Enhancement of Nutritional Value of Cereals with γ-Linolenic Acid by Fungal Solid-State Fermentations
Milan Čertík*, Lucia Sláviková, Silvia Masrnová and Ján Šajbidor
Department of Biochemical Technology, Faculty of Chemical and Food Technology, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovak Republic
Article history:
Received January 21, 2005
Accepted July 8, 2005
Key words:
cereals, fungi, γ-linolenic acid, solid state fermentation
Summary:
The capability of lower filamentous fungi to utilize and to enrich cereals with γ-linolenic acid (GLA) by solid state fermentation was investigated. Thamnidium elegans was selected as a production strain and a variety of cereal materials were tested with the emphasis on achieving cereal-based bioproducts with high GLA content. It was found that dry substrate/water mass ratio of 1:1.5 was optimal for GLA formation. Also, the addition of spent malt grains (SMG) as an internal support to substrates at a mass ratio of 1:3 increased lipid accumulation in bioproducts up to 1.5-fold and GLA yield in bioproduct up to 4-fold. The study revealed that linoleic acid in substrates mixed with SMG was more efficiently transformed to GLA than without SMG. Similarly, an increase in the concentration of linoleic acid in fatty acids of substrates mixed with SMG was accompanied by direct GLA accumulation in bioproduct. Fungal growth on the mixture of wheat bran and SMG (3:1) and on the mixture of spelt wheat flakes and SMG (3:1) resulted in maximal level of GLA in fatty acids (13–14 %). However, the highest yield of GLA (7.2 g/kg bioproduct) was reached when the mixture of spelt wheat flakes and SMG at a ratio of 3:1 was used as substrate.
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