Flours from fermented lentil and quinoa grains as ingredients with new techno-functional properties

The need to provide novel, nutritious plant-based products requires seeking high-value, sustainable protein sources, like quinoa and lentils, having an increased digestibility and lacking antinutrients. Fungal fermentation has evidenced enhanced nutritional value of flours obtained from these grains. However, research into techno-functional properties, essential to the new product development, is lacking. This study investigated the techno-functional properties of flours made from lentil and quinoa after fermenting them with Pleurotus ostreatus and subjecting them to two drying techniques (lyophilisation and hot air drying). In both cases, the fermentation led to noteworthy improvements in swelling and water holding capacity, especially in those lyophilised than those dried. In contrast, the emulsifying, foaming, thickening, and gelling capacities decreased significantly. The loss of abilities was more severe for dried grains than for lyophilized ones. The thermomechanical analysis of the fermented flours showed lower thickening and gelling potential compared to untreated flours. Microscopy images revealed that the state and structure of starch granules were affected by both fermentation and drying processes. Starch granules in lentils were partly pre-gelatinised and trapped in the cotyledon cell, resulting in limited thickening and gelling abilities. In contrast, in quinoa, starch underwent pre-gelatinisation and retrogradation during the fermentation process, promoting the production of resistant starch and increasing fibre content. This study presents the potential of treated flours as ingredients possessing unique attributes compared to protein and fibre-rich conventional products.

This research was funded by the Spanish government MCIN/AEI/10.13039/501100011033, grant numbers PID2019- 107723RB-C21 and grant numbers PID2019- 107723RB-C22, and Ia ValSe-Food Ref. 119RT0567 from CYTED Program. The authors also thank to the Spanish government MCIN/AEI to the Center of Excellence Accreditation Severo Ochoa (CEX2021-001189-S/ MCIN/AEI / 10.13039/501100011033).

With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX 2021-001189-S)

Peer reviewed