不同乳化剂制备乳状液对大豆蛋白凝胶强度影响

摘要

通过静置分层实验和离心分层实验考察了不同乳化剂（卵磷脂、Tween20、大豆蛋白、卵清蛋白和酪蛋白）、pH（3、4、5、6、7、8）、氯化钠浓度（10、50、100、150、200 mmol/L）以及热处理（90℃、30 min）对机械乳化法和超声乳化法制备乳状液稳定性的影响；并考察 pH 7及不同盐浓度（0 mmol/L 和200 mmol/L）条件下不同乳状液对热诱导大豆蛋白凝胶15%（w/v），90℃加热30 min）凝胶强度的影响。结果表明，小分子乳化剂（卵磷脂和 Tween20）制备的乳状液的稳定性优于大分子乳化剂（大豆蛋白、卵清蛋白以及酪蛋白）制备的乳状液；超声法制备的乳状液的稳定性高于机械法制备的乳状液；以超声乳化得到的卵清蛋白乳状液为溶剂制备的大豆蛋白凝胶强度最好；氯化钠的加入可以有效提高凝胶的强度。%Effect of different environmental conditions including emulsifiers(lecithin,Tween20, soybean protein,egg albumin and casein),pH(3、4、5、6、7、8),concentration of sodium chloride(10、50、100、150、200 mmol/L)and heat treatment(90 ℃ ,30 min)on stability of emulsions prepared by mechanical emulsification and phacoemulsification were studied. Then,emulsions were prepared using different emulsifier by mechanical and ultrasonic emulsification. Heat set emulsion–filled whey soy protein gels were prepared at the protein concentration of 15%(w/v),pH 7 and concentration of NaCl(0 mmol/L and 200 mmol/L)by heating at 90 ℃ for 30 min. The experimental results showed that the stability of the small molecule emulsifier lecithin and Tween20 were higher than that of the macromolecular emulsifier soy protein,ovalbumin and casein. Phacoemulsification was better than the mechanical emulsification,and thus the stability of the emulsion prepared by the ultrasound was higher than that by the mechanical emulsification. The strength of soy protein gels of ovalbumin emulsion obtained by phacoemulsification as solvent was maximal. Addition of sodium chloride(200 mmol/L) could effectively improve the strength of the gel.