Reports have indicated that lipid peroxidation is a key factor in soybean daddawa deterioration and
Alliums are rich in antioxidants. The present study was carried out to investigate the preservative
abilities of aqueous and ethanolic extracts of Onion (Allium cepa L) on stored soybean daddawa
compared with Sodium Chloride treated samples. Soybean (Glycine max (L). Merr.) seeds fermented
into soybean daddawa was preserved with both extracts (at 3, 5 and 7% concentration) and NaCl (at
the concentrations of 0, 3 and 5%). The samples stored at 30±2°C for up to 14 days were analyzed
for peroxide value (POV), free fatty acid (FFA), pH, titratable acidity (TTA), water absorption
capacity (WAC) and fat absorption capacity (FAC). Type of solvent used in extraction did not have
significant effect on all the storage indices. Extracts of Onion significantly lowered the POV, FFA
and TTA generated in stored soybean daddawa. The pH of stored soybean daddawa samples treated
with the NaCl and aqueous extract was not significantly affected while the ethanolic extract
significantly reduced the pH from 8.26 – 8.34 to 5.72 – 5.89. The tested extracts lowered the WAC
significantly while the FAC of treated soybean daddawa was not significantly affected compared to
those treated with NaCl. Results of this study indicate that both extracts of Onion are more effective
in lowering peroxidation in stored soybean daddawa and thus could be exploited for soybean
daddawa preservation.
