Scientific Results

Novel configurations for a citrus waste based biorefinery: From solventless to simultaneous ultrasound and microwave assisted green extraction

Year: 2016

Authors: Gonzalez Rivera J., Spepi A., Duce C., Falconieri D., Ferrari C., Piras A., Tine M.R., Longo I.

Autors Affiliation: Department of Chemistry and Industrial Chemistry, University of Pisa,
Via G. Moruzzi 3, 56124 Pisa, Italy.
Fax: +39 050 2219260; Tel: +39 050 2219311

National Institute of Optics (INO), National Research Council of Italy (CNR), Via G. Moruzzi 1, 56124 Pisa, Italy

Istituto Tecnico Industriale Statale “Michele Giua”, Via Montecassino,
09100 Cagliari, Italy

Department of Chemical and geological science, University of Cagliari,
Cittadella Universitaria di Monserrato, S.S. 554, km 4, 500, 09042 Monserrato, Italy

Abstract: Innovative extraction configurations for the biorefining of a biomass waste (citrus peel) were developed in this work. Non-conventional energies, such as microwaves (MW) and ultrasounds (US), were directly irra- diated to the fresh orange peel using a versatile MW coaxial dipole antenna. This particular MW configur- ation enabled us to build two new extraction systems: (1) a coaxial solventless MW-assisted extraction (SMWAE) approach and, (2) a simultaneous ultrasound coaxial MW-assisted hydrodistillation (US-MWHD) method. The yield and chemical composition of the essential oils (EOs) of the orange peel obtained by the two innovative approaches were analyzed as a function of the extraction time and compared with those from coaxial microwave hydrodistillation (MWHD) and conventional hydrodistillation (CH). The EOs were chemically characterized by GC and GC-MS analysis. The residue mash was then used to extract pectin by a MW-assisted procedure. The structure and thermal stability of the pectin were investigated by FTIR and TG. The biorefining of EOs and pectin from a citrus waste maximises the benefits of our pro- posed green methodologies, which involve safe operability, faster processing and easy scalability. Furthermore, the energy consumed per unit mass of products in each step of the orange peel biorefining clearly showed that the most promising approach is SMWAE (since it is around 27 times lower than the CH approach). MWHD and US-MWHD also showed more than 60% energy savings compared to CH.

Journal/Review: GREEN CHEMISTRY

Volume: 18      Pages from: 6482  to: 6492

KeyWords: Microwave chemistry, biomass, biorefining, Ultrasounds, solventless
DOI: 10.1039/c6gc02200f

Citations: 20
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