Effect of enzymatic Maillard reaction conditions on physicochemical properties, nutrition, fatty acids composition and key aroma compounds of fragrant rapeseed oil.

BACKGROUND: A new enzymatic hydrolysis-based process inspired by the Maillard reaction can produce strong flavored, high-value rapeseed oil that meets safety requirements. In the present study, the effect of reaction time (10-30 min) and temperature (130-160 °C) on the physicochemical properties, nutritional status, fatty acids composition and key aroma compounds of fragrant rapeseed oil (FRO) was investigated. RESULTS: An increasing reaction time and temperature substantially decreased the total tocopherol, polyphenol and sterol contents of FRO, but increased benzo[a]pyrene content, as well as the acid and peroxide values, which did not exceed the European Union legislation limit. Among the volatile components, 2,5-dimethyl was the main substance contributing to the barbecue flavor of FRO. The 150 °C for 30 min reaction conditions produced a FRO with a strong, fragrant flavor, with high total tocopherol (560.15 mg kg-1 ), polyphenol (6.82 mg kg-1 ) and sterol (790.65 mg kg-1 ) contents; acceptable acid (1.60 mg g-1 ) and peroxide values (4.78 mg g-1 ); and low benzo[a]pyrene (1.39 mg g-1 ) content. These were the optimal conditions for the enzymatic Maillard reaction, according to the principal component analysis. Furthermore, hierarchical cluster analysis showed that reaction temperature had a stronger effect on FRO than reaction time. CONCLUSION: The optimal enzymatic Maillard reaction conditions for the production of FRO are heating at 150 °C for 30 min. These findings provide new foundations for better understanding the composition and flavor profile of FRO, toward guiding its industrial production. © 2023 Society of Chemical Industry.

Glucosinolates or erucic acid, which one contributes more to volatile flavor of fragrant rapeseed oil?

This study aims to investigate the effect of three rapeseed varieties with different erucic acid (EA) and glucosinolates (GLSs) content, and different degumming methods on the volatile flavor profiles of fragrant rapeseed oil (FRO). A total of 171 volatile compounds were identified by headspace solid-phase microextraction combine with gas chromatography-mass spectrometry (HS-SPME/GC-MS), and 87 compounds were identified as key odorants owing to their relative odor activity values (ROAV) ≥ 1. Methyl furfuryl disulfide was identified in rapeseed oil for the first time, with highest ROAVs (up to 26805.46). The volatile flavor profile of rapeseed oil was affected by GLSs content to a certain extent rather than EA content. Rapeseed varieties with low-EA and high-GLSs are suitable to produce FRO. Silicon dioxide adsorbing was an effective alternative method to water degumming in FRO. This work provided a new idea for selection of raw materials and degumming methods in FRO production.

Polyphenolic compounds from rapeseeds (Brassica napus L.): The major types, biofunctional roles, bioavailability, and the influences of rapeseed oil processing technologies on the content.

The rapeseed (Brassica napus L.) are the important oil bearing material worldwide, which contain wide variety of bioactive components with polyphenolic compounds considered the most typical. The rapeseed polyphenols encompass different structural variants, and have been considered to have many bioactive functions, which are beneficial for the human health. Whereas, the rapeseed oil processing technologies affect their content and the biofunctional activities. The present review of the literature highlighted the major types of the rapeseed polyphenols, and summarized their biofunctional roles. The influences of rapeseed oil processing technologies on these polyphenols were also elucidated. Furthermore, the directions of the future studies for producing nutritional rapeseed oils preserved higher level of polyphenols were prospected. The rapeseed polyphenols are divided into the phenolic acids and polyphenolic tannins, both of which contained different subtypes. They are reported to have multiple biofunctional roles, thus showing outstanding health improvement effects. The rapeseed oil processing technologies have significant effects on both of the polyphenol content and activity. Some novel processing technologies, such as aqueous enzymatic extraction (AEE), subcritical or supercritical extraction showed advantages for producing rapeseed oil with higher level of polyphenols. The oil refining process involved heat or strong acid and alkali conditions affected their stability and activity, leading to the loss of polyphenols of the final products. Future efforts are encouraged to provide more clinic evidence for the practical applications of the rapeseed polyphenols, as well as optimizing the processing technologies for the green manufacturing of rapeseed oils.

Research progress and future study on physicochemical, nutritional, and structural characteristics of canola and rapeseed feedstocks and co-products from bio-oil processing and nutrient modeling evaluation methods.

This article aims to review research progress and provide future study on physicochemical, nutritional, and molecular structural characteristics of canola and rapeseed feedstocks and co-products from bio-oil processing and nutrient modeling evaluation methods. The review includes Canola oil seed production, utilization and features; Rapeseed oil seed production and canola oil seed import in China; Bio-processing, co-products and conventional evaluation methods; Modeling methods for evaluation of truly absorbed protein supply from canola feedstock and co-products. The article provides our current research in feedstocks and co-products from bio-oil processing which include Characterization of chemical and nutrient profiles and ruminal degradation and intestinal digestion; Revealing intrinsic molecular structures and relationship between the molecular structure spectra features and nutrient supply from feedstocks and co-products using advanced vibrational molecular spectroscopy technique. The study focused on advanced vibrational molecular spectroscopy which can be used as a fast tool to study molecular structure features of feedstock and co-products from bio-oil processing. The article also provides future in depth study areas. This review provides an insight as how to use advanced vibrational molecular spectroscopy for in-depth analysis of the relationship between molecular structure spectral feature and nutrition delivery from canola feedstocks and co-products from bio-oil processing.

Water content, critical micelle concentration of phospholipids and formation of association colloids as factors influencing autoxidation of rapeseed oil.

BACKGROUND: The exact mechanism of lipid autoxidation in vegetable oils, taking into account physical aspects of this phenomenon, including the role of association colloids, is still not fully understood. The purpose of this study was to consider changes in moisture content and DOPC phospholipid (1,2-dioleoyl-sn-glycero-3-phosphocholine) critical micelle concentration (CMC) in rapeseed oil during autoxidation as well as to find the relationship between these parameters and the accumulation of primary and secondary lipid oxidation products. RESULTS: The experiments were performed at initial oil humidity 220 ppm and 700 ppm, with DOPC below and above CMC. The increase in water concentration was favored by the presence of phospholipids above CMC and, at the same time, high initial water level, which favored oxidation processes and the creation of amphiphilic autoxidation products. At relatively high water level and low amphiphilic DOPC concentration, the growth of water content does not affect the concentration of oxidation products. CONCLUSION: Amphiphilic substances play a significant role in increasing the water content of oil. Autoxidation products may reduce CMC of DOPC, but water is able to compensate for the CMC-reducing effect of oxidation products. The presence of association colloids and initial water content play a crucial role in the oxidation process of rapeseed oil. The increase in water concentration does not cause a sufficiently large increase in the number of micelles or sufficiently significant changes in their structure to effect an increase in the level of oxidation products. The formation of micelles requires an appropriate content of both water and amphiphilic substances derived from seeds (phospholipids). © 2021 Society of Chemical Industry.

Influence of extraction technology on rapeseed oil functional quality: a study on rapeseed polyphenols.

Extraction technology can influence the vegetable oil functional quality. Polyphenols in rapeseed oil have been proved to be beneficial for cardiovascular health. In this study, we evaluated the effect of extraction methods on the functional quality of rapeseed oil from the perspective of phenolic compounds. The results showed that hot pressing produces the highest amount of phenolic compounds in rapeseed oil. Its most abundant phenolic compound, sinapine (9.18 µg g-1), showed the highest activity in inhibiting anaerobic choline metabolism with an EC50 value of 1.9 mM, whose downstream products are related to cardiovascular diseases. Molecular docking and molecular dynamics (MD) simulations revealed that sinapine exhibits good binding affinity toward CutC, and CutC-sinapine is a stable complex with fewer conformational fluctuations and similar tightness. Taken together, hot pressing can be considered the best extraction method for rapeseed oil from the perspective of phenolic compounds.

Investigation on the surface-active and antimicrobial properties of a natural glycolipid product.

Glycolipids are a group of sugar-containing lipids with versatile functions. In this study, a natural glycolipid product was obtained from soy lecithin, and its emulsifying, oil-gelling, antibacterial and antiviral properties were investigated. A silica-based extraction method on a preparative scale was used to recover the glycolipid product (GLP) from soy lecithin. The GLP consisted of three different glycolipid classes: acylated sterol glucoside (64.16%), sterol glucoside (25.57%) and cerebroside (6.71%). As an emulsifier, the GLP was able to form a stable water-in-oil emulsion. The GLP exhibited a good oil-gelling property, capable of gelling rapeseed oil at a concentration of 6%. For the investigated microorganisms (Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus), the GLP did not show any antibacterial effects. The GLP exerted antiviral activity against lentivirus, but not adenovirus. The results of this study help in enriching the knowledge on the properties of naturally occurring glycolipids, which may find potential applications in the food, pharmaceutical and related industries.

Rapid Assessment of Quality Changes in French Fries during Deep-frying Based on FTIR Spectroscopy Combined with Artificial Neural Network.

Fourier transform infrared (FTIR) spectroscopy combined with backpropagation artificial neural network (BP-ANN) were utilized for rapid and simultaneous assessment of the lipid oxidation indices in French fries. The conventional indexes (i.e. total polar compounds, oxidized triacylglycerol polymerized products, oxidized triacylglycerol monomers, triacylglycerol hydrolysis products, and acid value), and FTIR absorbance intensity in French fries were determined during the deep-frying process, and the results showed the French fries had better quality in palm oil, followed by sunflower oil, rapeseed oil and soybean oil. The FTIR spectra of oil extracted from French fries were correlated to the reference oxidation indexes determined by AOCS standard methods. The results of BP-ANN prediction showed that the model based on FTIR fitted well (R2 > 0.926, RMSEC < 0.481) compared with partial least-squares model (R2 > 0.876). This facile strategy with excellent performance has great potential for rapid characterization quality of French fries during frying.

Fully hydrogenated canola oil extends lifespan in stroke-prone spontaneously hypertensive rats.

BACKGROUND: Canola oil (Can) and several vegetable oils shorten the lifespan of stroke-prone spontaneously hypertensive rats (SHRSP). Although similar lifespan shortening has been reported for partially hydrogenated Can, the efficacy of fully hydrogenated oils on the lifespan remains unknown. The present study aimed to investigate the lifespan of SHRSP fed diets containing 10 % (w/w) of fully hydrogenated Can (FHCO) or other oils. METHODS: Survival test: Upon weaning, male SHRSP were fed a basal diet for rodents mixed with one of the test oils -i.e., FHCO, Can, lard (Lrd), and palm oil (Plm) throughout the experiment. The animals could freely access the diet and drinking water (water containing 1 % NaCl), and their body weight, food intake, and lifespan were recorded. Biochemical analysis test: Male SHRSP were fed a test diet with either FHCO, Can, or soybean oil (Soy) under the same condition, except to emphasize effects of fat, that no NaCl loading was applied. Soy was used as a fat source in the basal diet and was set the control group. Blood pressures was checked every 2 weeks, and serum fat levels and histological analyses of the brain and kidney were examined after 7 or 12 weeks of feeding. RESULTS: During the survival study period, the food consumption of FHCO-fed rats significantly increased (15-20 % w/w) compared with that of rats fed any other oil. However, the body weight gain in the FHCO group was significantly less (10-12 %) than that in the control group at 9-11 weeks old. The FHCO (> 180 days) intervention had the greatest effect on lifespan, followed by the Lrd (115 ± 6 days), Plm (101 ± 2 days), and Can (94 ± 3 days) diets. FHCO remarkably decreased the serum cholesterol level compared with Can and the systolic blood pressure from 12 to 16 weeks of age. In addition, while some rats in the Can group exhibited brain hemorrhaging and renal dysfunction at 16 weeks old, no symptoms were observed in the FHCO group. CONCLUSION: This current study suggests that complete hydrogenation decreases the toxicity of Can and even prolongs the lifespan in SHRSP.

Improving the nutritional profile of culinary products: oleogel-based bouillon cubes.

Structured fat phases are the basis of many consumer relevant properties of fat-containing foods. To realise a nutritional improvement - less saturated, more unsaturated fatty acids - edible oleogels could be remedy. The feasibility of traditional fat phases structured by oleogel in culinary products has been evaluated in this study. In this contribution the oleogel application in bouillon cubes as model system for culinary products is discussed. Three different gelators (sunflower wax (SFW), a mixture of ß-Sitosterol and γ-Oryzanol (SO) and ethylcellulose (EC)), at two concentration levels (5% and 10% (w/w)) each, were evaluated with respect to their physical properties, in the food matrix and application. The application of pure and structured canola oil (CO) was benchmarked against the reference, palm fat (PO). The assessment of the prototypes covered attempts to correlate the physicochemical analyses and sensory data. Organoleptic and analytical studies covered storage stability (up to 6 months) monitoring texture, color and fat oxidation. The results indicate that the substitution of palm fat by oleogel is essentially possible. The characteristics of the bouillon cubes are tuneable by gelator choice and inclusion level. Most importantly, the data show that the anticipated risk of intolerable effects of oxidation during shelf life is limited if antioxidants are used.

Effect of infrared ray roasting on oxidation stability and flavor of virgin rapeseed oils.

Effects of infrared ray roasting (IRR) on the oxidation stability and flavors of virgin rapeseed oil (VROs) at 110-170°C were investigated and compared with traditional roller roasting (TRR). Results showed that IRR samples showed lower acid and peroxides values, higher oxidation stability index, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity than TRR ones. IRR samples displayed better thermal expansion of rapeseed for internal fragmentation from microstructures, which facilitated the release of tocophenols (652.63-748.78 mg/kg) and 4-vinylsyringol (7.54-678.19 mg/kg), compared with TRR ones with tocophenols (652.63-689.28 mg/kg) and 4-vinylsyringol (7.54-524.18 mg/kg) contributing to better oxidation stability. Moreover, important volatile compounds, including pyrazines, isothiocyanates, nitriles and aldehydes, were formed quantitatively more in IRR than TRR samples, which was attributed to better heat transfer efficiency and internal fragmentation promoting complex reactions inside rapeseed. Therefore, IRR has more positive roasting effects on VROs than TRR. PRACTICAL APPLICATION: Virgin rapeseed oil is a massively consumed flavor vegetable oil, but the traditional high-temperature roller seed roasting process can cause serious quality problems. Our work applied a novel roasting technology, infrared ray roasting to rapeseed pretreatment. The results show that this new type of roasting technology is more efficient and stable and has important applications in the production of virgin rapeseed oil with better oxidative stability and flavor.

Formulation of Cannabidiol in Colloidal Lipid Carriers.

In this study, the general processability of cannabidiol (CBD) in colloidal lipid carriers was investigated. Due to its many pharmacological effects, the pharmaceutical use of this poorly water-soluble drug is currently under intensive research and colloidal lipid emulsions are a well-established formulation option for such lipophilic substances. To obtain a better understanding of the formulability of CBD in lipid emulsions, different aspects of CBD loading and its interaction with the emulsion droplets were investigated. Very high drug loads (>40% related to lipid content) could be achieved in emulsions of medium chain triglycerides, rapeseed oil, soybean oil and trimyristin. The maximum CBD load depended on the type of lipid matrix. CBD loading increased the particle size and the density of the lipid matrix. The loading capacity of a trimyristin emulsion for CBD was superior to that of a suspension of solid lipid nanoparticles based on trimyristin (69% vs. 30% related to the lipid matrix). In addition to its localization within the lipid core of the emulsion droplets, cannabidiol was associated with the droplet interface to a remarkable extent. According to a stress test, CBD destabilized the emulsions, with phospholipid-stabilized emulsions being more stable than poloxamer-stabilized ones. Furthermore, it was possible to produce emulsions with pure CBD as the dispersed phase, since CBD demonstrated such a pronounced supercooling tendency that it did not recrystallize, even if cooled to -60 °C.

Release Kinetics Studies of Early-Stage Volatile Secondary Oxidation Products of Rapeseed Oil Emitted during the Deep-Frying Process.

The research concerns the use of proton transfer reaction mass spectrometer to track real-time emissions of volatile secondary oxidation products released from rapeseed oil as a result of deep-frying of potato cubes. Therefore, it was possible to observe a sudden increase of volatile organic compound (VOC) emissions caused by immersion of the food, accompanied by a sudden release of steam from a potato cube and a decrease of the oil temperature by more than 20 °C. It was possible to identify and monitor the emission of major secondary oxidation products such as saturated and unsaturated aldehydes, namely acrolein, pentanal, 2-hexenal, hexanal, 2-nonenal and 2-decenal. Each of them has an individual release characteristic. Moreover, the impact of different initial frying temperatures on release kinetics was investigated. Subsequently, it was possible to approximate the cumulative emission by a second-degree polynomial (R2 ≥ 0.994). Using the proposed solution made it possible for the first time to observe the impact of the immersion of food in vegetable oil on the early emission of thermal degradation products oil.

Effect of Sucrose Esterified Fatty Acid Moieties on the Crystal Nanostructure and Physical Properties of Water-in-oil Palm-based Fat Blends.

The effects of sucrose ester of fatty acid (SEF) on the nanostructure and the physical properties of water-in-oil (W/O)-type emulsified semisolid fats were investigated. Model emulsions including palm-based semisolid fats and fully hydrogenated rapeseed oils with 0.5% SEF or fractionated lecithin, were prepared by rapidly cooling crystallization using 0.5% monoacylglycerol as an emulsifier. The SEFs used in this study were functionalized with various fatty acids, namely, lauric, palmitic, stearic, oleic, and erucic acids. Cryogenic transmission electron microscopy (cryo-TEM) was used to observe the sizes of the solvent- extracted nanoplatelets. The solid fat content (SFC), oil migration value, and storage elastic modulus were also determined. The average crystal size, which was measured in length, of the fat blends with SEFs containing saturated fatty acids (namely, palmitic and stearic acids) was smaller than that of the SEFs containing unsaturated fatty acids (namely, oleic and erucic acids). The effects exerted by these fatty acid moieties on the spherulite size in the corresponding bulk fat blends were observed via polarized microscopy (PLM). The results suggest that nanostructure formation upon the addition of SEF ultimately influenced these aggregated microstructures. Generally, smaller platelets resulted in higher SFC in the fat phase, and a high correlation between the SFC and the G' values in W/O emulsion fats was observed (R2 = 0.884) at 30°C. In contrast, the correlation was low at 10℃. Furthermore, samples with larger nanocrystals had a higher propensity for oil migration. Thus, the addition of SEF regulated the fat crystal nanostructure during nucleation and crystal growth, which could ultimately influence the physical properties of commercially manufactured fat products such as margarine.

Enhancement of sophorolipids production in Candida batistae, an unexplored sophorolipids producer, by fed-batch fermentation.

Sophorolipids (SLs) from Candida batistae has a unique structure that contains ω-hydroxy fatty acids, which can be used as a building block in the polymer and fragrance industries. To improve the production of this industrially important SLs, we optimized the culture medium of C. batistae for the first time. Using an optimized culture medium composed of 50 g/L glucose, 50 g/L rapeseed oil, 5 g/L ammonium nitrate and 5 g/L yeast extract, SLs were produced at a concentration of 24.1 g/L in a flask culture. Sophorolipids production increased by about 19% (28.6 g/L) in a fed-batch fermentation using a 5 L fermentor. Sophorolipids production more increased by about 121% (53.2 g/L), compared with that in a flask culture, in a fed-batch fermentation using a 50 L fermentor, which was about 787% higher than that of the previously reported SLs production (6 g/L). These results indicate that a significant increase in C. batistae-derived SLs production can be achieved by optimization of the culture medium composition and fed-batch fermentation. Finally, we successfully separated and purified the SLs from the culture medium. The improved production of SLs from C. batistae in this study will help facilitate the successful development of applications for the SLs.

Evaluation of a quick one-step sample preparation method for the determination of the isotopic fingerprint of rapeseed (Brassica napus): Investigation of the influence of the use of 2,2-dimethoxypropane on compound-specific stable carbon and hydrogen isotope analyses by gas chromatography combustion/pyrolysis isotope ratio mass spectrometry.

RATIONALE: Gas chromatographic analyses for vegetable oils require transesterification, which generally involves multiple steps, mainly to generate fatty acid methyl esters (FAMEs). A quick method based on acid-catalyzed transesterification using 2,2-dimethoxypropane (DMP) enables the conversion in one step, in a single reactor. For compound-specific stable carbon and hydrogen isotope analyses (C- and H-CSIA) of individual fatty acids (FAs) in oil, the verification of this one-step method has not yet been reported. METHODS: In this study, we evaluated the feasibility of the one-step method for C- and H-CSIA of individual FAMEs in rapeseed samples. The focus was on the investigation of the influence of methanol, which was produced from the reactions of DMP with glycerol and water during transesterification, on the accuracy of isotope composition of FAMEs, consequently of the FAs. The reproducibility of the one-step method was assessed by the measurement of the FAMEs from rapeseed and rapeseed oil. For the C- and H-CSIA of individual FAMEs, a gas chromatography combustion/pyrolysis isotope ratio mass spectrometry system was used. RESULTS: Our results showed that no significant differences arise in the carbon and hydrogen isotope compositions of the selected main FAMEs produced with and without DMP except for the H-CSIA value of C18:3. The reproducibility of the one-step method for rapeseed was in the range of ±0.1 mUr to ± 0.3 mUr for C-CSIA and ±1 mUr to ±3 mUr for H-CSIA of the main FAMEs. CONCLUSIONS: DMP improves the transesterification efficiency without influencing the accuracy of the C- and H-CSIA of FAMEs. The performance of the one-step method for rapeseed samples for the determination of C- and H-CSIA values of FAMEs is satisfactory. Thus, the applicability of the one-step method for isotopic fingerprint analyses of FAs in oilseeds is reported for the first time.

Solubility and mass transfer coefficient of oxygen through gas- and water-lipid interfaces.

The solubility of oxygen and its transfer rate to the lipid phase play important roles in lipid oxidation, which affects the taste and safety of lipid-containing foods. In this study, we measured the Henry's constants (solubility) of oxygen for fatty acids, fatty acid esters, and triacylglycerols (TAGs; vegetable oils), as well as the mass transfer coefficients of oxygen at the gas- and water-lipid interfaces. The constants and coefficients were estimated by analyzing the change over time in the oxygen partial pressure or concentration in the closed container based on the mass balance equations of oxygen in the gas and liquid phases. The constant for water obtained by the method used in this study was in agreement with the previously reported value to confirm the validity of the method. The constants for lipids depended on the lipid type, and were higher in the order of fatty acid ester, fatty acid, and TAG. That is, the solubility of oxygen decreased in this order. For all lipids, the constant increased as the number of carbon atoms in the fatty acid chain increased. The constants for fatty acids and their esters were linearly correlated with the enthalpies of evaporation of the lipids. The mass transfer coefficients of oxygen at the gas-liquid interface were on the order of 10-5 m/s for water and methyl dodecanoate and of 10-6 m/s for TAG (rapeseed oil). The coefficient at the water-lipid interface was on the order of 10-6 m/s. PRACTICAL APPLICATION: The Henry's constants (solubility) and transfer rate of oxygen to the lipid phase, fatty acids, fatty acid esters, and triacylglycerols (TAG) were measured. The lipids solubilized three to five times more oxygen than water, and mass transfer rate of oxygen at gas- and water-lipid interfaces were almost same. The constants for fatty acids and fatty acid esters were linearly correlated to their enthalpies of evaporation, and this correlation is expected to be useful for estimating the Henry's constants for other fatty acids and their esters.

A novel deodorization method of edible oil by using ethanol steam at low temperature.

A novel deodorization method of edible oil by using ethanol steam at low-temperature was developed. We compared the chemical changes in predeodorized rapeseed oil after anhydrous ethanol steam distillation at low temperature (140 to 220 °C) (L-ESD) and conventional high-temperature (250 °C) water-steam distillation (H-WSD) in terms of odor characteristics, physicochemical properties, micronutrient contents, antioxidant performance, and fatty acid composition. Compared with H-WSD (250 °C for 60 min), L-ESD at 180 °C for 80 to 100 min resulted in lower response values of electronic nose, free fatty acid (0.03% to 0.07%), and peroxide value (0.00 to 0.67 meq/kg), but higher retention of tocopherols (554.93 to 551.59 mg/kg), total phenols (43.36 to 45.42 mgGAE/kg), total carotenoids (65.78 to 67.85 mg/kg), phytosterols (585.80 to 596.53 mg/100 g), polyunsaturated fatty acids (27.95 to 28.01%), and better antioxidant properties. In conclusion, L-ESD can mitigate the damage of oil and thus significantly improve the safety of vegetable oils with a high retention of nutrients compared with conventional H-WSD. PRACTICAL APPLICATION: The present study aimed to compare the chemical changes in predeodorized rapeseed oil after anhydrous ethanol steam distillation at low temperature (140 to 220 °C) (L-ESD) and conventional high-temperature (250 °C) water-steam distillation (H-WSD) in terms of odor characteristics, physicochemical properties, micronutrient contents, antioxidant performance, and fatty acid composition. Results indicated that this finding supplies a theoretical basis for developing a method with retaining more micronutrients and producing less harmful substances for the deodorization of rapeseed oil.

Quantification of phenolic compounds in vegetable oils by mixed-mode solid-phase extraction isotope chemical labeling coupled with UHPLC-MS/MS.

In the present work, a rapid, accurate and cost-effective method has been developed for the simultaneous quantification of phenolic compounds in oil using mixed-mode solid-phase extraction (SPE) coupled with chemical labeling UHPLC-MS/MS. Mix-mode SPE weak cation cartridges were selected to enrich and purify phenolic compounds in oil, and hydroxyl moiety was dansylation as stable-isotope internal standard. The major parameters that affected the extraction and chemical labeling efficiency were investigated, and the method was fully validated. The limit of quantifications and the limit of detections were 0.002 µg kg-1 ~ 0.10 µg kg-1 and 0.006 µg kg-1 ~ 0.30 µg kg-1, respectively. The recoveries were 61.2% ~ 129.3% with intra-day and inter-day precision less than 12%. The results for 38 rapeseed oils revealed that 14 phenolic compounds, including canolol, phenolic acids, phenolic alcohols, tyrosol and vanillin from trace levels to relatively high content.

Critical kinetic parameters and rate constants representing lipid peroxidation as affected by temperature.

This study aimed to comparatively investigate the temperature effect on the kinetic parameters and rate constants representing lipid hydroperoxides (LOOH) formation and decomposition during initiation and propagation peroxidations. The initiation phase was characterized by induction period IP, overall initiation rate constant kIP, initiation oxidizability Oi, and the critical reverse micelle concentration of LOOH, CMCL. The propagation phase was characterized by its duration tp, the maximum rate of LOOH accumulation Rmax, maximum LOOH concentration [LOOH]max, propagation oxidizability Rn, composite rate constant kc, and LOOH decomposition rate constant kd. Oi and Rn indicated relatively high dependencies on temperature, respectively. Among the rate constants, kd better highlighted oxidizabilities as affected by temperature. The oxidizabilities had good correspondences with the Arrhenius kinetic (A and Ea) and Eyring thermodynamic (ΔS++ and ΔH++) parameters. The most endergonic reactions (ΔG++>0) were LOOH decompositions, followed by LOOH formations during the propagation and initiation phases, respectively.