Co-encapsulation of broccoli sprout extract nanoliposomes into basil seed gum: effects on in vitro antioxidant, antibacterial and anti-Listeria activities in ricotta cheese

Abstract

This study aimed to investigate the antioxidant and antibacterial activities (AOA and ABA) of broccoli sprout extract (BSE) nanoliposomes co-encapsulated into basil seeds gum (BSG). The characteristics of the BSE-loaded nanoliposomes and nano-capsules were firstly determined. Their functional (antioxidant and antibacterial) properties were tested in vitro, and their anti-Listeria effect (at 0.4 and 0.8% w/w) on ricotta cheese was evaluated. The produced nanoliposomes and nano-capsules were spherical in shape and did not tend to accumulate. The mean particle size, polydispersity index (PDI) and encapsulation efficiency (EE) were observed about 39.60 and 69.00 nm, 0.279 and 0.496, 85.73 and 88.46% for nano-capsules and nanoliposomes, respectively. The zeta potential (ζ) values were observed at −65.73 and −71.16 mV and therefore the nanoparticles had good stability and uniform particle size distribution. Encapsulation had no significant effect on total phenol and flavonoids content of the BSE. The amounts of these active compounds were in the range of 25.12–26.97 mg GAE/g dw and 6.84–6.95 mg QE/g dw, respectively. The free and encapsulated BSE displaying good AOA in the DPPH, ABTS and FRAP assays. Results of the ABA measured by inhibition zone diameter and the minimum inhibitory concentration (MIC) demonstrated that the free BSE had antibacterial action against the tested Gram-positive and Gram-negative bacteria, and the nano-encapsulation process led to improved ABA of this extract. The organic acids in BES indicated the presence of high levels of citric, malic and oxalic acids at 613, 98 and, 45 (mg/g dw), respectively. The BSE-loaded nanoparticles showed remarkable anti-Listeria activity in ricotta cheese, which their activity increased with increasing their concentration. In conclusion, BSE-loaded nanoliposomes and nano-capsules have potential interest to be used as natural antioxidants and preservatives for food applications.