Antibacterial, antioxidant activities of lactic acid bacteria-bioconversioned almond extract

Abstract

This study was about bioconversion of almonds by lactic acid bacteria. There are two bacteria used for bioconversion of almond extract: Lactiplantibacillus plantarum ATCC14917 and Lacticaseibacillus rhamnosus GG KCTC5033. Almond extract (AE) was inoculated with L. plantarum or L. rhamnosus GG for 3 days. AE inoculated with L. plantarum (LP-AE) and AE inoculated with L. rhamnosus GG (LR-AE) inhibited the growth of Salmonella Typhimurium and the growth of Yersinia enterocolitica by 30 and 75%, respectively compared to AE. LR-AE inhibited 30% of biofilm formation of S. Typhimurium and Y. enterocolitica compared to AE. Antioxidative activity of LP-AE and LR-AE was determined using the 2,2 '-zino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS) assay. ABTS radical scavenging activity of AE, LP-AE and LR-AE was 53.50%, 80.39% and 83.57%, respectively. The highest level of total polyphenol (89.72 mg Gallic Acid Equivalent (GAE)/g) and flavonoid (194.56 mg Quercetin Equivalent (QCE)/g) contents was found in LR-AE.