## 3 Results and Discussion
#### 3.1.4 Free Fatty Acids  
Free fatty acids were detected at low quantities in all examined fruits ranging from 1.8-5.0 mg/g, and from 1.05-1.7 mg/g in seed kernels. Major forms included palmitic acid (peak 34), linoleic acid (peak 35) and vaccenic acid (peak 36), with highest level of linoleic acid found in apricot bitter fruits AP-B\({}_{1}\)-F (3.3 mg/g) and AP-B\({}_{2}\)-F (3.1 mg/g) growing in muddy soil. Palmitic acid accounted for ca. 8-10% of dietary energy [41], whereas vaccenic acid is a positional and geometric isomer of oleic acid [42], a predominant trans fatty acid found in animal fat [43]. These results are in accordance with fatty acids composition previously reported in apricot fruits and seeds from other origins [44]. Multivariate Data Analyses of Primary Silylated Metabolites of the Different Apricot Cultivars Fruit and Seed Kernel Cultivated in Different Soil Types  
Chemometric tools were employed for the holistic assessment of primary metabolites heterogeneity amongst apricot cultivars, particularly given the significant number of peaks as variables in 8 selected specimens, each of which is represented by three biological replicates, and thus totaling 24 samples. Principal component analysis (PCA) was illustrated by two orthogonal PCs, accounting for 92% of the total variance prescribed by PC1 and PC2 (Figure 2A). Figure 2: Principal component analyses of silylated metabolites in seed kernel and fruit extracts as analyzed by GC-MS (\(n=3\)). (**A**) Score plot of PC1 vs. PC2 scores. (**B**) Loading plot for PC1 and PC2 contributing mass peaks and their assignments. AP-B1-F; Manshiet Al-Ammar bitter apricot fruits (Muddy soil), AP-B1-S; Manshiet Al-Ammar bitter apricot seeds (Muddy soil), AP-B2-F; Al-Amar Al-Kubra bitter apricot fruit (Muddy soil), AP-B2-S; Al-Amar Al-Kubra bitter apricot seed (Muddy soil), AP-M3-F; Nubaria mountain bitter apricot fruit (Sandy soil), AP-M3-S; Nubaria mountain bitter apricot seed (Sandy soil), AP-S2-F; Al-Amar Al-Kubra sweet apricot fruit (Muddy soil), AP-S2-S; Al-Amar Al-Kubra sweet apricot seed (Muddy soil). An obvious segregation between apricot seed kernels from fruits could be observed along PC1, with apricot seed kernel specimens positioned with negative score values (left side in PC1), whereas apricot fruit specimens clustered with positive score values (right side in PC1). Examination of the loading plot (Figure 2B) revealed that sugars _viz._ fructose, sucrose and glucose as well as acids _viz._ malic acid contributed the most for apricot fruit specimens' segregation with glucose, sucrose and fructose serving as major contributors to fruit sweetness, whereas amino acids _viz._ valine, leucine, isoleucine and glutamic acids found more abundant in apricot seed kernels suggestive for the sour taste of seed kernels compared to fruits. 2.1 Multivariate Data Analyses of the Primary Silylated Metabolites in Fruits and Seed Kernels Models  
For better segregation and to help identify variation within each organ, apricot seed kernel and fruit specimens were modeled separately one at a time (Supplementary Figures S1A and S2A, respectively. The seed kernels PCA model was illustrated by two orthogonal PCs, justifying 82% of the total variance, with clear discrimination of AP-S\({}_{2}\)-S (sweet seeds of apricot) and AP-M\({}_{3}\)-S (mild bitter seeds of apricot) at the left side of PC1 separable from other apricot bitter seed kernel specimens positioned in the middle and on right side of PC1. Examination of the loading plot (Supplementary Figure S1B revealed that variables corresponding to sugars _viz._ fructose, glucose and sucrose were found to be most enriched in AP-B\({}_{1}\)-S (seeds of Manshier Al-Ammar apricots (Muddy soil) and AP-B\({}_{2}\)-S (seeds of Al-Amar Al-Kubra apricots (Muddy soil) specimens. Modelling of nutrient metabolites suggest that cultivar type overcomes other variables in apricot seed kernels' segregation with sweet seed kernels being most distant from others.