 ± 0.001i | 5.47 ± 0.006d | |
18 | Moulay Idriss Zerhoun 1 | 0.37 ± 0.002j | 0.41 ± 0.002l | 4.09 ± 0.01gh | |
19 | Moulay Idriss Zerhoun 2 | 0.37 ± 0.001j | 0.42 ± 0.001l | 2.60 ± 0.01j | |
20 | Moulay Idriss Zerhoun 3 | 0.59 ± 0.006e | 0.68 ± 0.01e | 6.66 ± 0.07b | |
CTCF: Condensed Tannins Content in Fresh powder, CTCD: Condensed Tannins Content in Dry powder, CTCP: Condensed Tannins Content in one fresh Pulp. The data represent Mean ± SE of replicates (n = 3). Values in the same rows carrying different letters are significantly different between treatments and control by Duncan’s multiple range tests at p ≤ 0.05.
Furthermore, we notice variations in polyphenols contents among wild and/or domesticated trees from the same locality. This is the case for Bni Hassane (trees 2 and 3), Mokrissat (wild trees 5, 6 and 7, domesticated trees 16 and 17), Nador (trees 9 and 10) and Moulay Idriss Zerhoun (trees 18, 19 and 20). Within a same location, altitude can change: for example, trees 2 and 3 from Bni Hassane grow at 330 and 876 m. This implies different environmental conditions (climate, soil…), which could influence the content of polyphenols [
Our results are in the interval of results of other studies on carob tree. Difference depends on genetic, geographical, environmental, physiological and cultural conditions, sample preparations, extraction protocol and method of analysis.
Actually, hermaphrodite cultivars appeared richer than female in total polyphenols content of carob pulp (18.0 vs. 41.3 mg GAE/g), in flavonoids and condensed tannins, especially (+)-catechin (10.3 vs. 5.5 mg/g) and gallic acid (1.8 vs. 1.1 mg) [
It was also found that the high growth activity in May is expressed both by higher photosynthetic rates and an increase in polyphenols, compared to June and October [
Benchikh et al. [
Small pieces of pods (0.5 - 1.0 cm) eluted with water (1:4) using peristaltic pump, carob pods reduced to fine powder and mixed with water at a ratio (1:4) during 2 h at 45˚C and particle size of 0.5 - 1.0 cm prepared as the previous powder were compared; the first resulted eluant and the two latter extracts were centrifuged at 3000 rpm and 0˚C for 30 min; resulted extracts contained 0.06, 0.11 and 0.07 g TAE/100 mL of extract [
Optimization of yield can be accomplished by applying and controlling parameters of some processes like roasting. Kibbled carob was roasted at 135˚C, 150˚C and 165˚C during 0, 5, 10, 15, 20, 30, 45, 60, 75 and 90 min. Roasted samples were then ground, sieved and stored at 4˚C till extraction and analysis. Total phenolic content of non- roasted kibbled carob was 0.570 g/100 g of dry matter and increased up to 0.865, 0.986 and 1.131 g/100 g during the roasting process at 135˚C, 150˚C and 165˚C, respectively. Total polyphenols content was almost stable in the initial stage and gradually increased to a maximum level up to 75 min [
Different methods for polyphenols extraction are reported in literature including conventional methods using solvents, ultrasound extraction [
Kumazawa et al. [
Pod powder has been extracted by different solvent systems: 80% ethanol [
Benchikh and Louailèche [
In another study, water, ethanol, acetone and ethyl acetate were evaluated. Maximum quantities of polyphenols were obtained by 10% aqueous ethanol and maximum quantities of proanthocyanidins were obtained with 70% aqueous acetone [
A series of non toxic solvent systems, composed of water/ethanol, acidified and non acidified with either acetic or citric acid, were tested for their efficiency in extracting polyphenols from dried and ground carob kibbles. It was found that 30% ethanol was the best solvent system, providing extracts with high total polyphenolic content (9.32 ± 0.78 mg GAE/g of dry powder) and high antioxidant activity. The highest yield of total polyphenols was achieved at 60˚C [
In addition, carob kibbles (by-product of carob been gum production) from Portugal were submitted to an aqueous extraction to extract sugars, and supercritical fluid extraction was applied to the solid residue of that aqueous extraction, by using compressed carbon dioxide as the solvent and 80% ethanol as a co-solvent. Pressure and temperature were studied in the ranges 15 - 22 MPa and 40˚C - 70˚C, respectively. Particle diameter and co-solvent percentage are in ranges of 0.27 - 1.07 mm and 0% - 12.4%, respectively, as well as the flow rate of supercritical CO2 between 0.28 and 0.85 kg/h. The best results were found at 22 MPa, 40˚C, 0.27 mm particle size, about 12.4% of co-solvent and a flow rate of 0.29 kg/h [
In the present study water was used as solvent system for polyphenols extraction, followed by acetone. It was proved that it attacks bonds established between polyphenolic structures and other macromolecules like proteins and lipids. Furthermore, reports about carob pod tannins have shown that they had a low solubility in solvents like methanol and ethanol. Actually, carob pod tannins are strongly polymerized with molecular weight attending 32,000 g/mol and have non-porous granular form [
Methods of analysis can also explain the variation of contents. In this work, the condensed tannins content have been determined the proanthocyanidin assay (butanol- HCl method). There is also the vanillin assay (vanillin-H2SO4 method) that provides the quantity of flavanols including catechins and proanthocyanidins [
In the present study, pods from Moroccan carob were found to have obvious variability of polyphenols content. Indeed, the twenty studied trees showed great variability in total polyphenols, flavonoids and condensed tannins contents.
Generally, it was found that pods powders from wild trees are richer in polyphenols than those from domesticated trees. Nevertheless, the second one has sometimes a tendency to reach the content of the first one. In addition, polyphenols content in the fresh pulp depends on its size and weight.
Also, pods from trees in the same region showed variable contents in polyphenols, flavonoids and condensed tannins.
This report is the one among others researches which proves that carob pulp (kibbled pod), especially from Morocco, is a rich source of polyphenols, shown to be natural bioactive compounds with several benefits. Also, it offers a tool for socio-economic development of local populations as an implement to some government institutions interested by protecting, valorizing genetic resources and developing the regional information system for the management of biodiversity. Moreover, the high pulp content of polyphenols found may encourage people to consume carob deseeded fruits.
We thank the Francophone University Agency (FUA) which financed this research in the form of a Research Grant (N/REF.: CE/GR/662/2013) within the framework of the Doctoral and Postdoctoral Fellowship Program “Eugen Ionescu” 2013/2014 set up by the Romanian Government.
El Bouzdoudi, B., El Ansari, Z.N., Mangalagiu, I., Mantu, D., Badoc, A. and Lamarti, A. (2016) Determination of Polyphenols Content in Carob Pulp from Wild and Domesticated Moroccan Trees. American Journal of Plant Sci- ences, 7, 1937-1951. http://dx.doi.org/10.4236/ajps.2016.714177