Understanding the Frying Process of Plant-Based Foods Pretreated with Pulsed Electric Fields Using Frying Models

Pulsed Electric Field Treatment of Sweet Potatoes to Reduce Oil and Acrylamide in Kettle Chips

The purpose of this investigation was to utilize pulsed electric field (PEF) technology to make sweet potato kettle chips (SPKC) healthier by lowering the amount of oil absorbed and reducing the amount of acrylamide formed during frying. Sweet potatoes were treated continuously in an Elea PEF Advantage Belt One system and prepared as SPKC, without peeling and sliced to a thickness of 1.7 mm. The specific energy for PEF application was set to either low (1.5 kJ/kg) or high (3.0 kJ/kg) with a field strength of 1.0 kV/cm and a pulse width of 6 μm. Batches of 500 g unrinsed potato slices were fried in canola oil at 130 °C for 360 s. The oil content in 3.0 g of fried SPKC was 1.39 g or 46.3%, whereas the oil content was 37.9% for high and 37.7% for low PEF-treatment conditions. Acrylamide (AA) in the fried SPKC was quantified by mass spectrometry to be 0.668 μg/g in the non-PEF control and 0.498 μg/g for low and 0.370 μg/g for high PEF treatment. The results of this study support the use of PEF in SPKC processing to reduce oil absorbance during frying by up to 9% and lower AA by up to 45%.

Optimization of the Frying Process for Maximizing Crispiness of Scallop (Patinopecten yessoensis) Adductor Muscle Snacks Using Vacuum Low-Temperature Frying

Scallops, an economically important seafood, are popular as fried snacks. Vacuum low-temperature frying creates crispy, healthier foods that meet consumer demand for nutritious snacks with excellent texture. However, research on vacuum frying for shellfish products remains limited. This study aimed to optimize the process for developing a healthy, crispy snack that retains the original shape of the Yesso scallop (Patinopecten yessoensis) adductor muscle using vacuum low-temperature frying technology. The effects of various frying methods on the scallops were analyzed. The vacuum low-temperature frying process was optimized based on evaluations of physical, chemical, and sensory properties. Frying conditions were optimized using response surface methodology, with temperature (X1: 90.1-109.9 °C) and time (X2: 186-774 s) as variables. Based on moisture (5.6 ± 0.1 g/100 g), hardness (1470 ± 5.0 g/cm2), and sensory chewiness (7.6 ± 0.2 points) analyses, 99.9 °C and 480 s were identified as the optimal conditions. Validation was conducted through sensory evaluation by 30 trained panelists. Scallops produced under these optimal frying conditions exhibited low water activity (aw) (0.46), desirable texture (1428 g/cm2), palatability (7.9 points), and high protein content (45.6 g/100 g). The predicted and experimental values for frying temperature and time showed strong agreement, validating the reliability of the optimization model.

Effect of different pre-treatment on acrylamide content, nutrition value, starch digestibility and anthocyanin bioaccessibility of purple sweet potato (Ipomoea batata) deep-fried chips

Veggie chips have gained popularity in the European market. These are considered healthier than potato chips by consumers. However, few works evaluate their nutritional and digestibility. The current work aimed to evaluate the effect of four pre-frying treatments (soaking, blanching, pulsed electric field (PEF) and PEF + blanching combination (PEFB)) on the chemical composition, anthocyanins, acrylamide, and digestive behavior (starch hydrolysis and anthocyanins bioaccessibility) of purple sweet potato deep-fried chips. In total 15 independent batches were made, three for each studied treatment (also a control without pretreatment was developed). The studied pretreatments impacted on fat and starch content, especially blanching and PEFB, which caused an increase in fat absorption and break starch, generating maltodextrins. Nineteen anthocyanins were detected, mainly cyanidin and peonidin derivatives, but a drastic loss was observed in blanched, PEF-treated and PEF-B-Treated chips. Acrylamide values ranged from 504.11 to 6350.0- μg/kg, with the highest values reported by untreated chips and the lowest by PEF-B-treated chips (p < 0.05). The anthocyanin's bioaccessibility ranged between 66.57 and 92.88%, with soaked chips that showed the highest values.

Study on quality characteristics, shelf-life prediction and frying mass transfer of breaded tilapia nuggets

Deep-fried breaded tilapia nuggets (DFBTNs) have good market prospects as a tilapia deep-processed product. In this study, we used pre-optimized DFBTNs to simulate the mass change from storage to consumption and investigated the changes in storage shelf-life and frying mass transfer kinetics of DFBTNs. Microbial growth trend and shelf-life prediction models at different storage temperatures were developed using a modified Gompertz equation. The R2 of the fitted equations were all greater than 0.98, and the predicted shelf-life of the products was close to the actual measurement time. The ability of the electronic nose and tongue to differentiate between odor and taste can be used as a secondary indicator to determine whether a product is spoiled or not. During the reheating process of deep-frying, the batter shell moisture decreased (18.69 %→6.89 %), and the oil content increased (2.76 %→27.35 %). The mass transfer coefficient k fitted by Fick's second law for moisture evaporation was 0.0086, and the mass transfer coefficient k fitted by the first-order kinetic equation for oil absorption was 0.1137. This study is informative for storing and consuming DFBTNs, which can provide a basis for the deep processing and high-value utilization of tilapia.

Formation of pores and bubbles and their impacts on the quality attributes of processed foods: A review

Pores and bubbles significantly influence the physical attributes (like texture, density, and structural integrity), organoleptic properties, and shelf life of processed foods. Hence, the quality of foods and their acceptance by the consumers could be influenced by the properties and prevalence of pores and bubbles within the food structure. Considering the importance of pores, this review aimed to comprehensively discuss the factors and mechanisms involved in the generation of pores and bubbles during the processing of different food products. Moreover, the characteristics and effects of pores on the properties of chocolates, cheeses, cereal-based foods (like cake, puffed grains, and pasta), dried, and fried products were discussed. The impacts of bubbles on the quality of foam-based products, foam creamers, and beverages were also explored. This review concludes that intrinsic factors (like food compositions, initial moisture content, and porosity) and extrinsic factors (like applied technologies, processing, and storage conditions) affect various properties of the pores and bubbles including their number, size, orientation, and distribution. These factors collectively shape the overall structure and quality of processed food products such as density, texture (hardness, cohesiveness, chewiness), and water holding capacity. The desirability or undesirability of pores and their characteristics depends on the type of products; hence, some practical hints were provided to mitigate their adverse effects or to enhance their formation in foods. For example, pores could increase the nutrient digestion and reduce the shelf life of the products by enhancing the risk of fat oxidation and microbial growth. In conclusion, this study provides a valuable resource for food scientists and industry professionals by discussing the effects of pores on food preservation, heat, and mass transfer (including oxygen, moisture, flavors, and nutrients). Understanding the dynamic changes in porosity during processing will be effective in customization of final product quality with desired attributes, ensuring tailored outcomes for specific applications.

Enhanced Frying Efficiency at Low Temperatures Utilizing a Novel Planetary Fryer

This study aims to optimize the frying process of natural porous materials (like potatoes) by enhancing heat and mass transfer phenomena through significant horizontal acceleration values following a spatially periodic pattern that alternates the intensity of inertia forces uniformly across the frying vessel. The generated horizontal inertial forces act complementary to the normal vertical buoyancy force for the creation of agitating convective currents in the oil and for vapor bubbles' departure from the surface of frying objects. The use of an innovative frying device, employing simultaneous rotation around two vertical axes at a different speed in a so-called planetary type of motion, serves to facilitate this production of horizontal acceleration values that allows intensifying the performance of frying. The present investigation examines the impact of rotational speed, along with oil temperature and frying duration, on the water loss and sensory evaluation of fried items. The potato-to-oil ratios typically found in industrial frying operations are employed. The intended outcome is a more energy-efficient frying process, reduced cooking times, and a healthier product due to lower frying temperatures and the consequent decreased formation of harmful compounds. This approach carries substantial implications for food processing, potentially enhancing productivity while limiting operational costs.

Pulsed electric field effect on acrylamide reduction and quality attributes of continuous-style Lamoka potato chips

Potato chips are a popular snack, well-liked because of their texture-flavor combination. Potato chips are made by frying slices of potato in vegetable oil to achieve a crispy texture. Frying potato slices initiates the Maillard reaction, resulting in chemical changes that enhance taste, color, and texture, but also undesired acrylamides, which are suspected carcinogens. The application of pulsed electric field (PEF) technology is commonly used in French fry processing operations to prolong cutting blade sharpness and reduce waste, energy consumption, and water usage. Despite these attributes, PEF systems have not yet gained widespread adoption by potato chip producers. In the current study, Lamoka potatoes were PEF-treated prior to continuous frying into potato chips. The effect of specific energy at 0.75 kJ/kg (Low-PEF) and 1.5 kJ/kg (High-PEF) and electric field strength of 1 kV/cm, frequency of 24 kV, and pulse width of 6 μs versus untreated (control) samples was studied, then batches of 250 g of slices were fried at 170 °C or 185 °C for two frying times to obtain potato chips with acrylamide levels below the California Proposition 65 limit (275 ng/g). The Lamoka potato chip product quality metrics that were assessed include moisture, fat, reducing sugars, asparagine, acrylamide, chip color, and texture. PEF treatment of Lamoka potatoes resulted in chips fried in 10 % less time, lower oil content by 8 %, and a decrease of reducing sugars by 19.2 %, asparagine by 42.0 %, and acrylamide by 28.9 %. The PEF fried chips were lighter in color but maintained textural attributes compared to continuous frying cooking. The process of frying potato slices at 170 °C for 150 s with High-PEF yielded potato chips with acrylamide content below the California Proposition 65 limit; which speaks to the health implications for consumers and the quality and safety of these chips.

Changes in food quality and characterization under thermal accumulation conditions during Chinese cooking

Chinese cooking is the primary treatment method for table food in China. The process is complex and large-scale, which is important to the macroeconomy and national nutrition and health. First, this article puts forward the concept of thermal accumulation for Chinese cooking by taking pork tenderloin fried at different oil temperatures, explaining changes in moisture content, hardness, and color with different thermal accumulation conditions, and measuring kinetic parameters. The variations of L* and b* obtained by the experimental results belong to the first-order reaction kinetic model, while the changes in water content and shear force belong to the zero-order reaction kinetic model. Simultaneously, the superheat value is used as a thermal accumulation indicator, combined with sensory evaluation to determine that the Z value of the human sensory overheating of pork tenderloin is 99°C, and O s,max (Z = 99°C, the reference temperature is 110°C) is 5.86 min.

Oil Frying Processes and Alternative Flour Coatings: Physicochemical, Nutritional, and Sensory Parameters of Meat Products

The frying process changes can be desirable and undesirable, involving the physicochemical, nutritional, and sensory aspects, depending on the food and oil properties and the frying process. In this context, alternative flours emerge as a strategy for adding value to the food since they are rich in fiber, vitamins, and minerals, contributing to the variability of ingredients and the full use of food, including residues such as seeds and husks. This narrative review aims to gather current scientific data addressing the alternative flour coatings on breaded meat, mainly chicken, products to evaluate the effects on fried products' nutritional value, physicochemical parameters, and sensory attributes. Scopus, Science Direct, Springer, and Web of Science search bases were used. This review showed that alternative flours (from cereals, legumes, fruits, and vegetables) used as coatings increase water retention and reduce oil absorption during frying, increase fibers and micronutrient content, which are not present in sufficient quantities in commonly used flours due to the refining process. These flours also reduce gluten consumption by sensitive individuals in addition to favoring the development of desirable sensory characteristics to attract consumers. Therefore, frying processes in oil promote a reduction in humidity, an increase in oil absorption and energy content, and a decrease in vitamin content. In this context, coatings based on alternative flours can reduce these adverse effects of the frying process.

Expanded porous-starch matrix as an alternative to porous starch granule: Present status, challenges, and future prospects

Exposing the hydrated-soft-starch matrix of intact grain or reconstituted flour dough to a high-temperature-short-time (HTST) leads to rapid vapor generation that facilitates high-pressure build-up in its elastic matrix linked to large deformation and expansion. The expanded starch matrix at high temperatures dries up quickly by flash vaporization of water, which causes loss of its structural flexibility and imparts a porous and rigid structure of the expanded porous starch matrix (EPSM). EPSM, with abundant pores in its construction, offers adsorptive effectiveness, solubility, swelling ability, mechanical strength, and thermal stability. It can be a sustainable and easy-to-construct alternative to porous starch (PS) in food and pharmaceutical applications. This review is a comparative study of PS and EPSM on their preparation methods, structure, and physicochemical properties, finding compatibility and addressing challenges in recommending EPSM as an alternative to PS in adsorbing, dispersing, stabilizing, and delivering active ingredients in a controlled and efficient way.

Dynamic changes in the water and volatile compounds of chicken breast during the frying process

The influence of frying times (0, 2, 4, 6, 8, and 10 min) on the continuous changes in the water distribution and the concentrations of key volatile compounds in chicken breast during the frying process were studied. The fried chicken samples could be distinguished by PCA of E-nose and PLS-DA of GC-MS. A total of 40 volatile compounds were identified by GC-MS, and 28 compounds were verified to be the key compounds after further screening by OAVs. The T22 was increased first and then decreased, while the M22 and M23 in fried chicken were considerably decreased and increased with increasing frying time, respectively. The content of the water and the total peak area of LF-NMR in fried chicken samples during the frying process significantly decreased, and the water was transferred from high to low degrees of freedom. In addition, water content, T21, T22, M22 and L* value were positively correlated with most alcohols and aldehydes, and were negatively correlated with pyrazines, while a*, b*, M23 and all amino acids were positively correlated with pyrazines and were negatively correlated with most alcohols and aldehydes. The results may guide the production processes of fried chicken and help produce high-quality chicken products.

A review on the frying process: Methods, models and their mechanism and application in the food industry

Frying is one of the most popular and traditional processes used in the food industry and food services to manufacture products that are high in quality and with unique sensory characteristics. The most common method of frying is deep-fat frying, used worldwide due to its distinct flavor profile and sensory aspects, which leads to physio-chemical changes at both macro and micro levels. One of the major concerns with deep-fried foods is their high oil content, and a variety of metabolic disorders can be caused by overconsumption of these foods, including heart disease, obesity, and high cholesterol. Due to their enticing organoleptic properties with their delicious flavor, pleasing mouthfeel, and unique taste, making them irresistible, it is also responsible for undesirable and unacceptable characteristics for consumers. Oil absorption can be reduced by developing novel frying methods that limit the amount of oil in products, producing products with fewer calories and oil while maintaining similar quality, flavor, and edibility. In addition, different pretreatments and post-frying treatments are applied to achieve a synergistic effect. The transfer of mass and heat occurs simultaneously during frying, which helps to understand the mechanism of oil absorption in fried food. Researchers have discovered that prolonged heating of oils results in polar compounds such as polymers, dimers, free fatty acids, and acrylamide, which can alter metabolism and cause cancer. To reduce the oil content in fried food, innovative frying methods have been developed without compromising its quality which also has improved their effect on human health, product quality, and energy efficiency. The aim is to replace the conventional frying process with novel frying methods that offer fried food-like properties, higher nutritional value, and ease of use by replacing the conventional frying process. In the future, it might be possible to optimize frying technologies to substantially reduce fried foods' oil content. This review focuses on a detailed understanding of different frying techniques and attempts to focus on innovative frying techniques such as vacuum frying, microwave cooking, and hot-air frying that have shown a better potential to be used as an alternative to traditional frying.

Structure and Texture Characteristics of Novel Snacks Expanded by Various Methods

The aim of this work was to evaluate the structure of novel potato-based snack foods supplemented with various levels of fresh carrot pulp by using X-ray micro-computed tomography, texture profile, and sensory analysis. Three different methods of extruded snack pellets expansion were used to obtain ready-to-eat crisps: deep-fat frying, microwave, and hot-air toasting. The obtained results revealed that the pellets expansion method affected the porosity, size of pores and wall thickness, texture properties, and notes of sensory analyses of the obtained crisps. Deep-fat frying had a similar influence to microwave heating on ready-to-eat crisps properties, and both methods were significantly different in comparison to hot-air toasting. Crisps based on snack pellets supplemented with the addition of fresh carrot pulp in the amount of 10 to 30% expansion through hot-air heating showed unsatisfactory expansion and texture, but it is highly advisable to use deep-fat frying and microwave heating to achieve attractive potato-carrot crisps.

Effect of moderate electric field voltage on the quality and heat transfer characteristics of potato strips during deep-frying process

The application of moderate electric field (MEF) on frying can influence the quality of fried products; however, the associated mechanism is unknown. This study investigated the effects of MEF voltage on the quality and surface heat transfer of potato strips fried with an MEF. With increasing MEF voltage, the moisture content, hardness, starch gelatinization rate, and shrinkage of the potato strips significantly increased (p < 0.05), while their oil content and brightness decreased (p < 0.05). The decrease in their oil content and brightness indicated improved crust formation, which reduced oil absorption. The potato strips fried under higher voltages exhibited lower oil contents and better microstructure than those fried under lower voltages. A possible mechanism comprised MEF increasing the heat transfer coefficient (h) between oil and potato strips, thereby accelerating crust formation; moreover, h values increased with MEF voltage. The results indicate the potential application of MEF in food frying.

Reduction of oil uptake in vacuum fried Pleurotus eryngii chips via ultrasound assisted pretreatment

The reduction of oil uptake in vacuum-fried Pleurotus eryngii chips by ultrasound assisted pretreatment was investigated regarding the pore structure changes. Pore structure of P. eryngii chips with four pretreatments, such as blanching, blanching + osmosis, blanching + ultrasound and blanching + ultrasound assisted osmosis was determined by mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM). In addition, the quality parameters of vacuum-fried P. eryngii chips such as hardness, rehydration ratio, reducing sugar, protein and oil content were also measured. The results showed that the oil absorption of vacuum fried P. eryngii chips was affected by the porous structure. The oil content of vacuum fried P. eryngii chips was significantly and positively correlated with the pores with diameters above 50, 5–50, and 0.5–5 μm in the samples both before and after vacuum frying, while negatively correlated with the pores with diameters below 0.5 μm. Ultrasound pretreatment changed the microporous structure of P. eryngii chips, effectively hindering the oil absorption of samples. In particular, ultrasound assisted osmosis pretreatment induced the formation of more micropores. It was concluded that blanching + ultrasound assisted osmosis pretreatment is a promising method to reduce oil absorption and improve the quality of vacuum fried foods.

Optimization of the frying process in relation to quality characteristics of Khaja (A traditional sweet)

The present study was focused on the optimization of process parameters and quality characterization of Khaja. A full factorial design 53 was applied using different levels of fat proportions (5-25%), frying temperature (160-200 °C), and frying time (1-5 min). The response optimizer function in Minitab 18 software was used to select five samples with the highest desirability which were then subjected to sensory analysis. The lightness of the samples decreased significantly (P ˂ 0.05) from 68.59 to 43.33 whereas, redness increased significantly (P ˂ 0.05) from 0.26 to 11.48 with increasing levels of all independent variables. Water activity and moisture content of the samples decreased significantly (P ˂ 0.05) from 0.75 to 0.21 and 14.41-1.40%wb respectively, whereas total fat content increased significantly (P ˂ 0.05) from 25.05 to 45.7% with increasing levels of independent variables. The hardness of the samples significantly (P ˂ 0.05) varied from 60.45 to 7.69 N. The sensory analysis revealed that the sample with 20% fat proportion, fried at 180 °C for 4 min, scored maximum in overall acceptability. The microstructural images revealed the structural damage and formation of pores in fried samples. The fatty acid analysis showed higher saturated fatty acids in market samples than in optimized samples. The results of the study concluded that fat proportion and frying parameters (temperature and time) are crucial for a better understanding of the deep-frying process of Khaja in order to achieve good quality.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05509-x.

Frying Time and Temperature Conditions’ Influences on Physicochemical, Texture, and Sensorial Quality Parameters of Barley-Soybean Chips

Demand for innovative healthy snacks that achieve consumer satisfaction represents increased interest for competitive food producers. The aim of this work was the assessment of physicochemical and sensory quality of barley-soybean chips involving legume protein flours by studying the effects of different substitution levels (10, 20, and 30%) of defatted soybean (DSB) flour, frying temperatures (150, 170, and 190°C), and frying times (60, 90, and 120 sec). The chips’ moisture content was significantly decreased with increased frying temperature and time. The moisture content (1.40%) was achieved at 10% DSB fried at 190°C for 120 sec. The least absorbed oil (29.25%) was achieved at the least substitution percentage (10% DSB), the least frying temperature (150°C), and the least frying time (60 sec). These results were reflected on sensorial parameters that revealed that the most preferred chips were barley-soybean chips with 10% DSB fried at 150 and 170°C. The amylose content was increased by 33.80% in chips substituted with 30% DSB, while it was decreased to 27.16% in chips substituted with 10% DSB, and vice versa for the amylopectin content. TPA revealed that DSB substitution levels were directly proportional with hardness and inversely proportional with elasticity and adhesiveness. From obtained results, substitution levels with 10% DSB fried at 150°C are recommended. These findings encourage the production of innovative enhanced snacks involving legume protein while maintaining consumer satisfaction.

Kinetics of Colour Development during Frying of Potato Pre-Treated with Pulsed Electric Fields and Blanching: Effect of Cultivar

The current research aimed to investigate the effect of pulsed electric fields (1 kV/cm; 50 and 150 kJ/kg) followed by blanching (3 min., 100 °C) on the colour development of potato slices during frying on a kinetic basis. Four potato cultivars 'Crop77', 'Moonlight', 'Nadine', and 'Russet Burbank' with different content of glucose and amino acids were used. Lightness (L* values from colorimeter measurement) was used as a parameter to assess the colour development during frying. The implementation of PEF and blanching as sequential pre-treatment prior to frying for all potato cultivars was found effective in improving their lightness in the fried products. PEF pre-treatment did not change the kinetics of L* reduction during frying (between 150 and 190 °C) which followed first-order reaction kinetics. The estimated reaction rate constant (k) and activation energy (E_a based on Arrhenius equation) for non-PEF and PEF-treated samples were cultivar dependent. The estimated E_a values during the frying of PEF-treated 'Russet Burbank' and 'Crop77' were significantly (p < 0.05) lower (up to 30%) than their non-PEF counterparts, indicating that the change in k value of L* became less temperature dependence during frying. This kinetic study is valuable to aid the optimisation of frying condition in deep-fried potato industries when PEF technology is implemented.

Heat and Mass Transfer Modeling to Predict Temperature Distribution during Potato Frying after Pre-Treatment with Pulsed Electric Field

Based on unsteady state heat conduction, a mathematical model has been developed to describe the simultaneous heat and moisture transfer during potato frying. For the first time, the equation was solved using both enthalpy and Variable Space Network (VSN) methods, based on a moving interface defined by the boiling temperature of water in a potato disc during frying. Two separate regions of the potato disc namely fried (crust) and unfried (core), were considered as heat transfer domains. A variable boiling temperature of the water in potato discs was required as an input parameter for the model as the water is evaporated during frying, resulting in an increase in the soluble solid concentration of the potato sample. Pulsed electric field (PEF) pretreatment prior to frying had no significant effect on the measured moisture content, thermal conductivity or frying time compared to potatoes that did not receive a PEF pretreatment. However, a PEF pretreatment at 1.1 kV/cm and 56 kJ/kg reduced the temperature variation in the experimentally measured potato center by up to 30%. The proposed heat and moisture transfer model based on unsteady state heat conduction successfully predicted the experimental measurements, especially when the equation was solved using the enthalpy method.

The biochemical changes in legumes during high-temperature micronization

The article considers the change in chemical and biological characteristics in some legumes grains, under conditions of high-temperature micronization with different moisture contents during heat treatment with infrared rays. The heat treatment of grains was carried out on a laboratory apparatus with a quartz radiant infrared panel. The temperature variation in the heat treatment zone occurred due to changing the distance between the panel and the surface of grains. The grain temperature was determined using a laser thermometer, and with a timer. To determine chemical and biological characteristics, we used a special optical density metering device. We have studied: 1. The dependence of starch content on the temperature in the changing initial moisture content. We found that after 30 seconds of high-temperature micronization of, “Tsanava“ beans at a grain moisture content of 12.7%, the starch content in the grain increases from 39.65% to 40.12%, then gradually decreases, and at 18.3% moisture content, it increases from 38.71% to 41.2%, with a moisture content of 28.6% it increases from 37.36% to 42.42%. Similar processes are also observed for the beans “field red“ and “white lupine“; 2. The dependence of glucose content on the temperature in the changing initial moisture content. As the mass fraction of starch decreases, the percentage of sugar (in terms of the equivalent amount of glucose) at a moisture content of 12.7% at the initial stage increases from 1.36% to 1.46%, and then the percentage of sugar increases relatively quickly to 1.64%, at a moisture content of 18.3% it increases from 1.3% to 1.38%, and then increases to 1.51, with a moisture content of 28.6%, it increases from 1.28% to 1.35% and then increases to 1.54. Similar processes are also observed for the beans “field red“ and “white lupine“.

The Impact of a Consecutive Process of Pulsed Electric Field, Sous-Vide Cooking, and Reheating on the Properties of Beef Semitendinosus Muscle

The effects of a consecutive process of pulsed electric field (PEF) treatment, sous-vide cooking, and reheating on the properties of beef semitendinosus muscle were investigated. Fresh meats were PEF-treated with different electric field strengths of 1.0, 1.5, and 2.0 kV/cm, and then the control and PEF-pretreated beef samples were sous-vide cooked at 60 °C for up to 24 h. The PEF pretreatment resulted in tenderization of the fresh meat proportional to the increase in the electric field strength. A significant decrease in cutting force (by 35%) was observed after PEF treatment at 2.0 kV/cm. The hardness and chewiness of the meat were also significantly reduced by PEF treatment. After sous-vide cooking, the PEF-pretreated samples exhibited a significantly reduced cutting force, redness value (a^*), and myoglobin content (mg/g) (p < 0.05). However, there were no significant differences in cooking loss and drip loss (p > 0.05). When the sous-vide-cooked meats were reheated in an oven (230 °C, 5 min), the reduced cutting force induced by the PEF pretreatment was retained.