| The effects of spray drying and vacuum freeze drying on the functional properties of protein isolate from cold-pressed flaxseed cake were researched. The results showed that the solubility, water holding capacity, oil absorption, emulsifying activity, emulsion stability and foam stability of the vacuum freeze dried flaxseed protein isolate were higher than those of the spray dried flaxseed protein isolate, while the latter had higher foaming capacity than the former. At the neutral pH, the water holding capacities of proteins prepared by vacuum freeze drying and spray drying were 6.75 g/g and 5.74 g/g, respectively. The obtained flaxseed protein isolate also showed good oil absorption, especially for vacuum freeze dried protein. At 30 ?℃, oil absorption of the spray dried protein was 1.91 g/g, while the vacuum freeze dried protein was 3.09 times as high as spray dried protein. The curves of water holding capacity, emulsifying activity and emulsion stability of flaxseed protein isolate as the pH changed were similar to that of solubility, all of which showed the lowest value at pH 4. |
