冲泡茶汤对食品风味品质和蛋白质结构及升糖指数的影响研究  

Effects of Brewed Tea on Flavor Quality,Protein Structure and Glycemic Index of Food Product

作　　者：李望舒 沈燕波 吴焕 谢昕雅 袁嘉仪 郭青 徐晴晴 蔡淑娴[1] LI Wang-shu;SHEN Yan-bo;WU Huan;XIE Xin-ya;YUAN Jia-yi;GUO Qing;XU Qing-qing;CAI Shu-xian(Department of Tea Science,College of Horticulture,Hunan Agricultural University/Key Laboratory of Tea Science,Ministry of Education,Hunan Agricultural University/National Research Center for the Utilization of Plant Functional Components,Changsha,Hunan 410128,China)

机构地区：[1]湖南农业大学园艺学院茶学系/国家植物功能成分利用工程技术研究中心/湖南农业大学茶学教育部重点实验室,湖南长沙410128

出　　处：《茶叶学报》2023年第3期13-22,共10页Acta Tea Sinica

基　　金：广西六堡茶“八新双增”关键技术研究与产业化示范(AA20302018);国家重点研发计划(2018YFC1604405);国家自然科学基金面上项目(31471590)。

摘　　要：【目的】茶元素食品既具有独特的风味品质,还具有显著的健康功效。利用茶汤制备鸡蛋羹和米饭,探究茶元素食品的风味品质、蛋白质结构与升糖指数,为茶元素食品开发提供理论依据。【方法】采用冲泡法制备绿茶和红茶茶汤,再用茶汤替代纯水制备鸡蛋羹和米饭,分别以纯水制备的鸡蛋羹和米饭为对照,采用感官审评、扫描电子显微镜(SEM)和傅里叶红外光谱(FTIR)等方法对茶鸡蛋羹和茶米饭的风味品质和蛋白质结构进行分析,并采用体外消化模拟试验测定茶米饭的升糖指数。【结果】与对照相比,茶汤制备的鸡蛋羹口感鲜醇细腻,香气宜人,其中红茶鸡蛋羹口感最为嫩滑;SEM和FTIR结果显示,红茶鸡蛋羹颗粒粒径最小,表面更为均匀;绿茶和红茶鸡蛋羹的蛋白质酰胺Ⅰ带吸收峰显著增加,蛋白质二级结构中无规则卷曲相对含量升高,α-螺旋的相对含量降低,且红茶鸡蛋羹的无规则卷曲上升和α-螺旋下降的趋势高于绿茶鸡蛋羹。绿茶米饭口感清甜有嚼劲,且具有绿茶的清香和栗香香气;SEM和FTIR结果显示,与对照相比,绿茶米饭横切面的微观结构中孔洞数量减少,表面较平滑紧实;绿茶米饭在1022~1000 cm^(-1)峰位置向低波段偏移,表明绿茶可提高淀粉的有序性,从而有效降低米饭的消化率;绿茶和红茶米饭在1080 cm^(-1)处的波峰向低波段移动,并且带宽更宽,表明其淀粉中形成了更多的氢键。绿茶和红茶茶汤均能显著降低米饭血糖生成指数(GI)。【结论】红茶在提高鸡蛋羹风味品质和减少蛋白质过敏结构的形成方面具有显著优势。绿茶和红茶均可用于制备较低血糖指数米饭,且绿茶米饭风味品质佳。【Objective】Effects of using brewed tea to replace plain water in preparing custard and in cooking rice to improve the sensory and healthful qualities of the products were investigated.【Method】Brewed green and black teas were used as an ingredient in making custards and in cooking rice.A sensory panel was employed to evaluate the eating quality of the custard and rice.Scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FTIR)were applied to examine the changes on the microstructure and egg protein of the custard and the molecular structure of the rice protein.An in vitro digestion test was conducted to determine the glycemic index(GI)of the prepared rice that might be affected by the altered protein molecular structure.【Result】Both tea-containing custards and cooked rice tasted fresh and mellow with a pleasant aroma.Black tea made the mouthfeel of the products more tender and smoother than control,which used plain water as an ingredient or for the cooking.Green tea accentuated the sweetness taste with a hint of the typical green tea aroma and chestnut flavor note and increased the elastic texture of the custard and rice.The SEM and FTIR images on the products showed that(1)the particles of the black tea-containing custard were smaller than the green tea-containing counterpart or control,and the surface appeared smooth and uniform;(2)the absorption peaks of protein amide I band of the custards containing either green or black tea were significantly higher than that of control,while the relative content of random coils in protein secondary structure increased and that ofα-helix decreased over control;(3)the increase on random coils and decrease onα-helix in the egg protein of the black tea custard were greater than those of the green tea counterpart;(4)the cross-sectional microstructure of green tea custard showed fewer holes with a surface smoother and more compact than that of control;(5)the peak position of 1022-1000 cm^(-1) of the rice cooked with the brewed green tea shifte

关 键 词：红茶 绿茶 鸡蛋羹 米饭 风味品质 蛋白质过敏结构 血糖生成指数 茶元素食品 

分 类 号：S571.1[农业科学—茶叶生产加工]