Hydrolysis, Microstructural Profiling and Utilization of Cyamopsis tetragonoloba in Yoghurt

Abstract

The present study investigates the hydrolysis, microstructural profiling and utilization of guar gum (Cyamopsis tetragonoloba) as a prebiotic in a yoghurt. Guar galactomannans (GG) was purified and partially depolymerized using an acid, alkali and enzyme to improve its characteristics and increase its utilization. The prebiotic potential of hydrolyzed guar gum was determined using Basel and supplemented media. Crude guar galactomannans (CGG), purified guar galactomannans (PGG), base hydrolyzed guar galactomannans (BHGG), acid hydrolyzed guar galactomannans (AHGG) and enzymatic hydrolyzed guar galactomannans (EHGG) were analyzed using scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Yoghurt was prepared with a starter culture and incorporating guar gum, its hydrolyzed forms (0.1, 0.5 and 1%) and Bifidobacterium bifidum. The results showed that PHGG significantly improved the viability of B. bifidum. SEM revealed a significant change in the surface morphology of guar gum after acidic and enzymatic hydrolysis. Enzymatic hydrolysis developed a well-defined framework within guar gum molecules. The XRD pattern of CGG, PGG and AHGG presented an amorphous structure and showed low overall crystallinity while EHGG and BHGG resulted in slightly increased crystallinity regions. FTIR spectral analysis suggested that, after hydrolysis, there was no major transformation of functional groups. The addition of the probiotic and prebiotic significantly improved the physiochemical properties of the developed yoghurt. The firmness, cohesiveness, adhesiveness and syneresis were increased while consistency and viscosity were decreased during storage. In sum, a partial hydrolysis of guar gum could be achieved using inexpensive methods with commercial significance.