Publications by authors named "Maja Mikulic-Petkovsek"

An HPLC-MS-DAD analysis of phenolic compounds was carried out on the extracts of staghorn sumac ( L.) and Himalayan balsam ( Royle). This study focuses on the influence of solvent type and extraction time on the phenolic extraction efficiency from both invasive plants.

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Ultrasound and microwave maceration techniques have been utilised to lower production costs and reduce processing time, while also preventing the degradation of nutrients like phenolics and vitamin C and preserving physical properties such as colour and viscosity. In this study, the effects of several traditional (cold, enzymatic, and thermal) and innovative (ultrasonic and microwave) maceration methods on some quality parameters of aronia juice were investigated. Microwave maceration significantly impacted the soluble solids content of the analysed juices and resulted in noticeably darker juice samples compared to the controls, with lower /lightness (20.

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The brown marmorated stink bug (BMSB; Stål.) is a highly destructive and polyphagous invasive pest that poses a serious threat to more than a hundred reported host plants. In the current study, the metabolic response of peach fruit of two cultivars-'Maria Marta' and 'Redhaven'-to BMSB infestation was studied using high-performance liquid chromatography (HPLC) and mass spectrometry (MS).

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This study aimed to determine the content and composition of bioactive compounds in autochthonous rose hips (, , and ) and to compare them with the content of bioactive compounds in some cultivars ('Harstad', 'Bourgogne', 'Mount Everest', 'Poppius', 'Fruhlingsduft', 'Single Cherry', 'Fruhlingsmorgen', 'Violacea', and 'Splendens') derived from these main species. Due to insufficient information on how bioactive compound content changes when crossing roses, this study also sought to ascertain whether modern rose hip cultivars are still a sufficiently rich source of bioactive compounds and could, therefore, be potentially used as a functional food. All material was collected in the Arboretum Volčji Potok (Slovenia).

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Mulberries are the "essence of the past", the so-called Proust effect, for the inhabitants of the sericultural regions who enthusiastically remember feeding silkworms with mulberry leaves and picking the different coloured fruits that were their favourite sweets in childhood. To determine the chemistry behind the colour and taste of mulberry soroses, the main metabolites of the local and introduced varieties were studied. The soroses were classified into five different colour types and the size parameters were determined.

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Our research aimed to investigate the primary and secondary metabolites of rosehips and petals of in comparison with . was chosen because it is still unexplored in terms of various bioactive substances and is strongly present in Slovenia. Given that roses are generally very variable and unstudied, our research will contribute to greater transparency and knowledge of the bioactive composition of rosehips and petals.

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The present study deals with the comparison of traditional fruit processing methods on medlar fruits and their effects on sugar content, organic acids, and phenolic composition in the medlar fruit variety 'Domača nešplja'. The study aimed to analyze which processing methods can be used to make technologically mature medlar fruits that are not yet suitable for consumption edible and to maintain their good chemical quality. The two major sugars in medlars are fructose (59.

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Black locust ( L.), an invasive tree in Europe, commonly known for its negative impact on biodiversity, is a rich source of phenolic compounds recognized in traditional medicine. Since the metabolite profile depends on the environment and climate, this study aimed to provide the first LC-MS phytochemical screening of the black locust from the Istria region (Croatia).

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Black fruits, especially blackberries and black currants, are highly appreciated by consumers due to their nutraceutical properties, which have reported health benefits. This study aimed to assess the fruit quality of the blackberry (cv. 'Čačanska Bestrna') and black currant (cv.

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The genus is very extensive and variable, so it remains very unpredictable and uninvestigated. This also holds true for values of secondary metabolites in rose hips, which are important for several purposes (human diet, protection of plants against pests, etc.).

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The effects of salicylic acid (SA) and one of its better-known derivatives-methyl salicylic acid (MeSA)-on the infection of apple fruits with the fungus , which causes brown rot, were investigated. Since research to date has focused on preventive effects, we also focused on the curative use of SA and MeSA. Curative use of SA and MeSA slowed the progression of the infection.

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In the present study, the partial substitution of common white wheat flour for a bread recipe with variously bioprocessed wholegrain spelt was investigated. The addition of 1% and pasteurised 5% "germinated + enzymatic treated" spelt flour to wheat flour significantly improved the specific volume of the bread, but their texture profile analysis and sensory evaluation were not satisfactory. A higher percentage of added bioprocessed spelt flour darkened the colour of the bread.

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The aim of the study was to determine whether the partial replacement of wheat flour with bioprocessed spelt flour contributes to a higher bioaccessibility of the antioxidants in bread. The results showed that the type and amount of bioprocessed spelt flour in a bread recipe has a major impact on the extractable and bound TPC, the content of individual phenolics, their antioxidant activity, and their bioaccessibility as determined by in vitro digestion. Extractable -coumaric and -ferulic acids in breads decreased after digestion, while extractable -ferulic and -hydroxybenzoic acids increased.

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The genus is characterized by great variability and, consequently, they easily hybridize. The petals of , and their hybrid × , collected in western Slovenia, were included in the research. We performed morphometric analysis using keys to determine roses and genetic analysis to determine the genome size.

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The content of sugars, organic acids, phenolic compounds and selected enzyme activities in the anthocyanin pathway were analyzed in NIGRA ( var. -black fruits) and VIRIDIS ( var. -green fruits) fruits over four stages of ripening.

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The influence of three cultivars ('Carmen', 'Kordia' and 'Regina') grafted on six rootstocks (Mahaleb, 'Colt', 'Oblacinska', 'M × M 14', 'Gisela 5' and 'Gisela 6') on the phenolic profile of sweet cherry fruits was studied during a two-year period. All the individual phenolic compounds were detected using high-pressure liquid chromatography with diode-array detection coupled with mass spectrometry (HPLC-DAD-MSn). In all the examined samples, 54 compounds were identified and divided into five phenolic classes: anthocyanins (4 compounds), flavonols (7), flavanols (11), flavanones (4), and hydroxycinnamic acids (28).

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We performed a detailed HPLC-MSn analysis of the phenolic compounds from the extracts of two invasive alien plant species (IAPS): Japanese knotweed ( (Houtt.) Ronse Decr.) and American pokeweed ( L.

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Different climatic conditions are known to affect the synthesis of primary and secondary metabolites. Therefore, the phenolic contents in new growing areas could affect the quality and flavor of hazelnuts. The aim of this study was to determine the variability of the phenolic contents of the kernels in different commercial hazelnut cultivars depending on their growing area.

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The goal of this research was to evaluate the impact of different bioprocessing techniques on improved bioaccessibility of phenolics from spelt seeds. Despite the negative influence of gastrointestinal digestion, fermentation of germinated seeds significantly increased the bioaccessibility of total phenolics and their antioxidant activity compared to digested raw seeds. Enzymatic treated fermented seeds showed the highest relative bioaccessibility of -coumaric and -ferulic acids, while their absolute contents were significantly higher in "germinated + fermented" seeds.

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Lactic acid, alcoholic, combined and spontaneous fermentation of raw, germinated and enzymatic-treated spelt seeds significantly improved the content of extractable and bound phenolics and considerably increased the extractable:bound ratio, and therefore positively affected the accessibility of the spelt antioxidants. The highest extractable and bound individual phenolic contents and in vitro antioxidant activities of extracts were obtained following fermentation of germinated spelt seeds with Saccharomyces cerevisiae, while for enzymatic-treated seeds, Lactobacillus plantarum (alone or with S. cerevisiae) was the most effective.

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Invasive plants' phytochemicals are important for their invasiveness, enabling them to spread in new environments. However, these chemicals could offer many pharmaceutical compounds or active ingredients for herbal preparations. This study provides the first LC-MS phytochemical screening of six invasive alien plant species (IAPS) in the Istria region (Croatia): , , , , , and .

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The aim of this work was to assess the biopotential of the young inflorescence tissues of , and in order to evaluate the possibility of their application in the food industry, and to provide a polyphenolic fingerprint for their quality control. The contents of different bioactive compounds and their antioxidant capacities were spectrophotometrically measured, the main phenolic compounds were identified and quantified using LC-DAD-MS, the antidiabetic potential was determined using α-amylase and α-glucosidase inhibition assays, the anti-inflammatory potential was determined using a 5-lipoxygenase inhibition assay, and the cytotoxicity was determined by MTT assay. Using one-way ANOVA, principal component analysis, hierarchical clustering and Pearson's correlation coefficient, the relations between the samples, and between the samples and the measured parameters, were revealed.

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Effects of spraying over apple trees (; '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.

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We investigated how the quality of blackberry fruit changes during the ripening period. Since it is difficult to predict picking dates for blackberries, we were interested in how the quality of fully ripe fruit changed depending on the sampling date (from 28 July to 1 September). Blackberries (at full ripeness) were sampled at six weekly intervals and the contents of sugars, vitamin C, organic acids and phenolic components were analysed by high performance liquid chromatography combined with mass spectrometry.

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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.

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