الفهرس 
Deep-fat fryingOnly 14 pages are availabe for public view
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Abstract
It is estimated that some 20 million tonnes of oils and fats are used for frying around the world, with industrial frying the major user of frying oil. Industrial frying oil requires oils and fats of good quality and nutritive value. corn oil meets these requirements as it has no unpleasant room odor, a high resistance to oxidation and high content of nutrients from its fatty acid composition, and does not polymerize easily. Frying, cooking technique has been used for centuries that originated in ancient Egypt around 2500BC. It was simpler frying than today, most close to roasting. Frying was conducted in a kettle of oil heated on a stove or over an open fire. Small batches of food are immersed in hot oil and removed when fried as determined by the experience of the cook and by the time frying technique turns to be a big introduction of continuous cookers. No doubt that technological development of fryers is followed with commercial development of frying. Today, fried foods are the most favorites for people around the world and qualities factors such as flavor, texture, shelf life and nutritional attributes of frying fat had to be reconsider able in the final fried product. Many physical and chemical changes have been occurred in frying oil that may adversely affect nutritional value and sanitation of foods. Generally, these changes include three chemical reactions that may occur simultaneously: hydrolysis, polymerization and oxidation, which produce a great number of potential toxic decomposition products deposit on the surface of the fryer and adsorbed by the food. Also, many authors have been paid more attention towards the formation and/or contamination of cooking oils with carcinogenic compounds. By-products coming from oil degradation during frying and cooking could be induced some toxic and/or carcinogenic effects have been recorded several years ago. These harmful effects restricted the use of recycled cooking oils in formulated feed for animal production because they poses some risks for animal health and, as a consequence of bioaccumulation, for consumer health Therefore, many trials have been done relating to the cooking oil recycling process but the field of technology for the purification of cooking oils is not well developed, and the work that has been carried out has not been adequately coordinated with commercial interests and the interests of society or the administration, which aim to improve consumer safety. Basically, the simplest purification systems consist of agitating waste cooking oils with water and then decanting and/or centrifuging. This very simple procedure may be highly effective for eliminating a large proportion of the water which accompanies these oils, and also for eliminating solid particles or impurities from the fried foods. However, it obviously does not permit proper purification of the oil, as the oil degradation compounds and liposoluble contaminants are retained in the recovered (recycled) oil. Adding of antioxidants in oils and fats to prevent oxidative rancidity, and the safety of antioxidant substances is considered Although many authors using some of these compounds as antioxidants in oils and fats but it is still needs more and more research to study their different mechanism of action as well as the safety of using for human health. Another technology, bioremoval of toxic substances from edible oils as affected by deep-fat frying process was developed. Waste water samples from Oil and Soap Company was used as a source of oil using bacteria and very simple technique for treatment the deep-fat frying oils with bacterial isolates was applied. Although, these resulted purified used deep all of -fat frying oil samples have been evaluated from physical and chemical point of view the toxicological aspects are still in debate. Therefore, the present study aims to evaluate the used deep-fat frying oil samples which have been treated with different purification techniques from a toxicological point of view. The results of this study could be opened new avenue in the field of food toxicology through establish effective and cheep purification system for the used deep-fat oils and adequately coordinated with commercial and/or consumer interests. The obtained results could be summarized as follow: I. Fat constants of corn oil subjected to deep-fat frying process for 12h and different washing treatments. Acid value: The AV of deep-fat frying oil of potato was recorded 0.501 mg KOH/g. After first washing with different treatments this value was decreased by different rates ranged 21.95- 52.70%. These rates were increased with the replication of all washing treatments. After the third washing with different treatments the rates of decreasing were recorded 31.93-62.68%. The adding of some antioxidants i.e. (α-tocopherol and coumaric acid) to the distilled water increased the rate of AV decreasing as the result of washing. Peroxide value: The PV of deep-fat frying oil of potato was recorded 16.01 meq/kg. After first washing with different treatments this value was decreased by different rates ranged 37.04- 49.34%. These rates were increased with the replication of all washing treatments. After the third washing with different treatments the rates of decreasing were recorded 39.16-54.97%. The adding of some antioxidants i.e. (α- tocopherol and coumaric acid) to the distilled water increased the rate of PV decreasing as the result of washing. Malonaldehyde content: The MDA of deep-fat frying oil of potato was recorded 9.077 mg/kg. After first washing with different treatments this value was decreased by different rates ranged 25.93-51.07%. These rates were increased with the replication of all washing treatments. After the third washing with different treatments the rates of decreasing were recorded 34.87-59.11%. The adding of some antioxidants i.e. (α- tocopherol and coumaric acid) to the distilled water increased the rate of MDA decreasing as the result of washing. II. Bacterial removal of the toxic compounds from corn oil subjected to deep-fat frying process for 12 h The BaP content of deep-fat frying oil of potato was recorded 1.435 μg/g. After treated with bacterial isolates (10 % oil concentration in medium) at different incubation time i.e. 24, 48, 72 and 96 h this value was decreased by the rates 15.12, 24.11, 32.06 and 30.31%, respectively. These rates were increased with the increasing of oil concentration in medium. When the oil concentration was 15 % the rates of decreasing were 22.65, 29.55, 38.68 and 37.21%, respectively. Therefore, the rate of decreasing in BP was increased with the elongation of incubation time until 96 h. The same behavior was relatively observed for the other toxic compound i.e. MDA. III. Studying the potential adverse effect of used deep-fat frying corn oils treated with different purification process towards liver homogenate of karmoot fish Catfish liver cells homogenate were used as an experimental tool for studying the potential toxic effects of used deep-fat frying corn oils treated with different purification process. For NR assay which determined the lysosomes activity of liver cells, the data were standardized by expressing absorbance data in the presence of each technical process as a percentage of that in the control medium. The absorbance measurements of this assay (as % of control) were ranged 0.408-1.051, 0.595- 1.067, 0.533-1.046, 0.695-1.073, 0.669-1.073 and 0.571-1.153 % for TW, DW, DW+α-tocopherol, DW+coumaric acid and microbiology (microbial isolates), respectively. The higher adverse cytotoxic effect (lysosomal dysfunction) was recorded for the control samples. Treating of the deep-fat frying corn oils (control stamples) with different purification process leads to decrease in the adverse cytotoxic effect by different rates. The higher effect was observed by the DW+α- tocopherol process followed by DW+coumaric acid, microbiology (microbial isolates), TW and DW, respectively. For MTT assay which determined the mitochondrial activity of liver cells, the absorbance measurements of this assay (as % of control) were ranged 0.389-1.036, 0.510-1.049, 0.499-1.045, 0.686-1.069, 0.647- 1.067 and 0.545-1.179 % for TW, DW, DW+α-tocopherol, DW+coumaric acid and microbiology (microbial isolates), respectively. The higher adverse cytotoxic effect (mitochondrial dysfunction) was recorded for the control samples. Treating of the deep-fat frying corn oils (control stamples) with different purification process leads to decrease in the adverse cytotoxic effect by different rates. The higher effect was observed by the DW+α-tocopherol process followed by DW+coumaric acid, microbiology (microbial isolates), TW and DW, respectively. For CV assay which determined the cell wall membrane integrity of liver cells, the absorbance measurements of this assay (as % of control) were ranged 0.464-1.058, 0.629-1.062, 0.577-1.062, 0.851- 1.076, 0.727-1.056 and 0.601-1.125% for TW, DW, DW+α-tocopherol, DW+coumaric acid and microbiology (microbial isolates), respectively. The higher adverse cytotoxic effect (cell wall integrity) was recorded for the control samples. Treating of the deep-fat frying corn oils (control stamples) with different purification process leads to decrease in the adverse cytotoxic effect by different rates. The higher effect was observed by the DW+α-tocopherol process followed by DW+coumaric acid, TW, microbiology (microbial isolates) and DW, respectively. On the other side, the concentrations of used deep-fat frying corn oil treated with different purification process causing initial values, the concentration of oils that caused 10% decrease in absorbance (NR90, MTT90, and CV90 ) and midpoint values, the concentration of oil that caused 50% decrease in absorbance (NR50, MTT50, and CV50 ), as compared to control values, for each cytotoxicity test varied with the specific assay. In NR, MTT and CV the midpoint toxicities were not recorded values (out of curve dimensions) for all the tested oil samples treatments except DW. According to these data, the sequence of purification treatments effectiveness for the different cytotoxicity assays were DW+α-tocopherol DW+coumaric acid TW microbiology (microbial isolates) DW treatments.