Enhancing functional properties of probiotic yoghurt with curry leaves (Murraya koenigii) extract: A study on antimicrobial and antioxidant activity

The incorporation of natural plant extracts in dairy products is gaining attention for their potential health benefits. This study evaluates the effect of curry leaves (Murraya koenigii) extract on the antimicrobial and antioxidant properties of probiotic yoghurt while assessing its sensory acceptability. The antimicrobial activity of curry leaves extract was tested against S. aureus, Salmonella sp., E. coli, Rhodotorula sp., Penicillium sp., and Aspergillus sp. The extract exhibited antibacterial activity against S. aureus and Salmonella sp., with the highest inhibition at 300 mg/ml, but showed no effect against E. coli and fungal strains. The antioxidant potential of curry leaves extract was determined using the DPPH radical scavenging assay, which showed a concentration-dependent increase in inhibition, with an IC50 value of 54.23 μg/ml. Probiotic yoghurt enriched with CLE demonstrated enhanced antimicrobial properties, particularly against S. aureus and Salmonella sp., while maintaining comparable activity against E. coli to that of control yoghurt. Sensory evaluation revealed that curry leaves extract incorporated probiotic yoghurt was well-accepted in terms of appearance, texture, flavor, and overall acceptability. These findings highlight the potential of curry leaves extract as a functional ingredient in probiotic yoghurt, contributing to the development of healthier and more sustainable dairy products with enhanced antimicrobial and antioxidant properties.