van der Sman R G M, van den Oudenhoven Bjorn
Wageningen Food & Biobased Research, the Netherlands.
Lamb-Weston Meijer, Kruiningen, the Netherlands.
Curr Res Food Sci. 2023 Feb 25;6:100466. doi: 10.1016/j.crfs.2023.100466. eCollection 2023.
In this study we report on the analysis of dust formation, a quality problem arising in the industrial processing of par-fried, frozen french fries. This dust constitutes fractured pieces broken off the crust during finish frying. We claim that this dust problem has many similarities with flaking arising during the final-baking of par-baked french baguettes, i.e. the two problems are governed by the same physical principles. Inspired by the hypotheses behind flaking, we have made an experimental design, where we have perturbed the operating conditions of an industrial processing line of french fries. The measured dust during finish frying is correlated with the physical properties of the crust, measured in the different unit operations of the industrial processing line, and the operating conditions. We have shown that dust is non-linearly correlated to 1) the moisture content of the crust as influenced by drying and par-frying, and 2) the freezing rate in the industrial tunnel freezer. Remarkably, the amount of dust decrease with the increase of frozen storage time, which we have explained via viscoelastic relaxation of locked-in stress - mediated by moisture migrating from core to crust. This decay is shown to be independent of pretreatments, which only determines its starting value. With the given relations industry can in principle control the dust problem, but these measures have to be weighed against their effects on other objectives of the industry.
在本研究中，我们报告了对粉尘形成的分析，这是预炸冷冻薯条工业加工过程中出现的一个质量问题。这种粉尘是在最终油炸过程中从外皮脱落的破碎碎片。我们认为，这个粉尘问题与半烘焙法棍面包最终烘焙过程中出现的剥落现象有许多相似之处，即这两个问题受相同的物理原理支配。受剥落背后假设的启发，我们进行了一项实验设计，在该设计中扰动了薯条工业加工生产线的操作条件。最终油炸过程中测得的粉尘与外皮的物理性质相关，外皮的物理性质是在工业加工生产线的不同单元操作中测量的，同时也与操作条件相关。我们已经表明，粉尘与以下因素呈非线性相关：1）干燥和预炸影响下的外皮水分含量；2）工业隧道式冷冻机中的冷冻速率。值得注意的是，粉尘量随着冷冻储存时间的增加而减少，我们通过水分从芯部迁移到外皮介导的锁定应力的粘弹性松弛对此进行了解释。这种衰减表明与预处理无关，预处理仅决定其起始值。基于给定的关系，工业原则上可以控制粉尘问题，但这些措施必须权衡其对行业其他目标的影响。
