Effect Of Frying Conditions Research Articles

Effect of Frying Conditions on Self-Heating Fried Spanish Mackerel Quality Attributes and Flavor Characteristics.

In this study, we investigated the effects of different frying conditions on the quality characteristics of fried Spanish mackerel (Scaberulous niphonius) to address the food quality degradation of self-heating fish products after frying, sterilization, and reheating. Furthermore, the effect of different moisture contents (65%, 60%, 55%, and 50%) of fried Spanish mackerel on texture, color, and microstructure after sterilization and self-heating were examined. The flavor fingerprints of different frying temperatures (140 °C, 160 °C, 180 °C, and 200 °C) coupled with the optimal moisture content were identified; furthermore, volatile organic compounds (VOCs) were studied using headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) with principal component analysis (PCA). The results indicated that the shear force value significantly increased, while the hardness and chewiness significantly decreased simultaneously with decreasing moisture content. Samples containing 65% moisture content showed the highest L*, a*, and W values, while their b* value was the lowest, and the most clearly visible fibrous veins with tiny cracks could be observed in them. Samples fried at 160 °C and 65% moisture content exhibited the richest VOCs, with a greasy or fried aroma. Based on the PCA, there were significant differences in the sample VOCs under different frying conditions. In summary, among all treatments, frying at 160 °C with 65% moisture content resulted in the highest food quality of fish filets. The results of this study could provide a theoretical basis for improving the food quality of self-heated fish products.

A study on monitoring of frying performance and oxidative stability of cottonseed and palm oil blends in comparison with original oils

ABSTRACTBlending polyunsaturated oils with highly saturated or monounsaturated oils has been studied extensively; however, in literature there is negligible information available on the blending of refined cottonseed oil with palm olein oil. Blending could enhance the stability and quality of cottonseed oil during the frying process. In the present study, the effects of frying conditions on physicochemical properties of the palm olein-cottonseed oil blends (1:0, 3:2, 1:1, 2:3, and 0:1, w/w) were determined and compared to the pure oils. The frying process of frozen French fries was performed in duplicate at 170 ± 5°C for 10 h without interruption. The oil degradations were characterized during deep-frying applications; peroxide, free fatty acid, and iodine value by standardized methods, fatty acid profile by using a gas chromatography-flame ionization detector, polar and polymeric compounds by using the high-performance size exclusion chromatography/evaporative light scattering detector technique. The present study clearly indicated that the oxidative and frying performances of pure palm olein oil and cottonseed oil significantly improved by blending application. Results clearly indicated that the frying performance of cottonseed oil significantly improved by the blending with palm olein oil. Except that free fatty acid content, all the physicochemical variables were significantly influenced by type of pure and blend oils. By increasing the proportion of palm olein oil in cottonseed oil, the levels of polyunsaturated fatty acids decreased, while saturated fatty acid content increased. The progression of oxidation was basically followed by detecting polar and polymeric compounds. The fastest increments for polar and polymeric compounds were found as 6.30% level in pure cottonseed oil and as 7.07% level in 40% cottonseed oil:60% palm olein oil blend. The least increments were detected as 5.40% level in 40% cottonseed oil:60% palm olein oil blend and 2.27% level in 50% cottonseed oil:50% palm olein oil blend. These levels were considerably below the acceptable levels recommended by the official codex. Therefore, the present study suggested that blending of cottonseed oil with palm olein oil provided the oil blends (50% cottonseed oil:50% palm olein oil and 40% cottonseed oil:60% palm olein oil, w/w) with more desirable properties for human nutrition.

Effect of frying conditions on fatty acid profile and total polar materials via viscosity

This work investigates how the temperature dependence of soybean oil viscosity varies with frying conditions and chemical composition, to develop a model that predicts oil degradation directly from process parameters. The temperature dependence of frying oil viscosity is described using Lioumbas et al. (2012) non-linear model, which is confirmed with satisfactory accuracy (r2>0.9998). Two models, predicting viscosity separately from frying conditions and chemical composition, are established, both with an overall accuracy of greater than 95.0%. Using the viscosity parameter as a medium, multiple quasi-linear regression analysis was applied to derive an expression that predicts fatty acid composition and total polar materials from the average oil temperature and the frying time (r2=0.930). This final expression quantifies the relationship between the frying conditions and the chemical composition of the oil, which is convenient for on-site quality control.

Effects of frying conditions on the formation of heterocyclic amines and trans fatty acids in grass carp (Ctenopharyngodon idellus)

The effects of frying temperature and the number of frying cycles on the formation of heterocyclic amines (HAs) and trans fatty acids (TFAs) in grass carp were investigated. 9t-18:1 FAs was detected in all samples. The TFA contents of samples fried at 150–210°C were not significantly different (P>0.05). The content and number of different types of HAs increased with increasing frying temperature. 9H-pyrido[3,4-b]indole (Norharman), 1-methyl-9H-pyrido [3,4-b]indole (Harman), and 2-amino-3,7,8-trimethylimdazo[4,5-f]quinoxaline (7,8-diMeIQx) were detected in most of the tested samples. The differences in the surface colour (ΔE) increased with frying temperature, and ΔE of samples fried at 170°C was significantly higher than that of 150°C (P<0.05). The analysis of different cycle times revealed that the TFA levels increased with an increase in the usage period of the frying fat, and 9t,12t-18:2 FAs was detected after the 40th frying cycle. As the number of frying cycles increased, the number of different types of HAs increased, seven types of HAs were detected after the 25th frying cycle.

Effect of frying conditions on the physico-chemical properties of rice bran oil and its blended oil.

The changes occurring in rice bran oil and its blend with sunflower oil during repeated frying cycles of dried and moist potato chips were monitored. The parameters assessed were: Colour, Refractive Index, SpecificGravity, Oryzanol Value, Free fatty acid, Iodine Value, Peroxide value, anisidine value, Saponification Value, trans fats and fatty acid composition. No significant changes (p≤0.05) were observed in the refractive index and specific gravity of rice bran oil, sunflower oil and their model blend. The colour of blended oil was lesser than RBO and the intensity of color increased after each frying cycle during the deep fat frying of moistened and dried potato chips. The oryzanol content and iodine value decreased with the frying cycles. The decrease in oryzanol value during the frying operation was more prominent in rice bran oil as compared to the blended oils. The increase in p-anisidine value was more in rice bran oil as compared to blended oil. No significant changes (P<0.05) in the myristic, palmitic and stearic acid composition was observed during the repeated deep fat frying cycles in both the rice bran oil and blended oils samples. The amount of unsaturated fatty acid decreased gradually during repeated deep fat frying cycles in both the oils. The trans fat increased with repeated deep fat frying cycles in both the rice bran and blended oils, when used to fry moistened and dried potato chips. Both the oil samples showed greater formation of trans fatty acids when the moistened potato chips were used during frying.

Jilebi 3: Effect of frying conditions on physical characteristics.

The process of jilebi making includes the frying of specially shaped batter strands to obtain a crisp texture followed by absorption of sugar syrup. The effects of frying temperature (150-180°C) and time (15-300s) on the physical characteristics have been investigated; these are moisture and fat contents, density, colour, textural attributes and microstructure. Among the textural parameters obtained by shearing the jilebi strands, shear failure force and the number of minor fractures increase markedly with an increase in time of frying. The brightness of the sample is lower when fried at higher temperatures like 180°C compared to that of 150°C; the hue or dominant wavelength of batter prior to frying is 578.0nm, and after frying, it is between 564.8 and 591.3nm indicating an overall shift towards yellow colouration during frying. The density of the jilebi strands decreases along with moisture content, while fat content increases gradually with an increase in frying time. The microstructure and image analysis of the fried products indicate the creation of porous structure consisting of several pores that are separated by thin cell walls of thickness between 10 and 15μm. The eccentricity of pores/vacuoles in jilebi is between 0 and 0.92 indicating a close resemblance to elliptical shapes. The samples fried at 160°C for 180-240s have been judged as the best sample both as fried and fried-sugar syrup soaked products.

The effect of frying conditions on moisture loss and oil uptake in yam slices (Dioscorea alata)

The effect of frying conditions on immersion on moisture loss and oil content were studied at different times in two yam varieties: Diamante 22 and Pico Botella. The experimental data adjusted itself to the first order exponential model for humidity transfer (r &gt; 0.9) for both cultivars. The humidity diffusion coefficient for the two varieties of yam fried at 140°, 160° and 180°C for 1 to 9 minutes were 8.11±0.76, 8.2±0.81, and 8.62 ±0.71*10-9 m2/s for the Diamante 22 variety, respectively, and 8.32±0.82, 8.38±0.78, 8.54±0.84*10-9 m2/s for the Pico de Botella variety. Activation energy was 24.43 kJ/mol for the Diamante 22 variety and 21.27 kJ/mol for the Pico de Botella variety. The results showed that there was higher oil absorption after 180 s and at 140°C while taking into account 0.377 kg water / kg solid moisture loss for Diamond 22 and 0.410 kg water / kg solid Pico de Botella at 180°C for 540 s.

Measurement of evaporated acrylamide during frying of potatoes: Effect of frying conditions and surface area-to-volume ratio

The amount of acrylamide lost through water vaporization during frying of potatoes was quantified in this study. Water vapor was condensed by a cold trap, and then analyzed for acrylamide content. Acrylamide content of potato samples was also determined. In order to assess the thermal effect on acrylamide formation, surface and internal temperatures of potato samples were measured during frying. Effect of frying oil temperature (150 °C, 170 °C, and 180 °C), time (1, 3, and 5 min) and surface area-to-volume ratio (strips, cubes, and discs) on both acrylamide level of potato samples and the evaporated acrylamide was investigated. The percentage ratio of the amount of acrylamide lost by evaporation ranged between 0.7 and 1.8 during frying of potato at temperatures ranging between 150 °C and 180 °C. Based on these results it is concluded that although a fraction of the acrylamide formed during frying is removed with vaporizing water, it appears to be insignificant. The results, on the other hand, indicated that air exposure to acrylamide could be a concern from the viewpoint of risk assessment for a group of people working on frying operations.

Effects of frying conditions and yeast fermentation on the acrylamide content in you-tiao, a traditional Chinese, fried, twisted dough-roll

Abstract The effects of frying temperature, frying time, and dough pH on the formation of acrylamide in the processing of you-tiao, a traditional Chinese, fried, twisted dough-roll, were analyzed using response surface methodology. The results obtained showed that the frying time and temperature as well as dough pH had a notable impact on the formation of acrylamide in the products. It was demonstrated that lowering the frying temperature to 175 °C, prolonging the frying time to 86 s, and adjusting the dough pH to 6.0 with citric acid reduced the acrylamide content by 71% in the finished products. An examination of the influence of yeast fermentation on the free asparagine and reducing sugars revealed that the addition of 0.8% yeast fermented for one hour could reduce the amount of acrylamide formed in the fried, twisted dough-roll by 66.7%.

Effect of frying conditions on moisture, fat, and density of papad

The moisture transfer mechanism by diffusion and uptake of frying oil was studied during deep fat frying of papads with an initial moisture content (IMC) 24.8% dry basis (db). The experimental data were found to fit well to a first order exponential model for moisture transfer (with a regression coefficient 0.99). The apparent moisture diffusivity of papad in the frying time range of 0–20 s at temperatures of 165, 175, 180 and 185 ± 1 °C were 2.83, 3.65, 3.87 and 5.03 × 10 −9 m 2 s −1, from which the activation energy (45 kJ mol −1) was calculated by using Arrhenius type equation. The optimum experimental frying parameters for maximum diametrical expansion (46.4%) were noted to be: oil temperature 185 ± 1 °C, moisture 1.2%db, oil absorption (47.3%db), density 377 kg m −3 for frying time of 20 s.

DEEP FAT FRYING OF POTATO STRIPS—QUALITY ISSUES

Moisture loss and oil adsorption kinetics, structural properties (apparent density, true density, specific volume and internal porosity), color changes and viscoelastic behavior (compression tests, crispness) were investigated during deep fat frying of french fries. The effect of frying conditions (oil temperature, sample thickness and oil type), drying pretreatment and osmotic dehydration pretreatment on the above properties was also examined. The results showed that oil temperature and thickness of potato strips have a significant effect on oil uptake, moisture loss and color parameters of french fries, while the use of hydrogenated oil in the frying medium does not affect these properties. The porosity of french fries increases with oil temperature increases and sample thickness and it is higher for products fried with hydrogenated oil. Maximum stress and maximum strain increase during frying, while crispness of potato strips is higher for hydrogenated oil, and lower for refined oil. Air drying and osmotic pretreatment increase porosity of fried potatoes but decrease their oil and moisture content. A negative effect on color development with drying time was also observed. Pre-fry drying as well as osmotic pre-treatment increases the maximum stress and maximum strain of french fries during frying. Air drying pre-treatment increases the crispness of potato strips while osmotic pre-treatment does not affect it, with the exception of sugar solutions.

Colour changes during deep fat frying

The effect of frying conditions on the colour changes during deep fat frying of french fries has been investigated. The Hunter colour scale parameters redness, yellowness and lightness were used to estimate colour changes during frying as a function of the main process variables (oil temperature, oil type and sample thickness). A first-order kinetic equation was used for each one of the three colour parameters, in which the rate constant is a function of the main process variables. The results showed that oil temperature and thickness of potato strips have a significant effect on the colour parameters, which are not affected by the use of hydrogenated oil in the frying medium.

Effect of frying conditions on shrinkage and porosity of fried potatoes

Apparent density, true density, specific volume and internal porosity were investigated during deep fat frying of french fries. The effect of frying conditions (oil temperature, sample thickness and oil type) on the above properties was examined. A simple mathematical model was used to correlate the above properties with oil and moisture content. Five parameters with physical meaning were incorporated into the model: the enclosed water density ρ w, the enclosed oil density ρ L, the dry solids density ρ s, the dry solids bulk density ρ bo and the volume shrinkage coefficient β ′. Moisture and oil content during deep fat frying and consequently all the examined properties are affected by frying conditions. The results showed that the porosity of french fries increases with oil temperature increases and sample thickness and it is higher for products fried with hydrogenated oil.