Microencapsulation of probiotic organisms within a conjugated whey protein hydrolysate matrix

Dairy foods enriched with probiotics are receiving considerable attention as modulators of the gut microbiota and host health. Hence, with increasing demand for probiotic foods, it is essential to develop novel products with added value in terms of enhanced health benefits and functionality. In addition, such products can benefit all types of consumer groups. In this study, conjugated whey protein hydrolysate (WPH10), which was identified in our previous study to have higher bioactive attributes, was used as an encapsulant to entrap probiotic cultures; Bifidobacterium animalis ssp. lactis ATCC27536 and Lactobacillus acidophilus ATCC4356, through spray drying process. Each culture was propagated at 37°C for 72 h, under anaerobic conditions, and the cell pellets were suspended in PBS to achieve 1010 cfu/mL. These cell suspensions were mixed in the ratio of 1:1 and inoculated into the conjugated WPH10 solution. The solution was spray dried in 2L batches using a Niro drier with an inlet and outlet temperature of 200°C and 90 ± 5°C, respectively. The final dried product was assessed for moisture content, functionality (solubility and wettability) and cell viability using standard plating procedure. All experiments were conducted in triplicates and one-way ANOVA was applied to differentiate the mean values. In addition, the microcapsules were observed under scanning electron microscope (SEM) to examine the structural conformity. Following spray drying, moisture content in the final product was 0.7 ± 0.14%. The solubility and wettability were considerably higher (91.5 ± 0.4% and 49 ± 2min respectively) as compared with WPH10 alone (77.28 ± 0.4% and 61 ± 2 min respectively). The mean probiotic counts (mixed population) before and after spray drying were 10.37 log cfu/mL and 8.50 log cfu/g, respectively. Under SEM, the outer structure of the capsules presented a round continuous surface with formation of irregular concavities. The conjugated whey protein hydrolysate is thus demonstrated as a carrier for probiotic bacteria. Such a product having even improved functionality, can offer opportunities as an ingredient for developing novel health formulations