The effects of different frying oils on the formation of heterocyclic aromatic amines in meatballs and the changes in fatty acid compositions of meatballs and frying oils.

BACKGROUND: The effects of different frying oils (sunflower, hazelnut, canola, commercially mixed, corn, riviera olive, and natural extra virgin olive) on the formation of heterocyclic aromatic amines (HCAs) in meatballs, and the changes in fatty acid composition of meatballs and frying oils before and after deep-fat frying, were determined. RESULTS: Frying oils had a very significant effect (P < 0.01) on fatty acid composition and the total HCA content of meatballs. It was determined, in meat, intermuscular fat, meatballs, and all of the different frying oils, that the most common saturated fatty acids (SFAs) were palmitic acid and stearic acid, the most common monounsaturated fatty acid (MUFA) was oleic acid, and the most common polyunsaturated fatty acid (PUFA) was linoleic acid. Only 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) was detected in deep-fat fried meatballs, whereas other HCAs (2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ), 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-9H-pyrido[2,3-b]indole (AαC) and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC)) could not be detected. The total amount of HCAs in the meatballs ranged between 30.43 and 43.71 ng g-1 . CONCLUSION: The results of the present study showed that MeIQx could be formed in deep-fat fried meatballs with different frying oils. The lowest MeIQx content was found in meatballs fried in hazelnut oil and the highest MeIQx content was found in meatballs fried in commercially mixed oil. © 2018 Society of Chemical Industry.

Frying oils with high natural or added antioxidants content, which protect against postprandial oxidative stress, also protect against DNA oxidation damage.

PURPOSE: Using sunflower oil as frying oil increases postprandial oxidative stress, which is considered the main endogenous source of DNA oxidative damage. We aimed to test whether the protective effect of virgin olive oil and oil models with added antioxidants against postprandial oxidative stress may also protect against DNA oxidative damage. METHODS: Twenty obese people received four breakfasts following a randomized crossover design consisting of different oils [virgin olive oil (VOO), sunflower oil (SFO), and a mixed seed oil (SFO/canola oil) with added dimethylpolysiloxane (SOX) or natural antioxidants from olives (SOP)], which were subjected to 20 heating cycles. RESULTS: We observed the postprandial increase in the mRNA levels of p53, OGG1, POLB, and GADD45b after the intake of the breakfast prepared with SFO and SOX, and an increase in the expression of MDM2, APEX1, and XPC after the intake of the breakfast prepared with SFO, whereas no significant changes at the postprandial state were observed after the intake of the other breakfasts (all p values <0.05). We observed lower 8-OHdG postprandial levels after the intake of the breakfast prepared with VOO and SOP than after the intake of the breakfast prepared with SFO and SOX (all p values <0.05). CONCLUSIONS: Our results support the beneficial effect on DNA oxidation damage of virgin olive oil and the oil models with added antioxidants, as compared to the detrimental use of sunflower oil, which induces p53-dependent DNA repair pathway activation.

Effect of pre-treatments and frying conditions on the formation of starch-lipid complex in potato starch chips during deep-frying process.

This study examined the influence of various pretreatment methods, frying durations, and temperatures, as well as the type of frying oil, on the formation and structure of starch-lipid complexes in fried potato chips. Potato starch was processed into dough, sliced, and subjected to deep frying following various pretreatments. Structural analysis showed that steaming as a pretreatment facilitated the generation of V-type starch-lipid complexes, whereas resistant starch type III (RS3) materialized in the desiccated samples instead of the anticipated complexes. The rate of starch-lipid complex formation initially surged but subsequently declined as treatment time increased. A reduction in treatment temperature from 190 °C to 170 °C was conducive to complex formation. Moreover, the maximum relative crystallinity (19.74 %) and ΔH value (7.76 J/g) were recorded for potato starch slices pretreated by steaming and frying in palm oil. Rapeseed oil, which is rich in unsaturated fatty acids (89.98 %), inhibits complex formation. The study concludes that pretreatment methods exert a substantial effect on the formation of starch-lipid complexes and that extended frying duration and elevated temperature may reduce this formation. Oils with longer-chain fatty acids and a lower degree of unsaturation were favorable for complex formation.

Machine learning-based predictive analysis of total polar compounds (TPC) content in frying oils: A comprehensive electrochemical study of 6 types of frying oils with various frying timepoints.

Standard approaches to determining the total polar compounds (TPC) content in frying oils such as the chromatographic techniques are slow, bulky, and expensive. This paper presents the electrochemical analysis of 6 types of frying oils inclusive of 52 frying timepoints, without sample preparation. This is achieved via impedance spectroscopy to capture sample-specific electrical polarization states. To the best of our knowledge, this is a first-of-its-kind comprehensive study of various types of frying oils, with progressively increasing frying timepoints for each type. The principal component analysis distinguishes the frying timepoints well for all oil types. TPC prediction follows, involving supervised machine learning with sample-wise leave-one-out implementation. The R2 values and mean absolute errors across the test samples measure 0.93-0.97 and 0.43-1.19 respectively. This work serves as a reference for electrochemical analysis of frying oils, with the potential for portable TPC predictors for rapid accurate screening of frying oils.

Effects of Thermally-Oxidized Frying Oils (Corn Oil and Lard) on Gut Microbiota in Hamsters.

Repeated reuse of frying oil raises health concerns due to the accumulation of oxidative products after each frying cycle. Gut microbiota is integral in lipid metabolism and immune regulation. The present study was designed to investigate the effects of thermally-oxidized corn oil and lard on gut microbiota in relation to atherosclerosis, inflammatory cytokines, and plasma lipids. Male Golden Syrian hamsters were randomly divided into four groups and fed one of four diets containing fresh corn oil (CF), oxidized corn oil (CO), fresh lard (LF), and oxidized lard (LO), for six weeks. CO and LO were prepared by deep-frying potatoes in corn oil or lard for seven days. Results indicated that oxidized oil and lard caused the loss of species diversity and richness of gut microbiota. Feeding CO and LO also reduced the body and adipose tissue weights, associated with genus Acetatifactor and Allobaculum. Plasma triacylglycerols significantly increased by 51% in the CO and 35% in the LO group compared with that in their CF and LF counterparts, respectively. CO could also affect the abundance of specific bacteria genera: Bacteroides, Barnesiella, Acetatifactor, Allobaculum, Clostridium_IV, Clostridium_XIVa, Coprococcus, Lactococcus, Paraprevotella, Parasutterella, and Oscillibacter. In addition, CO and LO could adversely remodel gut composition and affect intestinal production of short-chain fatty acids, pro-inflammatory biomarkers (LPS and IL-6), anti-inflammatory biomarker IL-10, and atherosclerotic progression. It was concluded that frying oil could adversely modulate the gut microbiota and exacerbate the atherosclerosis at least in a hypercholesterolemia hamster model.

Evidence-Based Challenges to the Continued Recommendation and Use of Peroxidatively-Susceptible Polyunsaturated Fatty Acid-Rich Culinary Oils for High-Temperature Frying Practises: Experimental Revelations Focused on Toxic Aldehydic Lipid Oxidation Products.

In this manuscript, a series of research reports focused on dietary lipid oxidation products (LOPs), their toxicities and adverse health effects are critically reviewed in order to present a challenge to the mindset supporting, or strongly supporting, the notion that polyunsaturated fatty acid-laden frying oils are "safe" to use for high-temperature frying practises. The generation, physiological fates, and toxicities of less commonly known or documented LOPs, such as epoxy-fatty acids, are also considered. Primarily, an introduction to the sequential autocatalytic peroxidative degradation of unsaturated fatty acids (UFAs) occurring during frying episodes is described, as are the potential adverse health effects posed by the dietary consumption of aldehydic and other LOP toxins formed. In continuance, statistics on the dietary consumption of fried foods by humans are reviewed, with a special consideration of French fries. Subsequently, estimates of human dietary aldehyde intake are critically explored, which unfortunately are limited to acrolein and other lower homologues such as acetaldehyde and formaldehyde. However, a full update on estimates of quantities derived from fried food sources is provided here. Further items reviewed include the biochemical reactivities, metabolism and volatilities of aldehydic LOPs (the latter of which is of critical importance regarding the adverse health effects mediated by the inhalation of cooking/frying oil fumes); their toxicological actions, including sections focussed on governmental health authority tolerable daily intakes, delivery methods and routes employed for assessing such effects in animal model systems, along with problems encountered with the Cramer classification of such toxins. The mutagenicities, genotoxicities, and carcinogenic potential of aldehydes are then reviewed in some detail, and following this the physiological concentrations of aldehydes and their likely dietary sources are considered. Finally, conclusions from this study are drawn, with special reference to requirements for (1) the establishment of tolerable daily intake (TDI) values for a much wider range of aldehydic LOPs, and (2) the performance of future nutritional and epidemiological trials to explore associations between their dietary intake and the incidence and severity of non-communicable chronic diseases (NCDs).

Comparative 1H NMR-Based Chemometric Evaluations of the Time-Dependent Generation of Aldehydic Lipid Oxidation Products in Culinary Oils Exposed to Laboratory-Simulated Shallow Frying Episodes: Differential Patterns Observed for Omega-3 Fatty Acid-Containing Soybean Oils.

Soybean oil is the second most exported oil from the United States and South America, and is widely marketed as a cooking oil product containing numerous health benefits for human consumers. However, culinary oils with high polyunsaturated fatty acid (PUFA) contents, are known to produce high quantities of lipid oxidation products (LOPs), including toxic aldehydes upon exposure to high-temperature frying episodes. Previous studies have demonstrated causal links between aldehyde ingestion and inhalation with deleterious health perturbations, including mutagenic and carcinogenic effects, along with cardiovascular and teratogenic actions. In this study, aldehydic LOPs were detected and quantified in commercially available samples of soybean, avocado, corn and extra-virgin olive oil products before and after their exposure to laboratory-simulated laboratory frying episodes (LSSFEs) using high-resolution 1H nuclear magnetic resonance (NMR) analysis. Results acquired demonstrated that PUFA-rich soybean and corn oils gave rise to the highest concentrations of oil aldehydes from the thermo-oxidation of unsaturated fatty acids, whereas monounsaturated fatty acid (MUFA)-laden avocado and olive oils were much more resistant to this peroxidation process, as expected. Multivariate chemometrics analyses provided evidence that an orthogonal component pattern of aldehydic LOPs featuring low-molecular-mass n-alkanals such as propanal, and 4-oxo-alkanals, arises from thermo-oxidation of the ω-3 fatty acid (FA) linolenic acid (present in soybean oils at levels of ca. 7% (w/w)), was able to at least partially distinguish this oil from corresponding samples of thermally-stressed corn oil. Despite having a similar total PUFA level, corn oil has only a negligible ω-3 FA content, and therefore generated significantly lower levels of these two aldehyde classes. In view of the adverse health effects associated with dietary LOP ingestion, alternative methodologies for the incorporation of soybean oils within high-temperature frying practices are proposed.

Potential Adverse Public Health Effects Afforded by the Ingestion of Dietary Lipid Oxidation Product Toxins: Significance of Fried Food Sources.

Exposure of polyunsaturated fatty acid (PUFA)-rich culinary oils (COs) to high temperature frying practices generates high concentrations of cytotoxic and genotoxic lipid oxidation products (LOPs) via oxygen-fueled, recycling peroxidative bursts. These toxins, including aldehydes and epoxy-fatty acids, readily penetrate into fried foods and hence are available for human consumption; therefore, they may pose substantial health hazards. Although previous reports have claimed health benefits offered by the use of PUFA-laden COs for frying purposes, these may be erroneous in view of their failure to consider the negating adverse public health threats presented by food-transferable LOPs therein. When absorbed from the gastrointestinal (GI) system into the systemic circulation, such LOPs may significantly contribute to enhanced risks of chronic non-communicable diseases (NCDs), e.g. cancer, along with cardiovascular and neurological diseases. Herein, we provide a comprehensive rationale relating to the public health threats posed by the dietary ingestion of LOPs in fried foods. We begin with an introduction to sequential lipid peroxidation processes, describing the noxious effects of LOP toxins generated therefrom. We continue to discuss GI system interactions, the metabolism and biotransformation of primary lipid hydroperoxide LOPs and their secondary products, and the toxicological properties of these agents, prior to providing a narrative on chemically-reactive, secondary aldehydic LOPs available for human ingestion. In view of a range of previous studies focused on their deleterious health effects in animal and cellular model systems, some emphasis is placed on the physiological fate of the more prevalent and toxic α,ß-unsaturated aldehydes. We conclude with a description of targeted nutritional and interventional strategies, whilst highlighting the urgent and unmet clinical need for nutritional and epidemiological trials probing relationships between the incidence of NCDs, and the frequency and estimated quantities of dietary LOP intake.

Preliminary economic assessment of the use of waste frying oils for biodiesel production in Beirut, Lebanon.

In this study, a method for assessing the costs of biodiesel production from waste frying oils in Beirut, Lebanon, was investigated with the aim of developing an economic evaluation of this alternative. A hundred restaurant and hotel enterprises in Beirut were surveyed for promoting them in participating in the biodiesel supply chain, and for data collection on waste frying oils generation, disposal methods and frequency, and acquisition cost. Also, waste frying oils were collected and converted into biodiesel using a one-step base catalyzed transesterification process. Physicochemical characteristics of the produced biodiesel were conforming to international standards. Data produced from laboratory scale conversion of waste frying oils to biodiesel, as well as data collected from the only biodiesel plant in Lebanon was used to determine the production cost of biodiesel. Geographic Information System was used to propose a real-time vehicle routing model to establish the logistics costs associated with waste frying oils collection. Comparing scenarios of the configuration collection network of waste frying oils, and using medium-duty commercial vehicles for collection, a logistics cost of US$/L 0.08 was optimally reached. For the calculation of the total cost of biodiesel production, the minimum, average, and maximum values for the non-fixed cost variables were considered emerging 81 scenarios for possible biodiesel costs. These were compared with information on the commercialization of diesel in Lebanon for the years 2011 through 2017. Although competitive with petroleum diesel for years 2011 to 2014, the total biodiesel cost presented less tolerance to declining diesel prices in the recent years. Sensitivity analysis demonstrated that the acquisition cost of waste frying oils is the key factor affecting the overall cost of biodiesel production. The results of this study validate the economic feasibility of waste frying oils' biodiesel production in the studied urban area upon enforcement of low waste frying oils' acquisition costs, and can help spur food service enterprises to become suppliers of biodiesel production feedstock and support a healthy development of the biodiesel industry in Lebanon.

A sustainable use of low-cost raw substrates for biodiesel production by the oleaginous yeast Wickerhamomyces anomalus.

Over the past decade, the increasing demand of vegetable oils for biodiesel production has highlighted the need for alternative oil feedstocks that do not compete with food production. In this context, the combined use of agro-industrial wastes and oleaginous microorganisms could be a promising strategy for sustainable biodiesel production. The present investigation involves the performance of the oleaginous yeast Wickerhamomyces anomalus strain EC28 to produce lipids from different agro-industrial wastewaters (i.e., deproteinized cheese whey, olive mill wastewater, and wastewaters from confectionary industries) and waste frying oils (i.e., waste oil from frying fish, waste oil from frying potato and waste oil from frying meat). Results indicated that this strain can adequately grow on agro-industrial wastewater-based media and produce substantial amounts of lipids [up to 24%, wt/wt in deproteinized cheese whey-based medium and olive mill wastewater-based medium (75%, v/v in water)] of similar fatty acid composition to that of the most commonly used vegetable oils in the biodiesel industry. However, the addition of frying oils to the culture media resulted in a significant decrease in total lipid content, probably due to excess of available nitrogen released from meat, fish, and potato into the frying oil. The estimated properties of the resulting biodiesels, such as SV (190.69-203.13), IV (61.77-88.32), CN (53.45-59.32), and CFPP (-0.54 to 10.4), are reported, for the first time, for W. anomalus and correlate well with specified standards. In conclusion, W. anomalus strain EC28, for which there is very limited amount of available information, might be regarded as a promising candidate for biodiesel production and additional efforts for process improvement should be envisaged.

Comparative study of oxidative stress biomarkers in urine of cooks exposed to three types of cooking-related particles.

OBJECTIVES: To evaluate how exposure to deep-frying oils, repeated frying oil (RFO) and restaurant waste oil (RWO) affects emission of polycyclic aromatic hydrocarbons (PAHs) and oxidative stress in male restaurant workers. METHODS: The study participants included 236 male restaurant workers in 12 restaurants in Shenzhen. Airborne particulate PAHs were measured over 12h on each of two consecutive work days. Urinary 1-hydroxypyrene (1-OHP) measurements were used to indicate cooking oil fumes (COF) exposure, and urinary malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG) were adopted as oxidative stress markers. RESULTS: The production and emission rates of ultrafine particles (UFPs) and PM2.5 were higher in the exposed groups than in the control group. The concentrations of summed PAHs were in the order of RFO-frying group>RWO-frying group>deep-frying group>unexposed control group. Urinary 1-OHP was found to be a significant predictor of elevated urinary MDA and 8-OHdG concentrations (all, P<0.05). UFPs were a significant predictor of elevated urinary 8-OHdG for restaurant workers (P<0.05). The RFO- and RWO-frying groups had higher mean urinary concentrations of 1-OHP, MDA and 8-OHdG than the control group (P<0.05). RFO exposure was found to be a significant risk factor for elevated urinary 8-OHdG and RWO exposure was found to be a significant risk factor for elevated urinary MDA (both, P<0.001). CONCLUSIONS: Concentrations of urinary 1-OHP, MDA and 8-OHdG reflect occupational exposure to PAHs from COFs and oxidative stress in restaurants workers. Exposure to RFO may cause increased oxidative DNA damage, and exposure to RWO might cause increased lipid peroxidation.

Local Repeatedly-Used Deep Frying Oils Are Generally Safe

A review of the literature indicates that food scientists and health authorities in several countries, especially member countries of the European Union, are still very concerned about the potential health hazards of oxidized products and lipid polymers formed in repeatedly-used deep frying oils. During the frying process at temperatures of 170° – 200°C, steam formed from moisture in the food being fried help volatile products rise to the surface of the frying medium and into the kitchen atmosphere, imparting a mixture of fried-flavours and off-flavours. The non-volatile compounds formed, however, gradually build up in the oil as it is being repeatedly-used for food frying operations. These non-volatiles, primarily “polar compounds” (PC) and to a lesser extent lipid polymers, get absorbed into fried foods and eventually end up in our body system. Available local data suggests that deep-frying oil samples obtained from food hawkers and those produced under simulated deep-frying conditions in the laboratory, are generally safe as they contain PC within safe limits and rarely exceed the upper limit (UL) of 25%. This contrasts with the situation in some European countries where a very high proportion of frying oil samples collected from fast-food restaurants were reported to contain PC exceeding this UL. A p p r o p r i a t e l y, promotion of Hazard Analysis and Critical Control Points (HACCP) certification and gazetting of food regulations to limit the PC content in frying oils have been introduced in these countries to protect the health of consumers. Meanwhile, simple gadgets/test kits are available commercially to monitor the quality of the frying oil. This would greatly assist kitchen supervisors at restaurants and franchised friedfood outlets to know when best to change a batch of frying oil before the ULs of frying oil quality are breached.

The effects of repeatedly heated frying oil and high cholesterol diet on the bone in ovariectomised rats

The use of repeatedly heated frying oils and intake of high cholesterol diet have been linked to bone damage. The aim of this study is to determine the combined effects of taking repeatedly heated frying oils (palm or soy oil) and high cholesterol diet on the dynamic histomorphometric parameters of bone. Ovariectomised rats were used as animal model of post-menopausal osteoporosis. After six months of treatment, Double-labeled Surface (dLS/BS), Mineralising surface (MS/BS) and Bone Formation Rate (BFR/BS) of ovariectomised rats (OvxC) were significantly reduced compared to the normal control group. Additions of fresh or once-heated palm or soy oil into high cholesterol diet seem to have improved the dynamic parameters towards the normal control values. However, when these oils were repeatedly heated, the protective effects were lost and the dynamic parameters except MS/BS dropped back towards the ovariectomised-control values.