Solid‐state fermentation of lentil (<scp><i>Lens culinaris</i></scp> L.) with <i>Aspergillus awamori</i>: Effect on phenolic compounds, mineral content, and their bioavailability

Abstract

Abstract Microorganisms have long been used in the production of a variety of foods, alcoholic beverages, additives, and supplements due to their cost effectiveness and environmental advantages. Solid‐state fermentation (SSF) reproduces the natural microbiological process that can be utilized in a controlled way to produce the desired product. In the present study, modulation of phenolic compounds, antioxidant potential, and mineral content during SSF of three lentil cultivars, namely, HM‐1, LL‐931, and Sapna, were explored. The total phenolic content (TPC) for 6th day Aspergillus ‐fermented lentil (AFL) flour increased by 79.2% for cv. HM‐1, 78.8% for cv. LL‐931, and 122.8% for cv. Sapna. High‐performance liquid chromatography (HPLC) results also showed that SSF not only improved the phenolic content of lentil cultivars but also resulted in the formation of some new phenolic compounds (resorcinol and cinnamic acid). The condensed tannin content, DPPH (2,2‐diphenyl‐1‐picrylhydrazyl) inhibition activity, hydroxyl free radical scavenging activity, reducing power activity, and total antioxidant capacity of aqueous ethanolic extracts from all AFLs also increased significantly ( p ≤ 0.05) up to 6th day of fermentation. Mineral content differed significantly ( p ≤ 0.05), with AFL extracts exhibiting higher mineral content than their unfermented counterparts. Among different minerals, Cu content of all AFL extracts was the highest with an increase of 46.4% to 60.0% upon fermentation. All minerals showed a significant ( p ≤ 0.05) increase in their concentrations upon fermentation except for K in which the increase was less than 0.1%. However, in vitro bioavailability of iron and zinc was significantly ( p ≤ 0.05) higher in AFL as compared with their unfermented counterparts, with the highest level being observed on the 6th day of fermentation. Thus, biotransformed lentils could be utilized in the preparation of functional foods and novel nutraceuticals for their health‐promoting properties.