*article still being written*
Woody’s Consumer Brands consider the use of Lamirsa’s Ethyl Lauroyl Arginate as a food preservative in one of its products. Here we try and understand its background and the mechanism behind its functionality as a food preservative.
In the 1980’s a Spanish company, based in Barcelona, LAMIRSA, began research on the use of cationic surfactants to prevent the proliferation of a wide variety of bacteria molds and yeast in foods.
A surfactant is a surface-active agent. The molecule comprises of a head and one or two tails.Surfactants are classified according to the characteristics of the polar head group being nonionic, anionic, cationic or amphoteric.
QAC’s interact with microorganisms predominantly in relation to the cell wall in a destructive way which makes them ideal anti-microbial agents.
“QACs are membrane active agents (i.e., with a target site predominantly at the cytoplasmic (inner) membrane in bacteria or the plasma membrane in yeasts). The following sequence of events occurs with microorganisms exposed to cationic agents:
(i) adsorption and penetration of the agent into the cell wall;
(ii) reaction with the cytoplasmic membrane (lipid or protein) followed by membrane disorganization;
(iii) leakage of intracellular low-molecular-weight material;
(iv) degradation of proteins and nucleic acids; and
(v) wall lysis (the cell wall or membrane ruptures and the cell disintegrates) caused by autolytic enzymes (its own enzymes or enzyme from another of the same molecule).
There would be a loss of structural organization and integrity of the cytoplasmic membrane in bacteria, together with other damaging effects to the bacterial cell.
Actually, most studies on membrane damage evaluated the effects of biocides on protoplasts and spheroplasts suspended in various solutes. QACs caused lysis of spheroplasts and protoplasts suspended in sucrose. The cationic agents interact with phospholipid (the phosphate group being the negatively-charged polar head) components in the cytoplasmic membrane, thereby producing membrane distortion and protoplast lysis under osmotic stress. Isolated membranes, however, did not undergo disaggregation (seperation out) on exposure to QACs. Some polymeric quaternary ammonium compounds such as polyquaternium-1, a quaternary ammonium polymeric compound, and myristamidopropyl dimethylamine, were shown to induce lysis of spheroplasts of S. marcescens, but not those of C. albicans. Damage to the membrane was sufficient to cause K+ leakage but this injury was not always sufficient to cause spheroplasts lysis. Adsorption of dioctadecyldimethyl ammonium bromide (DODAB) cationic bilayers onto bacterial cells changed the sign of the cell surface potential from negative to positive and a clear relationship between positive charge on bacterial cells and death was described. Regarding the mechanism of DODAB action, neither bacterial cell lysis nor DODAB vesicle disruption took place in contrast to the mechanism of action for single chained cationic surfactants.” (Carmona-Ribeiro, A. M. and Dias de Melo Carrasco, L.)
ETHYL LAUROYL ARGINATE
Ethyl lauroyl arginate is synthesised by esterifying arginine with ethanol, followed by reacting the ester with lauroyl chloride. The resultant ethyl lauroyl arginate is recovered as hydrochloride salt and is a white, solid product which is filtered off and dried.
Carmona-Ribeiro, A. M. and Dias de Melo Carrasco, L.. 2013 May. Cationic Antimicrobial Polymers and Their Assemblies. Int J Mol Sci. 2013 May; 14(5): 9906–9946. Published online 2013 May 10. doi: 10.3390/ijms14059906
CTI Reviews. 2017. Organic and Biological Chemistry, 6th Edition. Content Technologies, Inc.