Survivability of Lactobacillus rhamnosus under stressed conditions as affected by taro starch (Colocasia esculenta) encapsulation

Abstract

ABSTRACT In the current study, taro starch was extracted and used for the encapsulation of probiotics to prolong their viability under stressed conditions. Taro starch and sodium alginate were used as wall materials for the encapsulation of Lactobacillus rhamnosus. Probiotic bacteria were encapsulated by the extrusion method, and obtained microbeads were subjected to various morphological, molecular, and structural characterization using Fourier transform infrared spectroscopy ;(FTIR), Scanning electron microscopy (SEM), and X-ray diffraction (XRD) technique. Furthermore, the viability of free and encapsulated probiotics was also accessed under simulated gastrointestinal conditions and in the food model (cheddar cheese). Average size microcapsules ranged from 6.16 ± 0.05 mm to 5.28 ± 0.03 mm. The encapsulation efficiency for taro and sodium alginate was recorded as 86.27% log CFU/g and 81.78% log CFU/g respectively. SEM micrographs exhibited entrapment of probiotics in wall materials. The surface of capsules was-irregular spherical structure FTIR spectra revealed broad characteristic peaks at 815 cm1, 1320 cm1, 1130 cm1, and ~ 1610 cm1. XRD images showed loss of crystalline structure following encapsulation. Higher probiotic viability was recorded under simulated gastrointestinal conditions for encapsulated probiotics compared to free probiotics. Likewise, a high probiotic count was observed in cheese fortified with encapsulated probiotics. Conclusively, taro starch wall material showed overall best results regarding the viability of probiotics under stressed conditions.