Laboratory of Food Quality and Safety Research, Department of Logistics, Faculty of Military Leadership, University of Defence, Kounicova 65, 662 10 Brno, Czech Republic.
Centre of Polymer Systems, University Institute, Tomas Bata University in Zlín, Tř. T. Bati 5678, 760 01 Zlín, Czech Republic; Department of Production Engineering, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 5669, 760 01 Zlín, Czech Republic.
J Dairy Sci. 2023 Aug;106(8):5298-5308. doi: 10.3168/jds.2022-22833. Epub 2023 Jul 4.
Sterilized processed cheese is a specific dairy product with a prolonged shelf life intended for regular retail offer but also as food provisions for armies during peacetime, as well as during crisis and emergency situations, and for storage in state material reserves. Storage requirements are usually defined as ≤25°C for at least 24 mo. One of the ways to achieve such a shelf life is sterilization. Therefore, the aim of the work was to describe, for the first time in the available scientific literature, in situ changes in the viscoelastic properties of spreadable melt (34% wt/wt DM content, 45% wt/wt fat in DM content, and 14% wt/wt protein content) during an increase in temperature (target temperature 122°C), holding at sterilization temperature (20 min) and subsequent cooling (to ~30°C). While increasing to the target sterilization temperature, a significant decrease occurred in the storage and loss moduli values. Both moduli started to increase again during the target sterilization temperature period and during the whole cooling phase. The values of the storage and loss moduli were significantly higher at the end of the cooling of the sterilized product, and conversely, the phase angle value was lower compared with the melt before sterilization. As a result of sterilization, an increase occurred in the levels of markers of the Maillard reaction complex and lipid oxidation processes. The value of hardness, corrected stress, and elongational viscosity also increased compared with nonsterilized products. As a result of sterilization, the flavor worsened and sterilized processed cheeses showed darker (brownish) color. However, even after sterilization, the products were evaluated as acceptable for consumers and maintained their spreadability.
经消毒处理的加工奶酪是一种具有延长保质期的特定乳制品，旨在进行常规零售供应，也可作为军队在和平时期、危机和紧急情况下的食品供应，还可用于国家物资储备的储存。通常规定的储存要求为温度≤25°C，至少 24 个月。实现这种保质期的方法之一是消毒。因此，本工作的目的首次在现有科学文献中描述了涂抹型融化物（34wt%wt/干物质含量、45wt%wt/干物质含量中的脂肪和 14wt%wt/蛋白质含量）的粘弹性特性在升温过程中的原位变化（目标温度 122°C）、保持在消毒温度（20 分钟）和随后的冷却（至约 30°C）。在升温至目标消毒温度的过程中，储能模量和损耗模量的值显著降低。在目标消毒温度期间，这两个模量开始再次增加，并且在整个冷却阶段也是如此。消毒产品冷却结束时，储能模量和损耗模量的值显著更高，相反，与消毒前的融化物相比，相角值更低。由于消毒，美拉德反应复合物和脂质氧化过程的标志物水平增加。与未消毒产品相比，硬度、校正应力和拉伸黏度的值也增加。由于消毒，奶酪的风味变差，消毒后的加工奶酪颜色更深（呈褐色）。然而，即使经过消毒，这些产品仍被评估为消费者可接受的产品，并保持其可涂抹性。
