Physical and chemical properties of milkfat and phytosterol esters blends
- 作者：Juliana N. Rodrigues ; Rosâ ; ngela P. Torres ; Jorge Mancini-Filho ; Luiz A. Gioielli
- 关键词：Milkfat ; Phytosterol esters ; Solid fat content ; Consistency ; Crystal structure
- 刊名：Food Research International
- 出版年：2007
- 期刊代码：53_09639969
- 类别：abs
- 出版时间：July 2007
- 卷：40
- 期：6
- 页码：748-755
- 文件大小：597 K
摘要
Over the past few decades, consumption of butter has declined due to its high content of saturated fatty acids and cholesterol. Opposingly, phytosterol esters (PE) have been used as a food ingredient for their effectiveness in lowering plasma cholesterol levels. The objective of this work was to evaluate the effects of the addition of PE on the physical and chemical properties of milkfat (MF). The fatty acid and sterol compositions were determined by gas chromatography (GC). A constant speed texture analyser was used to evaluate consistency. Solid fat content (SFC) was determined by nuclear magnetic resonance (NMR) and crystal structure was observed with polarized light microscopy. Results showed that β-sitosterol (33.5%), campesterol (23.6%), and stigmasterol (14.9%) were the most abundant sterols in the PE blend. Blends containing MF and PE presented a softer consistency than pure MF at low temperatures. Despite the higher SFC, PE caused a decrease in the SFC of MF. The images of MF, PE, and their blends obtained by polarized light microscopy showed the influence of temperature on crystal size and number. This method revealed the particular crystalline structure of PE, formed by a solid, dense crystal network, with amorphous crystals of varied sizes, different from crystal structures generally observed in fats. The high SFC and low consistency of PE may indicate a weak crystal network, probably due to the presence of different molecular structures.