The aim of this study was to investigate the effects of germination of spelt seeds under different stress conditions on the antioxidant characteristics of their extractable and bound phenolics. Germination under combined stress of 25 mM... more
The aim of this study was to investigate the effects of germination of spelt seeds under different stress conditions on the antioxidant characteristics of their extractable and bound phenolics. Germination under combined stress of 25 mM NaCl and 50 mM sorbitol without subsequent mechanical stress had considerable impact on total phenolics contents and scavenging activities against different free radicals (DPPH, ABTS+, O2-, ROO). Alkaline hydrolysis of extracts from germinated seeds provided the majority of their phenolic acids, where ferulic and p-coumaric acids were the most representative. The phenolics liberated from their bound form also had greater antioxidant activities. For the extractable phenolics, p-coumaric hexoside increased the most (146%), while among the bound phenolics identified, the highest relative increase was for p-coumaric acid (171%). The germinated seeds showed no effects on intracellular oxidation in cells of the yeast Saccharomyces cerevisiae.
Research Interests:
Chilies are widely cultivated for their rich metabolic content, especially capsaicinoids. In our study, we determined individual sugars, organic acids, capsaicinoids, and total phenolic content in pericarp, placenta, and seeds of Capsicum... more
Chilies are widely cultivated for their rich metabolic content, especially capsaicinoids. In our study, we determined individual sugars, organic acids, capsaicinoids, and total phenolic content in pericarp, placenta, and seeds of Capsicum annuum L., Capsicum chinense Jacq. and Capsicum baccatum L. by HPLC/MS. Dry weight varied in the cultivar ‘Cayenne’, with the first fruit having the lowest dry weight, with 4.14 g. The total sugar content and organic acid content did not vary among the fruits of all three cultivars. The cultivar ‘Cayenne’ showed differences in total phenolic and capsaicinoid content between fruits in the placenta, with the first fruit having the highest content of total phenolics (27.85 g GAE/kg DW) and total capsaicinoids (16.15 g/kg DW). Of the three cultivars studied, the cultivar ‘Habanero Orange’ showed the least variability among fruits in terms of metabolites. The content of dihydrocapsaicin, nordihydrocapsaicin, homocapsaicin, and homodihydrocapsaicin in th...
Research Interests:
A solid-phase extraction (SPE) technique was developed and optimised for isolation and concentration of extractable and bound phenolic acids from germinated spelt seeds, for analysis by liquid chromatography–mass spectrometry. Samples... more
A solid-phase extraction (SPE) technique was developed and optimised for isolation and concentration of extractable and bound phenolic acids from germinated spelt seeds, for analysis by liquid chromatography–mass spectrometry. Samples initially underwent solvent extraction under different conditions to maximise the yield of phenolic antioxidants. Optimal extraction conditions for extractable phenolics were absolute methanol as solvent, sample-to-methanol ratio 1:9, and reconstitution in non-acidified water. The bound phenolics were extracted from sample pellets using hydrolysis with 2 M NaOH, acidification of the hydrolysate with formic acid, and simultaneous isolation and purification using Strata X polymeric RP tubes. Compared to liquid-liquid extraction, this direct SPE protocol has significant advantages in terms of higher extraction efficiencies of total and individual phenolics and their antioxidant activities. These data suggest that direct SPE represents a rapid and reliable...
Research Interests: Medicine and Antioxidants
The brown marmorated stink bug (BMSB; Halyomorpha halys Stal.) has become a significant pest in Slovenia, especially in apple, pear, peach, and cherry orchards. In our study, apple fruit of the apple cultivar ‘Red Pinova’ were evaluated... more
The brown marmorated stink bug (BMSB; Halyomorpha halys Stal.) has become a significant pest in Slovenia, especially in apple, pear, peach, and cherry orchards. In our study, apple fruit of the apple cultivar ‘Red Pinova’ were evaluated for visual injury and sugar, organic acid, and phenolic contents. The chemical composition of the area around the puncture wound, the uninjured part of the infested apple, was compared to, as a control, only uninjured apples. There was a significant response of the apple around the puncture wound, resulting in an 11.9 g/kg FW higher total sugar content, a 1.4 g/kg FW lower total organic acid content, and an 11.9 g/kg FW higher total phenolic content compared with control apples. A strong phenolic response in the puncture wound area, with high flavanol and hydroxycinnamic acid contents, with increases of 118% and 237%, respectively, compared with control apples, was detected. The brown marmorated stink bug induces a strong phenolic response in the inj...
Research Interests:
Twenty-one different cultivars from four different species were examined. The highest dry weight was present in seeds (between 35 and 50%) and the average water content was 60%. Placenta and pericarp contained on average 86% water. Total... more
Twenty-one different cultivars from four different species were examined. The highest dry weight was present in seeds (between 35 and 50%) and the average water content was 60%. Placenta and pericarp contained on average 86% water. Total sugars variation between species was 60%. The most concentrated in the various cultivar pericarps were ascorbic acid ranging from 368.1 to 2105.6 mg/100 g DW and citric acid ranging from 1464.3 to 9479.9 mg/100 g DW. Total phenolic content ranged from 2599.1 mg/100 DW in ‘Chilli AS- Rot’ to 7766.7 mg/100 g DW in 'Carolina Reaper'. The placenta had 23.5 times higher phenolic content than seeds. C. chinense and C. chinense × C. frutescens had 3.5 to 5 times higher capsaicinoid content compared to C. annuum and C. baccatum, with 'Carolina Reaper' having the highest content at 7334.3 mg/100 g DW and 'Chilli AS- Rot' the lowest (318.7 mg/100 g DW).
Coffee and tea are popular beverages worldwide, and therefore generate large amounts of waste. Here we describe the caffeine content and phenolic profile in three types of teas and coffees, and how they vary with two successive... more
Coffee and tea are popular beverages worldwide, and therefore generate large amounts of waste. Here we describe the caffeine content and phenolic profile in three types of teas and coffees, and how they vary with two successive extractions. Although the first extraction was far more efficient than the second, green tea also showed a high content of flavanols in the second extraction, as did mate tea for phenolic acids. Black tea could also be a good option since caffeine content was highest in both extractions. Water also proved to be the most effective solvent in almost all cases, which represent a major benefit for urban horticulture, as it is a simple extraction method from an easily accessible source. Coffee and tea residues are a rich source of caffeine and phenolic compounds that could potentially be used as alternatives to conventional pesticides.
Research Interests:
ABSTRACT Export Date: 18 October 2014
Research Interests:
ABSTRACT Export Date: 18 October 2014
Research Interests:
The purpose of this study was to investigate composition and content of phenolic compounds in seeds of common buckwheat (Fagopyrum esculentum Moench) cultivars from Western, Central and Southeastern Europe grown in the Balkan area, and to... more
The purpose of this study was to investigate composition and content of phenolic compounds in seeds of common buckwheat (Fagopyrum esculentum Moench) cultivars from Western, Central and Southeastern Europe grown in the Balkan area, and to compare them with cultivars from the Balkan. Mostly detected hydroxycinnamic acids in seeds of the investigated cultivars were caffeic and chlorogenic acid derivatives. More than ten different flavanols were detected in the investigated seeds, based on which all tested buckwheat cultivars were divided into two groups: those with high propelargonidins (epiafzelechin-epicatechin) and those with high procyanidins contents. 'Novosadska' had the highest level of phenolic acids, proanthocyanidins, flavones and most of the flavonols. However, 'Bosna 1' and 'Bosna 2' were highlighted with the greatest rutin content (up to 46 times higher than in other cultivars). All buckwheat cultivars had quite high antioxidant capacity (more than...
Research Interests:
Cited By (since 1996):1, Export Date: 18 October 2014
Research Interests:
As a part of the ongoing interest in nutritional and nutraceutical properties of locally produced fruits, the aim of the article was to determine sugars, organic acids, polyphenols and antioxidant capacity of wild bilberries grown in... more
As a part of the ongoing interest in nutritional and nutraceutical properties of locally produced fruits, the aim of the article was to determine sugars, organic acids, polyphenols and antioxidant capacity of wild bilberries grown in Slovenia. Primary and secondary metabolite composition of bilberry fruit was compared among six phyto-climatic conditions, differing in photosynthetic active radiation and light intensity. Three sugars were quantified in bilberry fruit, the predominant being fructose and glucose, along with five organic acids. Bilberry fruit contained high levels of anthocyanins (cyanidin, delphinidin, malvidin, petunidin and peonidin glycosides), hydroxycinnamic acid derivatives and low levels of flavonol glycosides (mainly quercetin and myricetin glycosides), flavan-3-ols, proanthocyanidins and iridoids. The results of the study indicate that bilberries growing in sites with high photosynthetic active radiation (PAR) contained higher levels of total sugars, anthocyanins, flavonols and hydroxycinnamic acids and lower levels of organic acids compared with bilberry fruit from low-light locations. Consequently, total phenolic content and antioxidative capacity of the fruit from high-PAR locations were significantly increased. Bilberries from different natural habitats differ significantly in the quantity of sugars, organic acids and phenolic compounds. Our results contribute to a fuller understanding of the relationships between environmental factors and accumulation of primary and secondary metabolites in bilberry fruits.
Research Interests:
ABSTRACT The influence of exogenous indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on changes in the internal levels of IAA, indole-3-acetylaspartic acid (IAAsp) and antioxidant phenolics (chlorogenic acid and (-)-epicatechin)... more
ABSTRACT The influence of exogenous indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on changes in the internal levels of IAA, indole-3-acetylaspartic acid (IAAsp) and antioxidant phenolics (chlorogenic acid and (-)-epicatechin) was studied during the first 5 days of adventitious root formation in leafy cuttings of cherry rootstock 'GiSelA 5'. The highest free and conjugated IAA accumulations in the cutting bases were observed in the IAA treated cuttings, but that did not promote the percentage of cuttings rooted. During the first month of rooting, 43% of IAA treated cuttings and 30% of control cuttings developed roots. IBA gave the best propagation results, as 80% of cuttings formed roots during the first month of rooting. This indicates the influence of IBA on early root development, independently of IAA. Owing to different treatments, differences in the auxin levels caused no changes in the chlorogenic acid and (-)-epicatechin fluctuations; thus, in our experiment, their influence proved less important for root development than the chosen auxin application. (C) 2007 Elsevier B.V. All rights reserved.
Research Interests:
Phenolics in fruit may be influenced by the fruit type, cultivation conditions of a plant, climatic conditions, growing season, storage conditions, and industrial processing. The aim of this study was to compare single phenolic compounds,... more
Phenolics in fruit may be influenced by the fruit type, cultivation conditions of a plant, climatic conditions, growing season, storage conditions, and industrial processing. The aim of this study was to compare single phenolic compounds, total phenolics and antioxidant capacity of four varieties of apple grown under organic and integrated conditions over a 2-year period. Several different phenolic compounds belonging to the groups of hydroxycinnamic acids, flavanols, dihydrochalcones, flavonols and anthocyanins were quantified. The levels of all analysed groups of phenolics were higher (not always significantly) in the organically grown apple leaves and fruit than in the leaves or apples from integrated production. Leaves from organic trees had 10-20% higher content levels of total phenols than the leaves from trees in the integrated growing system. In both years, organic production affected the increase in the antioxidant activity of apple peel. Organic apples have higher total phenolic content than the integrated grown ones. Cultivation type had an important influence on the polyphenolic level and antioxidant capacity of the apple fruits and leaves. Apples from organic production showed a higher content of hydroxycinnamic acids, flavanols, dihydrochalcones, quercetins and total phenolics than apples from integrated cultivation.
Research Interests:
Research Interests: Chemical Engineering, Mass Spectrometry, Food, Agriculture, Food Chemistry, and 13 moreMultidisciplinary, Quantitative analysis, Identification, Fruit, High Pressure Liquid Chromatography, Plant extracts, Angiosperms, Food Sciences, Quantitative Analysis, Polyphenol, Flavonols, Glycosides, and HPLC Chromatography
ABSTRACT The aim of the present study was to estimate the influence of different rates of soil-applied nitrogen on leaf N and chlorophyll content and photosynthesis in 'Golden Delicious' apple trees. Three different... more
ABSTRACT The aim of the present study was to estimate the influence of different rates of soil-applied nitrogen on leaf N and chlorophyll content and photosynthesis in 'Golden Delicious' apple trees. Three different treatments were included: the trees were either fertilized with 80 kg N ha(-1) (N-80), 250 kg N ha(-1) (N-250) or left unfertilized (CON). Fertilization increased leaf nitrogen content, with a more prominent effect in high N application level treatment. In all treatments, a slight seasonal decrease in leaf nitrogen content was observed. N-250 treatment resulted in higher chlorophyll content; a similar effect was found late in the season for N-80 treatment. Measurements of A-C-i curves, performed on spur leaves, revealed a higher CO2 saturated photosynthetic rate in N-250 trees compared with low application level fertilized or unfertilized trees. No effect of N fertilization on carboxylation efficiency was found, as revealed by comparisons of the initial slopes of A-C-i curves. The lack of positive effect is rather surprising, since the leaf N content was efficiently increased with application of fertilizer. Obviously, the existing pool of leaf nitrogen in non-fertilized trees does not limit Rubisco activity and efficiency.
Research Interests:
Influence of foliar-applied phosphorus and potassium on
Research Interests:
This study evaluated the effect of preharvest treatments with salicylates (salicylic acid (SA), methyl salicylic acid (MeSA) and acetyl salicylic acid (ASA)) on fruit quality parameters and primary and secondary metabolites during... more
This study evaluated the effect of preharvest treatments with salicylates (salicylic acid (SA), methyl salicylic acid (MeSA) and acetyl salicylic acid (ASA)) on fruit quality parameters and primary and secondary metabolites during ripening at five sampling dates. The results showed that salicylates affect overall fruit quality, and some very desirable and important properties of strawberry fruits were acquired by the treatments, such as a deeper red colour (decreased hue angle), delayed ripening process with maintenance of higher fruit firmness, and higher sugar and ascorbic acid content. HPLC-MS analysis of the phenolic contents showed at almost all sampling dates that treatment with salicylates increased the content of some phenolic groups, the contents of the hydroxycinnamic acids (SA: up to 18%; MeSA: up to 13% increase), flavanols (SA: up to 27%, MeSA: up to 36% and ASA: up to 24% increase), anthocyanins (SA: up to 51%, MeSA: up to 33% and ASA: up to 28% increase) and also flav...
Effects of spraying over apple trees (Malus domestica; ‘Topaz’) with methyl salicylic acid (MeSA) and SA during fruit maturation were investigated for quality parameters (weight, firmness, hue angle, red blush, yield) and phenolic profile... more
Effects of spraying over apple trees (Malus domestica; ‘Topaz’) with methyl salicylic acid (MeSA) and SA during fruit maturation were investigated for quality parameters (weight, firmness, hue angle, red blush, yield) and phenolic profile of the peel and pulp (HPLC–mass spectrometry). These treatment effects were also investigated for activities of the phenylpropanoid pathway enzymes phenylalanine ammonia-lyase, chalcone synthase and isomerase (combined), and flavanone-3β-hydroxylase. The MeSA and SA treatments resulted in poor fruit peel coloration, with higher hue angles and 20% and 10% lower red blush, respectively. Anthocyanin levels were also significantly lower (56%) for MeSA treatment. MeSA stimulated activities of phenylalanine ammonia-lyase and chalcone synthase/isomerase, which resulted in higher levels of flavanols (to 34%), flavonols (to 33%), and hydroxycinnamic acids (to 29%), versus control. Therefore, while these salicylate treatments improve levels of some beneficia...
Research Interests:
Research Interests:
The objective of this work was to compare the contents of cyanidin glycosides and quercetin glycosides in the skin of apples grown with or without hail nets and using reflective foil or not. Under hail nets, photosynthetically active... more
The objective of this work was to compare the contents of cyanidin glycosides and quercetin glycosides in the skin of apples grown with or without hail nets and using reflective foil or not. Under hail nets, photosynthetically active radiation was 10% to 30% lower in comparison with the control treatment. Covering the orchard floor with reflective foil had a positive effect on lighting, particularly on the lower parts of the fruit. Fruit coloration depends on the contents of anthocyanins copigmented with flavonols, the synthesis of which is light-dependent. The content of the main cyanidin glycoside in ‘Fuji’ apple, cyanidin galactoside, was lowest in the control treatment as well as concentrations of cyanidin arabinoside and two other cyanidin pentosides. Reflective foil caused a higher cyanidin glycoside content. Among flavonols, quercetin galactoside, quercetin glucoside, quercetin pentoside, quercetin arabinofuranoside, quercetin xyloside, quercetin rutinoside, quercetin rhamnos...
Research Interests: Horticulture, Par, Color, Cultivar, Skin, and 6 moreKetone, Polyphenol, Ripening, Foil, Horticultural production, and climacteric
Prohexadione-calcium (ProCa), formulated as Regalis, was tested as a vegetative growth inhibitor in rejuvenated annual shoots of 14-year-old mother trees in the ‘Franquette’ walnut cultivar. ProCa was applied three times during growing... more
Prohexadione-calcium (ProCa), formulated as Regalis, was tested as a vegetative growth inhibitor in rejuvenated annual shoots of 14-year-old mother trees in the ‘Franquette’ walnut cultivar. ProCa was applied three times during growing seasons in 2005 (Y5) and 2006 (Y6). This was during the second half of spring growth flush, the resting phase between the first and second growth flushes, and in the middle of summer growth flush. As a result, treated shoots in the upper part of the canopy were shorter than untreated ones during the whole growing season in both years. In Y5, two treatments of ProCa (250 mg·L−1), applied until the middle of June, inhibited shoot elongation during summer growth, which was the main purpose of the experiment. The reduction of shoot elongation was between 18% [lower shoots in the canopy (LS)] and 33% [upper shoots (US)]. After three ProCa applications, also the final length of the shoots was reduced by 5% (US) and 18% (LS). In Y6, when 100 mg·L−1 of ProCa ...
Research Interests:
The concentration of major anthocyanins, quercetins, catechin, and phenolic acids during flower development of Rosa ×hybrida L. ‘KORcrisett’ was quantified using high-performance liquid chromatography/mass spectrometry. Additionally, the... more
The concentration of major anthocyanins, quercetins, catechin, and phenolic acids during flower development of Rosa ×hybrida L. ‘KORcrisett’ was quantified using high-performance liquid chromatography/mass spectrometry. Additionally, the changes in petal color were monitored colorimetrically at four different stages of development (bud, partially open flowers, fully open flowers, senescent flowers) and correlation was calculated between the chromaticity parameters and major/total anthocyanins. Color parameters a*, b*, and h° decreased with the progression of flower development and a*/b* ratio and lightness (L*) increased. In rose petals, a negative trend in the content of major (pelargonidin-3,5-di-O-glucoside, cyanidin-3,5-di-O-glucoside) and minor (pelargonidin-3-O-glucoside, cyanidin-3-O-glucoside, peonidin-3-O-glucoside) anthocyanins was observed during flower development. Buds contained almost threefold higher concentrations of pelargonidin-3,5-di-O-glucoside and fourfold highe...
Research Interests:
In the present study, the chemical and morphological status of eight cultivars of groundcover rose (Rosa ×hybrida) with a range of flower colors was investigated. From the methanolic extracts of rose petals collected from flowers at four... more
In the present study, the chemical and morphological status of eight cultivars of groundcover rose (Rosa ×hybrida) with a range of flower colors was investigated. From the methanolic extracts of rose petals collected from flowers at four developmental stages, several phenolic compounds were identified via high-performance liquid chromatography/mass spectrometry, including five anthocyanins, which are especially important for the visual attributes of rose flowers. Colorimetric parameters were also measured and correlated with total anthocyanins and cell sap pH levels. During flower development from bud to senescent stage, a significant trend was detected; lightness (L*) increased, b* decreased in all analyzed roses, and a* decreased in pink and red cultivars. Cell sap pH level increased from bud to senescent petals; fresh weight, dry weight, and water content increased to fully open stage and were then reduced in senescent petals. Total anthocyanin and quercetin content increased fro...
Research Interests:
Research Interests:
Research Interests:
The red color of skin is a much desired property in apple production. For better red fruit coloration the applications of foliar fertilizers on the basis of calcium and phosphorus are used. In the present study ‘Braeburn’ apple trees were... more
The red color of skin is a much desired property in apple production. For better red fruit coloration the applications of foliar fertilizers on the basis of calcium and phosphorus are used. In the present study ‘Braeburn’ apple trees were sprayed twice with Phostrade Ca (phosphorus), 5 and 3 weeks before harvest. In 7-days intervals fruit color, the content of flavonoids and enzyme activity involved in the synthesis of anthocyanins have been monitored. Foliar application of Phostrade Ca caused a more intense red skin color of apples and higher anthocyanin content. Their level increased during ripening, in treated apples the content of total anthocyanins was 20-fold higher at harvest while in control apples only 9-fold higher compared to the initial values. Cyanidin 3-galactoside was the most abundant anthocyanin (80 to 86% of total anthocyanins), followed by cyanidin 3-arabinoside, cyanidin 3-glucoside, cyanidin 3-xyloside and cyanidin 7-arabinoside. Prostrade Ca increased the level...
... Nutraceuticals and functional foods in health promotion and disease prevention. Acta Hort. 680:13-24. Shahidi, F., Alasalvar, C. and Liyana-Pathirana, CM 2007. Antioxidant phytochemicals in hazelnut kernel (Corylus avellana L.) and... more
... Nutraceuticals and functional foods in health promotion and disease prevention. Acta Hort. 680:13-24. Shahidi, F., Alasalvar, C. and Liyana-Pathirana, CM 2007. Antioxidant phytochemicals in hazelnut kernel (Corylus avellana L.) and hazelnut byproducts. J. Agric. Food Chem. ...
Research Interests:
The influence of foliar-applied phosphorus (P) and potassium (K) on leaf photosynthesis, transpiration and water use efficiency during the season was studied in Malus domestica 'Golden Delicious'. The research was carried out on... more
The influence of foliar-applied phosphorus (P) and potassium (K) on leaf photosynthesis, transpiration and water use efficiency during the season was studied in Malus domestica 'Golden Delicious'. The research was carried out on 14-year-old trees on M9 rootstocks. Trees were either sprayed with PK (Hascon M 10 AD), P (Radicon) or K fertiliser (Krad) or left unsprayed (control). PK spraying
Research Interests:
INFLUENCE OF COPPER COMPOUNDS ON THE CARBOHYDRATE CONTENTS IN DIFFERENT PARTS OF VINE (Vitis vinifera L.) The influence of copper (Cu) on synthesis of carbohydrate content in grapevine,(Vitis vinifera L.) cv. ‘Merlot’ was,tested in... more
INFLUENCE OF COPPER COMPOUNDS ON THE CARBOHYDRATE CONTENTS IN DIFFERENT PARTS OF VINE (Vitis vinifera L.) The influence of copper (Cu) on synthesis of carbohydrate content in grapevine,(Vitis vinifera L.) cv. ‘Merlot’ was,tested in Goriška brda,winegrowing,district. In 2003 three different
Research Interests:
Chlorogenic acid, epicatechin and rutin were analyzed in different cultivars of peach, apricot and sweet cherries. In peach and apricot the phenolics were analyzed in peel and pulp separately, while in sweet cherries the phenolics were... more
Chlorogenic acid, epicatechin and rutin were analyzed in different cultivars of peach, apricot and sweet cherries. In peach and apricot the phenolics were analyzed in peel and pulp separately, while in sweet cherries the phenolics were analyzed in the whole fruit only. The analyses were performed using high performance liquid chromatography with a diode-array detector. Differences in the contents of all phenolic compounds between the cultivars were distinguished. At peach and apricot varieties we noticed that the contents of chlorogenic acid, epicatechin and rutin were higher in peel compared to pulp. Therefore it can be suggested to the consumers that, regarding health promoting properties of fruit, unpeeled fruits should be eaten or used for processing. The highest values of chlorogenic acid, epicatechin and rutin were detected in apricot peel (on average 705.2, 86.3, 347.4 mg kg(-1) respectively). The highest values of analyzed phenolics in pulp were as follows: chlorogenic acid ...
The influence of black and white hall protection nets on apple cv. 'Jonagold' on yield, percentage of red blush on fruits, sunburn damage, photosynthesis, sugars and organic acids content was studied at the Fruit Growing Centre... more
The influence of black and white hall protection nets on apple cv. 'Jonagold' on yield, percentage of red blush on fruits, sunburn damage, photosynthesis, sugars and organic acids content was studied at the Fruit Growing Centre Maribor-Gacnik in 1998 and 2000. The orchard was planted in a single row system and trained as a slender spindle. Level of net photosynthesis in individual leaves under the covered and uncovered trees was not limited by lighting condition, but it was regulated with the amount of the yield. The nets influenced fruit colour in unfavourable conditions (high temperatures, little precipitation...). In 1998 only about 10% of fruits in all treatments had less than 10% blush area. In 2000 between 27.9% of fruits in the treatment without net and 46.6% of fruits under the black net had less than 10% of blush area. The share of blush area was higher on the fruits of uncovered trees and trees covered with the white net than on the fruits of the trees covered with...
Seasonal dynamics of the carbohydrates sorbitol, sucrose, glucose and fructose in fruits, leaves and bark and photosynthetic activity were followed in 12-year-old cv. 'Golden Delicious' apple (Malus domestica Borkh.) in response... more
Seasonal dynamics of the carbohydrates sorbitol, sucrose, glucose and fructose in fruits, leaves and bark and photosynthetic activity were followed in 12-year-old cv. 'Golden Delicious' apple (Malus domestica Borkh.) in response to defruiting in mid August. Photosynthetic activity of leaves decreased in the trees defruited in August compared to fruiting trees in the second half of August. In the mid-season, leaf carbohydrates were slightly but not significantly increased in defruited trees, which could suggest that the observed photosynthetic response is a result of sink-limitation. There were only minor differences observed when leaf, fruit and bark carbohydrates were compared for fruiting and defruited trees, which indicates that early defruiting in August did not significantly change carbohydrate translocation. Bark carbohydrates increased towards the end of the season, which underlines previous findings that the bark acts as a storage organ for spring growth in deciduous...
The aim of the experiment was to ascertain the dependence of the carbohydrates (sorbitol, sucrose, glucose and fructose) in fruits and leaves, organic acids in fruits, nitrogen content in leaves and leaf chlorophyll content according to... more
The aim of the experiment was to ascertain the dependence of the carbohydrates (sorbitol, sucrose, glucose and fructose) in fruits and leaves, organic acids in fruits, nitrogen content in leaves and leaf chlorophyll content according to the different rates of nitrogen supply. The analyses were conducted on 13-year-old cv. 'Golden Delicious' apple trees (Malus domestica Borkh.), which were either fertilized with 80 kg N ha(-1) (N-80) or 200 kg N ha(-1) (N-200) or not fertilized (N-0) as control. The leaf nitrogen content was significantly higher in the treatment N-200 than in the N-0 treatment. A seasonal decrease in leaf nitrogen content was noticed in all treatments. Leaf SPAD (indexed chlorophyll content) readings were increasing until the end of July and then stagnated. All over the season, the readings were significantly higher in treatment N-200 than in the N-0 treatment and from mid-June to end of July also higher than in the N-80 treatment. The nitrogen supply did not...
Endogenous phenolic compounds in walnut fruits were correlated with the severity of walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) as-sessed in the field, to determine the possible role of phenolics in resistance to... more
Endogenous phenolic compounds in walnut fruits were correlated with the severity of walnut blight caused by Xanthomonas arboricola pv. juglandis (Xaj) as-sessed in the field, to determine the possible role of phenolics in resistance to the disease. Healthy fruits of the cvs Franquette, Cisco, and Sampion with different susceptibilities to infection by Xaj were sampled from diseased trees three times during growth and analysed using HPLC with a PDA detector. An identical pheno-lic profile, consisting of juglone and six phenolic acids (ellagic, gallic, syringic, p-coumaric, caffeic, and chloro-genic), was detected in the studied cultivars. Juglone was the most abundant, ranging between 373 mg 100 g -1 and 5,074 mg 100 g -1 DW, compared to the least abundant caffeic and p-coumaric acids, which did not exceed 10 mg 100 g -1 DW. A negative correlation be-tween the total amount of phenolics present in the fruit tissues and blight severity was found in all cultivars, in-dicating the role o...
Research Interests:
Cited By (since 1996):1, Export Date: 18 October 2014
Antioxidant activity and polyphenols were quantified in vapour-extracted juice of nine Austrian, partially endemic varieties of sweet cherry (Prunus avium): cv.... more
Antioxidant activity and polyphenols were quantified in vapour-extracted juice of nine Austrian, partially endemic varieties of sweet cherry (Prunus avium): cv. 'Spätbraune von Purbach', cv. 'Early Rivers', cv. 'Joiser Einsiedekirsche', cv. 'Große Schwarze Knorpelkirsche' and four unidentified local varieties. Additionally the effect of storage was evaluated for six of the varieties. A variety showing the highest antioxidant capacity (9.64 μmol Trolox equivalents per mL), total polyphenols (2747 mg/L) and total cyanidins (1085 mg/L) was suitable for mechanical harvest and its juice did not show any losses of antioxidant capacity and total anthocyanin concentration during storage. The juice of cv. 'Große Schwarze Knorpelkirsche' had also high concentrations of total anthocyanins (873 mg/L), but showed substantial losses through storage. The local Austrian sweet cherry varieties from the Pannonian climate zone are particularly suitable for the production of processed products like cherry juice with high content of anthocyanins and polyphenols.
Research Interests:
Research Interests:
There are no defined maturity parameters for berry fruit which often results in harvesting and marketing of inedible, immature or over ripe berries. In the present study the changes in quality characteristics of different white-, red-,... more
There are no defined maturity parameters for berry fruit which often results in harvesting and marketing of inedible, immature or over ripe berries. In the present study the changes in quality characteristics of different white-, red-, and black-currant cultivars as well as gooseberry and jostaberry fruit were investigated at three maturity stages. Colour parameters, berry juice pH level and the content of sugars, organic acids and phenolic compounds have been evaluated. A total of 65 different phenolic compounds were detected by HPLC-PDA/MS. The results indicate that, during the last 2-4 weeks of fruit ripening, significant changes occur in colour parameters, primary and secondary metabolites and radical scavenging activity. The results suggest that the average content of specific phenolic groups and sugars/acids ratio can be used as a simple and reliable maturity index for optimisation of harvest time.
Research Interests:
Extreme weather events like high solar radiation can cause stress in apple fruits (Malus domestica Borkh.). The aim of the study was to make a screening of individual phenols and peroxidase activity in apple peel as a response to sunburn... more
Extreme weather events like high solar radiation can cause stress in apple fruits (Malus domestica Borkh.). The aim of the study was to make a screening of individual phenols and peroxidase activity in apple peel as a response to sunburn and different sun-exposures in the period when weather conditions are suitable for sunburn occurrence. Apple fruits of 'Golden Delicious' and 'Braeburn' were sampled. Fruit temperature and color were measured prior HPLC-MS(2) and peroxidase activity analyses. Sunburned peel was darker and more yellow-red in comparison to healthy peel, which appeared yellow-green. Fruit temperature, total as well as individual flavonols and dihydrochalcones, total hydroxycinnamics and perixodase activity were highest in sunburned peel in comparison with healthy sun-exposed peel, furthermore both were different than shaded sides of both fruits and peel of apples inside the tree crown; moreover in sunburned peel dihydrochalcones were determined for the first time. Chlorogenic acid was up to 2.5 times higher, 3-hydroxy-phloretin-2'-O-xyloglucoside was up to 10 times higher and quercetin-3-galactoside was up to 33 times higher in sunburned peel, comparing to shaded sided peels. Flavanols did not show a distinct pattern. A deeper insight in phenolic response against environmental stress caused by high solar radiation and high air temperatures has been made.
Research Interests:
ABSTRACT Dwarf French bean is cultivated in the open field, where unpredictable extreme weather events decreased crop yield quality. Hail net protection is therefore desirable. The pods are a rich source of sugars, organic acids and... more
ABSTRACT Dwarf French bean is cultivated in the open field, where unpredictable extreme weather events decreased crop yield quality. Hail net protection is therefore desirable. The pods are a rich source of sugars, organic acids and phenolic compounds and, as such, are an important nutritional vegetable. Due to consumer demand for half-sized pods in some traditional cuisines, the chemical profile of both pod sizes are desired. The aim of the study was to determine the effect of hail net covering on microclimatic conditions, specifically on light interception and temperature modification and, consequently, on the chemical profile of bean pods harvested in two sizes. The experiment was treated as a split–split plot designed three factorial experiment in four randomized replications. The main factor ‘covering’, had two levels, (hail net covered and uncovered plots); the sub-factor ‘cultivar’ had four levels, (‘Berggold’, ‘Re dei burri’ ‘Paulista’, ‘Top crop’) and the sub–sub-factor ‘pod size’, had two levels (half-size and full-size pods). Individual sugars and organic acids were analyzed, using high-performance liquid chromatography (HPLC). Total phenolic content was determined by spectrometry. Lighting was measured as the amount of photosynthetic active radiation (PAR). PAR under the hail net was reduced by 30–75% and mean daily temperature by 2.4 °C in comparison with the control. Significant genotypic effect was confirmed for vitamin C, while sugars, organic acids and total phenolics are affected mostly by interaction of two or three factors. Higher vitamin C content was found in cultivars classified as anthracnose resistant (‘Berggold’ and ‘Paulista’) compared to not resistant cultivars (‘Re dei burri’ and ‘Top crop’). Covering decreased fructose, glucose and vitamin C contents. Total phenolics were decreased under hail net only in pods of green pod cultivar. Hail net also influenced the composition of individual sugars in yellow pod cultivars (‘Berggold’ and ‘Re dei burri’), with which sweeter pods were harvested, with a higher fructose/glucose ratio. Pod size also significantly affected all chemical compounds analyzed bean pods. Younger half-sized pods had higher fructose and glucose content, as well as malic and citric acids and also total phenolic content, compared to full-sized pods. On the other side, younger pods contain significant lower amount of vitamin C and sucrose compared to older pods. Significant genotypic variation connected with hail net covering observed within yellow pod cultivars, provides opportunities for the plant breeders to develop special genotypes for maximizing the nutraceutical value of bean pods under hail net production.
Research Interests:
Page 1. ORIGINAL PAPER Polyphenol metabolism of developing apple skin of a scab resistant and a susceptible apple cultivar Ana Slatnar Maja Mikulic Petkovsek Heidi Halbwirth Franci Stampar Karl Stich Robert Veberic ...
Research Interests:
We studied the effect of prohexadione-calcium (Pro-Ca) on the content of hydroxycinnamic acids (chlorogenic acid, p-coumaric acid, ferulic acid and caffeic acid), flavonols (rutin, quercetin-3-O-rhamnoside), flavan 3-ols (catechin,... more
We studied the effect of prohexadione-calcium (Pro-Ca) on the content of hydroxycinnamic acids (chlorogenic acid, p-coumaric acid, ferulic acid and caffeic acid), flavonols (rutin, quercetin-3-O-rhamnoside), flavan 3-ols (catechin, epicatechin) and dihydrochalcones (phloridzin, phloretin) in the leaves and fruits of the scab resistant apple cultivar 'Florina' and the scab susceptible cultivar 'Jonagold'. Apple leaves were sampled 7 times at 2- day intervals after each Pro-Ca treatment. Fruits were harvested after the second Pro-Ca treatment six times during the growing season until their technological maturity. The phenolic compounds were detected using a HPLC system with a diode array detector at 280 and 350 nm. The antioxidant potential of apple pulp and peel, respectively, was measured with the DPPH (2,2-diphenyl-1-picrylhydrazyl) method and the total phenolic content in apple leaves and fruits was determined spectrophotometrically using the Folin-Ciocalteu ph...
Research Interests:
ABSTRACT Sugars, organic acids, vitamin C, individual phenolic compounds and total phenolic content were determined in fruit of 23 black currant cultivars with a different degree of infection caused by black currant leaf spot... more
ABSTRACT Sugars, organic acids, vitamin C, individual phenolic compounds and total phenolic content were determined in fruit of 23 black currant cultivars with a different degree of infection caused by black currant leaf spot (Drepanopeziza ribis) and septoria leaf spot (Septoria ribis) using HPLC analysis. Glucose and fructose were the most abundant sugars and the major organic acids were malic and citric acid. Four anthocyanin aglycones were identified in different black currant cultivars, i.e. cyanidin, delphinidin, petunidin and peonidin; their content was genetically dependant. Cultivars 'Brodtorp', 'Goliath', 'Pamyat Michurina' and 'Altajskaja Desertnaja' had the lowest infection rates (less than 5%) with spot diseases in both consecutive years (2011 and 2012) and can therefore be classified as resistant black currant cultivars. Generally, cultivars with severe symptoms of leaf spot infection also contained lower levels of total analyzed sugars in their fruit. High levels of hydroxycinnamic acids, epicatechin, and myricetin, kaempferol and quercetin glycosides were detected in cultivars with minimal symptoms of leaf spot infection. Cultivars with parental origin of the 'Goliath' and 'Brodtorp' types were classified as D. ribis and S. ribis resistant and cultivars of 'Baldwin', 'Boskoop Giant', 'Westra' and 'Victoria' group were leaf spot susceptible.
Research Interests:
ABSTRACT In a field experiment, the effectiveness and phytotoxicity of inorganic fungicides such as potassium bicarbonate (PBC) and sodium bicarbonate (SBC) were compared with water applications for the control and fungicide treatments as... more
ABSTRACT In a field experiment, the effectiveness and phytotoxicity of inorganic fungicides such as potassium bicarbonate (PBC) and sodium bicarbonate (SBC) were compared with water applications for the control and fungicide treatments as a classical method for controlling scab infections in cultivar ‘Braeburn’. To examine all possible effects of this inorganic fungicide disease severity, external quality parameters (mass, firmness, colour), and the content of primary and secondary metabolites were measured and recorded on fruit; and disease severity, the content of secondary metabolites and accumulation of potassium were monitored in apple leaves. The results indicate that both inorganic fungicides are effective against apple scab and do not cause any phytotoxicity at given application doses. External fruit quality parameters were comparable with fruit produced with fungicide treatments. Similarly, the PBC treatments exhibited a positive effect on higher content of sugars and organic acids in comparison to fungicide treatments. No significant differences between fungicide and PBC or SBC treatments were observed in the content of analysed phenolic compounds. The content of phenolic compounds in leaves, were comparable to those in fungicide treated trees. However, this only indicates the activity of defence mechanisms in apple leaves. The use of PBC also positively affected the potassium accumulation in leaves through the growing season. Given that these products are not toxic to human health, PBC and SBC can potentially present a perspective protection in the apple orchards especially for the control of apple scab in organic fruit growing.
Research Interests:
ABSTRACT
Research Interests:
ABSTRACT We studied the influence of covering the orchard floor with reflective foil on photosynthetic active radiation (PAR) both under and outside hail nets, and the possibility that the reflective foil under the hail net compensates... more
ABSTRACT We studied the influence of covering the orchard floor with reflective foil on photosynthetic active radiation (PAR) both under and outside hail nets, and the possibility that the reflective foil under the hail net compensates for light reduction in last month before harvest time. On the lower side of fruit in the canopy, the reflective foil increased PAR. The chromaticity value a* showed a difference in the intensity of red coloration in the reflective foil and hail net treatments. Amounts of individual cyanidins were detected by using HPLC-MS. The accumulation of five individual anthocyanins (cyanidin-galactoside, three cyanidin-pentoses and cyanidin) was investigated during last month before harvest time. Concentrations of the main, cyanidin-galactoside in 'Fuji' apple increased before harvest time, and at harvest time the reflective foil caused an increase in all identified anthocyanins. (C) 2007 Elsevier B.V. All rights reserved.
Research Interests:
ABSTRACT The correlation between the anthocyanin concentrations of seven Acer palmatum Thunb. cultivars and the chromaticity values a*, b*, a*/b* ratio, h degrees and L* was investigated. According to the position of leaves on the branch... more
ABSTRACT The correlation between the anthocyanin concentrations of seven Acer palmatum Thunb. cultivars and the chromaticity values a*, b*, a*/b* ratio, h degrees and L* was investigated. According to the position of leaves on the branch terminal, middle and base sample leaves were analyzed and the positional effect on the level of the major anthocyanin was estimated. Leaf color was measured with a portable colorimeter and individual anthocyanins were detected with the use of HPLC-MS. Cyanidin-3-glucoside was present in all senescing leaves of Acer cultivars and its content decreased from terminal to base position. Cyanidin-3-rutinoside was identified in lower concentrations in the leaves of all cultivars. Multiple variable analysis was calculated for each of the tristimulus values and two major anthocyanins (cyanidin-3-glucoside, cyanidin-3-rutinoside) in senescing leaves of ornamental Acer cultivars. Correlations were detected between the major anthocyanin (cyanidin-3-glucoside) in analyzed Acer cultivars and all chromaticity parameters. The highest correlation coefficient (0.94) was observed between cyanidin-3-glucoside and a*/b* ratio in cultivar 'Bloodgood' and lowest (0.54) between cyanidin-3-glucoside and a* in Acer palmatum Thunb. The correlation between cyanidin-3-rutinoside and chromaticity parameters was not detected in all Acer cultivars, additionally correlation coefficients and statistical significance were much lower. The expression of red color in both senescing leaves and in all-year-red cultivars can be tightly linked with the content level of cyanidin-3-glucoside: the second major anthocyanin does not contribute much to the red leaf color. (C) 2008 Elsevier B.V. All rights reserved.