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Screening and characterisation of wine related enzymes produced by wine associated lactic acid bacteriaMtshali, Phillip Senzo 03 1900 (has links)
Thesis (Msc (Viticulture and Oenology))--University of Stellenbosch, 2007. / Among the factors contributing to wine complexity and quality, wine aroma is one of the
most important factors. Wine aroma is the outcome of interaction among different
compounds produced from the grapes, during fermentation as well as during the ageing
process. Apart from its origin from grapes, fungi and yeasts, wine aroma can also be
derived from the metabolic activity of wine lactic acid bacteria (LAB). These
microorganisms are usually associated with malolactic fermentation (MLF) which normally
occurs after alcoholic fermentation. MLF is beneficial to wine due to its contribution to
deacidification, microbiological stabilisation and wine aroma formation, with the latter being
the most important area of interest in our study. The production of volatile aromatic
components in wine can, in part, be achieved through the hydrolytic action of enzymes
produced by LAB associated with wine. These enzymes include β-glucosidase, protease,
esterase, lipase and glucanase. Most of the work done on bacterial enzymes has been on
LAB from food sources other than wine, in which these enzymes contribute to the flavour
development of some cheeses, yoghurt and other fermented foods. The activity of these
enzymes during wine fermentation has mostly been concerned with β-glucosidase from
Oenococcus oeni. Only in recent years has there been a renewed interest in evaluating
the activity of β-glucosidase in other genera of wine LAB.
The overriding goal of this study was to screen and characterise wine-related enzymes
produced by LAB associated with wine. All the LAB isolates tested in this study were
obtained from IWBT culture collection and were previously isolated from five different
wineries situated in the Western Cape region, South Africa. We first screened isolates
using classical methods. The isolates were grown on agar medium supplemented with
appropriate substrate analogues in order to evaluate the activity of enzymes (i.e. β-
glucosidase, glucanase, lipase and esterase). The colonies exhibiting enzymatic activity ...
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Authentication of Sauvignon blanc wine in terms of added flavouringsTreurnicht, Jeanne 03 1900 (has links)
Thesis (MSc (Wine Biotechnology))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: The varietal character of Sauvignon blanc wine is mostly defined by the balance between
tropical and green vegetative flavour nuances. Grape derived methoxypyrazines are the main
aroma contributors towards green vegetative flavours. Methoxypyrazines are heat and light
sensitive. Due to warm climatic conditions in South Africa, methoxypyrazine levels decrease
during grape ripening.
The addition of food flavourings to Sauvignon blanc wine, a practice known as spiking, has
occurred in the past to improve the green character of the wines. Adding flavourings to wine and
selling the wine as natural certified wine is illegal in South Africa. Currently, adulterated
Sauvignon blanc wines are identified using gas chromatography–mass spectrometry (GC-MS)
and liquid chromatography–mass spectrometry (LC-MS) methods to quantify methoxypyrazines
and compare levels to an established database. Although of high sensitivity, GC-MS and LCMS methods are costly and time consuming, therefore not optimal for routine screening of
wines. Hence the need for the development of a fast and cost effective method for routine
screening of large amounts of wines to identify adulteration.
Small scale vinification practices were used to prepare experimental Sauvignon blanc wine.
Flavourings were added to Sauvignon blanc grape juice before fermentation, during the
preparation of experimental spiked wines. Control wines, containing no flavouring, were also
prepared. Commercial wines were spiked after fermentation and bottling. Each wine was only
spiked with a single flavouring. The flavourings added were the juice of homogenised fresh
green peppers and commercially available flavourings for wine. The following commercial
flavourings were used: green pepper, asparagus, grassy and tropical.
The above mentioned wines were analyzed using Fourier transform infrared (FT-IR)
spectroscopy, GC-MS, LC-MS and descriptive sensory analysis. The FT-IR techniques used
were Fourier transform mid infrared (FT-MIR) transmission, FT-MIR attenuated reflection and
Fourier transform near infrared (FT-NIR) reflection spectroscopy. The data was interpreted
using the following multivariate statistical techniques: principal component analysis (PCA),
partial least squares discrimination (PLS-D) and conformity testing.
Multivariate models constructed from FT-MIR and FT-NIR data were able to discriminate
between spiked and control wines. Sensory analysis results clearly showed differences between
non-spiked wines and spiked wines with 3-isobutyl-2-methoxypyrazine concentrations 10 times
higher than naturally occurring in wine. Differences between control and spiked wines with
concentrations of 3-isobutyl-2-methoxypyrazine similar to concentrations naturally occurring in
wines could not be detected to prove adulteration conducting sensory analysis. However,
differences between control and spiked wines with levels of 3-isobutyl-2-methoxypyrazine
similar to levels naturally occurring in wines could be detected using FT-IR data in conjunction
with multivariate statistics.
This study showed that, FT-IR spectroscopy in conjunction with multivariate statistical methods
can be a possibility for the screening and identification of wines suspected of adulteration in
terms of added flavourings. Descriptive sensory analysis also proved to be a potentially useful
tool. However screening and training of potential panel members are time consuming. / AFRIKAANSE OPSOMMING: Die variëteitskarakter van Sauvignon blanc wyn word grotendeels gedefinieer deur die balans
tussen tropiese en groen vegetatiewe aromas. Metoksipirasiene is die hoof aroma verbindings
wat verantwoordelik is vir groen vegetatiewe aromas. Metoksipirasien is hitte- en ligsensitief.
Warm klimaatsomstandighede in Suid-Afrika het tot gevolg dat metoksipirasien konsentrasies
daal tydens druif rypwording.
Sauvignon blanc wyne is in die verlede vervals deur middel van die byvoeging van vars groen
soetrissies om die groen vegetatiewe karaktereienskappe van die wyne te bevorder. Die
byvoeging van geurmiddels of plantekstrakte by wyn en verkoop van daardie wyn as
gesertifiseerde natuurlike wyn is onwettig in Suid-Afrika. Tans word vervalsde wyne met behulp
van gaschromatografie-massaspektrometrie (GC-MS) en vloeistofchromatografie-massaspektrometrie (LC-MS) opgespoor. Kwantifisering van metoksiepirasien konsentrasies in wyne
en druiwesappe word vergelyk met konsentrasies in ‘n bestaande databasis. Alhoewel GC-MS
en LC-MS hoë sensitiwiteitsmetodes is, is dit duur en tydrowende metodes, dus nie optimaal vir
roetine sifting nie. Dus word ‘n koste- en tydseffektiewe roetine metode benodig om vervalsing
van wyne op te spoor.
Eksperimentele wyne is op klein skaal berei. Geurmiddels is voor fermentasie by die druiwesap
gevoeg. Kontrole wyne waarby geen geurmiddels gevoeg is nie, is ook berei. Kommersiële
wyne is gegeur na fermentasie en bottelering. Elke wyn is met ‘n enkele geurmiddel gegeur.
Gehomogeniseerde vars groen soetrissie asook kommersieel beskikbare geursels vir wyn is
gebruik. Die volgende kommersiële geursels is gebruik: groen soetrissie, aspersie, gras en
tropiese geursel.
Die volgende analitiese tegnieke is gebruik vir analisering van bogenoemde wyne: Fourier
transformasie infrarooi (FT-IR) spektroskopie, GC-MS, LC-MS en beskrywende sensoriese
analise. Die spesifieke FT-IR tegnieke wat gebruik is, is: Fourier transformasie mid-infrarooi
(FT-MIR) transmissie, FT-MIR verswakte weerskaatsing en Fourier transformasie naby-infrarooi
(FT-NIR) reflektansie. Die volgende multiveranderlike statistiese tegnieke is gebruik ter
interpretasie van data: hoof komponent analise (PCA), parsiële kleinste kwadraat diskriminant
analise (PLS-D) en gelykvormigheidstoetsing.
Multiveranderlike modelle, bereken met behulp van FT-MIR en FT-NIR data, kon diskrimineer
tussen gegeurde en kontrole wyne. Resultate wat verkry is tydens sensoriese analises het
duidelike verskille uitgewys tussen gegeurde en kontrole wyne met betrekking tot 3-isobutiel-2-
metoksipirasien konsetrasies waar 3-isobutiel-2-metoksipirasien konsentrasies 10 keer hoër
was as wat natuurlik voorkom in wyn. Geen beduidende verskille kon waargeneem word in
gevalle waar wyne vervals is met laer konsentrasies van geurmiddels deur sensoriese data te
ontleed nie. Nietemin, statisitiese verskille tussen kontrole en vervalsde wyne kon waargeneem
word vir lae-konsentrasie-geurmiddel vervalsde wyne deur FT-IR data met behulp van
multiveranderlike statisitiese metodes te ontleed.
Hierdie studie het gewys dat FT-IR in kombinasie met multiveranderlike statistiese tegnieke
spesifiek hoof komponent analise (PCA) en parsiële kleinste kwadraat diskriminant analise
(PLS-D) asook gelykvormigheidstoetsing bruikbare tegnieke is om te onderskei tussen kontrole
(egte natuurlike) en vervalsde wyne ten opsigte van die byvoeging van geurmiddels.
Beskrywende sensoriese analise kan ook nuttig gebruik word, alhoewel keuring en opleiding
van paneellede tydrowend is.
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Heavy Flavor Dynamics in Relativistic Heavy-ion CollisionsCao, Shanshan January 2014 (has links)
<p>Heavy flavor hadrons serve as valuable probes of the transport properties of the quark-gluon plasma (QGP) created in relativistic heavy-ion collisions. In this dissertation, we introduce a comprehensive framework that describes the full-time evolution of heavy flavor in heavy-ion collisions, including its initial production, in-medium evolution inside the QGP matter, hadronization process from heavy quarks to their respective mesonic bound states and the subsequent interactions between heavy mesons and the hadron gas.</p><p>The in-medium energy loss of heavy quarks is studied within the framework of a Langevin equation coupled to hydrodynamic models that simulate the space-time evolution of the hot and dense QGP matter. We improve the classical Langevin approach such that, apart from quasi-elastic scatterings between heavy quarks and the medium background, radiative energy loss is incorporated as well by treating gluon radiation as a recoil force term. The subsequent hadronization of emitted heavy quarks is simulated via a hybrid fragmentation plus recombination model. The propagation of produced heavy mesons in the hadronic phase is described using the ultra-relativistic quantum molecular dynamics (UrQMD) model. Our calculation shows that while collisional energy loss dominates the heavy quark motion inside the QGP in the low transverse momentum (pT) regime, contributions from gluon radiation are found to be significant at high pT. The recombination mechanism is important for the heavy flavor meson production at intermediate energies. The hadronic final state interactions further enhance the suppression and the collective flow of heavy mesons we observe. Within our newly developed framework, we present numerical results for the nuclear modification and the elliptic flow of D mesons, which are consistent with measurements at both the CERN Large Hadron Collider (LHC) and the BNL Relativistic Heavy-Ion Collider (RHIC); predictions for B mesons are also provided.</p><p>In addition, various transport properties of heavy quarks are investigated within our numerical framework, such as the thermalization process of heavy quarks inside the QGP, and how the initial configuration of the QGP as well as its properties affect the final state spectra and the elliptic flow of heavy mesons and their decay electrons. The effects of initial state fluctuations in heavy-ion collisions are also studied and found to enhance the heavy quark energy loss in a (2+1)-dimensional boost invariant scenario. Furthermore, a new set of observables -- heavy-flavor-tagged angular correlation functions -- are explored and found to be potential candidates for distinguishing different energy loss mechanisms of heavy quarks inside the QGP.</p> / Dissertation
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Etude des transferts d'arômes encapsulés dans une matrice alimentaire type génoise / Study of encapsulated flavours transfers in food matrix like sponge cakeMadene, Atmane 14 November 2006 (has links)
Ces travaux portent sur l’étude du transfert de l’arôme viennoiserie encapsulé dans une matrice constituée du mélange gomme acacia – maltodextrines et incorporé dans une génoise emballée (plastiques et papier), dans des conditions contrôlées de stockage (humidité relative et température). Le procédé d’encapsulation utilisé dans cette étude est la lyophilisation. Les propriétés physicochimiques des molécules volatiles influencent leur rétention. Ainsi, les molécules hydrophobes à haut poids moléculaire sont mieux conservées dans ce système. L’incorporation de capsules d’arômes dans les génoises influence leurs propriétés physiques (la couleur et la texture) et favorise la formation d’une croûte pouvant jouer un rôle barrière sur les transferts d’arômes. Au cours du stockage des génoises emballées, l’apport positif de l’encapsulation sur la rétention des arômes a été révélé. Le type d’emballage peut influencer la perte en composés d’arôme dans l’espace de tête génoise – emballage. Ainsi, les emballages plastiques offrent une meilleure conservation des molécules volatiles par rapport aux papiers traités / This study deals with transfer of viennoiserie aroma encapsulated in a acacia gum - maltodextrines matrix and incorporated in a packaged sponge cake (plastic and treated-paper), under controlled storage conditions (temperature and relative humidity). The process of encapsulation used in this work is freeze-drying. The physicochemical properties of the volatiles molecules influence their retention in the matrix. Thus, the hydrophobic molecules with high molecular weight are more retained. The incorporation of capsules in the sponge cake matrix influences the physical properties of food matrix (color and texture) and supports the formation of a crust which acts as a barrier in the flavour transfer. It was noted that encapsulation contributed in retaining flavour compounds during the storage of packaged sponge cake. Also, the type of packaging can influence the loss of flavour in the headspace between sponge cake and packaging. Indeed, plastic packaging offers a better conservation of volatiles molecules compared to treated-papers
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[en] SEARCH FOR STERILE NEUTRINOS BY EXPERIMENTS AT NUCLEAR REACTORS / [pt] PROCURA POR NEUTRINOS ESTÉREIS ATRAVÉS DE EXPERIMENTOS COM REATORES NUCLEARESANDERSON JOSE DA FONSECA 30 October 2006 (has links)
[pt] Nesse trabalho realizamos, em princípio, um estudo
fenomenológico de alguns experimentos prévios com
neutrinos, que utilizaram reatores nucleares como fonte.
Tais experimentos buscaram evidências de distorção
espectral que corroborassem o mecanismo de conversão de
sabor entre neutrinos. Nessa etapa reunimos suficiente
informação sobre a metodologia empregada para a detecção e
análise do espectro de neutrinos de reatores, bem como os
limites impostos por esses experimentos sobre os
parâmetros de oscilação. A partir desse estudo,
investigamos a possibilidade de se explorar uma região do
espaço de parâmetros, caracterizada por um pequeno ângulo
de mistura e elevado autoestado de massa, ainda não
excluída pelos resultados experimentais atuais. Como uma
escala de massa tão elevada não pode estar associada a
qualquer um dos três sabores ativos (eletrônico, muônico
ou tauônico), em nossa análise, utilizamos uma extensão do
modelo de três neutrinos ativos, incorporando um quarto
autoestado estéril. Por fim, discutimos uma configuração
experimental, baseada em um reator nuclear, que apresente
a sensibilidade necessária para atingir esse conjunto de
parâmetros. / [en] In this dissertation we have done, at first, a
phenomenological study
of some previous neutrino experiments, that had searched
evidences of
spectral distortion that corroborated the mechanism of
flavor conversion,
using nuclear reactors as source. We collected enough
information about
the methodology used for detection and analisys of
neutrino spectrum of
reactors, as well as the constraints on oscillation
parameters provided by
that experiments. Starting from this study, we
investigated the possibility
to explore a region of the space of parameters,
characterized by a small
mixing angle and high mass eigenstate, that not yet have
been excluded
by experimental results, but incompatible with the
extracted current mass
scale of the experiments with solar, atmospheric,
accelerator (except for
the LSND experiment) and reactor neutrinos. For this
inquiry, we assume
the simplest extension of the standart oscillation model,
incorporating a
new eigenstate responsible for the higher scale mass.
Finally, we discuss a
experimental configuration, based on nuclear reactor,
which presents the
sensitivity required to reach this set of parameters.
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Search for B → π τ ν with hadronic tagging at BelleHamer, Philipp 09 November 2015 (has links)
Eine Suche nach dem Zerfall B → π τ ν wird vorgestellt. Die Suche wird auf dem vollständigen Belle Datensatz durchgeführt, der 772E6 B anti-B Paare beinhaltet, die auf der Y(4s) Resonanz mit Belle Detektor am asymmetrischen e+e- KEKB Beschleuniger gesammelt wurden. Das τ Lepton wird in den Zerfallskanälen τ → e ν ν, τ → μ ν ν, τ → π ν und τ → ρ ν rekonstruiert. Eines der beiden B Mesonen, das Btag, wird mittels eines auf NeuroBayes beruhenden Algorithmus vollständig in einem hadronischen Zerfallskanal rekonstruiert. Der Rest des Kollisionsereignisses beinhaltet genau zwei geladene Spuren im Falle eines Signalzerfalls. Die weitere Trennung zwischen Signal und Untergrund wird mithilfe von Boosted Decision Trees durchgeführt. Ein Fit wird in der Verteilung der Extra Energie im elektromagnetischen Kalorimeter ECL, welche definiert ist als alle Energie die weder vom Btag noch von der rekonstruierten Signalseite stammt, durchgeführt. Kein signifikantes Signal wird beobachtet und ein oberes Limit von Br( B → π τ ν ) < 2.5E-4 basierend auf einem Vertrauensintervall von 90% wird bestimmt. Das Ergebnis ist in guter Übereinstimmung mit der Vorhersage des Standard Modells.
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The Standard Model Analyasis Of The Cp Violation In The Inclusive Semileptonic B-meson DecaysEygi, Zeynep Deniz 01 February 2005 (has links) (PDF)
Being a flavor changing neutral current process, inclusive semileptonic B- meson decays provide reliable testing grounds for the Standard Model at the loop level. They are also importanat in the CKM phenomology and investing the CP violation due to the existence of sizable interference terms in the decay amplitude. In this work , the rare inclusive semileptonic B- meson decays for (lepton is electron ,muon , tau) are investigated in the context of the Standard Model.The differential branching ratio, forward-backward asymmetry ,CP &ndash / violating asymmetry and CP &ndash / violating asymmetry in the forward-backward asymmetry in these processes are examined.The dependencies of these physical parameters on the Standard Model parametres are analyzed by paying a special attention to the long distance effects. Although the branching ratios predicted for the inclusive semileptonic B- meson decays are relatively small because of CKM suppression , it has been found that there is a significant ACP and ACP(AFB) for these processes.
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Chemical, sensory and consumer analysis of cork taint in South African winesVan Eeden, Petrus Rabe 03 1900 (has links)
Thesis (MSc Food Sc (Food Science))--University of Stellenbosch, 2009. / This study focused on a serious quality-related problem in the global wine industry, including
the South African Wine Industry, namely cork taint in wine. Annually, large financial losses
are incurred by cork suppliers and wine producers, as a result of cork-tainted wine. Although
contaminated new unused corks are frequently implicated as the origin of this taint,
contaminated cellar equipment and water can also be the source of the problem.
An explorative investigation into the incidence of cork taint in South African wines showed
that 3.8% of the 133 wines tested, contained 2,4,6-trichloroanisole (TCA) concentrations of
3.5 ng/L and higher, as determined by gas chromatography coupled with electron capture
detection (GC-ECD). TCA concentrations higher than 1 ng/L were found in 18% of the wines
tested. All affected wines were sealed with solid or agglomerate cork stoppers. These wines
were sourced from various wineries in the Western Cape region, South Africa and were of
different cultivars. None of the wines sealed with synthetic closures had any detectable TCA,
2,4,6-tribromoanisole (TBA) or pentachloroanisole (PCA) levels and only very low 2,3,4,6-
tetrachloroanisole (TeCA) levels (1 ng/L or less). Another group of 28 wines that were
rejected by the official South African wine regulatory body on the basis of the presence of
mouldy taint during wine certification, was also included in this study. GC-ECD analysis
showed that 30% of the wines in this group contained TCA at concentrations of 3.5 ng/L and
higher. These results pointed to a relative high incidence of TCA in the wines investigated,
especially those sealed with cork stoppers. Although no general conclusions should be made
on the incidence of cork taint in the wider wine industry based on the results found within this
explorative investigation, these findings confirmed the presence of cork taint in South African
wines.
Detection threshold values were determined for TCA, TeCA, TBA and PCA in three wine
cultivars using the standard ASTM method. Results indicate that factors relating to the wine
cultivar seemed to affect threshold values considerably. Our research proposes a detection
range rather than an average detection threshold. Detection ranges established for TCA,
TeCA, TBA and PCA in Chenin blanc, Pinotage and Shiraz coincide with reported values in
literature. This result can be regarded as a valuable expansion of the existing knowledge of
detection threshold values.
Descriptive sensory analysis indicated significant (P 0.05) changes in the aroma profile of
Chenin blanc, Pinotage and Shiraz after TCA, TeCA, TBA or PCA was added to the respective base wines that contained no detectable levels of the haloanisoles. The mouldy
taint induced by these haloanisoles were described as mouldy, mouldy-chemical, mouldychlorine,
as well as mouldy-acidic. In Chenin blanc, additions of TCA, in the concentration
range 1 to 17 ng/L, resulted in a marked increase in the mouldy aroma and was
accompanied by an immediate decrease in fruitiness. This change was already evident at
added TCA concentrations of 1 ng/L. Similar trends were observed in Pinotage, while the
addition of low levels of TCA to Shiraz (2 ng/L) resulted in a significant (P 0.05) decrease in
the herbaceous character of the wine. The aroma changes observed were prominent
enough to render the wine totally unacceptable in comparison to its original character.
Consumers’ degree of liking did not seem to be affected by very low concentration levels of
TCA in Chenin blanc, Pinotage or Shiraz, but rejection increased as the concentration
increased beyond detection threshold level. A slight gender effect was also noticed. Female
consumers appeared to be more sensitive to increasing levels of TCA, whereas male
consumers did not respond as negatively to higher concentration levels of TCA.
This study makes an important contribution towards understanding the sensory impact of
especially TCA contamination in wine, through the establishment of concentration ranges at
which these compounds exert a noticeable detrimental effect on the aroma profile of wine.
Additional insight into cork taint in wine is provided by the consumer preference studies,
where the effects of the taint on the product acceptance by consumers are demonstrated.
The development of a modus operandi to ensure that sensory panels provide reliable data,
can be regarded as an important contribution to wine-related research. This study is one of
the first where advanced sensometric techniques were applied in sensory studies on cork
tainted wines.
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Estudo sobre a razão de produção difrativa e total de B+→ Ј/Ψ K+ no CMS / Study of the diffractive production ratio of B+→ Ј/Ψ K+ at CMSDilson de Jesus Damião 25 May 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O presente trabalho refere-se ao estudo sobre a razão da produção difrativa e total de B+ decaindo em J=y +K+, no ambiente do experimento CMS do colisor de prótons LHC do
CERN, contribuindo assim com a compreensão geral do Modelo Padrão (SM) como a teoria das interações fundamentais entre as partículas elementares. Inicialmente, é apresentada uma
análise com o intuito de selecionar os eventos que possuem um méson B+, uma vez que o canal de decaimento mencionado: poderá ser a primeira medida da produção exclusiva do méson B à escala de energia do LHC; é um dos principais canais de fundo para outras análises; e possibilita
a utilização de um canal limpo para a calibração do CMS. Em seguida, é apresentada a forma de se identificar eventos difrativos no CMS, utilizando a baixa multiplicidade de torres ativas nos calorímetros CASTOR e HF. Esse estudo foi baseado em simulações computacionais, as quais reproduziram as condições físicas esperadas para o CMS/LHC, à energia de centro de massa de 10 TeV. Utilizou-se na geração de eventos o Monte Carlo POMWIG para as amostras difrativas e o PYTHIA para as demais. / This work concerns the study of the diffractive production ratio of the B+ meson decaying into J=y + K+, in the CMS/LHC environment, thus contributing to an general
understanding of the Standard Model (SM) as the theory of fundamental interactions between elementary particles. To begin with, an analysis is done in order to select the events that have B+, as the study of the mentioned channel could provide the first measurement of the exclusive production of B mesons at the energy scale of the LHC. Also, it is an important channel both for further analysis and to make CMS calibrations. Furthermore, we show how to identify diffractive
events in CMS, using low multiplicity of active cells in the forward calorimeters, HF and CASTOR. This study was based on computer simulations, which reproduce the Physics conditions expected for CMS at 10 TeV. The POMWIG generator was used to produce the diffractive samples and the others were done with PYTHIA.
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Produção e caracterização de cerveja artesanal adicionada de gengibre (Zingiber officinale) / Production and characterization of handmade ginger beer (Zingiber officinale)Tozetto, Luciano Moro 28 April 2017 (has links)
O mercado cervejeiro passa por uma revolução voltada à produção em escala artesanal ao invés de escala industrial, devido às expectativas dos consumidores em busca de alta qualidade e novo sabor do produto final. Visando produzir uma cerveja leve com relação ao teor de extrato e álcool, com sabor diferenciado, foram realizados vários ensaios de adição de gengibre no processo de produção. O mais viável resultado foi obtido com adição de 2g L-1 de lascas de gengibre in natura na maturação. A cerveja artesanal adicionada de gengibre foi produzida em escala laboratorial, para permitir sua análise físico-química e análise sensorial. Paralelamente, foram analisadas outras vinte e oito amostras de cerveja Pilsen para efeitos comparativos com relação aos aspectos físico-químicos. De acordo com o resultado do teste sensorial, o índice de aceitabilidade global foi de 92%, estando também acima de 70% o índice dos atributos individuais avaliados. A cerveja artesanal adicionada de gengibre apresentou características mais próximas às amostras de “Cerveja” ao invés das amostras “Puro Malte”, segundo classificação com relação ao teor de malte, por meio de análises quimiométricas (PCA e HCA). Essa discriminação entre os grupos foi devida aos teores de álcool, grau real de fermentação, grau aparente de fermentação, potássio, calorias e magnésio. O produto final apresentou como características principais um baixo teor alcoólico (3,40o GL), baixo valor energético (115,44 KJ 100 mL-1) e extrato reduzido (7,81º Plato). Apesar do amargor mais acentuado (21,55 B. U.), o índice de aceitabilidade para o amargor permaneceu acima de 70%, com flavor picante e aromático. / The brewing market undergoes a revolution directing to production on a homemade scale rather than an industrial scale, due to the expectations of consumers searching high quality and new flavor of the final product. In order to produce a light beer with respect to the extract and alcohol content and different flavor, several ginger addition tests were carried out in the production process. The most viable result was obtained with addition of 2 g L-1 of ginger flakes in natura at maturation. The artisanal brewed beer of ginger was produced in laboratory scale, to allow its physical-chemical analysis and sensorial analysis. In parallel, others twenty-eight samples of Pilsen beer were analyzed for comparative purposes in relation to physico-chemical aspects. According to the result of the sensorial test, the overall acceptability index was 92% as also as individual attributes evaluated were also above 70%. The artisanal beer added with ginger showed characteristics closer to the "Beer" samples than the "Pure malt" samples, according to classification in relation to the malt content, by means of chemometric analyzes (PCA and HCA). This discrimination between groups was due to alcohol, real degree of fermentation (RDF), apparent degree of fermentation (ADF), potassium, calories and magnesium. The final product had a low alcohol content (3.40 oGL), low energy (115.44 KJ 100 mL-1) and reduced extract (7.81 oPlato). Despite the more pronounced bitterness (21.55 B. U.), the acceptability index forbitterness remained above 70%, with spicy and aromatic flavor.
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