Oil Uptake by Potato Chips or French Fries: A Review

The effect of cold atmospheric plasma pretreatment on oil absorption, acrylamide content and sensory characteristics of deep-fried potato strips

This study investigated the impact of 60 kV Cold Atmospheric Plasma (CAP) pretreatment for varying durations (5, 10, and 15 min) on potato strip characteristics before and after frying, emphasizing oil uptake, acrylamide formation. Potato samples treated with cap showed significantly better physicochemical characteristics. Scanning electron microscopy revealed deformation of cell wall due to CAP treatment. Fourier-transform infrared spectroscopy indicated structural changes, while X-ray diffraction analysis suggested that starch remained amorphous state in CAP-pretreated samples. Post-frying, CAP-treated potato strips exhibited altered oil distribution with reduced absorption, possibly due to microstructural changes. CAP substantially reduced acrylamide formation during frying by degrading asparagine and inactivating amylase. CAP affected strip color, with increased brightness and decreased redness and yellowness after 14 days. Sensory evaluation showed no significant difference, with prolonged CAP-treated strips receiving higher overall acceptability scores. These findings highlight CAP as a non-thermal technology to enhance fried potato product quality and safety.

Intelligence detection of oil absorption in French fries by surface profiles

Surface profiles are important evaluation indices for oil absorption behavior of fried foods. This research established two intelligent models of partial least-squares regression (PLSR) and back propagation artificial neural network (BP-ANN) for monitoring the oil absorption behavior of French fries based on the surface characteristics. Surface morphology and texture of French fries by rapeseed oil (RO) and high-oleic peanut oil (HOPO) at different temperatures were investigated. Results showed that oil content of samples increased with frying temperature, accounting for 37.7% and 41.4% of samples fried by RO and HOPO respectively. The increase of crust ratio, roughness and texture parameters (Fm, Nwr, fwr, Wc) and the decrease of uniformity were observed with the frying temperature. Coefficients of prediction set of PLSR and BP-ANN models were more than 0.93, which indicated that surface features combined with chemometrics were rapid and precise methods for determining the oil content of French fries.

A review of different frying oils and oleogels as alternative frying media for fat-uptake reduction in deep-fat fried foods

Purpose

This review aims to examine the potential of oleogels as a frying medium to decrease oil absorption during deep-frying and enhance the nutritional and energy content of foods. By investigating the factors influencing oil incorporation during deep-frying and examining the application of oleogels in this process, we seek to provide insights into using oleogels as an alternative to traditional cooking oils.

Scope

Deep-frying, a widely used cooking method, leads to the retention of large amounts of oil in fried food, which has been associated with health concerns. To address this issue, researchers have investigated various methods to minimize oil absorption during frying. One promising approach is the use of oleogels, which are thermo-reversible, three-dimensional gel networks formed by entrapment of bulk oil with a low concentration (<10% of weight) of solid lipid materials known as oleogelators. This review will focus on the following aspects: a) an overview of deep-fried foods, b) factors influencing oil uptake and underlying mechanisms for oil absorption during deep-frying, c) the characterization and application of different frying oils and their oleogels in deep-fried foods, d) components of the oleogel system for deep-frying, and e) the health impact, oxidative stability, and sensory acceptability of using oleogels in deep-frying.

Key findings

The review highlights the potential of oleogels as a promising alternative frying medium to reduce fat absorption in deep-fried foods. Considering the factors influencing oil uptake during deep-frying, as well as exploring the properties and applications of different frying oils and their oleogels, can result in improved product qualities and heightened consumer acceptance. Moreover, oleogels offer the advantage of lower fat content in fried products, addressing health concerns associated with traditional deep-frying methods. The capacity to enhance the nutritional and energy profile of foods while preserving sensory qualities and oxidative stability positions oleogels as a promising choice for upcoming food processing applications.

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.

Simultaneous mitigation of 3-monochloropropane 1,2 diol ester and glycidyl ester in edible oils: a review

The rising concern about the presence of 3-monochloropropane 1,2 diol ester (3-MCPDE) and glycidyl ester (GE) in food has prompted much research to be conducted. Some process modifications and the use of specific chemicals have been employed to mitigate both 3-MCPDE and GE. Alkalisation using NaOH, KOH, alkali metals or alkaline earth metals and post sparging with steam or ethanol and short path distillation have shown simultaneous mitigation of 51-91% in 3-MCPDE and of 13-99% in GE, both contaminants achieved below 1000 µg/kg. Some of the mitigation methods have resulted in undesirable deterioration in other parameters of the refined oil. When the processed oil is used in food processing, it results in changes to 3-MCPDE and GE. Repeated deep frying above 170 °C in the presence of NaCl and baking at 200 °C with flavouring (dried garlic and onion), resulted in increased 3-MCPDE. Repeated frying in the presence of antioxidants (TBHQ, rosemary and phenolics) decreased 3-MCPDE in processed food. The GE content in foods tends to decline with time, indicating instability of GE's epoxide ring.

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.

Identifying key factors and strategies for reducing oil content in fried instant noodles

Fried instant noodles have become a popular instant food in recent years, favored by consumers for their unique flavor and taste. Unfortunately, the oil content of instant noodles is generally high, so the rise of fat-related diseases poses a major health issue. From the perspective of the cost of instant noodle manufacturers and the health of consumers, it is of great significance to reduce the oil content of instant noodles. The aim of this review article is to provide an overview of the main factors, such as raw materials and production processes, affecting oil content in instant noodles in order to suggest specific strategies to reduce the oil content in the end product. From the literature reviewed, adding acetylated potato starch/carboxymethyl cellulose, hydroxypropyl methylcellulose, or preharvest-dropped apple powder in the noodle formulation could be a better choice to reduce oil uptake by 5%-20%. Instant noodles with lower oil content can be produced using novel alternative frying technologies, including microwave and vacuum frying. The proper management of the production processes and the implementation of enhancement strategies may result in a reduction of oil content in the end product.

Radio frequency as an innovative method to produce low-fat French fries

BACKGROUND

A large amount of evidence shows that excessive fat intake can increase the risk of obesity, type 2 diabetes, non-alcoholic fatty liver disease, and cardiovascular disease. The main purpose of this study was to use radio frequency (RF) technology to prepare low-fat French fries.

RESULTS

RF treatment for 10 min significantly decreased the force required to cut potatoes and inhibited the enzymatic browning of fresh-cut potatoes. Moreover, RF treatment increased the hardness, gumminess, and chewiness of French fries from 388.55 g, 85.67, and 33.27 to 776.93 g, 159.36, and 70.11, respectively. Furthermore, RF treatment for 10 min reduced the oil content of French fries by 28.0% compared to that of the control group. This result was related to the pre-gelatinized potato starch content after RF treatment. Pre-gelatinized starch forms a 'protective film', that prevents oil from entering the fries during frying.

CONCLUSION

Moderate RF treatment (10 min) reduced the oil content of French fries without making their texture significantly different from that of commercial French fries. These findings may provide a new perspective for the application of RF technology in the development of low-fat fried foods. © 2022 Society of Chemical Industry.

Effect of Hempseed Cake (Cannabis sativa L.) Incorporation on the Physicochemical and Antioxidant Properties of Reconstructed Potato Chips

Hempseed (Cannabis sativa L.) cake is a by-product after cold-pressing of oil from the hempseed, which is rich in protein and fiber. This study investigated the effect of hempseed cake incorporation on the physicochemical and antioxidant properties of reconstructed potato chips. Varying levels of hempseed cake (0, 5%, 10%, 15%, and 20%) were added, and the results showed that the addition of hempseed cake at 20% level significantly increased the protein and total dietary fiber content from 2.74 ± 0.62 g/100 g to 9.66 ± 0.28 g/100 g and from 2.76 ± 0.31 g/100 g to 13.57 ± 0.42 g/100 g, respectively. In addition, a 20% reduction in lipid content was observed in the 20% hempseed cake addition group. Furthermore, lightness value (L*) was significantly reduced from 72.23 ± 1.22 to 46.40 ± 1.76, while the hardness was enhanced with a higher level of hempseed cake supplementation in the potato chips sample. Compared with the control (no hempseed cake), the supplement of 20% cake increased the total phenolic content from 0.19 ± 0.01 to 0.26 ± 0.01 mg GAE/g. The ABTS radical scavenging rate was also significantly enhanced with the increased levels of hemp cake. However, the peroxide value and TBARS results showed that the addition of hempseed cake accelerated the lipid oxidation in the sample, possibly due to the highly unsaturated fatty acid residues in the hempseed cake. The results suggested that more research is needed for the incorporation of hempseed cake in potato chips.

Performance of Olive-Pomace Oils in Discontinuous and Continuous Frying. Comparative Behavior with Sunflower Oils and High-Oleic Sunflower Oils

Frying performance of olive-pomace oils (OPOs) as compared to sunflower oils (SOs) and high-oleic sunflower oils (HOSOs) was studied in discontinuous frying (DF) and continuous frying (CF) for the first time. DF is used in household, restaurants and frying outlets, while CF is used in the food industry. Oil alteration during frying was determined by measurements of polar compounds (PC) and polymers. Fried potatoes were analyzed for oil absorption and alteration, color, and evaluated in an acceptability test. Results for DF showed that all SOs reached 25% PC at the 9th frying operation (FO), whereas HOSOs did between the 17–18th FO and variable results were found for OPOs since initial levels of diacylglycerols were different. Rates of formation of PC or polymers were the lowest for OPOs, thus showing the best performance in DF. Specifically for PC, relative rates of formation were 1.00–1.11, 2.46–2.71 and 1.37–1.41 for OPOs, SOs and HOSOs respectively. In CF, OPOs and HOSOs behaved similarly and better than SOs, although none reached 25% PC after 40 FO. The good performance of OPOs can be attributed to the high monounsaturated-to-polyunsaturated ratio, in common with HOSOs, and the additional positive effect of minor compounds, especially β-sitosterol and squalene.

Effects of Methyl Cellulose and Soybean Protein Isolate Coating on Amount of Oil and Chemical Hazards in Chinese Fried Dough Cake

ABSTRACT

Fat-related diseases and chemical hazards produced during the frying process pose a major threat to human health. Coatings have been used as a practical method to reduce the amount of oil and chemical hazards associated with fried foods. Methyl cellulose (MC) and soy protein isolate were used as coating materials to pretreat Chinese fried dough cake (CFDC) before frying. The 1.5% MC concentration was the best choice for coating to simultaneously lower oil and chemical hazards in CFDC. The CFDC prepared using 1.5% MC had 11.3% oil, 73.70 μg/kg acrylamide, 0.15 mg KOH/100 kg acid, 8.54 mmol/kg peroxide, p-anisidine value of 6.36, 0.36 μg/g malondialdehyde, 0.13 μg/g 4-hydroxy-2-(E)-hexenal (HHE), 0.51 μg/g 4-hydroxy-2-(E)-nonenal (HNE), and 4,272 μg/kg glycidyl ester. In contrast, the uncoated CFDC had 19.2% oil, 117.55 μg/kg acrylamide, 0.25 mg KOH/100 kg acid, 14.40 mmol/kg peroxide, p-anisidine value of 9.76, 0.63 μg/g malondialdehyde, 0.23 μg/g HHE, 0.86 μg/g HNE, and 5,758 μg/kg glycidyl ester. MC and soy protein isolate enhanced the oil barrier of the coating film, which effectively reduced the heat transfer coefficients, oil transfer, oil oxidation, and chemical hazards in the CFDC. Our work on this edible coating contributes to methods for control of oil and chemical hazards in fried foods.

HIGHLIGHTS

Effect of oil surface activity on oil absorption behavior of potato strips during frying process

Oil absorption behavior of fried foods is affected by oil property during frying process. The present study investigated the effect of oil viscosity and surface activity on the oil uptake of fried potato strips with frying temperature. Results showed that oil content of palm oil (PO) and soybean oil (SBO) in fried strips increased with the frying temperature between 140 °C and 180 °C, while deceased at 200 °C. Oil distribution determined by LF-NMR and CLSM confirmed the changes of oil content of fried potato strips. Interfacial tension and surfactant content (monoglycerides, diglycerides, total polar compounds) of PO and SBO increased with frying temperature and affected the oil absorption of fried strips. Frying temperature and oil type showed no effect on surface tension. Besides, the higher level of viscosity, interfacial tension and surfactants of SBO than those of PO facilitated the more SO and TO of fried potato strips.

Characteristics of French Fries and Potato Chips in Aspect of Acrylamide Content—Methods of Reducing the Toxic Compound Content in Ready Potato Snacks

The reduction of toxic acrylamide content in potato snacks, i.e., French fries and potato chips, is necessary due to the adverse effects of this compound on the human body. Therefore, in the presented review paper, a detailed characterization of French fries and chips in terms of AA content and their organoleptic quality is included. Detailed information was also collected on the raw material and technological factors that affect the formation of acrylamide content, including methods and techniques affecting the reduction of the amount of this compound in potato snacks. The obligation to control the level of acrylamide in various food products (including fried potato snacks with a higher content of this compound), introduced in 2018, has mobilized manufacturers to seek solutions, while scientists conduct further intensive research on the possibility of reducing the level of AA or even eliminating its presence from products. Therefore, it is necessary to conduct such activities, especially, because potato French fries and potato chips are willingly consumed by younger and younger consumers.

Characterization of Non-volatile Oxidation Products Formed from Triolein in a Model Study at Frying Temperature

Frying allows cooking food while promoting their organoleptic properties, imparting crunchiness and flavor. The drawback is the oxidation of triacylglycerides (TAGs), leading to the formation of primary oxidized TAGs. Although they have been associated with chronic and degenerative diseases, they are precursors of pleasant flavors in fried foods. Nevertheless, there is a lack of knowledge about the oxidation species present in foods and their involvement in positive/negative health effects. In this work, high-resolution (HR) C₃₀ reversed-phase (RP)-liquid chromatography (LC)-tandem HR mass spectrometry (MS/MS) was used to identify primary oxidation TAGs resulting from heating triolein (160 °C, 5 min). This allows simulating the initial heating process of frying oils usually used to prepare fried foods, such as chips, crisps, and snacks. Beyond hydroxy, dihydroxy, hydroperoxy, and hydroxy-hydroperoxy derivatives, already reported in phospholipids oxidized by Fenton reaction, new compounds were identified, such as dihydroxy-hydroperoxy-triolein derivatives and positional isomers (9/10- and 9/12-dihydroxy-triolein derivatives). These compounds should be considered when proposing flavor formation pathways and/or mitigating lipid-derived reactive oxygen species occurring during food frying.

Recent advances in physical fields-based frying techniques for enhanced efficiency and quality attributes

Frying is one of the most common units in food processing and catering worldwide, which involves simultaneous physicochemical and structural changes. However, the problems of traditional frying technology, such as low thermal utilization and poor processing efficiency, have been gradually exposed to industrial production. In this paper, strategies of applying physical fields, such as pressure field, electromagnetic field, and acoustic field in frying technology separately or synergistically with improved efficiency and quality attributes are reviewed. The role of physical fields in the frying process was discussed with modifications in heat and mass transfer and porous structures. The effects of physical fields and their processing parameters on moisture loss kinetics, oil uptake, texture, color, and nutrients retention of fried food are introduced, respectively. Recent advances in multi-physical field-based frying techniques were recommended with synergistic benefits. Furthermore, the trends and challenges that could further develop the multi-physical field-based frying techniques are proposed, showing further commercial prospects for the purpose. The application of physical fields has brought new inspiration to the exploitation of efficient and high-qualified frying technologies, while higher technical levels and economic costs need to be taken into consideration. HighlightsThe role of physical fields in pretreatments and frying process were reviewed.The mechanism of physics fields on frying efficiency and quality was summarized.The physicochemical and microstructure changes by physics fields were discussed.The synergy of physical fields in frying technology were outlined.The trends for further multi-physical field-based frying techniques were proposed.

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

Deep-fried foods (e.g., French fries, potato/veggie crisps) are popular among consumers. Recently, there has been an increased interest in the application of Pulsed Electric Fields (PEF) technology as a pretreatment of plant-based foods prior to deep-frying to improve quality (e.g., lower browning tendency and oil uptake) and reduce production costs (e.g., better water and energy efficiencies). However, the influence of a PEF pretreatment on the frying process and related chemical reactions for food materials is still not fully understood. PEF treatment of plant tissue causes structural modifications, which are likely to influence heat, mass and momentum transfers, as well as altering the rate of chemical reactions, during the frying process. Detailed insights into the frying process in terms of heat, mass (water and oil) and momentum transfers are outlined, in conjunction with the development of Maillard reaction and starch gelatinisation during frying. These changes occur during frying and consequently will impact on oil uptake, moisture content, colour, texture and the amount of contaminants in the fried foods, as well as the fried oil, and hence, the effects of PEF pretreatment on these quality properties of a variety of fried plant-based foods are summarised. Different mathematical models to potentially describe the influence of PEF on the frying process of plant-based foods and to predict the quality parameters of fried foods produced from PEF-treated plant materials are addressed.