The Study On Filming Technology Of Edible Soy Protein Isolate

The film-forming characteristics of soy protein isolate (SPI) made in china were systematically studied. The soy protein isolate concentration, filming medium, pH, drying temperature and amount of plasticizers, intensifiers, reducing agents, cross-linking agents were studied through single-factor experiments. The optimal film-forming conditions were obtained through orthogonal experiment design. The main aspects and the results were represented as follows:1 Effects of different soy protein isolate concentration on properties of the film: The film was obtained when soy protein concentration was 3.0%~6.0%. The thickness and the tensile strength of the film correlated positively with their soy protein isolate concentration. The optimal film-forming soy protein isolate concentration was 4.0%.2 Effects of different filming medium on properties of the film: The films were obtained on armor plate, plastic film and glass. The glass is optimal filming medium.3 Effects of different pH on properties of the film: At pH 6.0-10.9, soy protein isolate had better solubility, At pH 8.0~8.9, the film formed had better properties.4 Effects of different drying temperature on properties of the film: The drying temperature was about 50~60#, the drying time was about 17~18h, the film formed had better properties.5 Effects of different plasticizers on properties of the film: Compared with sorbitol, ethylene glycol, 1.2-propanediol, glycerin was better on properties of the film. When glycerin was 1.0-3.0%. The tensile strength of the film correlated negatively with glycerin concentration, the air permeability of the film correlated positively with glycerin concentration. The optimal glycerin concentration was 1.5g /100 ml.6 Effects of different reducing agents on properties of the film: Compared with glucose, Na2SO3 was better on properties of the film. The optimal concentration ofwas 0.05%.7 Effects of different intensifiers on properties of the film: there was no significant better effect on properties of soy protein isolate films, if starch soluble, gelatin and agar were used; The CMC-Na increased the tensile strength significantly, but the color of the films was yellow, the film was semi-transparency.8 Effects of different cross-linking agents on properties of the film: Compared with tannic acid and sodium tripolyphosphate, TG was better on properties of the film. The optimal concentration of TG was 0.15%.9 The optimal film-forming conditions were obtained through orthogonal experiment design. Soy protein isolate was 5.0%, glycerin was 1.5%, Na2SO3was 0.1%, TG was 0.2%.10 The optimal soy protein isolate filming technology: Soy protein isolate 5.0%,glycerin 1.5%, Na2SO30.1%, TGO.2%, The film-forming solution was mixed round20min and heated at 60-70 # about 20min. When temperature of the film-forming solution was 50#, 0.2% TG was put into and heated at 50# about 10min. The film-forming solution was adjusted to pH 8.0~8.9 and kept at room temperature about 6~7h. The film-forming solution was filtrated, Filming on the glass about 9cm2/ml. The drying temperature was about 50-60#, the drying time was 17~18h. The film-formed was kept at RH93% and 30 # for 15min, then, The Film was obtained.