Chemometric analysis for authentication of 'Syrah' and 'Tempranillo' red wines of San Francisco Valley-Brazil compared to wines from other world regions by the molecular profile in HPLC.

The aim of this study was to evaluate the phenolic composition, sugars, and organic acids by HPLC-DAD/RID, and the antioxidant capacity of 100% commercial 'Syrah' and 'Tempranillo' red wines from the San Francisco Valley-SFV wineries, and to compare them with commercial monovarietal wines of the same cultivars from countries such as South Africa, Spain, Chile, and Australia. In total, 25 phenolic compounds were quantified and classified into chemical groups in all wines (phenolics acids, flavanones, flavan-3-ols, flavonols, anthocyanins, and stilbenes). Among these, catechin, procyanidins B1 and B2, lactic acid, and antioxidant capacity were highlighted as the markers responsible for the typification of SFV wines when compared to wines from temperate regions. The data reported here contribute to the knowledge of the potential for producing quality wines in tropical climate regions. The wines of cultivars 'Syrah' and 'Tempranillo' are consolidated among the wineries in the SFV region, Brazil, due to their excellent adaptation to the semi-arid tropical climate. The SFV recently applied for a wine geographical indication as its wines are young with tropical climate typicity. This study shows that it is possible to differentiate SFV Syrah and Tempranillo wines from other world regions by HPLC molecular profile using chemometric techniques. Supplementary Information: The online version contains supplementary material available at 10.1007/s13197-023-05739-7.

Phytochemical profile of Brazilian grapes (Vitis labrusca and hybrids) grown on different rootstocks.

Important factors may influence the bioactive compounds in grapes, including scion-rootstock interaction. Therefore, the bioactive compounds and antioxidant activity in grape skin and pulp fractions of 'Isabel Precoce', 'BRS Carmem', 'BRS Cora', 'BRS Violeta' and 'IAC 138-22 Máximo' were assessed. These cultivars, from genetic improvement programs in Brazil, have good adaptation to subtropical and tropical climate conditions, and can be widely used by winegrowers aiming at adding value to the grape. All grapevines were grafted onto 'IAC 766' and 'IAC 572' rootstocks under tropical conditions in Brazil. The highest concentration of bioactive compounds was found in skins of 'BRS Violeta', followed by 'IAC 138-22 Máximo', both grafted onto 'IAC 766'. There was a strong correlation between phenolic content and antioxidant properties, since antioxidant activity also decreased in the sequence: 'BRS Violeta' > 'IAC 138-22 Máximo' > 'BRS Cora' > 'BRS Carmem' > 'Isabel Precoce'. Skin from hybrid grapes ('BRS Violeta', 'IAC 138-22 Máximo', 'BRS Cora' and 'BRS Carmem') grafted in both rootstocks contains higher levels of (poly)phenolic compounds and antioxidant activity than 'Isabel Precoce' (V. labrusca). Skin from 'BRS Violeta' grafted onto 'IAC 766' stand out from the others due to their high content of bioactive compounds.

Whole, concentrated and reconstituted grape juice: Impact of processes on phenolic composition, "foxy" aromas, organic acids, sugars and antioxidant capacity.

The concentration and reconstitution processes of grape juices can result in losing compounds associated with beverage quality. In this context, three tanks containing 50,000 L of grape juice were individually concentrated up to 68 °Brix using a triple vacuum concentrator. The concentrated juice was reconstituted up to the original °Brix of the whole juice (18.4). Phenolic compounds, sugars and organic acids were quantified by high-performance-liquid-chromatography. "Foxy" aromatic compounds were also quantified by gas-chromatography/mass-spectrometry. The concentration and reconstitution process resulted in significant losses (Tukey test, p < 0.01) of trans-caftaric acid, decreasing from 397.08 to 159.14 mg/L, chlorogenic-acid from 34.97 to 8.44 mg/L, aromatic furaneol compound from 9.06 to 1.93 mg/L, as well as total losses for gallic-acid, caffeic-acid, p-coumaric-acid, syringic-acid, hesperidin, pelargonidin-3-glucoside and epicatechin compounds. The concentration and reconstitution of grape juice preserved the antioxidant capacity and most of the quantified compounds, with the reconstituted juice having good nutritional quality.

Digital image-based tracing of geographic origin, winemaker, and grape type for red wine authentication.

This work proposes the development of a simple, fast, and inexpensive methodology based on color histograms (obtained from digital images), and supervised pattern recognition techniques to classify red wines produced in the São Francisco Valley (SFV) region to trace geographic origin, winemaker, and grape variety. PCA-LDA coupled with HSI histograms correctly differentiated all of the SFV samples from the other geographic regions in the test set; SPA-LDA selecting just 10 variables in the Grayscale + HSI histogram achieved 100% accuracy in the test set when classifying three different SFV winemakers. Regarding the three grape varieties, SPA-LDA selected 15 variables in the RGB histogram to obtain the best result, misclassifying only 2 samples in the test set. Pairwise grape variety classification was also performed with only 1 misclassification. Besides following the principles of Green Chemistry, the proposed methodology is a suitable analytical tool; for tracing origins, grape type, and even (SFV) winemakers.

Bioactive compounds in wines produced in a new area for vitiviniculture in Brazil / Compostos bioativos em vinhos produzidos em nova área de vitivinicultura no Brasil

Wines are known for its high content of bioactive compounds that can be influenced by the region and climate where the grapes are produced. New regions of production are normally developed using techniques and standards for other traditional regions, but is important to characterize the wine profile, which is different according to the terroir, and can be important for future geographic indications. The aim of this study was to evaluate color, antioxidant activity, anthocyanin content and phenolic compounds profile in wines produced in Minas Gerais State, Brazil. Wines were produced in different wineries of the same region using the varieties Syrah, Merlot, Cabernet Sauvignon, Cabernet Franc (red), Chardonnay and Sauvignon Blanc (white) and Syrah (rose), from municipalities of Cordislândia, Boa Esperança and Três Corações, located in the south of Minas Gerais State, Brazil. Wines produced in Minas Gerais State presented contents of t-resveratrol, total phenolics, anthocyanins, flavonols, flavanols and phenolic acids consistent to the contents observed in wines from traditional regions of production. However, the terroir and the grape variety can result in a differentiation of compounds observed in wines. Syrah red wines produced in Boa Esperança stood out with higher amounts of anthocyanins (24.29 mg L-1), phenolic acids (123,19 mg L-1 ) and flavonols (35.55 mg L-1), when compared to wines from the same variety from other municipalities and other evaluated red wines. Sauvignon Blanc wines from Boa Esperança presented higher contents of phenolic acids and total flavonols, when compared to wines of the same variety produced in Cordislândia. Chardonay wines presented higher total phenolics content, when compared to ohther evaluated white wines. Rose wine produced in the South of Minas Gerais presented the phenolic acids content of 36,33 mg L-1 and total flavonols content of 29,7 mg L-1. The highest antioxidant activity using the DPPH method, (% of free radicals scavenging - FRS) was observed for Syrah wines from Três Corações, (75.37%), but not different from Cabernet Sauvignon wines from Cordislândia (72.50%), values that can be correlated with the largest content of phenolics observed in wines as phenolic compounds (3009 mg L-1). No differences were observed in the contents of the antioxidant activity of white wines. This results indicate that the studied wines present the necessary nutritional and beneficial characteristics to compete in the supply of bioactive compounds during consumption, when compared to wines produced in traditional and different regions in Brazil and other countries.

Vinhos são conhecidos por seu alto teor de compostos bioativos, os quais podem ser influenciados pela região e clima de cultivo das uvas. Novas regiões de produção são normalmente desenvolvidas utilizando técnicas padrões estabelecidos em regiões produtoras tradicionais, mas é importante a caracterização do perfil do vinho obtido, que é diferente de acordo com o terroir e pode ser importante em futuras indicações geográficas. O objetivo do presente estudo foi avaliar a cor, capacidade antioxidante, teor de antocianinas e perfil de compostos fenólicos em vinhos produzidos no estado de Minas Gerais, Brazil. Vinhos foram produzidos em diferentes vinícolas do estafo utilizando as variedades Syrah, Merlot, Cabernet Sauvignon, Cabernet Franc (tintos), Chardonnay e Sauvignon Blanc (brancos) e vinhos Syrah (rose) roses dos municípios de Cordislândia, Boa Esperança e Três Corações, localizados no sul de Minas Gerais. Vinhos produzidos no estado de Minas Gerais apresentaram teores de t-resveraatrol, fenólicos totais, antocianinas, flavonóis, favanois e ácidos fenólicos consistentes com os observados em vinhos de outras regiões produtoras. No entanto, o terroir e a variedade de uva podem resultar em uma diferenciação de compostos observados em vinhos. Vinhos Syrah produzidos em Boa Esperança se destacaram com altos teores de antocianinas (24.29 mg L-1), ácidos fenólicos (123.19 mg L-1) and flavanois (35.55 mg L-1), quando comparados com vinhos da mesma variedade de outros municípios e os demais vinhos tintos avalaidos. Vinhos Sauvignon Blanc de Boa Esperança apresentaram altos tores de ácidos fenólicos e flavonoids totais, quando comparados com vinhos da mesma variedade produzidos em Cordislândia. Vinhos Chardonay apresentaram maiores teores de fenólicos totaisquando comparados com outros vinhos brancos avaliados. Vinhos Rosé produzidos no Sul de Minas Gerais apresentaram teores de ácidos fenólicos de 36.33 mg L-1 e toeres de flavonois totais de 29.7 mg L-1. Maior atividade antioxidante pelo método do DPPH (% de sequestro de radicais livres) foi observada em vinhos Syrah produzidos em Três Corações (75.37%), não se diferenciando de vinhos Cabernet Sauvignon de Cordislândia (72,50%), teores que podem ser correlacionados com o maiores tores de de fenólicos em vinhos, na forma de compostos fenólicos (3009 mg L-1).Não foram observadas diferenças nos teores de atividade antioxidante em vinhos brancos. Os resultados indicam que os vinhos de Minas Gerais paresental características nutricionais e benéficas indicadas no consume, quando comparados com vinhos produzidos em tradicionais e diferentes regiões do Brasil e outros países.

Processing methods with heat increases bioactive phenolic compounds and antioxidant activity in grape juices.

In this work, the influence of the method of processing on phenolic composition and the in vitro antioxidant activity (AOX) of grape juices was studied. The classic methods of producing "Hot Press" (HP), "Hot Break" (HB), and "Cold Press" (CP), and an artisanal method using steam were compared. Among the methods of elaboration of evaluated grape juices, those that heated the grape showed higher content of bioactive phenolics and AOX. The artisanal method using steam presented acceptable bioactive content and could be simple alternative for grape juice production. The main bioactive compounds quantified in the studied juices were procyanidin B1, quercetin-3-pyranoside, chlorogenic acid, malvidin-3-glucoside, cyanidin-3-glucoside, and petunidin-3-glucoside. These were correlated by principal component analysis (PCA) with the antioxidant activity. The characteristics obtained from the different juice elaboration methods demonstrate that the HB method was responsible for the greatest extraction of bioactive compounds from the grapes. PRACTICAL APPLICATIONS: Worldwide consumption of grape juice has been increasing. The factors that have contributed to this growth include the good sensory acceptance and the nutritional appeal related to bioactive compounds. The bioactive compounds of grape juice are mainly flavonoids and phenolic acids, and several factors exert influence on the phenolic composition of this beverage, among them, the method of elaboration. The present work presents new information on the influence of grape juice processing methods on the profile of bioactive compounds of nutritional interest and contributes to improvements in the production processes of this beverage.

Climate effects on physicochemical composition of Syrah grapes at low and high altitude sites from tropical grown regions of Brazil.

The major areas of the world where viticulture is practiced enjoy temperate or cool temperature climates. When wine grapes are grown in tropical regions, edaphoclimatic factors result in distinct grape quality attributes, and production techniques also require significant adjustment. The objective of this study was to characterize the chemical compositions, in particular of phenolic compounds, of Syrah grapes grown in two location in northeast Brazil - these are also at widely different altitudes. A range of methods of phenolic extraction were used, along with classical chemical analyses including for organic acids, sugars, monomeric anthocyanins, flavonols, stilbene, condensed tannins and some of the monomeric and small oligomeric procyanidins. The regions and their diverse environments had a larger influence than harvest year. The grapes at higher altitude (Bahia, 1.100 m asl (metres above sea level) were characterized by higher levels of malic acid, anthocyanins and condensed tannins in the skins. The low-altitude grapes (Pernambuco, 350 m asl (metres above sea level) had higher levels of glucose, fructose, 3-O-acetylglucoside anthocyanins and condensed tannins in the seeds. Fruit composition was highly influenced by the region. In the low-altitude region, the grapes were characterized by higher tartaric and citric acid in the must, also of flavonols in skins and of tannins in the seeds. Meanwhile, the fruit from the high altitude, contained higher levels of malic and succinic acid in the must, and of anthocyanins and condensed tannins in the skins.

Grape juices produced from new hybrid varieties grown on Brazilian rootstocks - Bioactive compounds, organic acids and antioxidant capacity.

The objective of this study was to assess the content of bioactive compounds, organic acids and antioxidant capacity of grape juices from Isabel Precoce, BRS Carmem, BRS Cora and IAC 138-22 Máximo varieties grown on the 'IAC 766' and 'IAC 572' rootstocks under tropical conditions in Brazil. In general, the color attributes of the 'Isabel Precoce' juice were inferior to those of the other juices due to their low anthocyanin content. In contrast, 'IAC 138-22 Máximo' juices showed the highest content of most individual anthocyanins, flavonols, trans-resveratrol and total phenolic compounds, and thus, higher antioxidant capacity. Except for 'BRS Carmem', all the juices presented higher sugar accumulation when 'IAC 766' was used. This rootstock also contributed to the accumulation of t-resveratrol and most of individual anthocyanins in the 'IAC 138-22 Máximo' juices. However, the monomeric anthocyanin content was higher in 'BRS Carmem' juices when 'IAC 572' rootstock was used.

Chemical characteristics of grapes cv. Syrah (Vitis vinifera L.) grown in the tropical semiarid region of Brazil (Pernambuco state): influence of rootstock and harvest season.

BACKGROUND: Obtaining two or more successive annual vintages from the same vineyard is characteristic of regions with a tropical climate, such as the Submédio of the São Francisco Valley, Brazil. The present study aimed to characterize the chemical composition of grapes in four production cycles (i.e. two calendar years) when considering the interaction between cv. Syrah and two rootstocks. For a broad characterization, two methodologies for the extraction of phenolic compounds were used, as well as different methods of analysis. RESULTS: The results obtained showed that there was an influence of rootstock and harvest season. Grapes from vines grafted onto IAC 313 contained higher concentrations of total condensed tannins (skins) and flavanols than grapes from vines grafted onto 1103P. However, the grape samples from the vines grafted onto 1103P contained higher levels of monomeric anthocyanins than the grape samples from the vines grafted onto IAC 313. The first harvest season was characterized by higher concentrations of most phenolic compounds than the second harvest season. CONCLUSION: In the present study, it was possible to confirm that, in the semiarid region of Brazil, the interaction between the cultivar Syrah and the different rootstocks, as well as the climatic conditions in each harvest season, influenced the composition of the grapes, mainly in relation to phenolic compounds. © 2019 Society of Chemical Industry.

Integrated analyses of phenolic compounds and minerals of Brazilian organic and conventional grape juices and wines: Validation of a method for determination of Cu, Fe and Mn.

The phenolic profile and antioxidant activity (AOX) of "organic vs. conventional" Brazilian wines and grape juices were analyzed. A simple method for the determination of minerals Cu, Fe and Mn by F-AAS was validated and used to characterize the samples studied. In the validation of the Cu, Fe and Mn determination method, the protocol for samples preparation by hot digestion with HNO3 + H2O2 proved to be more suitable for the grape juice and wine matrices. The validation parameters were considered satisfactory. Conventional products presented higher anthocyanins content, and no significant differences were observed on other phenolic compounds, AOX and Cu, Fe and Mn minerals. All the evaluated samples presented similar results between the same cultivars and in products from grapes of the two cultivation systems. The AOX of juices and wines, organic and conventional, was high, and correlated with procyanidin B1, petunidin-3-glucoside and cyanidin-3,5-diglucoside.

Rapid determination of the aromatic compounds methyl-anthranilate, 2'-aminoacetophenone and furaneol by GC-MS: Method validation and characterization of grape derivatives.

A methodology for the rapid determination of the aromatic compounds methyl anthranilate (MA), 2'-aminoacetophenone (2-AAP) and furaneol by GC-MS was validated and used to characterize grape juice and wine elaborated with the new Brazilian grape varieties cultivated in northeastern Brazil, and Brazilian grape nectars. The method presented linearity (R2 ˃ 0.9952), good accuracy (CV < 12.9%), recovery (76.6% to 106.3%), limit of detection (23 µg L-1 to 94 µg L-1) and limit of quantification (96 µg L-1 to 277 µg L-1) acceptable in only 20 min of running. The methodology was considered satisfactory for the purpose, being a simple and rapid method for the determination of these compounds in grape derivatives drinks. In the characterization of the nectars the compound that stood out was the MA, being its presence attributed to the addition of flavorings in these products. It was evidenced a significant contribution of furaneol in the aroma of grape juice and wines elaborated with the new Brazilian grape varieties.

Rapid determination of flavonoids and phenolic acids in grape juices and wines by RP-HPLC/DAD: Method validation and characterization of commercial products of the new Brazilian varieties of grape.

A method for rapid determination of phenolic compounds by reversed-phase high-performance liquid chromatography (RP-HPLC), using a new column of faster resolution was validated and used to characterize commercial products produced with new grape Brazilian varieties of Northeast of Brazil. The in vitro antioxidant activity was also measured. The method showed linearity (R>0.9995), good precision (CV%<2.78), recovery (91.8-105.1%) and limits of detection (0.04-0.85mgL-1) and quantification (0.04-1.41mgL-1) according to other methods previously published with the difference of a run time of only 25min. The results obtained in the characterization of the samples differed for juices and wines from other world regions, mainly because of the high values of (-)-epigallocatechin and trans-caftaric acid. The products analyzed showed high antioxidant activity, especially the wine samples with values higher than those from wines of different regions of the world.

Influence of physical and chemical characteristics of wine grapes on the incidence of Penicillium and Aspergillus fungi in grapes and ochratoxin A in wines.

The incidence of filamentous fungi and toxin levels in grapes and wines varies depending on the variety of grapes, the wine region, agricultural practices, weather conditions, the harvest and the winemaking process. In this sense, the objective of this study was to evaluate the diversity of Aspergillus and Penicillium fungi isolated from wine grapes of the semi-arid tropical region of Brazil, evaluate the presence of ochratoxin A (OTA) in the experimental wine and verify if there is a correlation between occurrence of these fungi and the physicochemical characteristics of the wine grapes grown in the region. For the isolation of fungi we used the direct plating technique. The presence of OTA in the experimental wine was detected by high-performance liquid chromatography. The species found were Aspergillus niger, A. carbonarius, A. aculeatus, A. niger Aggregate, A. flavus, A. sojae, Penicillium sclerotiorum, P. citrinum, P. glabrum, P. decumbens, P. solitum and P. implicatum. All isolates of A. carbonarius were OTA producers and all P. citrinum were citrinin producers. The highest concentration of OTA was found in red wine (0.29µg/L). All species identified in this study, except A. flavus, showed a positive correlation with at least one physicochemical parameter assessed, highlighting the pectin content, total sugar, total acidity and phenolic compounds.

Bioactive compounds of juices from two Brazilian grape cultivars.

BACKGROUND: Grape juice consumption may prevent several chronic diseases owing to the presence of phenolic compounds, which have an important role in the reduction of oxidative stress. This study investigated the polyphenol content and antioxidant activities of grape juices from two cultivars: BRS-Cora and Isabella. Total polyphenol content (TPC), anthocyanins, antioxidant capacity (oxygen radical absorbance capacity, ferric reducing antioxidant power and 1,1-diphenyl-2-picrylhydrazyl), and phenolic profile (high-performance liquid chromatography with diode array and fluorescence detection--HPLC-DAD-FLD) were determined. RESULTS: BRS-Cora grape juice showed higher concentrations of total polyphenols and anthocyanins, as well as higher antioxidant potential, than those of Isabella grape juice. A significant positive correlation was found in TPC or anthocyanin contents when correlated with the remaining antioxidant assays. In addition, HPLC-DAD-FLD showed a higher total phenolic content in BRS-Cora grape juice compared to Isabella. CONCLUSION: The present results show BRS-Cora as a promising cultivar for grape juice production with an improved functional potential.

Phenolic compounds, organic acids and antioxidant activity of grape juices produced in industrial scale by different processes of maceration.

The effect of maceration process on the profile of phenolic compounds, organic acids composition and antioxidant activity of grape juices from new varieties of Vitis labrusca L. obtained in industrial scale was investigated. The extraction process presented a high yield without pressing the grapes. The use of a commercial pectinase resulted in an increase on extraction yield and procyanidins B1 and B2 concentrations and a decrease on turbidity and concentration of catechins. The combination of 60 °C and 3.0 mL 100 kg(-1) of enzyme resulted in the highest extraction of phenolic compounds, reducing the content of acetic acid. The juices presented high antioxidant activity, related to the great concentration of malvidin, cyanidin, catechin and caffeic, cinnamic and gallic acids. Among the bioactive compounds, the juices presented high concentration of procyanidin B1, caffeic acid and trans-resveratrol, with higher levels compared to those reported in the literature.

Winery by-products: extraction optimization, phenolic composition and cytotoxic evaluation to act as a new source of scavenging of reactive oxygen species.

Nearly 20 million tons of winery by-products, with many biological activities, are discarded each year in the world. The extraction of bioactive compounds from Chenin Blanc, Petit Verdot, and Syrah grape by-products, produced in the semi-arid region in Brazil, was optimized by a Central Composite Rotatable Design. The phenolic compounds profile, antioxidant capacity against synthetic free radicals (DPPH and ABTS), reactive oxygen species (ROS; peroxyl radical, superoxide radical, hypochlorous acid), cytotoxicity assay (MTT) and quantification of TNF-α production in RAW 264.7 cells were conducted. Gallic acid, syringic acid, procyanidins B1 and B2, catechin, epicatechin, epicatechin gallate, quercetin 3-ß-d-glucoside, delfinidin 3-glucoside, peonidin 3-O-glucoside, and malvidin 3-glucoside were the main phenolic compounds identified. In general, rachis showed higher antioxidant capacity than pomace extract, especially for Chenin Blanc. All extracts showed low cytotoxicity against RAW 264.7 cells and Petit Verdot pomace suppressed TNF-α liberation in vitro. Therefore, these winery by-products can be considered good sources of bioactive compounds, with great potential for application in the food and pharmaceutical industries.

Phenolic compounds, organic acids and antioxidant activity of grape juices produced from new Brazilian varieties planted in the Northeast Region of Brazil.

The phenolic compounds, organic acids and the antioxidant activity were determined for grape juice samples from new Brazilian varieties grown in the Sub-middle São Francisco Valley in the Northeast Region of Brazil. The results showed that the Brazilian grape juices have high antioxidant activity, which was significantly correlated with the phenolic compounds catechin, epicatechin gallate, procyanidin B1, rutin, gallic acid, caffeic acid, p-coumaric acid, pelargonidin-3-glucoside, cyanidin-3-glucoside, cyaniding-3,5-diglucoside and delphinidin-3-glucoside. The produced juice samples showed higher concentrations of trans-resveratrol than those observed in juices made from different varieties of grapes from traditional growing regions. Organic acids concentrations were similar to those of juices produced from other classical varieties. It was demonstrated that it is possible to prepare juices from grapes of new varieties grown in the Northeast of Brazil containing a high content of bioactive compounds and typical characteristics of the tropical viticulture practised in the Sub-middle São Francisco Valley.

Composição fenólica e atividade antioxidante de resíduos agroindustriais / Phenolic composition and antioxidant activity of agroindustrial residues

Atualmente, são produzidas milhões de toneladas de resíduos provenientes do processamento agroindustrial. Muitos deles são ricos em compostos bioativos sendo potenciais fontes naturais dessas substâncias. Assim, este trabalho teve como objetivo avaliar o teor de compostos fenólicos totais, a atividade antioxidante e a composição fenólica de três resíduos gerados por agroindústrias brasileiras: bagaço de uva Isabel (BI) (Vitis labrusca), bagaço de uva Verdejo (BV) (Vitis vinifera) e bagaço de goiaba (BG) (Psidium guajava). Os resultados do teor de compostos fenólicos totais (mg GAE g-1) encontrados nos extratos etanólicos e aquosos dos resíduos foram, respectivamente: BV (20,94±0,46; 8,03±0,43)> BI (16,57±0,19; 4,41±0,01)> BG (3,41±0,09; 1,88±0,06). Alta atividade antioxidante, principalmente em BV e BI, foi verificada nos ensaios realizados (ABTS ●, DPPH ● e auto-oxidação do sistema beta-caroteno/ácido linoléico). Uma forte correlação positiva entre atividade antioxidante e o teor de compostos fenólicos totais foi encontrada. Os compostos fenólicos encontrados, por cromatografia gasosa com espectrometria de massas (CG-EM), foram: ácido gálico, epicatequina, quercetina (BV, BI e BG); ácido isovanílico (BI, BG); ácido p-cumárico (BI); ácido caféico e resveratrol (BV, BI). Esses resultados mostram que os resíduos agroindustriais analisados, particularmente os vinícolas, são ricos em substâncias bioativas e podem ser explorados pela indústria de alimentos e farmacêutica.

Nowadays, the agro-industrial processing produces millions of tons of wastes. Many of them are rich in bioactive compounds, being a potential natural source of these substances. This study aimed to evaluate the content of total phenolics, antioxidant activity and phenolic composition of residues generated by three Brazilian agribusiness: Isabel grape pomace (PI) (Vitis labrusca), Verdejo grape pomace (PV) (Vitis vinifera) and guava pomace (PG) (Psidium guajava). The results of total phenolics content (mg GAE g-1) found in the ethanol and aqueous extracts of residues were: PV (20.94±0.46; 8.03±0.43)>PI (16.57±0.19; 4.41±0.01)>PG (3.41±0.09; 1.88±0.06). High antioxidant activity of these extracts, particularly PV and PI, was found by the methods DPPH ●, ABTS ● and beta-carotene bleaching method. A strong positive correlation between antioxidant activity and content of total phenolic compounds was found. The following phenolic compounds were found by gas chromatography with mass spectrometry (GC-MS): gallic acid, epicatechin, quercetin (PV, PI and PG); isovanilic acid (PI, PG), p-coumaric acid (PI), caffeic acid and resveratrol (PV, PI). The results show that these residues, particularly the wineries, are rich in bioactive substances and should be exploited by the food industry and pharmaceuticals.

Avaliação do potencial de cinco cultivares de videiras americanas para sucos de uva no sul de Minas Gerais / Potential evaluation of five american cultivars for grape juices in the south of Minas Gerais state

Objetivou-se, no presente trabalho realizar uma caracterização dos sucos de uva de cinco cultivares de videira americana Vitis labrusca (Folha de Figo, Alwood, Concord, BRS-Rúbea e Isabel) segundo suas características visuais, olfativas e gustativas, utilizando um método descritivo por um painel de degustadores da Embrapa Uva e Vinho (EMBRAPA/CNPUV) de Bento Gonçalves e da Associação Brasileira de Enologia (ABE), constituído por doze degustadores. De acordo com os resultados, os sucos das cultivares Isabel e Folha de Figo foram superiores aos demais, segundo a análise de componentes principais (ACP), principalmente pelas variáveis limpidez, equilíbrio olfativo, intensidade e corpo gustativo, persistência olfato-gustativa e julgamento geral (notas). O suco Folha de Figo foi superior ao Isabel quanto à tonalidade, sendo o primeiro caracterizado como vermelho-violáceo. A cultivar Folha de Figo é a mais utilizada na região para a produção de suco, podendo os produtores utilizarem também a cultivar Isabel, que mostrou potencial nas condições edafo-climáticas do sul de Minas Gerais.

The present work was designed to accomplish the characterization of the different grape juices of five grapevine cultivars of Vitis labrusca (Folha de Figo, Alwood, Concord, BRS-Rúbea e Isabel) according to their visual, smell and taste characteristics utilizing a descriptive method by a panel of tasters of Embrapa Grape and Wine (EMBRAPA/CNPUV) of Bento Gonçalves, and of the Brazilian Enology Association (ABE) consisting of 12 tasters. According to the results, the juices of the cultivars Isabel and Folha de Figo were higher than the others, analyzed statistically according to the Principal Component Analysis (PCA), mainly by the visual cleanliness variables, olfatory equilibrium, gustative body and quality, olfato-gustative persistence and general judgement (scores) and the juice of Folha de Figo was higher than Isabel according to visual shade, the former being characterized as violet-red. Folha de Figo is the most used cultivar for grape juices. Isabel would be also used, with a great potential in the environmental conditions of the south of Minas Gerais estate.