Volume: 4, 2025
4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland:
ENVIRONMENT – PLANT – ANIMAL – PRODUCT
Abstract number: H002
DOI: https://doi.org/10.24326/ICDSUPL4.H002
Published online: 9 April 2025
ICDSUPL, 4, H002 (2025)
Antioxidant properties of hydrolysates obtained by in vitro digestion of protein isolates from seeds of selected cucurbits
Magdalena Borecka1, Monika Karaś1
1 Department of Biochemistry and Food Chemistry, Faculty of Food Sciences and Biotechnology, University of Life Sciences in Lublin, Skromna 8, 20-704 Lublin, Poland
* Corresponding author: magdalena.borecka@up.lublin.pl
Abstract
Antioxidants play a crucial role in protecting the body from oxidative stress, which can lead to various diseases. Protein hydrolysates, derived from plant seeds, are a promising source of bioactive peptides with antioxidant properties. This study aimed to evaluate the antioxidant activities of hydrolysates obtained through in vitro digestion of protein isolates derived from defatted seeds of selected cucurbit plants, including watermelon (W), pumpkin (Pu), pattypan squash (P), zucchini (Z), pattypan squash with husk (PH), and zucchini with husk (ZH). In vitro gastric and intestinal digestions of protein isolates were conducted based on the INFOGEST protocol. The peptide content in hydrolysates was determined by the TNBS test. The antioxidant properties of the hydrolysates were assessed using the ABTS, DPPH, iron chelation (Fe²⁺), and reducing power assays. The results were expressed as IC50, representing the concentration required to achieve 50% of the antioxidant effect. During simulated digestion, peptides were gradually released. The hydrolysates exhibited varying antioxidant activities. The best results were obtained for the pattypan squash protein seeds (P) hydrolysate, with the lowest IC50 values in both the ABTS (2.29 mg/ml) and DPPH (39.43 mg/ml) assays, indicating superior ability to neutralize free radicals. Hydrolysates from seeds with husk (ZH, PH) demonstrated slightly lower activities in terms of free radical scavenging and iron chelation compared to those without husk (Z, P). Specifically, the iron chelation assays revealed the highest chelation capacity in the hydrolysates of zucchini (Z) and pattypan squash (P) (IC50 values of 1.38 and 1.97 mg/ml, respectively). In contrast, hydrolysates from seeds with husk (ZH, PH) exhibited higher IC50 values (2.26 and 3.31 mg/ml), suggesting a reduced ability to chelate iron. The reducing power assays also showed that the watermelon hydrolysate had significantly higher reducing power than the rest hydrolysates. Proteolysis of proteins during gastrointestinal digestion releases bioactive peptides with potential health benefits. This study demonstrates that hydrolysates of protein derived from cucurbit seeds, particularly from pattypan and zucchini, exhibit significant antioxidant potential, with a strong ability to neutralize free radicals and chelate metal ions.
Keywords: antioxidant activity, protein hydrolysates, cucurbit seeds, in vitro digestion
How to cite
M. Borecka, M. Karaś, 2025. Antioxidant properties of hydrolysates obtained by in vitro digestion of protein isolates from seeds of selected cucurbits. In: 4th International PhD Student’s Conference at the University of Life Sciences in Lublin, Poland: Environment – Plant – Animal – Product. https://doi.org/10.24326/ICDSUPL4.H002