Oxidation at intermediate moisture contents

Abstract

In the study of the oxidation rate of methyl linoleate in protein and cellulose systems, a prooxidant effect was found at intermediate moisture contents. At lowwater content, water hydrates metals and hydrogen bonds with peroxides, and an overall decrease in the rate of lipid oxidation results. With an increase in the water content to the region with a water activity of 0.6 to 0.7, the water predominantly acts as a solvent to dissolve and mobilize previously unavailable trace metals with the result of increased oxidation rates. Use of chelating agents such as ethylenediaminetetraacetic acid and citric acid reduced oxidation significantly although some antioxidant activity was also observed for butylated hydroxyanisole. These results have important implications in the preparation of intermediate moisture foods. INTRODUCTI ON

Stability of Unsaturated Methyl Esters of Fatty Acids on Surfaces.

“…It is possible that moisture content of the silica gel as well as its surface had an effect on the stability of the esters. This was demonstrated with methyl linoleate on cellulose (17,18) where oxidation was markedly reduced by humidification. Water has clearly been shown to increase the binding of some compounds to silica gel (13).…”

Ação antioxidante de especiarias face diferentes atividades de água

“…Os efeitos da Aw sobre a oxidação dos lipídios, segundo HEILDELBAUGH, KAREL [9] e HURTADO [11], são irregulares: favorecendo-a ou reduzindo-a. Estes efeitos anômalos, segundo LABUZA et al [16] parecem, também, ter importância em termos de ação antioxidante.…”

“…Os efeitos da Aw sobre a oxidação dos lipídios, segundo HEILDELBAUGH, KAREL [9] e HURTADO [11], são irregulares: favorecendo-a ou reduzindo-a. Estes efeitos anômalos, segundo LABUZA et al [16] parecem, também, ter importância em termos de ação antioxidante.Assim, visando oferecer alguma contribuição para a estabilização de alimentos lipídicos, foi implementada esta pesquisa para avaliar o efeito antioxidante de algumas especiarias associado ao efeito físico-químico ou atividade da água, presente no sistema, na tentativa de encontrar nessas substâncias de uso tradicional, combinações úteis de compostos antioxidantes. …”

Desarrollo Y Caracterización De Polímeros Activos Hidrofílicos Para El Envasado De Alimentos

“…The oxidation of the control sample did not increase markedly after the third day, and after five days peroxide concentration started to decrease till the end of the experiment, as a result of peroxide degradation due to secondary oxidation reactions (Labuza et al, 1971). The oxidation process was very fast owing to: i) sardines with highly unsaturated fat, because of the season (Beltran & Moral, 1990); ii) salted process may induce prooxidation (Aubourg & Ugliano, 2002;Guillén & Ruiz, 2004).…”