Oxidative stability is one of the most important indicators for maintaining the quality of edible oils. 1 H NMR fingerprinting is used to evaluate the stability of edible oils at room temperature. The assignments of the 1 H NMR signals of the major and minor components of unoxidized edible oils and the oil stability prediction were given. Minor components of the oils are playing an essential role in defining oil authenticity and quality. Extra virgin olive oil (EVOO) showed b-sitosterol, whereas, moringa oil (MO) showed b-sitosterol and stigmasterol. MO showed nonglyceride fraction, aliphatic chains and olefins. Sunflower oil (SO) could be easily distinguished due to its high linoleic acid content followed by apricot kernel oil (AKO). The order of stability of edible oils under study was: MO > EVOO > AKO > SO. 1 H NMR spectral data agreed with the results obtained from Rancimat method for the determination of oxidative stability of edible oils under study. The main advantages of this method are the short time of analysis, the possibility to analyze samples without any preliminary treatment, and the small quantity of sample required.ª 2014 Production and hosting by Elsevier B.V. on behalf

COMPARATIVE study was carried out to evaluate and compare the oxidative 12345 stability of vegetable oils (olive, corn and sunflower) in Egypt, through evaluation of accelerated oxidation at four different isothermal temperatures (110, 120, 130, 140 °C) using two different instruments: a differential scanning calorimeter (DSC) and a Rancimat instrument, taking into account the physicochemical quality characteristics and relationships between oxidative stability and fatty acid composition of oils. The Rancimat instrument was set at the four different isothermal temperatures with an air flow 20 L/h and measures the induction period (IP) of the selected oils. The differential scanning calorimetry (DSC) technique involved accelerated oxidation of oil samples in an air flow of 60 ml/min in DSC cell set at four different isothermal temperatures. A rapid increase in evolved heat was observed with the appearance of a sharp exothermic curve during initiation of the oxidation reaction. From the resulting exothermic curve, the onset of oxidation time (To) was determined graphically by the DSC instrument. There was an excellent correlation (p<0.0001) found between DSC (T0) values and Rancimat (IP) measurements where the Pearson correlation coefficient (>0.98) between the two methods with coefficient of determination (R 2 >0.89) for DSC independent of the vegetable oil source, imply that DSC can be recommended as an alternative appropriate objective method for assessing the oxidative stability of vegetable oils because of its simplicity, absence of toxic chemicals, small amount of sample and time-saving nature and could be easily used for routine analysis in oils and fats industry.

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Functional biscuits are considered energetic dietary supplements for children suffering from malnutrition and micronutrient deficiency. Biscuits stuffed with date paste and fortified with minerals and vitamins have a considerable fat content where lipid oxidation processes may occur with improper packing which affects the quality and safety of biscuits leading to their contamination with pathogenic microorganisms and toxic chemicals. Therefore, the current study aimed to investigate the oxidative stability of fats in date biscuits and their shelf life under different types of packing materials ranging from sealed translucent polypropylene (PP), and sealed metalized polypropylene (MPP), compared with the control unsealed translucent polyethylene (PE) bags. Physicochemical, microbiological, storage and sensory evaluations for biscuits samples under the different packing materials along with the chemical migration test for the packing materials were carried out. Results showed significant differences (P < 0.05) among samples with increasing acidity, peroxide value, diene, and triene, whereas, the iodine value and oxidative stability decreased with storage periods. Fatty acid composition showed slight changes with a decrease in unsaturated fatty acids (ΣUSFA) due to the lipid oxidation processes with the emergence of trans-fatty acids after 90 days of storage with the emergence of microbiological activity expressed in a considerable increase in the aerobic plate count (APC) and total combined yeasts and molds count (TYMC) in the control sample (PE) compared with PP and MPP with the superiority of MPP as the best packing material for maintaining the best quality and safety of biscuits with lowest lipid oxidation and highest shelf life.

This review is designed to be a comprehensive review in a new way to help you to understand the principle and theory of Thermal Analysis with special emphasis on Differential Scanning Calorimetry (DSC) as a new fast-growing and important technique used for authentication, characterization and detecting adulterations of oils and fats. DSC is a powerful instrument that measures the energy absorbed or released as a function of time or a controlled temperature profile. The sensor of the DSC is the heat flux plate which is designed to give superior performance and rugged reliability. The heat flux plate is capable of measuring small energy changes over the entire temperature range. Examples of measurements with DSC are Oxidative Stability, Melting Enthalpy, Glass Transition, Heat of Crystallization, Purity Determination and Heat Capacity. DSC can be used as a rapid method for assessment of oxidative stability, prediction of shelf life and evaluation of the quality of edible oils during refining. DSC holds a potential to be used as the reliable and reproducible technique for the detection of adulteration of animal body fat added in ghee individually and in combination of vegetable oil. DSC method is faster, require less sample size and no chemicals or solvents compared to other conventional, modern oxidative stability methods and conventional shelf life estimation.