ANTIRADICAL PERFORMANCE AND PHYSICOCHEMICAL CHARACTERISTICS OF VEGETABLE OILS UPON FRYING OF FRENCH FRIES: A PRELIMINARY COMPARATIVE STUDY

Palm Oil (Elaeis guineensis): A Journey through Sustainability, Processing, and Utilization

Palm oil, derived from Elaeis guineensis, is a critical component of the global edible oil and industrial fat market. This review provides a comprehensive overview of the sustainability of the palm oil chain, focusing on industrial applications, environmental implications, and economic sustainability. The processing of palm oil, from fruit pulp to refined oil, is detailed, highlighting the importance of refining in maintaining quality and extending application ranges. While palm oil offers health benefits because of its rich fatty acid composition and antioxidant properties, its production poses significant environmental challenges. This review underscores ongoing efforts to balance technological and culinary demands with environmental stewardship and sustainable economic growth. Emerging trends, including interspecific hybrids such as E. guineensis and E. oleifera, are discussed for their potential to increase sustainability and productivity.

Study of the behavior and properties of frying oil on repetitive deep frying

The current work focused on the effect of repetitive frying on the physicochemical characteristics of palm oil (PO)and sesame oil (SO) during the preparation of french fries by deep fat frying. A total of 16 frying cycles were carried out and the effect on various parameters was evaluated. The repetitive frying caused higher damage to sesame oil as compared with PO as observed from changes in FFA and PV which increased to 0.63 ± 0.12, 1.31 ± 0.16%, and 2.71 ± 0.02, 7.21 ± 0.01 meq/kg from an initial value of 0.28 ± 0.00, 0.93 ± 0.16% and 0.19 ± 0.00, 0.71 ± 0.00 meq/kg for PO, SO respectively. The fatty acid composition of SO showed significant change with a decrease in linoleic acid and oleic acid content from 42.7 ± 0.01 to 28.1 ± 0.03 and 36.2 ± 0.01 to 25.1 ± 0.01 after 16 frying cycles respectively. The oleic acid content of PO was less affected it decreased from an initial value of 42.4 ± 0.01 to 38.9 ± 0.01 after 16 cycles. The fatty acid composition of PO made it more stable to the repetitive frying process. The physical properties like density refractive index and viscosity of SO were badly affected by repetitive frying. The french fries fried in PO score higher overall acceptability in the sensory examination.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05774-4.

Novel Water-Oil Mixed Frying: Fried Oil Quality and the Formation of Heterocyclic Amines and Trans Fatty Acids in Fried Duck

The present study was conducted to explore the impact of novel water–oil mixed frying and traditional oil frying methods on the soybean oil quality and formation of trans fatty acids (TFAs) and heterocyclic amines (HCAs) in fried duck breast and skin during 60 frying cycles. The acid value of the soybean oil was 2.10 mg/g using the traditional oil frying and 1.08 mg/g using water–oil mixed frying at the 60th frying cycle. The peroxide value of the water–oil mixed fried soybean oil was significantly lower than that of the traditional frying method. Water–oil mixed frying delayed the formation of TFAs in the soybean oil. The traditionally oil fried skin showed increased TFAs (9tC16:1) content from 0.17 to 0.22 mg/g (29.4% increase), while those of the water–oil mixed fried samples increased from 0.16 to 0.20 mg/g (25.00% increase) compared to control. Harman, Norharman and AαC were detected in all the fried samples and PhIP was observed after the 20th frying cycle, while MeAαC was formed only at the 60th frying cycle in traditional fried duck breast. Therefore, it is concluded that the water–oil mixed frying method is more suitable to improve the quality and safety of fried duck skin and breast meat.

Formulation of Stable Frying Oil for Food Industry by Using Various Edible Oils and Antioxidants

Background:

Frying oils are important nutrition due to their significant changes during the frying process. These changes can cause serious health problems in consumers.

Methods:

The aims of this 3-stage study were to investigate chemical changes of Total Polar Compounds (TPC), Peroxide Value (PV), Free Fatty Acid (FFA), Anisidine Value (AV) and TOTOX Value (TV) during heating of four improved frying oil formulations including super palm olein, sunflower, rapeseed and corn oil and to assess their frying quality, blends and subsequent changes using various antioxidant compounds, including ter-butyl Hydroquinone (TBHQ) and its mixture with Ascorbyl Palmitate (ASCP).

Results:

Results showed that the best formulation at the end of frying time was FO5 including 1:1 super palm olein and corn oil containing 120 ppm of TBHQ, 120 ppm of ASCP and 0.01% of Citric Acid (CA). This formulation showed the minimum TPC, PV, TV and FFA, compared to those other formulations.

Conclusion:

Furthermore, AP was demonstrated to include synergistic effects on TBHQ in preventing thermal deterioration of the frying oils.

Postmarketing surveillance of the oxidative stability for cooking oils, frying oils, and vanaspati supplied in the retail market

In this study, postmarketing surveillance (PMS) was conducted in terms of the parameters which are reliable indicators of the oxidative stability of cooking oils, frying oils, and vanaspati samples. The analyzed parameters were fatty acid composition, peroxide value (PV), free fatty acids (FFA), p-anisidine value (p-AV), induction period at 110°C (IP110) determined by Rancimat test, and TOTOX value. For this purpose, different samples from four highly popular brands of mentioned products were randomly collected from Iran's market during 2016-2018. All monitored products had trans fatty acid <1.0%. In the case of FFA and IP110, the ranges of 0.03-0.08 (%) and 9.3-17.2 hr were obtained, respectively, being mostly in conformity with the National Standard of Iran (FFA < 0.1% and IP110  > 15 hr). The ranges of PV of cooking oils, frying oils, and vanaspati samples were 1.2-2.7, 0.93-2, and 0.84-1.6 meq/kg, respectively. Our results revealed that p-AV of frying oils and cooking oils was mostly outside of legal limits of Iran (p-AV > 6) with the ranges of 4.2-12.5 and 4.3-12.3, respectively. In terms of TOTOX value, monitored products had a range from 5.2 to 13.0 (mostly <10) being nearly acceptable.

Impact of Purslane (Portulaca oleracea L.) Leaves Extract to Enhance the Anti-oxidant Potential of Edible Oils during Heating

The present work deals/ reveals with the effect of purslane leaves extract on the stability of soybean oil during heating and the acceptability of oil after preparation of poori (an Indian fried bread) by frying and its sensory evaluation. The ethanolic purslane leaves extract was blended with soybean oil at three different concentrations such as, 500, 1000 and 1500 ppm (T1, T2 and T3) and compared with control. The sample added with 100 ppm TBHQ was used as a positive control. Assessment of antioxidant activity of the ethanolic extract of purslane leaves was carried out by the estimation of total phenolic content, loss of β-carotene and antioxidant activity. The heating (173±2°C for 24 h; 8 h heating cycles per day) performance of soybean oil incorporated with purslane leaves extract was evaluated in terms of peroxide value, free fatty acid, total polar material and fatty acid composition. The thermal stability of the oils was evaluated using differential scanning calorimeter. The poori was prepared to check the acceptability of the oil. Results suggest that leaves extract of purslane (1500 ppm) may be used for obtaining reasonable thermal stability of soybean oil with acceptable sensory characteristics of the product. Although TBHQ showed almost similar thermal stability with leaves extract of purslane (1500 ppm), natural anti-oxidant is more preferred over synthetic anti-oxidant.

The influence of high-temperature heating on composition and thermo-oxidative stability of the oil extracted from Arabica coffee beans

The aim of the present study was to establish the influence of high-temperature heating on the composition and thermal behavior of coffee oils obtained from Arabica green and roasted coffee beans, respectively. Morphological studies performed using scanning electron microscopy revealed the oil bodies uniformly distributed within the cells in both types of coffee beans analyzed. The obtained oils have a fatty acid composition rich in linoleic acid, palmitic acid, oleic acid, stearic acid, arachidic acid and linolenic acid. The total content of saturated fatty acids of investigated oils was 49.38 and 46.55%, the others being unsaturated fatty acids. The thermal behavior and thermo-oxidative stability of coffee oils extracted from green coffee beans and roasted coffee beans, the coffee oil high-temperature heated up to 200 °C, were investigated using simultaneous thermal analysis TG/DTG/DTA, in an oxidizing atmosphere. The data obtained for the analyzed samples depend mainly on the nature and compositions of fatty acids, and to a lesser extent on the roasting process of the coffee beans and the high-temperature heating process of the extracted oil. The chromatographic and TG/DTG/DTA data suggest that Arabica coffee oil has great potential for use in technological processes which require high-temperature heating (e.g. food industry or pastries).

Administration of repeatedly heated coconut oil alters lipid levels and antioxidant status in cholesterol fed rats

BACKGROUND: Oxidation products generated during repeated heating of cooking oils can participate in the development of cardiovascular diseases. OBJECTIVE: The purpose of the study was to investigate the effects of administration of high fat diet with and without cholesterol and to compare the effects of fresh and repeatedly heated coconut oil in rats. The effects of various diets containing coconut oil on lipid levels in serum and tissues, oxidative damage and antioxidant status in tissues were studied. METHODS: Coconut oil was heated at 210 ± 10°C for fifteen hours. Male Sprague Dawley rats were divided into four groups of six animals each and were fed the experimental diet for sixty days. RESULTS: Results revealed that rats fed high fat – cholesterol enriched diet significantly influenced the lipid levels and antioxidant status in experimental animals. The results indicate that repeated heating of coconut oil increased the lipid levels and oxidative stress in cholesterol fed rats. CONCLUSIONS: Study demonstrates that thermally stressed dietary oil increases the atherosclerotic tendency in experimental animals by inducing oxidative stress in addition to those induced by dietary cholesterol.

Quality of Lipid Fractions in Deep-Fried Foods from Street Vendors in Chile

Deep-fried foods sold by unlicensed street vendors are a health concern for various reasons, but oil quality is particularly important considering known links between fat consumption and cardiovascular disease. To diagnose the exact gravity of this situation in Chile, a country where street vendors are proliferate, the physicochemical parameters of fat fractions from fried food samples were assessed. Fat quality was assessed through the acidity index, peroxide index, extinction coefficient, TOTOX index, polar compounds percentage, and fatty acid profile. Most food samples (80%) had at least a 10% fat content. Many samples also had high peroxide values (1.7–103.3 meqO2/kg) and extinction coefficients (K232 and K270), findings indicative of advanced oil deterioration. These results were supported by values for para-anisidine (100.2–311.0), TOTOX (>103.6), and polar compounds (14.2–49.7%). All assessed food samples contained saturated, monounsaturated, and polyunsaturated fatty acids, as well as trans-fatty acids (0.6–1.7%). According to national regulations on polar compounds, 50% of the assessed food samples are unfit for human consumption. When applying national limits for C18, all food samples should be discarded. These findings stress the urgent need to strictly control deep-fried foods sold by street vendors.

Frying stability of sunflower oil blended with jujube (Ziziphus mauritiana Lam.) leaf extract

The aim of present study was to compare the effects of ultrasound‐assisted and microwave‐assisted extraction with solvent extraction method on antioxidant activities of jujube (Ziziphus mauritiana Lam.) leaf extracts in stability of sunflower oil during deep frying. The antioxidant activities of the extracts were evaluated by using 2, 2‐diphenyl‐1‐picrylhydrazyl (DPPH˙) radical scavenging and β‐carotene bleaching assays. Ultrasound‐assisted extraction was the most effective method on antioxidant activities of extracts and extraction yield of phenolic compounds compared to other extraction techniques. Protective effect of methanol–water extract of jujube leaf obtained with ultrasound‐assisted extraction (ULMW) at 500 and 700 ppm in stability of sunflower oil was compared to synthetic antioxidants by measuring total polar compounds (TPC), carbonyl value (CV), peroxide value (PV), free fatty acids (FFA), oxidative stability index (OSI), conjugated dienes (CD), and trienes values (CT). Results showed ULMW at 700 ppm had higher stabilization efficiency than synthetic antioxidants.

Use of pilot plant scale continuous fryer to simulate industrial production of potato chips: thermal properties of palm olein blends under continuous frying conditions

Binary blends of palm olein (PO) with sunflower oil (SFO), canola oil (CNO), and cottonseed oil (CSO) were formulated to assess their stability under continuous frying conditions. The results were then compared with those obtained in PO. The oil blends studied were: (1) 60:40 for PO + SFO; (2) 70:30 for PO + CNO; and (3) 50:50 for PO + CSO. The PO and its blends were used to fry potato chips at 180°C for a total of 56 h of operation. The evolution of analytical parameters such as tocols, induction period, color, p-anisidine value, free fatty acid, smoke point, polar compounds, and polymer compounds were evaluated over the frying time. Blending PO with unsaturated oils was generally proved to keep most qualitative parameters comparable to those demonstrated in PO. Indeed, none of the oils surpassed the legislative limits for used frying. Overall, it was noted that oil containing PO and SFO showed higher resistance toward oxidative and hydrolytic behaviors as compared to the other oil blends.

Thermal degradation of groundnut oil during continuous and intermittent frying

The quality of refined groundnut oil, as affected by frying Poori, was assessed with respect to two types of frying operations viz., continuous frying and intermittent frying. Continuous frying was carried out consistently for 8 h, whereas intermittent frying was performed for 2 h everyday for 4 days for a total of 8 frying hours. The purpose of the study was to compare the level of deterioration that occurred during the two operations. Among the parameters studied, peroxide value (11.3 ± 0.26 meqO2/kg), anisidine value (172.4 ± 2.71), diene value (1.57 ± 0.095), oxidized fatty acid (2.6 ± 0.17%) and viscosity (103.8 ± 2.5 mPa s(-1)), were found to be higher after 8 h due to intermittent frying. The corresponding values 4.9 ± 0.15, 133.3 ± 0.49, 0.811 ± 0.04, 0.38 ± 0.023 and 81.8 ± 2.02 were observed in continuous frying. Parameters such as iodine value, unsaturated fatty acids, saponification value and smoke point decreased significantly (P < 0.5) due to intermittent frying. Results showed that intermittent frying caused more quality degradation to GNO than continuous frying.

Maldi-tof mass spectrometry profiling of polar and nonpolar fractions in heated vegetable oils

Triacylglycerol oxidation of thermally stressed (6 h at 180 degrees C, simulating deep-frying conditions) edible vegetable oil (sunflower and olive) was studied using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS). Chromatographic separation of the nonpolar and polar components from the heated oil performed on silica gel prior to MS analysis significantly enhanced the detection of oxidized components. The spectra contained signals that were assigned to triacylglycerols (TAG), diacylglycerols (DAG), triacylglycerol oxidative dimers, oxidized TAG, and TAG fragments arising from the homolytic beta-scission of linoleyl, peroxy, and alkoxy radicals. Enrichment of the polar compounds prevented mass spectrometric ion suppression, thus allowing the detection of minor species originating from thermal oxidation. In addition, this allowed the monitoring of polar compounds in vegetable oils undergoing mild thermal treatment. As such, chromatographic separation coupled with MALDI-TOF MS analysis provided a rapid, sensitive, and specific tool to assess the thermal oxidation of vegetable oils.