Search

Ispitan je utjecaj djelomične hidrolize pomoću tripsina na fizikalno-kemijska i antioksidativna svojstva izolata proteina heljde, dobivenih iz netretiranih heljdinih mekinja ili ekstrakcijom pomoću 2-propanola. Utvrđeno je da se uklanjanjem fenola znatno poboljšala hidroliza izolata, pri čemu se smanjila količina ukupnih i vezanih polifenola, a povećao udjel slobodnih polifenola. Hidroliza globulina bila je puno brža od hidrolize albumina, koja je poboljšana uklanjanjem polifenola. Modificirani izolati s većim udjelom polifenola imali su bolju sposobnost uklanjanja DPPH radikala i reducirajuću snagu, ali slabiju sposobnost keliranja željeza od izolata s manjim udjelom polifenola. Stoga je zaključeno da je djelomična hidroliza prikladan postupak modifikacije proteina heljde., Effects of limited hydrolysis with trypsin on the physicochemical and antioxidant properties of buckwheat protein isolates (BPIs) obtained with untreated and 2-propanol-extracted meal have been investigated and compared. The dephenolization treatment significantly improved the hydrolysis of BPI, which resulted in the gradual decrease in total and protein-bound polyphenolic content, but an increase in the free polyphenolic content. The hydrolysis of globulins was much easier than that of the albumins. The removal of polyphenols improved the hydrolysis of the albumin fraction. The modified BPIs with high polyphenolic content exhibited much higher DPPH radical scavenging activity and reducing power, but poorer ferrous ion chelating ability than those with low polyphenolic content. These results suggest that the limited hydrolysis is suitable for modification of the properties of buckwheat proteins.

Hemp protein hydrolysates with various yields of trichloroacetic acid (TCA)-soluble peptides (Ysp) and surface hydrophobicity (Ho) were obtained by Neutrase® hydrolysis from hemp protein isolate (HPI). The peptide profiles, amino acid composition and antioxidant activities (DPPH radical scavenging ability, reducing power and Fe2+ chelating ability) of the hydrolysates, obtained at 60–240 min, were evaluated. Higher DPPH radical scavenging (IC50, 2.3–2.4 mg/mL) and Fe2+ chelating (IC50, 1.7–1.8 mg/mL) abilities were observed for the hydrolysates with Ysp in the range of 28–30 and 18–28 %, respectively, while the high reducing power was only observed for the hydrolysate with Ysp of 18 %. The DPPH radical scavenging and Fe2+ chelating abilities were closely correlated with the peptide profiles and Ho of the hydrolysates. The peptide profiles of the hydrolysates with higher hydrophobic amino acids exhibited higher DPPH radical scavenging and Fe2+ chelating abilities., Hidrolizom izolata proteina pomoću enzima Neutrase® dobiveni su hidrolizati proteina konoplje s različitim prinosom peptida topljivih u trikloroctenoj kiselini (Ysp) i hidrofobnošću površine (Ho). Ispitan je peptidni profil, sastav aminokiselina i antioksidativna aktivnost (sposobnost uklanjanja DPPH radikala, reducirajuća snaga i sposobnost stvaranja helata Fe2+) hidrolizata dobivenih nakon 60-240 min. Uočena je veća sposobnost hidrolizata s Ysp=28-30 % da uklone DPPH radikale (IC50; 2,3-2,4 mg/mL), te veća mogućnost stvaranja helata Fe2+ s hidrolizatima vrijednosti Ysp=18-28 % (IC50; 1,7-1,8 mg/mL). Velika je reducirajuća snaga samo u hidrolizata s Ysp=18 %. Sposobnost uklanjanja DPPH radikala i stvaranja helata Fe2+ povezana je s peptidnim profilom i hidrofobnošću površine hidrolizata (Ho). Hidrolizati s većim udjelom hidrofobnih aminokiselina pokazali su bolju sposobnost uklanjanja DPPH radikala i stvaranja helata Fe2.