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1.
Food Chem ; 305: 125484, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514048

RESUMO

Grape pathogenesis-related proteins can cause haze in wine that is undesirable for consumers. Bentonite is used to remove these proteins but is a non-renewable natural material and reduces wine volume due to poor settling. As a potential bentonite alternative, grape seeds powder (GSP) was added to four wines and two grape juice varieties. Addition to wine required high doses (25-32 g/L) for protein removal and haze prevention and this induced changes to wine composition. By contrast, addition to grape juice prior to fermentation required substantially lower doses of GSP (5 g/L) to prevent haze formation. Further 20 g/L of GSP added to the must induced less changes to wine composition than direct addition of GSP to the wine. No changes were recorded in the efficacy of protein removal by changing the GSP source (red or white grape marc), or by using grape seed roasting. Despite the need for additional trials, these preliminary results suggest that GSP may be considered as a viable alternative to bentonite especially when added to juice prior to fermentation.

2.
Nutrients ; 11(11)2019 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-31717543

RESUMO

BACKGROUND: While there has been an increasing interest in the health properties of chocolate, limited research has looked into the changes of antioxidants occurring in the time span from production to the best before date, which was a period of 18 months in this study. METHODS: Humidity, ash, pH, acidity, fiber, carotenoids, retinols, tocopherols, sugars, proteins, theobromine, caffeine, polyphenols, fats, the peroxide value, organic acids, and volatile compounds, along with the sensory profile, were monitored at 18-week intervals for 18 months under conditions simulating a factory warehouse or a point of sale. RESULTS: At the end of the storage period, more polyphenols were lost (64% and 87%) than vitamin E (5% and 14%) in cocoa mass and cocoa powder, respectively. Conversely, a greater loss in vitamin E (34% and 86%) than in polyphenols (19% and 47%) was shown in the hazelnut paste and gianduja chocolate, respectively. The sensory profiling of cocoa mass, cocoa powder, and hazelnut paste revealed increases in grittiness and astringency, as well as decreases in melting, bitterness, and toasted aroma. Moreover, in the hazelnut paste and gianduja chocolate, oiliness increased with a toasted and caramel aroma. Furthermore, dark chocolate was more gritty, acidic, and bitter. Milk chocolate lost its nutty aroma but maintained its sweetness and creaminess. CONCLUSIONS: These results should contribute an important reference for companies and consumers, in order to preserve the antioxidants and understand how antioxidants and sensory properties change from the date of production until the best before date.

3.
Food Chem ; 288: 78-85, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30902317

RESUMO

Oxidative spoilage is a phenomenon that can occur both in winemaking and during bottle storage. The complexity of oxidative spoilage makes it difficult to identify all the products from oxidation processes, especially in bottled wines with varying degrees of oxidative spoilage, i.e., "random oxidation". To this end, this study sought to obtain a deeper insight into the chemistry of white wine samples to identify compounds able to discriminate the different oxidative statuses. The results of metabolomics and VIP analysis outlined molecules such as 3-methylcatechol, cyanidin 3-O-6″-p-coumaroyl-glucoside, delphinidin 3-O-glucoside, quercetin 3-O-glucosyl-xyloside, dihydroquercetin, and quercetin 3-O-glucuronide to be discriminant in the detection of the oxidative status of the white wines under study, which were preliminarily classified in low and high oxidation classes by means of sensory analysis. Parameters such as total and free sulfur dioxide content and browning and pinking measurements were confirmed to remain significantly correlated with oxidation-related issues.


Assuntos
Metabolômica , Fenóis/análise , Vinho/análise , Antocianinas/análise , Cromatografia Líquida de Alta Pressão , Análise Discriminante , Glucosídeos/análise , Análise dos Mínimos Quadrados , Oxirredução , Fenóis/química , Espectrometria de Massas por Ionização por Electrospray , Dióxido de Enxofre/análise
4.
Food Chem ; 264: 301-309, 2018 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-29853380

RESUMO

This investigation focuses on the use of chitosan treatment simulating a bentonite fining in order to detect any modification of the wine haze potential by simultaneously evaluating the secondary effects on untargeted fixed and volatile compounds. A significant removal of chitinases was observed after fining an aromatic white wine with 1 g/L of a fungoid chitosan. Even if the more stable thaumatin like protein fractions were not significantly affected, the heat stability of the fined chitosan wine samples were highly improved in the 55-62 °C range. Among the secondary effects of a fining treatment, a reduction of tartaric acid, malic acid, potassium and iron was showed. All the free terpenols with the exception of α-terpineol were reduced in significant amounts, whilst the glycosylated forms and the fermentative aroma compounds were not affected by a 1 g/L chitosan addition.

5.
Food Microbiol ; 69: 179-188, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28941899

RESUMO

Starmerella bacillaris (synonym Candida zemplinina) is a non-Saccharomyces yeast that has been proposed as a co-inoculant of selected Saccharomyces cerevisiae strains in mixed culture fermentations to enhance the analytical composition of the wines. In order to acquire further knowledge on the metabolic interactions between these two species, in this study we investigated the impact of oxygen addition and combination of Starm. bacillaris with S. cerevisiae strains on the microbial growth and metabolite production. Fermentations were carried out under two different conditions of oxygen availability. Oxygen availability and strain combination clearly influenced the population dynamics throughout the fermentation. Oxygen concentration increased the survival time of Starm. bacillaris and decreased the growth rate of S. cerevisiae strains in mixed culture fermentations, whereas it did not affect the growth of the latter in pure culture fermentations. This study reveals new knowledge about the influence of oxygen availability on the successional evolution of yeast species during wine fermentation.


Assuntos
Ascomicetos/metabolismo , Oxigênio/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Vitis/microbiologia , Vinho/análise , Ascomicetos/crescimento & desenvolvimento , Etanol/análise , Etanol/metabolismo , Fermentação , Aromatizantes/análise , Aromatizantes/metabolismo , Saccharomyces cerevisiae/metabolismo , Vitis/metabolismo
6.
Food Chem ; 229: 734-742, 2017 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-28372238

RESUMO

Vinegar is an inexpensive commodity, and economic considerations require that a relatively low-cost raw material be used for its production. An investigation into the use of a new, alternative substrate - pineapple waste - is described. This approach enables the utilization of the pineapple's (Ananas comosus) peels and core, which are usually discarded during the processing or consumption of the fruit. Using physical and enzymatic treatments, the waste was saccharified, and the resulting substrate was fermented with Saccharomyces cerevisiae for 7-10days under aerobic conditions at 25°C. This resulted in an alcohol yield of approximately 7%. The alcoholic medium was then used as a seed broth for acetic fermentation using Acetobacter aceti as the inoculum for approximately 30days at 32°C to obtain 5% acetic acid. Samples were analyzed at the beginning and end of the acetification cycle to assess the volatile and fixed compounds by GC-MS and UHPLC-QTOF-MS. The metabolomic analysis indicated that l-lysine, mellein, and gallic acid were significantly more concentrated in the pineapple vinegar than in the original wine. Higher alcohols, aldehydes, and ketones characterized the aroma of the final pineapple vinegar, whilst off-flavors were significantly reduced relative to the initial wine. This study is the first to highlight the metabolite profile of fruit vinegar with a slight floral aroma profile derived from pineapple waste. The potential to efficiently reduce the post-harvest losses of pineapple fruits by re-using them for products with added food values is also demonstrated.


Assuntos
Ácido Acético/análise , Ácido Acético/metabolismo , Ananas/metabolismo , Metaboloma , Vinho/análise , Acetobacter/metabolismo , Ananas/química , Cromatografia Líquida de Alta Pressão/métodos , Fermentação , Aromatizantes/análise , Aromatizantes/metabolismo , Frutas/química , Frutas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas/métodos , Saccharomyces cerevisiae/metabolismo
7.
Food Chem ; 194: 247-56, 2016 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-26471551

RESUMO

The impact of postharvest withering rates on the phenolic composition of 'reinforced' wines produced with partially dehydrated grapes was evaluated. The study was performed on winegrape varieties with anthocyanin profiles differently constituted of di- and tri-substituted forms. Dehydration induced limited changes in the anthocyanin profile of berry skins. Nevertheless, the greatest abundance of total anthocyanins and their more stable forms (malvidin-3-glucoside and acylated glucosides) corresponded to the wines made from slow withered Chatus grapes, which were in turn the darkest. In contrast, the wines made from withered Avanà grapes did not meet good chromatic characteristics due to low contents of total anthocyanins and high ratios between di- and tri-substituted forms. Nebbiolo wines showed intermediate values of this ratio, and therefore of clarity and color intensity. The fast process is recommended because higher percentages of galloylated flavanols in the seeds of slow withered Nebbiolo grapes may have a negative influence on wine astringency.


Assuntos
Antocianinas/análise , Frutas/química , Glucosídeos/análise , Fenóis/análise , Vitis/química , Vinho/análise , Cor , Frutas/crescimento & desenvolvimento , Frutas/metabolismo , Itália , Vitis/crescimento & desenvolvimento , Vitis/metabolismo , Vinho/normas
8.
J Agric Food Chem ; 62(33): 8437-51, 2014 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-25111462

RESUMO

This study was performed to evaluate and compare the effects of different pre-treatments of whole grape berries (freezing with dry ice or in a cold room, steam blanching with different exposure times, and microwave heating with different exposure times and microwave power density) on total content of some phenolic compounds and the composition of individual anthocyanins released into the pulp during the treatment and those extracted during the maceration step. Two red winegrape varieties with different proportions of di- and trisubstituted anthocyanins were used (Nebbiolo and Barbera, respectively). Pulp-extracted anthocyanins were more significantly influenced by the pre-treatment. The results highlighted that freezing with dry ice, followed by freezing in a cold room and steam blanching for 5 min, have a great potential from an industrial point of view. They facilitated the extraction of anthocyanins in the must prior to maceration, when compared with the control samples, increasing their total content (+37.8-83.6%), and modifying the anthocyanin profile through the enrichment in the most stable compounds (+2.8-6.6% malvidin derivatives) to the detriment of others more prone to oxidation (-0.8-11.0% cyanidin derivatives). In Nebbiolo winegrapes, an improved extraction of low- and high-molecular weight flavanols into the pulp was also observed (+60.4-73.4%). Significant relationships between the phenolic composition of treated berries and the corresponding skin mechanical properties were also studied, but they were variety dependent. Discriminant analysis permitted a correct classification of the samples according to the variety and pre-treatment.


Assuntos
Antocianinas/isolamento & purificação , Manipulação de Alimentos/métodos , Frutas/química , Fenóis/isolamento & purificação , Vitis/química , Antocianinas/química , Fenômenos Biomecânicos , Fenóis/química
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