Fungistatis activity of flaxseed in potato dextrose agar and a fresh noodle system.

Key Findings:

Flaxseed appears to have properties that would allow its use as a natural preservative in food products. In previous work by the authors, it was observed that mold spoilage in refrigerated fresh pasta was inhibited by ground flaxseed. The antifungal activity of flaxseed was assessed in an agar model and a noodle system. The effect of different source of cultivar sources was evaluated. No correlation was found between the antifungal activity and flaxseed cultivar. Flaxseed concentration at 15% inhibited the growth of the molds to a similar degree as a 0.2% propionic acid. The research exhibits natural fungistatic properties of flaxseed. The current study indicates that flaxseed could be used to inhibit molds in foods that do not undergo heat treatments prior to packaging and storage.

ABSTRACT:

Although numerous researchers have studied flaxseed as a food ingredient for its health benefits, flaxseed (Linum usitatissimum) has never been considered as a food preservative. The objective of this study was to investigate the effect of flaxseed flour (FF) concentration (0, 6, 9, 12, and 15% wt/wt), cultivar (‘Omega’ and brown) and source (four seed companies located in Minnesota and North Dakota) on flaxseed fungistatic activity. Fungal radial growth was used to assess the fungistatic activity of FF in both potato dextrose agar (PDA) medium and a fresh noodle system. Strains of Penicillium chrysogenum, Aspergillus flavus, Fusarium graminearum, and a Penicillium sp. isolated from molded noodles were used as the test microorganisms. Results showed that growth of F. graminearum was completely inhibited at all FF concentrations in PDA, and the inhibition of the other three test microorganisms increased with increasing FF concentrations. In the model noodle system, FF concentration at 9% or higher significantly reduced the mold count of fresh noodle during storage. In the inoculated noodle system, 6% FF addition was sufficient to significantly inhibit the growth of F. graminearum and A. flavus, whereas 9% FF concentrations showed fungistatic activity against P. chrysogenum and the Penicillium sp. isolate. Differences in the degree of mold inhibition were found among FFs obtained from different sources and cultivars. Results suggested that flaxseed possesses fungistatic activity and could be used as a multifunctional food ingredient. (Author’s abstract)