Centre Especial de Recerca Planta de Tecnologia dels Aliments (CERPTA), Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193-Bellaterra, Spain; Universidad de Nariño, Facultad de Ingeniería Agroindustrial, Ciudad Universitaria Torobajo, Pasto, Nariño 520002, Colombia.
Centre Especial de Recerca Planta de Tecnologia dels Aliments (CERPTA), Departament de Ciència Animal i dels Aliments, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193-Bellaterra, Spain.
J Dairy Sci. 2013 Apr;96(4):1984-1996. doi: 10.3168/jds.2012-5763. Epub 2013 Feb 15.
The objective of this study was to evaluate the effect of inulin as a fat replacer on the rheological properties, coagulation kinetics, and syneresis of milk gels. A randomized factorial design, replicated 3 times, with 3 inulin concentrations (0, 3, and 6%), 2 levels of fat (<0.2 and 1.5%), and 3 coagulation temperatures (27, 32, and 37°C) was used. The coagulation process was monitored using near-infrared spectrometry, small amplitude oscillatory rheometry, and visual coagulation indexes. The syneresis was evaluated by volumetric methods. Inulin addition increased the rates of aggregation and curd firming reactions in the casein gels. The observed effect, which was more evident on the aggregation reaction, depended on the concentration of inulin and the coagulation temperature. Addition of 6% inulin reduced the clotting time by approximately 26% and the time at which the gel reached a storage modulus equal to 30 Pa by approximately 36%. The optical parameter R'max, defined as the maximum value of change in light backscatter profile/change in time (where R' = dR/dt), was used to calculate an approximation of the temperature coefficients (Q10) for milk coagulation. Increasing fat concentration induced a consistent increase in all the optical, rheological, and visual parameters studied, although the observed trend was not statistically significant. The addition of inulin at a level of 6% produced a reduction in syneresis and increased the curd yield by approximately 30%. It was concluded that the addition of inulin affects the kinetics of milk coagulation and the cutting time and, therefore, the use of inline sensors such as near-infrared spectrometry may be necessary for optimal process control.
本研究旨在评估菊粉作为脂肪替代物对牛奶凝胶流变特性、凝固动力学和离浆的影响。采用随机析因设计，重复 3 次，菊粉浓度（0、3 和 6%）、脂肪水平（<0.2 和 1.5%）和凝固温度（27、32 和 37°C）各有 2 个水平。使用近红外光谱法、小振幅振荡流变学和视觉凝固指数监测凝固过程。通过体积法评估离浆。菊粉的添加增加了酪蛋白凝胶中聚集和凝块固化反应的速率。观察到的效果在聚集反应中更为明显，这取决于菊粉的浓度和凝固温度。添加 6%的菊粉可使凝块时间缩短约 26%，凝胶达到 30 Pa 储能模量的时间缩短约 36%。光学参数 R'max（定义为光背散射轮廓变化/时间变化的最大值（其中 R'=dR/dt））用于计算牛奶凝固的温度系数（Q10）的近似值。增加脂肪浓度会导致所有研究的光学、流变学和视觉参数一致增加，尽管观察到的趋势没有统计学意义。添加 6%的菊粉可减少离浆并使凝块产量增加约 30%。结论是，菊粉的添加会影响牛奶凝固的动力学和切割时间，因此可能需要使用近红外光谱等在线传感器进行优化的过程控制。
