Institute of Mechanical Process Engineering and Mechanics, Karlsruhe Institute of Technology, 76131 Karlsruhe, Germany.
Bruker BioSpin GmbH & Co. KG, 76275 Ettlingen, Germany.
Molecules. 2024 Jun 26;29(13):3024. doi: 10.3390/molecules29133024.
To reduce unwanted fat bloom in the manufacturing and storage of chocolates, detailed knowledge of the chemical composition and molecular mobility of the oils and fats contained is required. Although the formation of fat bloom on chocolate products has been studied for many decades with regard to its prevention and reduction, questions on the molecular level still remain to be answered. Chocolate products with nut-based fillings are especially prone to undesirable fat bloom. The chemical composition of fat bloom is thought to be dominated by the triacylglycerides of the chocolate matrix, which migrate to the chocolate's surface and recrystallize there. Migration of oils from the fillings into the chocolate as driving force for fat bloom formation is an additional factor in the discussion. In this work, the migration was studied and confirmed by MRI, while the chemical composition of the fat bloom was measured by NMR spectroscopy and HPLC-MS, revealing the most important triacylglycerides in the fat bloom. The combination of HPLC-MS with NMR spectroscopy at 800 MHz allows for detailed chemical structure determination. A rapid routine was developed combining the two modalities, which was then applied to investigate the aging, the impact of chocolate composition, and the influence of hazelnut fillings processing parameters, such as the degree of roasting and grinding of the nuts or the mixing time, on fat bloom formation.
为了减少巧克力制造和储存过程中不必要的脂肪花斑，需要详细了解油脂的化学组成和分子流动性。尽管几十年来人们一直在研究巧克力产品中脂肪花斑的形成及其预防和减少问题，但分子水平上仍有一些问题有待解答。含有坚果馅料的巧克力产品特别容易出现不想要的脂肪花斑。脂肪花斑的化学成分被认为主要由巧克力基质的三酰基甘油组成，它们迁移到巧克力表面并在那里重新结晶。油从馅料中迁移到巧克力中作为脂肪花斑形成的驱动力是讨论的另一个因素。在这项工作中，通过 MRI 研究并证实了这种迁移，而脂肪花斑的化学组成则通过 NMR 光谱和 HPLC-MS 进行了测量，揭示了脂肪花斑中最重要的三酰基甘油。HPLC-MS 与 800 MHz 的 NMR 光谱相结合可以进行详细的化学结构测定。开发了一种结合两种模式的快速常规方法，然后应用于研究老化、巧克力成分的影响以及榛子馅料加工参数（如坚果的烘烤和研磨程度或混合时间）对脂肪花斑形成的影响。
