The Dynamic Of Essential Oil Accumulation In Hop Cones During 2011 Year

The present study includes researches regarding th e dynamic accumulation of essential oil in hop cones, in different phenophases: during the formation, ripening and harvesting cones. The study was carried out for three varieties of hop: Magnum (MG), Huller Bitterer (HB) and Aroma (AR), cultivated in pedo-climatic areas from Transi lvania, in the Seleu s farms from Mure s. The essential oils were extracted from all samples usin g the hydrodistillation technique. Introduction. Hop ( Humulus lupulus L.) plants are vital to the brewing industry (Jelinek et.al, 2010). The lupulin glands of the ho p cones contain a resinous fraction and essential oil which is responsible for the bitter t aste of beer and also contributes to its flavour (Shellie et.al, 2009).The identification of the hop cultivar is a very actual question as well as the development of methods suited for this purpose. Some authors proposed identification methods based only on the specific contents of the selected essential oils (Kovacevic et.al, 2002, Jelinek et.al, 2010). The therapeutic or othe r properties of essential oils are strongly correlated with their qualitative and quantitative composition (Tofana et.al, 2010). Aims and objectives. The purpose of the present work was to study the d ynamic accumulation of essential oil in hop cones, in diff erent phenophases: during their formation, ripening and at harvesting, but also during cones p rocessing (pellets). Samples from 2011 year crop were subjected to hydrodistillation in or der to content in essential oils. Materials and method. The study of volatile oil dynamic accumulation in cones was carried out for three varieties of hop: Magnum (MG), Huller Bitterer (HB) and Aroma (AR), in different phenophases: during the formatio n, ripening and harvesting.The samples of hop cones were collected from Seleu s farms from Mure s, a traditional Romanian hop grower, during 2011 year. Traditional classification of hop cultivars divides them into three groups: Magnum- high α-acid, Huller Bitterer -intermediate α-acid and Aroma- an aroma (noble) variety.The hop cones were air dried for 48 hours, in a cool dark place, after being labeled and stored until the analyses. The pellets samples were received from the farm, but the grower do not process Aroma cones into pellets, because this hop cultivar is grown on a small area and the cones are combined with the ones from other aro matic varieties. The samples were codified as follows: MG, AR, HB-variety of hop, Ceo (essential oil from dried cones), Feo (essential oil from hop flower),Peo (essential oil from pellets). Samples of hop essential oil were isolated by hydrodistillation: 50 g of ground hop cones/ hop pellets (ground in a coffee mill) were weighed into a 700 ml distillation flask . The distillation time was 3 hours since the distillation begins. At the end of extraction the o btained essential oil was collected and measured. Yield was calculated as ml essential oil per 100g plant material free of moisture. Relative accumulation is calculated from the total oil determined in cones, and it shows the percentage differences of oil accumulation during p henophases. Relative increase shows the percentage growth between phenophases and is calculated by the difference between phenophase 2 and 1, respectively phenophase 3 and 2.