Development of encapsulated probiotic bacteria isolated from vegetables

Abstract

Consumers' demand for non-dairy probiotic-containing foods is increasing due to their health benefits beyond nutrition. Milk-based products contain lactic acid bacteria as probiotic bacteria; however, non-dairy food sources also contain probiotic bacteria that may perform better than those identified from dairy foods. This study aimed to identify and characterize probiotic bacteria from non-dairy sources and encapsulate them to develop a starter culture. Different bacteria were isolated from Carrot, Beet, Gotukola and Lettuce using MRSA media. Morphological and biochemical characterisation were performed to screen potential probiotic strains. The screened probiotic isolates were examined for antimicrobial activity, acidity and bile tolerance. The best isolate was then selected for encapsulation. The extrusion technique was used to encapsulate the identified strain using sodium alginate. Finally, encapsulation efficiency was determined. Morphological and biochemical characteristics revealed that six out of ten isolates showed Gram positive, oxidase and catalase-negative properties. Isolate 101, 107 and 110 showed significantly higher survival percentages at pH 3 compared to the other strains. Isolate 101 showed a significantly (p<0.05) higher average diameter of inhibition zone, 11.5 mm and 10.73 mm against Salmonella typhimurium and Staphylococcus aureus, respectively. Isolated 101 did not show any significant (p>0.05) loss of viability at 0.3% and 0.7% bile salt compared to the control. However, strain 110 showed significant viability loss at 0.7% bile salt. The selected encapsulated 101 showed a 92% recovery efficiency. Molecular identification is needed to confirm the identity of the probiotic bacteria. This study demonstrates that LAB isolated from vegetables exhibited functional properties that can be used as potential encapsulated probiotics.