Witold Pietrzak

Dr. Witold Pietrzak


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

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

Representative Publications

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2 July 2020 in Molecules
Verified
Journal Article
Open access
PDF file
AGAlan Gasiński
Alan Gasiński
JKJoanna Kawa-Rygielska
Joanna Kawa-Rygielska
Antoni Jacek SzumnyAntoni Jacek Szumny
Antoni Jacek Szumny
ACAnna Czubaszek
Anna Czubaszek
JPJustyna Paszkot
Justyna Paszkot
WPWitold Pietrzak
Witold Pietrzak
This study was performed to determine the possibility of using mango fruit (Mangifera indica) in brewing technology. The aim of using the SPME-HS-GC-MS technique was to assess what changes occurred in the volatile composition of mango beers brewed in this study. Mango fruit was added to the beer in five different forms to ascertain what kind of preparation should be used to improve beer aroma. Analysis of the volatile components in mango beer showed that beer without mango addition was characterized by the lowest content of volatile compounds (1787.84 µg/100 mL). The addition of mango fruit increased the concentration of compounds, such as α-pinene, β-myrcene, terpinolene, α-terpineol, cis-β-ocimene, caryophyllene, and humulene, in beer. Beer prepared with mango pulp addition was characterized by the highest concentration of volatile components from mango beers (2112.15 µg/100 mL). Furthermore, beers with mango addition were characterized by a higher polyphenol content (up to 44% higher than control beer) and antioxidant activity than control beer and were evaluated by a trained panel as having a better taste and aroma than beer without fruit addition.


18 September 2020 in Sustainability
Verified
Journal Article
Open access
PDF file
KDKatarzyna Drzymała
Katarzyna Drzymała
AMAleksandra M. Mirończuk
Aleksandra M. Mirończuk
WPWitold Pietrzak
Witold Pietrzak
ADAdam Dobrowolski
Adam Dobrowolski
The aim of this study was to test rye straw, rye bran and oat bran hydrolysates as substrates for growth of the yeast Yarrowia lipolytica, a microorganism known to have large biotechnological potential. First, after the combined process of acid-enzymatic hydrolysis, the concentration and composition of fermentable monosaccharides in the obtained hydrolysates were analyzed. Glucose was the main sugar, followed by xylose and arabinose. Rye bran hydrolysate had the highest sugar content—80.8 g/L. The results showed that this yeast was able to grow on low-cost medium and produce biomass that could be used as a feed in the form of single cell protein. The biomass of yeast grown in oat bran hydrolysate was over 9 g/L after 120 h, with the biomass total yield and total productivity values of 0.141 g/g and 0.078 g/h, respectively. The protein contents in yeast biomass were in the range of 30.5–44.5% of dry weight. Results obtained from Y. lipolytica cultivated in rye bran showed high content of exogenous amino acid (leucine 3.38 g, lysine 2.93 g, threonine 2.31 g/100 g of dry mass) and spectrum of unsaturated fatty acid with predominantly oleic acid—59.28%. In conclusion, these results demonstrate that lignocellulosic agricultural waste, after hydrolysis, could be efficiently converted to feed-related yeast biomass.


21 May 2016 in International Journal of Food Science and Technology
Verified
Journal Article
Closed access
PDF file
MKMałgorzata Kapelko-Żeberska
Małgorzata Kapelko-Żeberska
MAMałgorzata
Małgorzata
TZTomasz Zięba
Tomasz Zięba
WPWitold Pietrzak
Witold Pietrzak
AGArtur Gryszkin
Artur Gryszkin

1 April 2013 in Bioresource Technology
Verified
Journal Article
Closed access
JKJoanna Kawa-Rygielska
Joanna Kawa-Rygielska
WPWitold Pietrzak
Witold Pietrzak
PRPiotr Regiec
Piotr Regiec
PSPiotr Stencel
Piotr Stencel