College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, Henan, P. R. China.
J Food Sci. 2024 Jul;89(7):4345-4358. doi: 10.1111/1750-3841.17150. Epub 2024 Jun 9.
Freezing is a crucial step in the process of frozen foods. In this study, the effects of different freezing methods, including liquid nitrogen immersion freezing (LF), quick-freezing machine freezing (QF), packaging immersion freezing (PF), and ultralow temperature refrigerator freezing (UF), and freezing time (0, 15, 30, and 60 days) on the textural properties, dynamic rheological properties, water distribution, and structure of dough and the quality of end steamed bread were evaluated. Freezing resulted in a decline in the physicochemical properties of dough. UF- and QF-doughs had higher storage modulus and loss modulus, compared with PF- and LF-doughs. LF enhanced the textural attributes of the dough, resulting in reduced hardness and increased springiness. At 15 days of freezing, QF- and LF-doughs exhibited a compact and continuous structure with a smooth surface. Additionally, the correlation analysis elucidated that the weight loss rate and the bound water content of the dough had discernible impacts on the texture of both the dough and the resulting steamed bread. Overall, LF demonstrated a relatively high freezing efficiency and effectively maintained the quality of the dough for up to 15 days of freezing. These results offer valuable insights for the applications of freezing methods and time in frozen foods.
冷冻是冷冻食品加工过程中的一个关键步骤。在这项研究中，研究了不同冷冻方法（液氮浸渍冷冻（LF）、速冻机冷冻（QF）、包装浸渍冷冻（PF）和超低温冰箱冷冻（UF））和冷冻时间（0、15、30 和 60 天）对面团的质构特性、动态流变特性、水分分布和结构以及最终蒸制馒头品质的影响。冷冻导致面团的理化性质下降。与 PF-和 LF-面团相比，UF-和 QF-面团的储能模量和损耗模量更高。LF 增强了面团的质地属性，导致硬度降低，弹性增加。在冷冻 15 天的情况下，QF-和 LF-面团呈现出紧密连续的结构，表面光滑。此外，相关分析表明，面团的失重率和结合水含量对面团的质地以及蒸制馒头的质地有明显的影响。总的来说，LF 表现出相对较高的冷冻效率，并能在冷冻 15 天内有效保持面团的质量。这些结果为冷冻方法和时间在冷冻食品中的应用提供了有价值的见解。
