Characterization of the Aroma Profile of Ginger Powder Produced by a Split-Stream Spray-Drying Process.

Freeze-dried ginger (Zingiber officinale) is renowned for its high quality, but it is expensive. As an alternative, spray drying can be explored for producing ginger powder. However, sugar rich feed solutions can lead to stickiness development during the process. Adding carrier materials increases costs and labeling. Accordingly, a split-stream spray-drying process was developed, where ginger fibers in their natural composition were reintroduced as a carrier material into the spray-drying process. The inlet and outlet temperatures were set at 220 and 80 °C, respectively, for optimal aroma retention. Using a stir bar sorptive extraction-gas chromatography-mass spectrometry-olfactometry, the results revealed that reintegrating ginger fibers significantly increased the concentration of eight key odorants. Although freeze-dried ginger retains more aroma, the total concentration of twenty-seven odorants in the developed spray-dried ginger was 1.9 times higher compared to frozen ginger.

Effects of Silica Hydrogel on Degumming of Fragrant Rapeseed Oil.

Hot-pressed rapeseed oils with pleasant flavor, i.e., fragrant rapeseed oils, are favored by consumers, especially people from the southwest provinces of China. Although degumming is an important section in producing edible rapeseed oils, conventional degumming techniques are generally suffered from disadvantages such as moisture control, and large losses of micronutrients and flavors. In the present paper, hot-pressed rapeseed oils were treated with silica hydrogel to remove their gums, and changes in phospholipids, acid values, peroxide values, tocopherols, total phenols, and flavor compounds were analyzed to compare the silica hydrogel-degumming with conventional methods. The optimized conditions were suggested to be carried out at 45°C for 15 min, and the silica hydrogel dosage was 1.10%. More than 97.00% of phospholipids were removed after the degumming, and more than 85.00% of micronutrients, were retained in the treated oils. The degumming efficiency was therefore significantly higher than those operated by conventional acid degumming and soft degumming techniques. It was found that the dosage of the silica hydrogel significantly affected the removal rate of phospholipids compared with degumming time and temperature. There were nearly typical volatile compounds found in the rapeseed oils, while most of them kept almost stable after the silica hydrogel-degumming. In this regard, silica hydrogel adsorption exhibited little effect on volatile compounds, making it more suitable for the production of fragrant rapeseed oils.

A comparative study on flavor trapping techniques from the viewpoint of odorants of hot-pressed rapeseed oil.

Rapeseed oil, as one of the three major vegetable oils in the world, its matrix effect makes the decoding flavor a challenge. Solid-phase microextraction (SPME), SPME-Arrow, headspace stir bar sorptive extraction (HSSE), direct thermal desorption (DTD), and solvent-assisted flavor evaporation (SAFE) were compared based on the odorants in hot-pressed rapeseed oil. Besides, methodological validation for 31 aroma standards was conducted to compare reliability and robustness of these approaches. DTD showed the largest proportion of acids, while the other techniques extracted a majority of nitriles. The highest number of odorants was detected by SAFE (31), followed by HSSE (30), SPME-Arrow (30), SPME (24), and DTD (14). SPME-Arrow showed the best performance in linearity, recovery, and reproducibility followed by SPME, HSSE, DTD, and SAFE. Results reveal the advantages and limitations of diverse methodologies and provide valuable insights for the selection of extraction methods in an oil matrix and flavor decoding.

Upcycling of Soy Whey with Ischnoderma benzoinum toward Production of Bioflavors and Mycoprotein.

Soy whey is becoming a worldwide issue as a liquid waste stream that is often discarded after tofu, soy protein, and soy-based dairy alternative manufacturing. This study established a model to produce a bioflavor and mycoprotein using fermentation of soy whey by a basidiomycete Ischnoderma benzoinum. Under the dedicated control of a fermentation system, an intense almond-like and sweetish aroma was perceived by a trained sensory panel (n = 10) after fermentation of pure soy whey within 20 h. By application of direct immersion-stir bar sorptive extraction combined with gas chromatography-mass spectrometry-olfactometry (DI-SBSE-GC-MS-O), around 1.0 mg/L benzaldehyde and 1.1 mg/L 4-methoxybenzaldehyde imparting a pleasant almond-like odor note were determined in the fermented soy whey with I. benzoinum. Concurrently, a certain of amount of the dry mass of I. benzoinum was accumulated with 73.2 mg/g crude protein and seven essential amino acids.

Influence of peeling on volatile and non-volatile compounds responsible for aroma, sensory, and nutrition in ginger (Zingiber officinale).

Industrial use of ginger after peeling results in large amounts of agro-waste. To provide a basic reference for the sustainable processing of ginger products as a spice, we investigated the differences between unpeeled ginger, peeled ginger, and corresponding ginger peel, in terms of aroma, sensory profiles, and nutrition relevant physicochemical properties. The results showed that the total concentrations of identified odor-active compounds in unpeeled ginger, peeled ginger, and ginger peel were 876.56, 672.73, and 105.39 mg/kg, respectively. Unpeeled ginger exhibited more intense citrus-like and fresh impressions compared to peeled ginger, revealed by descriptive sensory analyses. This is relevant to the high odor activity values of odorants such as ß-myrcene (pungent, citrus-like), geranial (citrus-like), citronellal (citrus-like, sourish), and linalool (floral, fresh). In parallel, unpeeled ginger contained higher total polyphenol (84.49 mg/100 g) and total sugar content (33.4 g/kg) in comparison with peeled ginger (76.53 mg/100 g and 28.6 g/kg).

Comparative characterization of key odorants and aroma profiles of fragrant rapeseed oil under different roasting conditions.

Fragrant rapeseed oil (FRO) produced by typical roasting process is popular for its characteristic aroma. Accordingly, key aroma-active compounds were characterized in FRO by the Sensomics approach and then correlated to the crucial roasting parameters revealed by aroma profile analysis and hierarchical cluster analysis. Nineteen key odorants in FRO were identified and quantified, among which dimethyl trisulfide (OAV, odor active value, 323, cabbage-like, sulfury) and 4-isothiocyanato-1-butene (OAV, 88, pungent) were the most important aroma-active compounds in FRO and showed first rising and then decline trends as the increased roasting temperature and time. The oil under high-temperature-short time and low-temperature-long time conditions imparted similar aroma profiles. On the basis of sensory evaluation, roasting at 160, 170, 180, 190, and 200 °C should not exceed 50, 40, 30, 30, and 30 min, respectively to satisfy consumer preference. All findings provide a reference on industrial FRO production in terms of not only aroma but also sustainability.

Characterization of Thermally Induced Flavor Compounds from the Glucosinolate Progoitrin in Different Matrices via GC-TOF-MS.

As important flavor precursors, glucosinolates are ubiquitous in the plant family of Brassicaceae. Glucosinolate degradation products are the major volatile flavor compounds of rapeseed oil, accounting for up to 80% of the total volatiles. However, up to now, little attention has been paid to the volatile flavor products of the nonenzymatic thermal degradation of glucosinolates. One of the most important factors that determine the flavor of hot-pressed rapeseed oil is the roasting process, where the thermal degradation of glucosinolates mainly occurs. The thermal degradation behavior and volatile products of progoitrin (the main glucosinolate of rapeseed) in different matrices (phosphate buffer at a pH value of 5.0, 7.0, or 9.0, sea sand, and rapeseed powder) at different temperatures (150-200 °C) and times (0-60 min) were studied using HPLC and GC-TOF-MS. Thereby, the degradation rate of progoitrin decreased in the following order: pH 9.0 > sea sand > rapeseed powder > pH 7.0 > pH 5.0. Further, a higher degradation was observed with increasing temperature and time. Under the applied conditions in this study, 2,4-pentadienenitrile was the major nitrile and thiophenes were the major sulfur-containing volatile compounds formed. Possible formation pathways of main sulfur-containing and nitrogen-containing volatiles were proposed.

Comparative analysis of aroma compounds in French fries and palm oil at three crucial stages by GC/MS-olfactometry, odor activity values, and aroma recombination.

BACKGROUND: Flavor is a key element affecting the popularity of French fries (FFs). When oil is heated, the changes in oil quality can affect the flavor of the food directly. RESULTS: The flavor of FFs showed three crucial stages: the break-in (3.0% to 6.8% of total polar compounds (TPC)), optimum (7.0% to 19% of TPC), and degrading (above 19.5% of TPC) stages. To distinguish the key aroma compounds in the three stages, the FFs, prepared in palm oil (PO) at TPC of 3.0% (FF3), 7.5% (FF8), 19.5% (FF20), and their relevant oils (PO3, PO8, PO20), were selected for molecular sensory science analysis. The results indicated that the concentration of (E, E)-2,4-decadienal linked with the deep-fried odor was low in FF3, which led to a lower sensory score in the FF3 sample. The FF8 sample had a high (E, E)-2,4-decadienal content and received a high sensory score. The FF20 sample possessed high hexanoic acid, heptanoic acid (sweaty odor), benzaldehyde (stale odor), octanoic acid (sweaty odor), (E)-2-undecenal (fatty odor), and trans-4,5-epoxy-(E)-2-decenal (metallic odor) content, thus leading to FFs having an undesirable flavor and PO20 showed high hexanoic acid and heptanoic acid content, contributing to a lower sensory score in PO20. CONCLUSION: The FFs' flavor became undesirable when TPC was above 19.5% due to significant influences of some off-flavor compounds. It is therefore essential to prevent the generation of rancid substances to prolong the optimum stage during frying. © 2021 Society of Chemical Industry.

Flavor of rapeseed oil: An overview of odorants, analytical techniques, and impact of treatment.

As one of the three major vegetable oils in the world, rapeseed oil is appreciated for its high nutritional value and characteristic flavor. Flavor is an essential attribute, determining rapeseed oil quality and consumer acceptance. The present manuscript provides a systematic literature review of recent advances and knowledge on the flavor of rapeseed oil, which focuses on aroma-active as well as off-flavor compounds, flavor analysis techniques (i.e., extraction, qualitative, quantitative, sensory, and chemometric methods), and effects of treatments (storage, dehulling, roasting, microwave, flavoring with herbs, refining, and oil heating) on flavor from sensory and molecular perspectives. One hundred thirty-seven odorants found in rapeseed oil from literature are listed and possible formation pathways of some key aroma-active compounds are also proposed. Future flavor analysis techniques will evolve toward time-saving, portability, real-time monitoring, and visualization, which aims to obtain a "complete" flavor profile of rapeseed oil. The changes of volatile compounds in rapeseed oil under different treatments are summarized in this view. Studies to elucidate the influence of different treatments on the formation of aroma-active compounds are needed to get a deeper understanding of factors leading to the variations of rapeseed oil flavor.

A chemometrics approach comparing characteristics and free radical scavenging capacity of flax (Linum usitatissimum L.) oils obtained from seeds and cakes with different extraction methods.

BACKGROUND: Flax oil, a nutritive vegetable oil, is a rich natural source of the essential C18:3 α-linolenic acid and trace nutrients (tocopherol, phytosterol, polyphenol, flavonoid, etc.). In most small- and medium-sized facilities, the oil content in pressed cake is as high as 10%, which is not fully extracted and utilized. These cannot be neglected since they account for a considerable proportion. Characteristics and free radical scavenging capacity of flax (Linum usitatissimum L.) oil obtained from seeds and cakes with different extraction methods - cold-pressing, hot-pressing (120 and 160 °C) and solvent extraction (oil extracted with solvent from flaxseed, cold-pressed cake, and hot-pressed cake) - were evaluated and analyzed using chemometrics methods. RESULTS: The composition of C18:3 α-linolenic acid of flax oil was not affected by the extraction methods in this work. Flax oils extracted with solvent from pressed cakes had lower content of bioactive minor components (tocopherols and phytosterols) compared with pressed and solvent-extracted seed oils. The former also showed poorer oxidative stability and free radical scavenging capacity (polar fraction) when compared with the latter. Flax oils could be distinguished with principal component analysis and hierarchical cluster analysis. Tocopherols and phytosterols exhibited significant contributions to the antioxidant capacity of flax oils via correlation analysis and multiple linear regression analysis. CONCLUSION: Tocopherols and phytosterols were appropriate and potent indicators for evaluating the antioxidant capacity of flax oil. Results have important implications for the industrial production and nutritional value of flax oil, especially for flax oils from the cakes after pressing. © 2021 Society of Chemical Industry.

Sinterability and Dielectric Properties of LiTaO3-Based Ceramics with Addition of CoO.

Lithium tantalite (LiTaO3) is a common piezoelectric and ferroelectric crystal, but the LiTaO3 polycrystalline ceramics have rarely been reported, and their refractory character presents difficulties in their fabrication. In this study, LiTaO3-based ceramics with different amounts of CoO were prepared by pressureless sintering at 1250 °C, and the effects of the amount of sintering aid on the sinterability, microstructure, and dielectric properties of the ceramics were investigated. The relative densities of the LiTaO3-based ceramics were significantly improved by the addition of CoO powder. The LiTaO3-based ceramics achieved the highest relative density (89.4%) and obtained a well-grained microstructure when the added amount of CoO was 5 wt.%. Only the LiTaO3 phase in the ceramics was observed, indicating that the ions Co diffused into the LiTaO3 lattices and mainly existed in two forms: Co2+ and Co3+. The effects of the added amount of CoO on the dielectric properties of the LiTaO3-based ceramics were studied thoroughly. Consequently, the dielectric constant was enhanced, and the dielectric loss decreased in the LiTaO3-based ceramics with the addition of CoO. The optimal value was obtained at 5 wt.% of CoO-added LiTaO3-based ceramics.

Physicochemical properties and health risk assessment of polycyclic aromatic hydrocarbons of fragrant rapeseed oils in China.

BACKGROUND: Fragrant rapeseed oil is a type of hot-pressed oil in China. In this study, physicochemical properties, oxidative stability index (OSI), tocopherols, sterols, and polycyclic aromatic hydrocarbons (PAHs) in fragrant rapeseed oils were evaluated. Additionally, the cancer risk assessment pertaining to PAHs in fragrant rapeseed oil was investigated. RESULTS: Acid values (0.64-2.68 mg potassium hydroxide per gram), peroxide values (1.58-4.86 mmol kg-1 ), and color values (R = 2.6-5.8, Y = 35) of fragrant rapeseed oils were all within codex limits. Tocopherols and sterols ranged from 559.5 to 783.7 mg kg-1 and 4412.6 to 7859.8 mg kg-1 respectively. The OSI (110 °C) was between 4.8 and 15.9 h, with an average value of 10.8 h. Mean values of benzo[a]pyrene and PAH4 (chrysene, benz[a]anthracene, benzo[b]fluroranthene, and benzo[a]pyrene) were 2.32 µg kg-1 and 8.21 µg kg-1 respectively. The 95% dietary exposure of benzo[a]pyrene equivalent (BaPeq) contents from PAH4 were 0.3474 ng kg-1 day-1 , 0.3942 ng kg-1 day-1 , 1.8293 ng kg-1 day-1 , and 0.4294 ng kg-1 day-1 for male children, adolescents, adults, and seniors respectively. For females, these values were 0.3443 ng kg-1 day-1 , 0.3228 ng kg-1 day-1 , 1.8697 ng kg-1 day-1 , and 0.4084 ng kg-1 day-1 , respectively. Moreover, incremental lifetime cancer risk values at the cumulative probabilities of 91.3% and 91.6% for male adults and female adults respectively were higher than 1 × 10-5 . CONCLUSION: The results imply that the potential risk of cancer with PAHs in fragrant rapeseed oil should be a concern, especially for the health of adults. Fragrant rapeseed oil is still a product subject to contamination by PAHs. Limits for PAH4 of fragrant rapeseed oil should be included in Chinese regulations to improve safety. © 2020 Society of Chemical Industry.

Improving UV Resistance of Aramid Fibers by Simultaneously Synthesizing TiO2 on Their Surfaces and in the Interfaces Between Fibrils/Microfibrils Using Supercritical Carbon Dioxide.

Aramid fibers with low density and high strength, modulus, and thermal resistance are widely used in applications such as bulletproof vests and cables. However, owing to their chemical structure, they are sensitive to ultraviolet light, which degrades the fibers' useful mechanical properties. In this study, titanium dioxide (TiO2) nanoparticles were synthesized both on the aramid III fiber surface and in the interfacial space between the fibrils/microfibrils in supercritical carbon dioxide (scCO2) to improve the UV resistance of aramid fibers. The effects of scCO2 treatment pressure on the TiO2 structure, morphology, surface composition, thermal stability, photostability, and mechanical properties were investigated using Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetric analysis, ultraviolet-visible spectroscopy, and single-fiber test. The results show that amorphous TiO2 formed on the fiber surface and the interface between fibrils/microfibrils, and decreased the photodegradation rate of the aramid III fiber. Moreover, this modification can also improve the tensile strength via treatment at low temperature and without the use of a solvent. The simple synthesis process in scCO2, which is scalable, is used for mild modifications with a green solvent, providing a promising technique for synthesizing metal dioxide on polymers.

Calculation of Volume Fractions of In Situ TiB and Residual Stress Distributions in Functionally Graded Composite of Ti-TiB-TiB2.

Ti matrix composite with a polylaminate structure was successfully fabricated via spark plasma sintering (SPS) process. A temperature gradient field (TGF) was obtained during the sintering to form functionally graded material (FGM) in a vacuum under 40 MPa for 5 min. The actual volume fractions of TiB in the matrix were calculated based on the X-ray diffraction pattern. The target volume fractions of TiB were 0%, 20%, 40%, 60%, 80% and 100%. The calculated TiB volume fractions were slightly higher than the target volume fractions in layers 2-4 and lower than the target volume fractions in layers 5-6 and the deviations in layers 4 and 5 were less than 5% of the target volume. Based on the elastic axial symmetry model, the residual stress distributions in the Ti matrix composite with a polylaminate structure were simulated, indicating a relatively low thermal residual stress in the FGM.

Effects of SiO2 content on the nanomechanical properties of CoCrPt-SiO2 granular films.

CoCrPt material is used for perpendicular magnetic recording media due to its high magneto-crystalline anisotropy that brings good thermal stability on the media. The addition of SiO2 between the CoCrPt grains offers benefits including lower noise and better thermal stability. It has been reported that the SiO2 content has strong effects on the media's recording performance such as coercivity, anisotropy and noise. In this work, we focus on studying the effects of the SiO2 content on the nanomechanical properties of the media which are critical for the head-disk interface reliability. Variations of these properties with SiO2 content provide guidelines for optimum designs considering both recording and mechanical interface performance.

A microelectromechanical systems (MEMS) force-displacement transducer for sub-5 nm nanoindentation and adhesion measurements.

We present a highly sensitive force-displacement transducer capable of performing ultra-shallow nanoindentation and adhesion measurements. The transducer utilizes electrostatic actuation and capacitive sensing combined with microelectromechanical fabrication technologies. Air indentation experiments report a root-mean-square (RMS) force resolution of 1.8 nN and an RMS displacement resolution of 0.019 nm. Nanoindentation experiments on a standard fused quartz sample report a practical RMS force resolution of 5 nN and an RMS displacement resolution of 0.05 nm at sub-10 nm indentation depths, indicating that the system has a very low system noise for indentation experiments. The high sensitivity and low noise enables the transducer to obtain high-resolution nanoindentation data at sub-5 nm contact depths. The sensitive force transducer is used to successfully perform nanoindentation measurements on a 14 nm thin film. Adhesion measurements were also performed, clearly capturing the pull-on and pull-off forces during approach and separation of two contacting surfaces.

Assessment of contamination source and quality control approach for polycyclic aromatic hydrocarbons in wood-pressed rapeseed oil.

Contamination sources of polycyclic aromatic hydrocarbons (PAHs) in the raw material, oil production and storage processes of wood-pressed rapeseed oil were investigated in this study. The results showed that benzo[a]pyrene (BaP) and PAH4 (sum of BaP, benzo[a]fluoranthene, benzo[b]fluoranthene and chrysene) were unevenly distributed in the kernel (0.56-0.98 and 2.84-8.64 µg/kg, respectively) and hull (1.53-3.17 and 13.49-22.31 µg/kg, respectively) of the rapeseed raw materials. The contents of BaP and PAH4 continuously increased during the process of wood-pressed rapeseed oil, ranging from 2.21 to 10.93 and 9.36 to 40.03 µg/kg, thus demonstrating that a wide range of pollution sources of PAHs existed for the test wood-pressed rapeseed oils. The initial temperature and time of roasting should be controlled at <210°C and <60 min, due to the generation of PAHs in rapeseed by over-roasting. In addition, contact tools and substance such as lubricating oil (from the mill), heat-transfer oil (from roasting machine), rubber gaskets and straws should be properly screened. The BaP and PAH4 of rapeseed placed in the roasting area increased from 0.5 to 2.24 and from 2.08 to 9.03 µg/kg, respectively. Therefore, roasting fume control and treatment systems are necessary and the roasting section should be strictly isolated from the other stages. Storage can slightly lower the PAHs amounts in the rapeseed oil, which made the contents of BaP and PAH4 decrease from 27.00 to 24.70 and from 138.63 to 117.58 µg/kg, respectively. Quality control measures of PAHs in wood-pressed rapeseed oil were proposed and implemented, and the final oil products' BaP and PAH4 were kept below 2 and 10 µg/kg, respectively, which meets the European Commission Regulation No. 835/2011.

Influence of Graphene Reduction and Polymer Cross-Linking on Improving the Interfacial Properties of Multilayer Thin Films.

Graphene is a versatile composite reinforcement candidate due to its strong mechanical, tunable electrical and optical properties, and chemical stability. However, one drawback is the weak interfacial bonding, which results in weak adhesion to substrates. This could be overcome by adding polymer layers to have stronger adherence to the substrate and between graphene sheets. These multilayer thin films were found to have lower resistance to lateral scratch forces when compared to other reinforcements such as polymer/clay nanocomposites. Two additional processing steps are suggested to improve the scratch resistance of these films: graphene reduction and polymer cross-linking. Graphene/polymer nanocomposites consisting of polyvinylamine (PVAm) and graphene oxide (GO) were fabricated using the layer-by-layer assembly (LbL) technique. The reduced elastic modulus and hardness of PVAm/GO films were measured using nanoindentation. Reducing GO enhances mechanical properties by 60-70% while polymer cross-linking maintains this enhancement. Both graphene reduction and polymer cross-linking show significant improvement to scratch resistance. Particularly, polymer cross-linking leads to films with higher elastic recovery, 50% lower adhesive and plowing friction coefficient, 140 and 50% higher adhesive and shear strength values, respectively, and lower material pileup and scratch width/depth.