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
Defatted rice bran (DRB) and hydrolyzed defatted rice bran (DRBT) were prepared from rice bran meal (RBM). Proximate composition, oil and water binding capacities, emulsifying and foaming characteristics were determined. Effect of different substitution of DRB and DRBT as Fat replacers in biscuit on the farenograph parameters and sensory characteristics were also evaluated. The total protein, ash and crude fiber were significantly (P≤0.05) increased in each of DRB and DRBT compared to RBM. Defatted rice bran protein hydrolyzed improved the DRBT water, oil absorption index being 1.7. Used each of DRB or DRBT gave high emulsifying activity and stability indices in casein model system. The same trend was observed with foam activity and stability indices in egg albumin system. farenogram parameters significant (P≤0.05) affected by using DRB and DRBT. The prepared biscuits samples had high sensory scores with 10 to 50 % DRB and DRBT attributes and recorded non-significant (P≤0.05) differences compared to control sample.
The influence of extraction systems (press, two-and three-phases) on the quality of olive oils extracted from two olive oil varieties (Coratina and Koronakii) was studied. Refractive index (RI), free acidity, peroxide value, specific coefficients of extinctions (K232, K270 and ΔK), natural antioxidant content, fatty acids composition, oxidative stability and antioxidant activity were determined as well as sensory analysis was done. From the obtained results, it could be noticed that there were no significant differences among olive varieties and extraction techniques in view of oils values; refractive index and unsaponifiable matters which appeared to be approximately the same. Also, results observed that there were slight differences in fatty acids composition, depending on the extraction technique and varieties employed. While, revealed that the extraction systems had significant effect on most chemical characteristics and oxidative stability of oils due to the differences in their natural antioxidants content which was higher in oils extracted by the two-phases and press systems than in that extracted by three-phase system. The sensory evaluation and the overall quality index indicated that olive oil obtained by two-phase system was the preferable among other oils obtained by press and three-phases; it received significantly the highest scores in all the judged quality attributes. Also, the total polyphenols were higher in the extra virgin olive oils obtained by the two-phase and press systems than in that obtained by threephase system because the former two systems do not require the addition of water to olive paste in the decanter whilst, in the three-phases system water must be added to olive paste. The data revealed that the best extraction system was the twophases system which produced high quality olive oil with high content of total polyphenols and that made it more resistant for oxidation during storage. Results also showed that Coratina variety gave oil with higher resistant to oxidation and higher sensorial score than oil extracted from Koronakii variety.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.