Aroma Extract Research Articles

Comparison of key aroma-active compounds between roasted and cold-pressed sesame oils

This was the first study to compare the key aroma-active compounds that contributed to the different aroma profiles between roasted and cold-pressed sesame oils. Aroma compounds were extracted by headspace solid-phase micro-extraction (HS-SPME) and simultaneous distillation extraction (SDE) and were analysed using gas chromatography–olfactometry-mass spectrometry (GC-O-MS) and aroma extract dilution analysis (AEDA). The numbers of aroma-active compounds with the flavour dilution (FD) factors between 1 and 2048 were 57 and 16 in the roasted and cold-pressed sesame oils, respectively. A total of 28 volatile compounds were identified as aroma-active compounds in sesame oils for the first time. Important aroma compounds (FD ≥ 8) were quantified by the external standard method, and their odour activity values (OAV) were calculated as the ratio of their concentrations to odour thresholds in oil. The numbers of key aroma-active compounds defined by OAVs ≥ 1 were 23 (OAVs = 1–385) and 8 (OAVs = 1–42), respectively, in the roasted and cold-pressed sesame oils. 2-Methoxy-4-vinylphenol (smoked, 1924 µg/kg, OAV = 385), 2-methoxyphenol (smoked, 1488 µg/kg, OAV = 114) and pyrazines (roasted and nutty, 578–22750 µg/kg, OAV = 1–67) were the most important aroma-active compounds in the roasted sesame oil, whereas hexanal (green and fruity, 3094 µg/kg, OAV = 42) was the most important aroma-active compound in the cold-pressed sesame oil, followed by (E,E)-2,4-decadienal (earthy, 4170 µg/kg, OAV = 31), dimethyl sulfone (sulphur-like, 406 µg/kg, OAV = 20) and octanal (green and fruity, 901 µg/kg, OAV = 16). This study provides valuable information for manufacturers to achieve precise flavour control of sesame oil products.

GC-IMS and olfactometry analysis on the tea aroma of Yingde black teas harvested in different seasons

This study aims to investigate the influence of different harvesting seasons on the aroma of black tea and the trend in the tea aroma variation. A total of 68 volatile substances was identified by gas chromatography coupled with ion-mobility spectrometry (GC-IMS), and 20 characteristic aroma-active compounds were quantitatively analyzed by gas chromatography-olfactometry coupled with aroma extract dilution analysis (GC-O AEDA) and odor activity value (OAV) analysis. These aroma-active compounds are mainly linalool, β-damascenone, and benzeneacetaldehyde. Both methods confirmed that the aroma of tea changes with the harvesting seasons, showing a downward trend followed by an upward trend. Besides, black teas harvested in different seasons have their characteristic volatile compounds and metabolism precursors. The degradation of glycosides, carotenes, and amino acids are the most important degradation pathways for the formation of tea aroma. The PLSR results of GC-O-AEDA, OAV, and DSA data agree with each other, showing that five aroma attributes of the autumn tea have strong correlations. The autumn tea has the richest aroma, followed by the spring tea and the summer tea.

Characterization of odor-active compounds in high-salt liquid-state soy sauce after cooking

GC × GC–O–MS was used for the aroma extract dilution analysis of cooked high-salt liquid-state soy sauce (HLS), wherein a number of components exhibited high flavor dilution (FD) factors. Electronic nose analysis showed that the heating temperature had a greater influence on the odor characteristics of soy sauce than the heating time. Sensory evaluation and the FD factor of odor-active compounds suggested that the caramel-like/sweet, roasted/roasted nut-like and spicy/burnt odor intensities of the boiled soy sauce were stronger than following heating at a higher temperature. These results indicate that different heating conditions could change the intensities of caramel-like/sweet, roasted/roasted nut-like and spicy/burnt in soy sauce during cooking by the concentrations changing of corresponding odor-active compounds. This study can provide basic data for the application of HLS aroma in food processing, and provides a reference for the application of HLS aroma in daily cooking and diet.

Chemo-sensory characterization of aroma active compounds of native oak wood in relation to their geographical origins

Oak wood contains aroma-active compounds that contribute significantly to the chemical structure, olfactory and gustatory qualities of alcoholic beverages and vinegars as by-products that have been either fermented and/or aged in oak barrels. The chemical composition of cooperage oak is highly variable, depending on the degree of toasting and natural seasoning. However, it is unclear whether the odor of oak varies according to different geographical regions and pedoclimatic conditions. Especially in view of the actual challenges in forestry in relation to climate change, the present study aimed at elucidating the odorous constituents of nine natural oak samples from Germany, Austria and Hungary with respect to these influencing parameters. The odor profiles of the oaks were compared, the potent odorants were determined, and selected odorants were quantified using stable isotope dilution assays (SIDA). The majority of the identified odorants in all samples were fatty acid degradation products, followed by a series of odorants with terpenoic structure and others resulting from the degradation of lignin. Several different odorants including 2-propenoic acid and cinnamaldehyde are reported here for the first time in oaks from different growth regions. Odor activity values (OAVs), calculated based on odor thresholds (OTs) in water, revealed hexanal, (E)-2-nonenal, (Z)-3-hexenal, eugenol, vanillin, and whiskey lactone as potent odorants for the oak odor. Principal component analysis of the data obtained from sensory evaluation, comparative aroma extract dilution analysis (cAEDA) and their corresponding quantified odorants showed that the highest separation rate was obtained for Hungarian oak, whereas Austrian and Bavarian oak samples were more similar. Recombination experiments by mixing the dominant odorants in their naturally occurring concentrations revealed a good agreement of the smell properties of the model mixture with the smell of the respective original sample. These findings aimat evaluating and establishing a better understanding of the distinctive smell of oak wood and demonstrated the prospects of new oak sources.

Studies on the key odorants in Maopu buckwheat finished Baijiu and the effect of tartary buckwheat extract on its flavor

Maopu buckwheat finished Baijiu (MBFB), a unique Chinese Baijiu, is mainly composed of base Baijiu and tartary buckwheat extract (TBE). However, there is a lack of studies reporting its flavor. In this study, the key odorants in MBFB were characterized for the first time using a sensomics approach. Forty-nine odorants were identified using gas chromatography-mass spectrometry/olfactory analysis, coupled with aroma extraction dilution analysis. They were quantified using multiple methods and their odor activity values were calculated. Ethyl hexanoate, ethyl butanoate, butanoic acid, hexanoic acid, dimethyl trisulfide, p-cresol, β-damascenone, and 3-methylbutanal were confirmed as the key odorants in MBFB using recombination and omission experiments. Furthermore, the interaction between TBE and odorants were revealed that TBE enhanced the sweet notes, while it inhibited the alcoholic, acidic, and fruity notes, which might be because TBE promoted the volatility of most esters, but inhibited the volatilities of butanoic acid and hexanoic acid.

Variation in Volatile Flavor Compounds of Cooked Mutton Meatballs during Storage.

Solid phase microextraction (SPME) and Solvent-Assisted Flavor Evaporation (SAFE) were used to analyze the flavor changes of cooked mutton meatballs during storage by gas chromatography-olfactometrymass spectrometry (GC-O-MS), sensory evaluation and Partial Least Squares Regression (PLSR). With the increase of storage time, the concentrations of various volatile compounds in cooked mutton meatballs decreased to varying degrees at the later stage of storage, indicating that the aroma was gradually weakened, which was consistent with the results of sensory evaluation. At 30 days of storage, the overall aroma profile was more prominent, and at the later stage of storage, the sulfur odor was more prominent. The correlation of PLSR further confirmed the credibility of the results. Compared with the SPME and SAFE extraction methods, SPME extracted more flavor substances, and the SAFE extraction rate was higher, which indicated that the combination of several methods was needed for aroma extraction. An analysis of the dilution results and odor activity value (OAV) showed that the key aroma components during storage were 1-octene-3-ol, linalool, methylallyl sulfide, diallyl disulfide, 2-pinene, hexanal and butyric acid.

Characterization of the key aroma compounds in pork broth by sensory-directed flavor analysis.

The solvent-assisted flavor evaporation, sensory evaluation, and partial least squares regression analysis were used to screen the relatively better flavor of pork broth among different stewing time (1, 2, 4, 6, and 8 h). A total of 48 volatile compounds were successfully characterized by gas chromatography-mass spectrometry in the pork broth, which stewed for 4 h. The dominant volatiles were confirmed by aroma extract dilution analysis. Twenty-seven odorants with flavor dilution factors between 2 and 1,024 were identified. Among them, odor activity values of 19 components were greater than or equal to 1. An aroma recombination test was performed, and a similar flavor (93.04 %) was simulated. Omission test further confirmed that 4-hydroxy-2,5-dimethyl-3(2H)-furanone, hexanal, 1-octen-3-ol, (E)-2-octenal, (E)-2-decenal, (E)-2-undecanal, (E, E)-2,4-decadienal, nonanoic acid, decanoic acid, 2-heptanone, 3-hydroxy-2-butanone, δ-decanolactone, and 2-acetylpyrrole were the key odorants of the aroma profile of pork broth. PRACTICAL APPLICATION: Pork broth is popular in China, but lacks the study of its key aroma compounds, which restricts its industrial production. This study researched the optimum stewing time of pork broth and analyzed its key aroma compounds. Finally, the flavor profile can be obtained and understood. This study could provide a reference and further promote research on pork flavor.

Characterization of Odorants in Chardonnay Marc Skins.

Chardonnay marc, consisting of grape skins, seeds, and stems, is a coproduct of grape juice production for Chardonnay wine making. The discovery that marc contains a rich source of health-promoting molecules has led to its growing popularity as a flavorful healthy food ingredient. However, the odorants responsible for its pleasant fruity aroma remain unknown. In this study, 35 odorants were identified in Chardonnay marc skins using solvent-assisted flavor evaporation (SAFE) and aroma extract dilution analysis (AEDA). Thirteen odorants were quantitated employing stable isotope dilution assays (SIDAs), and odor activity values (OAVs) were calculated. Odorants with OAVs >1 included 3-methylnonane-2,4-dione (hay, OAV 5800), β-ionone (floral, violets, OAV 2900), (2E,4E)-nona-2,4-dienal (fatty, OAV 1200), β-damascenone (cooked apple, OAV 370), hexanal (green, OAV 260), oct-1-en-3-one (mushroom, OAV 200), linalool (floral, citrus, OAV 61), (2E,4E)-deca-2,4-dienal (fatty, OAV 60), 2-phenylethanol (floral, rose, OAV 16), 3-(methylsulfanyl)propanal (potato, OAV 3.7), HDMF (caramel, OAV 2.0), and ethyl octanoate (fruity, OAV 1.1). An odor simulation model prepared using odorants with OAVs >1 sensorially matched the aroma of the Chardonnay marc skins. This investigation establishes a foundation for future studies aimed at determining the contribution of individual Chardonnay marc components (skins, seeds, and stems) to the aroma profile of Chardonnay marc powder and aiding producers in delivering optimal and consistent aroma profiles by region.

Tandem Solid-Phase Extraction Columns for Simultaneous Aroma Extraction and Fractionation of Wuliangye and Other Baijiu.

Wuliangye baijiu is one of the most famous baijiu in China, with a rich, harmonic aroma profile highly appreciated by consumers. Thousands of volatiles have been identified for the unique aroma profile. Among them, fatty acid esters have been identified as the main contributors to the aroma profile. In addition, many non-ester minor compounds, many of which are more polar than the esters, have been identified to contribute to the characteristic aroma unique to Wuliangye baijiu. The analysis of these minor compounds has been challenging due to the dominance of esters in the sample. Thus, it is desirable to fractionate the aroma extract into subgroups based on functional group or polarity to simplify the analysis. This study attempts a new approach to achieve simultaneous volatile extraction and fractionation using tandem LiChrolut EN and silica gel solid-phase extraction (SPE) columns. A baijiu sample (10 mL, diluted in 40 mL of water) was first passed through the LiChrolut EN (1.0 g) column. The loaded LiChrolut EN column was then dried with air and coupled with a silica gel (5.0 g) SPE column with anhydrous Na2SO4 (10.0 g) in between. The volatile compounds were eluted from the LiChrolut EN column and simultaneously fractionated on the silica gel column based on polarity. The simultaneous extraction and fractionation technique enabled the fractionations of all fatty acid esters into less polar fractions. Fatty acids, alcohols, pyrazines, furans, phenols, hydroxy esters, and other polar compounds were collected in more polar fractions. This technique was used to study the volatile compounds in Wuliangye, Moutai, and Fengjiu baijiu. In addition to fatty acid esters, many minor polar compounds, including 2,6-dimethylpyrazine, 2-ethyl-6-methylpyrazine, 2-ethyl-3,5-dimethylpyrazine, p-cresol, and 2-acetylpyrrole, were unequivocally identified in the samples. The procedure is fast and straightforward, with low solvent consumption.

Study of the antioxidant properties of some aromatic plant extracts

In this study the effect of extraction conditions (time - temperature-type of aromatic plants-extraction method) on the antioxidant activity, pH extracts was investigated. The extraction process was carried out using water as a solvent, and also through using the ultrasonic treatment. Aromatic plants that have been used are rosemary, a mixture of herbs (black cumin+ oregano). The extracts were prepared by the solvent extraction method, and the ultrasonic treatment was under the following conditions: time - (10-20-30 min), temperature - (40-60-80°C ), then pH extracts were estimated using pH meter, and the antioxidant activity of all extracts was determined by scavenging of DPPH (1,1-diphenyl 2-picrylhydrazyl) radicals. The results have showed that the values of pH extracts increase in the use of ultrasonic treatment. Also it was revealed that the highest value of antioxidant activity (95.43 %) was when extracts were obtained from rosemary using ultrasonic treatment according to the following parameters: (60 °C, 30 min). Therefore, these conditions could be applied for further extraction for their use in the preparation of medicinal products or functional food.

Elucidation of the accelerated sulfur vulcanization of bio oil‐extended natural rubber compounds

AbstractThe elucidation of the role of bio‐oils on the accelerated sulfur vulcanization of natural rubber (NR) compounds is discussed in this study. Two types of bio‐oil, palm oil and soybean oil, were studied in direct comparison with a distillate aromatic extract oil (DAE) as a reference. The scorch and cure times of the bio‐oil‐extended NR compounds were shorter than those containing DAE. The use of bio‐oils gave a higher cure reaction rate constant along with a lower activation energy than the use of DAE. The attenuated total reflectance‐Fourier transform infrared spectroscopy analysis revealed that the fatty acid segment of the bio‐oils can react with zinc oxide to give zinc carboxylate, which is then involved in and promotes the vulcanization reaction. The use of bio‐oils to increase the rate of vulcanization strongly influenced the crosslink density of the obtained NR vulcanizates, yielding NR vulcanizates with a lower crosslinking density. It is proposed here that the bio‐oils might consume the curing agent via the reaction between their own unsaturated fatty acid and sulfur. This was supported by the increased viscosity of the oils after exposure to sulfur at a high temperature. The tensile strength and elongation at break of the bio‐oil‐extended NR compounds were lower and higher, respectively, than the NR extended with DAE oil due to the lower crosslink density of the bio oil‐extended NR vulcanizates.

Analysis of aroma-active compounds in four Chinese dry-cured hams based on GC-O combined with AEDA and frequency detection methods

Chinese dry-cured hams have become increasingly appreciated by consumers because of their unique flavor characteristics. In this study, the volatile compounds of four Yunnan dry-cured hams (Xuanwei, Nuodeng, Sanchuan, and Saba) were characterized by monolithic material sorptive extraction (MMSE) and GC-MS. A total of 66 volatile compounds were identified, of which aldehydes and alkanes were the most abundant (>76.43%) in all four hams. The PCA result with 71.04% of the variability demonstrated the potential dominant compounds for the different dry-cured hams. The similarities and differences of aroma-active compounds among the different Yunnan dry-cured hams were studied by using gas chromatography-olfactometry (GC-O) combined with aroma extract dilution analysis (AEDA) and frequency detection (FD) methods. The results demonstrated that 3-methylbutanal, hexanal, 2,6-dimethylpyrazine, 1-octen-3-ol, dimethyl trisulfide, and nonanal were the most important aroma-active compounds in the Yunnan dry-cured hams. This study contributes to a better understanding of odor quality in Chinese dry-cured hams.

Sensory-Based Identification of Aroma-Active Compounds in Hotpot Seasoning before and after Boiling.

Boiling, the most frequent edible way to hotpot seasoning (HS), exerts a significant impact on the aroma of HS. The present study employed, for the first time, a novel switchable system between GC-O-MS and GC×GC-O-MS (SGC/GC×GC-O-MS) to study the aroma compounds of HS and hotpot seasoning boiling liquid (HSBL). A total of 79 aroma compounds and 56 aroma-active compounds were identified. The aroma extract dilution analysis (AEDA) was used to analyze the differences between the key aroma-active components in the HS and HSBL. The results showed that 13 aroma-active components were significantly affected by boiling, such as D-limonene, methional, and linalool. Moreover, a total of 22 key aroma-active components were identified through the odor activity values (OAVs) calculation. Of them, (E)-2-octenal (fatty) and linalool showed a significant difference, suggesting them to be the most critical aroma-active compounds in the HSBL, and HS, respectively. Finally, the correlation between key aroma-active compounds and the sensory properties of HS and HSBL was studied. These results demonstrated that the OAVs of key aroma-active compounds could characterize the real information of samples through bidirectional orthogonal partial least squares (O2PLS). The analysis results were consistent with the sensory evaluation results.

Characterization of Odorants in a 10-Year-Old Riesling Wine.

Riesling wines are mostly enjoyed as young wines, usually consumed within the first few years after bottling. Throughout several years of aging, Riesling wines begin to develop more robust flavor profiles, often displaying less fruity and floral notes and more pronounced maple, honey, and caramel notes. A body of scientific literature has been conducted on the aroma chemistry of young Riesling wines; however, comparatively less scientific reports have been published on the aroma chemistry of aged Riesling wines, and a comprehensive aroma analysis of a 10-year-old Riesling wine has not been previously completed. In this study, a total of 36 odorants were identified in a 10-year-old aged Riesling wine using solvent-assisted flavor evaporation and aroma extract dilution analysis. A total of 26 odorants were quantitated by employing stable isotope dilution assays. Odorants with high odor activity values (OAV) included wine lactone (coconut, OAV 460), ethyl octanoate (fruity, OAV 240), ethyl hexanoate (fruity, OAV 97), β-damascenone (cooked apple, OAV 60), 5-ethyl-3-hydroxy-4-methyl-(5H)-furan-2-one (maple, OAV 33), (S)-ethyl 2-methylbutanoate (fruity, OAV 22), 3-(methylsulfanyl) propanal (cooked potato, OAV 20), ethyl 2-methylpropanoate (fruity, OAV 9.5), ethyl butanoate (fruity, 7.1 OAV), and 1,1,6-trimethyl-1,2-dihydronapthalene (petrol, OAV 6.4). An odor simulation model prepared from all the odorants with an OAV greater than 1 closely matched the sensory profile of the authentic wine. The results of this study provide insight about odorants present in a 10-year-old bottle aged Riesling wine, and this knowledge may be useful for future studies aimed at probing the influence of aging on the aroma chemistry of Riesling wines and other white wines.

Characterization of Key Aroma Compounds in Tartary Buckwheat (Fagopyrum tataricum Gaertn.) by Means of Sensory-Directed Flavor Analysis

The key odorants of tartary buckwheat (TB) were researched by a sensory-directed flavor analysis approach for the first time. After the volatiles of TB were isolated by solvent-assisted flavor evaporation (SAFE), 49 aroma-active components with flavor dilution (FD) factors in the range of 1-2187 were identified using gas chromatography-olfactometry-mass spectrometry (GC-O-MS) combined with aroma extract dilution analysis (AEDA). Geranylacetone, phenethyl alcohol, and β-damascone showed the highest FD factors of 2187. All 49 odorants were further quantitated by the internal standard curve method, and their odor activity values (OAVs) were obtained. The overall aroma of TB was successfully simulated (similarity > 98.16%) by mixing 16 odorants (OAV ≥ 1) with their natural concentrations. The omission tests revealed that geosmin, α-isomethylionone, α-methylionone, β-ionone, linalool, β-damascone, geranylacetone, guaiacol, ethyl hexanoate, geraniol, vanillin, tetrahydrolinalool, and 2,5-dimethyl-4-hydroxy-3-(2H)-furanone were the key odorants of TB. Chiral analysis showed that tetrahydrolinalool and linalool existed as racemics in the commercial TB. The relative content of R-enantiomers of α-isomethylionone and α-methylionone was slightly higher than that of their S-enantiomers. The odor thresholds of R- and S-enantiomer of tetrahydrolinalool were first detected as 0.029 and 3.8 μg/L in air, respectively.

Research on separation of aromatics from FCC diesel using organic solvent: A combination of experiments and quantum chemical calculations

Fluid catalytic cracking (FCC) diesel is the main contributor of polycyclic aromatic hydrocarbons (PAHs) in diesel, so reducing the content of PAHs in FCC diesel is of great significance to environmental protection and high-value utilization of FCC diesel. To understand the potential separation of dicyclic aromatic from FCC diesel, dimethyl sulfoxide (DMSO), 2-methoxyethanol (EGME), and N,N-dimethylformamide (DMF) were selected as extracting solvents. The liquid-liquid phase behavior of the dodecane + 1-methylnaphthalene + solvent systems was determined to investigate the solvent extraction ability, the values of S were calculated and the high selectivity of DMSO could be confirmed. Then, the quantum chemical calculation found that the extraction mechanism of DMSO and DMF was weak H-bond and van der Waals (VDW) forces, while that of EGME was only VDW force. Additionally, the structure-activity relationship between solvent molecular structure and solvent selectivity was obtained by combining the experimental results and the quantum chemical calculations, which could provide theoretical guidance for the selection of high separation performance solvents in the future. Finally, the binary interaction parameters of NRTL and UNIQUAC models were obtained with the root-mean-square deviation (RMSD) values all less than 0.60%, which provide basic data for the further simulation of aromatics extraction of FCC diesel.

Influence of solvent structure on the extraction of aromatics from FCC diesel and computational thermodynamics study

The separation of aromatics from fluid catalytic cracking (FCC) diesel is of great significance for environmental protection. The extraction ability of 1-methyl-2-pyrrolidinone (NMP), sulfolane (SUL), and 4-formylmorpholine (NFM) were studied by the liquid-liquid equilibrium (LLE) experimental, and the corresponding LLE data of NMP/SUL/NFM + 1-methylnaphthalene + dodecane systems were obtained. The calculated distribution coefficients and separation factors showed that the solubility of 1-methylnaphthalene was the highest in NMP and the selectivity of SUL to 1-methylnaphthalene was the strongest. The effects of solvent structures were investigated by a combination of experiments and quantum chemical calculations. The 1-methylnaphthalene is more soluble in solvents with planar molecular structure because the steric hindrance between the two molecules is smaller, and the group with more electronegative has higher selectivity for 1-methylnaphthalene. Moreover, the reduced density gradient (RDG) and atoms in molecules (AIM) analyzed found that the main extraction mechanism of the three solvents was van der Waals (VDW) and weak hydrogen bond, in which VDW was dominant. Finally, the binary interaction parameters of NRTL and UNIQUAC models were obtained, which make up for the blank in Aspen simulation for the separation of FCC diesel by organic solvents.

Value addition study on coker kero for producing alpha olefin and alkyl benzene

Abstract Coker kero stream is obtained from delayed coking which contains saturates with alpha olefins and PNA compounds which was physicochemical characterised. The fractions present in coker kero may be used further for value added products such as alkyl benzene and naphthalene etc. The study described potential of coker kero via aromatics and non-aromatics separation by using liquid-liquid extraction (LLE) with N-methyl pyrrolidone (NMP), acetonitrile and methanol as solvents of different polarity. Methanol imparts best colour improvement as per ASTM D-1500. Beside this, adsorption study on coker kero was performed using fuller’s earth, chalk powder, red ochre and wood-stick’s ash as adsorbents. The adsorption study suggested that fuller’s earth not only separate aromatics and non-aromatics form coker kero, but also acts as a better adsorbent than graphitic carbon (activated charcoal) and is found suitable for colour improvement comparatively. This study inferred the separation of polar components, improvement in the colour, odour and established the stable fuel. FT-IR study suggested that N-methyl Pyrrolidone gives better results comparatively other solvents. HC22 type analysis of coker kero raffinate and extract phase confirm the sharp extraction of coker kero feed using N-Methyl pyrrolidone as it is a good solvent for extraction of aromatics. GCMS and HRMS compositional analysis successfully performed for the coker kero and it is separated aromatic and non-aromatic fractions.

Identification and Screening of Potential Organic Solvents for the Liquid–Liquid Extraction of Aromatics

Identification and Screening of Potential Organic Solvents for the Liquid–Liquid Extraction of Aromatics

Effect of the Epoxide Contents of Liquid Isoprene Rubber as a Processing Aid on the Properties of Silica-Filled Natural Rubber Compounds.

In this study, we examined the feasibility of using epoxidized liquid isoprene rubber (E-LqIR) as a processing aid for truck and bus radial (TBR) tire treads and investigated the effects of the epoxide content on the wear resistance, fuel efficiency, and resistance to extraction of the E-LqIRs. The results confirmed that, compared to the treated distillate aromatic extract (TDAE) oil, the E-LqIRs could enhance the filler–rubber interactions and reduce the oil migration. However, the consumption of sulfur by the E-LqIRs resulted in a lower crosslink density compared to that of the TDAE oil, and the higher epoxide content decreased the wear resistance and fuel efficiency because of the increased glass-transition temperature (Tg). In contrast, the E-LqIR with a low epoxide content of 6 mol% had no significant effect on the Tg of the final compound and resulted in superior wear resistance and fuel efficiency, compared to those shown by TDAE oil, because of the higher filler–rubber interactions.