RESUMO
Climate changes are inducing increased sugar levels of must, which produces negative effects on wine quality, as unbalanced wines with high degrees of alcohol. So, effective strategies to control the increase of sugar levels in must have been studied. One of them is the use of a membrane process, and this is applied in this work. The sugar level of white must from Verdejo (Vitis vinifera variety) was reduced using diverse membrane processes, and the effect of this fact on the volatile composition of the corresponding wines is studied. The study was carried out during three consecutive vintages. An important impact of the reduction of sugar levels of must on the volatile composition of the obtained wines was detected, which was due to some retention phenomena of aromatic and precursor compounds. To minimize the volatile composition modifications, an appropriate selection of the nanofiltration membrane must be done.
Assuntos
Carboidratos/análise , Compostos Orgânicos Voláteis/análise , Vinho/análise , Aminoácidos/análise , Filtração/métodos , Manipulação de Alimentos/métodos , Frutas/química , VitisRESUMO
Spanish muffins are bakery products widely consumed in Spain. During their elaboration process MRPs are formed, being partially responsible for muffin characteristics including their antioxidant capacity. The main aim of the study was evaluating the amount, colour and antioxidant capacity of different fractions of MRPs (low and high molecular weight) isolated from commercial muffins. The fraction of high molecular weight (melanoidins) showed to have a higher antioxidant capacity, measured by ABTS and FRAP, than LMW ones. Significant and relatively close correlations between colour parameters and antioxidant capacity were observed for global MRPs, but only occasionally when isolated fractions of melanoidins and LMW were studied. As summary, it can be said that global MRPs present in muffins, apart from contributing to colour and flavour, can also contribute significantly to muffin conservation, due to their appreciable antioxidant capacity, which seems to be directly correlated with of their colour, although this fact is not extrapolated to isolated fractions of melanoidins and LMW MRPs.
Assuntos
Pão/análise , Reação de Maillard , Antioxidantes/química , Cor , Polímeros/química , EspanhaRESUMO
The wine is a beverage with an important antioxidant efficiency which is attributed to their bioactives compounds, especially polyphenols. The anthocyanins are the main phenolic compounds of red wine and its consumption has been partially related with the "French Paradox". The aim of the present work was to evaluate the contribution of the anthocyanins to the antioxidant properties of red wines. So, total antioxidant capacity (TAC), hydroxyl and superoxide scavenger activity and lipid peroxidation of 80 Spanish red wines and their anthocyanins fractions have been assessed for ABTS, DPPH, DMPD, and FRAP methods, hydroxyl radical (HRSA), superoxide radical scavenger activity (SRSA) and ABAP-lipid peroxidation (ABAP-LP). The results showed that free anthocyanins fraction are main responsible of the total antioxidant capacity of red wines correlated with electron transference processes. In similar way, free anthocyanins are the maximum responsible of HRSA scavenger activity of red wines, contributing less extensively to their SRSA capacity or to their protective action on lipid peroxidation. Furthermore, simple anthocyanins exert a low action in TAC process involved with proton transference. Glycosilated and methoxylic anthocyanins as malvidin-3-glucoside, seem to be the type of anthocyanins with higher participation on the antioxidant effect of red wine.
Assuntos
Antocianinas/química , Antocianinas/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Vinho/análise , Animais , Benzotiazóis/química , Compostos de Bifenilo , Compostos Férricos/química , Flavonoides/análise , Sequestradores de Radicais Livres/química , Radical Hidroxila/química , Masculino , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/enzimologia , Microssomos Hepáticos/metabolismo , Oxidantes/química , Estresse Oxidativo/efeitos dos fármacos , Fenóis/análise , Picratos/química , Piperidonas/química , Polifenóis , Ratos , Ratos Wistar , Substâncias Redutoras/química , Ácidos Sulfônicos/química , Superóxidos/químicaRESUMO
Different options of liquid chromatography-mass spectrometry were used to establish the most suitable ion source and conditions to analyse or detect some low-molecular mass phenols, flavan-3-ols, and apply such conditions to a complex sample (wine). Data presented in this work confirm the great utility of atmospheric pressure-ionisation electrospray mass spectrometry coupled to HPLC for analysis of phenolic compounds, under negative mode in the case of low-molecular mass phenols, and under both positive and negative modes in flavan-3-ol compounds. A fragmentor voltage of 60 V could be the most suitable for analysing the compounds under study.
