Antioxidant Efficacy of Rosemary Extract in Improving the Oxidative Stability of Rapeseed Oil during Storage

Rapeseed oil is an important source of edible oil in the human diet and is also highly susceptible to oxidative deterioration. It has been demonstrated that rosemary extract (RE) can increase the oxidative stability of oils. In this work, the antioxidant capacity of rapeseed oil after the addition of RE during storage and the optimum addition of RE in rapeseed oil were investigated. Oxidative stability evaluation results demonstrate that the shelf life of rapeseed oil with the incorporation of 100 mg/kg of RE was equivalent to that with the addition of 50 mg/kg of tert-butyl hydroxyquinone (TBHQ). Storage test analysis results show that RE remarkably delayed the oxidation of rapeseed oil when the storage container was unsealed. The optimum amount of RE as an addition was 50-200 mg/kg under room temperature storage, while it was 150 mg/kg under Schaal oven storage. The antioxidant capacity of rapeseed oil with 50 mg/kg of RE added was remarkably higher than that with 50 mg/kg of TBHQ added after 20 d of storage, according to the Schaal oven test. Additionally, the addition of RE delayed the degradation of endogenous α-tocopherol in rapeseed oil. This study comprehensively evaluated the antioxidant properties of rapeseed oil when RE was added and it provides a new strategy for establishing healthy, nutritious, and safe oil preservation measures.

Synthesis, Characterization and Evaluation of a Novel Tetraphenolic Compound as a Potential Antioxidant

A novel antioxidant containing four hydroxyl groups, namely 2,2'-(2-methylpropane-1,3-diyl)bis(hydroquinone) (MPBHQ), was synthesized using hydroquinone and methylallyl alcohol as the raw materials, phosphoric acid as the catalyst, and toluene as the solvent system. The structure of MPBHQ was characterized by mass spectrometry, nuclear magnetic resonance, ultraviolet spectroscopy, and infrared spectroscopy. The results showed that MPBHQ has a good radical scavenging effect, as measured by the ORAC assay, DPPH radical scavenging assay, ABST radical scavenging assay, and Rancimat test. In fatty acid methyl ester and lard without exogenous antioxidants, MPBHQ showed better antioxidant performance than butylated hydroxytoluene (BHT), hydroquinone (HQ), tert-butyl hydroquinone (TBHQ), and propyl gallate (PG), meeting the need for a new antioxidant with better properties to ensure the oxidative stability of lipids and biodiesel.

Alarming impact of the excessive use of tert-butylhydroquinone in food products: A narrative review

Tert-butyl hydroquinone (TBHQ) is a food additive commonly used as a more effective protectant in the food, cosmetic and pharmaceutical industries. However, the long-term exposure to TBHQ at higher doses (0.7 mg/kg) results in substantial danger to public health and brings a series of side effects, including cytotoxic, genotoxic, carcinogenic, and mutagenic effects. As a result, the global burden of chronic diseases has fascinated consumers and governments regarding the safety assessment of food additives. Regarding contradictory reports of various research about the application of food additives, the accurate monitoring of food additives is urgent. Notwithstanding, there are reports of the therapeutic effects of TBHQ under pathologic conditions through activation of nuclear factor erythroid 2-related factor 2. Thus, further investigations are required to investigate the impact of TBHQ on public health and evaluate its mechanism of action on various organs and cells. Therefore, this review aimed to investigate TBHQ safety through an overview of its impacts on different tissues, cells, and biological macromolecules as well as its therapeutic effects under pathologic conditions.

Synthetic phenolic antioxidants: Metabolism, hazards and mechanism of action

Synthetic phenolic antioxidants can interact with peroxides produced by food. This paper reviews correlation between BHA, BHT and TBHQ metabolism and harms they cause and provides a theoretical basis for rational use of BHA, BHT and TBHQ in food, and also put some attention on the transformation and metabolic products of PG. We introduce BHA, BHT, TBHQ, PG and their possible metabolic pathways, and discuss possible harms and their specific mechanisms responsible. Excessive addition or incorrect use of synthetic phenolic antioxidants results in carcinogenicity, cytotoxicity, oxidative stress induction and endocrine disrupting effects, which warrant attention. BHA carcinogenicity is related to production of metabolites TBHQ and TQ, and cytotoxic effect of BHA is the main cause of apoptosis induction. BHT carcinogenicity depends on DNA damage degree, and tumour promotion is mainly related to production of quinone methylation metabolites. TBHQ carcinogenicity is related to induction of metabolite TQ and enzyme CYP1A1.

Antioxidants Effect of Two Aminomethyl Derivatives of 2-Methoxyphenol on Thermal and Storage Oxidative Stability of Coconut Oil

The antioxidants effect of two aminomethyl derivatives of 2-methoxyphenol: 4,6-di[(morpholin-4-yl)methyl]-2-methoxyphenol (DMMMP) and 5-[(pyrrolidin-1-yl)methyl]vanillic acid (PMVA) on enhancing thermal and oxidative storage stability of coconut oil was performed using tert-butylhydroxyquinone (TBHQ) as a comparative standard. The efficacy on thermal stability test was carried out by heating at 180 oC for 1, 3, and 6 hours, while the efficacy on the storage stability test was performed using an accelerated method by heating at 60oC for 5 weeks. The concentrations for MDMMP was 200, 350, and 500 ppm; for PMVA was 200, 275, and 350 ppm; and for TBHQ was 200 ppm. Free fatty acid (FFA) level, peroxide value (PV), and p-anisidine value (p-AV) were used as parameters to assess the level of oxidative stability of coconut oil. The results showed that the addition of DMMMP 200, 350, and 500 ppm, and PMVA 200 and 275 ppm did not inhibit FFA, peroxide, and aldehyde formation. In thermal stability study, PMVA (350 ppm) could inhibit the free fatty acid release, and formation of secondary oxidation products compounds on thermal stability comparable to TBHQ (200 ppm) addition, but only TBHQ that could inhibit peroxide formation for 6 h. In storage stability, DMMMP (all concentration) could not delay the fatty acid release, while PMVA (all concentration) and TBHQ (200 ppm) delayed that for 2 and 5 weeks, respectively. DMMMP (all concentration) delayed peroxide formation for 2 weeks, while PMVA (all concentration) and TBHQ (200 ppm) delayed peroxide formation for 5 weeks. All compounds only delay the formation of secondary oxidation products for 1 week. In conclusion, the efficacy of PMVA as an antioxidant against thermal and storage oxidative stability of coconut oil is higher than DMMMP but lower than TBHQ.

Identification and assessment of residual levels of the main oxidation product of tert-butylhydroquinone in frying oils after heating and its cytotoxicity to RAW 264.7 cells

tert-Butylhydroquinone (TBHQ) losses and the residual levels of 2-tert-butyl-1,4-benzoquinone (TBBQ) in tripalmitin at different heating temperatures with or without reflux over various time intervals were investigated. Heating at 120 °C resulted in the slowest TBHQ loss and the highest TBBQ levels (52.61-62.93 μg/mL). The highest TBBQ concentrations (111.73-164.67 μg/mL) at 5 and 8 h and residual concentrations of 10.23-46.95 μg/mL during heating at 170 °C over 24 h were observed. Furthermore, the potential cytotoxicity of TBBQ to RAW 264.7 cells was evaluated with the MTT assay, Hoechst 33258 staining test, and flow cytometry analysis. Results indicate that TBBQ dose- and time-dependently decreased the growth of cells and inhibited DNA synthesis by regulating the S/G2 transition. The TBBQ concentration giving 50% inhibition in RAW 264.7 cells was 10.71 μg/mL. This threshold value is lower than the residual level of TBBQ in oil, indicating the necessity for concerns over the safety of fried food in terms of TBBQ residues.