RESUMO
BACKGROUND: Defoliation is a cultural practice for crop management in grapevines and the benefits effects have been demonstrated. Here, the influence of 'early' leaf removal on the quality of Nero d'Avola wines was evaluated. Particular attention has been given to the volatile constituents responsible for the wine aroma but also to the total amount of polyphenolic compounds, anthocyanins and flavonoids. RESULTS: 'Early' defoliation was manually applied and compared with non-defoliated controls. The grapes were harvested at two different ripening times following their technological and phenolic maturity. Statistical quantitative differences occurred among the samples from the four trials (defoliated and control samples, both at two ripening times). Both the time of harvest and the vine leaf removal determined variation in the wine composition. A large number of volatile constituents were identified and quantified; the odour activity values (OAVs) were calculated. Basal leaf removal reduced pH and increased titratable acidity, total amount of anthocyanins, flavonoids, polyphenols and colour intensity in the wines from the first harvest. Results showed the increase of fermentation and varietal aromas in the defoliated wines from the first harvest. Limited differences occurred between the wines from defoliated and control vines relative to the second harvest. Principal components analysis, which was applied to compounds with OAVs ≥ 0.5, allowed the different compounds to be distinguished. CONCLUSION: 'Early' leaf removal can lead to a positive effect on the quality of Nero d'Avola under the environmental conditions in which the present study was undertaken but particular attention has to be given to the time of grape harvest. The results also demonstrate that 'early' defoliation can be applied to improve wine quality in the Mediterranean region, where there is a concentration of rainfall during winter, and nearly arid conditions and high temperatures during the summer.
Assuntos
Agricultura/métodos , Frutas/química , Odorantes/análise , Polifenóis/análise , Vitis/química , Compostos Orgânicos Voláteis/análise , Vinho/análise , Antocianinas/análise , Fermentação , Flavonoides/análise , Humanos , Fenóis/análise , Folhas de Planta/químicaRESUMO
Aqueous extracts from four different American hops varieties (Mosaic, Chinook, Citra, and Centennial) were produced using the Synergy Pure technique, an innovative extraction distillation process developed by Synergy Flavours, a global specialist in the manufacturing of flavors, extracts and essences. This process is able to preserve and maximize the aromatic characteristics without increasing the bitterness of the final product. Therefore, the aim of this work is to identify the volatile and sensory characteristics of these extracts, with the additional aim to assess their suitability for brewing. GC-MS and sensory analyses were carried out on the four different aqueous extracts. The results highlighted the presence of 33 volatile compounds in a quantity that allowed us to identify the characteristics of the varieties under investigation in each extract. Sensory analysis was carried out using the expert sensory profiling technique. The results regarding the olfactory analysis of the extracts allowed us to define the aroma profiles of the four extracts, highlighting their strong correspondence with the characteristic of the varieties under investigation. Finally, the results showed that the aqueous extracts produced using the Synergy Pure extraction technique had a richer aroma profile, highlighting its higher aptitude in beer production.
RESUMO
Party plates made of recycled paperboard with a polyolefin film on the food contact surface (more often polypropylene than polyethylene) were tested for migration of mineral oil into various foods applying reasonable worst case conditions. The worst case was identified as a slice of fried meat placed onto the plate while hot and allowed to cool for 1 h. As it caused the acceptable daily intake (ADI) specified by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) to be exceeded, it is concluded that recycled paperboard is generally acceptable for party plates only when separated from the food by a functional barrier. Migration data obtained with oil as simulant at 70°C was compared to the migration into foods. A contact time of 30 min was found to reasonably cover the worst case determined in food.