Comparison of Oil Yield Extracted From Passiflora nitida Seed Flour by Different Methods

Seeds from the Passifloraceae family are sources of various bioactive compounds and can contain a high oil content depending on the extraction method used. Passiflora nitida is a plant native to Brazil. Although endemic to the Amazon biome, the species can also be found in the Cerrado and Caatinga due to its adaptability. The present study aimed to extract oil from Passiflora nitida seed flour (PNSF) using the Soxhlet and Bligh and Dyer methods and to compare their yields. For this purpose, ripe fruits were collected in Manaus (Amazonas, Brazil; 3°6′7″S, 60°1′30″W), washed, and separated into peel, seeds, and pulp. The seeds were lyophilized and vacuum-packed. Prior to extraction, the seeds were processed in an industrial blender. Due to the presence of pulp residues, the flour was purified using a 1:7.5 (w/v) ratio in 80% ethanol under agitation at 600 rpm
for 15 minutes at room temperature, followed by filtration. Subsequently, the filtered flour underwent a second purification, maintaining the same ratio but heated at 60°C for 15 minutes, then was filtered again, and dried in a forced-air oven at 35°C for 24 hours. The PNSF was subjected to Soxhlet extraction using 5 g of sample and 300 mL of diethyl ether as the extracting solvent at 40°C for 8 hours. The Bligh and Dyer method was performed with 5 g of sample, to which 5 mL of chloroform and 10 mL of methanol were added, vortexed for 3 minutes, followed by addition of 5 mL of chloroform and 10 mL of water, vortexed for 30 seconds, and allowed to stand for approximately 30 minutes. All tests were conducted in triplicate, and results were expressed as mean±standard deviation. To assess statistical differences, ANOVA followed by Student’s t-test was applied. Oil extraction by Soxhlet yielded 24.25%±0.07^a, whereas the Bligh and Dyer method resulted in 16.04%±0.27^b, showing a significant statistical difference (p<0.05). Therefore, Soxhlet proved more efficient in terms of yield; however, the continuous heating to which the matrix is subjected may compromise oil quality, promoting degradation reactions. Conversely, the Bligh and Dyer method, performed at cold temperatures, better preserves thermosensitive compounds but yielded approximately 33.85% less oil. These results highlight the need to optimize extraction conditions to combine high yields with preservation of chemical composition.