Hamed Hosseini; Mohammad Ghorbani; Alireza Sadeghi Mahoonak; Yahya Maghsoudlou
Abstract
An accelerated shelf-life test using elevated temperatures 62, 72 and 82 ˚C was conducted to predict the oxidation progression of walnuts over a long-term storage. Oxidation parameters including values of conjugated dienes (CD) and trienes (CT) values and thiobarbituric acid (TBA) value were employed ...
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An accelerated shelf-life test using elevated temperatures 62, 72 and 82 ˚C was conducted to predict the oxidation progression of walnuts over a long-term storage. Oxidation parameters including values of conjugated dienes (CD) and trienes (CT) values and thiobarbituric acid (TBA) value were employed to evaluate the oxidation processes. Changes followed an apparent first-order kinetic. Walnuts and walnut kernels were also kept in normal condition (20-30˚С; RH, 35-45%) for 12 months in order to validate the approach. A maximum of energy (62.24-75.67 kJ mol-1 K-1) needed for formation of primary oxidation products and a minimum of energy (35.65 kJ mol-1 K-1) to generate secondary oxidation products were calculated. Formation of oxidation products in walnut kernels was found to be a temperature-dependent reaction, with Q10 =1.44- 2.1. The results showed that CD and CT values could provide a proper estimation for oxidative stability of the nuts stored in ordinary condition, with an average error of approximately 12.9%.
Hamed Hosseini; Mohammad Ghorbani; Alireza Sadeghi Mahoonak; Yahya Maghsoudlou
Abstract
Oxidative stability of walnut (Juglansregia L.) was evaluated over a period of 1 year storage in various conditions. The whole walnuts, walnut kernels, walnut chopped kernels, walnut kernels packaged in polyethylene (PET) under vacuum and poly propylene (PP) contain of CO2 were kept in a normal condition ...
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Oxidative stability of walnut (Juglansregia L.) was evaluated over a period of 1 year storage in various conditions. The whole walnuts, walnut kernels, walnut chopped kernels, walnut kernels packaged in polyethylene (PET) under vacuum and poly propylene (PP) contain of CO2 were kept in a normal condition (temperature, 19-30˚С and relative humidity (RH), 35-45%). The whole walnuts and walnut kernels were also kept in refrigerator (4˚С, RH 75%). Some quality parameters for the oil extracted from walnut kernels were measured throughout the storage. Peroxide value of whole walnuts, walnut kernels and walnut chopped kernels pass over 2 meq O2/kg after 12, 10 and 8 months storage, respectively. Peroxide value of the packaged nuts and the nuts stored at cold storage were increased only 1 meq O2/kg over a period of 1 year storage. According to the statistically analysis results, the effect of storage condition and storage time on oxidative stability of walnuts were significant (p walnuts shell > contact surface of walnut kernels with environment were defined to maintain the quality of walnut kernels during long term storage.
