Enriched ozone atmosphere enhances bioactive phenolics in seedless table grapes after prolonged shelf life

‘Autumn Seedless’ table grapes (Vitis vinifera L.) were stored for up to 60 days at 0 °C under ten different gas treatments. An additional simulated retail display period of 7 days in air at 15 °C was also applied in all cases. These postharvest treatments were tested as an alternative to the usual industrial SO₂ application and included modified atmosphere packaging (MAP), with and without natural fungicides (hexanal and hexenal), controlled atmosphere (CA) and intermittent and continuous applications of ozone (O₃). The sensory quality was preserved with MAP of 13–16 kPa O₂ + 8–11 kPa CO₂, CA of 5 kPa O₂ + 15 kPa CO₂ and both O₃ treatments. Although O₃ did not completely inhibit fungal development, its application increased the total flavan‐3‐ol content at any sampling time. Continuous 0.1 µL L^?1 O₃ application also preserved the total amount of hydroxycinnamates, while all treatments assayed maintained the flavonol content sampled at harvest. Total phenolics increased after the retail period in O₃‐treated berries. MAP preserved the total polyphenol content, while a slight decrease was observed under the CA conditions used. Therefore the improved techniques tested for retaining the quality of ‘Autumn Seedless’ table grapes during long‐term storage seem to maintain or even enhance the antioxidant compound content. Copyright © 2007 Society of Chemical Industry     

Major flavan-3-ol composition and antioxidant activity of seeds from different grape cultivars grown in Turkey

The major flavan-3-ols composition and antioxidant activity of the seeds of 12 different common grape varieties that grow in Turkey were investigated. The quantities of gallic acid, catechin, epicatechin and total flavan-3-ol were determined with high performance liquid chromatography (HPLC) and spectrophotometric method in grape seeds extracts. Gallic acid, catechin, epicatechin and total flavan-3-ol varied from 18 to 101, 121–845, 85–893 and 4 507–13 360 mg/100 g in grape seeds, respectively. The seeds of Papaz Karası, Alicante Boushet and Kalecik Karası cultivars were good sources for these compounds among the cultivars examined. In most cultivars, the amount of epicatechin was greater than that of catechin. The cultivars that have high total flavan-3-ol content had the strongest free radical scavenging activities and results were shown that there is a highly significant correlation between the total flavan-3-ol content and antiradical efficiency (AE) (r=0.9168, P<0001).     

Assessing the performance of methods to detect and quantify African dust in airborne particulates

African dust (AD) contributions to particulate matter (PM) levels may be reported by Member States to the European Commission during justification of exceedances of the daily limit value (DLV). However, the detection and subsequent quantification of the AD contribution to PM levels is complex, and only two measurement-based methods are available in the literature: the Spanish-Portuguese reference method (SPR), and the Tel Aviv University method (TAU). In the present study, both methods were assessed. The SPR method was more conservative in the detection of episodes (71 days identified as AD by SPR, vs 81 by TAU), as it is less affected by interferences with local dust sources. The mean annual contribution of AD was lower with the TAU method than with SPR (2.7 vs 3.5 ± 1.5 μg/m(3)). The SPR and TAU AD time series were correlated with daily aluminum levels (a known tracer of AD), as well as with an AD source identified by the Positive Matrix Factorization (PMF) receptor model. Higher r(2) values were obtained with the SPR method than with TAU in both cases (r(2) = 0.72 vs 0.56, y = 0.05x vs y = 0.06x with aluminum levels; r(2)=0.79 vs 0.43, y = 0.8x vs y = 0.4x with the PMF source). We conclude that the SPR method is more adequate from an EU policy perspective (justification of DLV exceedances) due to the fact that it is more conservative than the TAU method. Based on our results, the TAU method requires adaptation of the thresholds in the algorithm to refine detection of low-impact episodes and avoid misclassification of local events as AD.