Evolution of soluble solid content and evaporation rate curves during the manufacture of dulce de leche (dl)

Abstract Dulce de leche is an evaporated dairy product that can be manufactured in different types of pots or pans. The manufacturing endpoint for dulce de leche can be determined by measuring the soluble solids content. We investigated the evaporation rates and the evaporative capacity of atmospheric pressure evaporators (pans) during the manufacture of dulce de leche. During manufacturing, four different formulations were subjected to soluble solids content determination by refractometry. In addition, the mass balance was used to determine the yield and evaporation rate. A low coefficient of variation and amplitude was found for soluble solids content, indicating standardization and uniformity during fabrication. We also observed a gradual increase in the latter throughout manufacture, without significant differences between the times. The evaporated water mass rate and its respective equation allow to reproduce the same characteristics of the experimental product in experimental and industrial production of dulce de leche.摘要 焦糖牛奶酱（dulce de leche）是一种蒸发型乳制品，可通过不同类型的煮锅或平底锅进行生产制造。该产品的生产终点可通过测量可溶性固形物含量来判定。本研究针对焦糖牛奶酱生产过程中常压蒸发器（煮锅）的蒸发速率与蒸发能力展开了调研。生产过程中，研究人员采用折光法对四种不同配方的样品进行了可溶性固形物含量检测；此外，通过物料衡算来计算产品得率与蒸发速率。检测结果显示，可溶性固形物含量的变异系数与极差均较低，表明生产过程具备标准化与均一性。同时研究还发现，在整个生产周期中，可溶性固形物含量呈逐步上升趋势，且不同采样时间点间无显著差异。所得到的水蒸发质量速率及其对应计算公式，可用于在焦糖牛奶酱的实验性与工业化生产中复现实验产品的各项特性。