Fermentation with edible Rhizopus strains as a beneficial alternative method in wheat germ cake processing. (November 2021)

• Record Type: Journal Article
• Authors: Starzyńska-Janiszewska, Anna; Stodolak, Bożena; Mickowska, Barbara; Socha, Robert
• Is Part Of: Journal of cereal science. Volume 102(2021)
• Publication Date: 2021-11
• Subjects: Wheat germ cake -- Solid-state fermentation -- Antioxidant potential -- Protein -- Phenolic acids; Grain -- Periodicals; Cereal products -- Periodicals; Céréales -- Périodiques; Produits céréaliers -- Périodiques; Cereal products; Grain; Periodicals; 664.705
• DOI: 10.1016/j.jcs.2021.103309
• Languages: English
• ISSNs: 0733-5210

Abstract

Abstract: Wheat germ cake (WGC) is a nutritionally valuable by-product of oil production from wheat germ, of broad but not yet fully used potential for food applications. Solid-state fermentation with Rhizopus oligosporus and R. oryzae was tested as a new method of WGC bioprocessing aimed to obtain compact products overgrown with mycelium, characterised by a favourable composition. The best results were obtained after 96-h fermentation. The fermented material contained, on average, 42% more peptides, had 30% higher ABTS˙ + scavenging activity, and 100% higher ˙OH -scavenging activity than the raw substrate. The fermented WGC had, on average, 720 μg/g DM soluble phenolic acids, with a significant share of protocatechuic acid (69%). The fungal activity increased the levels of free protocatechuic acid and p-hydroxybenzoic acid. The fermented WGC was a good source of high-quality protein (28 g/100 g DM) rich in Lys (6.9 g/100 g protein), Phe + Tyr (7.9 g/100g protein) and Leu (7.3 g/100 g protein). The products also contained around 14.5 g/100 g DM of dietary fibre with 60:40 insoluble to soluble fraction ratio. Solid-state fermentation can be considered a new method for increasing the nutritional and bioactive value of WGC, thus extending the possibilities of its application for the food industry. Graphical abstract: Image 1 Highlights: Wheat germ cake is a convenient substrate for Rhizopus strains. Fermentation with Rhizopus enhances the antioxidant activity of wheat germ cake. Protocatechuic acid and p-hydroxybenzoic acid increase after the fermentation. Fermented wheat germ cake is a good source of Lys-rich protein and dietary fibre.