3708 Journal of Applied Sciences Research, 9(6): 3708-3717, 2013 ISSN 1819-544X This is a refereed journal and all articles are professionally screened and reviewed ORIGINAL ARTICLES Corresponding Author: Hesham A. Eissa. Prof. Dr. of Food Technology Department, National Research Centre, 12622 Cairo, Egypt. E-mail: Hamin_essa@yahoo.com. Optimizing Oil Reduction in Fried Eggplant Rings Hesham A. Eissa, Mostafa T. Ramadan, Hatem S. Ali and Gamal H. Ragab Food Technology Department, National Research Centre, 12622 Cairo, Egypt ABSTRACT The effect of thermal pretreatment using water or steam blanching; and chemical pretreatment by soaking in SO 2 , chitosan, carboxy methylcellulose (CMC) or sodium chloride (NaCl) on moisture content, oil uptake, sensory evaluation, colour, electronic structure and frying quality of eggplant rings were investigated. Eggplant rings were blanched for 3min in water and steam, and soaked in 2% chitosan and CMC, 4% NaCl and 0.1% SO 2 solutions (25 o C) previous to frying, to study the effect on oil uptake, moisture content, colour and structure using electronic microscope. Sensory responses indicated the best texture and lowest oil uptake at 4% NaCl solution for 20 min. Soaking had no effect (P<0.05) on color (L*, a* and b*) or moisture and oil loss during deep frying at 180 o C for 4min. Sensory acceptability was not different (P<0.05) between the soaked product and a thermal sample. Frying eggplant rings at 180°C for 4 min was able to optimize the quality of eggplant rings regarding to L*, a*, C*, BI, ΔE-values and non-enzymatic browning (A420 nm).The oil uptake effect of various thermal and chemical pretreatments on eggplant rings was found to decrease in the following order water blanching > coated CMC > steam blanching > coated chitosan > SO 2 > sodium chloride > untreated samples. The fried pre-treated eggplant rings with coated CMC and water blanching gave lower moisture (2.19) and oil (7) content (% on dry matter) compared to other pre-treated samples. It is evident that fried eggplant rings after chemical (chitosan, CMC, salt and So 2 ) and thermal treatments (steam and water blanching) contained numerous types of cellular fragments using electron microscopy. These results indicate that coating CMC and water blanching exhibited oil barrier properties and did not significantly affect the flavor of the product, irregardless of breading type, thus making it a promising alternative in lowering oil content of fried foods. Key words: Eggplant; Rings; Steam; Chitosan; CMC; SO 2 , Colour, Water content, Oil uptake, Frying, electronic microscope. Introduction Eggplant (Solunum melongena L.) is a plant of the family Solanaceae (also known as the nightshades) and genus Solanum. It bears a fruit of the same name, commonly used in cooking and frying. The fruit is capable of absorbing large amounts of frying oil. Production of eggplant is highly concentrated, with 85% of output coming for five countries. China is the top producer (56% of world output) and India is second (26%); Egypt, Turkey and Indonesia produce the remains amount. Its World production is around 32 million tons (FAOSTAT, 2009). Poor diet and/or unhealthy lifestyles contribute to various chronic health conditions that negatively affect the quality of life. Three of the top ten leading causes of death are diet-related, including coronary heart disease (contributes 21.1% of all deaths), cancer (23.4% of deaths), stroke (6.7% of deaths), and diabetes mellitus (2.5% of deaths) according to Singh (1996). All these complications are highly correlated to fat intake (Gebhardt, et al., 2006). Fried foods contain significant amounts of fats, reaching in some cases up to a third of the total food product by weight (Mellema, 2003). Consumers increasingly are aware of the need to lower their daily fat intake. Despite the trend towards lower fat foods, health problems related to high fat intake are still on the rise. This is probably due to the increasing trend to patronize fast food restaurantsm, where deep-fat frying is one of the most popular methods of cooking. In addition to frequent visits to fast food outlets and restaurants, the consumption of snack foods which include deep fried foods, is high (Kuchler et al., 2004). Deep-fat frying is a widely used food process which consists basically of immersion of food pieces in hot vegetable oil. The high temperature causes partial evaporation of the water, which moves away from the food and through the surrounding oil, and a certain amount of oil is absorbed by the food. Frying is often selected as a method for creating unique flavors and texture in processed foods that improve their overall palatability. Frying temperatures can range from 130 °C to 190 °C, but the most common temperatures are 170–190 °C. The high temperature of the frying fat typically leads to the appreciated surface color and mechanical characteristics of fried foods, and besides, heating of reducing sugars affects a complex group of reactions, termed caramelization,