Fermentação da torta de linhaça como estratégia para o enriquecimento nutricional e potencialização de atividade antioxidante

Abstract

The extraction of flax seed oil (Linum usitatissimun) has attracted interest due to the significant amounts of bioactive compounds present in flaxseed. However, after obtaining the oil, a large amount of waste is generated, obtaining as a byproduct the "flaxseed cake". This product in most cases is discarded despite its great nutritional potential. From the biotransformation processes of the raw material, the present work aims to improve the availability of bioactive potential compounds in flaxseed cake. Flaxseed cake, obtained from an industry located in southern Brazil, presented a considerable amount of lipids (11.97%) and proteins (24.33%). Different solvents (PA methanol, PA ethanol, water, 75% ethanol) and temperatures (30, 50 and 70 degrees centigrade) were tested during the phenolic extraction process of assisted ultrasound at a fixed time of 15 minutes. Using water as solvent and at higher temperatures the best results were obtained, obtaining around 2.00 mg EAG g − ¹ on dry basis and an antioxidant activity of 13 μmol compared to TEAC g − ¹. The biotransformation of flaxseed cake was performed by a solid-state fermentation process using Rhizopus oligosporus NRL2710. After 288 hours of cultivation, an increase of 10% in the phenolic compound content was observed in flaxseed cake, presenting an aqueous extract with 19.2 mg of GAE g − ¹ and an antioxidant activity of 81,1 μmol compared to TEAC g − ¹.