Grape pomace extract improves the in vitro and in vivo antioxidant properties of wines from sun light dried Pedro Ximénez grapes

Investigating Six Common Pesticides Residues and Dietary Risk Assessment of Romanian Wine Varieties

The food and environmental safety debate extends to the use of pesticides in agriculture including the wine sector, which is one of the most intensive pesticide users across the agricultural sector. Pesticide utilisation is a common agricultural practice to protect fruits and plants from pathogens and insects while maintaining high production levels. Grapevine is generally a crop that is subject to intensive phytosanitary treatments, and therefore, it can be assumed that pesticide residues will accumulate in the vine-shoots and, later on, end up in the grapes and wines. The aim of this study was to determine the pesticide content in red, rosé, and white wines after phytosanitary treatments applied in the vineyard and their impact on long-term dietary risks. The following six pesticides were analysed: oxathiapiprolin, myclobutanil, iprovalicarb, tebuconazole, chlorantraniliprole, and acetamiprid. Samples were extracted using the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method and analysed for the residues of pesticides by liquid chromatography-tandem mass spectrometry. Results indicated that the observed pesticides in the wine samples ranged between 0.05 and 0.75 ng/g. Dietary risks due to pesticide residues for women and men were evaluated using the estimated daily intake (EDI), hazard quotient (HQ), and hazard index (HI) of wines. The HQs and HIs did not surpass the 1 value (HQ, HI < 1) for both women and men, denoting that the concentrations of pesticide residues in these wine samples do not pose any immediate risk to consumers. Moreover, a pesticide residue intake model (PRIMo) model analysis was conducted, and the results suggest that European adult consumers have a low pesticide residue intake due to moderate wine consumption. However, pesticide residue intakes have been associated with several human health problems and high toxicity levels, therefore reliable analytical methods to monitor their presence in horticultural crops is crucial for clean and safe food products and healthy consumers.

Development and Functional Analysis of Lithocarpus polystachyus (wall.) Rehd Black Tea

This study examined the development conditions and functional properties of a novel compound tea Lithocarpus polystachyus (wall.) Rehd (L. polystachyus, LPR) black tea (LPRBT). The compound tea was developed by fermentation using fresh leaves (Camellia sinensis cv. Qianmei 601) as the main raw material with LPR powder as an additive. Based on the single factor and orthogonal tests with sensory scores as indicators, a withered leaves–LPR powder mass ratio of 9:1 with a 6 h fermentation time was determined to be the production condition of LPRBT with a sensory score of 89.09. In addition, phlorizin content, anti-oxidation function, hypoglycemic function, and tumor suppressor effect of LPRBT were measured. The results demonstrated that LPRBT phlorizin content was significantly higher than apple. It also showed that the equivalent 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical clearance rate with Vitamin C (Vc) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical clearance rate was 81% of Vc. Both hydroxyl and superoxide anion radical clearance increased with the increase in LPRBT amount. LPRBT also showed a good inhibitory effect on α-glucosidase and α-amylase, indicating certain hypoglycemic activity. Moreover, it inhibited the growth of HeLa and A549 cancer cells showing tumor suppressor activity. This study provides a reference for the development and application of LPR food products.

A Study of Overripe Seed Byproducts from Sun-Dried Grapes by Dispersive Raman Spectroscopy

Overripe seeds from sun-dried grapes submitted to postharvest dehydration constitute a scarcely investigated class of vinification byproduct with limited reports on their phenolic composition and industrial applications. In this study, Raman spectroscopy was applied to characterize a selection of overripe seed byproducts from different white grapes (cv. Moscatel, cv. Pedro Ximénez and cv. Zalema) submitted to postharvest sun drying. The Raman measurements were taken using a 1064 nm excitation laser in order to mitigate the fluorescent effect and the dispersive detection scheme allowed a compactness of the optical system. Spectroscopic data were processed by a principal component analysis to reduce the dimensionality and partner recognition. The evolution of the Raman spectrum during the overripening process was compared with the phenolic composition of grape seeds, which was determined by rapid resolution liquid chromatography/mass spectrometry (RRLC/MS). A multivariate processing of the spectroscopic data allowed the classification of overripe seeds according to the grape variety and the monitoring of stages of the postharvest sun drying process.

Evaluation of different methodologies for the determination of phenolic compounds in tropical fruits

Abstract Phenolic compounds are natural antioxidants and can be found with abundance in fruits and vegetables. One of the first methods created for analyzing phenolic compounds was the Folin-Denis method; and hereafter, the Folin Ciocalteu method was developed and recently, one of the most recent method is the Fast Blue. Due to the importance of these compounds in food, this work aimed to determine the total phenolic compounds in three fruits, such as: Passion Fruit, “Palmer” mango and “Pera” orange. In addition, these fruits were analyzed through three different determination methods. Furthermore, the content of vitamin C, soluble solids, titratable acidity and pH of these fruits were evaluated. Based on the results, it was verified that there was no difference among the values of vitamin C, soluble solids and TA in relation to those found in the literature. When comparing the three methods (Fast Blue BB, Folin-Ciocalteu Reagent and Folin-Denis Reagent), the results showed a difference in the phenolic compounds that may be related to the distinct reagents used in each method and its different action.

Natural extracts from grape seed and stem by-products in combination with colloidal silver as alternative preservatives to SO2 for white wines: Effects on chemical composition and sensorial properties

The search for alternative additives to sulfur dioxide, with antioxidant and antimicrobial activity, in the production of wines is one of the current objectives of the enological industry. In the present study, aqueous extracts obtained from winery byproducts (grape seeds and stems), alone or in combination with colloidal silver complex, have been used in white vinification. The antimicrobial effect of the extracts was similar to that of sulfur dioxide, being more effective on lactic and acetic bacteria in those wines to which colloidal silver was added. The effect on the color, the phenolic compounds and the volatile fraction of the wines was evaluated, as well as their sensory profile. The use of both extracts modified the color of the wines, increasing the chromatic parameters a* and b*, indicating a browning tendency, although no other signs of oxidation were found. Wines with seed extracts contained higher amounts of flavan-3-ols, and a significant increase in some volatile compounds such as fatty acid ethyl esters and benzene compounds, which were identified in the extracts. From a sensorial point of view, the wines with stem extracts were the most similar to those elaborated with SO₂, detecting a certain bitterness in wines with seed extracts.

Impact of a post-fermentative maceration with overripe seeds on the color stability of red wines

With the purpose of modulating the copigmentation equilibria of red wines, an environmentally sustainable process was performed based on post-fermentative addition of overripe seeds (OS). Simple (SW) and double (DW) addition were performed to produce different enrichment of phenolics from seeds, hence different copigmentation/polymerization ratios. The determination of the phenolic composition showed different global increases in OS-macerates wines (catechin, epicatechin, gallic acid and procyanidins B1 and B2). The double post-maceration (DW) was more effective than the simple post-maceration addition to improve the phenolic structure of wines. The application of Differential Tristimulus Colorimetry could assess the effects of this practice on the color characteristics and stability of wines. Results highlighted that both simple and double assays underwent colorimetric improvements against the control wines (CW, no seeds addition). DW led to the highest chromatic stability, showing lower lightness, higher chroma values and bluish hues than CW. This color difference was visually detectable.

Preparation and Antioxidant Activity of Ethyl-Linked Anthocyanin-Flavanol Pigments from Model Wine Solutions

Anthocyanin-flavanol pigments, formed during red wine fermentation and storage by condensation reactions between anthocyanins and flavanols (monomers, oligomers, and polymers), are one of the major groups of polyphenols in aged red wine. However, knowledge of their biological activities is lacking. This is probably due to the structural diversity and complexity of these molecules, which makes the large-scale separation and isolation of the individual compounds very difficult, thus restricting their further study. In this study, anthocyanins (i.e., malvidin-3-glucoside, cyanidin-3-glucoside, and peonidin-3-glucoside) and (–)-epicatechin were first isolated at a preparative scale by high-speed counter-current chromatography. The condensation reaction between each of the isolated anthocyanins and (–)-epicatechin, mediated by acetaldehyde, was conducted in model wine solutions to obtain ethyl-linked anthocyanin-flavanol pigments. The effects of pH, molar ratio, and temperature on the reaction rate were investigated, and the reaction conditions of pH 1.7, molar ratio 1:6:10 (anthocyanin/(–)-epicatechin/acetaldehyde), and reaction temperature of 35 °C were identified as optimal for conversion of anthocyanins to ethyl-linked anthocyanin-flavanol pigments. Six ethyl-linked anthocyanin-flavanol pigments were isolated in larger quantities and collected under optimal reaction conditions, and their chemical structures were identified by HPLC-QTOF-MS and ECD analyses. Furthermore, DPPH, ABTS, and FRAP assays indicate that ethyl-linked anthocyanin-flavanol pigments show stronger antioxidant activities than their precursor anthocyanins.

Correlações entre compostos fenólicos e atividade antioxidante em casca e polpa de variedades de uva de mesa

Resumo Uvas são consideradas excelentes fontes de compostos fenólicos, quando comparadas a outros vegetais; porém, a grande diversidade entre as cultivares resulta em frutos com diferentes características, tanto de sabor quanto de coloração, o que, certamente, está associado com o conteúdo e o perfil de compostos polifenólicos. Cascas e polpas de amostras de uva no ponto de consumo − tipos “Itália”, “Brasil”, “Rubi”, “Thompson” e “Niágara Rosada” − da região de Campinas e Jundiaí, Estado de São Paulo, foram estudadas com o objetivo de avaliar a atividade antioxidante, a atividade enzimática da peroxidase e da polifenoloxidase e os teores de compostos fenólicos e de ácido ascórbico. A fim de verificar as correlações entre as cascas e polpas das variedades e as características, utilizou-se a Correlação de Pearson, a distância generalizada de Mahalanobis (D2) e, por fim, o agrupamento das diferentes respostas através da análise multivariada. Verificou-se que as cascas das uvas analisadas apresentaram correlação positiva com o conteúdo de compostos fenólicos, a atividade da enzima polifenoloxidase e com o teor de ácido ascórbico, exceto a cultivar “Niágara Rosada”, a qual mostrou maiores valores para estas avaliações. Não houve correlação entre o índice de atividade antioxidante com as demais análises realizadas. As cascas se mostraram uma ótima fonte para estes compostos.

A Naturally Occurring Antioxidant Complex from Unripe Grapes: The Case of Sangiovese (v. Vitis vinifera)

The wine industry is well known for its production of a large amount of wastes and by-products. Among them, unripe grapes from thinning operations are an undervalued by-product. Grapes are an interesting source of natural antioxidants such as flavonoids, non-flavonoids and stilbenes. A potential strategy to exploit unripe grapes was investigated in this study. Juice from unripe grapes, v. Sangiovese, was obtained by an innovative technique of solid-liquid extraction without the use of solvents. The juice was dried by a spray-drying technique with the addition of arabic gum as support to obtain powder; juice and powder were characterized for antioxidant activity, phenolic concentration and profile. Phenolic acids, flavonols, flava-3-ols, procyanidins and resveratrol were detected in the juice and powder. The powder was used as anti-browning additive in white wine to test the potential re-use of the unripe grapes in the wine industry. The results indicated that the antioxidant complex from unripe grapes contributed to increasing the anti-browning capacity of white wine. Other applications, such as food and nutraceutical products development, can be considered for the antioxidant complex extracted from unripe grapes. In conclusion, the method proposed in this study may contribute to the exploitation of unripe grapes as a by-product of the winemaking process.

Phytochemicals, Monosaccharides and Elemental Composition of the Non-Pomace Constituent of Organic and Conventional Grape Juices (Vitis labrusca L.): Effect of Drying on the Bioactive Content

Grape and grape derivatives contain a variety of antioxidants that have gain increasing interest for functional foods applications. The chemical composition of grapes is mainly related to grape variety and cultivation factors, and each grape constituent exhib its unique characteristics regarding its bioactive properties. This study investigated the chemical composition and the effect of drying on the bioactive content of the non-pomace constituent obtained in the processing of organic and conventional grape juices from V. labrusca L. The non-pomace samples were analyzed for polyphenols, monosaccharides, antioxidant activity and elemental composition and the effect of drying on the bioactive composition was evaluated in samples subjected to lyophilization and drying with air circulation. The analyses revealed high concentrations of proanthocyanidins, flavanols and anthocyanins, and high antioxidant capacity of the organic and conventional samples. The drying processes reduced significantly (P < 0.05) the total phenolic content that ranged from 13.23 to 36.36 g/kg. Glucose, xylose, and mannose were the predominant monosaccharides, whereas K, Ca and Mg were the most abundant minerals. Variations in the chemical composition of organic and conventional samples were associated with cultivation factors. Nevertheless, this non-pomace constituent is a promising source of nutrients and polyphenols with bioactive potential.