Antioxidant activity of the lipophilizated phenolic compound added to an emulsion containing omega 3 fatty acids and phytosterols

• Grant number: 12/14193-2
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: January 01, 2013
• End date: April 30, 2013
• Field of knowledge: Agronomical Sciences - Food Science and Technology - Food Science
• Principal Investigator: Inar Castro Erger
• Grantee: Patrícia Borges Botelho Gamba
• Host Institution: Faculdade de Ciências Farmacêuticas (FCF). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

Omega 3 fatty acids and phytosterols can be combined to formulate food functional emulsions aimed at reducing triacylglycerols and cholesterol respectively, promoting the reduction of cardiovascular disease risk. However, these two bioactive compounds are highly susceptible to oxidation during their incorporation into a food emulsion and also during its shelf life, even when stored at low temperatures. The products formed by omega 3 fatty acids and phytosterols oxidation, in addition to annulling the beneficial functional effects, can also become toxic for animals and humans. One strategy used to overcome this limitation is the addition of compounds with antioxidant action that will be oxidized in place of the bioactive compounds. These antioxidants can be artificial or natural, with the artificial materials being more effective than the natural ones but potentially mutagenic, depending on the dosage. The antioxidant activity of these compounds depends of their capacity to donate electron or hydrogen to the reactive species and their localization in the emulsioned system. Phenolic compounds are natural antioxidants characterized by a hydrophilic behavior. According to the "Polar Paradox", hydrophilic molecules present a worse antioxidant performance in emulsions due to their lower affinity to the interface, where the oxidation rate is higher. Lipophilization is a technique that adds an apolar chain to the phenolic structure reducing the polarity of the original molecule. However, this structural change can also reduce the antioxidant activity due to the involvement of the hydroxyl radical in the chemical or enzymatic reaction. Thus, our hypothesis is that the lipophilization will improve the antioxidant activity of the phenolic compounds when added to emulsions, due to the strong effect of polarity usually observed in these systems. In order to evaluate this hypothesis three assays will be carried out. Firstly, eleven natural phenolic compounds will be applied in three different emulsions models aiming to evaluate their antioxidant behavior when they are applied alone, with other antioxidants naturally present in the oils and also in presence of milk proteins. After, in the second step, one compound will be selected and submitted to the lipophilization process. The oxidative stability of an emulsion containing the phenolic compound pure and lipophilizated will be evaluate by measuring the primary and secondary products of the oil oxidation. Finally, the best result observed in the second step will be applied to prepare a milk functional emulsion containing omega 3 fatty acids and phytosterols. The same chemical markers added of sensory analysis will be performed to evaluate the oxidative stability of this milk functional emulsion. (AU)