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Effect of ultrasound on antimicrobial properties of whey protein‐totarol nanogel
Author(s) -
Guo Mingruo,
Ma Shuang
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.lb635
Subject(s) - chemistry , whey protein isolate , antimicrobial , whey protein , nanogel , food science , organic chemistry , drug delivery
Totarol is a natural antimicrobial compound extracted from the heartwood of the Totara tree. The effects of whey protein‐totarol nanogel treated with ultrasound on the growth of Staphylococcus aureus (S. aureus) were investigated. The particle size of WPI‐Totarol nanogels was reduced by ultrasound treatment from 31.24 ± 5.31 nm to 24.20 ± 4.02 nm and its distribution was also narrowed by the treatment. The data of viscosity and modulus indicated that the flow behaviors of WPI‐Totarol nanogels seemed to be a Newtonian and exerted a typical viscoelastic fluid at protein content of 15% (w/v). Rheological properties were more insensitive to ultrasonic time. Time‐killing assays, agar diffusion tests, the cell membrane damage analysis and microstructure were also exploited to study the antibacterial properties of WPI‐Totarol nanogel. The minimal inhibitory concentration (MIC) of WPI‐Totarol after ultrasound treatment decreased from 4 to 2 μg/mL compared to that without ultrasound treatment. WPI‐Totarol nanogels treated with ultrasound resulted in a significant (P<0.05) decrease in time‐killing after 24 h. The agar diffusion results showed that the inhibition zones of WPI‐Totarol nanogels were 12 and 36 mm for untreated and treated with ultrasound, respectively. The bacterial membrane damages and the microstructure changes also proved that WPI‐Totarol nanogels treated with ultrasound had strong antibacterial activities against S. aureus and the antibacterial effectiveness enhanced with the increasing of ultrasonic time. These findings suggested that WPI‐Totarol nanogels treated with ultrasound were more effective against S. aureus than untreated ones. Support or Funding Information The financial support for this project was provided by the Ministry of Science and Technology of China (Project # 2013BAD18B07)