Evaluation of stability and quality of bioproducts derived from solid-state fermentation of wheat bran using Mortierella alpina.

Solid-state fermentation is an efficient and economically viable biotechnological approach for converting low-cost substrates into high-value fermented bioproducts. This study used the filamentous fungus Mortierella alpina to directly enrich wheat bran substrate with a myriad of polyunsaturated fatty acids (PUFAs) and natural antioxidants, including phenolic acids and flavonoids. These PUFAs, with long carbon chains containing two or more unsaturated double bonds, are highly susceptible to oxidation, which can deteriorate the quality of the fermented bioproduct. Consequently, biochemical alterations during three distinct storage conditions were evaluated. Over 2 months of storage, the total fatty acid content decreased slightly. The inert nitrogen atmosphere showed a strong ability to preserve PUFAs, as only an 8% reduction in total fatty acid content was observed. Even the most valuable C20-PUFAs remained abundant after 2 months of storage. During the storage period, other organic compounds, specifically phenolic acids, accumulated, enhancing the thermo-oxidative stability of the fermented bioproducts, which were already enriched with various PUFAs. These findings were also confirmed by conducting differential scanning calorimetry. PRACTICAL APPLICATION: This research article detailed the assessment of the stability and quality of fermented products produced through solid-state fermentation using the filamentous fungus Mortierella alpina. The fermented product is enriched with microbial oils and additional bioactive compounds, which enhance its thermo-oxidative stability, thus increasing its application in the feed and food industries.