Aproveitamento do bagaço de malte como fonte de bioativos utilizando solvente eutético profundo integrado a ultrassom

Abstract

Brewer's Spent Grain (BSG) is a waste generated on a large scale in breweries, and just in Brazil, an average of 280 million tons of this waste are generated annually. BSG has a high nutritional value, and the presence of bioactives denotes that this residue can be reused to generate co-products with industrial applications. The Deep Eutectic Solvents (DES) are solvents with environmental advantages when compared to organic solvents, due to their low toxicity and high recyclability. Four DES were tested in an ultrasound-assisted extraction to recover total phenolic compounds (TPC) from BSG. First, a preliminary screening with DES and their mixtures with 25% water (v/v) was performed in a probe ultrasound to determine which DES is most effective in extracting TPC. Then, a serial extraction was tested using the most effective DES in the first extraction to optimize phenolic extraction. The first extraction series was performed with hexane and ethanol to remove oils and sugars from the sample and favor the extraction of target compounds. The second series of extractions were performed with the DES choline chloride and lactic acid (ChCl:LA) and choline chloride and oxalic acid (ChCl:OA). The highest TPC yield was obtained with the Ethanol → ChCl:OA and Hexane → ChCl:OA systems (0.513 mg GAE L−1 and 0.516 mg GAE L−1 respectively) at 30 ºC. Serial extraction in an ultrasound bath effectively removed oils and sugars from the BSG sample and favored the effectiveness of DES in obtaining total phenolics