Improvement on storage stability of iron-fortified soybean powder by microencapsulation

Full-fat soybean powder was a more difficult-to-fortify food vehicle than cereal flour and powdered milk products because of a large quantity of unsaturated fatty acids, particularly when iron was necessary to be fortified. Minimizing oxidation of lipids was extremely valuable in the fortified-food industry. However, very limited data were available on the effect of microencapsulation of iron compounds on lipid oxidation in full-fat soybean powder. In our study, ferric pyrophosphate (FP) was microencapsulated by the emulsifying-gelation technique and its effect on the storage stability of Yingyangbao (YYB) was evaluated. The results showed that microencapsulated FP (MFP) was regularly spherical and uniformly distributed. MFP could significantly (P < 0.05) decrease the sensory score of rancid odor for YYB. The formation of lipid oxidation products such as carbonyl compounds, malondialdehyde, pentanal, and hexanal in YYB during the accelerated test was significantly retarded, improving oxidative stability and delaying the sensory deterioration. The E-nose analysis showed that YYB with MFP had significantly (P < 0.05) lower levels of response values on the specific sensors than YYB containing FP with or without ascorbyl palmitate. MFP could significantly (P < 0.05) improve the sensory and oxidative stability of iron-fortified full-fat soybean powder such as YYB.