Romanian Biotechnological Letters Vol. 16, No. 5, 2011 Copyright © 2011 University of Bucharest Printed in Romania. All rights reserved REVIEW 6467 Nutritional and health aspects related to frying (II) Received for publication, January 5, 2011 Accepted, September 1, 2011 MIHAELA GHIDURUS 1* , MIRA TURTOI 1 , GEORGE BOSKOU 2 , PETRU NICULITA 1 , VASILICA STAN 3 1 University of Agronomical Sciences and Veterinary Medicine Bucharest, Faculty of Biotechnology, Marasti Blv 59,011464, Bucharest, Romania 2 Harokopio University of Athens, Department of the Science of Dietetics - Nutrition, 70 El. Venizelou av., Kallithea, 17671, Athens, Greece 3 University of Agronomical Sciences and Veterinary Medicine Bucharest, Faculty of Agronomy, Marasti Blv 59,011464, Bucharest, Romania * mihaela_ghidurus@yahoo.com Abstract Current consumer requirements are directed towards improving the quality of foodstuffs expecting that certain processed foods and the ones prepared by frying will exhibit in addition to sensorial attributes nutritional qualities as well. Most of the processing and preparation methods of food are based on heat treatment, which also has less desirable effects on food such as: changing in color, taste, flavor and texture. In addition, during heat treatment by frying beside the aroma compounds formed which are very appreciated by consumers also other compounds which are not desirable get accumulated in the products; those compounds are formed by partial or total alteration of thermolabile nutrients present in food and in the frying oil. Tocopherols, essential amino acids, fatty acids present in food are degraded following hydrolysis, oxidation and polymerization reactions, etc. Therefore we are trying to review the nutritional and the risk factors associated to frying. Keywords: food safety, food quality, frying process, oils Introduction There is a growing concern about the nutritional and safety aspects of consuming deteriorated frying fats and oils. Many experiments have been done on rats by feeding them with degrading frying oils [21]. It is well established that the heating of fats can result in the formation of compounds with non-nutritional properties. Compounds formed may be enzyme inhibitors, vitamin destroyers, lipid oxidation products, gastrointestinal irritants, and /or potential mutagens [10]. Early studies used extremely overheated fats that were toxic if fed to animals [5]. High mortality rates were observed in most of the cases. Growth of the liver and an increase in kidney volume were also reported, following the use of degraded oil [21]. Later fats and oils were heated in equipment for deep fat frying under the conditions of good catering practice. Such heated fats showed no detrimental effects even if fed in long-term feeding trials [5]. However, certain fractions of the heated fats, the so-called “Total Polar Compounds”, caused the following clearly noticeable effects in the feeding studies: growth retardation, increased liver and kidney weights, and disorders of the enzyme system but, only if fed in high doses [5]. There are several classes of material in oxidized fat that have toxic effects: peroxidized fatty acids and their subsequent end products, polymeric material and oxidized sterols [1]. The toxic components are: i) Hydroperoxides, ii) Hydroxy fatty acids, iii) Carbonyl compounds, iv) Cyclic monomers, v) Dimers and Polymers, vi) Polycyclic aromatic hydrocarbons, vii) Oxidized sterols [23].