Papers by Adem Gharsallaoui
Applied Sciences
The global demand for safe and healthy food with minimal synthetic preservatives is continuously ... more The global demand for safe and healthy food with minimal synthetic preservatives is continuously increasing. Natural food antimicrobials and especially essential oils (EOs) possess strong antimicrobial activities that could play a remarkable role as a novel source of food preservatives. Despite the excellent efficacy of EOs, they have not been widely used in the food industry due to some major intrinsic barriers, such as low water solubility, bioavailability, volatility, and stability in food systems. Recent advances in nanotechnology have the potential to address these existing barriers in order to use EOs as preservatives in food systems at low doses. Thus, in this review, we explored the latest advances of using natural actives as antimicrobial agents and the different strategies for nanoencapsulation used for this purpose. The state of the art concerning the antibacterial properties of EOs will be summarized, and the main latest applications of nanoencapsulated antimicrobial age...
Journal of Controlled Release
International Journal of Biological Macromolecules
Journal of Food Processing and Preservation
Journal of Food Process Engineering
Colloids and surfaces. B, Biointerfaces, 2018
The present study aims to evaluate the interactions between four exopolysaccharides (EPS) produce... more The present study aims to evaluate the interactions between four exopolysaccharides (EPS) produced by probiotic bacteria and sodium caseinate (Cas) in order to simulate their behavior in dairy products. Complexation between the produced EPS samples and Cas was investigated as a function of polysaccharide to protein ratio. The highest turbidity and average size of complexes were formed at an EPS/Cas ratio of 3 (corresponding to 1 g/L of EPS and 0.33 g/L of Cas) as a result of the combination of individual complexes to form aggregates. Zeta potential measurements and Cas surface hydrophobicity results suggested that complex formation occurred essentially through electrostatic attractions with a possible contribution of hydrophobic interaction for EPS-GM which was produced by Bacillus tequilensis-GM. Afterwards, the effect of pH on the complexation between biopolymers was studied when EPS and Cas concentrations were maintained constant at 1 and 0.33 g/L, respectively. pH was adjusted t...
Food chemistry, 2017
In order to understand the effect of pH on the formation of electrostatic complexes between lysoz... more In order to understand the effect of pH on the formation of electrostatic complexes between lysozyme and low methoxyl (LM) pectin, mixtures were prepared at a fixed lysozyme concentration (0.714g.L(-1)) by progressive addition of LM pectin (from 0 to 4g.L(-1)). Turbidity analysis allowed to determine specific conditions of pH and lysozyme/LM pectin ratio for optimal complex aggregation. The intrinsic fluorescence enhancement observed upon binding of LM pectin to lysozyme was correlated with the formation of intermolecular aggregates. Conversely, the intrinsic fluorescence decrease observed at higher LM pectin amounts was correlated with the dissociation of intermolecular aggregates. UV absorption spectroscopy showed modifications in lysozyme conformation during both the aggregation phase and the dissociation phase. The role of electrostatic interactions in the formation of lysozyme/LM pectin complexes is discussed in relation to the overall structure and the charge density profile o...
Food chemistry, 2017
The aim of this study is to investigate the potential of complexation to encapsulate nisin (5g/L ... more The aim of this study is to investigate the potential of complexation to encapsulate nisin (5g/L concentration) using spray-drying technique and to evaluate how complexation with pectin or alginate (2g/L concentration) can preserve nisin structure and antimicrobial activity. Spray-drying of nisin-low methoxyl pectin or nisin-alginate electrostatic complexes has led to the microencapsulation of the peptide in different networks that were highly influenced by the polysaccharide type. Turbidity and particle size measurements indicated that while spray-drying promoted the aggregation of nisin-pectin complexes, it favored the dissociation of nisin-alginate aggregates to form individual complexes. Structural changes of nisin induced by complexation with pectin or alginate and spray-drying were studied by using UV-Vis absorption and fluorescence spectroscopy. The results showed that complexation with pectin or alginate preserved nisin structure as well as its antimicrobial activity during ...
Food Research International, 2016
Complexation study of lysozyme (0.714g/L) by sodium alginate at pH7 showed that aggregates format... more Complexation study of lysozyme (0.714g/L) by sodium alginate at pH7 showed that aggregates formation was a two-phase process. The first phase (from 0 to 0.1g/L sodium alginate) corresponded to the combination of individual complexes to form aggregates which caused an increase of turbidity and average size and a rapid sedimentation. Charge neutralization estimated by ζ-potential measurements occurred at 0.1g/L sodium alginate concentration. The second phase (from 0.1 to 4g/L of sodium alginate) was characterized by the formation of aggregates having a less dense structure with higher average size despite the drop in turbidity and the high dispersion in the medium. Lysozyme enzymatic activity decreased upon complexation with sodium alginate but was fully recovered after calcium chloride addition. In order to check whether lysozyme reversible inactivation was only due to substrate diffusion limitation or to conformational changes upon complexation, fluorescence and UV-Vis absorption measurements were performed. Moreover, lysozyme/sodium alginate complexes were used to manufacture an edible antimicrobial film to target lysozyme sensitive microorganisms.
Carbohydrate Polymers, 2016
Coacervation between sodium caseinate (CAS) and low methoxyl pectin (LMP) at pH 3 was investigate... more Coacervation between sodium caseinate (CAS) and low methoxyl pectin (LMP) at pH 3 was investigated as a function of protein/polysaccharide ratio. The highest amount of complex coacervates was formed at a CAS/LMP ratio of 2 at which the ζ-potential value was zero and the turbidity reached its highest value. Then, the properties of films based on these complex coacervates were studied. Coacervation resulted in decreasing water content and water sorption of films as the protein concentration increased. The mechanical properties of films were highly influenced by the formation of electrostatic complexes. The highest values of Young's modulus (182.97± 6.48MPa) and tensile strength (15.64±1.74MPa) with a slight increase of elongation at break (9.35±0.10%) were obtained for films prepared at a CAS/LMP ratio equal to 0.05. These findings show that interactions between LMP and CAS can be used to develop innovative packaging containing active molecules.
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Papers by Adem Gharsallaoui