CMC与CMC-Na 改性鸡蛋清蛋白溶胶- 凝胶性质研究

将一定质量分数的离子型多糖羧甲基纤维素(CMC)与羧甲基纤维素钠(CMC-Na)分别溶于蛋清中，冷冻干燥后，将得到的样品置于相对湿度为75% 的环境中干热反应一定时间后，通过质构分析、色度分析、SDS-PAGE、差示扫描量热分析、扫描电子显微镜研究鸡蛋清蛋白与CMC 及CMC-Na 交联改性后性质的变化。结果表明：反应温度60℃、反应时间2d 时，各样品的凝胶强度显著增大，凝胶的微观网络更为均匀致密，蛋清粉中的小分子质量蛋白质减少。证明适度的反应可增强蛋清粉的凝胶强度，但随时间延长，过度反应则会造成分子质量过大、溶解度下降，色泽显著加深。起泡性的分析表明：各反应2d 后样品的起泡性均明显增强，其中以60℃，添加0.25% 的CMC 和CMC-Na 的起泡力最强，分别增大了0.6 倍和0.5 倍，泡沫稳定性亦明显增强。证明在此反应条件下，可获得同时兼顾较高凝胶性和较高起泡性的新型蛋白粉。

Properties Improvement of Egg Albumen by Conjugation with CMC or CMC-Na

Egg white was blended with sodium carboxymethyl cellulose (CMC-Na) or carboxymethyl cellulose (CMC) of certain concentration respectively, and the dry-heated products were obtained at relative humidity (75%) after freeze drying. The products were analyzed on gel strength, color scale, scanning electron microscope observation, SDS-PAGE, and Differential Scanning Calorimetric (DSC) at intervals. The results showed that a significant increase in the gel strength of egg white, more uniform and compact gel network structure and a significant reduction in the content of proteins with small molecular weight were found after 2 days of reaction at 60 ℃. The foaming capacity of egg albumen was found to be enhanced significantly by 2-day-long reaction, but the excessive cross-linking might lead to a large molecular weight, decrease the solubility of egg white powder and darken its color. Adding CMC or CMC-Na at a concentration of 0.25% resulted in the best foaming capacity at 60 ℃, with 0.6-fold and 0.5-fold increases in comparison with a blank sample, respectively and meanwhile, a significant improvement was observed for foam stability. It was proved that a novel egg white powder with both higher gel property and foaming capacity can be obtained under the reaction conditions.