Effect of acylglycerol composition on the microstructural and functional properties of bakery fats and margarines

Abstract

In the past, especially fats with a high content of unhealthy saturated fats were used to give bakery margarines ideal plastic properties. Therefore, this research treated the importance of the chemical fat composition for the microstructural and functional properties of bakery fats and margarines. Insight herein may lead to the development of more healthy products with a reduced saturated fatty acid level. Two research questions divided the work in two main parts. The first research question treated the possibilities to reduce the saturated fatty acid level by using monoacylglycerols, which are frequently used as emulsifiers in margarines. However, these components were not selected for their emulsifying properties, but for their crystallization and melting properties comparable to triacylglycerols. A monoacylglycerol containing substitution sample was selected based on its solid fat profile. However, a lower consistency than expected was obtained when using this sample in bakery margarine systems, due to the presence of mesomorphic phases. Moreover, a negative film formation in the mouth was observed when consuming products made with the substitution sample. Based on the results of the first part, a second research question was formulated focusing its attention more on triacylglycerols. In this second research part the importance of the triacylglycerol composition for the development of the desired structure and functionality of fat systems crystallized under shear was hereby investigated. A broad range of triacylglycerol blends were analyzed with the same SFC (35%) at either 15°C or 20°C. By varying the hardstock components in the blends different series were constructed focusing all on a variation of the triacylglycerol composition. The different analyses elucidated the importance of the triacylglycerol composition for the further microstructural built-up of fat systems crystallized under shear. For example, PPP-rich blends have a high crystallization rate under shear. On the contrary, SOS-rich blends behaved in a totally different way. Sintering of the fat crystal network was more pronounced for these samples and during storage at 20°C a strong grainy structure was formed