The effects of homogenisation method and freezing on the determination of quality parameters in red grape berries of Vitis vinifera

The effect of sample processing with three different blenders, sample freezing and storage time on the determination of berry quality parameters – total anthocyanins, total soluble solids (TSS), total phenolics (TP) and pH – in homogenates of red grape berries has been examined. Samples of Cabernet Sauvignon, Merlot and Shiraz from four regions of South Australia were homogenised using Ultra-Turrax, Waring or Retsch commercial blenders applied to fresh samples, and to samples held in frozen storage overnight or for 1, 3, 6 and 12 months. All samples were analysed immediately after homogenisation. The results showed that neither homogeniser type nor freezing had any significant effect on total anthocyanins or TSS. However, freezing had an effect on total anthocyanins concentrations in samples with higher colour. The homogeniser type had a significant effect on TP and pH for all varieties analysed together. Freezing had no significant effect on TP, but significant effect on pH, the value being greater in samples at the lower end of the pH range. Frozen storage time of up to 3 months had no significant effect on total anthocyanins, TSS or T P. Statistically significant differences were observed in the concentration of total anthocyanins in samples after 3 months of frozen storage.     

Anthocyanin profile of Spanish Vitis vinifera L. red grape varieties in danger of extinction

This paper reports on a study of the anthocyanin fraction in berry skins of ten minority red and pink grapevine varieties from Castilla-La Mancha (Spain) and two traditional varieties from this growing region, Tempranillo and Garnacha Tinta, as references. These varieties were correctly identified beforehand by analysing six microsatellite regions recommended by the GENRES 081 project; five varieties were identified with genotypes identical to those described previously, and five new genotypes not described for any variety according to the literature consulted. Grape skin extracts of each variety were analysed by HPLC-UV-Vis, and four perfectly differentiated anthocyanin profiles were obtained. In six out of ten varieties (Churriago, Unknown 1, Unknown 2, Ariño, Brujidera and Moravia Agria) the major anthocyanin was malvidin-3-glucoside (39%). Tinto Velasco contained more than 29% delphinidin-3-glucoside, Gordera Roja and Teta de Vaca Tinta more than 40% peonidin-3-glucoside, and Rojal more than 29% cyanidin-3-glucoside. Results of this work point out the existence of unusual anthocyanic profiles in several of these indigenous varieties, and highlight the necessity of studying the effects of variety on other flavonoids and their impact on wine colour.     

Polyphenolic composition of Spanish red wines made from Spanish Vitis vinifera L. red grape varieties in danger of extinction

Phenolic composition, chromatic characteristics, and antioxidant activity of young wines made from three minority red grape varieties (Moravia Dulce, Rojal and Tortosí) cultivated in the Spanish region of Castilla-La Mancha were studied over two vintages. Phenolic contents were affected by both grape variety and vintage, whereas phenolic profiles were mainly affected by grape cultivar, thus allowing their differentiation The anthocyanin profiles of Moravia Dulce and Tortosí wines were dominated by malvidin 3-glucoside, whereas peonidin 3-glucoside was in Rojal wines. The flavonol profile of Rojal and, in a lesser extent, Tortosí wines were dominated by B-ring di-substituted flavonols (mainly quercetin-type flavonols). In contrast, B-ring tri-substituted flavonols (mainly myricetin-type) predominated in Moravia Dulce wines. All studied wines had high quantities of total resveratrol, especially Rojal and Moravia Dulce wines, although they mainly occurred as cis-isomers. Rojal wines always appeared as the most different single-cultivar wines in all parameters in this study, being characterized by the lowest content of almost all families of phenolic compounds. With regard to the colour characteristics, all the studied wines had normal values to be considered young red wines except for Rojal wines, which should be considered as rosé wines. Finally, all wines showed remarkable antioxidant activity, closely connected with their phenolic content. The results suggest that Moravia Dulce and Tortosí grape cultivars could be appropriate raw materials for the elaboration of quality young red wines, whereas Rojal grapes could be for rosé wines.     

Vine performance and grape composition as affected by early-season source limitation induced with anti-transpirants in two red Vitis vinifera L. cultivars

Background and Aims: Previous work has shown that an early (i.e. pre-flowering) source limitation achieved with either hand or mechanical basal shoot zone defoliation is effective in controlling yield while improving grape composition in several environments and Vitis vinifera genotypes. Our study was designed to determine whether similar results can be reproduced by using a film-forming anti-transpirant. Methods and Results: The entire canopies of field grown cvs. Sangiovese and Ciliegiolo vines were treated twice pre-flowering with the anti-transpirant Vapor Gard® (Intrachem Bio Italia, Grassobbio, BG, Italy) (T) and compared with an unsprayed control (C). Leaf assimilation and transpiration in both cultivars showed similar reductions (30–70%) for several weeks after spraying as compared with control vines, while intrinsic water use efficiency increased in treated vines soon after first application and after veraison. In Sangiovese, treated vines showed reduced yield, berry weight, bunch compactness and, on a 2-year basis, lower vigour and unchanged vine capacity every year. At harvest, treated vines showed higher °Brix in all seasons and higher anthocyanin concentration in 2 out of 3 years. Results of a 2-year run in Ciliegiolo mimicked those of Sangiovese in terms of yield regulation. Conclusions: Early season applications of a film-forming anti-transpirant caused a leaf function limitation strong enough to reduce yield and bunch compactness through smaller final berry size. Significance of the Study: Anti-transpirant applications can be proposed as a much easier way than manual or mechanical leaf removal to induce crop regulation through early source limitation.     

Aroma characterization of red wines from cv. Bobal grape variety grown in La Mancha region

Bobal is an indigenous Spanish cultivar, principally grown in the region of Valencia. The volatile composition of young red wines made from the cv. Bobal grape variety grown in the La Mancha region of Spain has been studied over five vintages by instrumental analysis to determine the influence of grape variety on the aroma of wine. Free and glycosidically-bound aroma compounds were isolated by solid phase extraction (SPE) using dichloromethane and ethyl acetate respectively to later be analyzed using gas chromatography-mass spectrometry (GC/MS). One hundred and twelve (112) free aroma compounds and ninety-six (96) bound aroma compounds were identified and quantified in Bobal wines oven this five year period. Based on the result, Bobal wine presents a complex chemical profile with a wealth of aromas in its aromatic composition.     

The role of red and processed meat in colorectal cancer development: a perspective

This paper is based on a workshop held in Oslo, Norway in November 2013, in which experts discussed how to reach consensus on the healthiness of red and processed meat. Recent nutritional recommendations include reducing intake of red and processed meat to reduce cancer risk, in particular colorectal cancer (CRC). Epidemiological and mechanistic data on associations between red and processed meat intake and CRC are inconsistent and underlying mechanisms are unclear. There is a need for further studies on differences between white and red meat, between processed and whole red meat and between different types of processed meats, as potential health risks may not be the same for all products. Better biomarkers of meat intake and of cancer occurrence and updated food composition databases are required for future studies. Modifying meat composition via animal feeding and breeding, improving meat processing by alternative methods such as adding phytochemicals and improving our diets in general are strategies that need to be followed up.     

Diversity of Saccharomyces and non-Saccharomyces yeasts in three red grape varieties cultured in the Serranía de Ronda (Spain) vine-growing region

For the first time, an ecological survey of wine yeasts present in grapes growing in two vineyards located in the region of “Serranía de Ronda” (Málaga, southern Spain) has been carried out. During the 2006 and 2007 vintages, grapes from different varieties were aseptically collected and allowed to ferment spontaneously in the laboratory. From a total of 1586 colonies isolated from microvinifications, 1281 were identified according to ITS polymorphisms and their identity confirmed by sequencing of the D1/D2 region of 26S rDNA. Most of the isolates (84%) corresponded to thirteen different non-Saccharomyces species with Kluyveromyces thermotolerans, Hanseniaspora guilliermondii, Hanseniaspora uvarum and Issatchenkia orientalis accounting for 42.7% of the total. Mitochondrial DNA restriction analysis from the Saccharomyces cerevisiae isolates revealed a low diversity since only eleven different profiles were found, nine of them corresponding to local strains and two to commercial ones that had been used in different campaigns and that very likely were disseminated from the winery to the adjacent vineyard. A different distribution of strains was found in the three grape varieties studied.     

The role of gluten in a pound cake system: A model approach based on gluten–starch blends

In order to evaluate the role of gluten in cake-making, gluten–starch (GS) blends with different ratios of gluten to starch were tested in a research pound cake formula. The viscosities of batters made from commercial GS blends in the otherwise standardised formula increased with their gluten content. High viscosities during heating provide the batters with the capacity to retain expanding air nuclei, and thereby led to desired product volumes. In line with the above, increasing gluten levels in the cake recipes led to a more extended oven spring period. Cakes with a starch content exceeding 92.5% in the GS blend suffered from substantial collapse during cooling. They had a coarse crumb with a solid gummy layer at the bottom. Image analysis showed statistical differences in numbers of cells per cm², cell to total area ratio and mean cell area (p < 0.05). Both density and mean cell area were related to gluten level. Moreover, mean cell area and cell to total area ratio were the highest for cakes with the lowest density and highest gluten levels. Relative sodium dodecyl sulfate (SDS, 2.0%) buffer (pH 6.8) extractabilities of protein from cakes baked with the different GS blends decreased with gluten content and were strongly correlated with the intensity of collapse. Taken together, the results teach that protein gives the cakes resistance to collapse, resulting in desirable volumes and an optimal grain structure with uniform cell distribution.     

The impact of dietary oil source and frozen storage on the physical,chemical and sensorial quality of fillets from market-size red hybrid tilapia, Oreochromis sp.

Red hybrid tilapia (Oreochromis sp.) were fed one of four diets containing either fish oil, crude palm oil, palm fatty acid distillates or refined palm olein as the only added oil. Post-harvest fillet quality was then evaluated at 1, 10 and 30 weeks of frozen storage. Dietary oil source did not significantly (p > 0.05) influence the liquid holding capacity and texture of fillets but both these parameters were increased by frozen storage. Fillets from fish fed palm oil-based diets exhibited significantly higher oxidative stability during frozen storage, compared to fish fed the fish oil diet. Dietary oil source and frozen storage had little impact on sensory attributes. Unlike fillet proximate composition, fillet fatty acid composition was significantly affected by both diet and frozen storage. Total n-3 polyunsaturated fatty acids decreased significantly in the fillet lipids of all fish after 30 weeks of frozen storage.     

New processes in the environmental chemistry of nitrite. 2. The role of hydrogen peroxide

The oxidation of nitrite and nitrous acid to *NO2 upon irradiation of dissolved Fe(III), ferric (hydr)oxides, and nitrate has previously been shown to enhance phenol nitration. This allowed the proposal of a new role for nitrite and nitrous acid in natural waters and atmospheric aerosols. This paper deals with the interaction between hydrogen peroxide, a key environmental factor in atmospheric oxidative chemistry, and nitrite/nitrous acid. The reaction between nitrous acid and hydrogen peroxide yields peroxynitrous acid, a powerful nitrating agent and an important intermediate in atmospheric chemistry. The kinetics of this reaction is compatible with a rate-determining step involving either H3O2+ and HNO2 or H2O2 and protonated nitrous acid. In the former case the rate constant between the two species would be 179.6 +/- 1.4 M(-1) s(-1), in the latter case it would be as high as (1.68 +/- 0.01) x 10(10) M(-1) s(-1) (diffusion-controlled reaction). Due to the more reasonable value of the rate constant, the reaction between H3O2+ and HNO2 seems more likely. In the presence of HNO2 + H2O2 the nitration of phenol is strongly enhanced when compared with HNO2 alone. The nitration rate of phenol in the presence of peroxynitrous acid decreases as pH increases, thus HOONO is a potential source of atmospheric nitroaromatic compounds in acidic water droplets. The mixture Fe(II) + H2O2 (Fenton reagent) can oxidize nitrite and nitrous acid to nitrogen dioxide, which results in phenol nitration. The nitration in the presence of Fe(II) + H2O2 + NO2-/HNO2 occurs more rapidly than the one with H2O2 + NO2-/HNO2 at pH 5, where little HNO2 is available to directly react with hydrogen peroxide. Both systems, however, are more effective than NO2-/HNO2 alone in producing nitrophenols from phenol. Another process leading to the oxidation of nitrite to nitrogen dioxide is the photo-Fenton one. It can be relevant at pH > or = 6, as nitrite does not react with H2O2 at room temperature. Under such conditions the source of Fe(II) is the photolysis of ferric (hydr)oxides (heterogeneous photo-Fenton reaction). In the presence of nitrite this reaction induces very effective nitrophenol formation from phenol.     

Environmental effects on cv Cabernet Sauvignon (Vitis vinifera L.) grown in Hawke's Bay, New Zealand.: 2. Development of a site index

Based on observations of Cabernet Sauvignon phenology, cropping and fruit characteristics at six vineyard sites in Hawke's Bay (New Zealand) studied over three seasons, a numerical model is proposed to characterise environmental conditions of a vineyard site. The proposed model is based on air temperature in October and January, seasonal rainfall, rooting depth, gravel percentage and clay-to-silt ratio in topsoil. The 'Site Index' (SI) calculated from these variables was significantly correlated with soil temperature and volumetric soil moisture content, themselves closely linked with clay-to-silt ratio, air temperature and rainfall. Vegetative growth, canopy characteristics, precocity of veraison, total anthocyanins, TSS and malic acid concentration in grapes, as well as wine sensory score, were all significantly correlated with the SI values at six sites and over two seasons. Over the same period, correlation of SI with several viticultural variables was generally stronger than five existing climatic indices for viticulture calculated for these sites. The proposed SI index appears to have potential use for vineyard zoning and site selection and evaluation.     

The role of a low molecular weight glutenin fraction in the cooking quality of durum wheat pasta

Durum wheat glutenin fractions, composed of two low molecular weight proteins DSG-1 and DSG-2 (durum wheat (Triticum durum Desf) sulphurrich glutenin fractions) were extracted from semolina samples using a low concentration of Na tetradecanoate after extracting albumins, globulins and gliadins. DSG proteins have a high? SH plus S? S content. A highly significant correlation was found between the ? SH plus S? S content of this DSG-rich fraction and the cooking quality of pasta (0.63, P <0.01 with firmness and 0.86, P <0.001 with the state of the surface of the cooked pasta) and this seems to be a functional relationship. The use of acetic acid at various molarities showed the presence of high molecular weight glutenin fractions with differing solubility properties. In this respect, differences were found between varieties which are placed in the same group according to the classification of durum wheats based upon the composition of high molecular weight glutenin subunits.     

The influence of ripeness grade on the composition of musts and wines from Vitis vinifera cv. Tempranillo grown in a warm climate

Fruit ripeness has an influence on the phenolic and aromatic composition of grapes and musts and, therefore, on the sensorial characteristics of the resulting wine. The aim of the work described here was to assess the influence of the harvest date on the analytical composition of the musts and wines from the Vitis vinifera cv. Tempranillo grape grown in a warm climate. A hydroalcoholic medium was employed to extract the musts and simulate a traditional maceration process. Phenolic compounds were analysed by colorimetric methods and aroma compounds by gas chromatography/mass-spectrometry. Furthermore, the wines were tested by a sensory panel. A good correlation was obtained between the parameters measured in the must and in the corresponding wine, as well as in the scores recorded in the sensory analysis. In summary, grape ripening was found to have a marked influence on the wine composition and it was possible to establish the key parameters that need to be measured in the must during ripening to identify the optimal harvest date to obtain the best quality wine.