Foods, Vol. 14, Pages 3130: Carbon Dots from Dried German Chamomile Flower and Its Residual Biomass: Characteristics, Bioactivities, Cytotoxicity and Its Preservative Effect on the Refrigerated Precooked Baby Clam (Paphia undulata)
Foods doi: 10.3390/foods14173130
Authors:
Birinchi Bora
Suriya Palamae
Bin Zhang
Tao Yin
Jun Tae Kim
Jong-Whan Rhim
Soottawat Benjakul
The growing demand for natural and sustainable food preservatives has drawn interest in carbon dots (CDs) derived from plant sources. This study aimed to synthesize CDs from dried German chamomile flowers (DF) and residual biomass (RB) obtained after essential oil extraction using a hydrothermal process. Their characteristics, bioactivities and cytotoxicity were examined. Both DF-CDs and RB-CDs were spherical (7–10 nm), exhibited strong UV blocking properties and tunable fluorescence and were rich in polyphenolic functional groups, especially the –OH group. DF-CDs generally showed higher antioxidant capacity than RB-CDs as assayed by DPPH, ABTS radical scavenging activities, FRAP and metal chelation activity. Both CDs showed antibacterial effects toward pathogenic bacterial strains (Escherichia coli and Listeria monocytogenes) and spoilage bacteria (Shewanella putrefaciens and Pseudomonas aeruginosa) in a dose-dependent manner. Cytotoxicity was assessed in BJ human fibroblasts, and both CDs exhibited high biocompatibility (>88% viability at 1000 µg/mL). When both CDs at 300 and 600 ppm were applied in a precooked baby clam edible portion (PBC-EP) stored at 4 °C, microbial growth, TVB and TMA contents were lower than those of the control. The total viable count was still under the limit (5.8 log CFU/mL) for the sample treated with CDs at 600 ppm up to 9 days, while the control was kept for only 3 days. Furthermore, the lipid oxidation level (PV and TBARS value) of PBC-EP decreased with CD treatment, especially at higher concentrations (600 ppm). Therefore, chamomile-derived CDs could serve as a promising alternative for perishable seafood preservation.
Source link
Birinchi Bora www.mdpi.com
