Studies on extraction from Avocado's waste biomass to generate process design alternatives of valuable products

Avocado (Persea americana) seeds of the cultivar Hass, cultivated in Brazil and Mexico, were study for extraction purposes, in order to determine the amount and the composition of valuable extracts. The avocado seeds, which represent about 23 % of fruit weight, have even higher antioxidant activity than its pulp. This study carried out the extraction of seed oil by using two extraction techniques: Soxhlet liquid-solvent extraction and supercritical fluid extraction (SFE). Soxhlet extraction (for a period of 6 hours) involved three solvents: hexane, ethanol and ethyl acetate. Ethanol presented the highest extraction yield, for both particle sizes studied and for both seed types (Mexican and Brazilian), being the highest yield of 10.3 ± 0.3% for the smaller particles, referring to the Brazilian seeds. This result indicated that the seed’s extract might be high on content for polar components. The SFE was performed using supercritical carbon dioxide (scCO2) as a solvent and after some preliminary experiments, ethanol revealed to be the best cosolvent. The highest extraction yield (for particle size between 0.42 and 0.60 mm) was 6.9% for the conditions of 80єC, 25 MPa and a mass ratio of 1.5:1 (referring once again to the Brazilian seed). Comparing both methods, Soxhlet reached higher yield, although it implies a greater energy, time and solvent consumption than SFE