Influence of extrusion on storage quality of dried oat noodles: Lipid degradation and off-flavours

The aim was to investigate whether extrusion could improve the storage stability of dried oat noodles by inhibit lipid-degrading enzyme activity and the degradation of lipids. Thus, noodles were made from extrusion-treated oat under two treatment conditions and subjected to 12-week storage. Extrusion completely inactivated lipase and peroxidase in oat flour, while lipoxygenase activity persisted at a low level. Processing of dried oat noodles also influenced enzyme activity dramatically. For instance, the most significant impact was observed for lipase activity, which dropped to ca. 11 U.min(-1).g(-1) in the freshly prepared noodles made from non-heat-treated oat flour. Lipid hydrolysis was greatly controlled in extrusion-treated noodles as fatty acid values did not increase during storage. The total lipids decreased more in the extrusion-treated groups than in the control sample, which may indicate the promotion of extrusion in non-enzymatic reactions, as the initial values of volatile compounds were much higher. Interestingly, the occurrence of non-enzymatic lipid oxidation should not be severe during storage, as the reduction of tocols and the accumulation of volatile compounds were only moderate in extrusion-treated oat noodles. In conclusion, extrusion could be an effective method for enhancing the storage stability of dried oat noodles.

Automated summary

Extrusion treatment effectively controlled lipid hydrolysis and promoted non-enzymatic reactions in oat noodles, leading to enhanced storage stability and reduced lipid degradation during storage.