Evangelista Rodrigo Rodrigues, Sanches Marcio Augusto Ribeiro, de Castilhos Maurício Bonatto Machado, Cantú-Lozano Denis, Telis-Romero Javier
Food Engineering and Technology Department, State University of São Paulo, São José do Rio Preto, São Paulo 15054-000, Brazil.
Food Engineering and Technology Department, State University of São Paulo, São José do Rio Preto, São Paulo 15054-000, Brazil.
Food Res Int. 2020 Nov;137:109431. doi: 10.1016/j.foodres.2020.109431. Epub 2020 Jun 12.
The rheological behavior and thermophysical properties (density, specific heat, and thermal conductivity) were experimentally determined as function of temperature (1-66 °C) and solid soluble content (13.6-45.0°Brix) for Malbec grape juice aiming at designing the unit operations involved in beverage industries. Mathematical modeling was performed to provide valuable information about the rheological behavior and thermophysical properties of Malbec grape juice at different concentrations and temperatures. The Ostwald-de Waele model fitted the concentrates rheological behavior with high accuracy. The consistency coefficients were significantly reduced by the temperature increase, following an Arrhenius relationship with activation energy ranging from 11.02 kJ/mol (45.0 °Brix) to 11.54 kJ/mol (21.0 °Brix). In contrast, they were increased by the higher concentration levels, ranging from 0.2044 Pa.s (13.6 °Brix, 6 °C) to 20.9451 Pa.s (45.0 °Brix, 1 °C). The flow behavior index was not influenced by temperature; however, it was strictly related to the concentration, assuming shear-thinning behavior (0.96 < n < 0.54), regardless of the solid soluble contents. Density, specific heat, and thermal conductivity were significantly correlated with both the temperature and concentration parameters by second-order polynomial models. The obtained results can be suitable for the potential use of Malbec juice concentrate as a chaptalization agent in winemaking and grape juice production.
为了设计饮料工业中涉及的单元操作，对马尔贝克葡萄汁在温度（1 - 66°C）和固溶物含量（13.6 - 45.0°Brix）变化时的流变行为和热物理性质（密度、比热容和热导率）进行了实验测定。通过数学建模来提供有关不同浓度和温度下马尔贝克葡萄汁流变行为和热物理性质的有价值信息。奥斯特瓦尔德 - 德瓦勒模型能够高精度地拟合浓缩汁的流变行为。随着温度升高，稠度系数显著降低，遵循阿累尼乌斯关系，活化能范围为11.02 kJ/mol（45.0°Brix）至11.54 kJ/mol（21.0°Brix）。相反，随着浓度升高，稠度系数增大，范围从0.2044 Pa·s（13.6°Brix，6°C）至20.9451 Pa·s（45.0°Brix，1°C）。流动行为指数不受温度影响；然而，它与浓度密切相关，呈现剪切变稀行为（0.96 < n < 0.54），与固溶物含量无关。密度、比热容和热导率通过二阶多项式模型与温度和浓度参数显著相关。所得结果可适用于马尔贝克浓缩汁在酿酒和葡萄汁生产中作为增糖剂的潜在应用。
