Major Aroma Compounds Research Articles

The aroma profile and aroma-active compounds of Brassica oleracea (kale) tea.

This study was to understand characteristic aroma properties of kale tea made by roasting kale leaves by profiling its aroma composition and screening its aroma-active compounds. Secondary metabolites of glucosinolates such as ally isothiocyanate, 3-butenyl isothiocyanate, 3-methylthiopropyl isothiocyanate, and 5-methylthiazole were the primary aroma compounds of raw kale but were less abundant in kale tea. Dimethyl trisulfide, cyclohex-2-en-1-ol, benzeneacetaldehyde, and 4-vinylguaiacol were quantitatively major aroma compounds in kale tea. Pyrazines, aldehydes, sulfides, and 4-vinylguaiacol were newly produced only in kale tea. In particular, 2-ethyl-6-methylpyrazine exhibiting the highest flavor dilution factor was the most potent aroma-active compound of kale tea, followed by methional, 2-ethyl-5-methylpyrazine, 2,5-dimethylpyrazine, 2,6-dimethylpyrazine, two unknown compounds, dimethyl disulfide, furfural, benzaldehyde, and dimethyl trisulfide. These compounds contributed to roasted, sulfur-like/pungent, and sweet aroma characteristics, which were main aroma properties of kale tea. In addition, (E)-hex-2-enal and (Z)-hex-3-en-1-ol contributed to the green and grassy aromas of kale tea.

Nutritional Values of Tung Samrit Jasmine Rice for Geographical Indication in Nakhon Ratchasima Province

The nutrition values of jasmine rice, i.e., Khao Dowk Mali (KDM) 105, from the Tung Samrit area covering 14 districts of Nakhon Ratchasima province of Thailand, were analyzed during the production seasons in 2015 and 2016. The analyzed values involved moisture, carbohydrate, protein, fat, energy, ash, vitamin E, vitamin B1, niacin B3, iron, zinc, and 2-acetyl-1-pyrroline (2-AP) contents. One of the values, 2-AP, a major aroma compound, showed significantly higher the other kinds of rice (2.71±0.05 (mg/100 g)). The comparison to the literature suggests that the rice product from the Tung Samrit area is up to the national standard. In addition to the use in the documentation for the geographical indication (GI) registration, the collaborated plans and policy were derived with the participation of farmers, dealers, and government agencies to promote sustainable “Tung Samrit jasmine rice”. HIGHLIGHTS Estimation of nutrition values of jasmine rice collected from the Tung Samrit area covering 14 districts of Nakhon Ratchasima province of Thailand Highly accumulation of 2-AP in Tung Samrit jasmine rice Tung Samrit jasmine rice is promote to Thailand geographical indication GRAPHICAL ABSTRACT

Fast HILIC Method for Separation and Quantification of Non-Volatile Aromatic Compounds and Monosaccharides from Willow (Salix sp.) Bark Extract

Willow bark water extracts contain a mixture of chemically heterogeneous compounds. Fast screening techniques of the extracts are often needed to obtain information on the profile of bioactive and/or other valuable components in the extract. This is, however, a challenging task due to the different chemical structures of the components. Willow bark extract from the hybrid Karin contains several bioactive compounds such as aromatic picein, triandrin, and (+)-catechin. Willow bark extract also contains significant amounts of the monosaccharides fructose and glucose. Here, we demonstrate the applicability of hydrophilic interaction liquid chromatography, coupled with evaporative light scattering and ultraviolet detectors, for the simultaneous separation and quantification of major aromatic compounds and monosaccharides from the willow bark extract. The ternary eluent mixture consisting of acetonitrile, water, and methanol enabled the baseline separation of the main components in the extract in a short analysis time, which makes this method ideal for fast screening of the plant extracts and investigating the purity of fractionated bioactive compounds.

Potential valorization of Cornelian cherry (Cornus mas L.) stones: Roasting and extraction of bioactive and volatile compounds

This study aimed to characterize the antioxidant potential, bioactive and volatile compounds of the stones from fruits of Cornus mas.Both fresh and roasted stones show a high antioxidant potential (166.48–509.74 μmol TE/g dw stones), which significantly depends on the cultivars. The roasted stones preserved 43.6% (DPPH; ‘Raciborski’) to 97.2% (FRAP; ‘Alesha’) of the antioxidant activity of the non-roasted stones. In the stones, two iridoids and ellagic acid were determined. During roasting, loganic acid remained stable, whereas cornuside was completely degraded. The analyses showed a 30-fold increase in the concentration of ellagic acid and in the formation of two of its derivatives. The major aroma compound of the roasted stones was furfural, but we also identified 18 pyrazine derivatives.This study is the first attempt to valorize Cornelian cherry stones via roasting. The roasted stones can be a coffee substitute, or aromatic and bioactive additions to cereal coffees.

Characterization of volatile compounds of liquid smoke flavourings from some tropical hardwoods

The aim of this study was to determine the chemical composition of the liquid smoke flavouring obtained from the pyrolysis of five tropical kinds of wood. Chemical characterization was performed by FT-IR and GC/MS on liquid smoke fractions soluble in dichloromethane. FT-IR spectroscopy revealed the presence of specific functional groups and chemical bonds of certain volatile compounds in liquid smoke. Besides, the chemical composition of this volatile fraction was also studied by GC/MS technique. Furfural, phenol,2‑methoxy-, creosol, and phenol,4-ethyl-2‑methoxy- were the aromatic compounds detected in greater proportion in all samples. The analysed liquid smoke flavourings showed differences in terms of proportions of the major aromatic compounds and also as regards the absence or presence of certain volatile compounds detected. The results suggest that all these woods are suitable for exploitation in the smoking food industry because they produce smoke containing large proportions of aromatic substances classified amongst the most flavour and odour-active compounds.

Method Development and Validation with Statistical Analysis to Access Raspberry Ketone Metabolism in Mice by UHPLC-QqQ-MS/MS

Abstract Objectives Raspberry ketone (4-(4-hydroxyphenyl)-2-butanone) (RK) is the major aroma compound of red raspberries and used commercially as flavoring agent. It is now gaining attention as a weight loss supplement. This work aimed to establish atargeted ultra-high performance liquid chromatography triple quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS) method for analysis of raspberry ketone and its 25 associated metabolites in mouse plasma and brain. Methods Dispersion and projection analysis and central composite design were used for LC-MS method optimization. Random effect analysis of variance was applied for validation inference and variation partition. Within this framework, repeatability, a broader sense of precision, was calculated as fraction of accuracy variance, reflecting instrumental imprecision, compound degradation and carry-over effects. Multivariate correlation analysis and principle component analysis were conducted, revealing underlying interlinkage and association among the manifold of method traits. R programming was engaged in streamlined statistical analysis and data visualization. Results The developed and validated method for RK and 25 metabolites had accuracy, matrix effect, recovery and processing efficiency bound mostly within the 80∼120% range, precision error below 5%, limit of quantification at 0.4∼6.0 ng/mL and linear range across three orders of magnitude. Two particular phenomena, the analytes’ background existence in the enzyme solution used for phase II metabolites deconjugation, and the noted liability of analytes in pure solvent at 4 °C vs. elevated stability in biomatrices, were found critical to method development and validation. Conclusions The UHPLC-QqQ-MS/MS method developed and validated provided an important tool for further investigation of RK metabolism and bioavailability. Funding Sources National Institutes of Health.

Dual-fiber solid-phase microextraction coupled with gas chromatography–mass spectrometry for the analysis of volatile compounds in traditional Chinese dry-cured ham

For the purpose of obtaining a more comprehensive flavor profile, volatile compounds in traditional Chinese dry-cured hams were studied by dual-fiber solid-phase microextraction (SPME) using two fibers simultaneously. By using the selected pair of fibers and under the optimal extraction time, there were total seventy-two volatile compounds identified, which was higher than the mono-fiber SPME method using a single fiber. Out of the seventy-two compounds, twenty-six compounds were not detected by using mono-fiber SPME and five among them are classified as the major aromatic compounds in the literatures. Due to the higher coverage and less tendency for the occurrence of competition among the volatiles, the total amount of volatiles extracted by dual-fiber SPME (510.02 ng/kg) was higher than mono-fiber SPME. Three grades of dry-cured hams were successfully distinguished based on dual-fiber SPME. The volatile compounds belonged to nine chemical families and differed in different grades of dry-cured hams. These results show that dual-fiber SPME is capable of analyzing flavor profiles more comprehensively and distinguishing traditional Chinese dry-cured hams.

Effects of Blackcurrant Fibre on Dough Physical Properties and Bread Quality Characteristics

Wheat flour was partially replaced with blackcurrant pomace, soluble, and insoluble dietary fibre in dough and bread formulations. The impact of blackcurrant fibre on physical properties of doughs and breads was probed using a set of complementary physicochemical techniques. The effect of fibre on aromatic profile of substituted breads was performed using analysis of volatile compounds. Analysis of fibre-substituted doughs and breads revealed that supplementation with pomace or insoluble fibre at concentrations >5% w/w or with pectin at concentrations >0.5% w/w alters their overall physicochemical responses. Pomace and pectin primarily acted as water-binders and decreased the extent of gluten hydration but insoluble fibre did not bind water to the same extent suggesting higher interaction capacity between its cellulosic components and gluten proteins resulting in formation of stiffer doughs. More than one hundred volatiles were determined with alcohols, furan derivatives and aldehydes being the major aromatic compounds.

Volatile Organic Compounds Profile Obtained from Processing Steps of Pacific Oysters (Crassostrea gigas) as Perspective for Food Industry

ABSTRACTIn the heat treatment of oysters, many aroma compounds are lost in the cooking steam and water. In this study, aroma compound profiles from oyster processing were identified by gas chromatography- mass spectrometry (GC-MS). The compounds were extracted by headspace-solid phase microextraction (HS-SPME), while the best process conditions such as temperature, extraction time, and desorption time were studied. The aroma compounds were obtained from raw oysters, from oysters after thermal treatment, from water released from raw oysters, from cooking steam, and from oyster boiling juice. All compounds were identified and semi-quantified by GC-MS. The major oyster aroma compounds were 1-octen-3-ol, hexanal, and benzaldehyde. Most of the components from oysters were lost both to the cooking steam and to the oyster boiling juice. The concentration range of volatile organic compounds transferred for oyster boiling juice between 14 and 90 mg L−1 shows that the residues from oyster processing have great technological potential, and they can be recovered for application as aromas by the food industry.

Effects of vineyard ‘potential’ and grape maturation on the aroma-volatile profile of Grenache wines

Background and aims: Wine is a beverage characterized by its pleasant aromatic features. These sensory notes are determined by the specific concentrations of odorous chemical compounds in each wine. Many of these aroma compounds arise directly or indirectly from the grapes, and their formation is affected by both grape metabolism and the viticultural ecosystem. Two studies were done with the 2015 vintage of Vitis vinifera L. cv. Grenache in Denominación Origen Somontano, a wine region of northern Aragon, Spain. In one study, we analysed wine from vineyards with different potentials: high potential, defined by balanced yield and high exposed leaf area (surface foliaire exposée, SFE, expressed in square metres) relative to production (P, expressed as kilograms of grapes) (i.e. high SFE:P ratio); and low potential, defined by unbalanced yield and low SFE:P ratio. In the other study, we analysed wine produced from grapes harvested at different times and therefore at different stages of ripening. The aim was to determine the effects of these variables on the aromatic compound profile of the wines.
 Methods and results: Concentrations of major aroma compounds were determined by gas chromatography (GC) with flame ionization detection, those of minor and trace aroma compounds by GC–mass spectrometry (MS), and those of pyrazines by thermal desorption–GC coupled with GC–MS. In the first study, wines from high-potential vineyards had higher concentrations of some compounds, such as esters of fermentative origin (isoamyl acetate, ethyl lactate and diethyl succinate), esters of varietal origin (ethyl dihydrocinnamate, methyl vanillate and ethyl vanillate), and terpenols (linalool and geraniol). In contrast, wines from low-potential vineyards had higher concentrations of 3-isopropyl-2-methoxypyrazine, γ-nonalactone and volatile phenols. In the second study, concentrations of varietal compounds such as rotundone and linalool increased with extended maturation. Furthermore, as ripening progressed, the ester to acid ratio for linear fatty acid ethyl esters generally increased while that for branched fatty acid ethyl esters tended to decrease. Acetaldehyde concentration was decreased in wines produced from grapes harvested at the latest date, a result that may be related to increased polyphenol content.Conclusions: The results of these studies provide an approximation of how the aromatic compound profile of a Grenache wine may differ between vineyards with different characteristics.Significance and impact of the study: We suggest explanations for these differences, which may guide the choice of harvest date.

The general and volatile properties and the quality of two newly selected Satsuma clones (11/1 İzmir and 30/ İzmir) grown under Mediterranean ecological conditions

Abstract The general and volatile properties, and the quality of two new Satsuma clones – 11/1 Izmir and 30/Izmir – selected under a Citrus Bud Wood Selection Program, were compared with Owari Satsuma samples grown under Adana ecological conditions. Gas chromatography, mass spectrometry, flame ionization detection (GC/MS/FID) analysis was used in the identification and quantification of the aromatic compounds, and a sensory profile analysis was performed to complete the general understanding using chemical analysis. The general analysis showed that the clone samples have higher yields, are more intense in skin color and more acidic; however, the total soluble solids and total sugar amount are lower than the Owari Satsuma samples. The terpenes are the major aromatic compound class. Along with other terpenes, there were significant amounts of dl-limonene followed by γ-terpinene, β-elemene, linalool and α-terpineol. The sensory analysis showed that the Owari Satsuma samples are sweeter and riper, with a better floral, spicy-citrus flavor than both clones. Both clones had a lower “Overall liking” rating than the Owari Satsuma samples.

LC‐DAD‐ESI‐MS/MS and GC‐MS profiling of phenolic and aroma compounds of high oleic sunflower oil during deep‐fat frying

Sunflower oils obtained after frying potatoes for different times (1, 5, and 10) and non-fried oils were analyzed. In total, 43 aroma substances were identified by GC-MS analyses and aldehydes were detected as the main chemical group. The concentration of aldehydes increased with the frying process and among them, (E,E)-2,4-decadienal, (E)-2-heptenal, and hexanal were found to be the major aroma compounds. High performance liquid chromatography with diode array detector, coupled with mass in tandem mode, were employed for quantitative and qualitative analysis of phenolic compounds. Rutin was the major phenolic compound in sunflower oils followed by chlorogenic acid, and they constituted the largest proportion of the total phenolic content in all oil samples. The concentration of phenolic compounds of sunflower oil revealed essential changes during several thermal processes and underwent degradation during heating. Only about 2% of its initial content presented after 10 frying process. Practical applications The present study explores the effects of the deep-fat frying process on aroma and phenolic compositions of sunflower oil. The cooking technique plays a significant role in the expanding global food industry. The findings of the research could be helpful for standardizing and preserving the taste, aroma, and nutritional value of the used oils and foods. Additionally, for the researchers, this study would give insight for identification and qualification phenolic and aroma compounds of sunflower oil.

Comparative profiling of volatile compounds in the grains of rice varieties differing in their aroma

Rice (Oryza sativa L.) is a staple food for more than half of the world’s population. Aromatic rice is highly preferred by most of the rice consumers and the aroma in Pusa Basmati 1 is said to be contributed by the accumulation of 2-acetyl-1-pyrroline (2AP). Our preliminary sensory tests identified that some of the rice genotypes including a traditional genotype of North-Eastern hill regions namely Chakhao Amubiexhibit entirely different aroma. Identifying alternate sources for aroma in rice and understanding its genetic basis will accelerate the development of rice varieties with desirable aroma. This study was aimed at developing a reliable extraction and profiling method for analyzing aromatic compounds in rice. KOH mediated digestion of grain flour followed by trapping of volatile compounds using sample collection tube containing Sorbent: Tenax GR and GC-MS separation of volatiles identified key differences between non-aromatic Improved White Ponni and aromatic Pusa Basmati 1. More than 50 volatile organic compounds (VOCs) were detected. A major aromatic compound 2-acetyl-1-pyrroline (2AP, (C6H9NO)) was detected only in the grains of Pusa basmati 1 but not in Improved White Ponni. Apart from 2AP, several other aromatic hydrocarbons and aldehydes such as hexanal, benzaldehyde, and2-pyrroline were detected in Pusa Basmati 1.Outcomes of this study are identification of several aromatic compounds in rice and also paved way for identifying novel aromatic compounds in rice.

Differential Accumulation of Aroma Compounds in Normal Green and Albino-Induced Yellow Tea (Camellia sinensis) Leaves.

Tea (Camellia sinensis) cultivars with green leaves are the most widely used for making tea. Recently, tea mutants with white or yellow young shoots have attracted increasing interest as raw materials for making “high-quality” tea products. Albino teas are generallycharacterized as having metabolites of relatively high amino acid content and lower catechin content. However, little is known about aroma compounds in albino tea leaves. Herein, we compared original normal leaves (green) and light-sensitive albino leaves (yellow) of cv. Yinghong No. 9. GC-MS was employed to analyze endogenous tea aroma compounds and related precursors. Quantitative real time PCR was used to measure expression levels of genes involved in biosyntheses of tea aromas.The total contents of most endogenous free tea aromas, including aroma fatty acid derivatives, aroma terpenes, and aroma phenylpropanoids/benzenoids, and their glycosidically bound aroma compounds, were lower in yellow leaves than in green leaves. The content of the key precursor geranyl diphosphate (GDP) and expression levels of key synthetic genes involved in the formation of linalool, a major aroma compound in cv. Yinghong No. 9, were investigated. Linalool content was lower in albino-induced yellow leaves, which was due to the lower GDP content compared with normal green leaves.

Identification of Floral Fragrances and Analysis of Fragrance Patterns in Herbaceous Peony Cultivars

Thirty herbaceous peony (section Paeonia of the genus Paeonia) cultivars were divided into four groups (no fragrance, light fragrance, medium fragrance, or intense fragrance) based on their sensory evaluation scores. Using dynamic headspace sampling (DHS) and automatic thermal desorption–gas chromatography/mass spectrometry (ATD-GC/MS), 130 volatile organic components were detected in these 30 cultivars and a total of 72 compounds were identified as scent components. The main compounds were phenylethyl alcohol, β-caryophyllene, linalool, (R)-citronellol, and nerol. Selecting α-pinene as the standard, the volatile components of these cultivars were quantitatively analyzed. By combining the sensory evaluation scores and the results of quantitative analysis, we found that ‘Going Bananas’, ‘Cream Delight’, ‘Zhu Sha Pan’, ‘Qiao Ling’, ‘Duchess de Nemours’, and ‘Yang Fei Chu Yu’ displayed an intense fragrance and, thus, had relatively high commercial value for the flower fragrance industry. ‘Red Magic’, ‘Joker’, ‘Fairy Princess’, ‘Lovely Rose’, ‘Carina’, and ‘Etched Salmon’ were excluded from the hierarchical cluster of aromatic compounds and the analysis of fragrance patterns because of the low amount of fragrance they released and poor sensory evaluation results. Based on a cluster analysis, assessment of the major aromatic compounds, and the results of sensory evaluation, the remaining 24 cultivars were divided into five fragrance patterns for the first time: woody scent [cluster I (major fragrance β-caryophyllene)], fruity scent [cluster II (phenylethyl alcohol)], lily scent [cluster III (linalool)], rose scent {cluster IV [(R)-citronellol]}, and an orange blossom scent [cluster V (nerol)].

Effect of free fatty acids and lipolysis on Sauvignon Blanc fermentation

Background and Aims The volatile thiols, such as 3-mercaptohexanol, 3-mercaptohexyl acetate and 4-mercapto-4-methylpentan-2-one, are major aroma compounds responsible for the distinctive tropical notes (passionfruit and grapefruit) in New Zealand Sauvignon Blanc wines. Previously, it was observed that traces of linoleic acid in grape juice can significantly affect the development of these volatile thiols and other aroma compounds in wine. Here, we examined the effect of the fatty acids commonly found in Sauvignon Blanc grape juice as well as juice lipid lipolysis on the development of aroma compounds in the resulting wines. Methods and Results Experiments were performed to increase the total free fatty acid concentration in grape juice through juice treatment with acidic lipase from Aspergillus niger and through co-cultured fermentations with non-Saccharomyces lipase-secreting yeasts. We observed a significant reduction in the production of 3-mercaptohexyl acetate in fermented wines upon supplementation with linoleic acid and lipase. Supplementation with lipase increased the concentration of 3-mercaptohexanol and all ethyl esters detected, while reducing the development of acetate esters. Co-cultured fermentations also affected the development of many classes of aroma compounds. Conclusions This study demonstrated that the aroma profile of wines could be effectively manipulated by altering the amount of free unsaturated fatty acids in grape juice through lipolytic enzyme supplementation or co-fermentation with non-Saccharomyces lipolytic yeast species. Significance of the Study The key findings of this study may lead to new winemaking strategies through the manipulation of the lipid component of grape juice.

The Correlation between 2-Acetyl-1-pyrroline Content, Biological Compounds and Molecular Characterization to the Aroma Intensities of Thai Local Rice.

Aroma intensities of rice are correlated with the mixture of aroma compounds it contains. 2-acetyl-1-pyrroline (2AP) has been reported as a major aroma compound and as a characteristic compound in fragrant rice. In this study, Thai local cultivars were classified into fragrant and non-fragrant rice based on the 2AP content and molecular characterization. Local rice cultivars were also examined for their proline content and volatile compounds profile, which are important factors in determining aroma. The results suggested that 43 Thai local rice cultivars were classified into 25 fragrant rice cultivars and 18 non-fragrant cultivars. The type of fragrant rice cultivars included 16 non-colored and 9 colored rice cultivars, while the type of non-fragrant rice cultivars included 14 non-colored and 4 colored rice cultivars. The proline content of local rice cultivars was determined and showed no correlation with the 2AP content; however, the proline level appears to be associated with the environmental stress in the rice cultivation area. One hundred and forty volatile compounds were identified from local rice cultivars. Among the detected compounds, 18 volatile compounds, including hexanal 1-pentanol octanal (E)-2-heptenal 6-methyl-5-hepten-2-one 1-hexanol nonanal 2-butoxy-ethanol (E)-2-octenal 1-tetradecene 1-octen-3-ol decanal benzaldehyde (E)-2-nonenal 1-nonanol benzyl alcohol isovanillin and vanillin contributed to the aroma intensities of both fragrant and non-fragrant rice. Aroma compounds were more abundant in fragrant than in non-fragrant rice. Moreover, the levels of aroma compounds recorded in non-colored cultivars were higher than those in colored rice cultivars. In contrast, the 2AP content of colored rice cultivars was higher than that in non-colored rice cultivars. Our findings may assist rice breeding programs in producing a new aromatic genotype rice with high potential aroma intensities.

Chemical composition and sensory profiles of mulberry wines as fermented with different Saccharomyces cerevisiae strains

ABSTRACTThe aim of this article was to study the influence of Saccharomyces cerevisiae strains on the chemical composition and sensory properties of mulberry wines. For this purpose, three Saccharomyces cerevisiae strains, YJM 681 (isolated from raspberry), ySR 127 (commercial yeast) and Y1 (isolated from kefir fermented milk) were used for the alcoholic fermentation of mulberry juice. Yeast strains had deep influences on oenological, phenolic, amino acid, volatile and sensory profiles of resulting mulberry wines. Specifically, the beverages fermented with YJM 681 were characterised by relatively high volatile acidity and high contents of total flavonols, amino acids and some phenolic acids, including protocatechuic acid, p-hydroxybenzoic acid, caffeic acid and veratric acid. Samples fermented with ySR 127 possessed higher cyanidin-3-O-glucoside content, whereas, total amino acid content was markedly lower than that of other samples. Furthermore, mulberry wines fermented with Y1 showed the lowest volatile acidity and the lowest contents of total anthocyanins and tartaric esters. The amounts of major aromatic compounds, including 1-propanol, 2-methyl-1-propanol and ethyl acetate inside were also smaller than that of samples fermented with YJM 681 and ySR 127. Besides, the sensory results revealed that mulberry wines fermented with Y1 exhibited the lowest intensity of fruity aroma, while samples fermented with ySR 127 had the strongest sour and sweet tastes and aftertaste. These findings provide fundamental knowledge about the influence of yeast strains on the quality of mulberry wine.

Raspberry Ketone Reduced Lipid Accumulation in 3T3-L1 Cells and Ovariectomy-Induced Obesity in Wistar Rats by Regulating Autophagy Mechanisms.

This study aimed to determine the antiobesity effects of raspberry ketone (RK), one of the major aromatic compounds contained in raspberry, and its underlying mechanisms. During adipogenesis of 3T3-L1 cells, RK (300 μM) significantly reduced lipid accumulation and downregulated the expression of CCAAT/enhancer-binding protein α (C/EBPα), peroxisome proliferation-activated receptor γ (PPARγ), fatty acid-binding protein 4 (FABP4), and fatty acid synthase (FAS). RK also reduced the expression of light chain 3B (LC3B), autophagy-related protein 12 (Atg12), sirtuin 1 (SIRT1), and phosphorylated-tuberous sclerosis complex 2 (TSC2), whereas it increased the level of p62 and phosphorylated-mammalian target of rapamycin (mTOR). Daily administration of RK decreased the body weight (ovariectomy [Ovx] + RK, 352.6 ± 5 vs Ovx, 386 ± 5.8 g; P < 0.05), fat mass (Ovx + RK, 3.2 ± 0.05 vs Ovx, 5.0 ± 0.4 g; P < 0.05), and fat cell size (Ovx + RK, 6.4 ± 0.6 vs Ovx, 11.1 ± 0.7 × 103 μm2; P < 0.05) in Ovx-induced obesity in rats. The expression of PPARγ, C/EBPα, FAS, and FABP4 was significantly reduced in the Ovx + RK group compared with that in the Ovx group. Similar patterns were observed in autophagy-related proteins and endoplasmic reticulum stress proteins. These results suggest that RK inhibited lipid accumulation by regulating autophagy in 3T3-L1 cells and Ovx-induced obese rats.

Hydrothermolysis of organosolv lignin for the production of bio-oil rich in monoaromatic phenolic compounds

Bio-oils rich in monoaromatic phenolic compounds were produced by a hydrothermal treatment in a batch reactor from organosolv lignin derived from beech wood. Reaction temperatures and times were varied (270–350°C and 10–120min, respectively). Increase in the temperature at a particular reaction time had a positive impact on the bio-oil yields, which varied from 8.0wt% to 14.6wt%, based on the original amount of dry lignin. GC–MS analysis of bio-oils revealed that the yields of monoaromatic compounds ranged from 22 to 65wt% of bio-oil depending on the reaction conditions. Syringol (8.9–22.8wt% of bio-oil), guaiacol (2.6–9.3wt% of bio-oil), pyrocatechol (0–12.4wt% of bio-oil), 3-methoxycatechol (0–21wt% of bio-oil), 4-methylsyringol (0.5–5.9wt% of bio-oil), and syringaldehyde (0–9wt% of bio-oil) were identified as the major aromatic compounds. In addition to bio-oil, gaseous components, water solubles, char, and undegraded lignin were formed in the experiments. The mass balances of the experiments were constructed. The results show that monoaromatics can be produced at a moderate yield through uncatalysed lignin hydrothermolysis; char formation remains as an obstacle, however, and its prevention calls for the usage of catalysts and/or organic solvents.