Effect of dilution ration temperature salt addition centrifugal forece and ultrasound treatment on the process efficiency for extraction of oil from fresh avocado fruit pulp (Persea americana mill)

Abstract

This work aimed to investigate the effect of dilution ratio, salt addition, ultrasound treatment (temperature and duration), and centrifugal force on oil yield in the ultrasound-assisted centrifugal separation (UACS) method for oil extraction from fresh avocado pulp. The best condition of each factor was chosen by measuring the highest oil yield and considering time & cost savings. Specifically, the parameters were selected in a range of 9:1-27:1 (w/w) of water:solid ratio; 5-25% (w/w paste) of salt concentration; 35-75oC of ultrasonic temperature; 10-40 mins of ultrasonic duration; and 4000-8000 rpm of centrifugal force. As a result, the highest oil yield was 39.2±0.35% (d.b.) under dilution ratio (18:1), CaCO3 (15%), ultrasound treatment (55oC, 25 mins), and centrifugal force (8000 rpm). Meanwhile, the Soxhlet extraction method was used as a control to find the oil yield capacity of the fruit and compare it to the UACS method. The physicochemical characteristics of UACS oil were as follows: free fatty acid value (0.7±0.00%), peroxide value (4.82±0.28 meq O2/kg oil), saponification value (188.65±1.03 mg KOH/g oil), iodine value (80.32±0.23 g I2/100g oi), and total phenolic content (78.6±3.9 mg GAE/100g oil). Hence, this avocado oil is preferred in non-drying products, cosmetics, drugs, or soap