Protein functionality of concentrates prepared from yellowfin tuna (Thunnus albacares) roe by cook-dried process

Three kinds of roe protein concentrates (RPCs: boil-dried concentrate, BDC; steam-dried concentrate, SDC; freeze-dried concentrate, FDC) were prepared from yellowfin tuna to produce value added products for food applications. The buffer capacities of the RPCs were higher under alkaline than under acidic conditions. The water holding capacities of the RPCs were in range 4.5-4.7 g/g protein at pH 6.0. The protein solubility of the FDC (14.2%) was higher than those of the BDC (5.4%) and SDC (5.5%) at pH 6.0. The foaming capacity of the FDC (156.8%) was higher than those of the BDC (109.7%) and SDC (109.4%); the FDC foam was stable for 60 min. The oil-in-water emulsifying activity index of the FDC (12.2 m(2)/g protein) exceeded those of the BDC and SDC (2.2 m(2)/g protein). Protein concentrates from yellowfin tuna roe may be useful as a potential protein source and as a high-value food ingredient.