Evaluation of Techniques for Intensifying the Process of the Alcoholic Extraction of Coffee Ground Oil Using Ultrasound and a Pressurized Solvent

• Published in: Foods Vol. 11; no. 4; p. 584
• Main Authors: Toda, Tatiane Akemi, Santana, Ana Julia Morelli, Ferreira, Julieta Adriana, Pallone, Eliria Maria de Jesus Agnolon, Aguiar, Claudio Lima de, Rodrigues, Christianne Elisabete da Costa
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 17.02.2022; MDPI
• Subjects: Bulk density; Coffee; coffee byproduct; Ethanol; Food science; green solvent; instant-coffee residue; Lasers; Particle size; PCA; Photomicrographs; PLE; Scanning electron microscopy; Solvents; Sonication; UAE; Ultrasonic imaging; Ultrasound; Vegetable oils; Brazil; United States > US; Japan; multistage cross-current extraction; PLE; UAE; coffee byproduct; instant-coffee residue; green solvent; PCA
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods11040584

Ultrasound-assisted extraction (UAE) and pressurized liquid extraction (PLE) techniques were evaluated and compared with conventional extraction for obtaining spent coffee ground oil (SCGO). The use of absolute ethanol (ET0) and hydrated ethanol (ET6) as solvents, two levels of SCG mass ratio:solvent, 1:4 (U4) and 1:15 (U15), and ultrasound powers of 0, 200, 400, and 600 W were tested. ET0 and U15 resulted in higher extraction yields of SCGO (Y , 82%). A positive effect of sonication on Y was observed only for condition U4. UAE resulted in defatted solids (DS) with higher apparent density values, corroborating the increase in the amount of smaller diameter particles due to sonication. The micrographs showed changes in the surfaces of the solids from the UAE and PLE, although the crystalline structures of the DS were not altered. UAE and PLE, compared to conventional extraction, did not allow significant gains in terms of Y and, consequently, in the number of contact stages in an extractor configured in cross-currents.