Biochemical and Nutritional Profiling of Fig Seed Oils and Defatted Cakes by FTIR-ATR Spectroscopy

This study valorizes the defatted seeds and seed cakes of 21 fig genotypes, an atypical resource that remains scientifically underexplored. Few studies based on rigorous analytical approaches have been published regarding fig seed oils, and to our knowledge, no research has addressed the valorization of the seed cakes derived from these seeds. The major innovation lies in the combination of advanced analytical methods: chemical extraction using Soxhlet, gas chromatography with flame ionization detection (GC-FID) for fatty acid quantification, spectrophotometric colorimetric assays for phenolic and flavonoid compounds, and antioxidant activity evaluation using DPPH and ABTS radical scavenging tests. FTIR-ATR spectroscopy is used for the rapid, non-destructive, and reliable characterization of the oils, allowing for their discrimination based on molecular composition.

The results reveal significant intergenotypic variability, with linolenic acid content ranging from 18.11% to 42.76%, reaching a maximum in the "Amtala Arch" genotype. The dominant saturated fatty acids are palmitic and stearic acids. Total phenolic content ranges between 30 and 100 mg gallic acid equivalents per 100 g, flavonoids between 20 and 40 mg quercetin equivalents per 100 g, and antioxidant activity varies from 30% to 90%. The seed cakes show an interesting nutritional profile: 14% to 25% protein, 28% to 50% neutral detergent fiber (NDF), 2% to 5% residual lipids, and 4% to 6% moisture.

This research establishes a solid database on the biochemical and functional properties of fig seed oils and seed cakes. It offers new perspectives for sustainable valorization in nutraceutical and functional food sectors, fitting within a circular economy framework. The FTIR-ATR method confirms its potential as an innovative tool for rapid quality control.