Oxidation kinetics of hazelnut oil treated with ozone

Abstract

SUMMARY:The present study investigates the oxidation kinetics of hazelnut oil ozonated in different treatment periods (1, 5, 60 and 180 min). The kinetic rate constant (k) was taken as the inverse of oxidation onset time (T o ) observing a linear relationship from the plot of lnT o to isothermal temperatures (373, 383, 393, and 403 K) carried out at differential scanning calorimetry. Kinetic parameters, activation energy (E a ), activation enthalpy (ΔH ‡ ) and entropy (ΔS ‡ ) were calculated based on the Arrhenius equation and activated complex theory. k values showed an exponential rise with the increase of ozone treatment time. The increase in k correlated well with the increase in the peroxide and free fatty acid values of all samples. E a and ΔH ‡ of the ozone treated oils showed a reducing trend and reflected an increased oxidation sensitivity after ozone treatment. Consistently, an increase in ΔS ‡ indicated a faster oxidation reaction with an increase in ozone exposure time. However, no significant difference was observed in k, E a , ΔH ‡ , ΔS ‡ (p < 0.05) as a function of storage period, after the hazelnut oil was treated with ozone for 1 min. KEYWORDS: DSC; Hazelnut oil; Kinetics of oxidation; OzoneRESUMEN: Cinética de oxidación del aceite de avellana tratado con ozono. El presente estudio investiga la ciné-tica de oxidación del aceite de avellana ozonizado durante diferentes períodos (1, 5, 60 y 180 min). La constante de velocidad cinética (k) se tomó como la inversa del tiempo de inicio de la oxidación (To) observando una relación lineal cuando se representa el lnTo con las temperaturas isotérmicas (373, 383, 393 y 403 K) llevadas a cabo en calorimetría de barrido diferencial. Los parámetros cinéticos, energía de activación (Ea), entalpía de activación (ΔH ‡ ) y entropía (ΔS ‡ ) se calcularon sobre la base de la ecuación de Arrhenius y de la teoría compleja activada. Los valores de k mostraron un aumento exponencial con el aumento del tiempo de tratamiento de ozono. El aumento de k se correlacionó bien con el aumento de peróxidos y de los ácidos grasos libres de todas las muestras. Ea y ΔH ‡ de los aceites tratados con ozono mostraron una tendencia reductora que refleja una mayor sensibilidad a la oxidación de los aceites después del tratamiento con ozono. Consistentemente, un aumento de ΔS ‡ indicó una reacción de oxidación más rápida con un aumento del tiempo de exposición al ozono. Sin embargo, no se observó diferencia significativa en k, Ea, ΔH ‡ , ΔS ‡ (p <0.05) en función del período de almacenamiento, después de que el aceite de avellana fue tratado con ozono durante 1 min.

Quality attributes of oil extracted from hazelnuts treated with gaseous ozone

“…The results with respect to PV are in accordance with the observations of other authors for ozonated pistachios and whole wheat flour (Babaee et al, 2022). Ozone treatment was observed to increase the PV of hazelnut oil samples exponentially, according to Uzun and Ibanoglu (2017). Additionally, Chen et al (2014) and de Oliveria et al (2020) observed an increase in the peroxide index of oils extracted from ozonized peanuts and Brazil nuts, respectively.…”

Evaluation of different ozonation on aflatoxin degradation and physicochemical characteristics of hazelnuts

“…The PV of hazelnut are used as an indicator of the level to which F I G U R E 1 Effect of ozonation on the degradation of aflatoxin B1 and total aflatoxins in hazelnut kernels oxidative rancidity reactions reached during ozonation. Hazelnut is rich in monounsaturated (MUFA) and polyunsaturated (PUFA) (approximately 83% MUFA and 9% PUFA) fatty acids even though it has been reported to have high oxidative stability due to its high α-tocopherol content (Uzun & Ibanoglu, 2017).…”

Continuous Stirred Tank Reactor: A Process Design for Interesterification of Macauba (Acrocomia aculeata) palm oil

“…The activation energy (E a ) of 105000.3 J mol −1 and the rate constant (k) of 2.6 × 10 −4 min −1 were estimated by nonlinear regression, also considering the Arrhenius law. The enthalpy of activation (∆H) of 9.81 x 104 J kg −1 was obtained by linear regression, according to the activation complex theory (Uzun & Ibanoglu, 2018). The parameters were then applied to the continuous version of the kinetic treatment, as seen in Table 1 of the following item 2.5.…”