Search
Search Results
-
Evaluation of essential oils by gas-chromatography and a new method: "electronic nose"
85-89.Views:141The chemical quality of the essential oils is determined by their composition as well as by the complex aroma features. For the evaluation of odour and aroma, sensory tests are practised, especially for applications such as aromatherapy, food industry or perfumery. In the recent studies we investigated eight Mentha origins (populations of Mentha iperita, M. spicata and M. arvensis) of our genebank collection using a new and effective instrumental sensory evaluation method parallelly with the usual GC analysis.
The results show that the examined mint clones possess different essential oil accumulation levels and special flavour characteristics, too. The GC analysis of the essential oil revealed characteristic differences at both inter- and intraspecific level in the proportion of mentol, menthon, carvon, limonene, menthyl acetate and in two not identified monoterpenes.
In the sensory tests the special complex aroma enables a reliable distinction with a single exception among the populations by the help of the "electronic nose" equipment. The distinction among the samples based on the sensor signals of the instrument — evaluated by multivariate methods — shows a close relation with the detected monoterpene components of the essential oil.
-
Utilisation of nutrients by cucumber plants oil rockwool substrate
117-121.Views:106Cucumber production by soil less culture on rockwool substrate in Hungary is an open system regarding its water and nutrient supply. Environmental and economical reasons require the recycling of nutrients of the system. Experiments have been planned in order to estimate the utilisation of individual nutrient elements applied. All around the vegetation period, chemical analyses monitored the depletion of the elements initially administered by sampling the solutions at successive phases from the injection to the overflow. The results have been compared with earlier experiences refering to general rules. It has been stated that the intensity of photosynthesis is decisive in determining the composition of the overflow. The less changes are observed during the period of frequent watering.
The absorption of the nutrient elements varied between 25-51% deperiding on the individual elements. The differences are significant. Further examinations are needed in order to clear:
- which are the main elements of technology, which are decisive in utilisation of nutrients
- what are the possibilities of the secondary utilisation of nutrients.
-
Effect of organic and integrated farming on carotenoid and tocopherol content of apricot fruits
15-18.Views:203In modern and healthy diets antioxidants play an important role providing natural defence against serious diseases. Therefore it is recommended to include fruits and vegetables having high antioxidant capacity in daily diet in a due course. Apricot is one of the fruits receiving an increasing attention in this field. This study was conducted to investigate the composition and content of fat-soluble carotenoids and tocopherols in different varieties of apricot using recently developed liquid chromatographic methods. Also it was aimed to compare organic and integrated farming in their effect on carotenoid and tocopherol content of the fruits. The results showed that apricot fruit are rich in vital carotenoids and bioactive tocopherols with significant variation between different varieties. The organic farming had favourable effect on the level of the major carotenoids and depending on variety this technology either increases or does not have significant influence on vitamin E content.
-
Allelopathic effect of the Cladonia verticillaris lichen extracts and fumarprotocetraric acid on the early growth of germinating seeds and seedlings in Allium cepa L.
31-35.Views:152The allelopathic activity of the different extracts of the lichen Cladonia verticillaris and fumarprotocetraric acid on the early growth of A cepa (IPA 6) seedlings depends on their chemical composition and concentration, respectively. It was observed that the length of the radicle was significantly stimulated by fumarprotocetraric acid at high concentrations and by the total extract of C. verticillaris thalli, which contained a high level of fumarprotocetraric, acid confirmed by HPLC-technique. In addition, it was found, that the phosphate buffer extract, which contained high level of methyl (3-orcinol carboxilate measured by HPLC, reduced the length of the hypocotyls significantly. Under our experimental conditions there was no influence of the different types of extract and fumarprotocetraric acid on the ratio of seed germination, in relation to the control. From the study of HPLC it was found that fumarprotocetraric acid and methyl 13-orcinol carboxilate were present in all extracts at different concentrations, depending on the method of extraction.
-
Determination of biogenic amine - content of natural wines
91-95.Views:161Nowadays the consumption of natural wines has been increased. In parallel with the higher demand, the study of the parameters of natural wines has also developed. The amines being produced during the decarboxylization procedure of amino acids could be one of the most important features of natural wines. The objective of this study was to measure the biogenic amine content of natural wines from 2000 and 2001. We have determined that the biogenic amine content of natural wines is not different from the biogenic amine composition of normal wines. There was not any considerable difference between the years. In complience with the average tendency, red wines contain higher histamine-, tiramine- and serotonin values than white wines.
-
Ecological drought resistance and adaptability of apple varieties
113-122.Views:300For adequate yields in apple plantations, during the long growing period of the fruit primordia, one of the decisive factors is water supply. Indicators of stress are valuable signs for the diagnosis of drought and necessity of watering, i.e. planning the irrigation of plantations. The aim of the present study was to find reliable signs of water stress on apple trees and at the same time conclude on the drought tolerance of different varieties. The plantation of apple varieties grafted on various stocks and cultivated according to different systems (irrigated, non irrigated, integrate and biological) has been examined continuously by leaf analysis. Along the period of growing fruits, measurements were made in the field, then the leaf samples were analysed in the laboratory for composition of pigments, carbohydrates and antioxidants, as well as the histology of the tissues checked. Without irrigation, the mean leaf mass and the relative chlorophyll content (SPAD) of the variety Idared on M4 stocks increases beyond the values of 50 SPAD, whereas on M26 stock and integrated system, it declines. In the collection of varieties, grown according to the „integrated” system, during the development of fruits, ‘Gála’ and ‘Remo’ varieties have been affiliated to the “less susceptible” group regarding drought tolerance because of the leaf morphology, structure and content of SPAD and antioxidants. However, ‘Idared’ and ‘Jonagold’ belong to the “susceptible” group. To the same group are ranged the ‘Akane, Red Rome vanWell, Pink Lady’ varieties. Those varieties reacted to a short period of drought by increased production (content) of carbohydrates. Regarding changes of carbohydrate content ‘Greensleeves’ and ‘Ozark Gold’ varieties belong to the moderately water dependent (requiring) group. In the field, SPAD-tests facilitated the measurement of nutrient-uptake and incorporation, which is proved by the tight correlation between the data of SPAD and the increment of leaf weight (r=0.76–r=0.88), however, this depends on the variety too. SPAD is an indicator of water supply and is related with the density of stomata, cannot used for the selection of water-exigent varieties but for (drought) tolerant ones. In integrated culture, the (drought) susceptible varieties display (water-soluble) hydrophilic and lipophilic antioxidants (ACWand ACL resp.) the quantity of which may have some role in drought tolerance.
-
Change of Thiamine concentration and amino acid composition during sparkling wine base Production
62-66.Views:141It has been established, that thiamin content added in 3 mg/I concentration to musts before fermentation resulted in the enhanced storability of sparkling wine base at lower SO2 levels. Fermentation rate is not increased by this concentration and it causes no "thiamine taste" in organoleptic evaluation.
-
Evaluation of supercritical plant extracts on volatile and non volatile biologically active lipophil components
78-83.Views:133Authors dealt more than ten years with the analysis of supercritical extracts. For extraction (SFE) carbon dioxide was used as supercritical solvent. Fractionation of extracts was carried out by releasing the separations pressure at two stages. The extracts were collected as separate samples successively in time.
The traditional extractions were carried out with steam distillation or by using n-hexane and ethanol in Soxhlet apparatus. For the analysis of volatile compounds GC, GC-MS; of non volatile compounds TLC-densitometry and spectroscopic methods were used.
The following general characteristics were established comparing the composition of steam distillated oils with that of volatile SFE fractions. The SFE fractions were richer in monoterpene-esters and poorer in alcohols than the essential oils prepared by traditional way (clary sage, lavandel). Regarding the distributi,n of the monoterpene and sesquiterpene compounds, the SFE fractions contained sesquiterpene hydrocarbon in higher percentage than the distillated oils (e.g. 13-caryophyllene in Salvia fruticosa, (3-caryophyllene, ymuurolene, y-cadinene in Ochnum basilicum). Further the proportion of sesquiterpenes increased in SFE fractions collected successively in time.Significant difference was remarkable in respect of the optical rotationability of lovage oil and SFE fraction which was probably caused by the different ratio between the two ligustilid enantiomers. It was verified in some cases that a part of mono- and sesquiterpenes were present originally in a bounded form (glycosides) in plants. Therefore they appeared in essential oil fractions only after previous acidic treatment (Thymus, Origanum species). During the supercritical extraction the azulenogene sesquiterpene lactones did not transform to azulenes (in chamomile, yarrow), but the non volatile SFE fractions of some Asteraceae plant contained sesquiterpene--lacton of unchanged structure in high quantity (e.g. cnicin in blessed thistle, parthenolide in feverfew). Authors obtained also SFE fractions which were rich in triterpenoids and phytosterols (marigold, common dandelion).
-
Determination of biogenic amine content of Tokaj Wine Specialities
87-90.Views:141The knowledge of the finest composition of the Tokaj Wine Specialities is an indispensable task. The presence of the biogenic amines as an eventual combination of hygiene, technology and activity of Botrytis cinerea is a very important point of view in the future. The objective of this study was to measure the biogenic amine-content of Tokaj Wine Specialities.
According to our findings, the histamine-concentration remained lower than the prescribed end values, but ill the case of serotonine, there were significant measured values. During the fermentation period, in the first cycle there was a decrease in the concentration of biogenic amines, but with the advancement of fermentation, an increase was found.