首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 442 毫秒
1.
This study investigated lipid oxidation in spaghetti enriched in long chain n−3 polyunsaturated fatty acids (LC n−3 PUFA) by the addition to semolina of an integrator containing eicosapentaenoic acid and docosahexaenoic acid. Two oxidative parameters were evaluated: peroxide value (PV), to assess primary oxidation and oxidised fatty acids to quantify secondary oxidation products. Functional spaghetti had a shelf life comparable to control pasta. LC n−3 PUFA were not significantly implicated in the onset of oxidation in spaghetti stored under daylight and accelerated oxidation in a laboratory heater. Storage decidedly affected shelf life: PV in functional spaghetti increased from 7.1 to 43.4 meq O2/kg of fat under light exposure over 12 months, and from 7.1 to 16.2 meq O2/kg under accelerated ageing at 55 °C for 27 days, reproducing about 18 months at room temperature. Oxidised fatty acids increased in fortified spaghetti from 4.8 to 13.8 g/100 g of fat under light exposure over 12 months and from 4.8 to 7.8 g/100 g of fat at 55 °C in 27 days. The high sensitivity of spectrophotometric and chromatographic analytical methods permitted the evaluation of primary and secondary oxidative derivatives in small amounts of fat.  相似文献   

2.
The objective of this study was to measure the oxidation of linoleic acid of nixtamalised corn masa (NCM) during an accelerated shelf life study at high temperature (45–85 °C), and 0.45 aw for 180 days. Linoleic acid (LA) was present at 55.1%, followed by oleic acid (26.9%), as measured by gas chromatography. The propagation of lipid oxidation, measured by anisidine value, reached its peak 2–5 days after the peroxide value had passed over its maximum value. At this time, flour showed at least a 10% reduction of LA; but, at the end of storage only 10% of LA remained. The autocatalytic oxidation of linoleic acid in NCM was temperature-dependent, with Q10 = 1.4. The index of quality loss for corn flour stored at 55 °C was 0.48% per day; under these conditions 50% of its quality decreased in only 104 days. Mathematical modelling estimates a shelf life of 84 days for corn masa (<6 meq/kg peroxide) stored at 25 °C.  相似文献   

3.
Sparkling wine produced by the traditional méthode champenoise requires a second in-bottle alcoholic fermentation of a base wine, leading to the sparkling wine. This second fermentation is followed by prolonged ageing in contact with yeast cells (lees). The autolysis of yeast occurs during the ageing of sparkling wines. During this process, the yeast releases different compounds that modify the organoleptic properties of the wine. The ageing period is required to give these wines their roundness and characteristic aroma and flavour. Autolysis products also influence the foaming properties of sparkling wine. Yeast autolysis is characterised by the hydrolysis of intracellular biopolymers by yeast enzymes activated after cell death. This results in the release of low molecular weight products. This article reviews the recent advances in understanding the yeast autolysis mechanism, the factors affecting autolysis, the nature of the released compounds and their effects on sparkling wine quality.  相似文献   

4.
The Brachetto variety is the most important aromatic red grape used for the production of sweet sparkling wines in Italy. The phenolic composition and chromatic characteristics were studied in base and red sweet sparkling wines made from this variety. The present work represents the first study on sparkling wines manufactured with Brachetto grapes. The amount of pigments extracted in the base wine was low as a consequence of the necessity for short maceration time (48 h) and low alcohol content (< 3.5% v/v). The second fermentation (prise de mousse) caused a pigment content decrease, accompanied by both a color intensity decrease and a tonality increase. In terms of phenolic compounds and chromatic characteristics, lightly sparkling wines (final bottle pressure < 1.7 bar) agreed with fully sparkling wines (final bottle pressure > 3.0 bar) at the end of the second fermentation and, therefore, the chromatic quality was independent on the winemaking methodology used, excepting for lightness and color intensity.Response surface methodology was applied to predict the effect of two independent variables, namely time and temperature of storing, on the phenolic composition and chromatic properties in both lightly and fully sparkling wines. So, it is possible to evaluate the development of two types of sweet sparkling wines during their ageing in bottle and their commercial shelf-life. A central composite design (CCD) and response surface methodology (RSM) were used for this purpose. Quantitative changes were observed in the color parameters. Although the time variable strongly influenced them, the two sparkling wines were stable enough only at low temperatures after 12 months of ageing. During the wine ageing in bottle, an increase in the formation of polymeric red pigments can be suggested taking into account the losses observed in monomeric anthocyanins. The results obtained showed that the color of fully sparkling wines was more stable than that of lightly ones and, therefore, the shelf-life of the former ones could be longer.  相似文献   

5.
The aim of this study was to elucidate the structure of a potential ageing marker for Cava sparkling wine. In order to clarify the structure of this compound, NMR spectroscopy and hyphenated UHPLC-DAD-MS/MS techniques were used. We identified the hitherto unknown compound as 5-hydroxymethyl-2-furfuraldehyde (5-HMF). This is the first time that this compound has been reported in sparkling wines. A survey, based on the analysis of 80 commercial sparkling wines, showed that 5-HMF is present between 0.25 and 12.81 mg/L, and is compared with those reported for other types of wine. Hypothetical origin of 5-HMF in Cava sparkling wine is discussed.  相似文献   

6.
The objective of this study was to evaluate the shelf life of powdered guavira pulp obtained by a foam mat drying process. The dehydrated guavira pulp was packed into low density polyethylene (LDPE) bags and stored under two controlled conditions: environmental (25 °C, RH 75%) and accelerated (35 °C, RH 90%) for 90 days. The shelf life was accompanied by carrying out the following analyses every 10 days: moisture content, water activity, vitamin C content, pH and titratable acidity. Vitamin C was the quality attribute used to determine the shelf life of the product, by determining its degradation kinetics as a function of storage time. The linear regression data showed that the vitamin C degradation reaction fitted the zero and first order kinetic models. The shelf life of the powdered guavira pulp under environmental conditions was approximately 49 days, and under accelerated conditions (35 °C) 45 days. The Q10 was equal to 1.09, predicting a shelf life similar to that found under environmental conditions. The moisture content for these conditions was 10.0% e 5.4% for 35 °C and 25 °C, respectively. The above demonstrate the efficiency of the accelerated test in predicting the shelf life of the product.  相似文献   

7.
The influence of the second fermentation step on sparkling wine aroma was investigated with respect to the content of 2-aminoacetophenone (AAP) as an indicator substance for the atypical ageing off-flavour (ATA). AAP contents of aged sparkling wines and their corresponding base wines (Riesling and Chardonnay variety) were determined by means of multidimensional gas chromatography using a stable isotope dilution assay. The majority of sparkling wines were lower in AAP in comparison with their corresponding base wines. Explorative and predictive statistical analyses of the resulting AAP content in sparkling wines were performed concerning the influence of the parameters lees contact time, yeast strain, base wine AAP concentration and total phenolic contents. Both statistical approaches yielded good fits with AAP concentration of the base wine being the predominant factor. Although it was possible to explain the changes in AAP concentrations on the basis of how total phenolics changed during second fermentation, predicted AAP trends did not hinge upon the amount of total phenolics present in a base wine. Unpressurised model fermentations were a promising technological alternative to study the development of AAP in sparkling wines. Altogether, this study presents a multidisciplinary approach to master the challenging task of ATA risk assessment in base wines, which at present rather accesses the sparkling wine producer’s individual experience.  相似文献   

8.
《Food chemistry》1998,63(4):465-471
Soluble proteins from sparkling wines (var. Chardonnay) manufactured industrially following the Champenoise method were analysed by analytical anion-exchange FPLC (fast protein liquid chromatography). Samples of the must, the unfined wine, the fined wine and the sparkling wines after 3, 6, 9, 12, 15 and 18 months of ageing with yeast lees were taken. Eight main must protein fractions were collected and characterized by isoelectric focusing and capillary electrophoresis. Six fractions consisted of proteins with isoelectric points (pIs) from 4.27 to 3.04. Two fractions, according to their UV spectra, seemed to contain phenolic compounds. A comparison of FPLC profiles of the must, the unfined wine and the fined wine indicated that both fermentation and stabilization processes decrease the concentration of those proteins with less affinity for the anion-exchange column and with a higher pI. No changes in the protein profiles of sparkling wines were observed during the first 18 months of ageing with yeast..  相似文献   

9.
Nerea Jiménez Moreno 《LWT》2007,40(4):619-624
The retention of wine volatile compounds by wine lees could have an influence on the quality of the product. The aim of this work was to study the binding of wine volatile compounds from oak wood by the wine lees during simulation of wine ageing. The compounds with the most affinity for the lees were eugenol, 4-propylguaiacol, 4-methylguaiacol, furfural and 5-methylfurfural. Lees also bound other compounds important for aroma in aged wine such as oak lactones, although to a lesser degree. Guaiacol and γ-nonalactone were the only compounds studied that were not bound by the lees. Because the lees bind important compounds to wine aroma, ageing red wine in oak barrel in presence of lees could diminish the impact of the aromatic compounds from oak wood on wine aroma.  相似文献   

10.
Most research on extraction of phenol compounds from wine by-products and commercial exploitation of extracts use grape seeds and/or skins as raw materials. Looking for alternative antioxidants sources, obtaining antioxidant extracts from wine lees (also known as dregs), a sub-exploited by-product of winemaking process, is here presented. Microwave-assisted extraction (MAE) of phenolic compounds from wine lees has been optimized using the total phenols index, the ORAC values and yield of the extraction as response variables. Under the optimal working conditions, the proposed MAE method provides better extraction efficiency in a much shorter time (17 min) than the conventional extraction method for phenolic compounds (24 h). The liquid extract obtained by MAE was spray-dried. The type and amount of excipients used, as well as the spray-drying temperature, were optimized in order to minimize the oxidation of phenolic compounds and maximize the yield of the spray-drying process. The total phenols index in the dried extract thus obtained was 36.8% (expressed as gallic acid), showing an ORAC value of 3930 μmol TE/g. Additionally, Mv3G, Cm-Mv3G, myricetin, quercetin, quercetin-3-β-glucoside, caffeic acid and p-coumaric acid were quantified in the dry extract by HPLC–DAD. The results indicate that wine lees antioxidant extracts can be a suitable and cheap alternative to those obtained from grape seeds or skins.  相似文献   

11.
The peptide fraction of an industrially manufactured red wine has been studied during malolactic fermentation, carried out in stainless-steel tanks or in the barrel and ageing in the barrel, with or without lees, for 12 months. Peptides were fractionated using Sephadex LH-20 and Cosmosil 140 C18-OPN columns, giving two fractions in relation to peptide polarity. The most important changes were detected during malolactic fermentation and during the ageing in barrel with lees. The peptides present in the wine could be glycopeptides from grape or yeast. Most amino acids in the most polar peptides were aspartic acid and/or asparagine, glutamic acid and/or glutamine, serine, glycine, α-alanine and tyrosine and, in the less polar fraction, were glycine, α-alanine and leucine. The amino acid distribution is most different in the most polar fraction, among the studied wines, owing to autolysis and hydrolysis of the polypeptides and proteins.  相似文献   

12.
Light lees that spent more than one year in barrels were used for ultrasound-assisted yeast lysis (22 W/L, 18 °C) in a model wine. For comparison, a classical yeast autolysis at mild temperature (25 °C) was performed. The effect of ultrasound on lees was evaluated by analysing the release of proteins and polysaccharides to the model wine, and the viability of the yeasts contained in the lees. Under conditions tested, ultrasound-assisted yeast lysis increased the concentrations of proteins and polysaccharides in the model wine due to the release of these compounds from yeasts. Unlike the classical autolysis, ultrasound led to a high cell disruption, and after 20 h of ultrasonic treatment, viable cells were hardly found. Furthermore, the final cell concentration for the ultrasound-assisted yeast lysis was much lower than that for the classical autolysis. The inactivation rate constant of ultrasound-assisted yeast lysis was 2.54 × 10−5 s−1. Finally, the morphological changes in cells were examined by scanning electron microscopy to verify the effect of ultrasound on yeast cells.  相似文献   

13.
Sparkling wines are produced by a secondary fermentation of a base wine followed by a prolonged ageing in contact with lees. In the traditional method, the refermentation takes place in the same bottle used for market distribution. The autolysis of yeasts occurs during the ageing of sparkling wines, thus causing the release of many parietal and cytoplasmic compounds which have a great influence on sparkling wine’s quality. The modern technologies for the production of sparkling wine are very different from the one developed by Abbot Dom Pierre Pérignon in the 17th century. Over the years, many advances have been made, this paper aims at reviewing the recent knowledge in the application of biotechnologies for the improvement of sparkling wine’s quality, in particular the factors affecting foaming properties and sensory qualities. Future perspectives and trends are also considered.  相似文献   

14.
The effects of finishing time, (T0 = 0, T1 = 30 and T2 = 60 days), on Holstein–Friesian cull cows (n = 18) and post-mortem ageing, (1, 7, 14, 21, 35 and 42 days), under vacuum conditions of Longissimus thoracis (LT) muscles were investigated. The objective of this research was to study how finishing feeding (based on a commercial concentrate and corn silage), following a pasture period of 90 days, affected carcass and meat quality. Ageing time effect was also evaluated on the main quality attribute of added value pieces, such as “striploin of ox” from cull cows. Finishing treatment affected intramuscular fat content (IMF), moisture percentage, water-holding capacity (WHC), colour parameters and shear force of meat at 24 h post-mortem, whereas ageing time enhanced meat tenderness, when this was measured by two textural tests, Warner–Braztler (WB) and textural profile analysis (TPA). A minimum shear force was achieved at 7 and 14 days of ageing for T1 and T2, respectively. No differences (P > 0.05) could be found in colour parameters from 7 to 42 days. The results show that a finishing time of two months is very beneficial, due to the increase in meat fatness, improved overall carcass quality and luminosity (L*). Furthermore, 14 ageing days were sufficient to improved tenderness. Ageing time did not have an effect on lipid oxidation (P > 0.05) and this leads us to conclude that meat shelf life exceeded 42 days under vacuum conditions’.  相似文献   

15.
The influence of different over-lees ageing conditions on the soluble polysaccharides?? glycosyl residue and volatile composition of Cabernet wine was addressed in this work. Specific operating conditions have been considered: wine ageing on fine white lees, wine ageing on fine red lees, wine ageing on fine second-passage white lees and short ageing on rough red lees, which were compared with ageing without lees. The ageing on lees led to an increase in all wine polysaccharide glycosyl residues, with the exception of glucose, xylose and myo-inositol, and to volatile profile modifications. Different behaviours could be observed between the four types of lees, giving important hints for a rational use of them in winemaking. In particular, the use of red grape-derived lees caused the major release of polysaccharides; on the other hand, white grape-derived lees were more effective in enhancing ester content. Second-passage lees did not lead to any increase in wine polysaccharides, whereas they allowed aroma changes, and short ageing on rough red lees caused the greatest adsorption of several volatiles.  相似文献   

16.
Broccoli (Brassica oleracea var. italica) is a vegetable that requires the application of postharvest techniques to extend its marketability. Controlled atmosphere and 1-MCP treatments are most used to extend the shelf life of broccoli and reduce post-harvest deterioration. The aim of this study was to evaluate the visual, physicochemical and functional changes of broccoli head samples stored at 1–2 °C and 85–90% relative humidity (RH) in air (Control samples), under controlled atmospheres (10% O2 and 5% CO2) (CA samples) and treated with 1-MCP (0.6 μL/L). After storage all samples were maintained at 20 °C for 2 and 4 days, in order to assess their shelf life. The most suitable postharvest treatment to extend broccoli quality during storage and shelf life, in terms of maintaining the visual quality and reducing loss of health-promoting compounds, was achieved by storage under controlled atmosphere conditions. The use of 1-MCP reduced the loss of green colour and chlorophyll pigments, but only during cold storage not during shelf life at 20 °C.  相似文献   

17.
This paper reports the influence of yeast strain and aging time on the volatile composition of sparkling cider made according to the traditional method. Two sparkling ciders were obtained from the same base cider using a selected cider yeast strain (Saccharomyces bayanus) and a commercial wine yeast strain (Saccharomyces cerevisiae). Analysis of volatile compounds (alcohols, esters and carbonylic compounds) were performed every 3 months, from 3 to 15 months. The analysis of variance revealed that the majority of differences between sparkling ciders are due to the aging time. Acetaldehyde and acetoin decrease with time, while higher alcohols, ethyl acetate, ethyl lactate and ethyl octanoate significantly increase during aging in contact with lees. The concentrations of methanol, 2-phenyletanhol, ethyl lactate and ethyl octanoate were higher in the cider made with the selected yeast strain (S. bayanus).  相似文献   

18.
19.
The objective of this study was to determine the influence of carbonation level on the sensory and chemical properties of traditional sparkling wine and identify the level of carbonation that could be perceived by consumers. Sparkling wine treatments (n?=?11) were produced through the addition of different concentrations of dextrose at bottling to create sparkling wines varying in carbonation (CO2) level. Final wines ranged in CO2 concentration from 0 to 7.5?g?CO2/L (p?≤?.05). A consumer sensory evaluation panel (n?=?48) evaluated the wines using a paired comparison test in which a sparkling wine at CO2 concentrations of 1.2, 2.0, 4.0, 5.8, or 7.5?g CO2/L was compared to the control sparkling wine (0?g CO2/L) for mouthfeel attributes (carbonation and bite) and sour taste. Results showed significant differences (p?≤?.001) between the control and sparkling wines containing 2.0, 4.0, 5.8, and 7.5?CO2/L for the mouthfeel attributes of carbonation and bite, suggesting that a minimum CO2 concentration of >1.2?g?CO2/L was required for consumers to detect mouthfeel differences compared to the control. The results of this study provide sparkling winemakers and manufacturers of other carbonated products with information regarding the level of CO2 perceived by consumers of sparkling wines.  相似文献   

20.
Hen’s egg lysozyme (LYZ) is added to red wine for preventing malolactic activity. Sulphur dioxide and polyphenolic compounds can depress LYZ solubility and effectiveness, likely by sulphonation of enzyme disulphide bonds or protein binding, respectively. These phenomena were evaluated in either young red wine or model wine systems. A reliable and validated HPLC method was first developed in order to quantify soluble LYZ in wine (r95% = 10.7 mg l−1). The amount of insolubilized LYZ in red wine was related to the content of non-anthocyan flavonoids of low molecular weight and enzyme precipitation occurred in few minutes when flavonoid concentration exceeded 50 mg l−1. Interaction between sulphur dioxide and LYZ occurred in polyphenol-free model wine systems and for the first time the formation of mono-thiosulphonated LYZ was demonstrated. This reaction was favoured by increasing pH value and sulphur dioxide concentration. Nevertheless, sulphonation alone did not fully explain LYZ instability in model wine systems.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号