Calin Jianu

Synthesis of nonionic-anionic colloidal systems based on alkaline and ammonium β-nonylphenol polyethyleneoxy (n = 3-20) propionates/dodecylbenzenesulfonates with prospects for food hygiene

BackgroundThe main objective of this work was to obtain a binary system of surface-active components (nonionic soap – alkaline and/or ammonium dodecylbenzenesulfonate) with potential competences in food hygiene, by accessing a scheme of classical reactions (cyanoethylation, total acid hydrolysis and stoichiometric neutralization with inorganic alkaline and/or organic ammonium bases) adapted to heterogeneously polyethoxylated nonylphenols (n = 3-20). In the processing system mentioned, dodecylbenzenesulfonic acid, initially the acid catalyst for the exhaustive hydrolysis of β-nonylphenolpolyethyleneoxy (n = 3-20) propionitriles, becomes together with the nonionic soap formed the second surface-active component of the binary system.ResultsIn the reaction scheme adopted the influence of the main operating (duration, temperature, molar ratio of reagents) and structural parameters (degree of oligomerization of the polyoxyethylene chain) on the processing yields for the synthetic steps was followed. The favorable role of the polyoxyethylene chain size is remarked, through its specific conformation and its alkaline cations sequestration competences on the yields of cyanoethylation, but also the beneficial influence of phase-transfer catalysts in the total acid hydrolysis step. The chemical stability of dodecylbenzenesulfonic acid (DBSH) at the temperature and strongly acidic pH of the reaction environment is confirmed. The controlled change of the amount of DBSH in the final binary system will later confer it potential colloidal competences in food hygiene receipts.ConclusionsThe preliminary synthetic tests performed confirmed the prospect of obtaining a broad range of useful colloidal competences in various food hygiene scenarios.

Airborne particulate contaminants during refrigeration of meat in controled medium.

The transfer of contamination through the airborne route is one of the most significant areas of high-care food production. The food industry specially the manufacturing of the chilled meat products strive for lower levels of the air contamination, therefore lot of experimental and numerical studies considers the concentration of airborne particulate contaminants, such as different species of food spoilage microorganism. In a food processing system concerned with efficient and duration preservation of primary agricultural produce post-harvesting/post-slaughtering, low carbonylic compounds as potential volatile metabolites generated by the micro flora present in the modified atmosphere CO2/O2; N2/O2, etc. of refrigeration areas for wholesale or pre-packaged fresh meat are of major interest together with other risk factors of consumer food safety. Some low aliphatic ketones with high volatility can be seized by smelling even at freezing temperatures in an advanced stage of accumulation. In this paper we suggest a guick method for the measurement of their concentration expressed as MEK starting with values of 1 ?g/m3 atmosphere (refrigeration environment) through periodical and/or continuous sampling through aspiration from the proximity of meat surface both pre-packed and stored in standard cells in modified atmosphere (25% CO2; 75% O2) (25% N2; 75% O2) in an ethanol solution of salicylaldehyde 10% (CAS 90-02-8) when it makes up a colorimetrable yellow-orange compound. Assessment can be done continuously in parallel with comparing the colour with a potassium dichromate scale (qualitatively) and also by reporting it to a sampling curve previously prepared (quantitatively). The specificity of the method is affected only by the presence in the refrigeration atmosphere of other toxic volatile metabolites of ketonic nature (acetone, acetoin, 2,3-butane dione).