The aim of this research was to evaluate the effect of a combination of several mycorrhizal and bacterial biostimulants, applied before and after planting, on the ‘Clery’ strawberry’s performance. Vegetative and reproductive parameters... more
The aim of this research was to evaluate the effect of a combination of several mycorrhizal and bacterial biostimulants, applied before and after planting, on the ‘Clery’ strawberry’s performance. Vegetative and reproductive parameters (the number of crowns per plant, root/canopy weight and dimensions, the number of fruits per plant, individual fruit weight, and fruit yield per plant) were monitored on nine harvest dates. Additionally, external and internal fruit quality (firmness, color, soluble solids content, and primary and secondary metabolites) was determined. The application of product combinations resulted in significantly improved vegetative growth, fruit dimensions, and fruit weight. Consequently, more than 30% higher yields were determined for the treated plants. A minor decrease in vitamin C (approx. 6%), total individual sugars (approx. 10%), organic acids (approx. 9%), and total phenolics (approx. 7%) was detected in the treated plants, but the differences were not uni...
Due to the increasing interest in highbush blueberry (Vaccinium corymbosum L.) among consumers, together with the problems of climate change and specific substrate requirements, a novel approach to intensive blueberry production is... more
Due to the increasing interest in highbush blueberry (Vaccinium corymbosum L.) among consumers, together with the problems of climate change and specific substrate requirements, a novel approach to intensive blueberry production is required. Here, ‘Duke’, ‘Aurora’, and ‘Brigitta’ blueberry cultivars were planted under the protective environments of a high tunnel and black hail net, each using ridge and pot planting systems. The high tunnel increased the maximal air temperature on average by 7.2 °C compared to the hail net. For all three cultivars, harvest began 6 to 18 days earlier under the high tunnel than under the hail net; however, lower yields and individual phenolics contents were obtained for the fruit. In ‘Aurora’ and ‘Brigitta’, environmental conditions under the high tunnel also reduced plant volume and fruit sugar/organic acid ratio. Growing blueberry plants in 60 L pots had no negative effects on plant volume and fruit ripening time, yield, firmness, color, and chemical...
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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...
Research Interests: Chemistry, Food Science, Sugar, Ascorbic Acid, Flavonols, and 3 moreRipening, Salicylic Acid, and Anthocyanin
Nitrogen is an integral element of foliar sprays during apple fruit formation. However, in red cultivars, the application may have adverse effects on color in the second stage of fruit development. The effect of a low-dose foliar... more
Nitrogen is an integral element of foliar sprays during apple fruit formation. However, in red cultivars, the application may have adverse effects on color in the second stage of fruit development. The effect of a low-dose foliar application of urea was monitored on ‘Topaz’ apple pomometric (fruit mass, firmness, total solids, starch content, skin color) and biochemical traits (primary metabolites, phenolic compounds, and assimilatory pigments). Three applications (17 July, 27 July, and 18 August) of two different urea doses (N1 = 1.4 kg N ha−1; N4 = 4 kg N ha−1) and control (N0, only sprayed with water) were used. Low doses of urea did not affect flesh firmness, total soluble, solid, and starch content, but individual fruit mass was significantly higher in N1 treatment compared to the other two treatments. Significantly lower a* parameters and a lower content of anthocyanins were measured on apples subject to N4 treatment. Many secondary metabolites (phenolic acids, flavan-3-ols, f...
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This study compares the individual phenolic response of husk tissues of Juglans regia L., infected to different degrees of severity with walnut anthracnose, which is one of the most serious and widespread walnut diseases worldwide. A... more
This study compares the individual phenolic response of husk tissues of Juglans regia L., infected to different degrees of severity with walnut anthracnose, which is one of the most serious and widespread walnut diseases worldwide. A comparison among three differently susceptible cultivars, ‘Franquette’, ‘Milotai 10’ (‘M10’), and ‘Milotai intenziv’ (‘M10-37’), is made. In our methodology, high performance liquid chromatography coupled with mass spectrometry is used to identify and quantify the compounds. Our results show that flavanols, flavonols, and naphthoquinones account for more than 95% of the phenolic compounds identified in the walnut husk. The higher total analyzed phenolic content in tissues is more affected by walnut anthracnose confirmed that phenolics play a major role in the plant’s response against pathogens. A difference between cultivars is observed, since French cultivar ‘Franquette’ responds differently to walnut anthracnose infection than Hungarian cultivars ‘M10...
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The present study was designed to identify and quantify the major phenolic compounds (phenolics) in the inner and outer husks, buds and bark of the Persian walnut, Juglans regia L. A comparison across six different cultivars grown in... more
The present study was designed to identify and quantify the major phenolic compounds (phenolics) in the inner and outer husks, buds and bark of the Persian walnut, Juglans regia L. A comparison across six different cultivars grown in Slovenia was also carried out: ‘Fernor’, ‘Fernette’, ‘Franquette’, ‘Sava’, ‘Krka’ and ‘Rubina’. A total of 83 compounds were identified, which included 25 naphthoquinones, 15 hydroxycinnamic acids, 8 hydroxybenzoic acids, 13 flavanols, 2 flavones, 1 flavanone and 19 flavonols. For the first time, 38 phenolics in the husks, 57 phenolics in the buds and 29 phenolics in the bark were presented in J. regia within this study. Naphthoquinones were the major phenolics determined, approximately 75% of all analysed phenolics in the inner husk, 85% in the outer husk, 50% in buds and 80% in bark. The highest content of phenolics was found in the walnut buds, followed by the bark, the inner husk and the outer husk. On the basis of these high phenolic contents, waln...
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The influence of two foliar applications of Phostrade Ca, which contains high concentrations of phosphorus and minor amounts of calcium and nitrogen, on color development and selected primary and secondary metabolites was investigated... more
The influence of two foliar applications of Phostrade Ca, which contains high concentrations of phosphorus and minor amounts of calcium and nitrogen, on color development and selected primary and secondary metabolites was investigated during advanced maturation of ‘Braeburn’ apple. Changes of hydroxycinnamic acids, flavanols, dihydrochalcones, flavonols, and anthocyanins were monitored six times during the advanced ripening until technological maturity of the fruits. Additionally, the changes in the chromatic values a*, h°, and the lightness coefficient L* were recorded weekly. The colorimetric parameters showed a significant difference in the intensity of red coloration between the treated and untreated apples. Spraying with Phostrade Ca also resulted in a significant increase in most individual sugars, total sugars, and concentration of anthocyanins and flavonols. Moreover, the amount of phosphorus (P) in the treated leaves was increased. However, the total phenolic content and ac...
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A rare walnut variant with a red seed coat (pellicle) was examined for alterations in its phenolic profile during development. The red-walnut (RW) pellicle was compared with two commonly colored walnut varieties: 'Lara' (brown)... more
A rare walnut variant with a red seed coat (pellicle) was examined for alterations in its phenolic profile during development. The red-walnut (RW) pellicle was compared with two commonly colored walnut varieties: 'Lara' (brown) and 'Fernor' (light brown). Furthermore, the activities of selected enzymes of the phenylpropanoid- and flavonoid-related pathways and the relative expressions of the structural genes phenylalanine ammonia lyase ( PAL) and anthocyanidin synthase ( ANS) were examined in the pellicles of the three varieties. In the pellicles of the RWs, phenylalanine ammonia lyase (PAL) activity and related PAL expression was most pronounced in August, about one month before commercial maturity, suggesting a high synthesis rate of phenolic compounds at this development stage. The most pronounced differences between the red and light- and dark-brown varieties were the increased PAL activity, PAL expression, and ANS expression in RWs in August. The vibrant color o...
Research Interests: Engineering, Biochemistry, Genetics, Microbiology, Chemistry, and 15 moreDevelopmental Biology, Immunology, Molecular Biology, Medicine, NUTS, Juglans, Anthocyanins, CHEMICAL SCIENCES, Phenols, Phenylalanine, ANS, Phenolic, Phenylalanine ammonia lyase, Gene expression profiling, and Chalcone synthase
The occurrence of the abscission signal in young developing fruits on apple trees (Malus domestica) was studied. Apple has a natural system of fruitlet shedding, so called June drop. Although physiological fruit drop is unable to... more
The occurrence of the abscission signal in young developing fruits on apple trees (Malus domestica) was studied. Apple has a natural system of fruitlet shedding, so called June drop. Although physiological fruit drop is unable to guarantee production of marketable apples and avoid alternate bearing, knowledge of this is a key background for successful fruit thinning. A study was carried out on apple trees cv. ‘Golden Delicious’ during June drop. On three dates (beginning, middle and after June drop), the daily dynamics of HPLC detected individual sugar and spectrophotometrically detected total phenolic contents were investigated in central (K) and lateral (L) fruitlets. The results of daily dynamics showed the highest sugar contents at 2 p.m. On the final sampling date, on 2nd July 2015, we observed a significant difference between sugar contents at 2 p.m. and the morning and afternoon measurements. Contents of sugars in K and L fruitlets were not significantly different. Total phen...
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High temperature stress, which has been occurring more often in recent years, usually coincides with the flowering of primocane raspberries and causes a negative effect on fruit quality parameters. One of the methods of delaying raspberry... more
High temperature stress, which has been occurring more often in recent years, usually coincides with the flowering of primocane raspberries and causes a negative effect on fruit quality parameters. One of the methods of delaying raspberry flowering and fruit development to avoid high summer temperatures is tipping the young primocanes. The aim of the study was to investigate how this practice affects the fruit characteristics and primary and secondary metabolites of two primocane raspberry cultivars (‘Amira’ and ‘Polka’). For this purpose, we performed primocane tipping on two different dates in late spring and analyzed the berries from three subsequent sampling dates. High performance liquid chromatography-mass spectrometry (HPLC-MS) analyses were used for the identification and quantification of individual phenolic compounds and HPLC analyses for individual sugars and organic acids. Primocane tipping had great influence on the beginning of the harvest season of both cultivars. The...
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ABSTRACT Qualitative and quantitative changes of individual and total phenolics induced by Colletotrichum coccodes fungal infection have been studied in two susceptible sweet pepper cultivars ‘Soroksari’ and ‘Bagoly’, and the role of... more
ABSTRACT Qualitative and quantitative changes of individual and total phenolics induced by Colletotrichum coccodes fungal infection have been studied in two susceptible sweet pepper cultivars ‘Soroksari’ and ‘Bagoly’, and the role of soluble phenolic compounds in plant's defence mechanism has been evaluated. Three distinct parts were analysed on pepper fruit: healthy tissue, anthracnose lesion, and bordering tissue, and individual phenolic compounds have been identified with the use of HPLC-MS system. In pepper fruit pericarp 21 phenolic compounds have been determined; the prevalent apigenin, quercetin and luteolin glycosides, chlorogenic acid and one chrysoeriol glucoside. C. coccodes infection increased the accumulation of chlorogenic acid, chrysoeriol glucoside, quercetin and luteolin glycosides in infected bordering tissue of both analysed pepper cultivars compared to healthy pepper tissue or symptomatic spot. Total apigenin derivatives did not show a significant increase in bordering tissue compared to the healthy pepper fruit in contrast to other groups of phenolics. This suggests a lesser role of apigenin glycosides in pepper plant defence against the Colletotrichum fungus. Intense phenolic synthesis was characteristic for the bordering zone between the healthy and infected plant tissue resulting in higher total phenolic content which might hinder the fungus to spread from the infected cells into the healthy tissue.
Research Interests: Botany, Microbiology, Plant Biology, Biology, Pepper, and 4 moreQuercetin, Chlorogenic Acid, Apigenin, and luteolin
Research Interests: Engineering, Mathematics, Chemistry, Horticulture, Irrigation, and 15 moreFlavonoids, Medicine, Antioxidants, Humans, Food Quality, Crop Production, Cultivar, Fruit, Deficit Irrigation, Dietary Carbohydrates, Conservation of Natural Resources, Agricultural Irrigation, Fragaria, Nutritive Value, and Hydroxy acids
The distribution of betalains in peel, flesh, and petioles of yellow and red beetroot cultivars has been investigated using an High-performance liquid chromatography (HPLC) system with electrospray mass spectrometry. Differences in the... more
The distribution of betalains in peel, flesh, and petioles of yellow and red beetroot cultivars has been investigated using an High-performance liquid chromatography (HPLC) system with electrospray mass spectrometry. Differences in the levels of betacyanins and betaxanthins between different colored cultivars were individually determined for 3 plant parts. The content of almost all analyzed compounds decreased in the following order: peel > flesh > petiole. Betanin/isobetanin pigments comprised a major portion of the relative peak area measured in red beetroot peel. Isobetanin relative peak areas were also high in leaf petioles (68.94% to 74.16%) of red colored cultivars. However, betacyanins were completely absent from the extracts of all analyzed parts of yellow beet. Glutamine-bx represented a very high relative peak area (59.54% to 64.18%) in flesh of red-colored cultivars analyzed in the study. Our results indicate that red beet cultivars can be utilized as a potential source of red and yellow natural colorants. However, differences in pigment composition among different beetroot parts must be considered and in order to maximize the pigment yields petioles can also be used as a source rich in specific betalain compounds.
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Persimmon is a seasonal fruit and only available in fresh form for a short period of each year. In addition to freezing, drying is the simplest substitute for the fresh fruit and accessible throughout the year. The effect of mellowing and... more
Persimmon is a seasonal fruit and only available in fresh form for a short period of each year. In addition to freezing, drying is the simplest substitute for the fresh fruit and accessible throughout the year. The effect of mellowing and drying was evaluated in 'Tipo' persimmon, an astringent cultivar. 'Tipo' firm fruit contained high levels of tannins (1.1 mg g(-1) DW), which were naturally decreased to 0.2 mg g(-1) DW after mellowing. The drying process greatly impacted the contents of carotenoids, total phenols, individual phenolics, tannins, organic acids, sugars and colour parameters in firm and mellow fruit. The reduction of tannins, phenolic compounds and organic acids were accompanied by the increase of sugars and carotenoids, improving the colour of the analysed samples. These results showed that the drying process improved the quality of persimmon products and extended their shelf life. © 2015 Society of Chemical Industry.
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Prohexadione-Ca (ProCa) was applied in an adult walnut orchard of cv. Franquette to test its ability to reduce severity of Xanthomonas arboricola pv. juglandis (Xaj) infection, and the effect on the contents of phenolic compounds in... more
Prohexadione-Ca (ProCa) was applied in an adult walnut orchard of cv. Franquette to test its ability to reduce severity of Xanthomonas arboricola pv. juglandis (Xaj) infection, and the effect on the contents of phenolic compounds in walnut fruits. ProCa was used three times over at 8-10 day interval, starting before the stigmas emergence at 0.125 mg l-1 concentration (treatment R1), and at the stage of brown stigmas at 0.250 mg l-1 concentration (treatment R2). Blight severity was assessed within the orchard at the same time as the husk tissues from symptomatic fruits were sampled for phenolic analyses, which were conducted using HPLC with PDA and MS detection. ProCa caused a significant reduction in Xaj severity regardless of the concentration and the first application date. The induced defence reaction was maintained throughout the season. Within a 15-day interval after the ProCa treatments, the walnut husks showed up to a 14 fold higher content of different phenolics than before ...
Research Interests: Horticulture, Plant Biology, Biology, Gallic acid, Plant Pathology, and 3 moreFlavonols, Orchard, and husk
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A total of 19 different anthocyanins have been detected in four elderberry species and eight hybrids and quantified with the use of HPLC-MS(n). The profile and content levels of anthocyanins varied considerably among the analyzed... more
A total of 19 different anthocyanins have been detected in four elderberry species and eight hybrids and quantified with the use of HPLC-MS(n). The profile and content levels of anthocyanins varied considerably among the analyzed elderberry species and hybrids. Cyanidin-3-O-sambubioside and cyanidin-3-O-glucoside were the most abundant anthocyanins in Sambucus nigra fruits. On the other hand, the prevalent anthocyanin in S. javanica hybrids was identified as cyanidin-3-(E)-p-coumaroyl-sambubioside-5-glucoside. The highest content of total analyzed anthocyanins (TAA) was determined in berries of the interspecific hybrid S. javanica × S. racemosa, followed by S. nigra, (S. javanica × S. nigra) × cv. Black Beauty, and (S. javanica × S. nigra) × S. cerulea. Berries of S. nigra var. viridis contained significantly lower levels of TAA. Our results provide novel information for nutritional research in addition to breeding programs, which strive to create new hybrids or cultivars with enhanced levels of bioactive components.
Research Interests: Engineering, Botany, Mass Spectrometry, Biology, Medicine, and 13 moreAntioxidants, Hybrid, Fruit, Anthocyanins, High Pressure Liquid Chromatography, CHEMICAL SCIENCES, Sambucus Nigra, Interspecific competition, Agricultural and Food Chemistry, Anthocyanin, Interspecific hybrids, Sambucus, and cyanidin
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 ...
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ABSTRACT The concentration of anthocyanins, chlorophyll a and b were quantified during bract development of three differently colored Euphorbia pulcherrima Willd. cultivars ('Mars White', 'Mars Pink', and... more
ABSTRACT The concentration of anthocyanins, chlorophyll a and b were quantified during bract development of three differently colored Euphorbia pulcherrima Willd. cultivars ('Mars White', 'Mars Pink', and 'Mira Red') and bract color was colorimetrically determined. Color parameter a* increased from the first analyzed stage of bract development to the subsequent stages in all poinsettia cultivars. Chlorophyll a predominated over chlorophyll b in partially pigmented bracts and a sharp decrease in chlorophyll a content was detected in fully pigmented bracts. Eleven different anthocyanic pigments were identified with the use of high-performance liquid chromatography/mass spectrometry (HPLC/MS). The predominant cyanidin-3-galactoside, cyanidin-3-glucoside, cyanidin-3-rutinoside, pelargonidin-3-glucoside and pelargonidin-3-rutinoside were also detected in white and pink poinsettia bracts. Anthocyanin content levels increased significantly with the transition from partially to fully pigmented bracts in all analyzed cultivars and their accumulation coincided with the arrest of photosynthetic pigments synthesis.
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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.
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... Table 1. Optimised conditions for assays of main enzymes of the flavonoid pathway in apple peel. ... Different letters (a, b, c) denote statistically significant differences between different parts of peel. Around spot, Spot, Healthy,... more
... Table 1. Optimised conditions for assays of main enzymes of the flavonoid pathway in apple peel. ... Different letters (a, b, c) denote statistically significant differences between different parts of peel. Around spot, Spot, Healthy, LSD a (df = 8). ...
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The influence of cultivar and picking date on the phenolic content of walnut liqueur was investigated using HPLC with a PDA detector. Ten phenolic compounds, namely gallic, protocatechuic, ellagic, chlorogenic (5-caffeoylquinic),... more
The influence of cultivar and picking date on the phenolic content of walnut liqueur was investigated using HPLC with a PDA detector. Ten phenolic compounds, namely gallic, protocatechuic, ellagic, chlorogenic (5-caffeoylquinic), syringic, p-coumaric and sinapic acids, as well as (+)-catechin, 1,4-naphthoquinone and juglone were detected. The walnut liqueur under analysis was made of the cultivars ‘Franquette’ and ‘Elit’, on two
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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...
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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: Horticulture, Biology, Medicine, Plants, Sugar, and 3 moreCultivar, Capsicum Chinense, and Dry Weight
Background Biostimulants, such as algae extracts or amino acids, are becoming more common in agriculture because the mentality is to make plants more resistant or tolerant to negative environmental factors, rather than using synthetic... more
Background Biostimulants, such as algae extracts or amino acids, are becoming more common in agriculture because the mentality is to make plants more resistant or tolerant to negative environmental factors, rather than using synthetic chemicals (herbicides, insecticides and fungicides), whose use is decreasing year by year, forcing farmers and companies to develop new environmentally friendly products. Results In a field experiment, green algae and amino acids were tested as biostimulants on three hot pepper cultivars. A large variability was observed between the effects of the two biostimulants on the cultivars. Green algae-treated ‘Somborka’ and ‘Habanero Red Caribbean’ cultivars had 10% and 5% higher dry matter in seeds compared to control treatment. Total sugar content was negatively affected by green algae extract and amino acids in pericarp in cultivars ‘Chili AS-Red’ and ‘Habanero Red Caribbean’. Total organic acids content was positively affected by amino acid treatment in ‘...
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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.
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The production system, especially fertilisation has an important effect on yield and quality of strawberries. In the present study, plants were fertilized with different doses of nitrogen (0–100% recommended doses), calcium chelate, as... more
The production system, especially fertilisation has an important effect on yield and quality of strawberries. In the present study, plants were fertilized with different doses of nitrogen (0–100% recommended doses), calcium chelate, as well as nano fertilizer Lithovit. Strawberry cultivar ‘Clery’ yield and quality parameters (fruit color and firmness) including nutritional indicators (total soluble solids, sugars, organic acids, phenolic and volatile compounds) were monitored. Volatiles were identified and monitored using headspace solid phase microextraction and analysed using gas chromatograph-mass spectrometry (SPME/GC-MS) and sugars, organic acids, and phenolic compounds with high performance liquid chromatography. Organic acids and phenolic compounds were detected with mass spectrometer (HPLC/MS). Both nitrogen and calcium fertilisation had altered sugars, organic acids, volatile and phenolic contents in strawberry fruits. Fertilisation with higher doses of nitrogen and calcium...
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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...
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Research Interests: Chemistry and Agriculture
Phenolic compounds are not directly involved in the primary metabolism of plants but possess a number of important roles: (1) serving as attractants for pollinators and various animals, involved in the transfer of seeds, (2) plant... more
Phenolic compounds are not directly involved in the primary metabolism of plants but possess a number of important roles: (1) serving as attractants for pollinators and various animals, involved in the transfer of seeds, (2) plant protection from herbivores and against pathogen infection, (3) defining plant-plant relationships and the symbiosis between plants and microbes. The present review of our research work stresses the role of phenolic compounds in the defense mechanism against different fungi and bacteria. It has been established, that the content of phenolics is greatly affected by the infection with pathogenic organisms. Studies on several horticultural plants have demonstrated that the response to infection differs among the analyzed plant species. Generally, an increase of phenolic compounds can be expected in tissues near the infection site. The comparison of healthy and infected tissue reflects an increase of phenolics in infected tissues. Higher levels of all analyzed ...
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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...
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ABSTRACT Export Date: 18 October 2014
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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.
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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.
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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.
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ABSTRACT The phenolic profile of healthy and infected raspberry canes was investigated in three raspberry cultivars: Autumn Bliss, Himbo Top and Polka. The content of total phenols and tannins was determined using spectrophotometric... more
ABSTRACT The phenolic profile of healthy and infected raspberry canes was investigated in three raspberry cultivars: Autumn Bliss, Himbo Top and Polka. The content of total phenols and tannins was determined using spectrophotometric methods, whilst individual phenolic acids, flavan-3-ols, ellagic acid derivatives and glycosides of quercetin were analysed using HPLC/MS analysis. The content of secondary metabolites varied considerably among the analysed raspberry cultivars. Moreover, Didymella applanata and Leptosphaeria coniothyrium infection significantly altered the metabolism of phenolic compounds. Flavanols represented the greatest share of all identified phenolics in raspberry canes (90%), followed by glycosides of quercetin (6%), derivatives of ellagic acid (3%) and traces of hydroxycinnamic acid derivatives. Spur and cane blight diseases caused an increase of flavan-3-ols and tannins but the levels of hydroxycinnamic acid derivatives, conjugates of ellagic acid and quercetin glycosides were significantly reduced. Cultivars Himbo Top and Polka contained higher levels of hydroxycinnamic acid and ellagic acid derivatives in healthy and infected canes compared to cv. Autumn Bliss. Cultivar Polka also contained the highest level of flavanols and tannins. However, despite high levels of flavanols and total phenols measured in cv. Polka, the canes were highly diseased following infection with D. applanata and L. coniothyrium. The results of the study provide evidence that the level of phenolic compounds in the canes could be causally linked to the differences in disease susceptibility.
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The study focuses on the response of apple primary and secondary metabolism and some important quality parameters to three living mulch treatments, classical herbicide fallow, and black polypropylene strip application in two apple... more
The study focuses on the response of apple primary and secondary metabolism and some important quality parameters to three living mulch treatments, classical herbicide fallow, and black polypropylene strip application in two apple cultivars. Primary and secondary metabolites were analyzed after 10 years of ground cover experiments. Soluble solids, firmness, and color measurements indicate differences among orchard floor management treatments. Significantly, lower levels of individual sugars have been measured in fruit of different living mulch treatments compared with fruit harvested from trees subjected to the herbicide strip treatment. Total sugar content was higher in fruit of the herbicide strip treatment in both cultivars analyzed. Significantly higher levels of total organic acids were only detected in 'Pinova' fruit of the Festuca ovina L. treatment. Long-term response of both cultivars to living mulch treatments indicated that apples increase the accumulation of almost all analyzed individual phenolic compounds.