食品科学 ›› 2022, Vol. 43 ›› Issue (18): 16-23.doi: 10.7506/spkx1002-6630-20211108-088

• 食品化学 • 上一篇    

玉米后熟期间醇溶蛋白结构和理化特性

李琦,葛思彤,张士禹,王天池,郑明珠,吴玉柱,赵城彬,刘景圣   

  1. (吉林农业大学食品科学与工程学院,小麦和玉米深加工国家工程研究中心,吉林 长春 130118)
  • 发布日期:2022-09-28
  • 基金资助:
    国家自然科学基金面上项目(32072217);吉林省教育厅科学技术研究项目(JJKH20220348KJ); 国家现代农业产业技术体系专项(CARS-02)

Structure and Physicochemical Properties of Zein during Postharvest Ripening of Corn

LI Qi, GE Sitong, ZHANG Shiyu, WANG Tianchi, ZHENG Mingzhu, WU Yuzhu, ZHAO Chengbin, LIU Jingsheng   

  1. (National Engineering Research Center for Wheat and Corn Deep Processing, College of Food Science and Engineering, Jilin Agricultural University, Changchun 130118, China)
  • Published:2022-09-28

摘要: 将新采收的玉米在温度15 ℃及25 ℃、相对湿度55%条件下进行恒温恒湿贮藏,研究玉米后熟期间玉米醇溶蛋白结构特征及理化特性,并分析二者之间的构效关系。结果发现,玉米在15 ℃及25 ℃后熟56 d期间内,玉米醇溶蛋白的游离巯基含量降低,二硫键含量升高,表面疏水性降低,Zeta电位的绝对值增加,粒径和分散指数降低。玉米后熟期间玉米醇溶蛋白中氢键缔合下降,更多有序的β-折叠转化至无序结构,且后熟作用导致玉米醇溶蛋白热稳定性和α-玉米醇溶蛋白亚基的分子质量降低。此外,玉米后熟显著改变了蛋白的理化特性,在15 ℃后熟42 d和25 ℃后熟28 d,玉米醇溶蛋白的溶解性和持水性均达到最大,在2 个温度下后熟14 d时乳化活性和起泡性均显著增加,而后熟作用导致持油性下降。玉米后熟过程中玉米醇溶蛋白理化特性的改善可能与蛋白质聚集程度降低及其柔性结构相关。结果表明,适当的玉米后熟能够修饰玉米醇溶蛋白结构,进而改善其理化特性。

关键词: 玉米;后熟;玉米醇溶蛋白;结构;理化特性

Abstract: Newly harvested corn was stored under constant temperature (15 or 25 ℃) and relative humidity (55%). The structure and physicochemical properties of zein during postharvest ripening of corn were studied, and their relationship was analyzed. During the 56-day postharvest ripening period at 15 and 25 ℃, the free sulfhydryl content, surface hydrophobicity, particle size and polydispersity index (PDI) of zein decreased, while the disulfide bond content and absolute value of zeta-potential increased. The hydrogen bond association decreased, and more ordered β-sheets were transformed into a disordered structure, and the thermal stability and the molecular mass of α-zein subunit decreased. In addition, during postharvest ripening of corn the physicochemical properties of zein significantly changed. The solubility and water-holding capacity of zein reached their maximum on the 42th day at 15 ℃ and on the 28th day at 25 ℃, and the emulsifying and foaming capacity increased significantly after postharvest ripening for 14 days at both temperatures. However, the oil-holding capacity decreased. The improvement in physicochemical properties of zein during postharvest ripening of corn may be related to the reduction in protein aggregation and its flexible structure. These results showed that proper postharvest ripening of corn could modify the structure of zein and consequently improve its physicochemical properties.

Key words: corn; postharvest ripening; zein; structure; physicochemical properties

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