Renata Pietrzak-Fiećko

Dr. Renata Pietrzak-Fiećko

Department of Commodities and Food Analysis, Faculty of Food Sciences, University of Warmia and Mazury in Olsztyn, Cieszyński 1 Sq, 10719 Olsztyn, Poland
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Research Focus & Metrics

Academic Career Length

57Years (1970-Present)

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

Representative Publications

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14 May 2020 in Nutrients
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RPRenata Pietrzak-Fiećko
Renata Pietrzak-Fiećko
ASAnna Malwina Kamelska- Sadowska
Anna Malwina Kamelska- Sadowska
(1) Background: The variation in the concentration of different components found in milk depends on mammalian species, genetic, physiological, nutritional factors, and environmental conditions. Here, we analyse, for the first time, the content of different components (cholesterol concentration and fatty acids composition as well as the overall fat and mineral content determined using the same analytical methods) in milk of different mammal species. (2) Methods: The samples (n = 52) of human, cow, sheep, goat and mare milk were analyzed in triplicate for: cholesterol concentration, fatty acids profile and fat and mineral content (calcium, magnesium, sodium, potassium, iron, zinc). (3) Results: The highest fat content was reported in sheep milk (7.10 ± 3.21 g/dL). The highest cholesterol concentration was observed in bovine (20.58 ± 4.21 mg/dL) and sheep milk (17.07 ± 1.18 mg/dL). The saturated fatty acids were the lowest in human milk (46.60 ± 7.88% of total fatty acids). Goat milk had the highest zinc (0.69 ± 0.17 mg/dL), magnesium (17.30 ± 2.70 mg/dL) and potassium (183.60 ± 17.20 mg/dL) content. Sheep milk had the highest sodium (52.10 ± 3.20 mg/dL) and calcium (181.70 ± 17.20 mg/dL) concentration values. (4) Conclusions: The differences in nutritional value of milk could be perceived as a milk profile marker, helping to choose the best food for human nutrition.

11 April 2025 in Nutrients
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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.

31 December 2017 in Czech Journal of Animal Science
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EJEWA JASTRZĘBSKA
EWA JASTRZĘBSKA
EWEwa Wadas
Ewa Wadas
TDTomasz Daszkiewicz
Tomasz Daszkiewicz
RPRenata Pietrzak-Fiećko
Renata Pietrzak-Fiećko
» Articles | Agricultural Journals


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).