Improvement of the Gel Properties of Salted Egg White and Its Application in the Processing of Dried Salted-Egg-White Curd

Salted egg white is rich in protein and can be used as material for the processing of dried curd. However, its ability to form a gel is weak, which may lead to a low hardness and poor quality in the dried curd production. Therefore, the unimproved salted egg white is not suitable for dried curd processing by a direct heating method. In the present paper, based on the analysis of the gel properties of salted egg white, the texture and quality of dried salted-egg-white curd were significantly improved through the optimization of process formulation and parameters, and a heat-induced solidification process technology of dried curd with brining procedure not included was successfully established, meanwhile a comprehensive characterization of the texture, sensory quality, water content, water holding capacity and microstructure of the products processed under the optimized conditions was also carried out. The results showed that the heating temperature and time had significant effects on the appearance, hardness, springiness and cohesiveness of dried curd, and 80 ℃ and 2.5 h were the preferred heating temperature and time. The addition of fresh whole egg liquid and egg white powder significantly improved the gel properties and texture of dried curd, while the appropriate additions of soybean flour, salted egg yolk and brine solution markedly ameliorated the flavor and texture. The optimized formulation obtained by mix design experiment was as follows: salted egg white 61.49%, fresh whole egg liquid 30.75%, egg white powder 5.00%, soybean flour 2.00%, salted egg yolk 0.76% and brine solution 2.0%. The dried curd produced under the optimized parameters showed a high sensory score of 96.80, a strong water holding capacity of 90.84%, a dense and fine texture and bright color, of which the hardness, springiness and cohesiveness were 2711.30 g, 0.85 and 0.68, respectively. In summary, the gelation capacity of salted egg white was significantly improved through formulation optimization, and the established process technology of dried salted-egg-white curd was practicable, under which the products showed an outstanding quality.