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Home All issues Volume 29 (2022) OCL, 29 (2022) 9 Full HTML
Open Access
Issue
OCL
Volume 29, 2022
Article Number 9
Number of page(s) 13
Section Quality - Food safety
DOI https://doi.org/10.1051/ocl/2022002
Published online 11 February 2022

© M. Ibourki et al., Published by EDP Sciences, 2022

Licence Creative CommonsThis is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1 Introduction

Almonds [Prunus dulcis Mill. DA Webb] are one of the most important nut trees growing worldwide in terms of commercial production. The top producers are USA and some countries of the Mediterranean basin. Following the latest FAOSTAT’s release (FAOSTAT 2021), the almond world production is around 3.5 millions of tons. Morocco is one of the potential producers with a total production of 117 270 tons coming from a harvested area estimated at 190 612 ha. The bitter almond (Prunus amygdalus, var. amar) is inedible because of the presence of a glycoside called amygdalin that can be decomposed into glucose, benzaldehyde, and hydrocyanic acid and make the product non-edible. Bitter almond oil has important medicinal properties and it is used in pharmaceutical industry (Čolić et al., 2019). Sweet almond (Prunus amygdalus, var. dulcis) is the cultivated for its kernel, which forms the edible part of the nut. Sweet almond oil contains low level of free fatty acids, peroxides and phosphatides (Čolić et al., 2019). Chemical composition of almond kernels is well documented. Almond kernel is known to be of high nutritional value (Yada et al., 2013; Zahedi et al., 2020, Sakar et al., 2021a). Indeed, almond is considered as a valuable source of lipids (44–61% on fresh weight; 20–68% on dry weight), proteins (10 to 35%), dietary fiber, riboflavin, vitamin E, phytosterols, manganese, magnesium, copper, phosphorus and sugars (Roshila et al., 2007; King et al., 2008; Yada et al., 2011, 2013; Prgomet et al., 2017; Socias i Company and Gradziel, 2017; Čolić et al., 2019). It also contains a significant amount of bioactive compounds including flavonoids, phenolics and tannins making it a good natural antioxidant (Čolić et al., 2019). Almond oil has high concentrations of monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs), such as linoleic and oleic acids (Zahedi et al., 2020). Thanks to international breeding programs, several cultivars were released. Delayed blooming time is one the main goal of these breeding programs to overcome frost as the limiting factor for almond production (Sakar et al., 2017a). In modern Moroccan orchards, several commercial cultivars are grown. The most important are “Marcona”, “Tuono”, “Ferragnès”, and “Ferraduel” (Kodad et al., 2015). Following these authors, traditional orchards are dominated by almond seedlings mainly on marginal soils with a low productivity. However, these almond genotypes (seedlings) may offer an important germplasm to select superior genotypes to be included in breeding programs, for instance, owing to their promising pomological features. Little is known about Moroccan genetic diversity of almond genotypes especially in southern Morocco. Hence the originality of this work, which aimed at (i), characterizing pomological and physico-chemical characteristics of some local almond genotypes growing and (ii) comparing sweet and bitter almonds originated from various agro-ecological areas.

2 Material and methods

2.1 Sampling

This study was carried out on ten almond genotypes. For each genotype, three healthy trees were chosen for fruit sampling. Among them, five genotypes are sweet almonds (Prunus amygdalus var. dulcis) and the five remaining belong to bitter almonds (Prunus amygdalus, var. amara). Fruit sampling was done at full ripening stage (BBCH89) according to Sakar et al. (2019a). Fruits (sweet and bitter) were harvested during July in 2019 from five agro-ecological areas of southern Morocco namely (Fig. 1): Tafraout, Igherm, Taliouine, Tiznit, and Essaouira. Geographical position as well as climatic data of these areas are presented in Table 1.

thumbnail Fig. 1

Location of sampling sites.
Table 1

Geographical and climatic data for the sampling agro-ecological areas.

2.2 Sample processing

At the laboratory, collected almond samples were manually cracked to release the kernels (fruit edible part) as described by Sakar et al. (2019b). Afterwards, the kernels were crushed using an electric grinder. Finally, the powders were stored in plastic bottles at room temperature until use.

2.3 Chemicals and apparatus

Nitric acid, hydrochloric acid, methanol, potassium hydroxide and hexane were all reagent grade. For each of evaluated elements (Cu, Zn, Fe, B, Mn, Mg, Ca, Na and K), a standard solution of 1000 μg/mL dissolved in 2% (v/v) HNO3 supplied by Merck Millipore (CertiPUR, Darmstadt, Germany) was used as a stock solution for a calibration purpose. Stock solutions were stored in the fridge at 4 °C. Ultrapure water with maximum resistivity of 18.2 MΩ/cm, obtained from a Milli-Q Millipore system (Darmstadt, Germany) and Argon alpha-gas (purity higher than 99.995) supplied by Air liquid were used. Minerals were determined using a Perkin Elmer Model Optima 8000 DV spectrometer (Waltham, USA), equipped with a charge-coupled device (CCD) detector. A Gem Tip, Cross-Flow II nebulizer coupled with the Scott-chamber was used as a sample introduction system.

2.4 Physical kernel traits measurements

Before starting measurements, broken, damaged or immature almond kernels were removed. Fruit physical traits were carried out on sub-samples of 30 kernels from each genotype. Axial dimensions: length (KL); width (KW), thickness (KT), were measured on individual fruits with a digital caliper reading to 0.01 mm. Similarly, kernel weight (W) was measured using electronic balance with a precision of 0.01 g (Sakar et al., 2019b; Sakar et al., 2020).

2.5 Proximate composition

Proximate composition analysis was carried out on the powder of almond kernels. Moisture content (MC) was determined using an oven. Five grams of powder was placed in a ventilated oven at 103 °C until reaching a constant weight. Nitrogen content was determined by Dumas Method using an elementary analyzer LECO FP628 (LECO Corporation, Saint Joseph, MI, USA), protein content (PC) was estimated by multiplication the nitrogen value obtained by conversion factor 6.25. Ash content (AC) was determined by calcination of 5 g of sample powder in muffle furnace at 550 °C for six hours. Oil content (OC) was determined using two methods firstly; Soxhlet apparatus; 20 g of powder was subjected to extraction with hexane for 8 h. The solvent was partly removed in rotary vacuum evaporator at 45 °C, and also press extractor. The rest of the solvent was removed under stream of nitrogen to a constant weight to determine the OC gravimetrically. The extracted oils were filtered and kept in dark glass bottles at 4 °C until analysis for fatty acids. Carbohydrates content (CC) was obtained according the following equation:

Energy value (EV) (expressed as kcal/100 g dry basis) was computed from values of MC, AC, PC, OC (Soxhlet extracted), and CC using the following equation:

2.6 Minerals determination

Digestion of plant material was carried out using microwave assisted digestion speed-wave (BERGHOF, Germany). Kernel powder (0.3 g) was weighed in Teflon vessels then 8 mL of nitric acid (HNO3) (65%) and 2 mL of oxygenated water (H2O2) (30%) were added, then inserted in the mineralizer and the mineralization program was launched. A clear solution was obtained at the end of the program was diluted to 25 mL and then injected into ICP-OES.

2.7 Fatty acids composition determination

A mixture consisting of 1 g of oil, 10 mL of methanol, and 0.4 mL of 2 N potassium hydroxide was prepared, esterified by boiling under reflux for 10 minutes and cooled, then 2 mL of hexane were added to the mixture and washed with distillated water. Finally, hexane layer containing fatty acid methyl esters (FAMEs) was collected and analyzed gas chromatography (Agilent-6890). This later were equipped with a capillary column CP-Wax 52CB (30 m × 250 μm i.d., 0.25 μm film thickness). The operating conditions of GC-FID during this study were as follow: helium as carrier gas, 1 mL/min of total gas flow rate, 170 °C was the initial oven temperature and 230 °C was the final, temperature gradient was 4 °C/min, injector and detector temperature was set at 220 °C and the injection volume of the samples was 2 μL in a split mode (split ratio 1:50). The results were expressed as the relative percentage of the area of each fatty acid peaks (Gharby et al., 2020).

2.8 Statistical analysis

All determinations and measurements were performed, at least, in triplicate. The averaged values were calculated, and results were reported as means ± standard deviation (SD). Principal component analysis (PCA) and correlations matrix were carried out on mean values. Cluster analysis was performed on mean values through Euclidean distance to reveal similarity among studied genotypes. All statistical analyses were made through the Statgraphics Centurion XVII (StatPoint Technologies, Inc., Virginia, USA).

3 Results and discussion

3.1 Physical fruit traits

Along with chemical composition, the morphological aspect of an agricultural product is important since it influences consumer acceptance. The most research works focus in almond fruit is devoted to its chemical composition and little is given to physical fruit traits (Sakar et al., 2020). In this study, four morphological aspects; weight, length, width and thickness were investigated, the results are shown in Table 2. The obtained results showed that kernel weight varied slightly from an origin to another, the lowest value was 0.51 ± 0.15 g found in bitter almond from Tiznit and the highest one was 1.03 ± 0.18 g obtained in sweet almond from Taliouine, our results were lower than those reported by Sakar et al. (2020) for some commercial cultivars grown in northern Morocco. Length showed also a small variation between the studied agro-ecological areas, and ranged from 15.83 ± 0.65 mm measured for sweet almond from Tiznit to 21.27 ± 2.41 mm measured for sweet almond from Taliouine. For width, the results exhibited a good homogeneity between the obtained values for all the studied areas, and ranged from 9.75 ± 0.53 mm obtained in sweet almond of Tiznit to 13.76 ± 1.05 mm obtained in sweet almond from Taliouine. Regarding thickness the obtained results showed a small variation among studied areas, and from one genotype to another. The lowest value was 5.28 ± 0.77 mm found in bitter almond of Essaouira, and the highest was 7.35 ± 0.68 mm found in bitter almond of Tiznit.

Table 2

Fruit physical traits in almond kernels in the studied ten genotypes: weight (KH); length (KL); width (KW); thickness (KT).

3.2 Proximate composition

The determination of almond chemical composition is of a great importance since it allows consumers to know the nutritional value and the quality of this product. Moisture, protein, oil content and ash were determined in this study, and the obtained results were summarized in Table 3. MC of the studied samples showed relatively small variations between samples and ranged from 2.55 ± 0.38 in bitter almond of Tafraout to 4.34 ± 1.16% in sweet almond of Tiznit with an average of 3.32 ± 0.23%. Indeed, MC values of studied almond genotype showed small variations between sweet and bitter almond. Our results were similar to those found in some Turkish almond genotypes (2.25–3.70) by Şimşek et al. (2018). PC varied usually from 10% to 35% (Socias i Company and Gradziel, 2017), and almond kernel was considered as a protein-rich food (Roncero et al., 2020). The values obtained in this study ranged from 17.14 ± 2.14% found in bitter almond from Tafraout to 25.12 ± 1.23% found in sweet almond from Tiznit, with an average of 21.08 ± 1.82 g/100 g for solvent extraction. Values obtained for the cake extracted by press were different to those found for solvent extraction. Our results were in line with those reported in previous studies: from 20.81 to 25.99 g/100 g found in samples from Turkey (Şimşek and Kizmaz, 2017), 14.1 ± 0.09 to 35.1 ± 1.87 g/100 g found in Moroccan samples (Kodad et al., 2013), and 18.5 to 24.0 g/100 g in samples from California (Yada et al., 2013). According to these results and because of high protein content of almond, this product could be used as a dietary supplement to fight proteins deficiency and also for people suffer from hypertension (Şimşek et al., 2018). Regarding crude oil (OC), almond kernel is known to be particularly rich in oil and vary between 48 to 67 g/100 g of kernel dry weight (Abdallah et al., 1998; Kodad and Socias i Company, 2008; Sathe et al., 2008; Sakar et al., 2017b, Şimşek et al., 2018). According to our results, solvent extraction showed that all samples were rich in oil with little variations from an origin to another. Sweet almond from Tiznit displayed the lowest value (51.12 ± 2.99 g/100 g), while the highest value (56.26 ± 3.22 g/100 g) was found in sweet almond from Tafraout. These outcomes were consistent with those reported by other authors for almonds from Turkey (43.50 to 55.70 g/100 g) as highlighted by Şimşek and Demirkiran (2010) and Özcan et al. (2011), Portugal (30.00 to 51.00 g/100 g) as outlined by Martins et al. (2000), and Morocco (52.6 to 58.7 g/100 g) reported by Kodad et al. (2014). As demonstrated by Kodad et al. (2010), while OC is under the genetic dependency, the environment factors (soil and climate) account for significant impacts on its variations. The OC values obtained by press extraction showed wide variations from 36.27 ± 5.20 to 61.89 ± 0.74%. Such variations could be ascribed mainly to kernel moisture level as well as genotype. The results obtained for ash content showed a small variation between the analyzed samples, with lowest value of 5.11 ± 0.45% found in sweet almond of Igherm and the highest value 6.79 ± 0.52% found in sweet almond of Essaouira. The results for AC were higher than those reported by Şimşek and Demirkiran (2010) in almond from Turkey (2.45–4.42%), but closer to the values found by Moodley et al. (2007) in samples from South Africa (5.0 ± 0.1%). From the results cited above large variations in concentrations were found for oil and proteins content between the studied origins, this could be explained by environmental effect such as climatic conditions including weather and temperature variation, soil characteristics, growing conditions and also agronomic practices. Differences between genotypes of the same origins could be explained differences on the genetic background of each genotype. These findings were in good agreement with other studies, which previously observed differences in proteins and oil content as variety effect (Drogoudi et al., 2013).

Carbohydrates in almonds consist mainly of soluble sugars (mainly sucrose), starch and other polysaccharides such as cellulose and non-digestible hemicelluloses. According to previous studies, almonds are characterized by high carbohydrates content (CC) (Čolić et al., 2019). The total carbohydrates content usually ranged from 14 to 28% (Roncero et al., 2020). The obtained results in our study were calculated using CP and OC obtained by solvent extraction and they show that the analyzed samples were rich in carbohydrates. The carbohydrates content varied among origins and genotypes, the lowest value (13.34 ± 1.54%) was obtained in sweet almond from Tafraout, while the highest one (18.59 ± 2.22%) found in bitter almond from Igherm. Our results were lower than those reported in almonds from South Africa (28.0 ± 0.6%) as reported in Moodley et al. (2007). The variation of the carbohydrates content has already been linked to different factors such as cultivar, origin and harvest time (Yada et al., 2013; Roncero et al., 2020). The carbohydrates content determined herein for almond kernels was lower than that reported in previous studies (Moodley et al., 2007; Akpambang et al., 2008).

Energy value (EV) was also estimated during this study. Almost no variations were seen among studied samples, the lowest value was 549.80 ± 37.04 kcal/100 g found in sweet almond from Tiznit, and the highest one (591.03 ± 38.65 kcal/100 g) was recorded in better almonds from Tafraout. Our results were very close to those reported in US Department of Agriculture, Agricultural Research Service (USDA, 2010).

Table 3

Moisture content (MC, %), protein content of solvent (PCs, %) and press extracted cake (PCp, %), oil content extracted by solvent (OCs, %) and press extractor (OCp, %), ash content (AC, %), carbohydrate content (CC, %), and energy value (EV, kcal/100 g) of the studied genotypes grown under five different agro-ecological areas.

3.3 Mineral composition

Minerals are involved in various metabolic and physiologic processes of living organisms; their proper functioning requires the supply of well-defined quantities of these metals (Williams, 2005; Dronkelaar et al., 2018; Ceccanti et al., 2021). Indeed, insufficient intake or excess of minerals and trace elements may result in an alteration of the immune system and can eventually lead to clinical symptoms; adequate intake is required to preserve a healthy immune system (Wintergerst et al., 2007). In plants, minerals are known to be involved in the synthesis of organic compounds (Özcan, 2006). In almond kernels, minerals have been extensively studied in contrasting geographical regions (Schirra et al., 1994; Özcan, 2006; Özcan et al., 2011; Drogoudi et al., 2013; Yada et al., 2013; Şimşek et al., 2018; Ibourki et al., 2019). It is widely evidenced that almond kernel is a good source of minerals (Socias i Company and Gradziel, 2017; Roncero et al., 2020). The amount of the minerals studied in the sweet and bitter almond cultivars are shown in Table 4. According to the obtained results among the major-elements group constituted by K, Ca, P, and Mg following to the high requirements of these elements for plants, K was the most abundant element in all samples with concentration ranged from 9796.08 ± 793.49 mg/kg found in bitter almond of Igherm to 14 197.84 ± 1150.03 mg/kg found in Sweet almond of Essaouira, the same observation has already been noted by Roncero et al. (2020). P was the second most abundant element and ranged from 8190.75 ± 663.46 mg/kg found in sweet almond of Tafraout to 11 061.68 ± 895.96 mg/kg found in bitter almond of Tiznit. Ca was in third position and ranged from 3067.53 ± 248.47 mg/kg in bitter almond of Essaouira to 5404.93 ± 437.79 mg/kg found in sweet almond of Tiznit. Mg content was similar to that of Ca and ranged from 4002.85 ± 324.22 mg/kg found in sweet almond of Essaouira to 5101.72 ± 413.23 mg/kg found in bitter almond of Tiznit. The remaining minerals were found in small quantities as follows: Na (150.73 ± 13.18 to 271.64 ± 22.13 mg/kg), Cu (10.96 ± 1.96 to 22.12 ± 1.79 mg/kg), Fe (60.01 ± 5.40 to 85.19 ± 6.90 mg/kg), Zn (56.03 ± 4.53 to 77.53 ± 6.28 mg/kg), Mn (20.73 ± 1.67 to 31.56 ± 2.55 mg/kg), and B (20.47 ± 1.47 to 40.92 ± 3.12 mg/kg). These outcomes were consistent with results reported in other study (Wang et al., 2019). Important variations were seen among genotypes and origins as evidenced in Table 4. Considerable variations were observed for all elements as a function of geographic origin. This was consistent with what was previously reported by other authors for various plants and plant foods (Faez et al., 2013; Ibourki et al., 2021a, 2021b, 2022). These variations could be explained by the diversity of the mineral composition of soils for each origin, ecological factors, agronomic practices, water source, irrigation practices and also fertilizer component (Şimşek et al., 2018) as well as the ripening stage (Schirra et al., 1994; Yada et al., 2013). The differences found between the genotypes growing under the same conditions are probably controlled by genetic component (Drogoudi et al., 2013; Yada et al., 2013).

Table 4

Mineral content (mg/kg) of ten almond kernel flour genotypes grown under five different agro-ecological areas.

3.4 Fatty acid composition

The fatty acid (FA) composition is an important indication of nutritional value of the oil (Gharby et al., 2017, 2018). In order to highlight the differences between almond FA composition of genotypes obtained from different origin and evaluate the effect of extraction method on this component, we determined the fatty composition profile. Table 5 shows the obtained results of FA composition of different genotypes almond oil obtained by press and solvent. In general, almond oil is known to be rich in unsaturated fatty acids with a high content of oleic acid (63 to 78%) and linolenic acid (12 to 27%) and (Kodad and Socias i Company, 2008). Owing to this composition almond oil is considered very healthy (Barreca et al., 2020). In this study eight fatty acids namely: myristic acid C14:0, palmitic acid C16:0, palmitoleic acid C16:1, stearic acid C18:0, oleic acid C18:1, linoleic acid C18:2, linolenic acid C18:3 and arachidic acid C20:0 were analyzed in almond oil (Tab. 5). The obtained results showed similar fatty acid profiles among almond oil from various genotypes and origins. However, LSD’s test revealed significant differences (p ˂ 0.05) among some genotypes in terms of the investigated fatty acids. Similarly, important variations were seen among almond oil samples achieved using solvent and press extractions. Indeed, oleic acid, linoleic acid and palmitic acid were predominant in almond oil regardless of genotype, origin and extraction method, the same findings were already noted in previous study (Kodad et al., 2010). Oleic acid was the most abundant in all genotypes for both kinds of extraction with important variations (64.2–71.1%) for pressured oil and oil extracted by solvent (65.4–73.23%). This is in line published literature regarding the dominance of oleic acid in almond oil (Sakar et al., 2021a) and other vegetable oils such olive oil (Gharby et al., 2021), argan oil (Boukyoud et al., 2021), and date palm seed oil among others (Ibourki et al., 2021b). Linoleic acid was the second most abundant for both oils obtained by press (18.01 to 25.32%) and solvent extracted oil (14.7 to 24.12%). However, the studied almond oil samples contained very small amounts of linolenic acid. It is even absent in some samples. It is a very oxidizable molecule. This fatty acid can be used to detect the adulteration of almond oil with other vegetable oils rich in linolenic acid such as soybean and rapeseed oils (Gharby et al., 2020). Both myristic and arachidic acids were not detected in all studied samples extracted using solvent and press extractions.

The major saturated fatty (SFA) acids, was palmitic acid representing in third position with variation ranges from 6.3 to 7.08% and from 6.5 to 8.1% for pressured oil and that extracted by solvent, respectively. Stearic acid was detected in small amount in press extracted oil (1.8 to 3.1%) as well as solvent extracted oil (2.1 to 3.4%). Palmitoleic acid was found in a very small amount in oil extracted by pressing (0.3 to 0.5%) and in solvent extracted oil (0.3 to 0.67%). These findings showed that extraction type effect was of a lesser magnitude. Regarding origin effect, slight variations were seen between genotypes belonging to the same origin, however, genotypes from different origins showed important variations of FAs content except for C16:1 the content of different origins were very similar. These differences could be explained by climatic conditions and agronomic practices (Sakar et al., 2021a).

Table 5

Fatty acid profiles of almond oil obtained by press and solvent extraction.

3.5 Principal component analysis

PCA was used as a multivariate statistical analysis with the aim to discriminate among genotypes and various origins (sites). The first three components were retained since they explained around 68% of total data variance. As it can be seen in Figure 2A, the five origins were separated through the first two components accounting for about 50%. Figure 2B represents mean values of geographical origins plotted on the surface delimited by PC1 and PC2. Furthermore, Tiznit seemed to interact with higher values of MC, EV, KT, P, Mg, K, Zn, and Mn, while, Tafraout together with Taliouine and Essaouira were associated to the best records of AC, Cu, Ca, W, PC. Igherm was characterized by higher levels of CC, OC, and KL. As evidenced in Figures 2C and 2D, the investigated almond genotypes were separated through the second component (PC2 = 21.50%) and the third component (PC3 = 17.05%). Moreover, better almonds were marked by higher levels of MC, OC, CC, AC, EV, KT, Zn, Mg, Na, and P. In contrast, sweet genotypes were linked to great values of PC, KW, KL, W, Fe, K, and B. PCA is widely in use in many fields such as pomological studies, chemometrics, crop physiology among others (Boussakouran et al., 2019; El Yamani et al., 2019a, 2019b, 2019c, 2020a, 2020b, 2020c, 2020d; Zeroual et al., 2021; Boussakouran et al., 2021; Sakar et al., 2021a, 2021b; Ibourki et al., 2022).

thumbnail Fig. 2

Principal component projections for the first three components that most impact investigated fruit traits. Blue segments represent dependent variables, while points plotted are mean values. W: weight; KL: kernel weight; KW: kernel weight; KT: kernel thickness; OC: oil content; CC: carbohydrates content; PC: protein content; AC: ash content; EV: energy value.

3.6 Cluster analysis

Cluster analysis was carried out on mean values to examine similarity among investigated genotypes based on their physical fruit traits, proximate composition as well as mineral profiling as illustrated in Figure 3. From these outcomes, our genotypes showed higher diversity. TLs presented higher dissimilarity with the remaining genotypes, IGs and TFs were similar to each other. In a similar way, there were important similarities among TFs, ESb, ESs, TLb, and IGb. In such a context, a genetic study seems to be very useful to compete this pomological study among local almond genotypes in southern Morocco.

thumbnail Fig. 3

Dendrogram conceived based on Euclidean distance in studied almond genotypes.

3.7 Correlation study

Spearman ranks correlation was performed on mean values to analyze association among studied parameters (Tab. 6). Based on these outcomes, important correlations were highlighted. Axial dimensions (KL, KW, and KT) were linked positively to each other on one hand and associated correlated with kernel weight (W). Likewise, EV had a negative correlation with CC. Also, KT was positively and significantly linked to Mg, Ca, and Mn. B was positively associated to PC and Cu and negatively correlated with Na. Mg had a positive significant correlation with Zn and Ca. P displayed a positive correlation with Na. The remaining correlations were low or insignificant. Similar trends of correlations were highlighted by other authors (Sorkheh et al., 2010; Sakar et al., 2019b). Correlation knowledge is very important for breeders and consumers. For instance, breeding for a desirable trait could foster the appearance or disappearance of another trait because of their correlation.

Table 6

Coefficients of correlation among investigate dependent variables.

4 Conclusions

In this study, we investigated the differences between ten almond genotypes (five of bitter and five of sweet almond) originated from five different areas in southern Morocco. The studied genotypes were compared in terms of physical fruits traits, proximate composition, mineral profiling and fatty acid composition. The obtained data exhibited a good homogeneity in terms of physical fruit traits, and slight variations were seen in proximate composition, minerals content. Similar fatty acid profiles were obtained for almond oil from various genotypes, origins and extraction method. The above results showed that investigated genotypes had important protein content, oil content, energy value, mineral composition and fatty acid composition of almond oil. Our genotypes showed promising features that should be considered for consumers and breeding purposes. Likewise, higher variability was highlighted among genotypes as revealed by multivariate statistical approaches (PCA and cluster analysis).

References

Cite this article as: Ibourki M, Ait Bouzid H, Bijla L, Aissa R, Sakar EH, Ainane T, Gharby S, El Hammadi A. 2022. Physical fruit traits, proximate composition, fatty acid and elemental profiling of almond [Prunus dulcis Mill. DA Webb] kernels from ten genotypes grown in southern Morocco. OCL 29: 9.

All Tables

Table 1

Geographical and climatic data for the sampling agro-ecological areas.

In the text
Table 2

Fruit physical traits in almond kernels in the studied ten genotypes: weight (KH); length (KL); width (KW); thickness (KT).

In the text
Table 3

Moisture content (MC, %), protein content of solvent (PCs, %) and press extracted cake (PCp, %), oil content extracted by solvent (OCs, %) and press extractor (OCp, %), ash content (AC, %), carbohydrate content (CC, %), and energy value (EV, kcal/100 g) of the studied genotypes grown under five different agro-ecological areas.

In the text
Table 4

Mineral content (mg/kg) of ten almond kernel flour genotypes grown under five different agro-ecological areas.

In the text
Table 5

Fatty acid profiles of almond oil obtained by press and solvent extraction.

In the text
Table 6

Coefficients of correlation among investigate dependent variables.

In the text

All Figures

thumbnail Fig. 1

Location of sampling sites.
In the text
thumbnail Fig. 2

Principal component projections for the first three components that most impact investigated fruit traits. Blue segments represent dependent variables, while points plotted are mean values. W: weight; KL: kernel weight; KW: kernel weight; KT: kernel thickness; OC: oil content; CC: carbohydrates content; PC: protein content; AC: ash content; EV: energy value.
In the text
thumbnail Fig. 3

Dendrogram conceived based on Euclidean distance in studied almond genotypes.
In the text

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