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Frying Time (frying + time)
Selected AbstractsFormation and distribution of oxidized fatty acids during deep- and pan-frying of potatoesEUROPEAN JOURNAL OF LIPID SCIENCE AND TECHNOLOGY, Issue 11 2007Nick Kalogeropoulos Abstract The formation of cis- 9,10-epoxystearate, trans- 9,10-epoxystearate, cis -9,10-epoxyoleate, cis -12,13-epoxyoleate, trans -9,10-epoxyoleate, trans -12,13-epoxyoleate and the co-eluting 9- and 10-ketostearates during eight successive pan- and deep-frying sessions of pre-fried potatoes in five different types of vegetable oils , namely cottonseed oil, sunflower oil, vegetable shortening, palm oil and virgin olive oil , was followed and quantified both in fried oils and in fried potatoes by GC/MS after derivatization to methyl esters. These oxidized fatty acids were present at relatively low concentrations in the fresh oils and pre-fried potatoes while they increased linearly with frying time, reaching up to 1140.8,µg/g in virgin olive oil (VOO) and 186.9,µg/g in potatoes pan-fried in VOO after eight pan-frying sessions, with trans -9,10-epoxystearate predominating in all cases. The formation of polymerized triacylglycerols (PTG) was also quantified in frying oils by size exclusion HPLC. Pan-frying caused higher oxidized fatty acid and PTG formation compared to deep-frying. Epoxyoleates and PTG concentrations were increased after frying in polyunsaturated oils, while epoxystearate and 9- and 10-ketostearate concentrations were increased after frying in monounsaturated oils. No specific absorption of the oxidized fatty acids by the fried potatoes seems to occur. The dietary intake of oxidized fatty acids and PTG by the consumption of fried potatoes was discussed. [source] The optimization of vacuum frying to dehydrate carrot chipsINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 9 2005Liu-ping Fan Summary The effects of pretreatment and processing conditions, such as frying temperature, absolute vacuum pressure and frying time; on the properties of fried carrot chips were studied. Statistical analysis with response surface regression showed that moisture content, fat content and breaking force of carrot chips were significantly (P < 0.05) correlated with frying temperature, vacuum absolute pressure and frying time. The optimum conditions were a vacuum frying temperature of 100,110 °C, a vacuum absolute pressure of 0.010,0.020 MPa and a frying time of 15 min. [source] OPTIMIZATION OF PRE-FRY DRYING OF YAM SLICES USING RESPONSE SURFACE METHODOLOGYJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2010OLAJIDE PHILIP SOBUKOLA ABSTRACT The effect of convective hot-air drying pretreatment and frying time at a frying temperature of 170 ± 1C on moisture and oil contents, breaking force (crispness) and color parameters of yam chips was investigated. Response surface methodology technique was used to develop models for the responses as a result of variation in levels of drying temperature (60,80C), drying time (1,5°min) and frying time (2,6°min). Drying pretreatment had a significant effect on oil and moisture contents, breaking force and color parameters of yam chips, with water removal exhibiting a typical drying profile. Response surface regression analysis shows that responses were significantly (P < 0.05) correlated with drying temperature and time and frying time. The optimum pre-fry drying condition observed was a drying temperature of 70,75C for about 3,4 min while frying for 4,5 min. PRACTICAL APPLICATIONS Deep-fat frying is a very important cooking method and a lot of effort has been devoted to manufacturing fried products with lower oil content and acceptable quality parameters. The information provided in this work will be very useful in manufacturing fried yam chips of acceptable quality attributes through the combination of drying pretreatment conditions. The result is very useful in considering different processing variables and responses at the same time as compared with single factor experiment common in the literature. [source] KINETICS of QUALITY CHANGE DURING COOKING and FRYING of POTATOES: PART I. TEXTUREJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2003F. NOURIAN ABSTRACT Kinetics of texture change during cooking and frying of potatoes were evaluated in this study. Potatoes were cut into cylinders (diameter × height: 20 mm × 20 mm for cooking, and 10 mm × 20 mm for frying) and cooked in a temperature controlled water bath at 80,100C or fried in a commercial fryer at 160,190C for selected times. the cooked samples were water cooled while the fried samples were air cooled immediately after the treatment. Test samples were then subjected to a single cycle compression test in a computer interfaced Universal Testing Machine and three textural properties (hardness, stiffness and firmness) were derived from the resulting force-deformation curves. Texture parameters of cooked potatoes decreased with progress of cooking time and the rate of texture changes associated with each temperature was found to be consistent with two pseudo first-order kinetic mechanisms, one more rapid than the other. Textural values of fried potatoes were found to increase with frying time and also followed a first order kinetic model. Temperature sensitivity of rate constants was adequately described by Arrhenius and z-value models. [source] Magnetic Resonance Temperature Mapping of Microwave-Fried Chicken FingersJOURNAL OF FOOD SCIENCE, Issue 5 2009Isil Barutcu ABSTRACT:, The main objective of this study was to compare the heating patterns of chicken fingers deep-fried conventionally and using a microwave. Two dimensional internal temperature maps of fried chicken fingers with rectangular geometry were measured post frying using magnetic resonance imaging (MRI). Frying was performed in a microwave oven at 365 W power level for 0.5 and 1.5 min after bringing the oil temperature to 180 ± 1 °C. Samples were also fried in a conventional fryer at 180 °C for 2 and 5 min for comparison. Variations in internal temperature distribution increased proportionally to frying time in both microwave and conventional frying. Internal thermal equilibrium is reached in all samples after 13 min of holding time. Internal structural changes, void formation, were also visualized in the images. Void formation did not significantly impact cooling rates. [source] Reduction of Acrylamide Formation in Potato Chips by Low-temperature Vacuum FryingJOURNAL OF FOOD SCIENCE, Issue 8 2004C. Granda ABSTRACT: Potatoes and other foods that have a high content of the amino acid asparagine and a high accumulation of reducing sugars are subject to the formation of acrylamide upon frying. The objectives of this research were (1) to analyze the level of acrylamide formed during deep-fat frying of potato chips and (2) to evaluate means of reducing acrylamide in potato chips by using different potato cultivars and vacuum frying. Several potato cultivars were used in this research, including Innovator (I), NDTX 4930,5W (N), ATX 854 04,8W (ATw), Atlantic (A), Shepody (S), ATX847806,2Ru (ATr), and White-Rose (W). An electric bench-top (atmospheric conditions)-type fryer was used to fry the potatoes. Three temperatures were used: 150 °C, 165 °C, and 180 °C. The vacuum frying experiments were performed at 118 °C, 125 °C, and 140 °C and a vacuum pressure of 10 Torr. The potatoes were sliced (1.5-mm thick) and fried for different lengths of times. For potatoes fried at 165 °C (for 4 min) at atmospheric conditions, the acrylamide contents were 5021 ± 55 ppb (W), 552 ± 25 ppb (I), 358 ± 50 ppb (N), 397 ± 25 ppb (ATw), 646 ± 55 ppb (A), 466 ± 15 ppb(S), and 537 ± 14 ppb (ATr). Vacuum frying reduced acrylamide formation by 94%. Results showed that both cultivar and modified frying systems can play an important role in reducing acrylamide formation in fried potatoes. As the frying temperature decreased from 180 °C to 165 °C, acrylamide content in potato chips reduced by 51% during traditional frying and by 63% as the temperature decreased from 140 °C to 125 °C in vacuum frying. Increased frying time increased acrylamide formation during traditional frying for all temperatures and frying methods analyzed. However, the effect on acrylamide concentration was greater for the traditional frying than the vacuum frying. Keywords: acrylamide, vacuum, frying, potato, temperature [source] Thermal Inactivation of Salmonella Senftenberg and Listeria innocua in Beef/Turkey Blended Patties Cooked via Fryer and/or Air Convection OvenJOURNAL OF FOOD SCIENCE, Issue 5 2002R.Y. Murphy ABSTRACT: Beef/turkey blended patties, containing 107 to 108 cfu/g of Salmonella Senftenberg or Listeria innocua, were battered and breaded. The effect of frying (177 °C) and air convection cooking (288 °C) on thermal inactivation of S. Senftenberg and L. innocua was evaluated. A model was obtained to correlate product internal temperature with frying and oven cooking time. Cooking method significantly affected thermal history and subsequently the thermal inactivation of S. Senftenberg and L. innocua. The effect of frying time interacted with oven cooking time. Increasing frying time reduced the oven cooking time. Mathematical models were developed to correlate the survival rate of S. Senftenberg or L. innocua with frying and oven cooking time. [source] MECHANICAL PROPERTIES OF A FRIED CRUST,JOURNAL OF TEXTURE STUDIES, Issue 1 2001ISABEL LIMA A restructured potato model system was fried in canola oil for 5, 10, or 15 min at 170, 180, or 190C and tested in a Dynamic Mechanical Analyzer. Selected mechanical properties were measured using puncture and three-point bending cells. Forces involved in puncture were a combination of tension, compression, and shear, while the three-point bend test studied the crust flexural properties. Crust deformability seemed to be governed by internal structural yielding. Maximum force at rupture increased significantly with both frying time and temperature. Failure criteria identified and standardized types of failure observed during bending tests. [source] Characterization of deep-fat frying in a wheat flour,water mixture model using a state diagramJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2007Pariya Thanatuksorn Abstract BACKGROUND: Crispness is an important characteristic to be controlled in deep-fat fried products. The physical state of food polymers influences the development of cellular structure and textural qualities of fried food. Glassy state is believed to play an important role in the mechanical properties of low-moisture food. Therefore, an understanding of the physicochemical phenomena in the development of fried food structure using a state diagram of the frying process is discussed. RESULTS: Wheat flour models containing 400 and 600 g kg,1 initial moisture content were fried in frying oil at 150 °C for 1,7 min. Thermal properties of wheat flour, structure alteration and textural properties of fried samples were evaluated. The porous structure continuously enlarged when the sample was in the rubbery state. As the frying time was prolonged, the state of the product became glassy due to a decrease in water content, resulting in the ceasing of porous enlargement. Conclusion: The results revealed that physicochemical changes during frying influence the alteration of microstructure and quality of fried food, and the state diagram could be applied to explain the formation of microstructure during the frying process and used as a decision-making tool to choose the proper conditions to provide desirable qualities in fried food. Copyright © 2007 Society of Chemical Industry [source] A chromametric method for the rapid assessment of deep frying oil qualityJOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2003Xin-Qing Xu Abstract A rapid chromametric method was developed for the assessment of deep frying oil quality based on the strong correlation between colour index and total polar compounds in deep frying oil. Colour indices of frying oil samples, measured by chromameter, decreased significantly during frying and were strongly correlated with frying time (r , 0.95, p < 0.001). Colour indices of a set of oil samples taken from 0 to 80 h of deep frying were also significantly correlated with total polar compounds of the same samples determined using the official method of the American Oil Chemists' Society (r = 0.96, p < 0.001). The equation for conversion of the colour index (x) to the content of total polar compounds (y) in an oil sample is y = 0.0174x2 , 2.9506x + 124.34. In addition, colour indices of 10 different types of frying oils were strongly correlated with the corresponding contents of total polar compounds in the oils with samples taken from 0 to 80 h of deep frying in duplicate (r = 0.95, p < 0.001, n = 220). The results of colour index analyses agreed well with the results of chemical and sensory analyses of the frying oils tested. This chromametric method is rapid, convenient and reliable. Copyright © 2003 Society of Chemical Industry [source] KINETICS OF ACRYLAMIDE FORMATION DURING TRADITIONAL AND VACUUM FRYING OF POTATO CHIPSJOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2005CLAUDIA GRANDA ABSTRACT Acrylamide is considered a carcinogen in animals and a possible carcinogen in humans. It has been found in starch-rich foods cooked at high temperatures. Vacuum frying (10 Torr) was investigated as a possible alternative to reduce acrylamide formation in potato chips. The cultivar Atlantic was used to determine the kinetics of acrylamide formation during traditional and vacuum frying at different temperatures. There was a 94% decrease in acrylamide content when potatoes were fried to the same final moisture content (1.5% ± 0.3% w.b.) under vacuum compared to those fried under atmospheric conditions. Acrylamide accumulation under vacuum frying was modeled using first-order kinetics (during traditional frying, the logistic kinetic model was used). The behavior of the kinetics of acrylamide content in potato chips fried under the two processes was different mainly because of the different temperatures used. During traditional frying, higher temperatures are used (150 to 180C) and acrylamide after some time is produced but starts degrading, producing a constant level of acrylamide content at longer times. During vacuum frying (10 Torr), acrylamide increased exponentially (but at lower levels) for all frying times. [source] Tastier and Healthier Alternatives to French FriesJOURNAL OF FOOD SCIENCE, Issue 4 2010Caius M. Rommens ABSTRACT:, The effect of both the origin and shape of potato cuts on fry quality was investigated in this study. Linear strips from the inner core of tubers were compared to those from outer tissues, both before and after processing, and strips from either specific tissues or whole peeled tubers were also evaluated against ring-shaped cuts. Both strips and rings had 0.7 cm sides and, in most cases, a volume of 4.9 cm3. They were analyzed for moisture content, antioxidants, asparagine, and reducing sugars. The material was then blanched, dipped in 0.5% disodium acid pyrophosphate and 0.3% glucose, dried at 77 °C, par-fried in soybean oil at 191 °C, and finish-fried at 168 °C. The fried product was analyzed for sensory characteristics and oil, salt, and acrylamide content. Our results showed that strips from the inner core absorbed 28% more oil and exhibited inferior sensory characteristics compared to strips from the outer parts. The extended drying and frying times needed to match the crispness and flavor of inner strips to those of regularly fried outer strips resulted in a further increased absorption of oil and, importantly, triggered a 163% increase in levels of the toxic Maillard reaction product acrylamide. Potato rings consisted of higher dry matter material, contained more antioxidants, and had a lower surface-to-volume ratio than the conventional linear strips. Upon processing, they also absorbed 22% less oil, contained 26% less salt, and displayed superior sensory properties. Thus, ring fries may represent an attractive alternative to French fries as processed staple food. [source] Structure Oil-Absorption Relationships During Deep-Fat FryingJOURNAL OF FOOD SCIENCE, Issue 9 2003P. B OUCHON ABSTRACT Analysis of the oil-absorption process in deep-fat fried potato cylinders (frying temperatures of 155°C, 170°C, and 185°C) allowed to distinguish 3 oil fractions: structural oil (absorbed during frying), penetrated surface oil (suctioned during cooling), and surface oil. Results showed that a small amount of oil penetrates during frying because most of the oil was picked up at the end of the process, suggesting that oil uptake and water removal are not synchronous phenomena. After cooling, oil was located either on the surface of the chip or suctioned into the porous crust microstructure, with an inverse relationship between them for increasing frying times. [source] | ||||||||||