Frying Of Foods Research Articles

Optimization of culture conditions and bench-scale production of anticancer enzyme L-asparaginase by submerged fermentation from Aspergillus terreus CCT 7693

L-Asparaginase amidohydrolase (EC 3.5.1.1) has received significant attention owing to its clinical use in acute lymphoblastic leukemia treatment and non-clinical applications in the food industry to reduce acrylamide (toxic compound) formation during the frying of starchy foods. In this study, a sequential optimization strategy was used to determine the best culture conditions for L-asparaginase production from filamentous fungus Aspergillus terreus CCT 7693 by submerged fermentation. The cultural conditions were studied using a 3-level, central composite design of response surface methodology, and biomass and enzyme production were optimized separately. The highest amount of biomass (22.0 g·L−1) was obtained with modified Czapek–Dox medium containing glucose (14 g·L−1), L-proline (10 g·L−1), and ammonium nitrate (2 g·L−1) fermented at 37.2 °C and pH 8.56; for maximum enzyme production (13.50 U·g−1), the best condition was modified Czapek–Dox medium containing glucose (2 g·L−1), L-proline (10 g·L−1), and inoculum concentration of 4.8 × 108 espore·mL−1 adjusted to pH 9.49 at 34.6 °C. The L-asparaginase production profile was studied in a 7 L bench-scale bioreactor and a final specific activity of 13.81 U·g−1 was achieved, which represents an increase of 200% in relation to the initial non-optimized conditions.

Waste Cooking Oils as Feedstock for Lipase and Lipid‐Rich Biomass Production

Approximately 1 million tons of waste cooking oils (WCO) are generated in European Union per year. Oftentimes, these oily wastes are discharged through public sewerage systems, increasing the water treatment costs in wastewater treatment plants. The oleaginous yeast Yarrowia lipolytica W29 is used to simultaneously degrade WCO and to produce lipase (market demand is increasing due to its application in the field of bioenergy). A statistical experimental design based on Taguchi method is employed to assess the effect of initial medium pH, WCO, and arabic gum concentration on lipase production. Initial medium pH is found to be the most significant parameter and the interaction between WCO and arabic gum concentration had the highest influence for lipase production. Additionally, the effect of oxygen mass transfer is studied in batch cultures in a stirred tank bioreactor and the maximum lipase activity (12 000 U · L−1) is obtained at kLa of 16 h−1. Simultaneously with lipase production, also lipid‐rich biomass (48% of lipids mass per dry cellular mass), enriched in unsaturated fatty acids (oleic and linoleic acids) is obtained.Practical Applications: In this work it was demonstrated the possibility of replacing an expensive edible oil (olive oil) by a non‐edible oil waste (WCO) for lipase production. Moreover, no more wastes are produced, since whole cells of Yarrowia lipolytica W29 (lipid‐rich biomass), are a potential source for food supplements. Thus, the bioprocess described fulfill the requisites of circular economy: a low cost substrate is used as raw material, added‐value products (lipase and lipid‐rich biomass) are obtained and no further wastes are generated (take‐make‐dispose concept).Waste cooking oils (WCO) are generated from vegetable oils used at high temperatures in food frying. The biological degradation of WCO by the oleaginous yeast Yarrowia lipolytica W29, with concomitant production of added‐value compounds (lipase and lipid‐rich biomass), allows the reduction of pollutant burden of these oily wastes.

Effect of water content of high-amylose corn starch and glutinous rice starch combined with lipids on formation of starch-lipid complexes during deep-fat frying.

Moisture affects the combination of starch granules and fatty acids in deep-fat frying. In this study, high-amylose corn starch (HACS) and glutinous rice starch (GRS) with various water contents were fried in rapeseed oil at 170 °C for 7 min. The complex index (CI) of the GRS-lipid and HACS-lipid complexes improved as the moisture content increased from 6% to 40%; however, further increasing the water content from 40% to 60% led to a decrease in the CI. At a moisture content of 40%, the CI of the HACS-lipid complexes was higher than that of the GRS-lipid complexes. Fatty acid content analysis revealed that the total fatty acid content at different moisture contents in the HACS-lipid complexes was higher than that in the GRS-lipid complexes both before gelatinization and after enzyme hydrolysis. In addition, the total fatty acid content in the HACS-lipid complexes and GRS-lipid complexes at 40% moisture content was the highest among all the measured moisture contents. Scanning electron microscopy revealed that both the HACS and GRS granules lost their integrity after deep-fat frying, and no free lipid droplets were noted among the starch granules after defatting. Both Fourier-transform infrared spectroscopy and fluorescence microscopy verified that HACS combined with lipids yielded a stronger lipid-binding capacity than that of GRS at a moisture content of 40%. The study results may be potentially useful in the deep-fat frying of starchy food to produce foods with lower fatty acid content.

Modelling and Simulation of a Moving Boundary Problem Arising During Immersion Frying of Foods

A single phase lagging model of heat and moisture transfer has been developed in an infinite slab undergoing immersion frying of foods. This model is a moving boundary problem of a system of second order hyperbolic partial differential equations. The solution obtained by using finite element Legendre wavelet Galerkin scheme. The stability analysis of present model and method are discussed in detailed and whole analysis presented in dimensionless form. The effect of variability of Luikov number, Kossovich number and Biot number on frying process are discussed in detail.

Evaluation of quality of Argentinean sunflower oil used in high-moisture food frying

Objective: To make evaluation of quality of Argentinean sunflower oil used in high-moisture food frying through parameters indicators of oil deterioration. Methods: The results were obtained after studying the effect of temperature-time and the type of food subjected to frying through Total Polar Compounds (TPCs) determination. The type of food selected was breaded food and potato chips. From calorimetric analysis (DSC) of frying oil was obtained crystallization temperature and the crystallization enthalpy. Also was determining fatty acid composition of the frying oil by gas chromatography. Findings: It was observed during the oil heating test at various times, that the TPC content increased over time. The highest the temperatures were, the most distinctive the rises were. During the frying of breaded food and potato chips the deterioration of the oil was accelerated, observing the greatest deterioration after the breaded frying process. The thermo grams obtained by DSC showed a well-defined crystallization peak that when heating treatment times were increased, it reflected in lower temperatures and a decrease in enthalpy. A high correlation was found between the concentration of total polar compounds, and the parameters obtained from thermo grams and the concentration of palmitic and linoleic acids. Novelty/Improvement: The results obtained provide useful information for food quality control in order to avoid variations of the sensory and nutritional characteristics of sunflower oil used in high-moisture food frying. Keywords: Frying, High-Moisture Food, Oil, Quality, Total Polar Compounds

Analysis of fatty acid profiles of free fatty acids generated in deep-frying process.

During the deep fat food frying process, the frying media, oil, continuously degenerates when exposed to high temperature, oxygen and moisture. This leads to physical and chemical changes including the formation of hydrolysis products such as free fatty acids (FFAs) which are associated with undesirable darkening in colour, off-flavouring and a lowering of the smoke point. This study was aiming to develop a method capable of identifying and quantifying individual free fatty acids within oil using a small sample size (100mg of oil). We used liquid/liquid extraction technique to separate FFAs from the rest of the oil followed by esterification using boron trifluoride (BF3) and then gas chromatography analysis. Various extraction conditions were tested. A mixture of 0.02M phosphate buffer at pH 12 and acetonitrile at solvent: buffer ratio larger than 2:1 showed the highest efficiency in extraction of FFAs. The method was capable of producing accurate fatty acid profiles of FFAs and showed good precision on medium rancidity oil samples. It also captured the differences induced by adding free fatty acids to samples. An interesting discrepancy was found between the new method and the traditional titration method in terms of overall FFA content, which suggests further optimisation and investigation are required.

Verification of hybrid mixture theory based two-scale unsaturated transport processes using controlled frying experiments

Involvement of unsaturated transport and high temperatures during frying of foods makes it a challenging process to study via experiments and computer simulations. The objective of this research is to validate the hybrid mixture based unsaturated transport theory of Takhar (2014) via controlled frying experiments. A hollow Teflon disc is used to insulate the edges of potato disc to ensure that frying is controlled, one-dimensional, and oil uptake and moisture loss happen only through top and bottom surfaces. The model was used to predict moisture and oil content, evaporation rates, temperature distribution, and pore and gas pressure profiles as a function of frying time and temperature. Percentage average absolute difference (AAD) between predicted and experimental values for moisture content was 3.89%, 5.7% and 5.5% and oil content was 14%, 31% and 20% at 150, 170 and 190°C respectively. Simulations showed that oil penetrated to only 0.5mm into the potato disc. Removal of surface oil improved the prediction of experimental oil content. Maximum evaporation rate of 0.13kg/m3s was observed near the surface of potato slice at 150s frying time resulting in rapid moisture loss. Pore pressure remained negative beyond 90s frying time, which may act as a driving force for oil uptake.

Penerapan Inovasi Teknologi Mesin Penggorengan Vakum dan Pelatihan Olahan Kripik Buah di Kelompok Usaha Bersama(Kub) Ayu di Kelurahan Kranjingan Kecamatan Sumbersari Kabupaten Jember

The objective of Community Service Scheme Program for Community in KUB Ayu Kelurahan Kranjingan is to assist partner business groups in their efforts to improve partner productivity through the application of appropriate technology and business management training. Problems related to the production process faced by partners are 1) food frying is still done by traditional way, and 2) Partners difficulty in managing financial administration, management of raw material stock control, management of stock control of finished material. Motode in the manufacture of vacuum frying machine (Vacuum Frying Machine) begins with the process of planning, manufacturing, testing, and training the use of machinery for members of partners. The implementation method consists of 4 stages, the first coordination and socialization of the activity plan, the two identification and validation of partnerproblems, the three design, assembly, and field test of equipment and machinery according to the needs of partner technology, the four counseling and mentoring. The result of Community Science and Community Service program can realize the implementation of vacuum fryer machine with specification of raw material capacity 3 kg / process, LPG fuel with automatic temperature control, water circulation coolant, cooking oil volume: 35 liters, power requirement 900 watt, 180 dimension X 120 x 120 cm, with an oil heating temperature range of 80 0C to 87 0C. The frying time ranges from 90-120 minutes. Variations of chips raw materials include; Jackfruit, pineapple, with depreciation rates of 70%, 60% and 80%, respectively. Training of financial administration management skills, management of raw material stocks, management of finished material stock control has brought social and economic impact to KUB Ayu's partners. Keyword : Training of fruit chips, Vacuum Frying Machine, KUB Ayu.

Reducing the Formation of Acrolein from Linolenate-Rich Oil by Blending with Extra Virgin Olive Oil during Repeated Frying of Food at High Temperatures

Vegetable oils have long been used in cooking. However, repeated heating at a high temperature results in the gradual deterioration of the vegetable oils through oxidative degradation of fatty acids, leading to the formation of undesirable and irritating odors (e.g., acrolein). Linolenic acid is the main source of the acrolein formed during the heating of vegetable oils. The present study has developed a method to reduce the formation of acrolein during repeated frying with vegetable oils. Electronic nose analysis showed that the formation of acrolein from low-linolenic oil such as extra virgin olive oil (EVOO) was much lower than from a linolenic-rich oil, salad oil, when frying French fries. Blending EVOO with salad oil effectively reduced the amount of acrolein formed during repeated frying. These results suggest that EVOO can be used to reduce the formation of acrolein when repeatedly heating foods in thermosensitive vegetable oils.

Dietary Habits and Cooking Methods Could Reduce Avoidable Exposure to PCBs in Maternal and Cord Sera

Polychlorinated biphenyls (PCBs), like other persistent organic pollutants, are accumulating throughout the food chain and pose health threats to humans, especially children and foetuses. There is no protocol for reducing the contamination levels of the PCBs in humans. This study identified food items and cooking methods that reduce serum PCB levels by analysing data collected from the Chiba Study of Mother and Child Health. The sample size was 194 subjects. Serum PCB levels were measured using gas chromatography–electron capture negative ionization quadrupole mass spectrometry. Information on dietary habits was obtained from a brief diet history questionnaire that included questions about food items and cooking methods. Food items were categorized into food groups, and nutrient levels were calculated based on food item consumption. Principal component analysis and lasso regression were used as statistical methods. The analyses of food items and nutrients suggested that food items rich in dietary fibre reduce avoidable exposure to PCBs, as could grilling and deep frying of food, which could reduce avoidable exposure to serum PCBs in mothers and foetuses. (174 words).

Evaluation of the quality of sunflower oil subjected to frying processes under controlled conditions

The food frying process causes physicochemical modifications in the oils, affecting their sensorial characteristics and eventually producing toxic effects. The objective of this work was to study the degradation of sunflower oil used in potato immersion frying, considering the free fatty acid content, peroxide index and refractive index, high­lighting the critical and optimal points of the process. Experimental planning and response surfaces were used, considering the variables temperature, total process time and potato:oil ratio. The three variables showed a sig­nificant linear effect on the percentage of free fatty acids (R² = 98.3%). The value of the peroxide index was strongly influenced by temperature and, to a lesser extent, by other variables (R² = 98%). The refractive index was influenced linearly and quadratically by time and temperature and only linearly by the potato:oil ratio (R² = 97.2%). These results indicate that frying processes conducted at warmer temperatures may increase the useful life of the oil, whose characteristics directly influence the quality of the final product.

Status of the bioactive phytoceuticals during deep-fat frying of snack food using nutra-coconut oil

The present study was carried out to study the physico-chemical changes that take place in both product and oil during the deep fat frying of a traditional savoury snack 'kodubale', at 120-160 °C for 120-600 s using coconut oil (CO) and nutra-coconut oil (NCO). Further, kinetic studies on moisture loss, oil uptake, color and degradation of β-carotene, total polyphenol content and antioxidant activity for kodubale was carried out during frying as a function of temperature and time. The study showed that the kinetic coefficients for above parameters increased with temperature and time and the data obtained were well fitted with first order kinetic model. The results also revealed that NCO fried product retained major phenolic acids due to the presence of antioxidants in the NCO which was enriched with flaxseed oil concentrate. The fatty acids profile of oil extracted from products obtained by frying using NCO was characterized with higher ω-3 and ω-6 fatty acids content as compared to same obtained using CO. However, the breaking strength and sensory characteristics of CO and NCO fried kodubale was found to have no significant difference (p<0.05).

Deterioration of Extra Virgin Olive Oil Caused by Different Processes

Extra virgin olive oil is recognized as a very stable oil because of its composition in fatty acids and its content in natural antioxidants (tocopherols and polyphenols). In the bibliography are works that address different aspects of this stability, from the duration of its useful life to its performance in the frying of foods. Some works also link their stability with the content of natural antioxidants. For example, Franco et al. (2014) studied the content of phenols and their antioxidant capacity in olive oils of seven different varieties. Baccouri et al. (2008) found a good correlation between the oxidative stability (measured in Rancimat) of the oils studied and the concentration of total phenols and tocopherols.

Application of Vacuum Frying as a Furan and Acrylamide Mitigation Technology in Potato Chips

Consumers like fried snacks, and taste, color, and texture are key aspects in their preference. However, during frying of foods some toxic compounds, such as furan and acrylamide, are produced. The objective of this work was to mitigate furan and acrylamide formation in potato chips, without affecting their main quality attributes, by using vacuum frying. To accomplish this purpose, potato slices were fried at atmospheric (P abs 29.92 inHg) and vacuum conditions (P abs 3.00 inHg), using equivalent thermal driving forces (T water boiling point − T oil = 50, 60, or 70 °C). Furan and acrylamide concentration, oil content, and texture of both atmospheric and vacuum-fried samples were determined. Vacuum-fried potato chips showed reductions of about 81, 58, and 28% of furan, acrylamide, and oil content, respectively, when compared to their atmospheric counterparts. Additionally, the texture was not affected (p > 0.05) by changes in the pressure during frying. Results clearly showed that vacuum frying is an effective technology for furan and acrylamide mitigation in potato chips, since it reduces the content of both contaminants and preserves the quality attributes of fried snacks.

Effects of ultrasound pretreatments on the kinetics of moisture loss and oil uptake during deep fat frying of sweet potato ( Ipomea batatas )

Abstract The possibility of ultrasound assisted pretreatments of sweet potato to lower the moisture content and oil uptake during deep fat frying and its effects on the mass transfer rate was investigated. Sweet potato samples prior to frying were immersed in distilled water with ultrasound (UD), osmotic dehydration without ultrasound (OD) and ultrasound assisted osmotic dehydration (UOD). Ultrasound probe having frequency of 28 kHz at 300 W maximum power and time of 30 min was used for the pretreatment. The control (without pretreatment) and the pretreated samples were fried using sunflower oil at temperature of 130, 150 and 170 °C for 2, 4, 6, 8 and 10 min. The first order kinetic model was used for the mass transfer rate for moisture loss and oil uptake. The lowest moisture content was found in fried samples pretreated in UOD and OD while the lowest oil uptake was obtained in fried samples pretreated in UD having 65.11 and 71.47% oil reduction at temperature of 150 and 170 °C, respectively, compared to the untreated sample. The k values of all pretreated samples were higher than that of the untreated at 150 and 170 °C. The highest activation energy for moisture loss was found in untreated samples while the lowest activation energy for oil uptake was found in samples pretreated in UOD. The results from this work proved that ultrasound is a good pretreatment that can be used to obtain a low moisture content and oil uptake during deep fat frying of sweet potato. Industrial relevance Ultrasound is a novel technology that is widely used in the food industries because of its numerous advantages over conventional methods. Its application in the frying of foods could also help in the reduction of oil uptake, thus making safe the consumption of fried foods. The information about frying kinetics could also help in the design and optimization of the process in the food industry.

Frying of Food: A Critical Review

ABSTRACTDeep fat fried foods are very popular food because of their unique quality characteristics. The process is based on the immersing food at high temperatures, depending on the raw materials, thereby leading to physical and chemical changes such as starch gelatinization, protein denaturation browning, and crust formation. In order to obtain a product with a low fat content, it is essential to understand the mechanisms involved during the frying process so that oil migration into a food product can be minimized. The purpose of this study is to review literature findings on frying of food. The review also aims to draw the attention of stakeholders, including decision makers, on the need to assess the health risks associated with consumption of fried food product and, consequently, the necessary measures and steps to reduce such risks in order to have safer food in the world.

Acrolein Can Cause Cardiovascular Disease: A Review

Acrolein is a highly reactive unsaturated aldehyde that is formed during the burning of gasoline and diesel fuels, cigarettes, woods and plastics. In addition, acrolein is generated during the cooking or frying of food with fats or oils. Acrolein is also used in the synthesis of many organic chemicals and as a biocide in agricultural and industrial water supply systems. The total emissions of acrolein in the United States from all sources are estimated to be 62,660tons/year. Acrolein is classified by the Environmental Protection Agency as a high-priority air and water toxicant. Acrolein can exert toxic effects following inhalation, ingestion, and dermal exposures that are dose dependent. Cardiovascular tissues are particularly sensitive to the toxic effects of acrolein based primarily on in vitro and in vivo studies. Acrolein can generate free oxygen radical stress in the heart, decrease endothelial nitric oxide synthase phosphorylation and nitric oxide formation, form cytoplasmic and nuclear protein adducts with myocyte and vascular endothelial cell proteins and cause vasospasm. In this manner, chronic exposure to acrolein can cause myocyte dysfunction, myocyte necrosis and apoptosis and ultimately lead to cardiomyopathy and cardiac failure. Epidemiological studies of acrolein exposure and toxicity should be developed and treatment strategies devised that prevent or significantly limit acrolein cardiovascular toxicity.

Quality assessment of mustard oil in deep fat frying

Now a days fried foods are very common everywhere around the world and it can be observed by the increasing number of fast food restaurants in the last few decades. Deep frying of foods at high temperature enhances the sensorial properties which include the unique fried flavor, golden brown colour and crispy texture. At the same time, so many chemical reactions like oxidation, polymerization, hydrolysis, etc., take place in the food system, which ultimately alters the physical and chemical properties of fat. Mustard oil is a vegetable oil which is widely being used in India for cooking purpose. The parameters like free fatty acid (FFA), peroxide value (PV), p-anisidine value (p-AV), total oxidation (TOTOX value), iodine value (IV) and colour are studied in this experiment. The heating oil parameter has been taken in such a way, considering the frying practices done in the restaurants of North-East India. The oil sample was taken after every 5 hours of heating mustard oil in deep fat fryer. The 30 hours of heating (5h/day) degrades mustard oil to such an extent that it becomes unadvisable for human consumption. The study showed that there is ample change in the chemical composition and the hunter colour showed that the oil has lost its luster and has become dark red.

Microstructural Characterization of Fried Potato Disks Using X-Ray Micro Computed Tomography.

Microstructural properties play a key role to affect oil uptake and product quality during frying of foods. The objective of this study was to observe the complex microstructural changes and mass transfer mechanisms in potato disks during frying. The potato disks of 1.65 mm thickness were fried at 190 °C for 0, 20, 40, 60, and 80 s. X-ray micro-computed tomography (CT) was used for 3-dimensional (3D) imaging of microstructure of porous potato disks. Total porosity, pore size distribution, oil content, and air content of potato disks were calculated from resulting 3D data sets. Oil and air content measured by analysis of micro-CT images followed trends similar to Soxtec and gas pycnometry methods, respectively. Image analysis showed a significant change in pore size distribution as a function of frying time. Frying time was also observed to have an effect on tortuosity, which is an important microstructural fluid transport property. Tortuosity was measured by path length ratio method from 3D data sets obtained from image analysis. A linear inverse relationship was observed between porosity and tortuosity where tortuosity decreased with the increase of porosity. It was also observed that during frying, oil content increased with the decrease of tortuosity. This phenomenon indicated that the lower tortuosity created a less complicated and sinuous path, thus resulting in less resistance to oil penetration. Micro-CT technique can serve as an effective tool for elucidating microstructure of fried foods, and can provide complementary information to conventional lab techniques.

Physio-Chemical Changes During Repeated Frying of Cooked Oil: A Review

Today, fried foods are very famous everywhere around the world and it can be observed by the increasing number of fast food restaurants in the last few decades. Deep frying of foods at high temperature enhances the sensorial properties which include the unique fried flavor, golden brown color and crispy texture. Chemical reactions like oxidation, polymerization, hydrolysis, etc., take place in the food system, which ultimately alters the physical and chemical properties of fat. Consequently, so many by-products such as free fatty acids, alcohols, cyclic compounds, dimers and polymers are produced. Therefore, it is necessary to understand the physical and chemical changes during deep fat frying to monitor the quality of fried foods. In this review, we constituted the previous studies on the changes in fats during frying and methods used to analyze the quality of fried oil, in order to explore the areas which require further research. Practical Applications Deep frying is the most common and one of the oldest methods of food preparation worldwide. To reduce the expenses, the oil tends to be used repeatedly for frying. Repeated use of this oil has become a common practice due to low level of awareness among the public about the bad effect of this practice. Nowadays, the consumption of deep-fried food has gained popularity which may cause increased risk of obesity. When heated repeatedly, changes in physical appearance of the oil will occur such as increased viscosity and darkening in color, which may alter the fatty acid composition of the oil. In this review, we have investigated the detail mechanism of decay of oil and parameters to be measured to know the quality and safety of oil.