Solid state fermentation of fenugreek (Trigonella foenum-graecum): implications on bioactive compounds, mineral content and in vitro bioavailability.

In the present study, solid-state fermentation (SSF) of four fenugreek cultivars viz. HM-57, AFG-2, RMT-1 and RMT-303 were carried out using Aspergillus awamori and its effect on antioxidant properties, phenolic content and bioactive compounds were studied. Macro (Ca, K, and Na) as well as micro (Fe, Zn, and Cu) elements and in vitro bioavailability of the unfermented fenugreek (UFF) and Aspergillus-fermented fenugreek (AFF) samples were assessed with standard methods. On 5th day, total phenolic and condensed tannin contents showed significant (p ≤ 0.05) increase for all cultivars. Further, HPLC analysis confirmed formation of some new bioactive (vanillin, benzoic acid and catechin) compounds. Similarly, extracts from all AFF also showed an increase in the antioxidant potential such as inhibition of DPPH, hydroxyl free radical scavenging, reducing power, and total antioxidant capacity up to 5th day of SSF. Mineral in AFF were found with enhanced values when compared with respective UFF. In vitro bioavailability of Fe, Zn and Ca was also improved during SSF. Results from the present study may be helpful to food industry in developing new health foods and may provide a rational for development of functional ingredient in preparation of novel nutraceuticals. © Association of Food Scientists & Technologists (India) 2020.