Nutritional and antioxidant changes in lentil and quinoa induced by fungal solid-state fermentation with Pleurotus ostreatus

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Abstract

Abstract Solid-state fermentation (SSF) could be considered a suitable bioprocess to produce protein-vegetal ingredients with increased nutritional and functional value. This study aimed at assessing changes in phenols and antinutrients contents, along with biomass and protein production, resulting from the metabolic activity of Pleurotus Ostreatus, and edible fungus, in lentil and quinoa during 14 days of solid-state fermentation. The impact of particle size on these parameters was also assessed as the process was conducting in both seeds and flours. According to the obtained results, fungus biomass raised along fermentation and reached 30.0 ± 1.4 mg/ g dry basis and 32 ± 3 mg/ g dry basis in lentil grain and flour, and 52.01 ± 1.08 mg/ g dry basis and 45 ± 2 mg/ g dry basis in quinoa seed and flour after 14 days of SSF. Total protein content also increased about 20-25% along fermentation, excepting in lentil flour. However, soluble protein fraction remained constant. Regarding phytic acid, a positive impact of SSF was found with a progressive decreased, being higher in flours (90% of reduction) than in seeds. With respect to antioxidants properties, autoclaving of the substrates promoted the release of polyphenols together with an antioxidant activity (ABTS, DPPH and FRAP) in all substates. These parameters, however, drastically decreased as along as fermentation progressed. In conclusion, these results provide scientific knowledge for producing a based-lentil or quinoa fermented ingredients with higher protein content and low antinutrients content than their counterparts.