Functional and antimicrobial properties of bignay [Antidesma bunius (L.) Spreng.] extract and its potential as natural preservative in a baked product
The potential of bignay [Antidesma bunius (L.) Spreng.] fruit extract as a source of natural preservative was investigated. Bignay fruits, at red and fully mature stage, were analyzed for total phenolic content and free radical scavenging antioxidant activity. Crude and ethanol extracts from bignay fruits at concentrations 25%, 50%, 75% and 100% were screened for antimicrobial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas fluorescens, Bacillus subtilis, Candida albicans, and Aspergillus ochraceus using paper disc diffusion assay. Efficacy of the extract in controlling microbial growth in muffin was examined from 0 to 6 d of storage. Sensory evaluation of the baked product was also performed. Fully mature bignay fruit extract has higher total phenolic content (141.80 g CE 100 g-1) and antioxidant activity (87.10%) than red bignay, 84.43 g CE 100 g-1 and 75.87%, respectively. Largest zones of inhibition were produced by ethanol (16.50-25.00 mm and 15.83-25.17 mm) and crude (13.67- 21.67 mm and 15.50-23.83 mm) extracts from red bignay against P. fluorescens and B. subtilis, respectively. Red bignay extracts with pH adjusted to 6.5 also exhibited antibacterial effects against P. fluorescens and B. subtilis. Addition of 5% bignay extract can significantly inhibit the growth of microorganisms in a baked product and result in softer and more acceptable baked product. Bignay can be used as a natural ingredient with significant biological function due to its antioxidant and antimicrobial properties.