Evolution of anthocyanins during maturation of tempranillo grape variety (Vitis vinifera) using polynomial regression models

In general, the anthocyanin content of grapes increases during ripening but presents a concentration minimum a few days before physiological maturity. This minimum is sharper for the acyl derivatives. Significant behavioural differences were found between monoglucosides and their acyl derivatives. A polynomial model was used to describe the evolution of anthocyanins in the maturation of Tempranillo grapes (Vitis vinifera L).     

Characterization of Sultaniye grape (Vitis vinifera L. cv. Sultana) polyphenol oxidase

Polyphenol oxidase (PPO) was extracted from Sultaniye grapes grown in Turkey, and its characteristics in terms of pH and temperature optima, thermal inactivation, kinetic parameters and potency of some PPO inhibitors were studied. Optimum pH and temperature for grape PPO were found to be 3.4 and 30 °C, using catechol as substrate. K_m and V_max values were found to be 44.5 ± 5.47 mm and 0.695 ± 0.0353 OD₄₁₀ min^?1, respectively. Four inhibitors were tested in this study and the most potent inhibitor was sodium metabisulphite, followed by ascorbic acid. From the thermal inactivation studies in the range of 65–80 °C, the half‐life values of the enzyme ranged between 2.6 and 49.5 min. Activation energy (E_a) and Z values were calculated to be 208.5 kJ mol^?1 (r² = 0.9544) and 10.95 °C (r² = 0.9517), respectively.     

Antioxidant activity and dietary fibre of Prensal Blanc white grape (Vitis vinifera) by‐products

Stem and pomace of a white grape (Vitis vinifera) variety, Prensal Blanc, were studied for the first time: general composition and dietary fibre components together with the total soluble polyphenol content and antioxidant activity. Both by‐products present high contents of total dietary fibre (TDF), 790 g kg^?1 d.m. (stem) and 716 g kg^?1 d.m. (pomace). Values of the soluble dietary fibres in relation to TDF differed: 5% (stem) and 14.4% (pomace). Similar values of Klason lignin were found: 229 g kg^?1 (stem) and 278 g kg^?1 (pomace), however, the pomace exhibited more than twice the content of the condensed tannins (168 g kg^?1) with regard to the stem (79 g kg^?1). Notable were the high resistant protein contents of both by‐products. Stem and pomace showed appreciable amounts of total soluble polyphenols (87 g kg^?1 against 35 g kg^?1 respectively). The free radical scavenging capacity of the former by‐products was determined using the 2,2‐diphenyl‐1‐picrylhydrazyl radical (DPPH) method, obtaining EC₅₀ values of 0.79 g d.m. g^?1 DPPH (stem) and 1.32 g d.m. g^?1 DPPH (pomace). These data shows that both vinification by‐products from the Prensal Blanc variety are a good source of dietary fibre and have antioxidant properties.     

Antioxidative activities of grape (Vitis vinifera) seed extracts obtained from different varieties grown in Turkey

In this study, total phenolic contents and antioxidant activities of grape seed extracts obtained from twelve different grape seeds from common varieties grown in Turkey were determined. Grape seeds were extracted with 70% acetone and extraction yield of grape seed were calculated. The total phenolic content of grape seed extracts were determined by the Folin‐Ciocalteu procedure and ranged from 33 945 to 58 730 mg per 100 g extract as gallic acid equivalent. Antioxidant activities of grape seed extracts with two different free radical scavenging methods, ABTS [2,2/‐azinobis (3‐ethylbenzothiazoneline‐6‐sulfonic acid)] and DPPH (2,2‐diphenyl‐picrylhydrazyl) assays, using Trolox equivalent as standards, were investigated. Grape seed extracts exhibited antioxidant activities 2.46–4.14 and 3.55–5.76 [Trolox equivalent antioxidant capacities (TEAC) mg^?1 extracts] in ABTS and DPPH assays, respectively. Compared with varieties, Muskule extracts exhibited the lowest total phenolic content, TEAC_ABTS and TEAC_DPPH value while Narince extracts had the highest total phenolic content and TEAC_DPPH value, and Alphonse Lavalleé had the highest TEAC_ABTS value. Total phenolic content showed that there is a significant correlation with TEAC_DPPH (r = 0.7974, P ≤ 0.001) and TEAC_ABTS values (r = 0.4860, P ≤ 0.05).     

Physicochemical characteristics and functional properties of grape (Vitis vinifera L.) seeds protein

The amino acid composition, physicochemical and functional properties of grape (Vitis vinifera L.) seeds protein (GSP) were evaluated and compared with those of soybean protein isolate (SPI). Amino acid analyses of GSP revealed high levels of glutamic/glutamine, glycine and aspartic/asparagines. SDS‐PAGE analysis demonstrated that globulin was the major protein component in GSP, whose subunit molecular weights were mainly varied from 25.5 to 40.0 kDa. The isoelectric pH of GSP was found to be at the acidic pH of around 3.8. At all the pHs tested except pH 2.0, no significant changes of GSP secondary structure were observed. GSP exhibited beneficial functional properties such as preferable solubility and emulsifying activity, while the foaming properties and water holding capacity were relatively poor compared to SPI. It could then be employed to soup, sauce, beverage or meat product for improving nutritional and sensory quality of these foods at appropriate pHs.     

Determination of antibacterial effects and total phenolic contents of grape (Vitis vinifera L.) seed extracts

In the study, antibacterial activities of the seed extracts of three different grapes were examined against fifteen bacteria, and total phenolic contents of the extracts were additionally determined. The contents of total phenolic compounds of the grape seed extracts were 589.09 (Hasandede), 506.60 (Emir) and 549.54 (Kalecik Karasi) mg gallic acid equivalent (GAE) per gram with acetone:water:acetic acid (90:9.5:0.5). These extracts at 1%, 2.5%, 5% and 10% concentrations were tested for their antibacterial effects by using the agar diffusion method against some pathogenic and spoilage bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, E. coli O157:H7, Klebsiella pneumoniae, Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All tested bacteria were inhibited by the grape seed extracts using agar well diffusion method. The most sensitive of the bacteria was A. hydrophila while Hasandede grape seed extract was the most inhibitive extract on test bacteria. Hasandede seed extract at 10% concentration gave the largest inhibition zone diameter (30.67 mm) against A. hydrophila. According to serial dilution method, while all the grape seed extracts at 0.5% and 1% concentrations had generally bacteriostatic activities against E. coli O157:H7, the same extracts appeared to have bactericidal effects at concentrations above 2.5%. In addition, the extracts at all concentrations had bactericidal activities against S. aureus at the end of 48 h. and A. hydrophila at the end of 1 h.     

The effects of cold storage of table grapes, sulphur dioxide and ethanol on species of black Aspergillus producing ochratoxin A

Table grapes of cv. 'Superior' were sampled from four vineyards during three seasons, for the occurrence of black Aspergillus species that can produce ochratoxin A after storage. The ochratoxin A-producing fungus, Aspergillus carbonarius , was identified in all the samples at harvest and it survived through cold storage. Storage of table grapes for 7 days at 20 °C resulted in occasional increase in the number of isolates recovered from the berries. In contrast, storage for 1 month at 0 °C, with sulphur dioxide (SO₂) generator pads reduced the number of isolates significantly or completely, depending on the dose. Dipping the clusters in ethanol prior to cold storage did not reduce the number of isolates of the Aspergillus niger aggregate after storage. Exposure of A. carbonarius to a final level of 0.4 ppm of SO₂ resulted in fewer fungal colonies than in the control, and the surviving spores developed into fungal colonies that failed to sporulate. These results demonstrate that A. carbonarius is ubiquitous on table grapes before storage and care should be taken to avoid its contamination.     

Study of agricultural by-products. Extractability and amino acid composition of grape (Vitis vinifera) skin proteins from cv palomino

Extractability in various solvents of grape skin proteins from cv Palomino, the most abundant and characteristic grape in the sherry zone, was studied. The greatest extractability was obtained in NaOH solutions. Amino acid analysis of the various protein extracts showed that the most abundant amino acid was glutamic acid and the limiting ones were tryptophan and the sulphur-containing amino acids, methionine and cystine.     

Influence of packaging film permeability and residual sulphur dioxide on the quality of pre-peeled potatoes

The effects of sodium bisulphite concentration and gas permeability of the packaging film on the surface colour, texture, exudate production and microbial growth of pre-peeled refrigerated potatoes were evaluated to determine shelf-life and the lowest level of preservative which could be used.
The product was packaged in polyethylene film, or in vacuo , using EVA-SARAN-EVA laminate and stored refrigerated. Polyethylene was not adequate in several aspects; packaging in oxygen barrier film allowed reduction of bisulphite levels, and vacuum packaging of 50 ppm bisulphite treated samples doubled the shelf-life of the product compared with aerobic packaging.     

Effects of previous storage history, hybrid, and drying method on the storability of maize grain (corn)

Maize grain (corn) from three harvest years (1986, 1991, and 1992) was harvested, dried, and stored in small bins. Samples taken at harvest and samples taken after various periods of bin storage (up to 77 months) were subjected to accelerated storage tests for measurement of carbon dioxide (CO₂) evolution. The initial (t < 72 h) slopes (SLOPE72) of CO₂ evolution rate curves were related to storability (r = 0.82), as measured by cumulative CO₂ evolution at 200 h. SLOPE72 (a faster test method than cumulative evolution) was subsequently used to evaluate the effects of the following factors on storability: (1) hybrid, (2) drying method, and (3) previous storage history. Differences in storability, attributable to hybrid, were significant both at harvest and after periods of bin storage. One extremely unusual growing year (severe drought stress) affected the otherwise consistent storability ranking among hybrids. Maize grain dried by high-temperature (95 °C) batch crossflow drying had significantly lower storability (i.e. greater SLOPE72) than did the same hybrids dried by low-temperature (ambient air) drying. Previous storage history (moisture content and duration) affected subsequent storability. Storage for longer periods, given the same moisture content, resulted in lower subsequent storability, and storage at higher moisture content, given the same time period, also resulted in lower subsequent storability.     

Morphology, anatomy and development of the pericarp after anthesis in grape, Vitis vinifera L.

Studies of the structure and cytological development of the pericarp of the grape berry are reviewed and further studies conducted using contemporary methods of histology, histochemistry, electron microscopy and traditional methods of proximate analysis to investigate post-anthesis pericarp morphology, anatomy, fine structure and tissue composition. The observations are presented within a biological and ecological context in which the pericarp, in its primary role, serves as an aid to seed dispersal, as indicated by the developmental changes it undergoes in composition and structure after anthesis. It is concluded that the pericarp embodies a broad spectrum of evolutionary responses to natural selection exerted both by biotic and abiotic factors in wild populations of grapevines. The presently used cultivars have retained these characteristics, as they have not been exposed for thousands of years, and are still not exposed, to natural selection.     

Identification of four low molecular and water‐soluble proteins from grape (Vitis vinifera L.) seeds

Profiles of soluble proteins isolated from mature seeds of grape (Vitis vinifera L.) pomace were studied using two‐dimensional polyacrylamide gel electrophoresis (2D‐PAGE) coupled with matrix‐assisted laser desorption/ionisation time‐of‐flight mass spectrometry (MALDI–TOF–MS). Two‐dimensional gels stained with Coomassie brilliant blue revealed more than fifty protein spots. Four abundant protein spots showing low molecular weight (Mr) and wide isoelectric point (pI) were analysed by MALDI–TOF–MS, resulting in their identification. Taken together, these results suggest that identified proteins may be linked to seed development and metabolism, but more instructive is that they have some potential functions for future food application. These results provide some insights into conversion of grape processing wastes into useful products or even as raw material for other industries.     

Effects of pre-bloom leaf removal on growth of berry tissues and must composition in two red Vitis vinifera L. cultivars

Background and Aims:  Little work has been conducted on the effects that summer pruning operations have on the relative growth of grapevine berry parts. Our paper studies whether pre-bloom leaf removal is able to modify the proportions of seed, skin and flesh in ripe grapevines berries and the related effects on must composition.
Methods and Results:  Pre-bloom defoliation (D) of the first six basal leaves on main shoots was applied to the field-grown cvs Barbera and Lambrusco salamino ( Vitis vinifera L.) in Italy's Po Valley and compared with non-defoliated controls. D showed reduced fruitset, hence yield per shoot, and concurrently improved must soluble solids and total anthocyanins in both cultivars as a likely result of increased leaf-to-fruit ratio (+3.4 cm²/g and +5.2 cm²/g for Barbera and Lambrusco, respectively) and improved relative skin mass (from 6.0 to 9.0% in Barbera and from 8.1 to 10.4% in Lambrusco). In both cultivars, skin and seed mass were highly correlated with total berry mass and changes in relative skin mass were generally not related to berry size.
Conclusions:  These results indicate that berry size per se is not the primary factor in determining final grape composition, which instead seems to depend upon factors differentially affecting the growth of the various berry components.
Significance of the Study:  Pre-bloom D induced a consistent, site and cultivar-independent increase in relative skin mass suggesting this effect being strongly physiologically regulated.     

High‐pressure recovery of anthocyanins from grape skin pomace (Vitis vinifera cv. Teran) at moderate temperature

The objective was to evaluate the influences of the high hydrostatic pressure extraction parameters on the recovery of anthocyanins from the grape skin pomace extracts (Vitis vinifera cv. Teran) under moderate temperatures. Studied parameters were: solvents (methanol and ethanol); solvent concentrations (30, 50, and 70%); pressures (300, 400, and 500 MPa); times (3, 6.5, 10 min); and temperatures (22, 26, 30 °C). Predominant anthocyanins in all extracts were malvidins (malvidin‐3‐glucoside as the main compound) representing 55.77% of overall anthocyanin content. The type of solvent did not significantly influence anthocyanin extraction yield, while decreased solvent concentration (increased solvent‐to‐water ratio) significantly improved extraction of anthocyanins. Increase of pressure enhanced extraction yield of the anthocyanins but temperature showed stronger impact on the anthocyanins recovery. This investigation evidenced that the best conditions for HHPE of anthocyanins from grape pomace were extraction time 3.39 min, extraction temperature 29.48 °C, pressure 268.44 MPa and solvent concentration 70%.

Practical applications

Due to increased interest for the use of cheap winery byproducts as a source of expensive polyphenols for functional food production, skins from grape pomace became valuable raw material. Therefore, there is a need to evaluate the influence of HHPE innovative extraction technology on its nutritive value during processing. Optimizing parameters for polyphenolic recovery from grape pomace is directly related with nutritional value and economics of food engineering during industrial processing. Obtained results showed that the HHPE under lower temperatures is suitable for the extraction process of anthocyanins from grape skin pomace, but more research is needed to identify other food‐grade solvents with their corresponding concentrations that are useful for the extraction assisted with high hydrostatic pressure.     

Effect of sulphur dioxide and must extraction on colour,phenolic composition and sensory quality of red table wine

Red wines were made during 1992 from Vitis vinifera var Roriz grapes using a high and a low level of extraction and three levels of total sulphur dioxide (0, 75 and 150 mg SO₂ kg⁻¹). From this single experiment, the effects of total SO₂ and extraction on anthocyanin composition and colour were observed by HPLC, spectrophotometry and tristimulus colorimetry. High extraction produced a wine with more total pigments and total phenols than low extraction and increased the amount of organic acids extracted during fermentation. More anthocyanins were extracted with increasing SO₂ levels. On maturation, all wines lost colour and increased in brownness. Wines made without SO₂ browned more than the wines made with SO₂. The anthocyanins normally present in wines were all rapidly lost to trace levels at 24 months. Vitisin A, a more stable and highly coloured anthocyanin than malvidin 3-glucoside, showed a slower decrease in concentration than malvidin 3-glucoside and contributed significantly to the wine colour during aging. At the first analysis, the wines made without SO₂ had a higher percentage colour due to polymers than the wines made with SO₂. Polymerisation progressed during maturation, although the initial differences were maintained. Sensory analysis after 6 and 18 months storage by expert tasters revealed differences mainly related to the colour attributes, indicating that when wines are made using modern hygienic techniques, total SO₂ has a negligible effect on aroma and flavour attributes. © 1998 Society of Chemical Industry.     

Antimicrobial efficacy of gaseous chlorine dioxide against Salmonella enterica Typhimurium on grape tomato (Lycopersicon esculentum)

The aim of this study was to investigate the effects of gas level and treatment condition on antimicrobial efficacy of ClO₂ gas against Salmonella enterica Typhimurium on grape tomato (Lycopersicon esculentum). Grape tomatoes were dip‐inoculated with inoculum of S. enterica Typhimurium TISTR 292 (ATCC 13311) (9.79 ± 0.39 log CFU mL^?1) and allowed to dry before treatments. The pre‐inoculated samples were exposed to 0.15–0.85 mg of ClO₂ gas, for up to 58 min. The treatments at 4 and 25 °C resulted in population reductions of S. enterica Typhimurium of up to 3.95 ± 0.22 and 7.37 ± 0.39 log CFU per fruit, respectively. The population reduction results were used to construct statistical models to predict efficacy of ClO₂ gas. The second‐order equations for treatments at 4 and 25 °C had R² of 0.87 and 0.95, respectively, and indicated that efficacy of ClO₂ gas was significantly influenced by ClO₂ gas level, exposure time and treatment temperature.     

Combining microsatellite markers and capillary gel electrophoresis with laser-induced fluorescence to identify the grape (Vitis vinifera) variety of musts

In this work, a new method that combines the use of microsatellite markers (VVMD5 and ZAG79) together with capillary gel electrophoresis with laser-induced fluorescence (CGE–LIF) is developed and applied to the identification of Albariño and Moscatel Grano Menudo musts. The GCE-LIF method uses commercially available products including polymers, DNA-intercalating dyes and bare fused silica capillaries to provide reproducible and sensitive separations of DNA fragments for grapevine characterization. The CGE–LIF procedure offers highly resolved separations of DNA fragments from 48 to 1031 bp in ca. 30 min with efficiencies up to 1.8×10⁶ plates/m allowing the separation of fragments that differ in 4 bp. The use of different DNA standards (i.e., 100 bp ladder, Ф×174 and pBR322) and their effect on size assignment of the amplified DNA is also investigated. It is demonstrated that the microsatellite markers (VVMD5 and ZAG79) provide DNA amplification patterns specific for Albariño and Moscatel Grano Menudo grapes that can be adequately differentiated by using CGE–LIF. Moreover, the DNA sizes determined by this CGE–LIF method are corroborated using a more standard procedure (i.e., an automatic genetic analyzer with a commercial kit) demonstrating the usefulness of this new methodology.     

Effect of foliar nitrogen and sulfur on petit manseng (Vitis vinifera L.) grape composition

Vineyard applications of foliar nitrogen (N) and sulfur were evaluated in the Yadkin Valley of North Carolina in 2011 and 2012 as a means to modify grape composition of Vitis vinifera cv. petit manseng. Four treatments were applied each year in a randomized complete block design with six replicates of six vines each: untreated control, soil N at 30?kg/ha, foliar N at 15?kg/ha and foliar N at 15?kg/ha plus sulfur at 5?kg/ha. Fruit ammonia and yeast assimilable nitrogen (YAN) concentrations increased in foliar-treated vines both seasons compared to control vines. Total glycosides (TGGs) increased ～80% in foliar N/sulfur-treated vines compared to control vines in 2011, and TGGs increased ～157% in foliar N/sulfur-treated vines relative to glycoside level in foliar N alone in 2012. Foliar N and foliar N/sulfur applications increased the majority of amino acid concentrations analyzed in 2011. Measured concentrations of various amino acids, partly responsible for aroma and flavor of petit manseng wines, were differentially dependent on the method of N application. Foliar applied nitrogen may be an effective technique to contribute to berry composition optimization of petit manseng grown in a warm, humid climate.     

Effect of the cluster heterogeneity on mechanical properties,chromatic indices and chemical composition of Italia table grape berries (Vitis vinifera L.) sorted by flotation

The impact of cluster heterogeneity on mechanical properties, chromatic indices and chemical composition of Italia table grape berries sorted by flotation was evaluated in this study. The density sorting at commercial harvest permitted to get berries of different ripeness and relatively different quality attributes. Individually, some grape chromatic characteristics, physical characteristics (weight of the whole berry and berry skin), content and composition of reducing sugars, organic acids and phenolic compounds (flavanols of low molecular mass in berry skins) permitted to characterise and to differentiate berries belonging to different density classes. However, the tested mechanical properties were not related to the berry density. When the variables that significantly contributed to the berry differentiation were globally assessed, the chemical parameters related to sugars (142.3–164.4 g kg^?1), content of skin oligomeric flavanols [46.3–137 mg (+)‐catechin kg^?1], berry skin weight (379–607 mg), yellow/blue colour component (26.31–29.96) and chroma (26.40–30.06) were the more representative.