Effect of Superheated Steam Treatment and Extrusion on Lipid Stability of Black Soybean Noodles During Storage

This study investigated the effect of superheated steam treatment (SST) and extrusion treatment (ET) on the changes of lipids in black soybean noodles (BSN) during storage. Degradation of lipids and formation of volatile compounds were closely related to the endogenous lipid-degrading enzyme activity. Both SST and ET could effectively inactivate lipase, lipoxygenase and peroxidase activity in black soybeans, and thus in the BSN. The content of polyunsaturated fatty acids decreased by 43.6% in non-heat-treated BSN during 7-week storage, whereas the reduction was only 23.0% and 20.7% in SST-190 degrees C and ET-130 degrees C groups, respectively. The degradation of tocopherols and tocotrienols, and formation of volatile compounds in the BSN was greatly inhibited during storage by the two heat processes, and ET seems to be more effective. In conclusion, both SST and ET were able to increase the lipid stability of BSN by inhibit the activity of lipid-degrading enzymes. This study could also provide more knowledge that assists to develop high quality of black soybean food products.