Biohazard and dynamic features of different polar compounds in vegetable oil during thermal oxidation

The role of β2-AR/PI3K/AKT pathway in the proliferation, migration and invasion of THLE-2 cells induced by nicotine

Nicotine, the primary constituent of tobacco, is one of the important factors that induce the occurrence of hepatocellular carcinoma (HCC). The β2-adrenergic receptor (β2-AR) is implicated in the growth and advancement of tumors. However, the role of β2-AR and its mediated cascades in nicotine-induced HCC remains unclear. This present study aims to observe the effects of nicotine on the proliferation, migration, and invasion of immortalized human liver epithelial (THLE-2) cells, as well as to explore the underlying mechanisms of action. The results of cell counting kit-8 (CCK-8) assay showed that 0.3125 μM nicotine had the ability to promote the proliferation of THLE-2 cells with a significant time-dependent manner. Therefore, THLE-2 cells were mainly selected for chronic treatment with 0.3125 μM nicotine in the later stage to cause transformation. After 30 passages of THLE-2 cells with 0.3125 μM nicotine treatment, chronic exposure to nicotine significantly enhanced the proliferation, metastasis, and invasion of cells. Besides, it also upregulated the intracellular levels of β2-AR, phosphoinositide 3-kinase (PI3K), AKT, matrix metalloproteinase-2 (MMP-2) and Cyclin D1, as well as downregulated the expression of p53. More importantly, the β2-AR/PI3K/AKT pathway was found to mediate the expression of MMP-2, Cyclin D1, and p53 in THLE-2 cells, playing a crucial role in their proliferation, migration, and invasion after continuous exposure to nicotine. Simply put, it demonstrated the role of β2-AR/PI3K/AKT pathway in the transformation of THLE-2 cells induced by nicotine. This study could provide valuable insights into the relationship between nicotine and HCC. Additionally, it lays the groundwork for investigating potential anticancer treatments for liver cancer linked to tobacco consumption.

Study by means of 1H nuclear magnetic resonance of the oxidation process in high oleic sunflower oil and palm oil during deep-frying of fish cakes

This study aimed to compare the frying performance of palm oil (PO) and high oleic sunflower oil (HOSO) during frying aquatic products. The quality change and frying performance of HOSO and PO during frying of fish cakes were investigated. The oxidation and hydrolysis products of both oils were explored by the nuclear magnetic resonance technique. The results showed that the color deepening rate of PO was higher than that of HOSO. After 18 h of frying, the total polar compound content of PO and HOSO reached 25.67% and 27.50%, respectively. HOSO had lower degree of oxidation than PO after 24 h of continuous frying. The polyunsaturated fatty acid content in HOSO and PO significantly decreased. The oleic acid content in HOSO remained above 80% during the frying process. The major aldehydes in both oils were (E, E)-2,4-alkadienals and n-alkanals and glycerol diesters (DAGs) were abundant in PO. Furthermore, the addition of fish cakes had slight effect on the quality of the frying oil. Therefore, HOSO is an appropriate candidate for frying owing to its excellent frying stability and nutritional value.

Oxidative lipidomics to elucidate the non-volatile derivatives of four typical triglycerides in vegetable oils under simulated frying conditions

Vegetable oils with different saturations have varied composition of triglycerides (TGs) and produce different non-volatile derivatives during oxidation. Precise characterization of the non-volatile derivatives of TGs is essential for understanding the degradation of TGs and the production pattern of non-volatile derivatives. Oxidative lipidomics was combined with collision-induced dissociation and electron-activated dissociation to elucidate the precise structures of non-volatile derivatives produced under simulated frying conditions by 1,3-dipalmitoyl-2-oleoylglycerol (POP), triolein (OOO), trilinolein (LLL), and trilinolenin (LnLnLn). The results indicate that the unsaturated fatty acyl chains at the sn-2 position were more susceptible to oxidation compared with those at the sn-1/3 position. Species of non-volatile derivatives included epoxy-, hydroperoxy-, hydroxy-, and oxo-TGs, as well as degradation products. The potential reaction pathways of TGs and their non-volatile derivatives were also proposed. This study elucidated oxidative degradation mechanisms of the four typical TGs and provided a theoretical basis for changes of vegetable oils during frying.

Oil Penetration of Batter-Breaded Fish Nuggets during Deep-Fat Frying: Effect of Frying Oils

Four frying oils (rapeseed, soybean, rice bran, and palm oils) were employed either as received (fresh) or after preheating at 180 °C for 10 h, and measured for their fatty acid composition, viscosity, and dielectric constant. Batter-breaded fish nuggets (BBFNs) were fried at 180 °C (60 s), and the effect of the oils’ quality on the oil penetration of fried BBFNs were investigated via the analysis of the absorption and the distribution of fat. Preheating increased the viscosity and dielectric constant of the oils. The total fat content using fresh oils was the greatest for palm oil (14.2%), followed by rice bran oil (12.2%), rapeseed oil (12.1%), and soybean oil (11.3%), a trend that was nearly consistent with the penetrated surface oil, except that the penetrated oil for soybean oil (6.8%) was higher than rapeseed oil (6.3%). The BBFNs which were fried using fresh oils possessed a more compact crust and smaller pores for the core and underwent a lower oil penetration compared to the preheated oils. The results suggested that the oils’ quality significantly affected the oil penetration of fried BBFNs.

Simultaneous Determination of Aflatoxins and Benzo(a)pyrene in Vegetable Oils Using Humic Acid-Bonded Silica SPE HPLC–PHRED–FLD

In the present work, a rapid, accurate, and cost-effective method was developed for the simultaneous quantification of aflatoxins and benzo(a)pyrene in lipid matrices, using solid-phase extraction (SPE) via humic acid-bonded silica (HAS) sorbents, followed by high-performance liquid chromatography coupled with photochemical post-column reactor fluorescence spectroscopy (HPLC–PHRED–FLD) analysis. The major parameters of extraction efficiency and HPLC–PHRED–FLD analysis were investigated and this method was fully validated. The limits of quantification and the limits of detection were 0.05–0.30 and 0.01–0.09 µg kg⁻¹, respectively. The recoveries were 66.9%–118.4% with intra-day and inter-day precision less than 7.2%. The results of 80 oil samples from supermarkets indicated a high occurrence of BaP, and most of concentrations were within the requirements of EU and China food safety regulations. This is the first utilization of HAS–SPE HPLC–PHRED–FLD to simultaneously analyze the occurrence of aflatoxins and benzo(a)pyrene in vegetable oils.

Application of Artificial Neural Network Based on Traditional Detection and GC-MS in Prediction of Free Radicals in Thermal Oxidation of Vegetable Oil

In this study, electron paramagnetic resonance (EPR) and gas chromatography-mass spectrometry (GC-MS) techniques were applied to reveal the variation of lipid free radicals and oxidized volatile products of four oils in the thermal process. The EPR results showed the signal intensities of linseed oil (LO) were the highest, followed by sunflower oil (SO), rapeseed oil (RO), and palm oil (PO). Moreover, the signal intensities of the four oils increased with heating time. GC-MS results showed that (E)-2-decenal, (E,E)-2,4-decadienal, and 2-undecenal were the main volatile compounds of oxidized oil. Besides, the oxidized PO and LO contained the highest and lowest contents of volatiles, respectively. According to the oil characteristics, an artificial neural network (ANN) intelligent evaluation model of free radicals was established. The coefficients of determination (R2) of ANN models were more than 0.97, and the difference between the true and predicted values was small, which indicated that oil profiles combined with chemometrics can accurately predict the free radical of thermal oxidized oil.