Fig Seeds as a Novel Oil Source: Investigating Lipochemodiversity Through Fatty Acids Profiling and FTIR Spectral Fingerprints

Abstract

Fig seeds (Ficus carica L.), a previously overlooked component of the fig fruit, have recently garnered attention as a valuable source of atypical vegetable oil and food-based ingredient. This study evaluated the oil content, fatty acid composition, and molecular FTIR-based signatures of 21 Ficus carica L. genotypes growing in an ex-situ collection. Gas chromatography analysis revealed high levels of linolenic acid (18.11 ± 0.255% to 42.276 ± 0.173%), followed by linoleic acid (27.75 ± 0.019% to 36.68 ± 0.046%). Palmitic acid (6.671 ± 0.006% to 8.908 ± 0.005%) and stearic acid (2.562 ± 0.009% to 4.160 ± 0.011) were the predominant saturated fatty acids (TSFA). The calculated oleic desaturation ratio (ODR), linoleic desaturation ratio (LDR), and ω6/ω3 ratio ranged from 0.466 ± 0.0284 to 0.710 ± 0.002, 0.330 ± 0.0998 to 0.595 ± 0.08, and 0.680 ± 0.283 to 2.025 ± 0.002, respectively. The desaturation efficiency from oleic to linoleic acid (ODR) was consistently lower than the desaturation from linoleic to linolenic acids (LDR) across all cultivars. ‘Aicha Moussa’ and ‘Amtala Arch’ exhibited the highest ODR and LDR (0.710 ± 0.002 and 0.595 ± 0.0779, respectively), potentially explaining the high C18:3 (linolenic acid) content in these cultivars. Notably, ‘Amtala Arch’ had an average linolenic acid content of 42.762 ± 0.173%. These findings highlight the significant lipochemodiversity within fig seeds, requiring further investigation into the potential for valorizing fig processing byproducts and creating new investment opportunities. FTIR-ATR spectroscopy coupled with chemometrics proved effective in characterizing molecular fingerprints, enabling both the rapid assessment of fig seed lipochemodiversity and enhanced sample authentication and classification.