罗非鱼-大豆共沉淀蛋白乳液稳定二十二碳六烯酸藻油的研究

Tilapia-soy co-precipitation protein stabilized docosahexenoic acid algae oil emulsion

为探究共沉淀蛋白乳液稳定二十二碳六烯酸(docosahexenoic acid,DHA)藻油的可行性,该研究以罗非鱼分离蛋白(tilapia protein isolate,TPI)、3种罗非鱼-大豆共沉淀蛋白(tilapia-soy protein co-precipitates,TSPC_(2∶1)、TSPC_(1∶1)和TSPC_(1∶2))和大豆分离蛋白(soy protein isolate,SPI)为乳化剂,高压均质制备TPI、TSPC和SPI-DHA藻油乳液,比较5种乳液的物理稳定性和氧化稳定性。结果表明,与TPI乳液比较,随着原料中大豆比例的增加,TSPC-DHA藻油乳液的平均粒径和乳析指数减小(P<0.05),Zeta电位绝对值增大(P<0.05),乳液的物理稳定性增强。与SPI乳液比较,贮藏过程中TSPC-DHA藻油乳液的过氧化值和硫代巴比妥酸反应物值明显较小(P<0.05),乳液的氧化稳定性明显改善。TSPC_(1∶1)和TSPC_(1∶2)乳液在4℃贮藏28 d无明显分层,氧化产物含量接近TPI乳液,乳液稳定性较好。初步分析,共沉淀蛋白中的大豆蛋白组分能更好地覆盖油水界面,提高了乳液贮藏的物理稳定性,而鱼蛋白组分能够减缓油脂的氧化速率,提高了乳液贮藏的氧化稳定性。TSPC乳液具有优于TPI乳液的物理稳定性和优于SPI乳液的氧化稳定性,可用作良好的乳化剂稳定DHA藻油。该研究结果可为共沉淀蛋白功能乳液的开发提供参考。

To explore the feasibility of stabilizing docosahexenoic acid(DHA)algal oil by co-precipitation protein emulsion,tilapia protein isolate(TPI),three tilapia-soy protein co-precipitation(TSPC_(2∶1),TSPC_(1∶1),and TSPC_(1∶2)),and soybean protein isolate(SPI)were used as the emulsifiers,and the TPI,TSPC,andsoy protein isolate-DHA(SPI-DHA)algae oil emulsions were prepared by high-pressure homogenization.The physical stability and oxidation stability of the five emulsions were compared.Results showed that compared with TPI emulsion,the average particle size and creaming index of TSPC-DHA algae oil emulsion decreased(P<0.05),and the absolute value of Zeta potential increased(P<0.05),and the physical stability of the emulsion increased with the increase of the proportion of soybeans in the raw material.Compared with SPI emulsion,the peroxide value and TBARS value of TSPC-DHA algae oil emulsion during storage were significantly lower(P<0.05),and the oxidation stability of the emulsion was significantly improved.TSPC_(1∶1)and TSPC_(1∶2)emulsions had no obvious separation at 4℃for 28 d without the content of oxidation products being close to the TPI emulsion,and the emulsion stability was good.Preliminary analysis showed that the soy protein component of the co-precipitated protein could better cover the oil-water interface and improve the physical stability of emulsion during storage,while the fish protein component could slow down the oxidation rate of oil and improve the oxidation stability of emulsion during storage.Therefore,TSPC emulsion had better physical stability than TPI emulsion and better oxidation stability than SPI emulsion,which could be used as a good emulsifier to stabilize DHA algae oil.These results provide a reference for the development of co-precipitated protein functional emulsions.