The relationship between the expression of abscisic acid biosynthesis genes, accumulation of abscisic acid and the promotion of Vitis vinifera L. berry ripening by abscisic acid

Background and Aims:  Grapevines ( Vitis vinifera L.) are considered to have non-climacteric fruit, but the trigger initiating ripening (veraison) is poorly understood. This study aimed to further investigate the role of abscisic acid (ABA) during berry ripening.
Methods and Results:  In field-grown grapes over three seasons, free ABA levels increased at veraison then subsequently declined to low levels. Bound ABA increased as the free ABA level decreased after 10–11 weeks post-flowering (wpf), but ABA must also be degraded and/or exported. The absence of a large pool of bound ABA before veraison makes it unlikely that the increase in free ABA is due to the mobilization of conjugated ABA. The expression pattern of genes crucial for ABA synthesis, zeaxanthin epoxidase and two 9-cis-epoxycartenoid dioxygenases (NCEDs) indicates that berries may have the potential to synthesize ABA in situ . However, the expression profile of these genes did not correlate well with ABA levels indicating that ABA accumulation is under more complex control. The application of (+)-ABA advanced ripening as measured by colour formation, berry size increase and to a lesser extent sugar accumulation and altered the expression of one of the NCED genes.
Conclusions:  The changes in berry ABA levels around the time of veraison, which influence the timing of ripening, are under complex developmental control.
Significance of the Study:  The improved understanding of the control of berry ripening is vital to attempts to successfully manipulate this process.     

Phenological sensitivity of berry growth and composition of Tempranillo grapevines (Vitis vinifera L.) to water stress

Background and Aims:  The effect of water stress on berry quality is not fully understood. This study was designed to analyse the differential phenological sensitivity of Tempranillo berry quality to water stress during three phenological stages.
Methods and Results:  Two-year-old potted Tempranillo vines were exposed to four levels of irrigation (100, 50, 25, and 0% of evapotranspiration) during three phenological stages (Stage I, from anthesis to fruitset; Stage II, pre-veraison; Stage III, post-veraison). Vine water status was monitored by means of leaf water potential measurements. Berry quality was measured at harvest and defined by the following parameters: berry dry weight, soluble solids content, titratable acidity, polyphenol and anthocyanin concentrations in the must. Berry dry-matter accumulation was more sensitive to water stress applied during Stage I and Stage II than in Stage III. Berry quality tended to decrease linearly with increasing water stress during Stage II. During Stage III, berry quality increased linearly for light-to-mild levels of water stress, whereas quality decreased above a certain water-stress threshold (Ψ_leaf = −1.12 MPa).
Conclusions:  Tempranillo berry quality demonstrated great phenological sensitivity to water stress. Pre-veraison water stress negatively affected berry quality in Tempranillo vines, whereas post-veraison water stress increased quality up to a certain threshold of Ψ_leaf.
Significance of the Study:  For the first time, this research reports a plant-based water status threshold in Tempranillo vines above which post-veraison water stress can negatively affect berry quality.     

Biochemical comparison of two grape varieties differing in juice acidity

The winegrape cv. Cabernet Sauvignon and the tablegrape cv. Gora Chirine (both Vitis vinifera L.) differ in the acidity of their berry juice. The changes in pH, titratable acidity and the concentration of compounds of the berry juice were measured from 20–30 d before veraison to harvest on plants cultivated in the glasshouse. The difference in acidity between the juice of the two varieties appeared before veraison. At harvest, the berry juice of Gora Chirine had a pH of 5.2 and titratable acidity (TA) of 32 meq/L while that of Cabernet Sauvignon had a pH of 3.2 and TA of 150 meq/L. To evaluate cellular compartmentation in the berry pericarp, vacuolar pH was measured on intact berries at two growth stages, using ¹³C nuclear magnetic resonance (NMR). Vacuolar pH did not differ significantly between the two cvs. The lower TA of Gora Chirine juice could be attributed to lower concentrations of all three major acids, malic, tartaric and citric, and to a higher concentration of potassium. At veraison, the malic acid concentration in the berry juice of Cabernet Sauvignon was about seven times higher than that of Gora Chirine. The accumulation of hexoses, especially glucose, occurred earlier during the berry growth cycle in Gora Chirine than in Cabernet Sauvignon. The osmotic potential of the Gora Chirine juice, before veraison, was lower than could have been expected because of low acidity. This was due to the compensatory effect of early accumulation of glucose. Amino acid concentration was significantly higher in Gora Chirine than in Cabernet Sauvignon, especially just before veraison. The role of organic acids in berry acidity and osmotic potential, and various metabolic processes that may lead to the difference in organic acid concentration, are discussed.     

Determination of flavonoids and ascorbic acid in grapefruit peel and juice by capillary electrophoresis with electrochemical detection

Grapefruit (Citrus paradisi Mact. (Rutaceae)) has been known for its accumulation of flavonoids and ascorbic acid. These contents are important because of their nutritional and antioxidant properties. Five flavonoids (hesperidin, naringin, hesperedin, narigenin and rutin) and ascorbic acid were separated and determined in grapefruit juice by capillary electrophoresis with electrochemistry detection (CE-ED). Two flavonoids (hesperidin, naringin) and ascorbic acid were found in extract of grapefruit peel with the same method. And the distribution comparision of the ingredients between juice and peel was discussed. The effects of several CE parameters on the resolution were studied systematically. Under the optimum conditions, the analytes could be well separated within 25 min in a 60 mmol L⁻¹ borate buffer (pH 9.0). The response was linear over four orders of magnitude with detection limits (S/N = 3) ranging from 1.4 × 10⁻⁷ to 1.0 × 10⁻⁶ g ml⁻¹ for the analytes. The method has been successfully applied for the analysis of grapefruit with satisfactory results.     

Effect of Organic Acids and Plant Extracts on Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella Typhimurium in Broth Culture Model and Chicken Meat Systems

ABSTRACT:  Foodborne illness due to consumption of products contaminated with  Salmonella  Typhimurium ( S .T.),  Listeria monocytogenes  ( L.m. ), and  Escherichia coli  O157:H7 ( E.c. ) results in many deaths and significant economic losses each year. In this study, acetic (AA), citric acid (CA), lactic acid (LA), malic acid (MA), and tartaric acid (TA) and grape seed (GS), green tea (GT), bitter melon seed (BMS), rasum, and fenugreek (FG) extracts were investigated as inhibitors against  S .T.,  L.m.,  and  E.c . in both broth-culture and meat systems. Brain Heart Infusion solutions containing 18.7, 37.5, and 75.0 mM organic acids and 5, 10, 20, and 40 mg/mL extracts were challenged with approximately log 6 CFU/mL  S .T.,  L.m ., and  E.c . A pH-adjusted control was included to determine pH effect on exhibited antibacterial activity. For the meat system, 1 to 2 g chicken breast pieces were vacuum-infused with CA/MA/TA acid at 75 and 150 mM and GS and GT at 3000, 6000, and 9000 ppm in a partial factorial arrangement. GT and GS showed considerable activity in broth-culture. All organic acids were effective in broth-culture at 75 mM after 24 h ( P  < 0.05). CA and TA were effective at 37.5 mM. CA/MA/TA at 150.0 mM were the most effective in the meat system, reducing  E.c. ,  L.m.  and  S. T. by >5, >2, and 4-6 log CFU/g, respectively, although all organic acids showed some antibacterial activity at 75.0 and 150.0 mM. These findings demonstrate the effectiveness of organic acids and plant extracts in the control of  S .T.,  L.m ., and  E.c.  O157:H7.     

Comparison of enzymes involved in sugar metabolism from Shang-24 (Vinifera quinguangularis) and Cabernet Sauvignon (Vinifera vinifera) at veraison

Background and Aims:  Sugar is a main contributor to the quality of grape berries, but little is known about the characteristics of sugar metabolism in Chinese wild grapes. Here, enzymes related to sugar metabolism were investigated in berries of both Shang-24 ( Vitis quinguangularis Rehd), a wild grape native to China, and Cabernet Sauvignon ( V. vinifera L.).
Methods and Results:  Analyses using high performance liquid chromatography and spectrophotometer showed that Shang-24 contained lower levels of glucose and fructose, compared with Cabernet Sauvignon, but had higher activities of enzymes related to sugar hydrolysis, particularly soluble acid invertase (SAI) and β-amylase. Analyses of enzyme kinetics, enzyme-linked immunosorbent assay and Western blot revealed that SAI and β-amylase in Shang-24 had low K_m values and that high levels of both enzymes were present. Furthermore, a novel peptide of SAI of 105 kDa was detected in Shang-24 along with a peptide of 60 kDa that also was present in Cabernet Sauvignon.
Conclusions:  It is thus suggested that biochemical characteristics of SAI and β-amylase in Shang-24 differ from those in Cabernet Sauvignon, and the novel peptide may be related to high activity of SAI in Shang-24.
Significance of the Study:  These data provide an essential basis for further study of the genetic regulation of sugar and its metabolism in grape berries.     

Variation in Shiraz berry size originates before fruitset but harvest is a point of resynchronisation for berry development after flowering

Background and Aims:  Asynchronous berry development results in variation in berry size and berry composition. Variation in berry size affects vineyard yield, wine quantity and berry composition, while variation in berry composition affects fruit flavour and wine quality. The objective of this study is to identify when variation in berry size begins.
Methods and Results:  Shiraz bunches were sampled at seven stages throughout the growing season and the development of individual berries was characterised by measurements of weight, volume, surface area, deformability, seed number and seed weight. Coefficients of variation with respect to berry weight, volume and surface area were elevated throughout the post-flowering period but declined as the berries approached harvest ripeness.
Conclusions:  Variation in berry size originates prior to berry set, most probably during differentiation in the floral primordium at budburst. Harvest represents a point of resynchronisation in berry development when a number of physiological changes become synchronised between berries and within the bunch.
Significance of the Study:  Variation in berry size is presumed by the wine industry to have a negative impact on crop level, fruit composition and wine quality. Much of this presumption is scientifically unsubstantiated. The findings of this paper should encourage grapegrowers and winemakers to modify the timing of the harvest to coincide with a reduction in variation in berry size.     

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.     

Effects of novel hybrid and traditional rootstocks on vigour and yield components of Shiraz grapevines

Background and Aims:  The influence of grapevine rootstocks on vine vigour and crop yield is recognized as an integral part of viticultural management. However, the genetic potential of Vitis species rootstock hybrids for vigour and yield control is not fully exploited in Australian viticulture. The effect of 55 novel inter- and intra-species hybrids and five traditional hybrid rootstock cultivars on winter pruning weight, berry size and fruit yield of grafted Shiraz vines is presented. The genetic predictions that resulted from this analysis were used to illustrate how rootstocks that best perform for a combination of traits may be selected.
Methods and Results:  The use of linear mixed models and residual maximum likelihood procedures took into account repeated measures and spatial variation within a large field trial (720 vines). Over 6 years of assessment, variation of up to 93.9% in winter pruning weight, 81.9% in fruit yield and 21.0% in berry weight between rootstocks was estimated.
Conclusions:  The effect of rootstock genotype accounted for marked differences in conferred pruning weight, berry weight and fruit yield from trial averages. Comparison of statistical analysis techniques illustrated that the choice of such techniques may influence the outcome of genetic selection from field trial data.
Significance of the Study:  Such quantification of the variation between vines in vigour, fruit yield and berry size due to rootstock genotype provides a framework for selection of well-performing genotypes for inclusion in advanced generations of the CSIRO vine rootstock breeding program.     

Role of peroxyacetic acid, octanoic acid, malic acid, and potassium lactate on the microbiological and instrumental color characteristics of ground beef

Abstract: This study evaluated the effects of peroxyacetic acid (PAA), malic acid (MA), octanoic acid (OA), and potassium lactate (KL) followed by mixing with trisodium phosphate (TSP) and an ultra‐chilled CO₂ snow shower on microbial counts of Escherichia coli (EC), coliform (CF), aerobic plate count (APC), and Salmonella Typhimurium (ST) on inoculated beef trimmings and the instrumental color attributes of the resultant ground beef. Beef trimmings inoculated with EC and ST were treated with either 0.02% PAA; 2% MA; 0.04% OA; or 2% KL, followed by mixing with 10% TSP and rapid chilling with CO₂ snow shower. Treated trimmings were then ground, packaged, displayed under simulated retail conditions, and sampled on days 1, 2, 3, 5, and 7 for microbial counts and instrumental color characteristics. PAA, MA, OA, and KL reduced (P < 0.05) the microbial counts of EC, CF, APC, and ST during display. Among treatments, OA was most effective on EC, CF, ST, and APC during retail display. Chilling beef trimmings with CO₂ improved instrumental color characteristics of the produced ground beef but made little difference in reducing microbial counts during display. During retail display, ground beef produced from beef trimmings treated with antimicrobials tended to maintain redness, myoglobin redox form stability (630 nm/580 nm), and overall instrumental color characteristics. Practical Application: This research provides a practical and cost‐effective decontamination technology for beef processors that can be immediately implemented in the ground beef production chain. Using antimicrobial intervention coupled with rapid chilling could benefit the meat industry by preserving the quality attributes of ground beef during retail display under aerobic packaging environment.     

Effects of mechanical handling,storage on ice and ascorbic acid treatment on lipid oxidation in cultured Newfoundland blue mussel (Mytilus edulis)

Lipid oxidation of cultured blue mussels (Mytilus edulis) during mechanical handling and storage on ice was investigated. Furthermore, the exposure of blue mussels to ascorbic acid (Asc) as an antioxidant and its effects on lipid oxidation of sample was monitored. Thiobarbituric acid reactive substances (TBARS) of stored mussels were significantly (p < 0.05) higher than those of the fresh mussels. Mechanical handling of mussels, which includes washing, sorting and packaging, for up to 1 h did not affect their oxidative status significantly (p < 0.05). Furthermore, exposing live mussels to specific concentrations of Asc retarded lipid oxidation significantly (p < 0.05) during storage on ice for only 5 days, after which the Asc became a pro-oxidant.     

The influence of seed weight on the development and growth of berries and live green ovaries in Vitis vinifera L. cvs. Pinot Noir and Cabernet Sauvignon

Background and Aims:  Variation in berry size is observed at harvest. Although the growth of seeded berries has been described, no such data are reported for seedless berries or live green ovaries that occur in wine cultivars. This study describes the growth of individual berries in relation to seed development.
Methods and Results:  Regular measurements of berry diameter described the growth of Pinot Noir and Cabernet Sauvignon. Seeded berries had typical double sigmoid growth curves, whereas seedless berries, which developed more slowly from midway through Phase I, continued to grow in Phase III if a seed trace was present. Berries without a seed trace did not enlarge after Phase II. Live green ovaries failed to grow after a small initial expansion post-cap fall.
Conclusion:  Seeded berries had double sigmoid growth as a result of cell division and expansion, whereas the growth of seedless berries and live green ovaries was the result of cell expansion alone. Seed development is necessary for cell division within the mesocarp.
Significance of the Study:  Seed development is essential for the full development of Pinot Noir and Cabernet Sauvignon berries. The data suggest that divergence of berry development from a characteristic growth curve may be linked to the extent of seed development.     

Classification of reproductive performance of ten winegrape varieties

Background and Aims:  Flowering and fruitset are principal determinants of grapevine yield. Poor fruitset is said to limit the yield of many varieties in most regions in Australia; however, there is a lack of knowledge of the reproductive performance of most varieties under Australian conditions.
Methods and Results:  The reproductive performance of Vitis vinifera winegrape varieties – Cabernet Sauvignon, Chardonnay, Merlot, Nebbiolo, Pinot Noir, Sangiovese, Sauvignon Blanc, Shiraz, Tempranillo, and Zinfandel – was studied in four consecutive growing seasons (commencing in 2004/05) across a range of climatic regions from cool (Adelaide Hills) to warm (Adelaide Plains). Measures of reproductive performance included flower number per inflorescence, fruitset (%), berry number per bunch, coulure index (CI), and millerandage index (MI). Principal component analysis and agglomerative hierarchical classification were used to group the varieties into three classes of reproductive performance.
Conclusions:  Certain varieties have a reputation of having 'poor fruitset' that has been inferred from relatively low berry number per bunch; however, for some of these varieties, it is 'low flower number per inflorescence' rather than 'poor fruitset' that is the cause of low berry number.
Significance of the Study:  An improved understanding of the reproductive performance of winegrape varieties has been achieved.     

Determination of ascorbic and isoascorbic acid in beverages and additives to meat products by capillary isotachophoresis

 A isotachophoretic method with conductivity detection was developed to directly determine ascorbic acid in food samples. The leading electrolyte contained hydrochloric acid (10 mmol/l), β-alanine (pH 3.0), and methylhydroxyethylcellulose (0.1%). The terminating electrolyte was 5 mmol/l caproic acid. The method is suitable for determining ascorbic acid in juice, beers, and as additives to meat products. The method was also applied for the determination of isoascorbic acid in additives to meat products. Received: 21 February 2000 / Revised version: 15 May 2000     

Involvement of abscisic acid and polyamines in berry ripening of Vitis vinifera (L.) subjected to water deficit irrigation

Background and Aims: Partial rootzone drying (PRD) is an irrigation system that permits better control of vegetative growth without reducing fruit yield. However, little is known about how grapevine reproductive development is regulated when irrigated under PRD. Therefore, the aim of this work was to investigate the relationship between abscisic acid (ABA) and polyamines (PAs) in leaves and berries during ripening, and how hormonal balance is affected under different irrigation regimes.
Methods and Results: The study was carried out using container-grown Superior Seedless grapevines with a split-root system and grown under controlled conditions in a greenhouse. Three irrigation treatments were imposed: control (well watered), and two forms of deficit irrigation – PRD and sustained deficit irrigation (SDI). PRD plants have higher yield and berry size than SDI vines. At the onset of veraison, PRD berries have higher ABA, free PAs and free to bound PA ratio than other treatments.
Conclusions: Although the restriction of vegetative growth in PRD might be partly a response to the volume of water applied and therefore similar to a SDI response, our results suggest that specific hormonal factors may explain the effects on reproductive growth and yield.
Significance of the Study: The study demonstrates that changes induced in berry ABA during PRD conditions could be counterbalanced by changes in PA metabolism so that berry size and yield are maintained.     

Effects of ascorbic acid, sodium metabisulfite and sodium chloride on freshness retention and microbial growth during the storage of Manzanilla-Aloreña cracked table olives

The effect of the mixture of sodium metabisulfite (SM), ascorbic acid (AA), and NaCl on the surface colour of fruits and microbial growth during the storage of cracked Manzanilla-Aloreña table olives was studied. During storage, the green colour of fruits, measured by the hue angle (tang⁻¹(b/a)), decreased rapidly, indicating a degradation in the green and a change towards more reddish tones. The degreening rate (k_c) was lower for the highest AA concentration, while the highest final hue angle was found for the highest SM level, indicating different antioxidant mechanisms. Enterobacteriaceae were not enumerated after 20 days of brining. AA, SM, and NaCl, within the concentrations essayed, did not affect yeast growth; however, lactic acid bacteria (LAB) were partially inhibited by the presence of SM and AA, showing the highest growth rate in the absence of both. The maximum population of LAB was reached at levels of SM below 0.75 g/l, intermediate AA (7.5 g/l) and NaCl (70 g/l) concentrations. Appropriate storage conditions could be obtained at the maximum levels of AA (15.0 g/l) and SM (1.5 g/l) and the lowest level of NaCl (60 g/l).     

Comparative study of 11 phenolic acids and five flavan-3-ols in cv. Vidal: impact of natural icewine making versus concentration technology

Background and Aims:  In an effort to protect the development of the icewine production industry, this study aimed to find indicators to distinguish between authentic and non-authentic icewines.
Methods and Results:  Fully ripened berries were used to prepare three types of high-sugar grape juices: naturally frozen juice, refrigerator-frozen juice and concentrated juice. The content of phenolic acids and flavan-3-ols in the samples before and after fermentation was assayed. Significant differences were found in the individual level of most phenolic acids and flavan-3-ols except chlorogenic acid, sinapic acid and (−)-epicatechin among the three types of high-sugar juices. At the end of fermentation, there were significant differences in the wines, not attributable to the influence of yeasts.
Conclusions:  Vanillic acid, caffeic acid, (−)-epigallocatechin gallate, gentisic acid and syringic acid may be used as indicators of authentic icewine.
Significance of the Study:  This work provides a basis for distinguishing authentic icewine and controlling icewine quality.     

Pomological features, nutritional quality, polyphenol content analysis, and antioxidant properties of domesticated and 3 wild ecotype forms of raspberries (Rubus idaeus L.)

Abstract: The raspberry (Rubus idaeus L.) is an economically important berry crop that contains many phenolic compounds with potential health benefits. In this study, important pomological features, including nutrient content and antioxidant properties, of a domesticated and 3 wild (Yayla, Yavuzlar, and Yedigöl) raspberry fruits were evaluated. Also, the amount of total phenolics and flavonoids in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were calculated as gallic acid equivalents (GAEs) and quercetin equivalents (QE). The highest phenolic compounds were found in wild Yayla ecotype (26.66 ± 3.26 GAE/mg extract). Whilst, the highest flavonoids were determined in wild Yedigöl ecotype (6.09 ± 1.21 QA/mg extract). The antioxidant activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were investigated as trolox equivalents using different in vitro assays including DPPH^?, ABTS^?+, DMPD^?+, and O^??₂ radical scavenging activities, H₂O₂ scavenging activity, ferric (Fe³⁺) and cupric ions (Cu²⁺) reducing abilities, ferrous ions (Fe²⁺) chelating activity. In addition, quantitative amounts of caffeic acid, ferulic acid, syringic acid, ellagic acid, quercetin, α‐tocopherol, pyrogallol, p‐hydroxybenzoic acid, vanillin, p‐coumaric acid, gallic acid, and ascorbic acid in lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits were detected by high‐performance liquid chromatography and tandem mass spectrometry (LC‐MS‐MS). The results clearly show that p‐coumaric acid is the main phenolic acid responsible for the antioxidant and radical scavenging activity of lyophilized aqueous extracts of domesticated and wild ecotypes of raspberry fruits.     

Determination of ascorbic acid in vegetables and fruits by differential pulse polarography

A method for the determination of ascorbic acid in vegetables and fruits using differential pulse polarography has been developed. The extraction medium recommended is a mixture of oxalic acid (1%), trichloroacetic acid (2%) and sodium sulphate (1%), and simple filtration is used to remove the residue. An acetate buffer (2M) is recommended to keep the pH at 4.5. The polarograms were recorded using a modulation amplitude of 50mV, a scan rate of 2mVs^?1, and a drop time of 1 s. The precision of the procedure was found to be 1.4% at the 1 mg litre^?1 level of ascorbic acid. The calibration graph was linear in the range of 0–20 mg litre ^?1 of ascorbic acid with a slope of 0.48μA mg litre^?1. Most common anions and cations did not interfere, however, Fe³⁺ and EDTA interfered, and Br^? and I^? seriously interfered with the determination. The method was applied to determine the ascorbic acid content of a number of vegetables and fruits using the standard-addition calibration.