Abstract
A novel method to create nanoparticles from freeze-and air-dried mangosteen was developed to study the effects of these particles on the growth and protein formation of various gram-positive bacteria that act as foodborne pathogens. This new method produces freeze-and air-dried mangosteen peel nanoparticles that are prepared by a process based on a wet-milling technique, and these particles were tested on various gram-positive pathogenic bacteria. Our results indicated that the nanoparticles derived from freeze dried mangosteen contained higher antioxidant activity than nanoparticles derived from air-dried peels. The total phenol content in the freeze-dried nanoparticle extract was 1112.646 +/- 1.842 (mg gallic acid /g sample), whereas that in the air-dried extract was 479.744 +/- 2.564 (mg gallic acid/g sample). The total flavonoids in the mangosteen freeze-dried nanoparticle extract were 14.154 +/- 0.119 (mg catechin/g sample), whereas levels in the air-dried extract were 4.711 +/- 0.207 (mg catechin/g sample). The levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) were 95.707 +/- 0.070 and 94.303 +/- 0.074% for freeze-and air-dried mangosteen nanoparticle extracts, respectively. Similar levels were obtained for 2,4,6-tri (2-pyridyl)-s-triazine (ABTS), and these were 42.753 +/- 0.200 and 16.069 +/- 0.424 (g trolox/g sample) for freeze-and air-dried mangosteen nanoparticle extracts, respectively. Levels of ferric reducing antioxidant power (FRAP) were 17.806 +/- 0.056 and 6.696 +/- 0.085 (g trolox/g sample) for freeze-and air-dried mangosteen nanoparticle extracts, respectively. Whole protein bands from various bacteria disappeared on SDS-polyacrylamide gels when bacteria were cultured in medium containing both freeze-and air-dried mangosteen nanoparticles.