Frying Time Research Articles

The effect of pan frying on thermooxidative stability of refined rapeseed oil and professional blend.

The pan fryings of frozen pre-fried French fries in refined rapeseed oil (RO) and professional blend (PB) were of 8h duration. Initially, while fresh, and after every 1h of frying, the oils were analyzed for acid and anisidine values, colour, refractive index, fatty acid composition (by GC), polar fraction content and composition (by high pressure size exclusionchromatography). Additionally the fat content and fatty acid composition of French fries were determined. Hydrolytic and oxidative changes in the frying media varied with oil composition and increased with frying time. The pace of oxidation in RO was three times higher than in PB. The loss of polyunsaturated fatty acids (sum of C18:2 and C18:3) after 8h of frying was 7% in PB and 20% in RO. The polar fraction content was two times lower in PB, but did not exceed 25% in either of the frying media. The predominant fraction in RO was oxidized triacylglycerols, while in PB - diacylglycerols. During frying the proportions of triacylglycerol polymers and dimers increased in both oils, reaching 32% in RO and 23% in PB.

Effect of Frying Parameters on Mechanical Properties and Microstructure of Potato Disks

AbstractThe effect of frying temperature and time on surface pore characteristics, oil content, moisture loss and mechanical properties of potato disks is investigated. Scanning electron microscopy is used to study the surface pore characteristics and rheological behavior is investigated using a dynamic mechanical analyzer. Both frying temperature and frying time had a significant impact on the pore area, creep behavior, moisture loss and fat uptake of potato disks. The changes in pore area and creep compliance were dynamic and, in turn, affected the oil uptake and moisture loss rates. Average open pore area and percent open pore area increased to 1.15 μm2 and 14.04%, respectively, during the middle frying stages. Higher frying temperature resulted in faster structural degradation, moisture loss and oil uptake during initial frying stages. Higher frying times tended to increase the percentage open pore area.Practical ApplicationsThe article investigates structural and mechanical changes in potato disks during frying. These are crucial to understand the transport mechanisms during frying, and to study the role played by the product microstructure on both oil uptake and texture development. The creep compliance function reported in this article is useful for predicting the texture of potatoes via mathematical models describing the frying.

Physicochemical and organoleptic characteristics of deep-fat fried and microwaved potato chips

This study was carried out to examine the effects of deep-fat frying and microwaving on various physicochemical parameters and sensory characteristics of potato chips. The moisture content of deep-fat fried potato chips was found to decrease faster than that of microwaved chips during the cooking process. The fat content of the deep-fat fried potato chips increased with increasing frying time, while that of microwaved chips changed little. Microwaving was found to increase the hardness and lower the acrylamide content of the chips. Microwaving also resulted in chips with a lower browning index and a lighter color than deep-fat fried chips. Although deep-fat fried chips were found to be superior in terms of appearance, color, and overall acceptability, no significant differences were determined in the taste and crispiness between deep-fat fried and microwaved potato chips. Our findings indicate that microwaving as a cooking method has the potential to yield potato chips with low acrylamide levels, low fat content, and a desirable texture. Microwaving can therefore be considered a suitable method of preparing potato chips for modern people who consume excessive fats and oils and are interested in healthier and high-quality products.

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.

Esters of 3-monochloropropane-1,2-diol and glycidol: no formation by deep frying during large-scale production of potato crisps

Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPDE) as well as 2,3-epoxy-1-propanol (glycidol, GE) can occur as undesirable foodborne toxicants in fats/oils and related products. Because of their significant toxicity, it is a worldwide aim to minimize levels of 3-MCPDE and GE, and several research programmes are currently trying to gain further understanding of their formation. Here we report on the non-formation of 3-MCPDE and GE during the deep frying of potato crisps in large-scale industrial production using high-oleic sunflower oils (HOSO). Samples of potato crisps and corresponding frying oils were taken in nine series at several frying time points and subsequently analysed by GC–MS. The analysed samples (crisps and frying oils) showed very low levels of both contaminants varying between 0.10 and 0.85 mg/kg fat for 3-MCPDE and between 0.09 (LOQ) and 0.91 mg/kg fat for GE. The results indicate no significant change of either 3-MCPDE or GE levels during frying. Thus, the endogenous formation of 3-MCPDE and GE during frying of potato crisps using HOSO and typical large-scale conditions can be excluded.

Effect of low temperature on the microwave-assisted vacuum frying of potato chips

ABSTRACTThe objective of this study was to investigate the effect of low temperature on the microwave-assisted vacuum frying of potato chips. A newly built, in-house, microwave-assisted frying machine was developed and used in this study. The effect of low temperature on the microwave-assisted vacuum frying of potato chips was investigated via comparing sample properties prepared with frying temperatures of 90°C, 95°C, and 100°C. The experience was taken at the same vacuum degree in every frying process. Parameters of included moisture content, oil content, color parameters (lightness, redness, and yellowness), and textures (hardness, crispness) were used to evaluate the effect of different frying temperatures on the microwave-assisted vacuum frying of potato chips. Results showed that with lower temperature in microwave-assisted frying, the rate of moisture evaporation of potato chips was slowed down and the time of the ending of frying was prolonged from 10 min with a frying temperature of 100°C to 14 min with 90°C and 12 min with 95°C. Meanwhile, the oil content in fried potato chips was increased with lower temperature in microwave-assisted vacuum frying. The breaking force of final products are not significantly (p > 0.05) affected in different frying temperatures of microwave-assisted vacuum frying. Also, the frying temperature of 100°C in microwave-assisted vacuum frying had better preservation of natural color than the lower frying temperature with prolonged frying time. Results showed that the temperature is one of the main factors that affect the quality of microwave-assisted vacuum frying of potato chips and the producer could find suitable temperature conditions according to experience.

Screening of Significant Variables for Sliced Frying Fish Ball using Plackett–Burman Design

Screening of significant variables of Sliced Frying Fish Ball (Basreng) has been conducted using Plackett-Burman Design, a statistical method commonly used to reveal the significance of variables in the product development. Four variables were selected namely tapioca flour, potato flour, fish, and frying time. Twelve formulations were peformed and the final products were analyzed for their sensory and texture parameters. Six responses were chosen (appearance, color, odor, taste, texture, overall acceptance and hardness) and then evaluated based on their significance, coefficient value and ranking test through appropriate statistical analysis. The result showed that four variables gave positive and negative effects to the products. Based on overall ranking test, tapioca flour was placed at the first place meaning that it had highest desirable properties followed by frying time, potato flour, and fish flesh. The overall rank test for each ingredient and the attributes provided a reliable data/information to select the most compatible ingredients for further optimization experiment.

Effect of Pretreatments and Air‐Frying, a Novel Technology, on Acrylamide Generation in Fried Potatoes

This paper investigated the effect of air-frying technology, in combination with a pretreatment based of soaking the samples in different chemical agent solutions (citric acid, glycine, calcium lactate, sodium chloride, or nicotinic acid [vitamin B3]), on the generation of acrylamide in fried potatoes. The influence of reducing sugars on the development of surface's color was also analyzed. The experiments were conducted at 180 °C by means of air-frying and deep-oil-frying, as a reference technology. Based on the evolution of color crust with frying time, it could be concluded that the rate of Maillard reaction decreased as the initial reducing sugars content increased in the raw material, and was also lower for deep-oil-frying than for air-frying regardless of pretreatments applied. Air-frying reduced acrylamide content by about 90% compared with conventional deep-oil-frying without being necessary the application of a pretreatment. However, deep-oil fried potatoes pretreated with solutions of nicotinic acid, citric acid, glycine at 1%, and NaCl at 2% presented much lower acrylamide levels (up to 80% to 90% reduction) than nonpretreated samples.

Process optimization by response surface methodology and quality attributes of vacuum fried yellow fleshed sweetpotato (Ipomoea batatas L.) chips

A three-level Box–Behnken design was employed to study the effects and optimize the process parameters for vacuum frying of yellow fleshed sweetpotato (YFSP) slices for the production of healthy and nutritious fried snacks. The critical factors selected for the investigation were frying temperature (108–136°C), vacuum pressure (4.91–19.91cmHg) and frying time (3–9min). The experimental results were fitted with a second-order polynomial equation by a multiple regression analysis and more than 80% of the variation could be predicted by the models. The optimal conditions for vacuum frying of YFSP slices determined using the numerical analysis were vacuum pressure of 10.12cmHg at 108°C for 9min with desirability concept of 0.609. When optimized, vacuum fried samples were compared with atmospheric fried samples; the former absorbed about 60.42% less oil, and retained higher carotenoid (6.01mg/g), with lower breaking force (15.9N). Panellists preferred and accepted the optimized vacuum fried samples in all the sensory attributes investigated. The results suggested that vacuum frying of yellow fleshed sweetpotato chips is a better alternative to produce fried chips of acceptable and nutritional qualities.

Study of oil uptake during deep-fat frying of Taro (Colocasia esculenta) chips

The effects of a water blanching pretreatment (BP, 85°C for 3 min), sample thickness (1 and 2 mm), oil temperature (180 and 200°C), and frying time (1 and 3 min) on the oil uptake (OU) behavior during the deep-fat frying of pre-dried (oven dried at 70°C for 20 min) taro (Colocasia esculenta) chips were investigated. Results demonstrated that using short frying times and high oil temperatures causes OU to decrease in both blanched and non-blanched samples (p < 0.01). In addition, higher product thicknesses were found to increase OU in non-blanched taro chips, while the opposite trend was found for the blanched slices (p < 0.01). BP also affected the OU, yielding lower fat contents (up to 80% of OU reduction) (p < 0.05), thus allowing the development of a fried taro product with reduced fat content (less than 30% fat content in dry basis).

Vacuum frying of breaded shrimps

Vacuum frying (VF) was tested as an alternative technique to produce high-quality fried food. This study investigated the effects of oil temperature on the moisture loss, oil uptake, texture, color, and acrylamide content of vacuum-fried versus atmospheric-fried breaded shrimps. The moisture loss and oil absorption of breaded shrimps during VF were significantly affected (p < 0.05) by oil temperature. Oil absorption was directly proportional to moisture loss during VF. The oil absorption of breaded shrimps during VF increased with increasing temperature for the same frying time. After 10 min of frying, the oil contents of breaded shrimps fried at 80 °C, 100 °C, and 120 °C under vacuum conditions were 0.20 ± 0.013, 0.23 ± 0.012, and 0.25 ± 0.019 goil/gdry solid, respectively. These values were significantly lower than those (0.32 ± 0.019 goil/gdry solid) obtained under atmospheric conditions (170 °C). VF effectively decreased the acrylamide content of breaded shrimps. Furthermore, breaded shrimps with desirable color and low hardness can be produced using VF. These results indicate that VF is a feasible alternative technique to produce high-quality breaded shrimps.

Study on the correlation of acid value and total polar compounds in frying oil

Take sea seed oil, olive oil and palm oil as the main material, the changes of acid value and total polar compounds after frying and essential fatty acids at 180℃ was studied. It was found that acid value significantly increased in three oils with the frying time ( p < 0.05) increase. After frying 20 times, the total polar compounds in three oils ( TPC) increased significantly, the total polar compounds of camellia oil, olive oil and palm oil were16.01%, 20.91% and 17.66% respectively.The final acid value of camellia seed oil, olive oil and palm oil were 0.32, 0.66 and 0.58 mg / g. With increasing number of frying, the frying of three oils saturated fatty acid significantly increased.Unsaturated fatty acids varied widely, C18 ∶ 2, and C18 ∶ 3 was significantly decreased, while C18 ∶ 1decreased gradually.

Feasibility of Continuous Frying System to Improve the Quality Indices of Palm Olein for the Production of Extruded Product.

Comparative frying studies on the processing of extruded product were conducted under intermittent and continuous frying conditions using two separate frying systems, i.e batch and pilot scale continuous fryers, respectively. Thermal resistance of palm olein were assessed for a total of 5 days of frying operation at 155°C - the unconventional frying temperature gave the product moisture content of 3% after intermittent and continuous frying for 2.5 min and 2 min, respectively. The formation of free fatty acid in palm olein in the case of intermittent frying was more than 2-fold higher compared to its counterpart (0.66%). Smoke point inversely evolved with oil acidity: the value dropped progressively from 215 to 177°C and from 219 to 188°C when extruded product was intermittently and continuously fried, respectively. In the light of induction period, repeated frying exhibited a gradual decrease in the value after 5 days of frying (12.2 h). Interestingly, continuous frying gave somewhat similar induction period, as demonstrated by fresh palm olein, across frying time. Frying at lower temperature, to some extent, provides opportunity for palm olein to retain 74% of its initial vitamin E during continuous frying. This benefit, however, is somehow denied when extruded product was processed under intermittent frying conditions--only 27% of vitamin E was remained at the end of frying session. Regardless of frying protocols, transient in polar compounds was minimal and hence comparable. The colour in the case of continuous frying appeared to be darker due to higher degree of oil utilisation for frying. The data obtained will provide useful information for food processors on how palm olein behaves when frying is undertaken under different frying protocols.

Obtención de parámetros tecnológicos para la elaboración de productos nixtamalizados, tipo snacks fritos, a partir de cereales alto andinos

Objetivo: Elaborar Productos Nixtamalizados a partir de Cereales Alto Andinos (Maíz, Quinua y Kiwicha).&#x0D; Método: Es una investigación científica tecnológica de diseño experimental, aplicada para determinar el proceso de nixtamalización con cereales alto andinos. El Método propuesto es el proceso de nixtamalización el cual consiste en el cocimiento del Cereales Alto Andinos (Quinua, Kiwicha y Maíz) en una solución alcalina elaborada con cal. Para lograr la remoción del pericarpio, suavizar la textura del grano e impartir el sabor característico a los productos nixtamalizados. Una vez cocidos los granos se molturan en húmedo para obtener una masa, la cual es laminada, cortada, horneada y frita. Para luego ser envasada en condiciones óptimas. Resultado: Se encontró los porcentajes adecuados de cal para la nixtamalización de la Quinua y la Kiwicha, los cuales fueron 1.5% y 1% respectivamente. El tiempo y temperatura adecuada para la cocción de la Quinua y la Kiwicha fue de 15min. Y 90°C para ambos cereales. El tiempo y la temperatura de horneado para la masa de cereales nixtamalizados fue de 7 min. Y 180°C. El tiempo y temperatura de fritura del producto fue de 1.5 min a 200°C. Conclusiones: Con los experimentos realizados se logró establecer un método adecuado para la elaboración de un nuevo producto nixtamalizado, demostrándose que es un producto rentable económicamente y de aceptación en la población consumidora de snacks fritos.

Modelling the kinetics of water loss during deep-fat frying of potato particulates

We developed an empirical model to describe the water loss during deep-fat frying. Raw potato particulates were sliced to form cylinders and subjected to the deep-fat frying at isothermal temperatures of 160, 190, and 220&amp;deg;C. The microstructure properties were assessed by Field Emission Scanning Electron Microscope (FESEM). The plot of the water content versus the frying time showed two distinct regions. A first-order kinetic model correlated with the two irreversible serial rate processes, rapid process and slow process, was hypothesised to describe the water loss during frying. The results showed the simultaneous two first-order kinetic models adequately predicted the water loss of potato particulates during isothermal frying. The effect of temperature on the rate constants, k&lt;sub&gt;1&lt;/sub&gt; and k&lt;sub&gt;2&lt;/sub&gt;, for the two processes was adequately modelled by the Arrhenius relationship. The observations of structural changes on the surface and in the inner section of potato particulates are critical. These physical pieces of evidence support our assumption that the mechanisms of the water loss (two-stage rate processes) before and after the transition time are different. &amp;nbsp;

Impact of Canolol‐Enriched Extract from Heat‐Treated Canola Meal to Enhance Oil Quality Parameters in Deep‐Frying: a Comparison with Rosemary Extract and TBHQ‐Fortified Oil Systems

AbstractCanolol‐enriched extracts obtained from the extraction of fluidized bed treated canola meal with supercritical carbon dioxide were added to high‐oleic canola oil in different concentrations (200, 500 and 750 mg/kg). After 30 h of deep‐fat frying, oils fortified with canolol‐enriched extracts showed a two to three times better frying performance in comparison to the commonly used antioxidants (TBHQ, 200 mg/kg; rosemary extract, 40 and 200 mg/kg) and a control without antioxidants with regards to the formation of di‐ and polymer triacylglycerols, total polar compounds, secondary degradation products (anisidine value) and the iodine value. The canolol‐enriched extracts were also able to slow down the degradation of α‐ and γ‐tocopherol during frying resulting in significant amounts of tocopherols after 30 h of frying in comparison to the other oils. The influence of the canolol‐enriched extracts indicated strongly concentration‐dependent performance. With increasing concentration of the extract, the thermal stability of the fortified oil was improved. The only disadvantage of the addition of the extracts was an increase in the initial acid value, but within the frying time, only oil fortified with 750 mg canolol‐enriched extract/kg reached the limit given in different countries.

Effect of Microwave-Assisted Vacuum Frying on the Quality of Potato Chips

We investigated the applicability of microwave-assisted vacuum frying in producing potato chips. Three microwave power levels (600, 800, 1000 W) were used for frying times of up to 360 s. The moisture loss and oil uptake histories were measured as a function of the microwave power levels. The textural crispness (breaking force) and color parameters (lightness, redness, and yellowness) were also measured as a function of microwave power levels and frying time. The application of microwave-assisted vacuum frying significantly increased the moisture evaporation and oil uptake rates in potato chips. At the same time, the amount of oil uptake was similar to that in vacuum-fried chips not assisted by microwave. The chips produced using microwave-assisted vacuum frying were crispier (lower breaking force), visually appealing, and could be produced in a shorter time.

Based on the Protection of Water Pack Polysaccharide Processing Technology and its Optimization

Purpose: For health water pack polysaccharide easy loss occurred during processing, establish a high retention rate of the processing method. Method: Chooseing slice thickness, heating time and temperature as the parameter, the water pack for steaming, boiled, Fried, baked oil heating treatment, determination of the water pack polysaccharide content, it is concluded that optimal process parameters, the retention rate of statistics. Results: The best conditions for water pack all kinds of processing method is: (1) steamed products: slice thickness of 1.6 cm, 106 °C steamed 10 mins; (2) boiled products: slice thickness of 1.2 cm, 90 °C cooked for 10 mins; (3) baked products: the slice thickness of 0.2 cm, 160 °C baking 14 mins; (4) Fried products: the slice thickness of 0.2 cm, and 150 °C the frying time of 5.5 mins. Processing products in water pack polysaccharide retention rate is as follows: Steaming &gt; Boiled &gt; Fried &gt; Baking. Conclusion: steamed processing for water pack polysaccharide retention rate is high, is the water pack of preferred processing method; Boiled, grilled, Fried method should choose low heating temperature.

Optimization of pneumatic sheet extrusion of whole wheat flour poory dough using response surface methodology.

Pneumatic extrusion of whole wheat flour dough is a challenge in the preparation of Poory. In the present study, the pneumatic extrusion process variables (pneumatic pressure, rate of extrusion) and quality of deep fried product (oil uptake, frying time, puffed height) was evaluated to get Poory of maximum overall sensory quality, minimum shear and minimum oil uptake. These parameters depend on the moisture content of wheat dough. Response surface methodology was demonstrated to be an efficient tool for the optimization of process parameters of pneumatic extrusion. The results indicated that extrusion pressure ranging from 3 ~ 6 × 10(5) Pa for the whole wheat flour dough with added moisture of 56 ~ 60% was found to give a uniform rate of extruded sheet. It was observed that submerged frying time for the extruded dough sheet was in the range of 35 ~ 40s, with the temperature of the vegetable oil to be in the range of 180 ~ 185°C. Oil uptake during frying was about 12 ± 1% and the textural shear force was found to be 9.9N with an overall sensory score of 7.2 ± 0.5 on nine point scale. The experimental errors for all attributes were non-significant (p > 0.05) and thus optimum variables predicted by the model are found suitable.

Effect of Chinese traditional cooking on eight pesticides residue during cowpea processing

Thermal processing can concentrate residues or convert residues to more toxic metabolites in food. Chinese traditional cooking pays more attention to thermal processing and more vegetables were eaten after thermal processing. In this study, the effect of Chinese traditional cooking (washing, blanching, stir-frying, frying and combined operations) on eight pesticides residues (pyridaben, procymidone, chlorothalonil, difenoconazole, α-cypermethrin, bifenthrin, S-fenvalerate and λ-cyhalothrin) in cowpea which was one of the most important legume crops in China was examined. Result showed washing and blanching could reduce residues with low Kow while stir-frying and frying were more effective to residues with high Kow; stir-frying and frying could concentrate residues with low Kow; the residue levels in oil increased following increasing frying time and frequency especially the residues with high Kow; one metabolite studied in this paper was not detected. Blanching (5min) followed by stir-frying (3min) was the most effective combined operation.