| Flaxseed protein isolate (FPI) was prepared from dehulled flaxseeds in aqueous medium. The effects of heat treatment on the composition of FPI subunits, types and contents of volatile substances, and the functional properties of FPI were studied. The results showed that the aggregation and dissociation of protein subunits increased with the extension of heat treatment time. When heated at 95 ℃ for 10 min, the subunits of FPI changed greatly, and the subunits with relative molecular weights of 35-50 kDa could be rapidly dissociated. The volatile substances in FPI increased from 32 types to 42 types after heat treatment at 95 ℃ for 10 min, and the main types were still aldehydes, alcohols and ketones, but the flavor substances with leaf and grass flavor decreased, while the flavor substances with oil, burnt and roasted flavor increased. After heat treatment, the solubility of FPI at pH 7.0 decreased from 30% to 25%, while that of SPI decreased from 95% to 35%. In addition, the emulsifying activity of FPI increased from 17.43 m2/g to 26.03 m2/g, the emulsion stability decreased from 43.28 min to 37.45 min, but water holding capacity and oil holding capacity had no significant change. |
