用于阻隔奶油和茶汤快速融合的玉米醇溶蛋白纳米颗粒-柠檬酸交联淀粉复合可食薄膜的制备

Preparation of zein nanoparticles-citric acid cross-linked starch composite edible films for blocking rapid fusion of cream and tea broths

为有效解决奶茶的奶油顶在出品后短时内易与茶汤快速结合的问题,该文以玉米淀粉为成膜基质,柠檬酸为交联剂、玉米醇溶蛋白纳米颗粒(zein nanoparticles,ZNP)为疏水性增强剂,制备一种阻水性能、机械性能良好的ZNP-柠檬酸复合薄膜。通过傅里叶红外光谱、扫描电镜、热重分析和X-射线衍射对复合薄膜结构进行表征,探究薄膜的机械性能、防水性能和光学性能等物理参数。此外,探究了复合薄膜在不同茶汤(茉莉绿茶、四季春、大红袍、锡兰红茶)、不同温度(4、37、45℃)和不同保留时间(0.5、1.0、1.5、2、4、24 h)下的耐水性测试,并验证了复合薄膜在奶茶奶油顶的应用效果。结果表明,淀粉可作为ZNP的优良载体,复合薄膜具有良好的热稳定性、机械性能和阻隔性能。其中,拉伸强度达到4.35 MPa、断裂伸长率达到44.21%,水蒸气透过率为3.07×10^(-12)g·cm/(cm^(2)·s·Pa)。在不同茶底的应用中,复合薄膜的水溶性在大红袍茶汤中最高;在1.5 h时水溶性、溶胀性达到最低值,放置ZNP-柠檬酸淀粉复合薄膜的奶茶在60 min时才开始奶油与茶底进行融合。综上,ZNP-柠檬酸复合薄膜可以应用在奶油顶奶茶中,有效阻隔短时间内奶油塌陷快速与茶汤混合,可作为一种新型的食品专用材料。

To effectively solve the problem that the cream top of milk tea is easy to combine with the tea broth quickly within a short period after production,this paper used corn starch as the film-forming matrix,citric acid as the cross-linking agent,and zein nanoparticles(ZNP)as the hydrophobicity enhancer,to prepare a kind of citric acid-ZNP composite thin film with good water-blocking properties and mechanical properties.The structure of the composite film was characterized by Fourier infrared spectroscopy,scanning electron microscopy,thermogravimetric analysis,and X-ray diffraction to explore the physical parameters of the film,such as mechanical,water resistance,and optical properties.In addition,the water resistance test of the composite films under different tea broths(Jasmine green tea,Four Seasons Spring,Dahongpao,and Ceylon black tea),different temperatures(4℃,37℃,and 45℃),and different retention time(0.5,1.0,1.5,2,4,24 h)was explored,and the application of the composite films in milk tea creamer tops was verified.Results showed that starch could be used as an excellent carrier for ZNP,and the composite films had good thermal stability,mechanical properties,and barrier properties.Among them,the tensile strength reached 4.35 MPa,the elongation at break reached 44.21%,and the water vapor permeability was 3.07×10^(-12)g·cm/(cm^(2)·s·Pa).In the application verification of different tea bases,the water solubility was highest in Dahongpao tea broth,and the composite film reached the lowest value of water solubility and dissolution at 1.5 h.The milk tea with ZNP-citric acid starch composite film was placed at 60 min before the cream started to fuse with the tea base.In summary,the ZNP-citric acid composite film can effectively preserve milk tea with a cream topping,which tends to collapse in a short period of time,thereby preventing the problem of rapid mixing with the tea broth.This film can serve as a novel,food-specific material.