Department of Agri-food Industry, Food and Nutrition (LAN), Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), Piracicaba, SP, Brazil.
Department of Agri-food Industry, Food and Nutrition (LAN), Luiz de Queiroz College of Agriculture (ESALQ), University of São Paulo (USP), Piracicaba, SP, Brazil.
Food Res Int. 2017 Oct;100(Pt 1):468-476. doi: 10.1016/j.foodres.2017.07.045. Epub 2017 Jul 20.
This work aimed to describe the acidification process of two specific model foods using the ultrasound technology, as well as to evaluate the changes on its viscoelasticity properties. For that, two types of model food were used, with similar composition but different structures: natural melon cylinders and restructured melon-agar cylinders. The acidification process was performed using a citric acid solution (0.2% w/w) assisted with and without ultrasound (40W/L of volumetric power and 20kHz of frequency) at constant temperature (25°C). In addition, the stress relaxation analysis was performed on the cylinders in order to evaluate the changes on the viscoelastic properties. As a result, both ultrasound processing and the different structural conformation of the model foods affected the acidification kinetics, being improved by ultrasound. Further, the acidification process with and without ultrasound affected the mechanical properties of both products, reducing their elasticity. The relaxation data could be described by a Maxwell model with two bodies and a residual spring, providing a possible explanation of the association between the mechanical model parameters and the microstructural conformation of both studied cases.
本工作旨在使用超声技术描述两种特定模型食品的酸化过程，并评估其黏弹性性质的变化。为此，使用了两种具有相似组成但结构不同的模型食品：天然瓜圆柱和重组瓜-琼脂圆柱。酸化过程使用柠檬酸溶液（0.2%w/w）进行，在恒定温度（25°C）下，有和没有超声（40W/L 的体积功率和 20kHz 的频率）辅助。此外，对圆柱进行了应力松弛分析，以评估黏弹性性质的变化。结果表明，超声处理和模型食品的不同结构构象都影响了酸化动力学，超声处理可以改善酸化动力学。此外，有和没有超声的酸化过程都影响了两种产品的机械性能，降低了它们的弹性。松弛数据可以用一个具有两个主体和一个残余弹簧的 Maxwell 模型来描述，为机械模型参数与所研究的两种情况的微观结构构象之间的关联提供了一个可能的解释。
