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.
Milk and sodium alginate beads (SA) as encapsulation materials can improve the viability of Lacticaseibacillus acidophilus LAC5. The present study focused on interactive structural optimization of milk and SA-based beads for improved survival of L. acidophilus LAC5 in cheddar cheese. L. acidophilus was microencapsulated using varying concentrations of milk and SA, e.g., T0 (Milk/SA 0:0), T1 (Milk/SA 1/1:1), T2 (Milk/SA 1/2:1), T3 (Milk/SA 1/1:1.5), T4 (Milk/SA1/2:1.5), T5 (Milk/SA 1/1:2.0) and T6 (Milk/SA 1/2:2.0). Free and encapsulated L. acidophilus were compared for their survival in gastroenteric conditions. Structural and spectral analysis was performed using scanning electron microscope (SEM) and Fourier transform infrared spectrometry (FTIR). The free and encapsulated probiotics were incorporated into cheddar cheese. Organic acids were quantified using HPLC. The combination of SA and milk significantly (p < 0.05) improved the survival of L. acidophilus as compared to free cells. The increase in polymer concentration improved the structure of beads and the survival of probiotics. However, the release profile of beads decreased with the increase in polymer concentration. FTIR showed the presence of milk and SA in the beads. Better storage stability (108 CFU/mL) was observed for T6 in all the treatments as compared to free cells. The addition of encapsulated cells improved the sensory characteristics of cheese. This may help the local food industry to utilize native probiotic strains to be incorporated into probiotic foods with improved bio-accessibility.
Milk being a highly nutritious food in its natural form provides energy. There are various factors influencing the composition of milk: breed, stage of lactation, nutritional status, health, and milking intervals. A number of indigenous enzymes present in milk are being affected by stages of lactation period. Their concentration varies during early, mid and late lactation periods. This varied behavior ultimately affects the quality of dairy products. In this chapter, the level of milk enzymes: lipases and esterases, plasmin (PL), plasminogen (PLG) phosphatases (alkaline phosphatase ALP; acid phosphatase (ACP), lysozyme (LZ), lactoperoxidase (LP), xanthine oxidoreductase (XOR), and catalase (CAT) will be reviewed with respect to the stages of lactation periods.