Abstract The effect of ohmic heating (OH) parameters (voltage gradient, 2, 4, 6, 8, and 10 V cm−1) on the quality properties of dulce de leche (DL) was evaluated. Optical (L*, C*, and BI), rheological (flow curves and oscillatory tests) and thermal (differential scanning calorimetry) parameters as well as microstructure (optical microscopy) and modeling of the crystal size growth were evaluated during the storage time (60 days at 25 °C). Overall, OH processing resulted in lower optical (C* and BI) parameters, indicating a product with a lower intensity of caramel brown color. For the rheological assays, it was observed a decrease in the viscosity and consistency of the products (lower k values and higher n and G’ values). Finally, the OH-treated products presented higher numbers of lactose crystals of smaller size. The impact of OH was dependent on the voltage gradient, with a more pronounced effect on the product submitted to high electric field (10 V cm−1). Overall, OH is an interesting technology to be used in DL processing, being recommended the utilization of 8 V cm−1 of voltage gradient due to the better-quality properties.

中文翻译：

---

dulce de leche 中的欧姆加热技术：物理和热分布、微观结构以及晶体尺寸生长的建模

摘要 评估了欧姆加热 (OH) 参数（电压梯度，2、4、6、8 和 10 V cm-1）对牛奶酱 (DL) 质量特性的影响。在储存期间评估了光学（L*、C* 和 BI）、流变学（流动曲线和振荡测试）和热学（差示扫描量热法）参数以及微观结构（光学显微镜）和晶体尺寸生长的模型（ 25 °C 下 60 天）。总体而言，OH 处理导致较低的光学（C* 和 BI）参数，表明产品具有较低的焦糖棕色强度。对于流变分析，观察到产品的粘度和稠度降低（较低的 k 值和较高的 n 和 G' 值）。最后，经过 OH 处理的产品具有更多数量的较小尺寸的乳糖晶体。OH 的影响取决于电压梯度，对经受高电场 (10 V cm-1) 的产品有更明显的影响。总体而言，OH 是一种用于 DL 处理的有趣技术，由于具有更好的质量特性，建议使用 8 V cm-1 的电压梯度。