Effect of low methoxyl pectin on the structural properties of the fat globules of cream: study of dispersed phase by size and morphology of particles

In this study, the effect of low methoxyl pectin addition oi the three levels including 0.2, 0.4 and 0.6% on the structural properties of cream with 45% fat globules was investigated. Structural study of the dispersed phase was performed using particle size distribution method and the morphological properties evaluated by optical microscopic images. The results show the effectiveness of low methoxyl pectin on the size distribution of fat globules in the cream. The mean volume-surface of ​​fat globules in pectin-free cream increased from 2.28 to 4.65 μm in the sample with 0.6% low methoxyl pectin. Optical microscopic images demonstrated the morphological of fat globules change from spherical and solitary to the agglomerated form. On the other hand, increasing of low methoxyl pectin levels caused to increase the irregularity of particles size distribution in the images obtained from microscopic observation. Fractal dimension was calculated as an indicator for complexity quantification based on microscopic images. An increase in fractal parameter observed with increasing levels of low methoxyl pectin in the cream. On the other hand, a relationship with high coefficient of determination was observed between the changes in particle size and fractal dimension.