(418bn) Improving the Sustainability of Antioxidants Production through Biorefinery Concept. the Blackberry Case

Castilla blackberry (Rubbus glaucus benth) is a fruit from the berry fruits family mainly cultivated in the Colombian departments of Cundinamarca, Santander, Huila and Antioquia. This fruit is cultivated in cold weather lands with average production yields of 11 ton/ha.[1] The ripe fruit is consumed in fresh and proceed in different forms; it is used for agroindustrial transformation such as juices, jams and cosmetics among other products.

The blackberry fruit is a source of fiber, vitamins, phytosterols, sulphur compounds and  carotenoids among others [2]. Some studies have reported the bioactive compounds of blackberry fruit and phenolic compounds such as anthocyanins and ellagitannins [3] that exhibit antioxidant properties. Total content of phenolic compounds are related to the ripening grade, harvesting conditions, weather conditions, specie, etc. Different extraction technologies have been employed to obtain antioxidants, especially extraction with organic solvents and supercritical fluid extraction are the widely studied.

The organic solvents currently used for phenolic compounds extraction are ethylacetate, acetone, ethanol, methanol and hydroalcoholic mixtures among others. The operation conditions for these solvents are commonly high temperatures (approximately 60°C) which could lead to thermal degradation of the phenolic compounds with longer extraction times (between 5-24 hours) are required. The use of organic solvents needs an additional separation and recovering stage increasing the energetic requirements and the extraction costs. Due to its possible health effects some of these solvents have restricted in food, cosmetic and other industries [6] [7].

Supercritical Fluid Extraction (SFE) technology enhances the extraction yields and could be developed in less time than organic solvent extractions and reduce the recovering and separation costs. The obtained extracts are solvent free which are appropriated in food and cosmetics uses. Usually after SFE of the phenolic compounds the solid matrix is discarded with a lignocellulosic material which could be fully utilized.

The aim of this work is to present an approach for improving the sustainability of phenolic compounds extraction from blackberry residues through a biorefinery concept in which the phenolic compounds extraction is integrated to the productin of bioproducts, biofuels and bioenergy.

The Blackberry residues were experimentally characterized by measuring moisture content (AOAC 928.09 method), klason lignin content (TAPPI 222 om-83 method), acid-soluble lignin content (TAPPI 250UM-85 method) holocellulose content (ASTM Standard D1104 method), cellulose content (TAPPI 203 os-74 method) and ash content (TAPPI Standard T211 om-93 method). Then the phenolic compounds were extracted at 45°C and 300 bar and the phenolic content was evaluated using the Folin-ciocalteu assay measured at 765 nm wavelength. The antioxidant scavenging activity was measured using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method and measured at 515 nm wavelength . The experimental results allowed found the appropriate compositions to formulate the biorefinery. All the experiments were carried out in the Biotechnology and Agrobusiness Institute at the Universidad Nacional de Colombia at Manizales.

The biorefinery from blackberry residues was evaluated using the commercial software Aspen Plus V8.0 (ASPEN TECHNOLOGY USA). In the first scenario the phenolic compounds extraction by supercritical fluids was evaluated. A second scenario where the phenolic compounds extraction by supercritical fluid was integrated to the production of ethanol, lactic acid, xylitol and energy was assessed as well. The economic evaluation was carried out using the commercial software Aspen Process Ecomomic Analyzer V8.0 (ASPEN TECHNOLOGY USA) taking into account the Colombian context with an annual interest rate of 17% and an income tax of 25%, with electricity and water costs according to the case study conditions. Furthermore the evaluation was made for a period of 10 years using the straight-line as depreciation method. The environmental evaluation was made through the methodology proposed by the Environmental Protection Agency (EPA) Waste Algorithm Reduction (WAR). This tool evaluates the Potential Environmental Impact (PEI) of process from the mass and energy balances, this PEI is present per kg of product.

The obtained results lead to conclude that the biorefinery approach can improve the full utilization  of the blackberry residues with economic and environmental competitive advantages.

REFERENCES

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[6]      G. Spigno, L. Tramelli, and D. M. De Faveri, “Effects of extraction time, temperature and solvent on concentration and antioxidant activity of grape marc phenolics,” J. Food Eng., vol. 81, no. 1, pp. 200–208, Jul. 2007.

[7]      L. Laroze, C. Soto, and M. E. Zúñiga, “Phenolic antioxidants extraction from raspberry wastes assisted by-enzymes,” Electron. J. Biotechnol., vol. 13, no. 6, Nov. 2010.