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1

Antioxidant potential and phytochemical content of selected fruits and vegetables consumed in Cyprus

Georgiadou E. C., Goulas V., Majak I., Ioannou A., Leszczyńska J., Fotopoulos V.

Biotechnology and Food Science

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2018

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Vol. 82, nr 1

3--14

EN

Consuming a diet high in fruits and vegetables can lower the risk of developing numerous chronic diseases, including cancer and cardiovascular disease, due to the presence of multiple antioxidants. Horticultural produce consumed in Cyprus include a large variety of fruits and vegetables, most of which are common components of a Mediterranean-style diet due to the island’s localization. The aim of the present study was to evaluate the antioxidant composition and activity of the edible portion of ten fruits and ten vegetables commonly consumed in Cyprus. Total phenolics, total anthocyanins, ascorbic acid and carotenoids contents were determined, while the in vitro antioxidant activity was evaluated by three assays. Antioxidant activity showed great variation, with the highest values found in green olives, capers and red chili peppers and in correlation with total phenolic content. Ascorbic acid was detected in large quantities in parsley, coriander, red guavas and red chili peppers, while red chili peppers, capers and coriander had high levels of carotenoids. Furthermore, sweet cherries, red grapes, and red apples contained significant amounts of anthocyanins. Statistical analysis revealed that phenolic compounds are the most potent antioxidants in fruit and vegetables, while total anthocyanins had a weak contribution to their antioxidant activity. The present study could be a guide for Cypriot as well as Mediterranean diet health-conscious consumers to select specific fruits and vegetables as dietary components. To the best of our knowledge, this is the first study thoroughly describing the antioxidant composition and activity of a wide array of important Cypriot horticultural products.

2

5-hydroxymethylfurfural content in selected gluten- and gluten-free cereal food products

Mańkowska D., Majak I., Bartos A., Słowianek M., Łącka A., Leszczyńska J.

Biotechnology and Food Science

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2017

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Vol. 81, nr 1

11--21

EN

5-Hydroxymethylfurfural (HMF) was determined with HPLC method in forty one food samples, including gluten-free, breakfast cereals and bakery products. The highest concentration of HMF was found in wheat bread with cranberries (210 mg kg-1) and in breakfast cereals – honey wheat loops (85.099 mg kg-1). In contrast, wholegrain oatmeal and gluten-free sponge cakes had the lowest HMF level of all tested samples, below the detection limit and 0.485 mg kg-1, respectively. In most cases, lack of gluten coincided with the lowest HMF content readings (average 8.488 mg kg-1). The impact of the type of sugar, especially glucose, on the HMF concentration in food is apparent. Sweetened breakfast cereals, with the average content of HMF at 25.55 mg kg-1, took lead over dietary products (8.488 mg kg-1) and bakery products (18.395 mg kg-1), with the exception for wheat bread with cranberries. These cereals contained glucose or glucose-fructose syrup.

3

Quantum dots and their immunochemical applications

Malik A., Kurczewski M., Majak I.

Biotechnology and Food Science

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2016

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Vol. 80, nr 2

137--149

EN

Quantum dots (QDs) are nanometre size semiconductor crystals which possess unique physical and chemical properties. In recent years they were widely used as signal enhancers in biological analysis, mainly because of their high quantum yield, photostability and long-lasting photoluminescence. Compared to common organic fluorophores QDs exhibit wider absorption spectra (QDs absorb photons when excitation energy exceeds the bandgap), narrow emission wavelengths and high Stoke’s shift which allow usage of several different-coloured QDs in single multiplex assays. QDs’ synthesis can be conducted by top-down or bottomup approach. Both methods of synthesis may lead to surface imperfections which may negatively affect QDs’ optical properties. To avoid this problem surface passivation is required. The most widely used passivation method is to cover the QD’s core with material having larger band gap (ZnS). QDs can be widely used in different applications due to the ease of surface functionalization by means of organic and inorganic molecules (polymers, dendrimers, proteins, antibodies and etc.) by many different approaches like ligand-exchange, silanization, amphiphilic combination and other mechanisms. Functionalized QDs have been used for various purposes in in-vitro and in-vivo imaging, drug delivery, therapeutics and other. However this review is mainly focused on immunochemical applications of QDs such as immunohistochemistry, FLISA, FRET, immunosensors etc. QD-based immunological assays are being used for detection of pathogens, toxins, proteins, metal ions (Hg2+) and allergens. Based on growing rate of QDs’ applications it can be concluded that in the coming years their number is going to increase.

4

Methods of allergen detection based on DNA analysis

Słowianek M., Majak I.

Biotechnology and Food Science

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2011

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Vol. 75, nr 2

39-44

EN

Many allergens, such as hazelnut, peanut, charlock, celery, sesame, lupine, walnut, almond, macadamia nut, hickory, pistachio, wheat gliadins, may be present in food products, however, undeclared or as unintentional additives. Due to the growing number of allergic reactions, it is crucial to have fast, reliable methods of allergen detection in processed food products. This review summarizes the recent methods of allergen detection in food products based on PCR reactions, namely PCR-ELISA, Real-time PCR, PCR-PNA-HPLC, Duplex PCR and Multiplex Real-time PCR, describing their principles, applications, detection limits, drawbacks and advantages.

5

Immunoreactivity of chemically cross-linked gluten and hydrolysates of wheat flour

Majak I., Leszczyńska J., Łącka A.

Biotechnology and Food Science

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2011

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Vol. 75, nr 2

27-34

EN

The immunoreactivity of gluten and wheat flour proteins crosslinked with chosen chemical reagents was investigated. Native proteins and flour hydrolysates subject to enzymatic proteolysis with collagenase and subtilisin were studied. Determination of immunoreactivity was performed with noncompetitive ELISA method with coeliac patients' sera. The lowest immunoreactivity values were obtained during cross-linking of wheat flour hydrolyzates with polyethyleneimine, below 5% of the values for nonmodified flour.