Modified Chinese quince oligomeric proanthocyanidin protects deep-frying oil quality by inhibiting oxidation

Chinese quince (Chaenomeles sinensis) fruit is an underutilized resource, rich in proanthocyanidins with antioxidant ability but poor lipid solubility. In this study, a novel modified oligomeric proanthocyanidin (MOPA) was prepared, which exhibited favorable lipid solubility (354.52 mg/100 g). It showed higher radical scavenging abilities than commercial antioxidant-BHA (butylated hydroxyanisole), both at 0.4-0.5 mg/mL. The addition of MOPA (0.04 %wt.) significantly increased the oxidative stability index of the soybean oil from 5.52 to 8.03 h, which was slightly lower than that of BHA (8.35 h). Analysis of the physicochemical properties and composition of oil during deep-frying showed that MOPA demonstrated significant antioxidant effects and effectively restricted the oil oxidation. This inhibition also delays the formation of heterocyclic amines (HAs) in fried food, thereby reducing the migration of HAs from food to deep-frying oil. Therefore, MOPA is a promising novel liposoluble antioxidant for protecting the quality of deep-frying oil.

Deep-frying palm olein oil-fried street falafel induces testicular toxicity in rats

Falafel is the most common Egyptian street food, and deep-frying palm oil is a commonly used for frying it. The main objective of this research was to evaluate the effect of deep-frying palm olein oil-fried street falafel on testes of Wistar rats. Twenty-one adult male Wistar rats were randomly divided into three equal groups and given treatment as follows: control group received only distilled water, fresh palm olein oil (FPO) group received FPO (1 ml/100 g BW/day) and deep-frying palm olein oil (DPO) group received DPO (1 ml/100 g BW/day) orally for 28 days. Serum level of testosterone, testicular tissue oxidative status, and sperm characteristics were determined. Testicular specimens were processed for histopathological examination. The results revealed that DPO group showed a significant (p<0.01) decrease in serum testosterone with significant (p<0.01) reduction of testicular glutathione, superoxide dismutase, and glutathione peroxidase, whereas testicular malondialdehyde was markedly (p<0.001) raised. There were significant decrease in epididymal sperm count (p<0.01), sperm progress motility (p<0.001), and increase abnormal sperm rate (p<0.001) in DPO group. Testicular histology in DPO group showed structural abnormalities which are compatible with lipid peroxidation and antioxidant deficiency. In Conclusion, deep-frying palm olein oil that used for the frying falafel induces testicular abnormalities in rats.

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.

Formation of AGEs in Penaeus vannamei fried with high oleic acid sunflower oil

Here, we investigated the effects of frying process on the formation of advanced glycation end products (AGEs) in shrimps using Penaeus vannamei as the raw material. The results showed that the oil, malondialdehyde, fluorescent AGEs, carboxymethyl lysine (CML), methylglyoxal hydroimidazolone (MG-H1) and the outer layer carboxyethyl lysine (CEL) content was higher in the fried shrimps than that in the raw unfried shrimps. The outer layer CML, CEL and inner CEL, MG-H1 values all reached the maximum after the first batch of frying (22.43 mg/kg, 304.24 mg/kg, 83.76 mg/kg, and 169.42 mg/kg respectively). However, fluorescent AGEs and MG-H1 of the outer layer reached the maximum after the fifth and fourth batches of frying (1230.0 AU/g and 341.63 mg/kg). Malondialdehyde, fluorescent AGEs, CML, MG-H1, and CEL concentration in the fried shrimps firstly increased and then decreased to stabilization with more frying batches, with higher content in the outer layer of fried shrimps.

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.

Effect of lyophilized chive (Allium wakegi Araki) supplementation to the frying batter mixture on quality attributes of fried chicken breast and tenderloin

Batter mixtures for frying chicken breasts and tenderloins were supplemented with different amounts (0, 3, 5, and 7%) of lyophilized chives (Allium wakegi Araki). The viscosity of the batter mixture, crispness of the fried batter, fat and ash contents, caloric value, coating pickup, and frying yield were directly proportional, whereas the lightness, redness, yellowness, and pH were inversely proportional, to the amount of lyophilized chives in the batter. Principal component analysis revealed that the aromatic profiles varied between the 0%, 3%, and 5% lyophilized chive-supplemented groups in both the breast and tenderloin samples. However, the aromatic profiles of the 7% and 5% lyophilized chive-supplemented samples were similar. The taste profile of the 7% lyophilized chive-supplemented sample was different from those of the 0%, 3%, or 5% lyophilized chive-supplemented samples. The sensory characteristics of the 5% lyophilized chive-supplemented breast samples and 3% or 5% lyophilized chive-supplemented tenderloin samples received the best scores by sensory panelists.

Potential of using basa catfish oil as a promising alternative deep-frying medium: A thermo-oxidative stability study

Basa catfish is a good source for fish oil extraction, which was believed to have good thermo-oxidative stability because of its similar fatty acid composition to that of palm olein (PO). The thermo-oxidative stability of PO, basa catfish oil (FO), and palm olein-basa fish oil blend (PO-FO; ratio 1:1) was evaluated after 75 frying cycles. No significant difference was observed in p-anisidine value, TOTOX value, conjugated trienes, monomeric oxidized triacylglycerols, and free fatty acids concentration after frying. Moreover, compared to PO, FO exhibited lighter color, lower acid value, conjugated dienes, polymerized triacylglycerol, and total polar content. The PO-FO blend also demonstrated a more favorable frying stability compared to the other two frying systems. These findings indicated that FO could be proposed as a promising alternative to common PO, and its blending with other vegetable oils at an appropriate ratio might improve the overall oil frying quality for future industrial applications.

Change of benzo(a)pyrene during frying and its groove binding to calf thymus DNA

Benzo[a]pyrene (BaP), a prototype of polycyclic aromatic hydrocarbons (PAHs) with potential mutagenicity, toxicity and carcinogenicity, is ubiquitous in deep-fried foods. Herein, the changes in eight specific PAHs (PAH8) concentration in sunflower oil during frying were investigated by gas chromatography-triple quadrupole-mass spectrometry (GC-QqQ-MS). PAH8 concentrations in sunflower oil were 23.92-27.82 μg kg^-1 and increased with increasing frying time. The detected BaP levels were 3.64-4.00 μg kg^-1, exceeding the upper limit (2 μg kg^-1) set by European Union (EU), though below the limiting value (10 μg kg^-1) in China. The interaction between BaP and calf thymus DNA (ctDNA) was explored through various spectroscopic methods and molecular docking. Melting studies, denaturation experiments, ionic strength effects and viscosity measurements indicated that BaP interacted with ctDNA primarily via groove binding as evidenced by circular dichroism analysis and molecular docking. Further gel electrophoresis assays suggested that DNA was damaged at high levels of BaP.

Fried pork loin batter quality with the addition of various dietary fibers

The effect of the addition of dietary fiber extracted from wheat, bamboo, and oat on the quality of fried pork loin batter was investigated. Quality evaluation included proximate composition, pH, color, viscosity, coating and frying yield, electronic nose, and sensory evaluation. Regarding proximate composition of fried batter and fried pork loin, the water content of the dietary fiber treatments was significantly higher than that of the control (p < 0.05), whereas fat content was significantly lower than that of the control (p < 0.05). The lightness of non-fried batter with dietary fiber treatments was significantly higher than that of the control (p < 0.05), whereas the yellowness was significantly lower than that of the control (p < 0.05). The lightness, redness, and yellowness of fried pork loin with dietary fiber treatment were significantly lower than those of the control (p < 0.05). The viscosity and coating and frying yield of dietary fiber treatments were significantly higher than those of the control (p < 0.05). The volatile compounds of dietary fiber treatments were decreased “tallowy” flavor and increased “buttery” and “milky” flavor. The principal components of bamboo and oat fiber treatments were clearly distinguishable from those of the control; however, similar principal components as those of the control were obtained with wheat fiber treatment. Regarding sensory evaluation, the color, texture, and overall acceptability of wheat and oat fiber treatments were significantly higher than those of the control (p < 0.05), and the flavor of the wheat fiber treatment was significantly higher than that of the control (p < 0.05). These results show that wheat and oat fibers are suitable for fried pork loin batter and improve its quality.

Evaluation of glycerol core aldehydes formation in edible oils under restaurant deep frying

Glycerol core aldehydes (GCAs) are potentially toxic lipid oxidation products characterized by aldehydic acids bonded to glycerol via acyl groups. This study investigated the profile and change of GCAs in rapeseed oil (RO), high-oleic sunflower oil (HOSO) and cottonseed oil (CO) after frying chicken nuggets (CNs), fish nuggets (FNs) and French fries (FFs) for 60 h in real restaurant frying systems. Three GCAs (8-oxo, 9-oxo, and 10-oxo-8) were identified, with the GCAs (9-oxo) accounting for the highest value (60%), followed by GCAs (10-oxo-8) and GCAs (8-oxo). The total GCAs increased from 1.12 to 2.02 mg/g with frying time from 0 to 60 h in RO used for frying FNs. The FN frying systems produced the largest amount of GCAs, whereas the FF frying systems produced the least. RO contained more GCAs than CO and HOSO owing to its higher unsaturated fatty acid content (91.81%). Furthermore, the GCAs showed a high correlation with polymerized and oxidized products, indicating that the formation of GCAs were related to the oxidative stability of oils. These results may provide insight into the formation of GCAs and their control during frying.

Fried potatoes: Impact of prolonged frying in monounsaturated oils

Fresh potatoes were intermittently deep-fried up to recommended limits (175°C, 8h/day, 28h) in extra-virgin olive oil (EVOO), peanut oil (PO) and canola oil (CO), and compared for diverse chemical components and sensorial attributes, aiming to quantify the impact of prolonged frying on potatoes nutrients, and the potential alterations resulting from the use of different monounsaturated-rich oils. Independently of oil type, its degradation promotes time-dependent losses of important potato nutrients, as vitamin C. Regarding the monounsaturated-rich oils tested, potatoes fried in CO had more equilibrated fatty acid profiles, but higher amounts of aldehydes derived from PUFA oxidation, while in EVOO were enriched with phenolic compounds. Acrylamide amounts were not affected by oil type or frying hours. Sensory degradation was gradually perceived by the panellists, except in PO. Prolonged frying should not be studied only on the basis of oil degradation because, even if within regulated limits, it induces loss of important food compounds.

Indoor air quality in a restaurant kitchen using margarine for deep-frying

Indoor air quality has a great impact on human health. Cooking, in particular frying, is one of the most important sources of indoor air pollution. Indoor air CO, CO2, particulate matter (PM), and volatile organic compound (VOC) concentrations, including aldehydes, were measured in the kitchen of a small establishment where a special deep-frying margarine was used. The objective was to assess occupational exposure concentrations for cooks of such restaurants. While individual VOC and PM2.5 concentrations were measured before, during, and after frying events using active sampling, TVOC, PM10, CO, CO2, temperature, and relative humidity were continuously monitored through the whole period. VOC and aldehyde concentrations did not increase to considerable levels with deep-frying compared to the background and public indoor environment levels, whereas PM10 increased significantly (1.85 to 6.6 folds). The average PM2.5 concentration of the whole period ranged between 76 and 249 μg/m(3). Hence, considerable PM exposures could occur during deep-frying with the special margarine, which might be sufficiently high to cause health effects on cooks considering their chronic occupational exposures.

Heat and mass transfer in deep-frying of pumpkin, sweet potato and taro

Heat and mass transfer parameters, effective thermal diffusivity, heat transfer coefficient, effective moisture diffusivity and moisture transfer coefficient-for pumpkin (Cucurbita pepo), sweet potato (Ipomoea batatas) and taro (Colocasia esculenta) under deep-frying conditions were determined by fitting experimental data on transient values of temperature and moisture content to the solution of the standard diffusion equation in cylindrical coordinates as modified by Dincer (Heat Mass Transfer 32:109-113, 1996). A case of Biot number in the range of 0< B i <100 was considered in this study. Remarkably good agreement was found between estimated and calculated values as the root mean square error between the measured and calculated temperature and moisture content values were only 5.0% and 1.3%, respectively. The model can be easily and effectively used to determine effective diffusion coefficients as well as transfer coefficients for heat and mass transfer. The oil uptake values for the above vegetables were lower than the values reported for other deep fried products.