1. Introduction
Ceratonia siliqua L., also known as carob, belongs to the Fabaceae family, and it has been grown for numerous purposes such as reforestation, animal feeding, pharmacological uses, and, in some cases, human nutrition [1,2]. Carob trees are recognized for their tolerance to dry in semi-arid conditions, as well as their ability to thrive in various types of soil [2,3]. Originally from the Mediterranean region and Northern Africa, carob is a native species of the Mediterranean countries, such as Lebanon, Greece, Spain, and Morocco. Carob has had an important interest in the past that continues nowadays [4]. In the past, carob was a staple food, especially during times when other crops were in short supply. Its adaptability to different climates made it widely distributed in the Mediterranean basin and considered a dependable food source, adding to its historical significance as a staple food [3,5]. An estimated average of 56,639 tons of carob were produced worldwide in 2022 (FAOSTAT), with Europe accounting for 58.6% and Africa for 22% (FAOSTAT). Notably, Portugal, Italy, Morocco, Turkey, Greece, Cyprus, Lebanon, Algeria, Tunisia, and Croatia stand as the first major carob producers (FAOSTAT). Specifically, among the European countries, Portugal accounted for approximately 28.99% of the total production of carob (FAOSTAT).
Carob fruits can be defined as the mature pods of the Ceratonia siliqua tree, containing both pulp and seeds. Whereas, carob pulp is the sweet fibrous interior of the pod, excluding the seeds. Carob pulp and seeds are rich in bioactive functional components that are associated with various health benefits and hold industrial importance [6,7,8]. Thus, the economic significance of carob primarily arises from its seeds, widely recognized for their industrial importance due to diverse qualities and potential applications of locust bean gum (LBG; thickener E410) [9]. On the other hand, carob pulp is abundant in polyphenols (tannins, flavonoids, phenolic acids) and dietary fiber, along with other substances such as minerals, sugars, proteins, and vitamins [10,11]. In fact, the polyphenolic compounds found in the pulp are known for their antioxidant capabilities [12]. Additionally, carob pulp, given its nutritional value, shows great potential for use in diabetic-friendly foods and plays a role in regulating blood sugar levels [13]. In this context, D-pinitol is a significant component found in carob pulp and several studies have shown its promising source for medical applications [7,14]. This compound has been linked to different health benefits, including anti-diabetic, anti-cancer, antioxidant, anti-inflammatory, and immune- and hepato-protective properties, making it a valuable natural ingredient with multifunctional properties [7]. Furthermore, carob pulp has demonstrated a positive effect on human lipid profiles and controlling hyperlipidemia [10]. Finally, C. siliqua is a plant that has been used in traditional medicine throughout history to treat a variety of health problems, including diarrhea [15] and inflammation [16]. Especially, the pulp, which is rich in polyphenols and antioxidants, aids digestive health and blood sugar regulation, whereas the seeds are used to produce locust bean gum, and the leaves and bark are sometimes applied for wound healing and inflammation [17].
Ceratonia siliqua L. demonstrates notable variation in its agricultural, morphological, and technological features, which are influenced by several factors including agricultural practices [18]. These methods contribute to the preferential cultivation of traits. Nowadays, seed production is the main interest in carob cultivation due to its importance and usage in industry. However, pulp production could be a second option for profit in carob cultivation. In this context, studying the nutritional composition of carob assists in the targeted selection of varieties that align with specific applications, dietary preferences, and industrial requirements.
Several studies have explored the chemical composition and nutritional properties of different carob varieties in both the eastern and western parts of the Mediterranean Basin. The chemical composition of carob seeds, owing to their industrial and economic significance, has been extensively studied in various Mediterranean countries [19,20,21,22,23]. However, the chemical composition of carob pulp has received limited attention. Specifically, in the eastern part of the Mediterranean, the chemical composition of carob pulp has been assessed for Lebanese, Cypriot, and Turkish cultivars [24,25,26]. Conversely, carob pulp cultivars in the western part have been investigated in Sicily, Morocco, and Portugal [27,28,29]. To date, no study has comprehensively assessed and compared the pulp chemical composition of wild carob trees in both the eastern and western Mediterranean basins.
The current study aimed to assess the primary chemical constituents, including nutritional components, polyphenol content, and antioxidant activity, of carob pulp collected from wild trees present in the eastern (Lebanon) and western (Spain and Morocco) parts of the Mediterranean area. The assessment includes lipid content, protein content, moisture ash content, percentage of fiber, total polyphenols, antioxidant activity, and sugar constituents.
2. Materials and Methods
2.1. Chemicals
Water, methanol, acetonitrile, and chloroform of HPLC-MS grade were obtained from Panreac (Barcelona, Spain). Sodium carbonate, potassium persulfate, potassium chloride, Folin-Ciolcalteau reagent, DPPH reagent (1,1-diphenyl-2-picryl-hydrazyl), 2,2′-azino-bis (3-ethylbenzothiazoline-6 sulfonic acid) diammonium salt (ABTS), Trolox and the glucose, fructose, and sucrose standards were acquired from Sigma-Aldrich (Steinheim, Germany).
2.2. Plant Material Origin and Sample Processing
Eighty wild carob trees were assessed from various regions of Lebanon (n = 29), South of Spain (Andalusia region) (n = 29), and Morocco (n = 22) at altitudes ranging from 0 to 1800 m. Ripe carob pod materials were collected from each tree between 2019 and 2022. The samples were packaged and frozen in a room of −80 °C until processing. From each tree, 10 to 15 healthy carob pods were selected for analysis. The seeds were manually separated from the pods. For each tree, the selected pod used for the analysis was combined and subsequently ground into a powder using an industrial mill (The Knifetec™ 1095 Sample Mill, Foss, Hillerød, Denmark). Ground samples (0.5 mm) were preserved separately in hermetic plastic bags and frozen again until analysis.
2.3. Protein Content Analysis
Protein content was determined by elemental analysis following the protocol performed [30]. About 6500 µg of dried carob pulp were weighed into tin capsules (3.3 × 5 mm, IVA Analysentechnik e. K., Dusseldorf, Germany). The determination of % N values was performed using a Flash EA elemental analyzer with a TCD detector. A nitrogen-to-protein conversion factor of 6.25 was used to determine protein for each gram of material [31]. Using the conventional energy conversion factors—protein at 4 kcal/g, fat at 9 kcal/g, and carbohydrates at 4 kcal/g—the calorie content was determined [32]. In addition, total calories were determined as well as the calorie percentage for protein (Protein Calories Percentage = (Protein Calories/Total Calories ) × 100).
2.4. Lipid Content
Lipid content was determined by the Folch method [33]; 5 g of dried sample was extracted with chloroform:methanol (2:1, 30 mL × 2) in duplicate. The combined lipid extract was dried under reduced pressure and the total lipid content was calculated from the mass.
2.5. Fiber Content
From each sample, approximately 5 g of dry carob powder was prepared and sent to a reference laboratory (Laboratoio Proambi SLL, Pozoblanco, Córdoba, Spain) for fiber analysis. Results were given as a percentage of fiber.
2.6. Moisture, Ash, and Carbohydrate Content
Moisture and ash content were determined following the Association of Official Analytical Chemists (AOAC) methods [34]. The total carbohydrate content was calculated by difference (Carbohydrate content = 100 − (weight in grams [protein + fat + water + ash + fiber] in 100 g of food), following Triebold and Aurand [35,36].
2.7. Analysis of Mono- and Disaccharides
Glucose, fructose, and sucrose quantification were carried out using an HPLC-RID system (Thermo Fisher Scientific Ultimate 3000 HPLC System, San José, CA, USA) consisting of an HPLC pump, a RID detector, and an autosampler operating at 4 °C. The separation of the simple sugars was performed on a 250 × 4.6 mm i.d. Luna 5 µm NH2 column (Phenomenex, Torrance, CA, USA) and maintained at 40 °C. The mobile phases consisted of a mixture of acetonitrile and water (80:20) and were pumped at a flow rate of 1.5 mL/min using an isocratic method for 15 min. The identification of sugars was carried out using the respective standards and presented as grams per 100 grams of the dry weight. Quantification was performed by reference from 0.5 g/L to 45 g/L calibration curves of fructose, glucose, and sucrose. The samples for mono- and disaccharide quantification were extracted in duplicate using a methanol/acidified water mixture (80:20, v/v) containing 0.1% formic acid. An aliquot of each extract was stored in vials and injected into the HPLC for its analysis.
2.8. Total Phenolic Content
The extraction of polyphenols from carob pulp samples was performed in duplicate, homogenizing one gram of the sample using an Ultra-Turrax (Stauten, Germany) with 5 mL of a methanol/acidified water mixture (80:20, v/v) containing 0.1% formic acid. Following homogenization, the samples underwent centrifugation using Thermo Multifuge X1R Pro (Thermo Fisher Scientific, Waltham, MA, USA) at 3313× g for 15 min at 4 °C, and the resulting supernatants were carefully collected. A second extraction was performed using the remaining pellet. The obtained supernatants were combined. The samples were stored at −80 °C until analysis.
The measurement of total phenolic content (TPC) was conducted using the Folin–Ciocalteu assay, as described by Slinkard and Singleton [37] with modifications from Hervalejo et al. [38]. The results of the total phenolic content were reported in milligrams of gallic acid per gram of the dry weight sample (mg GAE/g DW).
2.9. Antioxidant Activity
2.9.1. ABTS Free Radical Scavenging Assay
The free radical scavenging activity was measured using the ABTS decolorization method with some modifications [39]. The ABTS assay was performed using a 96-well microplate measuring the absorbance of 730 nm after 15 min incubating in Synergy HTX Multi-ModeMicroplate Reader (Biotek Instruments, Winooski, VT, USA). Using known Trolox concentrations, a calibration curve is made to measure radical scavenging activity in Trolox equivalents. The antioxidant activity as per milligram of Trolox equivalents (TE) per gram of dry weight sample (mg TE/g DW) was determined by comparing the sample’s absorbance to the calibration curve. Each value represents the mean of six replicates.
2.9.2. DPPH Free Radical Scavenging Assay
Free radical DPPH (1,1-diphenyl-2-picryl-hydrazyl) scavenging capacity was determined using the previously described techniques [39]. After 50 min, the absorbance was recorded at 515 nm by using a 96-well microplate reader. The radical scavenging activity was expressed as a milligram of TEper gram of dry weight sample (mg TE/g DW). Each value is an average of six measurements.
2.10. Statistical Analysis
Statistical univariate analyses were performed using the free software R version 4.0.3 [40]. One-way variance analysis (ANOVA) was performed using the multcompView package [41]. Principal component analysis (PCA) was achieved and visualized using the MorphoTools2 package [42]. In addition, the Pearson correlation test was performed and the correlation plot was made using the corrplot package [43].
3. Results and Discussion
3.1. Protein Content
The protein content significantly varied depending on the origin of the samples. Thus, the protein content for Moroccan samples was the highest with an average value of 5.52 ± 1.76%, followed by Spanish samples with 4.55 ± 1.67% and the lowest one was for those samples coming from Lebanon (4.40 ± 0.98%). These values were similar to results obtained in previous studies, which reported a range between 1 to 6% [24,27,44,45,46,47]. The total calories of the wild carob pulps were 228.52 Kcal for Morocco, 227.83 Kcal for Spain, and 220.30 Kcal for Lebanon, respectively. According to the European Community Regulation 1924/2006 concerning nutrition and health claims, a food product qualifies as a “source of protein” if protein accounts for a minimum of 12% of its calorie content [48]. In this context, the calorie content determined from the protein percentage for 100 g of carob pulp samples from Morocco, Spain, and Lebanon is calculated as 22.08 Kcal (9.66%), 18.20 Kcal (7.99%), and 17.60 Kcal (7.99%) calories, respectively. Therefore, Moroccan, Spanish, and Lebanese wild carob pulp samples could not be considered as a source of protein, as they do not meet these nutritional requirements.
3.2. Lipid Content
Carob pulp is increasingly recognized as a beneficial ingredient in food formulations aimed at reducing fat intake due to its very low lipid content [49,50]. This characteristic, combined with its natural sweetness and high fiber content, makes it an appealing alternative to traditional flour like wheat and almond flour [51]. Significant differences were found in lipid content between samples obtained from Spain, Lebanon, and Morocco (0.27 ± 0.09%, 0.30 ± 0.15%, and 0.36 ± 0.09%; respectively). In addition, Moroccan wild carob pulp scored the lower amount of lipids (Table 1) ranging between 0.46 g/100 g DW and 0.66 g/100 g DW [52]. In this context, the carob pulp assessed in this study showed low-fat content, making it a healthier potential substitute for other ingredients in food formulation with similar sensory characteristics such as cocoa [47,53].
3.3. Carbohydrate Content
The values obtained in our study for carob pulp samples ranged between 80.59 and 91.11% (Table 1). The samples collected in Spain had a higher percentage (87.79 ± 2.06%) and those from Lebanon had a lower one (85.87 ± 2.49%).
3.4. Fiber Content
The percentage values obtained for the different carob pod samples ranged between 35.70 ± 0.81% and 36.00 ± 0.83%. No significant differences were found based on the geographical origin. Carob fiber content contributes to the nutritional value of carob products, providing dietary benefits such as aiding in digestion, promoting heart health, and potentially lowering serum cholesterol levels [54]. Thus, carob pulp samples of this study could be recognized as a rich source of dietary fiber, contributing to its nutritional value and potential health benefits.
3.5. Ash Content
The ash content for the analyzed samples ranged from 2.52 ± 0.65% to 3.28 ± 1.62% (Table 1). No significant differences were found in the ash content among the carob samples from the three studied countries. The ash content represents the inorganic residue post-ignition of organic matter and it is crucial for assessing mineral content and nutritional quality [55]. The percentage of ash content in this study was similar to the ones obtained in previous studies. Oumlouki et al. [56] indicated that ash content for Moroccan carob pulp samples ranged between 2.95% and 3.83%, whereas Algerian ones varied between 1.83% and 2.67% [57]. Additional studies such as the one performed by Youssef et al. developed in Morocco showed data of ash content of carob pulp for seven different places with values ranging between 2.44 and 3.89 g/100 g [45].
3.6. Moisture
Among the different parameters to estimate the nutritional value of foods, we need to analyze the moisture content [58]. In our study, significant differences were found in the moisture content of carob pulp among the different origins: Lebanon, Spain, and Morocco. Lebanese carob pulp scored the highest average moisture content (6.40 ± 1.43%) followed by the Spanish samples (4.87 ± 1.24%) and the Moroccan carob pulp samples (4.36 ± 0.77%). Moisture content is essential for predicting food behavior during processing, storage, and consumption [59]. In general, carob pod moisture content varies between 3% to 20% [2,57]. In this study, the percentage of carob moisture ranges between 4.36 ± 0.77% and 6.40 ± 1.43%. According to the literature, grinding carob pods could affect their equilibrium moisture content, with smaller particle sizes resulting in higher amounts in the powder [60]. Moreover, the moisture content of carob powder can be affected by environmental conditions, varieties, ripening, harvesting time, and the type of storage process [2,61]. Few studies have addressed the moisture in carob and specifically in carob pulp. In fact, we found several examples in the literature regarding the variability of this parameter, i.e., Moroccan carob collected in four different regions showed ranges between 8.97% and 10.41% [56].
3.7. Simple Sugar Content
Glucose, fructose, and sucrose are major sugars found in carob pulp [62,63], and they were identified and quantified in this study. The results revealed significant differences in these parameters depending on the geographical origin. The glucose concentration varied among the samples being the Moroccan carob pods those with the higher value, 3.16 ± 1.75 g/100 g DW followed by the Spanish and Lebanese ones (2.85 ± 1.16 and 2.03 ± 1.47 g/100 g DW, respectively) (Table 1). Moreover, regarding the sucrose content, Spanish carob pulp samples scored the highest content (28.10 ± 7.67 g/100 g DW), followed by Lebanese ones (25.60 ± 9.63 g/100 g DW), while Moroccan samples scored the lowest value (13.70 ± 6.41 g/100 g DW) (Table 1). With respect to the fructose content, we observed that the values ranged between 4.95 ± 1.99 g/100 g DW for Lebanese samples and 7.73 ± 1.72 g/100 g DW (Table 1) for the Moroccan ones. Sugar content in carob pulp is affected by several factors, such as genetic variation, environmental factors, and traditional agricultural practices [64]. In fact, distinct carob genomes adapted through different years to certain climate conditions across different regions of the Mediterranean area could contribute to sugar metabolism and content, including biosynthesis and decomposition of sugars [62,65]. Glucose plays a role as a vital cell nutrient, acting as a regulatory metabolite, impacting gene expression, and maintaining cell stability under environmental disturbance [66,67,68,69]. Moreover, it plays a crucial role in several physiological processes, including growth, stress responses, and energy signaling [70,71,72]. In addition, glucose is crucial for carob tree compensatory mechanisms to ensure a constant supply of energy for plant growth and development. Thus, this fact could explain glucose stability in this study across Lebanese, Spanish, and Moroccan carob pulp samples.
On the other hand, scarce studies have addressed the carob sugar content including the three main sugars found in carob pulp (sucrose, glucose, and fructose). The cases found in the literature agreed that sucrose was the predominant sugar in the carob pulp and powder from Bulgarian, Turkish, and Tunisian carob samples, with a concentration of 34.2, 16.5, and 33.70 g/100 g DW, respectively [63,73]. This finding aligns with the results of this study and with previous studies on Sicilian and Turkish carob samples [27,44]. In addition, Öncel et al. [74] revealed that carob pulp samples from Turkey contain significant levels of sucrose, glucose, and fructose (34.2 g/100 g DW, 11.1 g/100 g DW, and 6.5 g/100 g DW; respectively). As mentioned before, carob chemical compounds can vary based on different factors, especially the sugar content, which is taken into consideration in the selection of carob commercial varieties.
3.8. Total Phenolic Content and Antioxidant Activity
The total phenolic content (TPC) data showed that Spanish samples scored the highest value (12.70 mg/g DW), followed by Moroccan samples (8.48 mg/g DW), while the Lebanese samples scored the lowest one (5.05 mg/g DW) (Figure 1).
Data from the literature showed high variability on this parameter. Several authors reported lower values for two Cypriot carob pod varieties, Tilliria y Koumbota, (342.2 and 228.4 mg/100 g DW, respectively) [75]. Moreover, carob pulp samples from Athens and Rethimno in Greece showed lower TPC values (13.6 and 24.8 mg/100 g DW; respectively) [76]. In addition, female and hermaphrodite Portuguese carob varieties scored lower TPC, ranging from 1.6 g/100 g DW to 4.1 g/100 g DW, respectively [77]. On the other hand, studies focused on the ripening stage and reported that the TPC values of three different Algerian carob varieties were affected by the ripening stage [78]. Moreover, similar or even higher TPC results were observed for Cypriot carob samples, being 14.24 mg/g DW in ripe carob pulp [79] and 17.4 mg/g DW in mature pods [80].
DPPH and ABTS assays for antioxidant activity were used in this study, and the results are depicted in Figure 1. For both tests, the Spanish samples scored the highest values (DPPH = 25.10 mg TE/g DW, ABTS = 18.20 mg TE/g DW), followed by the Moroccan samples (DPPH = 16.70 mg TE/g DW, ABTS = 13.30 mg TE/g DW), while the Lebanese ones scored the lowest values for both techniques (DPPH = 12.40 mg TE/g DW, ABTS = 11.10 mg TE/g DW).
Ben Othmen et al. [62] studied the antioxidant activity using DPPH for Tunisian samples with values of 11.47 mg TE/100 g DW and Benchick et al. [78] obtained values of 1.26 mg TE/100 g DW for Algerian samples. The antioxidant activity measured by DPPH and ABTS assays and the TPC using the Folin Ciocalteu assay pursued the same change pattern for Spanish, Moroccan, and Lebanese samples, which confirms the well-known correlation between the total polyphenol content and the antioxidant capacity assessed. Interestingly, flavonoids, phenolic acids, and tannins are among the polyphenolic compounds found in carob plant pulp, seeds, and syrup, which greatly increase the fruit’s total phenolic content (TPC) and antioxidant capacity and may have positive health effects [81]. Phenolic acids like gallic and ellagic acids, along with well-known flavonoids like quercetin and kaempferol, are linked to antioxidant and anti-cancer properties [81,82,83]. These substances highlight carob’s potential as a natural antioxidant source for medications and functional foods.
3.9. Principal Component Analysis
The principal component analysis (PCA) was carried out using the 12 variables obtained in this study to assess the differences between the carob samples obtained from wild trees (Figure 2). The explained variance accounted for 45.7% of the total variance, 27.1% accounted for PC1, and PC2 accounted for 18.6%. Figure 2 displayed the weight of each studied variable in this study, showing their contribution to the carob individuals’ distribution along PC1 and PC2 (Table 2). The heaviest contribution for PC1 is for TPC, DPPH, and ABTS with an eigenvalue equal to 0.45, 0.49, and 0.48, respectively, while for PC2 are fructose, glucose, and sucrose with an eigenvalue of 0.52, 0.42, and −0.41, respectively (Figure 2 and Table 2). In addition, PCA analysis showed that three different groups can be extracted depending on the geographical distribution. Lebanese samples were grouped on the right upper side, characterized by the highest amount of moisture and sucrose. On the other hand, Moroccan samples were grouped on the bottom right part of the biplot, characterized by high fructose, glucose, lipid, and ash contents (Figure 2). Finally, the Spanish samples, where the majority were positioned to the left of the PCA biplot (Figure 2), were characterized by high carbohydrates, antioxidant activity (DPPH and ABTS), polyphenol content (TPC), and high sucrose, fructose, and glucose concentrations.
3.10. Variables Correlation
PCA analysis supported by Pearson correlation results showed several correlations between the studied variables (Figure 2 and Figure 3). In fact, the antioxidant activity assays, DPPH and ABTS, are positively correlated with TPC (r = 0.84 and r = 0.78, respectively) (Figure 2 and Figure 3). To a minor extent, carbohydrates are positively correlated with TPC (r = 0.27), DPPH (r = 0.33), and ABTS (r = 0.31) assays. As could be expected, fructose was positively correlated with glucose (r = 0.69) and weakly negatively correlated with sucrose (r = −0.14) (Figure 2 and Figure 3). Additionally, lipids have a low negative correlation with moisture (r = −0.11) or carbohydrates (r = −0.18), but they do have a positive correlation with ash (r = 0.20) and protein (r = 0.23). Ash content and fiber show a low positive correlation (r = 0.10), as does protein content (r = 0.14). Moreover, sucrose has a weak negative correlation with protein (r = −0.19), whereas it shows positive correlation with fiber (r = 0.25). Ash and moisture show no correlation (r = 0.03); however, carbohydrates and moisture have a negative correlation (r = −0.49).
Nutritionally speaking, glucose and fructose are both monosaccharides that are present naturally in fruits and vegetables, as well as the sucrose disaccharide. Studying these relationships could give insight into the metabolic pathways along carob pulp maturation and help in assessing the sweetness, quality, and potential use of carob in the market.
4. Conclusions
Carob pulp samples from wild trees in Morocco, Spain, and Lebanon were examined in this study. The highest levels of fructose, glucose, protein, and lipids were found in Moroccan samples, whereas the highest levels of carbohydrates, fiber, sucrose, phenolic content, and antioxidant activity were found in Spanish samples. The samples from Lebanon had the highest sucrose level, similar to those from Spain.
In this context, based on this finding, further genetic and climatic studies will be involved in the development of breeding programs to elaborate carob varieties with superior nutritional characteristics that could meet consumer demands and contribute to sustainable agriculture.
Conceptualization, M.A.E.C., G.P.-R., R.R.-S. and J.M.M.-R.; methodology, M.A.E.C., J.L.O.-D. and J.M.M.-R.; investigation, M.A.E.C., G.P.-R., J.L.O.-D., R.R.-S. and J.M.M.-R.; resources, G.P.-R., R.M.N.-C. and J.M.M.-R.; data curation, M.A.E.C., G.P.-R., J.L.O.-D. and J.M.M.-R.; writing—original draft preparation, M.A.E.C., G.P.-R. and J.M.M.-R.; writing—review and editing, M.A.E.C., G.P.-R., J.L.O.-D., R.R.-S., R.M.N.-C. and J.M.M.-R.; supervision, G.P.-R., J.L.O.-D. and J.M.M.-R.; project administration, G.P.-R. and J.M.M.-R.; funding acquisition, G.P.-R. and J.M.M.-R. All authors have read and agreed to the published version of the manuscript.
Not applicable.
Not applicable.
Data will be made available on request.
The authors are grateful to David Ariza Mateos from the University of Córdoba and to Jalal Kassout and Mohamed Ater from the University Abdelmalik Essaâdi (Tetouan, Morocco) for support for the research work, especially the collection and preparation of Moroccan plants samples.
The authors declare no conflicts of interest.
Footnotes
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Enlarge this image.Figure 1. Total phenolic content (TPC) and antioxidant activity charts for carob pulp samples studied. (Mo = Moroccan; Sp: Spanish; Lb: Lebanese). The letters a and b denote statistically significant differences between groups based on post-hoc analysis.
Nutritional (total content) and simple sugar contents studied were expressed in concentration ± standard deviation (SD) of carob pulp dry weight (DW) as well as minimum (Min.) and maximum (Max.) for each component in each country.
| Morocco | Spain | Lebanon | p-Value | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Nutritional | Mean | Min. | Max. | Mean | Min. | Max. | Mean | Min. | Max. | |
| Protein (%) | 5.52 ± 1.76 a | 3.02 | 9.74 | 4.55 ± 1.67 ab | 2.18 | 10.46 | 4.40 ± 0.98 b | 2.41 | 6.47 | * |
| Lipids (%) | 0.36 ± 0.09 a | 0.17 | 0.52 | 0.27 ± 0.09 b | 0.17 | 0.58 | 0.30 ± 0.15 ab | 0.16 | 0.85 | * |
| Carbohydrates (%) | 86.48 ± 2.57 ab | 80.95 | 91.11 | 87.79 ± 2.06 a | 81.83 | 90.67 | 85.87 ± 2.49 b | 80.59 | 90.67 | ** |
| Fiber (%) | 35.70 ± 0.81 | 34.30 | 37.20 | 36.00 ± 0.83 | 34.40 | 37.30 | 35.90 ± 0.90 | 34.20 | 37.60 | n.s. |
| Ash (%) | 3.28 ± 1.62 | 1.04 | 7.11 | 2.52 ± 0.65 | 1.28 | 3.95 | 3.02 ± 1.37 | 1.32 | 6.59 | n.s. |
| Moisture (%) | 4.36 ± 0.77 b | 3.34 | 6.69 | 4.87 ± 1.24 b | 3.22 | 9.08 | 6.40 ± 1.43 a | 2.94 | 9.33 | *** |
| Simple sugars | ||||||||||
| Fructose (g/100 g) | 7.73 ± 1.72 a | 4.42 | 11.65 | 7.50 ± 1.50 a | 2.62 | 10.37 | 4.95 ± 1.99 b | 2.20 | 9.44 | *** |
| Glucose (g/100 g) | 3.16 ± 1.75 a | 0.60 | 6.81 | 2.85 ± 1.16 ab | 0.48 | 5.86 | 2.03 ± 1.47 b | 0.43 | 6.59 | * |
| Sucrose (g/100 g) | 13.70 ± 6.41 b | 4.23 | 28.59 | 28.10 ± 7.67 a | 6.38 | 38.05 | 25.6 ± 9.63 a | 4.28 | 48.36 | *** |
***: Extremely significant (p-value < 0.001); **: Very significant (p-value < 0.01); *: Significant (p-value < 0.05); n.s.: not significant. The lowercase letters indicate statistical groupings, where means with the same letter are not significantly different and means with different letters are significantly different.
Eigenvectors of each studied variable for PC1 and PC2.
| PC1 | PC2 | |
|---|---|---|
| TPC | 0.45 | 0.19 |
| DPPH | 0.49 | 0.12 |
| ABTS | 0.48 | 0.05 |
| Fructose | 0.01 | 0.52 |
| Glucose | −0.06 | 0.42 |
| Sucrose | 0.08 | −0.41 |
| Lipids | −0.15 | 0.30 |
| Moisture | −0.20 | −0.35 |
| Ash | −0.23 | 0.22 |
| Fiber | −0.04 | −0.03 |
| Protein | −0.25 | 0.26 |
| Carboydrate | 0.38 | −0.07 |
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; Palacios-Rodríguez, Guillermo 1
; Ordóñez-Díaz, José L 2
; Rodríguez-Solana, Raquel 3
; Navarro-Cerrillo, Rafael M 1
; Moreno-Rojas, José M 2
1 Assessment and Restoration of Agricultural and Forestry Systems Research Group (ERSAF RNM360), Department of Forestry Engineering, Campus of International Excellence in Agri-Food and Agriculture—ceiA3, University of Córdoba, 14071 Córdoba, Spain;
2 Department of Agroindustry and Food Quality, Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA), Alameda del Obispo, Avda. Menéndez-Pidal, 14004 Córdoba, Spain;
3 Department of Agroindustry and Food Quality, Andalusian Institute of Agricultural and Fisheries Research and Training (IFAPA), Alameda del Obispo, Avda. Menéndez-Pidal, 14004 Córdoba, Spain;