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1.
FEMS Yeast Res ; 21(8)2021 12 24.
Artigo em Inglês | MEDLINE | ID: mdl-34875055

RESUMO

Nowadays, biotechnological applications are emphasized to ensure sustainable development by reutilizing waste materials to prevent ecological problems and to produce or recover compounds that may have positive effects on health. Yeasts are fascinating microorganisms that play a key role in several traditional and innovative processes. Although Saccharomyces is the most important genus of yeasts, and they are major producers of biotechnological products worldwide, a variety of other yeast genera and species than Saccharomyces that are called 'non-Saccharomyces' or 'nonconventional' yeasts also have important potential for use in biotechnological applications. Some of the nonconventional yeast strains offer a unique potential for biotechnological applications to produce valuable secondary metabolites due to their characteristics of surviving and growing in such extreme conditions, e.g. wide substrate range, rapid growth, thermotolerance, etc. In this review, we aimed to summarize potential biotechnological applications of some nonconventional yeasts (Kluyveromyces spp., Yarrowia spp., Pichia spp., Candida spp., etc.) to produce industrially important aroma compounds (phenylethyl alcohol, phenylethyl acetate, isobutyl acetate, diacetyl, etc.) by reutilizing agri-food waste materials in order to prevent ecological problems and to produce or recover compounds that may have positive effects on health.


Assuntos
Eliminação de Resíduos , Saccharomyces , Yarrowia , Alimentos , Odorantes , Leveduras
2.
J Food Sci Technol ; 58(10): 3981-3992, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34471322

RESUMO

This study aimed to evaluate the performance of both near-infrared (NIR) diffuse reflectance and mid-infrared-attenuated total reflectance (MIR-ATR) in determining some quality parameters of a commercial white cheese made of unknown ratios of various milk species. For this purpose, 81 commercial Ezine cheese samples, a special ripened cheese produced in Turkey, containing unknown ratios of bovine, caprine, and ovine milk, were used. Reference analyses, including textural properties, protein content, nitrogen fractions, ripening index coefficients, fat, salt, dry matter-moisture, and ash contents as well as pH and titratable acidity levels, were conducted in the samples following the traditional gold standards. For NIR applications, the spectra of both intact cubes and hand-crushed cheese samples were collected, whereas the spectra of only hand-crushed cheese samples were collected for MIR-ATR. PLSR (Partial Least Squares Regression) calibration models were developed for each parameter (n = 61) and then validated using both cross-validation (leave-one-out approach) and an external validation set (n = 20). Overall, PLSR models developed for total protein, fat, salt, dry matter, moisture, and ash content, as well as pH and titratable acidity, yielded satisfactory performance statistics in the complementary use of NIR and MIR spectroscopy. However, PLSR models of the other parameters, including textural properties, nitrogen fractions, and the ripening index, could only separate high and low values and were not able to make accurate quantitative predictions. NIR spectroscopy was found to be more accurate than that of MIR-ATR spectroscopy for almost all the parameters except for pH and titratable acidity, for which MIR-ATR spectroscopy was superior.

3.
Yeast ; 32(1): 217-25, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25277269

RESUMO

The aim of this research was to study how the yeast cell immobilization technique influences the growth and fermentation profiles of Kluyveromyces marxianus cultivated on apple/chokeberry and apple/cranberry pomaces. Encapsulation of the cells was performed by droplet formation from a foamed alginate solution. The growth and metabolic profiles were evaluated for both free and immobilized cells. Culture media with fruit waste produced good growth of free as well as immobilized yeast cells. The fermentation profiles of K. marxianus were different with each waste material. The most varied aroma profiles were noted for immobilized yeast cultivated on apple/chokeberry pomace.


Assuntos
Frutas/metabolismo , Kluyveromyces/metabolismo , Malus/metabolismo , Prunus/metabolismo , Vaccinium macrocarpon/metabolismo , Resíduos/análise , Alginatos/química , Células Imobilizadas/química , Células Imobilizadas/metabolismo , Frutas/microbiologia , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Kluyveromyces/química , Kluyveromyces/crescimento & desenvolvimento , Malus/microbiologia , Prunus/microbiologia , Vaccinium macrocarpon/microbiologia
4.
Yeast ; 32(1): 67-76, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25308412

RESUMO

The yeast Kluyveromyces marxianus produces a range of volatile molecules with applications as fragrances or flavours. The purpose of this study was to establish how nutritional conditions influence the production of these metabolites. Four strains were grown on synthetic media, using a variety of carbon and nitrogen sources and volatile metabolites analysed using gas chromatography-mass spectrometry (GC-MS). The nitrogen source had pronounced effects on metabolite production: levels of the fusel alcohols 2-phenylethanol and isoamyl alcohol were highest when yeast extract was the nitrogen source, and ammonium had a strong repressing effect on production of 2-phenylethyl acetate. In contrast, the nitrogen source did not affect production of isoamyl acetate or ethyl acetate, indicating that more than one alcohol acetyl transferase activity is present in K. marxianus. Production of all acetate esters was low when cells were growing on lactose (as opposed to glucose or fructose), with a lower intracellular pool of acetyl CoA being one explanation for this observation. Bioinformatic and phylogenetic analysis of the known yeast alcohol acetyl transferases ATF1 and ATF2 suggests that the ancestral protein Atf2p may not be involved in synthesis of volatile acetate esters in K. marxianus, and raises interesting questions as to what other genes encode this activity in non-Saccharomyces yeasts. Identification of all the genes involved in ester synthesis will be important for development of the K. marxianus platform for flavour and fragrance production.


Assuntos
Carbono/metabolismo , Aromatizantes/metabolismo , Kluyveromyces/metabolismo , Nitrogênio/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Ésteres/metabolismo , Aromatizantes/química , Kluyveromyces/química , Kluyveromyces/classificação , Filogenia , Compostos Orgânicos Voláteis/química
5.
Yeast ; 32(1): 123-43, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25400136

RESUMO

Flavours are biologically active molecules of large commercial interest in the food, cosmetics, detergent and pharmaceutical industries. The production of flavours can take place by either extraction from plant materials, chemical synthesis, biological conversion of precursor molecules or de novo biosynthesis. The latter alternatives are gaining importance through the rapidly growing fields of systems biology and metabolic engineering, giving efficient production hosts for the so-called 'bioflavours', which are natural flavour and/or fragrance compounds obtained with cell factories or enzymatic systems. Yeasts are potential production hosts for bioflavours. In this mini-review, we give an overview of bioflavour production in yeasts from the process-engineering perspective. Two specific examples, production of 2-phenylethanol and vanillin, are used to illustrate the process challenges and strategies used.


Assuntos
Aromatizantes/metabolismo , Engenharia Metabólica , Leveduras/genética , Leveduras/metabolismo , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo
6.
Bioprocess Biosyst Eng ; 38(6): 1143-55, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25614449

RESUMO

Bioflavours are called natural flavour and/or fragrance compounds which are produced using metabolic pathway of the microorganism and/or plant cells or their enzyme systems with bioengineering approaches. The aim of this study was to investigate bioflavour production from tomato and red pepper pomaces by Kluyveromyces marxianus and Debaryomyces hansenii. Obtained specific growth rates of K. marxianus and D. hansenii in tomato pomace were 0.081/h and 0.177/h, respectively. The bioflavour profile differed between the yeasts. Both yeasts can produce esters and alcohols such as phenyl ethyl alcohol, isoamyl alcohol, isoamyl acetate, phenyl ethyl acetate and isovaleric acid. "Tarhana" and "rose" were descriptive flavour terms for tomato and pepper pomaces fermented by K. marxianus, respectively. Tomato pomace fermented by D. hansenii had the most intense "green bean" flavour while "fermented vegetable" and "storage/yeast" were defined as characteristic flavour terms for pepper pomaces fermented by D. hansenii.


Assuntos
Ascomicetos/metabolismo , Capsicum/química , Aromatizantes , Kluyveromyces/metabolismo , Solanum lycopersicum/química , Reatores Biológicos , Fermentação , Cromatografia Gasosa-Espectrometria de Massas
7.
Food Chem ; 400: 133994, 2023 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-36108443

RESUMO

Fermented Spirulina (FS) could be a good strategic approach for diversifying algae-derived formulations to a current functional food market. In this study, microbial properties, total and free amino acids, protein hydrolysis, volatile organic compounds (VOCs) and sensory properties of FS and unfermented Spirulina (unFS) products by four different Lactic acid bacteria (LAB) and three different Bacillus strains were examined. The highest proteolytic activity with LAB strains was confirmed by SDS-PAGE. The increase in both total amino acid (TAA) and total essential amino acid (TEAA) concentrations were in the highest level for FS products by Bacillus strains, 70535.5 µM and 22295.4 µM, respectively. The pyrazine content, the most prevalent VOCs in unFS, reduced more remarkably in FS by LAB strains. Furthermore, the most acceptable sensory characteristics were obtained with FS products by LAB strains. These findings will provide insights toward achieving the industrialization of FS products.


Assuntos
Lactobacillales , Spirulina , Compostos Orgânicos Voláteis , Aminoácidos/metabolismo , Aminoácidos Essenciais/metabolismo , Fermentação , Lactobacillales/metabolismo , Spirulina/metabolismo , Compostos Orgânicos Voláteis/metabolismo
8.
J Sci Food Agric ; 92(6): 1245-52, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22028053

RESUMO

BACKGROUND: Heat treatment is the most common way to extend the shelf life of milk. However, alternative technologies such as ultraviolet (UV) light and ultrasound (US), which are non-thermal methods for processing milk, have been developed to replace heat treatment. These technologies do not have any adverse effects on the quality of milk. The major purpose of this study was to investigate the effects of UV and US on different micro-organism groups and aroma compounds in milk. RESULTS: Heat pasteurisation at 65 °C for 30 min was used as thermal control treatment. The growth of total coliform group bacteria, Escherichia coli and Staphylococcus spp. was completely reduced by UV treatment. Application of US was not sufficient to reduce the numbers of yeasts and moulds. In neutral/basic fractions, 3-methylthiophene (plastic), hexanal (grass) and 1-hexen-3-one (floral) were major volatiles in milk samples. CONCLUSION: UV had a major effect on total coliforms, E. coli and Staphylococcus spp., but US was not as effective as UV and heat treatment in reducing certain groups of micro-organisms. No major differences were observed in terms of aroma-active compounds and flavour of milk following the different treatments. However, some new volatiles and change in rheological properties were generated by UV and US treatments.


Assuntos
Escherichia coli/efeitos da radiação , Microbiologia de Alimentos , Ondas de Choque de Alta Energia , Leite/efeitos da radiação , Odorantes/análise , Staphylococcus/efeitos da radiação , Raios Ultravioleta , Animais , Contagem de Colônia Microbiana , Conservação de Alimentos/métodos , Fungos/efeitos da radiação , Temperatura Alta , Humanos , Leite/microbiologia , Compostos Orgânicos Voláteis/análise , Leveduras/efeitos da radiação
9.
Arch Anim Breed ; 65(4): 385-395, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36415758

RESUMO

The use of fenugreek seed as a galactagogue has been investigated in ruminants. However, only a few studies have analyzed the effects of fenugreek seed on the milk fatty acid composition. To the authors' best knowledge, none of these studies have investigated the effects of fenugreek seed on milk volatile compounds. The objective of this study, which lasted 8 weeks, was to determine the effects of fenugreek seed supplementation on the performance, milk fatty acid profile, and milk volatile profile of goats. A total of 20 Turkish Saanen dairy goats that were mid-lactation were used in the study. This study was carried out with two homogeneous groups: the control group (CON) and fenugreek group (FG). Both groups were fed a total mixed ration (TMR), but the FG treatment had their diet supplemented with 0.1 kg d - 1 of fenugreek seed per animal. The feed intake, live weight, milk yield, milk chemical composition, serum cholesterol and triglyceride concentration, milk fatty acid profile, and milk volatile compound profile were determined. The feed intake, live weight gain, and milk yield of the goats did not significantly differ between the CON and FG treatments ( P > 0.05 ), whereas the milk fat concentration increased ( P = 0.05 ) and the serum cholesterol and triglyceride concentrations decreased ( P < 0.05 ) in the FG treatment. The unsaturated fatty acid concentration in milk ( P < 0.05 ) was also enhanced in the FG treatment. In addition, the FG treatment increased 2-propanone, 2-butanone, benzene, 1-methyl-3-(1-methylethyl), and eucalyptol concentrations in milk ( P < 0.05 ). In conclusion, the supplementation of goats' diets with fenugreek seed during the mid-lactation period did not affect their performance and improved the unsaturated fatty acid profile of their milk. Of particular importance, we have also detected an increase in the 2-propanone concentration in milk following fenugreek supplementation.

10.
Braz J Microbiol ; 53(3): 1533-1547, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35488980

RESUMO

The aim of this study was to evaluate the biosynthesis of flavor compounds from rice bran by fermentation facilitated by Kluyveromyces marxianus and Debaryomyces hansenii. The growth of both yeasts was assessed by specific growth rates and doubling time. The biosynthesis of flavor compounds was evaluated by gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS), and Spectrum™ sensory analysis. The specific growth rate (µ) and doubling time (td) of K. marxianus was calculated as 0.16/h and 4.21h, respectively, whereas that of D. hansenii was determined as 0.13/h and 5.33h, respectively. K. marxianus and D. hansenii produced significant levels of higher alcohols and acetate esters from rice bran. Results showed that K. marxianus can produce 827.27 µg/kg of isoamyl alcohol, 169.77 µg/kg of phenyl ethyl alcohol, and 216.08 µg/kg of phenyl ethyl acetate after 24-h batch fermentation. A significant amount of isovaleric acid was also synthesized by K. marxianus (4013 µg/kg) after the batch fermentation of 96 h. 415.64 µg/kg of isoamyl alcohol and 135.77 µg/kg of phenyl ethyl acetate was determined in rice bran fermented by D. hansenii after 24-h fermentation. Fermented cereals and rose were the characteristic flavor descriptors of the fermented rice bran samples. Rose flavor in fermented rice bran samples was found to be associated with phenyl ethyl alcohol, phenyl ethyl acetate, isoamyl acetate, and guaiacol. Thus, the findings of this study demonstrate that the valorization of rice bran can be achieved with the production of natural flavor compounds by yeast metabolism.


Assuntos
Debaryomyces , Kluyveromyces , Oryza , Etanol/metabolismo , Fermentação , Cromatografia Gasosa-Espectrometria de Massas , Kluyveromyces/metabolismo , Oryza/metabolismo , Leveduras/metabolismo
11.
J Biosci Bioeng ; 123(4): 451-459, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28057467

RESUMO

The aim of this study was to investigate the possibility of using tomato and red pepper pomaces for the production eight-carbon volatiles by Trichoderma atroviride and Aspergillus sojae. The fermentation of tomato and pepper pomace-based media by both moulds was conducted in shake flasks and bioreactors. Microbial growth behaviours and fermentation abilities of T. atroviride and A. sojae under both fermentation conditions were followed by microbial counting. The production of flavours from tomato and pepper pomaces by fungal metabolism was determined by gas chromatography-olfactometry, gas chromatography-mass spectrometry and sensory analysis. The results showed that T. atroviride grew faster than A. sojae, and the survival of T. atroviride in the tomato pomace was longer than that of A. sojae. However, T. atroviride grew slower than A. sojae in the pepper pomace. Eight-carbon flavour compounds, including (Z)-1,5-octadien-3-ol, 1-octen-3-ol, (E)-2-octenal and (E)-2-octenol, were produced by T. atroviride and A. sojae from the tomato and pepper pomaces. The highest production levels (265.55 ± 2.79 and 187.47 ± 0.92 µg kg-1) were observed for 1-octen-3-ol in the tomato fermentation by T. atroviride and A. sojae, respectively. The relationships between volatile compounds and their flavour characteristics in tomato and pepper pomaces were analysed using principal component analysis.


Assuntos
Aspergillus/metabolismo , Reatores Biológicos , Carbono/química , Carbono/metabolismo , Aromatizantes/metabolismo , Piper nigrum/química , Solanum lycopersicum/química , Trichoderma/metabolismo , Aspergillus/crescimento & desenvolvimento , Fermentação , Aromatizantes/química , Cromatografia Gasosa-Espectrometria de Massas , Octanóis/química , Octanóis/metabolismo , Análise de Componente Principal , Paladar , Trichoderma/crescimento & desenvolvimento , Verduras/química
12.
Nat Prod Res ; 31(18): 2169-2173, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28067067

RESUMO

Cinclidotus fontinaloides (Hedw.) P. Beauv. and Palustriella commutata (Hedw.) Ochyra were used in this study. The chemical composition of mosses in the ethanol and water extract was determined using GC-MS and FT-IR. Antioxidant activities of moss extracts were tested by total phenol and ABTS methods. Trolox equivalent value (TEAC) of mosses was calculated as 26 ± 0.32 and 10 ± 0.22 mg/g. The amounts of the flavonoid compounds were calculated as mg gallic acid. Gallic acid equivalent value of mosses was calculated as 587 ± 0.55 and 496 ± 0.22 mg/g. The extracts antimicrobial activity was tested against Escherichia coli (ATCC 8739), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 10145) and Candida albicans (ATCC 10231). Significant antibacterial effect was observed for C. fontinaloides and P. commutata in ethanol extract. Total anthocyanin activities of C. fontinaloides and P. commutata were determined as 50 ± 0.17 and 144 ± 0.33 mg/L.


Assuntos
Antocianinas/farmacologia , Anti-Infecciosos/farmacologia , Antioxidantes/farmacologia , Briófitas/química , Antocianinas/química , Antibacterianos/química , Antibacterianos/farmacologia , Anti-Infecciosos/química , Antioxidantes/química , Candida albicans/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Flavonoides/análise , Ácido Gálico/análise , Cromatografia Gasosa-Espectrometria de Massas , Testes de Sensibilidade Microbiana , Extratos Vegetais/análise , Extratos Vegetais/química , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus/efeitos dos fármacos , Turquia
13.
Braz J Microbiol ; 48(2): 275-285, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28017541

RESUMO

The purpose of this study was to investigate the production of flavor compounds from olive mill waste by microbial fermentation of Rhizopus oryzae and Candida tropicalis. Olive mill waste fermentations were performed in shake and bioreactor cultures. Production of flavor compounds from olive mill waste was followed by Gas Chromatography-Mass spectrometry, Gas chromatography- olfactometry and Spectrum Sensory Analysis®. As a result, 1.73-log and 3.23-log cfu/mL increases were observed in the microbial populations of R. oryzae and C. tropicalis during shake cultures, respectively. C. tropicalis can produce a higher concentration of d-limonene from olive mill waste than R. oryzae in shake cultures. The concentration of d-limonene was determined as 185.56 and 249.54µg/kg in the fermented olive mill waste by R. oryzae and C. tropicalis in shake cultures respectively. In contrast, R. oryzae can produce a higher concentration of d-limonene (87.73µg/kg) d-limonene than C. tropicalis (11.95µg/kg) in bioreactor cultures. Based on sensory analysis, unripe olive, wet towel, sweet aromatic, fermented aromas were determined at high intensity in olive mill waste fermented with R. oryzae meanwhile olive mill waste fermented with C. tropicalis had only a high intensity of unripe olive and oily aroma.


Assuntos
Candida tropicalis/metabolismo , Aromatizantes/metabolismo , Resíduos Industriais , Olea/metabolismo , Rhizopus/metabolismo , Biotecnologia/métodos , Contagem de Colônia Microbiana , Cicloexenos/metabolismo , Fermentação , Cromatografia Gasosa-Espectrometria de Massas , Limoneno , Olfatometria , Terpenos/metabolismo
14.
Food Sci Biotechnol ; 25(6): 1633-1637, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-30263455

RESUMO

In this research, the antagonistic effects of Enterococcus faecalis and E. faecium bacteria isolated from naturally fermented Turkish white cheeses, produced without starter culture, against Listeria monocytogenes, L. innocua, L. ivanovii, Staphylococcus aureus, and E. faecalis were evaluated. The presence of entA and entB genes was also detected in the isolates, which had antimicrobial activity. Total 71 strains of E. faecalis and 7 strains of E. faecium were tested; 20 of E. faecalis and none of E. faecium strains showed antimicrobial activity against the tested bacteria using agar spot method. Among E. faecalis strains, which had antimicrobial activity, three strains contained both entA and entB genes, two strains carried only entA gene, and five strains had only entB gene. These cheese-sourced enterococcal strains or their enterocins should be considered to be used for food preservation especially in the dairy industry.

15.
Braz J Microbiol ; 47(4): 965-972, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27515464

RESUMO

The aim of this study was to evaluate the effects of alginate entrapment on fermentation metabolites of Kluyveromyces marxianus grown in agrowastes that served as the liquid culture media. K. marxianus cells entrapped in Na-alginate were prepared using the traditional liquid-droplet-forming method. Whey and pomaces from processed tomatoes, peppers, and grapes were used as the culture media. The changes in the concentrations of sugar, alcohol, organic acids, and flavor compounds were analyzed using gas chromatography-mass spectrometry (GC-MS) and high pressure liquid chromatography (HPLC). Both free and entrapped, K. marxianus were used individually to metabolize sugars, organic acids, alcohols, and flavor compounds in the tomato, pepper, grape, and acid whey based media. Marked changes in the fermentation behaviors of entrapped and free K. marxianus were observed in each culture. A 1.45-log increase was observed in the cell numbers of free K. marxianus during fermentation. On the contrary, the cell numbers of entrapped K. marxianus remained the same. Both free and entrapped K. marxianus brought about the fermentation of sugars such as glucose, fructose, and lactose in the agrowaste cultures. The highest volume of ethanol was produced by K. marxianus in the whey based media. The concentrations of flavor compounds such as ethyl acetate, isoamyl alcohol, isoamyl acetate, 2-phenylethyl isobutyrate, phenylethyl acetate, and phenylethyl alcohol were higher in fermented agrowaste based media compared to the control.


Assuntos
Alginatos/metabolismo , Fermentação , Kluyveromyces/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Resíduos , Biodegradação Ambiental , Ácido Glucurônico/metabolismo , Ácidos Hexurônicos/metabolismo , Resíduos Industriais
16.
J Food Sci ; 80(9): S2035-44, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26259923

RESUMO

The purpose of this study was to determine the physicochemical, thermal and sensorial features of vitamin enriched and aromatized hazelnut oil-beeswax and sunflower wax organogels. Another objective was to monitor the influence of storage on textural and oxidative stability and volatile composition of the organogels. The results show that organogels with beeswax had lower levels of solid fat content, melting point and firmness than sunflower wax counterparts. The microphotographs revealed that beeswax organogels had spherical crystals while sunflower wax organogels continued need-like crystals, but both organogels continued crystallized ß' polymorph. All organogels maintained their oxidative stability during storage. Quantitative descriptive analysis results were consistent with these findings that the organogel structure and properties were similar to breakfast margarine. The main volatile components of the organogels with added strawberry aroma were ethyl acetate, ethyl butanoate, ethyl-2-methyl butanoate, D-limonene, ethyl caproate; banana-aroma were isoamyl acetate, isoamyl valerianate, ethyl acetate; and butter-aroma were 2,3-butanedione, 3-hydroxy-2-butanone. These volatile components were not only detected in the fresh samples but also at the end of the storage period. Sensory definition terms were matched with the sensory descriptors of the detected volatiles. In conclusion, the new organogels were shown to be suitable for food product applications.


Assuntos
Corylus/química , Substitutos da Gordura/análise , Helianthus/química , Odorantes/análise , Óleos de Plantas/química , Compostos Orgânicos Voláteis/análise , Ceras/química , Acetoína/análise , Adulto , Cicloexenos/análise , Diacetil/análise , Gorduras Insaturadas na Dieta/análise , Ácidos Graxos/análise , Feminino , Alimentos Fortificados/análise , Géis , Humanos , Limoneno , Margarina , Oxirredução , Paladar , Terpenos/análise , Vitaminas
17.
J Agric Food Chem ; 50(2): 305-12, 2002 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-11782199

RESUMO

Nonfat dry milk (NDM) is widely used both as an ingredient in other preparations and for direct consumption. Flavor quality of NDM is a critical parameter because it can directly impact final product quality. Flavors can be formed in NDM during subsequent storage. Identification of compounds responsible for storage-induced flavors is necessary to correlate sensory quality with potential sources of the flavors. Six NDM samples were selected for volatile flavor analysis based on sensory analysis and storage time. Volatile components were extracted by direct solvent extraction/high vacuum distillation. Volatile extracts were separated into neutral/basic and acidic fractions and analyzed by gas chromatography-olfactometry (GCO) and aroma extract dilution analysis (AEDA). A variety of aldehydes, ketones, and free fatty acids were responsible for generation of flavors in stored NDM. The following compounds exhibited high aroma impact by AEDA: 3-(methylthio)propanal (boiled potato); o-aminoacetophenone (corn tortilla); 2,5-dimethyl-4-hydroxy-3(2H)-furanone and 2-methyl-3-hydroxy-4H-pyran-4-one (burnt sugar); butanoic acid (cheesy); pentanoic acid (sweaty); acetic and hexanoic acids (sour/vinegar); octanoic, decanoic, and dodecanoic acids (waxy); p-cresol (cowy/barny); 3-methylindole (fecal); dimethyl trisulfide (cabbage); (E,E)-2,4-decadienal (fried/fatty); furfuryl alcohol (rubber/vitamin); phenylacetic acid (rose-like); and 1-octen-3-one (mushroom).


Assuntos
Cromatografia Gasosa/métodos , Leite/química , Paladar , Animais , Manipulação de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Volatilização
18.
J Agric Food Chem ; 51(23): 6797-801, 2003 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-14582977

RESUMO

Rennet casein, produced by enzymatic (rennet) precipitation of casein from pasteurized skim milk, is used in both industrial (technical) and food applications. The flavor of rennet casein powder is an important quality parameter; however, the product often contains an odor described as like that of animal/wet dog. Two commercial rennet casein powders were evaluated to determine the compounds responsible for the typical odor. Aroma extracts were prepared by high-vacuum distillation of direct solvent (ether) extracts and analyzed by gas chromatography-olfactometry (GCO), aroma extract dilution analysis (AEDA), and GC-mass spectrometry (MS). Odorants detected by GCO were typical of those previously reported in skim milk powders and consisted mainly of short-chain volatile acids, phenolic compounds, lactones, and furanones. Results of AEDA indicated o-aminoacetophenone to be a potent odorant; however, sensory descriptive sensory analysis of model aroma systems revealed that the typical odor of rennet casein was principally caused by hexanoic acid, indole, guaiacol, and p-cresol.


Assuntos
Caseínas/química , Quimosina/química , Odorantes/análise , Animais , Cromatografia Gasosa , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Lactonas/análise , Leite/química , Fenóis/análise , Olfato , Volatilização
19.
Braz. j. microbiol ; 48(2): 275-285, April.-June 2017. tab, graf
Artigo em Inglês | LILACS | ID: biblio-839373

RESUMO

Abstract The purpose of this study was to investigate the production of flavor compounds from olive mill waste by microbial fermentation of Rhizopus oryzae and Candida tropicalis. Olive mill waste fermentations were performed in shake and bioreactor cultures. Production of flavor compounds from olive mill waste was followed by Gas Chromatography–Mass spectrometry, Gas chromatography- olfactometry and Spectrum Sensory Analysis ®. As a result, 1.73-log and 3.23-log cfu/mL increases were observed in the microbial populations of R. oryzae and C. tropicalis during shake cultures, respectively. C. tropicalis can produce a higher concentration of d-limonene from olive mill waste than R. oryzae in shake cultures. The concentration of d-limonene was determined as 185.56 and 249.54 µg/kg in the fermented olive mill waste by R. oryzae and C. tropicalis in shake cultures respectively. In contrast, R. oryzae can produce a higher concentration of d-limonene (87.73 µg/kg) d-limonene than C. tropicalis (11.95 µg/kg) in bioreactor cultures. Based on sensory analysis, unripe olive, wet towel, sweet aromatic, fermented aromas were determined at high intensity in olive mill waste fermented with R. oryzae meanwhile olive mill waste fermented with C. tropicalis had only a high intensity of unripe olive and oily aroma.


Assuntos
Rhizopus/metabolismo , Candida tropicalis/metabolismo , Olea/metabolismo , Aromatizantes/metabolismo , Resíduos Industriais , Terpenos/metabolismo , Biotecnologia/métodos , Contagem de Colônia Microbiana , Cicloexenos/metabolismo , Fermentação , Olfatometria , Cromatografia Gasosa-Espectrometria de Massas
20.
Braz. j. microbiol ; 47(4): 965-972, Oct.-Dec. 2016. tab
Artigo em Inglês | LILACS | ID: biblio-828203

RESUMO

Abstract The aim of this study was to evaluate the effects of alginate entrapment on fermentation metabolites of Kluyveromyces marxianus grown in agrowastes that served as the liquid culture media. K. marxianus cells entrapped in Na-alginate were prepared using the traditional liquid-droplet-forming method. Whey and pomaces from processed tomatoes, peppers, and grapes were used as the culture media. The changes in the concentrations of sugar, alcohol, organic acids, and flavor compounds were analyzed using gas chromatography-mass spectrometry (GC-MS) and high pressure liquid chromatography (HPLC). Both free and entrapped, K. marxianus were used individually to metabolize sugars, organic acids, alcohols, and flavor compounds in the tomato, pepper, grape, and acid whey based media. Marked changes in the fermentation behaviors of entrapped and free K. marxianus were observed in each culture. A 1.45-log increase was observed in the cell numbers of free K. marxianus during fermentation. On the contrary, the cell numbers of entrapped K. marxianus remained the same. Both free and entrapped K. marxianus brought about the fermentation of sugars such as glucose, fructose, and lactose in the agrowaste cultures. The highest volume of ethanol was produced by K. marxianus in the whey based media. The concentrations of flavor compounds such as ethyl acetate, isoamyl alcohol, isoamyl acetate, 2-phenylethyl isobutyrate, phenylethyl acetate, and phenylethyl alcohol were higher in fermented agrowaste based media compared to the control.


Assuntos
Resíduos , Kluyveromyces/metabolismo , Alginatos/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Fermentação , Biodegradação Ambiental , Ácido Glucurônico/metabolismo , Ácidos Hexurônicos/metabolismo , Resíduos Industriais
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