食品科学 ›› 2019, Vol. 40 ›› Issue (15): 142-147.doi: 10.7506/spkx1002-6630-20181014-115

• 食品工程 • 上一篇    下一篇

基于差示扫描量热法研究喷雾干燥鸡蛋全粉热转变温度

赵金红,白 洁,张 清,张小飞,李玉美,袁 诺,刘松南,郭 宏   

  1. 北京食品科学研究院,北京 100068
  • 出版日期:2019-08-15 发布日期:2019-08-26
  • 基金资助:
    “十三五”国家重点研发计划项目(2018YFD0400305);国家自然科学基金青年科学基金项目(31501546)

Thermal Transition Temperatures of Spray-Dried Whole Egg Determined by Differential Scanning Calorimetry

ZHAO Jinhong, BAI Jie, ZHANG Qing, ZHANG Xiaofei, LI Yumei, YUAN Nuo, LIU Songnan, GUO Hong   

  1. Beijing Academy of Food Sciences, Beijing 100068, China
  • Online:2019-08-15 Published:2019-08-26

摘要: 研究含非冻结水(较低水分含量)喷雾干燥鸡蛋全粉与含冻结水(较高水分含量)样品的热转变温度,以及鸡蛋全粉的吸附等温线,为蛋制品干燥或冷冻加工的稳定性提供数据支持。采用差示扫描量热仪检测样品,结果发现含非冻结水样品中有两个吸热峰,分别是卵转铁蛋白和卵白蛋白的变性峰,二者的变性温度(Td)都随湿基水分含量的增大而减小。对于含冻结水的样品,冻结温度(TF)与湿基水分含量之间的关系采用Clausius-Clapeyron方程描述,由冰晶熔融焓值得到非冻结水的湿基水分含量为0.18 g/g,再通过Clausius-Clapeyron方程得到其对应的冻结终点温度(Tm’)为-14.6 ℃。只有当湿基水分含量为0.22 g/g时,才检测到其玻璃化转变温度(-46.3 ℃)。此外,还研究了喷雾干燥鸡蛋全粉的吸附等温线,采用GAB模型进行非线性拟合,结果表明鸡蛋的吸附等温线为II型,其单分子层干基水分含量为0.043 g/g。本研究结果能为蛋制品的最适干燥或冷冻加工条件提供理论依据。

关键词: 热转变, 差示扫描量热法, 吸附等温线, 水分活度, 鸡蛋全粉

Abstract: In order to provide the stability conditions of drying and freezing for whole egg, thermal transition temperatures of spray-dried whole egg powder containing unfreezable water and samples containing freezable water were determined by differential scanning calorimetry (DSC). The adsorption isotherm of whole egg was also established. Spray-dried whole egg powder containing unfrozen water showed two endothermic peaks, which corresponded to the denaturation of ovotransferrin and ovalbumin, respectively. The denaturation temperatures (Td) of ovotransferrin and ovalbumin decreased with the increase of water content. The relationship between freezing point (TF) and water content was modeled using the Clausius-Clapeyron equation. The content of unfreezable water was estimated as 0.18 g/g sample wet basis from the extrapolated enthalpy of ice melting (△Hm), and the corresponding end point of freezing (Tm’) was calculated as ?14.6 ℃ using the Clausius-Clapeyron equation. Only when water content was 0.22 g/g wet basis, was the glass transition temperature detected as ?46.3 ℃. In addition, the water adsorption isotherm of spray-dried whole egg powder was determined at 25 ℃ and the data were fitted to the GAB model. The absorption isotherm was classified as a type II isotherm. The content of monolayer water was found to be 0.043 g/g sample dry basis as the stability criterion based on water activity. These results provide a theoretical rationale for the optimal drying and freezing conditions of whole egg.

Key words: thermal transition, differential scanning calorimetry, sorption isotherms, water activity, whole egg powder

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