Fenhexamid residues in grapes and wine

The behaviour of the fungicide, fenhexamid, on grapes, and during wine-making, as well as its effect on the microflora of alcoholic and malolactic fermentation has been studied. After treatment, the residue on grapes decreased rapidly to one-third of the initial level after the first week, while it remained constant during the following two weeks. At harvest, in the wine obtained by vinification without skins, the fungicide residue decreased on average by 49% , while in the wine obtained by vinification with skins, the decrease was on average 62% . The presence of this fungicide on grapes and in the wine did not affect alcoholic and malolactic fermentation, nor did fermentation cause any degradation of the fungicide. A simple and rapid gas chromatograhic method (GC-NPD) for the determination of fenhexamid residues in grapes, must and wine is described.     

Pesticide residues in grapes and wine in Italy

Two hundred and one pesticides comprising 84 fungicides, 88 insecticides and 29 herbicides are registered in Italy for use on grapes. Recently, the maximum residue limits (MRLs) for 16 fungicides and five insecticides were established for wine. However, literature data show that some MRLs for wine are not consistent with the corresponding values for grapes. In Italy, the Ministry of Health has the responsibility for checking pesticide contamination in fruit and vegetables in general distribution (i.e. grocery shops, food stores). From 1996 to 1999, out of 1532 grape samples analysed, levels of 1.0, 0.9, 1.8 and 1.9% in each year respectively were contaminated. As part of the National Residue Monitoring Programme, the Ministry of Agriculture carried out investigations of samples collected directly from the field (therefore of a known pesticide treatment history) in order to find the causes of the observed irregularities and to identify preventative measures. In 1996, 1998 and 1999, out of 481, 1195 and 1949 grape samples analysed, 7.9, 6.5 and 2.5% respectively were contaminated, while no residues were detected in 259 wine samples. The National Observatory on Pesticide Residues collects data from analyses performed by highly reliable, non-institutional laboratories on samples from farming cooperatives or individual farms, food companies, wholesale and retail markets. Of the 846 grapes samples and 190 wine samples collected in 1998 and 1999, a total of 6.1 and 2.1% respectively of grapes and 0% for all wine samples were found to contain residues.     

Lead contamination of raisins sold in Canada

Graphite-furnace atomic absorption spectrometric analysis of raisins imported in 1993-95 from different countries into Canada showed that raisins from Turkey had unusually high lead levels. The Turkish raisins ( n =18) contained a mean (range) of 0.93 (0.056- 3.1)mg kg -1 lead, whereas five samples from Australia, South Africa, Iran, Mexico and Chile contained a mean of 0.0085 (0.005-0.010)mg kg -1 . Acid-washing studies showed that most of the lead in the Turkish raisins was on the surface of the fruit. The impact of eating the raisins on the dietary intake of lead was estimated for Canadians of different ages and sexes. For example, eating raisins from Turkey would increase the dietary intake of lead by 1-4-year-old children from 0.97 to ~2.2 μg kg -1 body weightday -1 . The source of the lead was traced to use of a copper fungicide contaminated with high lead levels. Currently, lead levels in raisins imported from Turkey are low and approach levels in raisins from other countries. Uncontaminated raisins contain ~0.01mg lead kg -1 , and a maximum tolerance for lead in raisins of 0.1mg kg -1 is achievable irrespective of the type of raisin or country of origin. Therefore, consideration should be given to proposing this level as a maximum tolerance for lead in raisins.     

Quality control charts for storage of raisins and dried figs

 Shewhart control charts are constructed by using the Hunter Lab color scale parameters to assure maintenance of the color of raisins and dried figs during storage in modified atmosphere packages, vacuum packages, or nylon bags. These control charts may be used to maintain the quality within acceptable limits and make it possible to readjust storage conditions if the acceptable limits should be violated. Received: 11 March 1996     

Evaluation of the physical,chemical and sensory properties of raisins produced from grapes of the cultivar Crimson

The main objective of the present work was to dry grapes of Crimson variety through different methodologies in order to find an alternative for the production of raisins. Different methodologies were used for drying: solar direct exposition in a greenhouse and in convective drying chambers with constant air flow at two temperatures: 50 and 60 °C. Some chemical analyses were made, namely for total sugars, acidity, total phenols, total anthocyanins and total tannins. Also some physical properties were evaluated, specifically color and texture. A sensorial analysis of the dried products was undertaken to evaluate the acceptability by consumers. The raisins produced by the different methodologies didn’t show significant differences at the chemical and physical levels. However, it was observed that the dried samples contained higher amounts of total phenolic compounds, anthocyanins and tannins in comparison to the fresh grapes. Sensory evaluation result showed that dried grapes produced using different methodologies was similar to commercial raisins.     

Potential ochratoxin A producers from wine grapes in Argentina and Brazil

The aim was to identify the normal mycoflora in wine grapes from Argentina and Brazil. We collected 50 grapes samples from Malbec and Chardonnay varieties in each country during the 1997-98 harvest. Yeasts were a major component of the fungal population, and the most frequent genera of filamentous fungi isolated were: Aspergillus, Penicillium and Botrytis. Other genera identified (in decreasing order) were: Phythophthora, Moniliella, Alternaria and Cladosporium. From grapes, the mean frequency of filamentous fungi ranged from 1.3 × 10⁴ to 5.4 × 10⁶ CFUg^-1. We isolated 48 Aspergillus niger strains from Argentinian grape, of which eight could produce ochratoxin A. Sixteen of 53 A. niger strains from Brazilian grapes produced ochratoxin A. The results indicate that similar mycobiota were isolated from Argentinian and Brazilian wine grapes and there could be ochratoxin A production in this substrate.     

Residues of aldicarb in oranges: a unit-to-unit variability study

Residues of aldicarb and its sulphoxide and sulphone oxidative metabolites in individual Navelino orange trees were determined at several time intervals after soil application of TEMIK 10G at 200g formulated material per tree. Analysis was by HPLC with postcolumn derivatization giving average recoveries of 98% for aldicarb (RSD 6%), 34% for aldicarb sulphoxide (RSD 5%) and 77% for aldicarb sulphone (RSD 5%). Lowest calibrated levels (LCLs) were 0.02mg/ kg for aldicarb and aldicarb sulphone and 0.04mg/kg for aldicarb sulphoxide. At the recommended preharvest interval (PHI) of 120 days no detectable residues of any compound, including the parent compound, were found in any of the samples analysed. In mature fruits (PHI of 88 days) detectable residues at the LCL for aldicarb sulphoxide and 0.03 or 0.04 mg/kg for aldicarb sulphone were found in only three of the 18 samples analysed. In immature fruits detectable residues of aldicarb sulphoxide at concentrations ranging between 0.04 (LCL) and 0.51mg/kg were detected in 70 out of 88 samples analysed, while residues of aldicarb sulphone at concentrations 0.02 (LCL) to 0.8mg/kg were detected in 73 out of 88 samples. Indicative variability factors for sulphoxide and sulphone were estimated for immature fruits.     

Polyphenols and colour variability of red wines made from grapes harvested at different ripeness grade

Several red wines were elaborated in order to study the influence of the grape harvesting date (degree of maturity of the grape) on their chromatic characteristics and polyphenolic contents. Wines made from two grape varieties, at three different harvesting dates and from two consecutive vintages, were selected for this study. The results showed that the harvesting date of grapes (directly correlated with the degree of maturity of the grapes), influenced the chromatic characteristics of the wines, although their polyphenolic compositions were clearly different, especially in Cabernet Sauvignon wines. In general, higher intensities of blue or violet tones were detected in wines made from the grapes collected on the second harvesting date, in which the ratios anthocyanins/proanthocyanidins and anthocyanins/(proanthocyanidins + catechins) were the lowest. These ratios are proposed as probable indicators of the aptitude for wine ageing.     

Study of polyamines and their precursor amino acids in Grenache noir and Syrah grapes and wine of the Rhone Valley

Polyamines and their amino acid precursors were determined in Grenache and Syrah grapes and in wines made from these grapes. The compounds analysed were the polyamines putrescine, spermidine, and spermine, in addition to their precursors, ornithine, agmatine and arginine. The analytes were determined by reversed-phase high performance liquid chromatography (HPLC) with fluorescence detection using FMOC (fluorenylmethylchloroformate) as a pre-column derivatising agent Grape clusters were sampled from flowering to full maturity at different developmental stages. In addition, different berry parts were analysed separately from half veraison onwards. It appears that at berryset there is a decrease in the concentration of arginine, whereas polyamine concentrations remain constant at this stage. Concentrations of polyamines increased from must to alcoholic to malolactic fermentation; putrescine was the most abundant in wine (mean concentration after malolactic fermentation, MLF was 4.93 mg/l) followed by spermidine and then spermine (mean concentrations after MLF were 1.84 and 0.17 mg/l, respectively). In three of the four fermentation sites concentrations of all three compounds were greater in Syrah than in Grenache wines. In both varieties, it appears that polyamine biosynthesis occurs preferentially from arginine via agmatine. In all cases, concentrations of polyamines found in these grapes and wines were significantly below the levels typically found in other fermented foods.     

Phenolic compounds and fatty acids in different parts of Vitis labrusca and V. vinifera grapes

trans-Resveratrol, antioxidant activity, phenolic compounds, proximate composition, and fatty-acid composition were quantified in different parts (peel, pulp, and seeds) of four grape varieties: Brazil (Vitis vinifera), Benitaka (V. vinifera), Isabel (Vitis labrusca) and Niagara (V. labrusca). Large concentrations of polyunsaturated fatty acid (18.84 and 9204.27 mg 100 g^− 1), linoleic acid (LA, 18:2n-6), from 5890.87 to 9148.93 mg 100 g^− 1, and alpha-linolenic (LNA, 18:3n-3), from 5.25 to 56.85 mg 100 g^− 1, were found in different parts of the four grape varieties. The lowest concentrations necessary for 50% inhibition of DPPH were (9.26 to 126.91 ??g mL^− 1) in seeds; the pulp did not have antioxidant activity. The total phenolic content varied between 0.04 and 122.35 mg EAG g^− 1; seeds had the highest concentrations (89.83 to 122.35 mg EAG g^− 1), especially in Niagara and Isabel varieties. trans-Resveratrol was detected in peels (1.17 to 12.96 ??g g^− 1) and seeds (2.03 to 2.44 ??g g^− 1) of the four varieties; however, it was absent in the pulp.     

Antioxidant activity and phenolic content of 16 raisin grape (Vitis vinifera L.) cultivars and selections

Six raisin grape cultivars and 10 new raisin grape selections were analyzed for antioxidant activity (ABTS assay) and for total and individual phenolic compounds. Samples were freeze–dried and values are reported on a dry weight basis. Antioxidant activity across the 16 samples ranged from 7.7 to 60.9 μmol Trolox/g DW, with A95-27 exhibiting the greatest activity. Total phenolic content, determined in gallic acid equivalents using the Folin–Ciocalteau assay, ranged from 316.3 to 1141.3 mg gallic acid/100 g DW and was strongly correlated (r = 0.990) with antioxidant results. Concentrations of individual phenolics were determined by HPLC. trans-Caftaric acid was the predominant compound in all samples. A95-15 contained the lowest concentration (153.5 μg/g DW) of caftaric acid, while Fiesta contained the highest concentration (598.7 μg/g DW). Selections A56-66, A95-15, and A95-27 had much higher levels of catechin (86.5–209.1 μg/g DW) and epicatechin (126.5–365.7 μg/g DW) than the other samples.     

Phenolic content and antioxidant capacity of Chinese raisins produced in Xinjiang Province

Raisins of 9 grape genotypes from Xinjiang Province were evaluated for phenolic composition and dietary antioxidant potential by using several assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity, cupric reducing antioxidant power (CUPRAC), nitrite scavenging capacity (NTSC), potassium ferricyanide reducing power (PFRAP), and hydroxyl radical scavenging capacity (HRSC). Desert king had the highest content of total phenolics, total flavonoids, oligo proanthocyanidin, and total flavanols. Significance analysis demonstrated that Desert king had the highest antioxidant capacity in DPPH, CUPRAC, NTSC, and PFRAP. In HRSC, red manaizi showed the highest antioxidant capacity. 3,4-Dihydroxybenzoic acid was the predominant phenolic compound in the majority of raisin samples.     

食品中氨基甲酸酯类农药残留的检测方法研究进展

目前氨基甲酸酯类农药被广泛应用,其母体及代谢产物有较为严重的毒害作用。建立快速、灵敏、有效的氨基甲酸酯类农药残留的检测技术,成为当前研究者关注的课题。本文综述了近年来食品中氨基甲酸酯类农药残留分析的前处理及其检测技术,并对氨基甲酸酯类农药残留检测的发展前景进行了展望。     

Rapid Method for Determination of Phosphine Residues in Wheat

A rapid method for spectrophotometric determination of phosphine residues in wheat has been developed. Phosphine-fumigated wheat kernels were added with 10% sulfuric acid in a gas-tight flask, and phosphine was released into the headspace by microwave irradiation. Phosphine was spectrophotometrically determined after reaction with silver nitrate. A good linearity of the calibration curve was obtained with wheat spiked at levels ranging from 0.035 to 0.230 μg/g with correlation coefficient (r) of 0.9965 and a detection limit of 0.026 μg/g. The total time of analysis was 10 min. Headspace analysis was also performed by micro-gas chromatography (GC) with a thermal conductivity detector (micro-GC-TCD). Results obtained with the spectrophotometric and micro-GC-TCD methods showed good correlations with those obtained with the most widely used GC with nitrogen–phosphorus detector with r values of 0.9940 and 0.9946, respectively.     

Changes in 4-hexylresorcinol residues during processing of deepwater pink shrimp (Parapenaeus longirostris)

Hexylresorcinol has been used as an alternative to sulphites for prevention of melanosis or black-spot of the shrimp carapace. In order to estimate consumption of 4-hexylresorcinol, residual levels have been evaluated in deepwater pink shrimp (Parapenaeus longirostris) following dip treatments and different processing technologies (freezing, cooking and washing). The effect of 4-hexylresorcinol on the microbial growth in the dipped shrimp as well as change in the inhibitory solution during repeated utilization was also followed. The use of 4-hexylresorcinol at concentrations of 0.10 or 0.25 mg/kg led to the detection in pink shrimp of residue levels considerably higher than the limit level of 2 mg/kg. Furthermore, the processing technologies studied also showed a very low efficiency in the reduction of residues from the initial loads to acceptable values. Though the tested initial bacterial load of the shrimp was higher than it is normally expected onboard the solution of 4-hexylresorcinol did not evidence any tendency for an increase of the bacterial counts even after 29 h of utilization. No decrease in the 4-hexylresorcinol concentration is visible even after 8 dips and 29 h of solution use.     

Phylogenetic characterization and ochratoxin A--fumonisin profile of black Aspergillus isolated from grapes in Argentina

Aspergillus section Nigri populations isolated from seven growing regions from Argentina were characterized by sequencing in order to identify species responsible for production of ochratoxin A (OTA) and fumonisins (FB_s). Sequences of genes encoding calmodulin, β-tubulin, the second largest subunit of RNA polymerase II and translation elongation factor 1 alpha were analysed. The phylogenetic analysis showed the presence of six lineages: A. carbonarius, A. tubingensis, A. niger, A. japonicus, A. homomorphus and A. foetidus grouped in four major clusters. The molecular tools used allowed the identification for the first time of A. homomorphus from vineyards. OTA production confirmed the importance of A. carbonarius as the main ochratoxigenic species isolated and, to a variable degree, of A. niger and A. tubingensis, which were by far the most commonly occurring species on grapes in Argentina. The only strains able to produce OTA and fumonisins (B₂-B₄) belong to the A. niger cluster.     

Residues of the fungicide famoxadone in grapes and its fate during wine production

Famoxadone is a recently applied fungicide to vines that belongs to the oxazolidinedione family. The fate of famoxadone was studied by considering the decay ratio of this fungicide during the maturation of grapes and wine production. The main factors affecting the presence of fungicide residues such as fruit growth, photodegradation, evaporation, thermodegradation and co-distillation were studied with model systems. An experimental field was treated with a commercial product containing famoxadone at the recommended dose. After this application, residues of famoxadone were found in grapes at 0.27 ± 0.06 mg kg^-1. In this field experiment, the half-life (t_1/2;) of famoxadone, which is described by pseudo-first-order kinetics (R² = 0.74), was 18 ± 6 days, resulting from the photodegradation. The famoxadone residue levels in grapes were below the established maximum residues level for Europe (2 mg kg^-1), whilst levels in wine, carried out with and without maceration, were below the calculated limit of detection of the method.     

First steps towards the development of a non-destructive technique for the quality control of wine grapes during on-vine ripening and on arrival at the winery

NIR spectroscopy was used as a non-destructive technique for the assessment of changes in certain internal quality properties of wine grapes (Vitis vinifera L.) during on-vine ripening and at harvest. A total of 108 different wine grape samples were used to construct calibration models based on reference data and NIR spectral data, obtained using a commercially-available diode-array spectrophotometer (380-1700 nm). The feasibility of testing bunches of intact grapes was investigated and compared with more traditional methods of presentation, such as berries or must. Predictive models were constructed to quantify changes in soluble solid content (SSC, °Brix), reducing-sugar content (g/l), pH-value, titrable acidity (g/l tartaric acid), tartaric acid (g/l) and malic acid (g/l), these being the major parameters used to chart ripening. NIRS technology provided good precision for the bunch analysis mode assayed for SSC (r² = 0.89; SECV = 1.41 °Brix), for reducing-sugar content (r² = 0.87; SECV = 17.13 g/l) and for pH-value (r² = 0.69; SECV = 0.19). Models developed for testing other fruit acidity parameters yielded results sufficient to provide a screening tool to distinguish between low and high acidity values in intact grapes. Significantly, the results obtained with bunch presentation were similar to those obtained with berries and must, thus justifying further implementation of NIRS technology for the non-destructive analysis of quality properties both during on-vine ripening and on arrival at the winery. This method allows musts to be processed separately depending on initial grape quality, assessed with a single spectrum measurement and in a matter of seconds.     

Development of a green fluorescent tagged strain of Aspergillus carbonarius to monitor fungal colonization in grapes

An enhanced green fluorescent protein has been used to tag an OTA-producing strain of Aspergillus carbonarius (W04-40) isolated from naturally infected grape berries. Transformation of the fungus was mediated by Agrobacterium tumefaciens. The most efficient transformation occurred when the co-cultivation was done with 10⁴ conidia due to higher frequency of resistance colonies (894 per 10⁴ conidia) and lower background obtained. To confirm the presence of the hph gene in hygromycin resistant colonies, 20 putative transformants were screened by PCR analysis. The hph gene was identified in all the transformants. Variation on the expression levels of the eGFP was detected among the transformants and 50% of them appeared bright green fluorescent under the microscope. Microscopic analysis of all the bright fluorescent transformants revealed homogeneity of the fluorescent signal, which was clearly visible in the hyphae as well as in the conidia. eGFP expression in A. carbonarius was shown to be stable in all transformants. Confocal Laser scanning microscopy images of grape berries infected with the eGFP transformant demonstrated fungal penetration into the berry tissues. OTA production was importantly increased in the eGFP transformant in comparison with the wild type strain and pathogenicity on grape berries was slightly decreased after four days of inoculation. However, no differences in virulence were found after seven days of inoculation, thus allowing utilization of this eGFP mutant for in situ analysis of A. carbonarius infection of grape berries. To our knowledge, this is the first report describing the construction of a GFP-tagged strain belonging to Aspergillus section Nigri for monitoring Aspergillus rot on grape berries.     

In vitro binding of bile acids by bananas,peaches, pineapple,grapes, pears,apricots and nectarines

The in vitro binding of bile acids by bananas (Musa × paradisiaca), peaches (Prunus persica), pineapple (Ananus comosus), grapes (Vitis spp.), pears (Pyrus communis), apricots (Prunus armeniaca) and nectarines (Prunus persica, nectarina) was determined using a mixture of bile acids secreted in human bile at a duodenal physiological pH of 6.3. Six treatments and two blank incubations were conducted, testing various fresh fruits on an equal dry matter basis. Considering cholestyramine (bile acid binding, cholesterol lowering drug) as 100% bound, the relative in vitro bile acid binding percentages on dry matter (DM), total dietary fibre and total polysaccharides basis were 2–9%, 15–101% and 10–101%, respectively. Bile acid binding, on a DM basis, for bananas was significantly (P ? 0.05) higher and that for nectarines significantly lower than those for peaches, pineapple, grapes, pears and apricots. The bile acid bindings for peaches and pineapple were similar and significantly higher than those for grapes, pears and apricots. Binding values for grapes and pears were significantly higher than apricots. These results point to the relative health promoting potential of bananas > peaches = pineapple > grapes = pears > apricots > nectarines, as indicated by their bile acid binding on a DM basis. The variability in bile acid binding between the fruits tested maybe related to their phytonutrients, antioxidants, polyphenols, flavonoids (anthocyanins, flavonols, and proanthocyanidins), structure, hydrophobicity of undigested fractions, anionic or cationic nature of the metabolites produced during digestion or their interaction with active binding sites. Animal studies are planned to validate in vitro bile acid binding of fruits, observed herein, to their healthful potential, atherosclerosis amelioration and cancer prevention.