Antimicrobial Activity of Encapsulated Mexican Oregano (Lippia berlandieri Schauer) Essential Oil Applied on Bagels

Abstract

Several in vitro studies of Mexican oregano essential oil (MOEO) have demonstrated its effectiveness as an antimicrobial. On the other hand, the encapsulation technique of emulsification could be used to mask the intense flavor of MOEO, protect it from physicochemical degradation, and release gradually its antimicrobial components. In the present study, emulsions were elaborated with two encapsulating agents, pectin or Arabic gum, with five concentrations of MOEO (0%, 5%, 7.5%, 10%, or 15% w/w). Emulsions were characterized by density, viscosity, particle size distribution, creaming index, and peroxide index. Emulsions were applied, in a 3:1 ratio, on the surface of two formulations of bagel, one with wheat flour (BW) and another with wheat flour and oats (BWO). Bagels were characterized by water activity, moisture content, and hardness. The antimicrobial activity of MOEO encapsulated by emulsification on Penicillium expansum on the surface of the bagels was determined. In addition, a sensory analysis of the bagels was carried out using a hedonic scale. All physicochemical properties of the emulsions had a significant difference (p < 0.05) because of the encapsulating agent used (pectin or Arabic gum). Emulsions stabilized with Arabic gum were more stable over time than the ones with pectin. The application of the emulsions on the surface of the bagels did not show a statistical difference (p > 0.05) in the physicochemical properties of the breads. The growth of P. expansum was delayed for up to 5 or 6 days in bagels with wheat flour and Arabic gum as encapsulating agent. Both systems, BW and BWO, atomized with MOEO emulsions at high concentrations (MOEO 15% w/w) were well accepted by the panel of judges when these were evaluated on day 0 (freshly baked bread) but not after 6 days of their elaboration.

Untitled

“…Shehata et al, 2013 [14] investigated the effect of essential oil of ginger, black cumin, thyme, clove and watercress on the performance of Nile tilapia (Oreochromis niloticus) fingerlings fish and evaluated the antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Listeria monocytogenes, Lactococcus lactis, Bacillus cereus, etc., and this study proved the addition of thyme oil 0.25% to fish diet reduces feed consumption ratio (FCR) and improves body weight gain, blood parameters like protein, albumin, aspartate aminotransferase, and alanine aminotransferase. Similarly, (Salgado-Nava et al, 2020) [11] prepared microencapsulated Mexican oregano essential oil powder and established antibacterial activity against Penicillium expansum. MEBOP and METOP were investigated to evaluate their antibacterial activity against aqua pathogenic bacteria strain Vibrio harvey, Vibrio parahaemolyticus, Bacillus cereus, Aeromonas sp, E. coli, and Salmonella sp.…”

Essential oils: An eco‐friendly alternative for controlling toxigenic fungi in cereal grains

“…BW bagels on day 0 presented an average score of 6 (“I like it very much”) as evaluated by the judges, and BWO bagels delivered a score of 5.5 (“I like it very much/I like it moderately”). However, the acceptability of bagels with pectin or gum arabic emulsions with oregano essential oil was low due to changes in texture (Salgado‐Nava et al., 2020).…”

Development of Antifungal Packaging From Low‐Density Polyethylene With Essential Oil of Oregano and Potassium Sorbate

“…and Aspergillus spp. [18]; and Penicillium expansum and Aspergillus [19,20]. In this regard, EOs have been incorporated by different methods into LDPE films as antimicrobial agents.…”