Characterization of industrial açaí pulp residues and valorization by microwave-assisted extraction

Abstract

Açaí (Euterpe oleracea Mart.) is a berry found in Amazon Rainforest. Due to its increasing commercial value, the cultivation of this fruit in northern Brazil is growing quickly, and with it the increasing production of waste by this industry also poses a growing problem. This study presents a characterization of all residual fractions of the industrial processing of açaí and assesses its potential as biomass and phytochemicals source, determining the content of lipids, extractives, sugars, ashes, proteins, and the phytochemical composition of each residual fraction. It also studies the extraction of these compounds by intensified microwave-assisted techniques (ambient-pressure microwave extraction and pressurized microwave extraction at 1.5 bar and 3 bar). The oil content represents 43.1 % of the dry pulp weight, in which fatty acids such as oleic acid (58.5 %), linoleic acid (22.3 %), palmitic acid (11.4 %) and stearic acid (4.1 %) were identified. The pulp and seeds showed potential as antioxidant agent with ORAC (oxygen radical absorbance capacity) values of 89,760 and 65,263 μmol TE/100 gDM. Microwave pre-treatments allowed to increase the polyphenol contents and the antioxidant activities of extracts obtained from the pulp and seed residues, yielding products of interest for the cosmetic or food industry.