Milica Fotirić Akšić

Analysis and characterisation of phytochemicals in mulberry (Morus alba L.) fruits grown in Vojvodina, North Serbia

In this study, the polyphenolic profile of 11 Morus alba fruits grown in the Vojvodina region was investigated. Ultra high performance liquid chromatography (UHPLC) coupled with Linear Trap Quadrupole and OrbiTrap mass analyzer, and UHPLC coupled with a diode array detector and a triple-quadrupole mass spectrometer were used for the identification and quantification of the polyphenols, respectively. A total of 14 hydroxycinnamic acid esters, 13 flavonol glycosides, and 14 anthocyanins were identified in the extracts with different distributions and contents according to the sampling. The total phenolic content ranged from 43.84 to 326.29 mg GAE/100g frozen fruit. The radical scavenging capacity (50.18-86.79%), metal chelating ability (0.21-8.15%), ferric ion reducing power (0.03-38.45 μM ascorbic acid) and superoxide anion radical scavenging activity (16.53-62.83%) were assessed. The findings indicated that mulberry polyphenolics may act as potent superoxide anion radical scavengers and reducing agents.

Classification and fingerprinting of different berries based on biochemical profiling and antioxidant capacity

O objetivo deste trabalho foi avaliar a composicao bioquimica de seis especies de pequenas frutas dos generos Fragaria, Rubus, Vaccinium e Ribes. As amostras das frutas foram coletadas em triplicata (com 50 frutas cada) de 18 diferentes especies ou cultivares dos generos mencionados, durante tres anos (2008 a 2010). Os teores individuais de acucares, acidos orgânicos, flavonois e acidos fenolicos foram determinados por cromatografia liquida de alta performance (HPLC), e os fenois totais (FT) e a capacidade antioxidante total (CAT), por meio de espectrofotometria. As analises de componente principal (ACP) e de agrupamento hierarquico (AH) foram utilizadas para avaliar as diferencas no perfil bioquimico das frutas. Os maiores teores de compostos bioativos foram encontrados em Ribes nigrum e em Fragaria vesca, Rubus plicatus e Vaccinium myrtillus. ACP e AH foram capazes de discriminar parcialmente as frutas com base em sua composicao bioquimica. Os acucares totais e individuais, a miricetina, o acido elagico, FT e CAT foram os parâmetros que mais impactaram na avaliacao da composicao bioquimica das pequenas frutas. AH fez a separacao de amora-preta, framboesa e mirtilo como grupos isolados, porem a classificacao do morango, da groselha-preta e da groselha-vermelha, em um grupo especifico, nao ocorreu. Ha grande variabilidade entre e dentro dos diferentes tipos de frutas vermelhas. A identificacao de metabolitos das pequenas frutas mostrou perfis bioquimicos unicos e combinacoes especificas de teores de compostos bioativos.

Phenotypic Diversity of Apple (Malus sp.) Germplasm in South Serbia

To determine the overall degree of polymorphism, detect similarities among the accessions and collect highly valued genotypes of native apples, 21 characters of 18 autochthonous apple cultivars were studied for three years. Particular individual accessions were selected from the south region of Serbia according to economically valuable characters and tested in situ. Agronomic evaluation of germplasm accessions revealed considerable diversity among different accessions for all the characters studied. The analysis of variance revealed significant differences among the accessions and among years for some characters as well. Cluster analysis distinguished Malus sp. accessions into three distinct groups. Despite of the significant differences among the accessions, yield and fruit weight were a clear separation between the clusters. Among the germplasm of a small geographic area, it was possible to find the cultivars with valuable morphological traits that could be immediately distributed to the market or employed in breeding programs.

Polyphenolic Profile of Pear Leaves with Different Resistance to Pear Psylla (Cacopsylla pyri)

The European pear psylla, Cacopsylla pyri L. (Hemiptera: Psyllidae), is one of the most serious arthropod pests of pear. Since proper control of this pest is essential, better understanding of the complex plant-pest relationship is mandatory. This research deals with constitutive polyphenolic profiles in leaves of 22 pear cultivars of diverse origin (P. communis, P. pyrifolia, and P. pyrifolia × P. communis) and different resistance to psylla. The study was designed to show which differences in the polyphenolic profile of leaves from resistant and susceptible pear cultivars could be utilized as information in subsequent breeding programs. The results demonstrated that the leaves of Oriental pear cultivars contained much higher amounts of p-hydroxybenzoic acid, ferulic acid, aesculin, and naringin, that, together with detected 3-O-(6″-O-p-coumaroyl)-hexoside, apigenin, apigenin 7-O-rutinoside, and hispidulin, indicated a clear difference between the species and might represent phenolics responsible for psylla resistance.

Influence of frost damage on the sugars and sugar alcohol composition in quince (Cydonia oblonga Mill.) floral nectar

Cold stress adversely affects growth and productivity, and triggers a series of morphological, physiological, biochemical and molecular changes in plants. Since sugars are present in all floral nectars in greater amounts than any other constituent, the aim of this study was to examine how frost exposure changes sugar metabolism and how it affects on the content of sugar components in the nectar of quince. Three quince cultivars (‘Vranjska’, ‘Triumph’ and ‘Leskovačka’) were investigated in this study. The contents of sugars (glucose, fructose, sucrose, trehalose, maltose, isomaltose, rhamnose, arabinose, ribose, melezitose, raffinose, and panose) and sugar alcohols (sorbitol, erythritol, mannitol and galactitol) were analyzed by high performance anion exchange chromatography (HPAEC) with amperometric detection. The results showed that after late spring frosts and irreversible damage of flower parts, the nectar of the three quince cultivars contained elevated levels of fructose, trehalose, arabinose, ribose, rhamnose, raffinose, galactitol and mannitol, indicating an impairment of central carbohydrate metabolism. The ratios between individual sugars, such as the glucose/fructose ratio, were changed in the nectar of damaged flowers in all three quince cultivars. The examined cultivars showed similar sugar response to cold stress. The only exception was ‘Leskovačka’ for the glucose and melezitose pathway, which means that composition of those two sugars changed significantly according to the genotype. The larger are the carbohydrates reserves in different parts of a fruit tree, the higher is the tolerance to any form of frost damage, the results of this study could help in the understanding of how different quince cultivars react to this kind of stress and how they modulate their sugar metabolism.

Chemical profile of major taste- and health-related compounds of Oblačinska sour cherry

BACKGROUND Oblačinska sour cherry, an autochthonous cultivar, is the most planted cultivar in Serbian commercial orchards. Owing to its long cultivation under different agro-ecological conditions, it is a mixture of different clones. To obtain comprehensive information on Oblačinska sour cherry fruit, the total carbohydrate composition, total phenolic content, total anthocyanin content, antioxidant activity and polyphenolic profiles of 39 clones were investigated. RESULTS Fructose was found to be the dominant sugar, followed by glucose, sorbitol and sucrose. Rutin and chlorogenic acid were the most abundant polyphenols. Some clones contained pinobanksin, hesperetin and galangin, which, to best knowledge, is the first time these compounds have been reported in sour cherry fruit. CONCLUSION The data obtained showed huge variation within the germplasm studied, confirming the fact that Oblačinska sour cherry is not a cultivar but a population.

Sugar Profile of Kernels as a Marker of Origin and Ripening Time of Peach (Prunus persicae L.)

Large amounts of fruit seeds, especially peach, are discarded annually in juice or conserve producing industries which is a potential waste of valuable resource and serious disposal problem. Regarding the fact that peach seeds can be obtained as a byproduct from processing companies their exploitation should be greater and, consequently more information of cultivars’ kernels and their composition is required. A total of 25 samples of kernels from various peach germplasm (including commercial cultivars, perspective hybrids and vineyard peach accessions) differing in origin and ripening time were characterized by evaluation of their sugar composition. Twenty characteristic carbohydrates and sugar alcohols were determined and quantified using high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC/PAD). Sucrose, glucose and fructose are the most important sugars in peach kernels similar to other representatives of the Rosaceae family. Also, high amounts of sugars in seeds of promising hybrids implies that through conventional breeding programs peach kernels with high sugar content can be obtained. In addition, by the means of several pattern recognition methods the variables that discriminate peach kernels arising from diverse germplasm and different stage of maturity were identified and successful models for further prediction were developed. Sugars such as ribose, trehalose, arabinose, galactitol, fructose, maltose, sorbitol, sucrose, iso-maltotriose were marked as most important for such discrimination.

Distribution of elements in seeds of some wild and cultivated fruits. Nutrition and authenticity aspects: Distribution of elements in seeds of some wild and cultivated fruits

BACKGROUND The compositional, functional, and nutritional properties of fruits are important for defining their quality. Fruit seeds should be better exploited as they are also considered to be a good source of bioactive components. Twenty macro, micro, and trace elements were identified and quantified in the seeds of 70 genuine wild and cultivated fruit species/cultivars by inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. Sophisticated chemometric techniques were also used to establish criteria for the classification of the analyzed samples. RESULTS Calcium and P were the most abundant elements, followed by K and Na. The content of microelements and trace elements differed among the different cultivars/genotypes. The content of Ba, Pb, and Sr was significantly higher in wild fruits, whereas Fe, Mg, Mn, Ni and Zn content was higher in cultivated fruits. CONCLUSION All of the statistical procedures that were used - Kruskal-Wallis, Mann-Whitney U-test, and principal component analysis (PCA) - confirm a unique set of parameters that could be used as phytochemical biomarkers to differentiate fruit-seed samples belonging to different cultivars/genotypes according to their botanical origin. This kind of investigation may contribute to intercultivar/genetic discrimination and may enhance the possibilities of acquiring a valuable authenticity factor.

Carbon stable isotope composition of modern and archaeological Cornelian cherry fruit stones: a pilot study

ABSTRACT The carbon stable isotope content of Cornelian cherry stones collected from wild tree stands in Serbia, SE Europe, was measured using elemental analyser-isotope ratio mass spectrometry, with the aim of recording natural carbon isotope composition of the fruit stones and its possible variation. The results show a significant variation in the carbon isotope values; we identified several environmental factors that, along with a number of other possible determinants, likely contributed to this variation. The obtained data are compared with the measurement of carbon isotope content of an archaeological specimen of Cornelian cherry stone discovered at the Neolithic site of Vinča (ca. 5600–4500 BC) in Serbia. Notwithstanding the limitedness of the data and the complexity surrounding carbon fractionation and the isotopic variation, it is suggested that the differences/similarities in carbon isotope ratios between modern and archaeological Cornelian cherry stones, when measured for much larger assemblages, could potentially offer a glimpse into growing conditions of Cornelian cherry trees in the past.

Determination of the phenolic profile of peach (Prunus persica L.) kernels using UHPLC–LTQ OrbiTrap MS/MS technique

Recently, search for new natural sources of compounds with health-enhancing properties prompted interest in fruit kernels. This paper aims to assess peach kernels as a source of nutritionally important compounds, such as phenolic compounds. A total of 25 kernels from various peach germplasm differing in origin and ripening time were characterized by their phenolic profiles. Ultra-high-Performance Liquid Chromatography coupled with Linear Trap Quadrupole and OrbiTrap MS/MS hybrid mass spectrometry was used for determination of 76 different organic compounds. The content of identified phenolic compounds indicated peach kernel as reliable source of bioactive substances with prevalent concentrations of catechin and several phenolic acids. Statistical procedures confirm that phenolic compounds could be used as phytochemical biomarkers to differentiate peach kernel samples belonging to different cultivars/genotypes according to their origin and ripening time. The CATPCA confirmed the possibility of application of chemical profiles presented only as categorical variables for classification.