Aleksandra Purkiewicz

Mrs. Aleksandra Purkiewicz

Department of Commodity Science and Food Analysis, Faculty of Food Science, University of Warmia and Mazury in Olsztyn
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 April 2025 in Nutrients
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Journal Article
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APAleksandra Purkiewicz
Aleksandra Purkiewicz
KRKamila Julia Regin
Kamila Julia Regin
WMWajeeha Mumtaz
Wajeeha Mumtaz
RPRenata Pietrzak-Fiećko
Renata Pietrzak-Fiećko
Breastfeeding is recognized as the gold standard in infant nutrition, providing necessary nutrients for optimal growth and development. Beyond its nutritional function, breastfeeding has numerous benefits for both mother and child. This literature review examines the effects of breastfeeding on the development of the nervous and immune systems, its influence on cognitive development, and the impact of stress on lactation. In addition, it explores the emotional effects of breastfeeding on mothers, the challenges associated with exclusive breastfeeding, and the process of weaning along with its implications for both mother and infant. It is indicated that stress significantly affects lactation regulation, with elevated cortisol levels potentially disrupting hormonal balance. Furthermore, the essential roles of oxytocin, sialic acid, and docosahexaenoic acid in infant brain development and cognitive functions are highlighted. Breastfeeding is associated with the regulation of the baby’s sleep through the effects of tryptophan, serotonin, and melatonin, which at the same time provide the baby with a sense of security with the mother. It is indicated that women who breastfeed are less likely to suffer from mental health problems and are at a lower risk of hypertension, diabetes, and cardiovascular disease. The weaning process is often a difficult time for mother and child; thus, it should be introduced gradually to minimize stress, anxiety, and potential mood disturbances in the mother.

11 December 2020 in Plants
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APAleksandra Purkiewicz
Aleksandra Purkiewicz
JCJoanna Ciborska
Joanna Ciborska
Małgorzata TańskaMałgorzata Tańska
Małgorzata Tańska
ANAgnieszka Narwojsz
Agnieszka Narwojsz
Małgorzata StarowiczMałgorzata Starowicz
Małgorzata Starowicz
TSTomasz Sawicki
Tomasz Sawicki
The study assesses the antioxidant activity (AA), carotenoid profile and total phenolic content (TPC) of carrot juices obtained from three different varieties (black, orange and yellow) and prepared using high- (HSJ) and low-speed juicer (LSJ). The AA assessment was carried out using four assays (DPPH, ABTS, PCL ACW and PCL ACL). The content of carotenoids was conducted by high performance liquid chromatography equipped with a diode array detector (HPLC-DAD) method, while the total phenolic content by the spectrophotometric method. It was shown that orange carrot juices contain more carotenoids than yellow and black carrot juices, approximately ten and three times more, respectively. The total carotenoid content in orange carrot juice made by the HSJ was higher (by over 11%) compared to juice prepared by the LSJ. The highest total phenolic content was noticed in black carrot juices, while the lowest in orange carrot juices. In black carrot juices, a higher range of TPC was found in juices made by HSJ, while in the case of the orange and yellow carrots, the highest content of TPC was detected in juices prepared by the LSJ. AA of the juices was highly dependent on the carrot variety, juice extraction method. The most assays confirmed the highest AA values in black carrot juices. Furthermore, it was shown that the HSJ method is more preferred to obtain orange and yellow carrot juices with higher antioxidant properties, while the LSJ method is more suitable for black carrot juice extraction.

Joanna ŁuczyńskaJoanna Łuczyńska
Joanna Łuczyńska
RPRenata Pietrzak-Fiećko
Renata Pietrzak-Fiećko
APAleksandra Purkiewicz
Aleksandra Purkiewicz
MŁMarek Jan Łuczyński
Marek Jan Łuczyński
The aim of this study was to estimate the fish quality in terms of the Cu, Fe, Mn and Zn contents. The research material was the muscle tissue of the fish crucian carp (Carassius carassius Linnaeus, 1758), flounder (Platichthys flesus Linnaeus, 1758), Gilthead seabream (Sparus aurata Linnaeus, 1758), mackerel (Scomber scombrus Linnaeus, 1758), Blue grenadier (Macruronus novaezelandiae Hector, 1871), rainbow trout (Oncorhynchus mykiss Walbaum, 1792), tench (Tinca tinca Linnaeus, 1758), tilapia (Oreochromis niloticus Linnaeus, 1758), Walleye pollock (Gadus chalcogrammus Pallas, 1814) and perch (Perca fluviatilis Linnaeus, 1758.). Heavy metals were determined with the atomic absorption spectrometry method (AAS). Significantly high concentrations of zinc (19.52 mg/kg wet weight), copper (0.77 mg/kg) and iron (6.95 mg/kg) were found in the muscles of crucian carp (p < 0.05) compared to the other fish studied, whereas Walleye pollock had a higher content of manganese (0.266 mg/kg) (p < 0.05). All studied fish species do not pose a threat to humans from these four metals. This was indicated by quality indexes (THQ and HI) whose values were below one. The values of these metals also did not exceed the maximum allowable concentrations established by the FAO (1983), but monitoring both the aquatic environment and the fish living there is necessary, for example, for the time-changing abiotic and biotic factors that can cause an increase in metals in the organs of fish.

24 May 2021 in Molecules
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APAleksandra Purkiewicz
Aleksandra Purkiewicz
RPRenata Pietrzak-Fiećko
Renata Pietrzak-Fiećko
The study assesses the antioxidant activity, total phenolic content, total flavonoids content and lipophilic pigments (β-carotene, chlorophyll a, chlorophyll b) content in homemade and marketed fruit and vegetable whey beverages and fruit and vegetable mousses. All of the tests were performed using spectrophotometric methods. The highest polyphenol content was found in the homemade green whey beverage W1G (541.95 mg/100 g) and the lowest in the market green whey beverage W2G (46.18 mg/100 g). In the fruit and vegetable mousses under study, the highest content of polyphenolic compounds was determined in the red mousse R3 (76.41 mg/100 g). The highest content of flavonoids was observed in the homemade orange whey beverage W1O (63.06 mg/100 g) and in the green mousse G2 (69.80 mg/100 g). The values of the antioxidant activity of whey beverages and mousses varied depending on the composition. The highest content of β-carotene was identified in homemade orange whey beverage (4.36 mg/100 g) and in orange mousses (in range 1.10–2.24 mg/100 g), while chlorophylls a and b—in homemade green whey beverage W1G (3.00 mg/100 g and 1.31 mg/100 g respectively) and in green mousses (chlorophyll a in range 0.54 to 1.42 mg/100 g and chlorophyll b in range 0.13 to 0.32 mg/100 g).

6 October 2023 in Foods
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APAleksandra Purkiewicz
Aleksandra Purkiewicz
MSMałgorzata Stasiewicz
Małgorzata Stasiewicz
JNJacek J. Nowakowski
Jacek J. Nowakowski
RPRenata Pietrzak-Fiećko
Renata Pietrzak-Fiećko
(1) Background: This study investigated the effect of the lactation period and the type of infant formula on the content of amino acids and selected minerals in an infant’s food; (2) Methods: The study material consisted of breast milk (colostrum, n = 38; transitional milk, mature milk, n = 38) and three types of infant formulas (for first and follow-on feeding). Amino acid content was determined using an automatic amino acid analyzer, while minerals were determined by the atomic absorption spectrometry (AAS) technique; (3) Results: Breast milk and infant formulas contained a full range of essential amino acids. In most cases, the content of individual amino acids and minerals decreased with increasing lactation. In infant formulas, there were higher contents of phenylalanine, glutamic acid, proline, serine, and tyrosine in follow-on milk (p < 0.05). The EAA/TAA ratio in breast milk and infant formulas was similar, but the milk differed in their qualitative composition. Infant formulas contained levels of individual minerals that were several times higher—especially Mg, Ca, Mn, and Fe.; (4) Conclusions: Colostrum is more concentrated, and the level of amino acids and minerals is higher in it; as the milk matures, it decreases. In most cases, the content of individual amino acids and minerals is higher in infant formulas than in human milk, which is established through strict Codex Alimentarius procedures to ensure the proper development of infants.

25 May 2022 in Nutrients
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Journal Article
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APAleksandra Purkiewicz
Aleksandra Purkiewicz
RPRenata Pietrzak-Fiećko
Renata Pietrzak-Fiećko
FSFritz Sörgel
Fritz Sörgel
MKMartina Kinzig
Martina Kinzig
This study aimed to assess the content of caffeine and its metabolites—paraxanthine, theophylline, and theobromine—in breast milk according to selected factors. Samples of human milk were collected from 100 women living in the east–northeast region of Poland. Information on the consumption of beverages and foods containing caffeine was collected using a 3 day food record. The determination of caffeine and its metabolite content was performed using liquid chromatography–mass spectrometry (LC–MS/MS). This study research showed that more caffeine was found in the milk of women living in cities, with secondary education, aged 34–43, and also in milk from the 3rd and 4th lactation periods (p ≤ 0.05). Factors such as place of residence, level of education, age, and stage of lactation influenced the nutritional choices of breastfeeding women, which had an impact on the level of caffeine and its metabolites in breast milk. A positive correlation was found between the consumption of caffeine with food and drinks and its level in human milk.