Although wheat endogenous lipids strongly impact bread quality, knowledge on their detailed distribution throughout the different stages of straight dough bread making is lacking. We here compared the lipid populations in hexane [containing free lipids (FLs)] and water-saturated butanol extracts [containing bound lipids (BLs)] of wheat flour, freshly mixed and fermented doughs, and bread crumb using high-performance liquid-chromatography [for nonpolar lipids, i.e. mainly free fatty acids (FFA) and triacylglycerols] and electrospray ionization tandem mass spectrometry (for polar lipids). Freshly mixed doughs had lower FL and higher BL levels than flour, a phenomenon referred to as lipid-binding. Furthermore, probably due to the disintegration of flour particles, the overall extractability of nonpolar lipids was higher in freshly mixed dough than in flour. Dough fermentation decreased the extractability of glycolipids, but increased that of nonpolar lipids and phospholipids. We hypothesize that these phenomena result from stretching of the gluten network due to gas cell expansion, which leads to the replacement of some lipids associated with gluten proteins by others. Baking increased the extractability of bound lysophospatidylcholine (LPC) levels, but decreased that of free FFA. This is probably due to in situ dissociation of amylose-LPC inclusion complexes and formation of amylose-FFA inclusion complexes during bread baking and cooling, respectively.

The approach and ESI-MS/MS methodology we developed provided valuable insights regarding the distribution of lipids at the different stages of bread making. Hence, it opens perspectives for future efforts to relate differences in lipid composition between wheat cultivars to their bread making quality.

尽管小麦内源性脂质强烈影响面包的品质，但仍缺乏有关纯面制面包各个阶段的详细分布的知识。我们在此使用高效液相色谱法比较了小麦粉，新鲜混合和发酵的面团以及面包屑中的己烷[含有游离脂质（FLs）]和水饱和丁醇提取物[含有结合脂质（BLs）]中的脂质种群。 [对于非极性脂质，即主要是游离脂肪酸（FFA）和三酰基甘油]和电喷雾电离串联质谱（用于极性脂质）。与面粉相比，新鲜混合的面团具有较低的FL和较高的BL水平，这种现象称为脂质结合。此外，可能由于面粉颗粒的分解，新鲜混合的面团中非极性脂质的总体可萃取性高于面粉。面团发酵降低了糖脂的提取能力，但增加了非极性脂质和磷脂的提取能力。我们假设这些现象是由于气体细胞膨胀引起的面筋网络拉伸而导致的，这导致与面筋蛋白相关的某些脂质被其他脂质替代。烘烤增加了结合的溶菌丝胆碱（LPC）水平的提取能力，但降低了游离FFA的提取能力。这可能是由于面包烘烤和冷却过程中，直链淀粉-LPC包合物的原位解离和直链淀粉-FFA包合物的形成。

我们开发的方法和ESI-MS / MS方法论提供了有关面包制作不同阶段脂质分布的宝贵见解。因此，它为将来将小麦品种之间的脂质组成差异与其面包制作质量相关联的努力开辟了前景。