白果分离蛋白、清蛋白和球蛋白功能特性的热稳定性

The effect of heating on protein properties extracted from Ginkgo biloba seeds

对白果分离蛋白（GPI）、白果球蛋白（GGP）和白果清蛋白（GAP）的功能特性在不同温度处理下的变化进行了研究。结果表明：不同温度对3种白果蛋白功能特性的影响趋势基本一致,在25-55℃处理后,3种白果蛋白的溶解性、吸水性、起泡能力和泡沫稳定性均得到显著增加,在55℃达到最大,温度再升高则产生不利的影响;吸油性则在55-75℃内呈快速增长,超过75℃,吸油能力反而下降;就乳化容量而言,GAP在55℃、GPI和GGP在65℃升至最高,再升高温度,蛋白质乳化容量下降;加热处理对白果蛋白质乳化稳定性的影响较大,随着温度的升高乳化稳定性均下降。GPI、GGP和GAP 3种蛋白质的变性温度分别为86.17、88.57℃和79.23℃,白果蛋白在高温功能特性下降可能与蛋白质变性密切相关。通过适度加热蛋白质溶液（55-75℃）,可使白果蛋白质的功能特性得到显著的改善。

Functional properties of Ginkgo biloba seed protein isolate, Ginkgo biloba seed globulin protein and Ginkgo biloba seed albumin protein were treated with different temperature. The results showed that solubility, water absorption capacity, foaming capacity and foaming stability of GPI, GAP and GGP were improved at 25 - 55℃ and reached to the best at 55℃ , further increase of temperature results in the opposite effect. The highest oil-absorption capacity was observed at 75℃. As far as emulsifying capacity, the highest value was determined at 55℃ for GAP, 65℃ for GPI and GGP. Heating best influences the emulsion stability. DSC results showed that denaturation tempera- ture of GPI, GGP and GAP was 86.17℃ , 88.57℃ and 79.23℃ respectively. Therefore, heating has negative effects for protein＇s functional properties. The moderate heating treatment （55 - 75℃ ） can improve the functional properties of Ginkgo biloba seed protein.