Multifaceted analysis of the effects of roasting conditions on the flavor of fragrant Camellia oleifera Abel. seed oil.

Fragrant Camellia oleifera Abel. seed oil (FCSO), produced by a roasting process, is popular for its characteristic aroma. This study investigated the effects of various roasting temperatures (90℃, 120℃, 150℃, 180℃) and durations (20 min, 40 min, 60 min) on the flavor of FCSO by physicochemical properties, hazardous substances, sensory evaluation, and flavor analyses. The results showed that FCSO roasted at 120℃/20 min had a reasonable fatty acid composition with a lower acid value (0.16 mg/g), peroxide value (0.13 g/100 g), p-anisidine value (2.27), dibutyl phthalate content (0.04 mg/kg), and higher 1,1-diphenyl-2-picrylhydrazyl free radical scavenging activity (224.51 µmol TE/kg) than other samples. A multivariate analysis of FCSO flavor revealed that the 120℃/20 min group had a higher grassy flavor score (5.3 score) from nonanoic acid and a lower off-flavor score (2.2 score) from 2-methylbutyric acid. The principal component analysis showed that 120℃/20 min could guarantee the best flavor and quality of FCSO. Therefore, this information can guide the preparation of FCSO.

Effects of different amino acid enzymatic preparations on the quality and flavor of fragrant rapeseed oil.

Enzymatically prepared aromatic oils commonly have high purity and aroma quality. However, amino acid type and content vary greatly according to the type of oil, which impacts overall aroma and quality. In this study, the effects of lysine (Lys), arginine (Arg), proline (Pro), and glutamic (Glu) acid on physicochemical indices, nutrients, hazardous substances, fatty acid composition, and flavor during fragrant rapeseed oil (FRO) enzymatic preparation were investigated using the Maillard reaction (MR). In the lysine-treated group, the unsaturated fatty acids (93.16 %), α-tocopherol (183.06 mg/kg), γ-tocopherol (404.37 mg/kg), and δ-tocopherol (12.69 mg/kg) contents were the highest, whereas the acid value (1.27 mg/g) and moisture (0.10 %) and benzo[a]pyrene (1.45 µg/kg) contents were the lowest. Sensory evaluation showed that lysine effectively enhanced FRO flavor by enhancing the nutty/toasted flavor (4.80 scores). Principle component analysis (PCA) showed that the nutty/toasted flavor correlated mainly with 2,6-dimethylpyrazine, 2,5-dimethyl-pyrazine, 2-methyl-pyrazine, and trimethylpyrazine, nutty/toasted flavor strength increased with pyrazine content, which were the highest in the lysine group (24.02 µg/g). This study provides a guide for FRO preparation by adding external MR prerequisites.

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.

Effects of different oleogelators on the structural properties and composition of iron walnut-oil oleogels.

In this study, we compared the quality of iron walnut oil (IWO) oleogels prepared with different oleogelators, including γ-oryzanol/ß-sitosterol (OZ-PS), γ-oryzanol/triglyceride (OZ-TC), monoglycerides (MGS), beeswax (BW), beeswax-monoglycerides (BW-MGS), and carnauba wax (CW). The physicochemical and component properties, rheological and textural parameters, macroscopic morphologies, and antioxidant capacities of the resulting oleogels were analyzed. In addition, their microscopic properties were analyzed using Fourier-transform infrared (FTIR), X-ray powder diffraction (XRD) spectroscopy, and polarized light microscopy (PLM). The results showed that the gel structures produced by different oleogelators did not change the fatty acid composition of IWO. In addition, the IWO oleogel prepared with OZ-PS had a more stable network structure, excellent hardness at 4℃ (1116.51 g), better antioxidant capacity (766.50 µmol TE/kg) and higher total phenolic content (14.98 mg/kg) than any other experimental IWO oleogels. Moreover, comprehensive ranking by principal component analysis of numerous characteristics showed that the OZ-PS oleogel (2.533) ranked first among the six oleogels studied. Therefore, the IWO oleogel prepared with OZ-PS is a promising product, and our results provide guidance for the preparation of IWO oleogels, such as to increase their applications in the food industry.

High-oleic rapeseed oil quality indicators and endogenous antioxidant substances under different processing methods.

This study exposed high-oleic rapeseed oil (HORO) to different pretreatment (microwave or roasting) and processing methods to investigate (cold pressing, hexane extraction, subcritical butane extraction, and aqueous enzymatic extraction) the effects of processing technologies on HORO parameters associated with its physicochemical properties, endogenous antioxidant substances, and antioxidant capacity. The oil yield of various processing technologies was between 35.4% and 59.7%, and the fatty acid composition did not significantly differ. Hierarchical clustering and principal component analyses were used for evaluation. The results revealed that the microwave pretreatment-hexane extraction (M-HE) method resulted in significantly higher levels of tocopherols (688.4 mg/kg), polyphenols (1007.76 mg/kg), and phytosterols (1810.6 mg/kg) in HORO, implying strong free radical scavenging capacity (DPPH-oil: 79.63, DPPH-nonpolar: 71.42, DPPH-polar: 6.65, FRAP: 55.4, ABTS: 3043.7 µmol TE/kg). Hence, M-HE is a promising method for producing HORO with a higher stability and nutritional value.

Effects of Extraction Strategies on Yield, Physicochemical and Antioxidant Properties of Pumpkin Seed Oil.

This study investigated the effects of three extraction methods, including cold pressing (CP), microwave pretreatment pressing (MP), and supercritical fluid extraction (SFE), on the yield, physicochemical properties, bioactive compounds content, and antioxidant properties of pumpkin seed oil (PSO). Furthermore, the correlation between bioactive compounds and the antioxidant properties of PSO was determined. The results revealed that the yield of PSO extracted using the three methods was in the order of SFE > MP > CP. Additionally, the PSO generated by SFE showed the highest unsaturated fatty acid content, followed by MP and CP. Additionally, MP-PSO exhibited the highest acid value and saponification value, while SFE-PSO displayed the highest moisture content, peroxide value, and iodine value. Moreover, the PSO generated by MP demonstrated superior antioxidant properties compared to that of PSOs from CP and SFE in the oxidation induction, DPPH, FRAP, and ABTS tests. Finally, the correlation analysis revealed that specific types of bioactive compounds, such as ß-sitosterol and γ-tocopherol, were highly correlated with the antioxidant properties of PSOs. Consequently, this study provides comprehensive knowledge regarding PSO extraction, physicochemical properties, bioactive compound extraction, and the correlated antioxidant properties.

Selection of Salt-Tolerance and Ester-Producing Mutant Saccharomyces cerevisiae to Improve Flavour Formation of Soy Sauce during Co-Fermentation with Torulopsis globosa.

Soy sauce, as a traditional seasoning, is widely favoured by Chinese and other Asian people for its unique colour, smell, and taste. In this study, a salt-tolerance Saccharomyces cerevisiae strain HF-130 was obtained via three rounds of ARTP (Atmospheric and Room Temperature Plasma) mutagenesis and high-salt based screening. The ethanol production of mutant HF-130 was increased by 98.8% in very high gravity fermentation. Furthermore, ATF1 gene was overexpressed in strain HF-130, generating ester-producing strain HF-130-ATF1. The ethyl acetate concentration of strain HF-130-ATF1 was increased by 130% compared to the strain HF-130. Finally, the soy sauce fermentation performance of Torulopsis globosa and HF-130-ATF1 was compared with T. globosa, HF-130, HF-130-ATF1, and Torulopsis and HF-130. Results showed ethyl acetate and isoamyl acetate concentrations in co-fermentation of T. globosa and HF-130-ATF1 were increased by 2.8-fold and 3.3-fold, respectively. In addition, the concentrations of ethyl propionate, ethyl caprylate, phenylethyl acetate, ethyl caprate, isobutyl acetate, isoamyl alcohol, phenylethyl alcohol, and phenylacetaldehyde were also improved. Notably, other three important flavour components, trimethylsilyl decyl ester, 2-methylbutanol, and octanoic acid were also detected in the co-fermentation of T. globosa and HF-130-ATF1, but not detected in the control strain T. globosa. This work is of great significance for improving the traditional soy sauce fermentation mode, and thus improving the flavour formation of soy sauce.

Optimization of Composite Decolorizer Efficacy Based on Decolorization Efficiency, Toxicity, and Nutritional Value of Rice Bran Oil.

This study compared the effect of five different adsorbents (activated clay, activated carbon, attapulgite clay, bentonite, diatomite) on the levels of nutrients, harmful substance retention, and decolorization in rice bran oil. Among the adsorbents tested, activated carbon displayed the highest decolorization efficiency (82.90%) and adsorption effect on 3,4-benzopyrene (BaP, 89.53%) and 3-monochloropropane-1,2-diol ester (41.55%), whereas activated clay had the highest oryzanol retention percentages (85.98%) and affordability. Activated carbon and activated clay were therefore selected as composite decolorizing agents. Based on single-factor and Box-Behnken response surface tests, the optimal conditions for decolorization efficiency (97.08%), oryzanol retention (89.62%), sterol retention (90.16%), vitamin E retention (79.91%), and benzo(a)pyrene adsorption percentages (95.98%) were determined to be achieved by using a 5% (w/w) composite decolorant (activated clay:activated carbon=5:1), at a temperature of 116℃, with an incubation time of 33 min. This study provides evidence to support the efficacy of compound decolorants, which may have practical use in large-scale industrial applications of edible oil decolorization during refinement.

Resonance and bifurcation of fractional quintic Mathieu-Duffing system.

In this paper, the main subharmonic resonance of the Mathieu-Duffing system with a quintic oscillator under simple harmonic excitation, the route to chaos, and the bifurcation of the system under the influence of different parameters is studied. The amplitude-frequency and phase-frequency response equations of the main resonance of the system are determined by the harmonic balance method. The amplitude-frequency and phase-frequency response equations of the steady solution to the system under the combined action of parametric excitation and forced excitation are obtained by using the average method, and the stability conditions of the steady solution are obtained based on Lyapunov's first method. The necessary conditions for heteroclinic orbit cross section intersection and chaos of the system are given by the Melnikov method. Based on the separation of fast and slow variables, the bifurcation phenomena of the system under different conditions are obtained. The amplitude-frequency characteristics of the total response of the system under different excitation frequencies are investigated by analytical and numerical methods, respectively, which shows that the two methods achieve consistency in the trend. The influence of fractional order and fractional derivative term coefficient on the amplitude-frequency response of the main resonance of the system is analyzed. The effects of nonlinear stiffness coefficient, parametric excitation term coefficient, and fractional order on the amplitude-frequency response of subharmonic resonance are discussed. Through analysis, it is found that the existence of parametric excitation will cause the subharmonic resonance of the Mathieu-Duffing oscillator to jump. Finally, the subcritical and supercritical fork bifurcations of the system caused by different parameter changes are studied. Through analysis, it is known that the parametric excitation coefficient causes subcritical fork bifurcations and fractional order causes supercritical fork bifurcations.

Assessment of the Physicochemical Properties of Fragrant Rapeseed Blended Hotpot Oil by Principal Component Analysis.

In this study, a nutritious, healthy Chongqing hotpot oil with excellent flavor was blended while considering nutrition, flavor, and health aspects. Four blended hotpot oils prepared from fragrant rapeseed, palm, sesame, and chicken oils were analyzed to determine their physicochemical properties, antioxidant capacities, levels of harmful substances, and nutritional compositions, and their sensory qualities were evaluated. Principal component analysis was performed to identify the best hotpot oil (10% chicken oil + 20% palm oil + 10% sesame oil + 60% fragrant rapeseed oil), which exhibited good antioxidant capacity (Oxidation Stability Index: 7.95 h; 2,2-diphenyl-1-picrylhydrazyl: 168.6 µmol/kg, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate): 116.7 µmol/kg, and ferric-reducing/antioxidant power: 63.9 µmol/kg), a high sensory score (7.7/10), stable physicochemical properties (acid value: 0.27 mg/g and peroxide value: 0.01 g/100 g), and high tocopherol (54.22%), and phytosterol retention (98.52%) after boiling for 8 h. Although the 3,4-benzopyrene content of this hotpot oil exceeded the EU standard after boiling for 7 h, the increase in the amount of harmful substances was the lowest.

Changes in the physicochemical properties and antioxidant capacity of Sichuan hotpot oil.

This study aimed to develop nutritious and healthy Sichuan hotpot oil. Four blended oil formulas were formulated using MATLAB based on the fatty acid composition of four base constituents (beef tallow, mutton tallow, peanut oil, and palm oil). The sensory characteristics, physicochemical properties, nutritional composition, harmful substances, and antioxidant capacity of the oils were analyzed during the boiling process. A blend of 60% beef tallow + 10% mutton tallow + 10% peanut oil + 20% palm oil exhibited a low level of peroxide (0.03 g/100 g) and malondialdehyde (0.04 mg/kg), and high phytosterol content (1028.33 mg/kg), which was the suitable hotpot blending oil. Furthermore, the changes in the physicochemical properties during boring were low, with a high retention rate of phytosterol (94.85%), and the levels of 3,4-benzopyrene (1.12 µg/kg) and 3-monochloropropane-1,2-diol ester (0.67 mg/kg) were both lower than the recommended limits. This study will provide a theoretical basis for the advancement of the hotpot oil industry.

Physicochemical properties of rice bran blended oil in deep frying by principal component analysis.

This study aimed to obtain a rice bran blended oil with good quality in deep frying. The thermal stability, nutrients and harmful substances of rice bran oil (RBO) and other four oils (palm oil, PO; cottonseed oil, CO; sunflower oil, SuO; soybean oil, SO) were analyzed. Besides, the blended oil formulas were established by the principal component analysis method, and their physicochemical properties, frying characteristic indicators, nutrients, and harmful substances were compared. The results provided that two suitable blended oil formulas (F1: 50% RBO + 40% PO + 10% CO; F2: 60% RBO + 35% PO + 5% CO) of good frying performance were attained by principal component analysis. The acid value (1.19 mg/g), peroxide value (0.09 meq/kg), residual oil rate (8.07%), 3-MCPD ester reduction content (2.33 mg/kg), benzopyrene concentration content (0.95 µg/kg) and vitamin E consumption rate (67.86%) in F2 were lower than that in F1. Moreover, the oryzanol retention rate (87.84%) of F2 was higher than that of F1. In summary, F2 was more conducive to human health and more suitable than F1 in deep-frying. This information had an important directive on the industrial production of rice bran blend oil. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-022-05472-7.

Comparison of Different Extraction Processes on the Physicochemical Properties, Nutritional Components and Antioxidant Ability of Xanthoceras sorbifolia Bunge Kernel Oil.

In this study, we investigated and compared the oil yield, physicochemical properties, fatty acid composition, nutrient content, and antioxidant ability of Xanthoceras sorbifolia Bunge (X. sorbifolia) kernel oils obtained by cold-pressing (CP), hexane extraction (HE), aqueous enzymatic extraction (AEE), and supercritical fluid extraction (SFE). The results indicated that X. sorbifolia oil contained a high percentage of monounsaturated fatty acids (49.31-50.38%), especially oleic acid (30.73-30.98%) and nervonic acid (2.73-3.09%) and that the extraction methods had little effect on the composition and content of fatty acids. X. sorbifolia oil is an excellent source of nervonic acid. Additionally, the HE method resulted in the highest oil yield (98.04%), oxidation stability index (9.20 h), tocopherol content (530.15 mg/kg) and sterol content (2104.07 mg/kg). The DPPH scavenging activity rates of the oil produced by SFE was the highest. Considering the health and nutritional value of oils, HE is a promising method for X. sorbifolia oil processing. According to multiple linear regression analysis, the antioxidant capacity of the oil was negatively correlated with sterol and stearic acid content and positively correlated with linoleic acid, arachidic acid and polyunsaturated fatty acid content. This information is important for improving the nutritional value and industrial production of X. sorbifolia.

Characteristics and Antioxidant Activity of Walnut Oil Using Various Pretreatment and Processing Technologies.

This study was the first time the effects of pretreatment technology (microwave roasting, MR; oven roasting, OR; steaming roasting, SR) and processing technology (screw pressing, SP; aqueous enzymatic extraction, AEE; subcritical butane extraction, SBE) on the quality (physicochemical properties, phytochemical content, and antioxidant ability) of walnut oil were systematically compared. The results showed that the roasting pretreatment would reduce the lipid yield of walnut oil and SBE (59.53−61.19%) was the processing method with the highest yield. SR-AEE oil provided higher acid value (2.49 mg/g) and peroxide value (4.16 mmol/kg), while MR-SP oil had the highest content of polyunsaturated fatty acid (73.69%), total tocopherol (419.85 mg/kg) and total phenolic compounds (TPC, 13.12 mg/kg). The DPPH-polar and ABTS free radicals' scavenging abilities were accorded with SBE > AEE > SP. SBE is the recommended process for improving the extraction yield and antioxidant ability of walnut oil. Hierarchical cluster analysis showed that processing technology had a greater impact on walnut oil than pretreatment technology. In addition, multiple linear regression revealed C18:0, δ-tocopherol and TPC had positive effects on the antioxidant ability of walnut oil, while C18:1n-9, C18:3n-3 and γ-tocopherol were negatively correlated with antioxidant activity. Thus, this a promising implication for walnut oil production.

Effects of Structural and Compositional Changes of Nanochloropsis oceania after Enzyme Treatment on EPA-Rich Lipids Extraction.

Improved methods for the extraction of eicosapentaenoic acid (EPA), an essential and economically important polyunsaturated fatty acid, are urgently required. However, lipid extraction rates using food-grade solvents such as ethanol are usually low. To improve the ethanol-based extraction rate, and to elucidate the relevant mechanisms, we used cellulase and laccase to treat powdered Nannochloropsis, one of the most promising microalgal sources of EPA. Cellulase and laccase synergistically increased lipid yields by 69.31% and lipid EPA content by 42.63%, by degrading the amorphous hemicellulose and cellulose, improving crystallinity, and promoting the release and extraction of lysodiacylglyceryltrimethylhomoserine. Scanning electron microscopy showed that cell morphology was substantially altered, with cell-wall rupture, loss of cell boundaries, and the release of intracellular substances. In conclusion, Nannochloropsis lipid yields may be directly linked to cell-wall hemicellulose structure, and enzymatic treatment to alter this may improve lipid yields.

Effects of roasting and deodorisation on 3-monochloropropane-1, 2-diol esters, 3, 4-benzopyrene and trans fatty acids in peanut oil.

Hazardous substances are readily produced during roasting and deodorisation in the preparation of peanut oil. The aim of this work was to investigate the variation of 3-monochloropropane-1, 2-diol ester (3-MCPDE), 3, 4-benzopyrene (BaP) and trans fatty acid (TFA) contents in the roasting and deodorisation segments of peanut oil production process. Roasting temperatures and durations significantly affected the contaminants contents in peanut oil; they increased significantly at a roasting temperature >210°C and time >60 min. In the deodorisation segment, the BaP and TFA contents were over the standard limits at a deodorisation temperature >210°C and time >140 min. Analysis showed that 3-MCPDE was significantly correlated with the formation of C18:2T (r = 0.979) and there was a linear relationship between BaP and C18:1T (Y = 0.509 C18:1T). This information will provide guidance for the precise and appropriate processing of peanut oil.

Antibody semorinemab reduces tau pathology in a transgenic mouse model and engages tau in patients with Alzheimer's disease.

Tau has become an attractive alternative target for passive immunotherapy efforts for Alzheimer's disease (AD). The anatomical distribution and extent of tau pathology correlate with disease course and severity better than other disease markers to date. We describe here the generation, preclinical characterization, and phase 1 clinical characterization of semorinemab, a humanized anti-tau monoclonal antibody with an immunoglobulin G4 (igG4) isotype backbone. Semorinemab binds all six human tau isoforms and protects neurons against tau oligomer neurotoxicity in cocultures of neurons and microglia. In addition, when administered intraperitoneally once weekly for 13 weeks, murine versions of semorinemab reduced the accumulation of tau pathology in a transgenic mouse model of tauopathy, independent of antibody effector function status. Semorinemab also showed clear evidence of target engagement in vivo, with increases in systemic tau concentrations observed in tau transgenic mice, nonhuman primates, and humans. Higher concentrations of systemic tau were observed after dosing in AD participants compared to healthy control participants. No concerning safety signals were observed in the phase 1 clinical trial at single doses up to 16,800 mg and multiple doses totaling 33,600 mg in a month.

Comparative Analysis of Rapeseed Oils Prepared by Three Different Methods.

Flavoured rapeseed oils prepared using traditional technologies (oils A and B) and a fragrant rapeseed oil obtained using an enzymatic Maillard reaction (oil C) were analysed to show that oil C featured basic indicators and a fatty acid composition similar to those of traditional oils while exhibiting a higher comprehensive sensory evaluation score. Volatile component, odour activity value (OAV), and relative odour activity value (ROAV) analyses revealed that oil C had an elevated content of pyrazines (20.83%) and aldehydes (38.15%), which resulted in stronger charred and caramel flavours. The aroma of oil C was directly impacted by 3-methylbutyraldehyde (OAV > 1) and was modified by 3-methylthiopropionaldehyde and nonanal (RAOV > 1 in both cases). Thus, the developed technology was found to be well suited for the production of novel and safe fragrant rapeseed oil.

Evaluation of Chemical Properties of Commercial Extra Virgin Olive Oil in China.

The aim of the study was to investigate the chemical properties of the most popular commercial extra virgin olive oils (EVOOs) in China. A total of 14 EVOO samples were collected and evaluated, and significant differences were observed with respect to physicochemical properties, fatty acid composition, minor components, and the oxidation stability index (OSI). The results showed that the chemical properties of EVOOs were significantly affected by different producing areas. The oleic acid (C18:1) content (average value: 77.80%), squalene content (average value: 6052.28 mg/kg), and OSI (average value: 9.90 h) of the Spanish olive oil were higher than those of the other oils investigated, while the total phenolic content (average value: 308.34 mg/kg) was the lowest. Greek EVOOs had the lowest total sterol content (average value: 1023.48 mg/kg) and OSI (average value: 4.22 h). The C18:1 content (66.42%) and squalene content (3173.42 mg/kg) of the EVOO from China were lower than those of the other oils, while the palmitic acid (C16:0, 16.82%), linoleic acid (C18:2, 12.18%), total phenolic (553.17 mg/kg), and total sterol content (1904.77 mg/kg) were higher than those of the other olive oils. The EVOOs of the various countries could be distinguished by hierarchical cluster analysis (HCA). In addition, multiple linear regression (MLR) analyses between the OSI and chemical properties revealed that squalene (R = 0.729) and the unsaturation determined by the specific UV adsorption at 232 nm (K232, R = -0.300) were the main factors to affecting the EVOO oxidation stability.