The Effect of High-Temperature Heating on Amounts of Bioactive Compounds and Antiradical Properties of Refined Rapeseed Oil Blended with Rapeseed, Coriander and Apricot Cold-Pressed Oils

Cold-pressed oils are rich sources of bioactive substances, which may protect triacylglycerols from degradation during frying. Nevertheless, these substances may decompose under high temperature. This work considers the content of bioactive substances in blends and their changes during high-temperature heating. Blends of refined rapeseed oil with 5% or 25% in one of three cold-pressed oils (rapeseed, coriander and apricot) were heated at 170 or 200 °C in a thin layer on a pan. All non-heated blends and cold-pressed oils were tested for fatty acid profile, content and composition of phytosterols, tocochromanols, chlorophyll and radical scavenging activity (RSA) analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assays. Moreover, the stability of phytosterols, tocochromanols, DPPH and ABTS values was determined in heated blends. All tocochromanols were lost during the heating process, in particular, at 200 °C. However, there were some differences between homologues. α-Tocopherol and δ-tocopherol were the most thermolabile and the most stable, respectively. Phytosterols were characterized by very high stability at both temperatures. We observed relationships between ABTS and DPPH values and contents of total tocochromanols and α-tocopherol. The obtained results may be useful in designing a new type of fried food with improved health properties and it may be the basis for further research on this topic.

Quality and stability of frying oils and fried foods in ultrasound and microwave-assisted frying processes and hybrid technologies

Frying is a popular cooking method that produces delicious and crispy foods but can also lead to oil degradation and the formation of health-detrimental compounds in the dishes. Chemical reactions such as oxidation, hydrolysis, and polymerization contribute to these changes. In this context, emerging technologies like ultrasound-assisted frying (USF) and microwave (MW)-assisted frying show promise in enhancing the quality and stability of frying oils and fried foods. This review examines the impact of these innovative technologies, delving into the principles of these processes, their influence on the chemical composition of oils, and their implications for the overall quality of fried food products with a focus on reducing oil degradation and enhancing the nutritional and sensory properties of the fried food. Additionally, the article initially addresses the various reactions occurring in oils during the frying process and their influencing factors. The advantages and challenges of USF and MW-assisted frying are also highlighted in comparison to traditional frying methods, demonstrating how these innovative techniques have the potential to improve the quality and stability of oils and fried foods.

Color Reversion of Refined Vegetable Oils: A Review

During the transport, storage, and consumption of edible vegetable oils, the color of some freshly refined oils is gradually darkened, which is known as the color reversion. The oil industry has been plagued by the issue for a long time because the dark color of the oil is related to its poor quality and low acceptability for consumers. Color reversion of refined vegetable oils is primarily related to the processing pigments, especially tocored, which is the oxidation product of γ-tocopherol. However, the underlying molecular action mechanism of tocored is not yet fully understood due to the complex transformations of tocored in oil systems. This paper presents a brief description of oil color, followed by an overview of research progress on the mechanism of color reversion. In particular, the effect of minor components (phospholipids and metal ions) on color reversion is highlighted in an attempt to explain the remaining mysteries of color reversion. Furthermore, the measures to restrain color reversion by quality control of the oilseeds, the adjustment of technical parameters of processing, and the storage conditions of refined oils are summarized to provide some references for the oil industry.

Activity and Characterization of Tocopherol Oxidase in Corn Germs and Its Relationship with Oil Color Reversion

Color reversion has long been a major problem for the vegetable oil industry, and the enzymatic oxidation of γ-tocopherol is thought to trigger this phenomenon. In this study, first, the extraction, purification, and detailed characterization of tocopherol oxidase from fresh corn germs were performed. Then, the relationship between the enzyme reaction of γ-tocopherol and oil color reversion was verified. The results showed that the membrane-free extracts of raw corn germ performed specific catalysis of tocopherol in the presence of lecithin. In terms of the oxidation product, tocored (the precursor of color reversion) was detected in the mixture after the catalytic reactions, indicating that this anticipated enzyme reaction was probably correlated with the color reversion. Furthermore, the optimal pH and temperature for the tocopherol oxidase enzyme were 4.6 and 20 °C, respectively. In addition, ascorbic acid at 1.0 mM completely inhibited the enzymatic reaction.

Evaluation of the functional quality of rapeseed oil obtained by different extraction processes in a Sprague-Dawley rat model

The nutritional function of vegetable oil is influenced by different oil extraction methods. In this study, the effects of different processing techniques on the quality of rapeseed oil and animal lipid metabolism were evaluated. Results showed that rapeseed oil obtained by the aqueous enzymatic extraction (AEE) method had the highest polyphenol (152.08 ± 11.44 mg GAE per kg), α-tocopherol (208.97 ± 15.84 mg kg-1), and β-carotene (5.40 mg kg-1) contents and a better oxidation resistance. It was noted in an experiment on rats fed with diets containing rapeseed oils that AEE rapeseed oil reduces total cholesterol (TC), triacylglycerol (TG), low-density lipoprotein cholesterol (LDL-C), aspartate transaminase (ALT) and alanine transaminase (AST) in high-fat diet rats by 27.09%, 11.81%, 35.52%, 31.02% and 27.61%, respectively, and the body and liver weights of rats were decreased. mRNA expression indicated that AEE could significantly down-regulate fatty acid synthase (FAS) and up-regulate acyl-CoA oxidase 1 (ACOX1) gene expression levels (P < 0.05). These results suggested that the AEE method can increase the content of trace active substances in rapeseed oil and ameliorate chronic diseases induced by a high-fat diet.

Analysis of Cannabinoid-Containing Fluids in Illicit Vaping Cartridges Recovered from Pulmonary Injury Patients: Identification of Vitamin E Acetate as a Major Diluent

Beginning in June of 2019, there was a marked increase in reported cases of serious pulmonary injury associated with vaping. The condition, referred to as e-cigarette or vaping product use-associated lung injury (EVALI), does not appear to involve an infectious agent; rather, a chemical adulterant or contaminant in vaping fluids is suspected. In August of 2019, the Wadsworth Center began receiving vaporizer cartridges recovered from patients with EVALI for analysis. Having no a priori information of what might be in the cartridges, we employed untargeted analyses using gas chromatography-mass spectrometry and high-resolution mass spectrometry to identify components of concern. Additionally, we employed targeted analyses used for New York medical marijuana products. Here, we report on the analyses of 38 samples from the first 10 New York cases of EVALI for which we obtained cartridges. The illicit fluids had relatively low cannabinoid content, sometimes with unusual Δ9-/Δ8-tetrahydrocannabinol ratios, sometimes containing pesticides and many containing diluents. A notable diluent was α-tocopheryl acetate (vitamin E acetate; VEA), which was found in 64% of the cannabinoid-containing fluids. To investigate potential sources of the VEA, we analyzed six commercial cannabis-oil diluents/thickeners. Three were found to be >95% VEA, two were found to be primarily squalane, and one was primarily α-bisabolol. The cause(s) of EVALI is unknown. VEA and squalane are components of some personal care products; however, there is growing concern that vaping large amounts of these compounds is not safe.

Identification of α-Tocopherol and Its Oxidation Products by Ultra-Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry

This study aimed to determine α-tocopherol (α-T) and its thermal oxidation products simultaneously. A novel method based on an ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was developed. This approach was achieved by means of a BEH C18 analytical column under gradient elution conditions with eluents of acetonitrile/isopropanol (1:9, v/v) and acetonitrile/water (4:6, v/v). Compounds were elucidated through exact molecular mass and fragmentation ions obtained from the Q-TOF-MS detector. Two oxidation products, α-tocopheryl quinone and 5-formyl-γ-tocopherol, were identified, and one new compound was determined. This approach offered a simple, precise, and reliable method to determine oxidation products of α-T, which may give a way to understand the mechanism of the thermal oxidative process of α-T.

Novel and rare prenyllipids - Occurrence and biological activity

The data presented indicate that there is a variety of unique prenyllipids, often of very limited taxonomic distribution, whose origin, biosynthesis, metabolism and biological function deserves to be elucidated. These compounds include tocoenols, tocochromanol esters, tocochromanol acids, plastoquinones and ubiquinones. Additionally, based on the available data, it can be assumed that there are still unrecognized prenyllipids, like prenylquinols fatty acid esters of the hydroquinone ring, including prenylquinol phosphates, and others, whose biological function might be of great importance. Our knowledge of these compounds is not only important from the scientific point of view, but may also be of practical significance to medicine, pharmacy or cosmetics.