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Different bioproducts can be obtained by changing operative condition of biotechnological process, and this bioprocess aspect is a significant approach to be adopted on industrial scale leading to the creation of new natural aroma. Thus, this study aimed to investigate the culture conditions and optimization of the biotransformation of limonene into limonene-1,2-diol using Pestalotiopsis mangiferae LaBMicrA-505 obtained from the Brazilian Amazon. The study started with the investigation of the establishment of culture, followed by optimization of the conditions for biotransformation of R-(+)-limonene to limonene-1,2-diol, using shake flasks. The fresh biomass of P. mangiferae LaBMicrA-505 obtained in liquid media supplemented with yeast-malt extract under with 72 h (stationary phase) performed better diol productivity when compared to other biomasses. Finally, in the modeling of contour plots and surface responses of a central composite design, the use of 4 g l- 1 biomass, 2% of the substrate at 24 °C, 120 rpm, and pH of 6.0 could maximize the production of limonene-1,2-diol, accumulated up to 98.34 ± 1.53% after 96 h of reaction. This study contributed to identified operational condition for the R-(+)-limonene bioconversion scale-up. The endophytic fungus P. mangiferae LaBMicrA-505 proved to be a potent biocatalyst to biotechnologically produce limonene-1,2-diol, an aroma compounds with interesting bioactive features that up to now has been manufactured by extraction from plants with long and not environmentally friendly procedures.

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Turkish White Cheese is a brined (or pickled) cheese with a salty, acidic flavor and a soft or semi-hard texture. It is the most produced and consumed type of cheese in Turkey. The purpose of this study was to determine the non-starter lactic acid bacteria and yeast microbiota of traditionally produced Turkish White Cheese and analyze the chemical properties and the aroma profile of the cheese. The results of the study identified 27 distinct strains belonging to 14 the non-starter lactic acid bacteria species and 49 different strains belonging to 11 yeast species. Lactobacillus plantarum was found to be the dominant species among the lactic acid bacteria, while Candida zeylanoides was the dominant yeast species in the White Cheese samples. In addition, Kluyveromyces lactis and Debaryomyces hansenii were prominent yeast species in cheese samples. Turkish White Cheese samples had different aromatic properties. The study is highly significant as it anaylzed both non-starter lactic acid bacteria and yeast microbiota of traditionally produced Turkish White Cheese through molecular methods. It also determined and analyzed a number of chemical and aromatic properties of White Cheese.

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In this work, the Amazonian native acai fruit, a superfruit recognized worldwide, was used through a simple operation of maceration in alcohol vinegar to transform it into an attractive and functional product containing the acai natural colorant and its bioactive compounds. The variables studied were the proportion of alcohol vinegar to acai (8:2 and 1:1) and maceration period (7, 14, and 21 days). The final vinegar was subjected to the determination of color parameters, antioxidant capacity (DPPH, ABTS), total phenolics content (TPC), volatile compounds extracted by stir bar sorptive extraction and identified by gas-chromatography-mass spectrometry analysis. The alcohol vinegars macerated with acai presented the color according to the content of acai added and maceration period employed, whereas antioxidant capacity and TPC were comparable to vinegars elaborated from fruits and red wine. Sixty volatiles compounds classified into five chemical groups were identified. The principal volatile compounds which contributed to the aroma in the products were 3-methyl-1-butanol, phenylethyl alcohol, benzaldehyde, o-cymene, p-cymenene, isoamyl acetate, and ethyl acetate. The most attractive product regarding the parameters studied was obtained from the use of the proportion of 1:1 of alcohol vinegar:acai and maceration period of 14 days. This product retained the most similar color to acai in natura, the highest values for antioxidant capacity measured by ABTS and TPC while being rich in volatile compounds due to the contributions mainly of alcohols, esters, aldehydes, and terpenes. PRACTICAL APPLICATION: This work demonstrates the feasibility to produce an alcohol vinegar with an attractive color and functional properties by the addition of acai resulting in to a wide spectrum of chemical compounds of acai through a very simple operation of maceration during 14 days of a proportion of 1:1 of alcohol vinegar:acai.

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Cacao demand is continuously increasing, and variations in cacao prices have been associated with the aroma of fermented cacao beans. However, the role of microorganisms in the formation of volatile-aroma compounds during fermentation remains unclear. Microbial diversity in Nacional × Trinitario cacao was characterized during spontaneous fermentation by using culture-based methods and next-generation sequencing (NGS) of DNA amplicons. Cacao beans that were spontaneously fermented for 0, 24, 48, 72 and 96 h were UV-sterilized prior to the inoculation of the microbial isolates obtained by the culture-based methods. The volatile formation in inoculated cacao beans was evaluated by GC-MS. The species isolated during fermentation included yeast, such as Saccharomyces cerevisiae and Candida metapsilosis; lactic acid bacteria (LAB), such as Limosilactobacillus fermentum and Liquorilactobacillus nagelii; acetic acid bacteria (AAB), such as Acetobacter pasteurianus, Acetobacter ghanensis and Acetobacter syzygii, as well as other species, such as Bacillus subtilis and Bacillus amyloliquefaciens. Additionally, NGS revealed an abundance of environmental microorganisms, including Escherichia spp., Pantoea spp., Staphylococcus spp., Botrytis spp., Tetrapisispora spp. and Pichia spp., among others. During the lab-scale fermentation, the inoculation of S. cerevisiae mostly yielded alcohols, while LAB and AAB produced volatiles associated with floral, almond and fruity notes throughout the fermentation, but AAB also produced acetic acid with a sour aroma. Similarly, the inoculation of C. metapsilosis and Bacillus spp. in 96 h fermented cacao beans yielded esters with floral aromas. This is the first report describing the role of microorganisms in volatile formation during fine-flavor cacao fermentation.

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Since conventional thermal processing can have detrimental consequences on aroma compounds, non-thermal technologies such as high hydrostatic pressure (HHP) have been explored. HHP may alter the weak chemical bonds of enzymes. These changes can modify the secondary, tertiary, and quaternary structures of key enzymes in the production of aroma compounds. This can result in either an increase or decrease in their content, along with reactions or physical processes associated with a reduction of molecular volume. This article provides a comprehensive review of HHP treatment's effects on the content of lipid-derived aroma compounds, aldehydes, alcohols, ketones, esters, lactones, terpenes, and phenols, on various food matrices of vegetable and animal origin. The content of aldehydes and ketones in food samples increased when subjected to HHP, while the content of alcohols and phenols decreased, probably due to oxidative processes. Both ester and lactone concentrations appeared to decline due to hydrolysis reactions. There is no clear tendency regarding terpenes concentration when subjected to HHP treatments. Because of the various effects of HHP on aroma compounds, an area of opportunity arises to carry out future studies that allow optimizing and controlling the effect.

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Nine yeast strains isolated from Latin American biodiversity were screened for ferulic acid (FA) consumption and conversion into aroma compounds such as vanillin, vanillic acid (VA), and 4-vinylguaiacol (VG). Selected strains (Rhodotorula mucilaginosa UFMG-CM-Y3647, UFMG-CM-Y2190, UFMG-CM-Y665) were evaluated in flask experiments to investigate the influence of the pH media on bioconversion and a two-step process was conducted to maximize the metabolites production. The effect of pH was found to be significantly important for FA bioconversion, as acidic conditions (pH < 6.0) improved VA accumulation, with highest production of 1.14 ± 0.02 and 1.25 ± 0.03 g/L shown by UFMG-CM-Y3647 and UFMG-CM-Y2190, respectively. The two-step process favored 4-VG production for most strains, being UFMG-CM-Y2190 the best producer, its cultures reaching 1.63 ± 0.09 g/L after 55 hr, showing a productivity of 29.59 ± 1.55 mg/(L·hr), as glucose affected the metabolites pool and redirected yeast metabolism. R mucilaginosa UFMG-CM-Y3647 was selected for scaled-up cultivations in a 2-L bioreactor, where pH-controlled pH 5.5 and aeration of 2.5 vvm was found to be the best condition to improve VA productivity, attaining final concentrations of 1.20 ± 0.02 g/L-1 (78% molar yield) and a productivity of 40.82 ± 0.57 mg/(L·hr).

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The aim of this review is to describe the volatile aroma compounds of green coffee beans and evaluate sources of variation in the formation and development of coffee aroma through postharvest processing. The findings of this survey showed that the volatile constituents of green coffee beans (e.g., alcohols, aldehydes, and alkanes) have no significant influence on the final coffee aroma composition, as only a few such compounds remain in the beans after roasting. On the other hand, microbial-derived, odor-active compounds produced during removal of the fruit mucilage layer, including esters, higher alcohols, aldehydes, and ketones, can be detected in the final coffee product. Many postharvest processing including drying and storage processes could influence the levels of coffee aroma compositions, which remain to be elucidated. Better understanding of the effect of these processes on coffee aroma composition would assist coffee producers in the optimal selection of postharvest parameters that favor the consistent production of flavorful coffee beans.

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BACKGROUND: Propolis is a complex mixture that honey bees produce from the exudates of various plants and presents many medicinal properties. Its chemical composition varies according to the phytogeography characteristics of each region, among others. The aim of this study was to identify and characterize the volatile organic compounds (VOCs) present in Venezuelan propolis and compare with reference samples such as Brazilian and Argentinian propolis. RESULTS: A total of 90 VOCs were identified in a series of propolis samples using both solid-phase microextraction and dynamic headspace (DHS), both coupled to a gas chromatograph-electron ionization mass spectrometer. In the case of Venezuelan propolis, sesquiterpenes, esters, aromatic compounds, and aliphatic hydrocarbons were identified. Limonene was found only in Venezuelan samples, this being the first time it has been identified in samples from this country. In the case of green propolis, ß-caryophyllene and nerolidol were the major compounds. As for the Argentinian samples, prenyl acetate, benzyl acetate, and 2-phenylethyl acetate were detected only in these samples. CONCLUSIONS: Possible chemical markers of natural sources such as limonene were detected using DHS extraction. Several compounds have also been identified for the first time in Venezuelan propolis. Cluster analysis allowed the relating of the propolis VOCs profile to their provenance. © 2017 Society of Chemical Industry.

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This study investigates chemical information of volatile fractions of high-quality cocoa (Theobroma cacao L. Malvaceae) from different origins (Mexico, Ecuador, Venezuela, Columbia, Java, Trinidad, and Sao Tomè) produced for fine chocolate. This study explores the evolution of the entire pattern of volatiles in relation to cocoa processing (raw, roasted, steamed, and ground beans). Advanced chemical fingerprinting (e.g., combined untargeted and targeted fingerprinting) with comprehensive two-dimensional gas chromatography coupled with mass spectrometry allows advanced pattern recognition for classification, discrimination, and sensory-quality characterization. The entire data set is analyzed for 595 reliable two-dimensional peak regions, including 130 known analytes and 13 potent odorants. Multivariate analysis with unsupervised exploration (principal component analysis) and simple supervised discrimination methods (Fisher ratios and linear regression trees) reveal informative patterns of similarities and differences and identify characteristic compounds related to sample origin and manufacturing step.

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Products that bear the label "natural" have gained more attention in the marketplace. In this approach, the production of aroma compounds through biotransformation or bioconversion has been receiving more incentives in economic and research fields. Among the substrates used in these processes, terpenes can be highlighted for their versatility and low cost; some examples are limonene, α-pinene, and ß-pinene. This work focused on the biotransformation of the two bicyclic monoterpenes, α-pinene and ß-pinene; the use of different biocatalysts; the products obtained; and the conditions employed in the process.

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A pineapple vinification process was conducted through inoculated and spontaneous fermentation to develop a process suitable for a quality beverage during two successive vintages in Huambo, Angola. Wines obtained with the conventional Saccharomyces cerevisiae strain, were analysed by gas chromatography, and a total of 61 volatile constituents were detected in the volatile fraction and 18 as glycosidically bound aroma compounds. Concentration levels of carbonyl and sulphur compounds were in agreement with the limited information reported about pineapple fruits of other regions. We report, for the first time in pineapple wines, the presence of significant concentrations of lactones, ketones, terpenes, norisoprenoids and a variety of volatile phenols. Eight native yeast strains were isolated from spontaneous batches. Further single-strain fermentations allowed us to characterise their suitability for commercial fermentation. Three native strains (Hanseniaspora opuntiae, H. uvarum and Meyerozyma guilliermondii) were selected with sensory potential to ferment pineapple fruits with increased flavour diversity. Results obtained here contribute to a better understanding of quality fermentation alternatives of this tropical fruit in subtropical regions.

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In several grape varieties, the dominating aryl alkyl alcohols found are the volatile group of phenylpropanoid-related compounds, such as glycosylated benzyl and 2-phenylethyl alcohol, which contribute to wine with floral and fruity aromas after being hydrolysed during fermentation. Saccharomyces cerevisiae is largely recognized as the main agent in grape must fermentation, but yeast strains belonging to other genera, including Hanseniaspora, are known to predominate during the first stages of alcoholic fermentation. Although non-Saccharomyces yeast strains have a well-recognized genetic diversity, understanding of their impact on wine flavour richness is still emerging. In this study, 11 Hansenisapora vineae strains were used to ferment a chemically defined simil-grape fermentation medium, resembling the nutrient composition of grape juice but devoid of grape-derived secondary metabolites. GC-MS analysis was performed to determine volatile compounds in the produced wines. Our results showed that benzyl alcohol, benzyl acetate and 2-phenylethyl acetate are significantly synthesized by H. vineae strains. Levels of these compounds found in fermentations with 11 H. vineae different strains were one or two orders of magnitude higher than those measured in fermentations with a known S. cerevisiae wine strain. The implications for winemaking in response to the negative correlation of benzyl alcohol, benzyl acetate and 2-phenylethyl acetate production with yeast assimilable nitrogen concentrations are discussed. Copyright © 2016 John Wiley & Sons, Ltd.

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The aroma of strawberry and lemon guava fruits (Psidium cattleianum Sabine) was studied by sensory analysis, gas chromatography-olfactometry (GC-O) and quantitative analysis. Volatiles released from the pulps were collected in a trapping system consisting of LiChrolut EN resins and eluted with dichloromethane/methanol. In total, 23 odour zones were detected by GC-O, of which 16 were found in the extract from the strawberry guava pulp and 17 in the extract from the lemon guava pulp. Among the compounds identified, only 10 were common to both strawberry and lemon guavas. The descriptive sensorial analysis differentiated between the aroma profiles of the strawberry guava pulp with the descriptor "tomato" and the lemon guava pulp with the descriptor "tropical fruit". The typical aroma of the guava fruits was dominated by the presence of numerous aldehydes and ketones among which (Z)-3-hexenal was the most intense odorant, while 1,8-cineole and linalool were also revealed as important aroma constituents.

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Chemical profile of the Agaricus bisporus samples were analyzed using GC/MS method in ethanolic extracts. A total of 174 metabolic products were detected, which included 13 significant metabolites between 1.2 to 83 % (w/w); other 13 metabolites at 1% (w/w) and 148 metabolites less than 1% classified into 12 categories. These metabolites had many medicinal activities, which included anti-cancer, anti-cardiovascular diseases, anti-hypercholesterol, anti-microbial, hepatoprotective, human health supporting and immune enhancer. HPLC analysis of water extracts of the A. bisporus samples showed that the spores and gills in the fresh adult mushroom had higher percentage of agaritine mycotoxin than the other parts. These contents were decreased by different treatments especially by boiling, preservation and cooking. The selenium contents (ppb) was measured by Galvanometric analysis and highest content was recorded in fresh whole mushroom sample (0.97) followed by cooked preserved (0.4) and fried sample (0.11).