Characterization of Proteins Extracted from Ulva sp., Padina sp., and Laurencia sp. Macroalgae Using Green Technology: Effect of In Vitro Digestion on Antioxidant and ACE-I Inhibitory Activity

Eda Şensu; Eda Nur Ayar; Emine Şükran Okudan; Beraat Özçelik; Aysun Yücetepe

doi:10.1021/acsomega.3c05041

Characterization of Proteins Extracted from Ulva sp., Padina sp., and Laurencia sp. Macroalgae Using Green Technology: Effect of In Vitro Digestion on Antioxidant and ACE-I Inhibitory Activity

ACS Omega. 2023 Dec 14;8(51):48689-48703. doi: 10.1021/acsomega.3c05041. eCollection 2023 Dec 26.

Authors

Eda Şensu^{1

2}, Eda Nur Ayar¹, Emine Şükran Okudan³, Beraat Özçelik^{1

4}, Aysun Yücetepe⁵

Affiliations

¹ Department of Food Engineering, Faculty of Chemical and Metallurgical Engineering, Istanbul Technical University, Maslak TR-34469, Istanbul, Turkey.
² Department of Food Technology, Istanbul Gelisim Higher Vocational School, Istanbul Gelisim University, Avcılar, Istanbul 34310, Turkey.
³ Faculty of Fisheries, Akdeniz University, Dumlupınar, 07058 Antalya, Turkey.
⁴ BIOACTIVE Research & Innovation Food Manufac. Indust. Trade Ltd., Katar Street, Teknokent ARI-3, B110, Sarıyer 34467, Istanbul, Turkey.
⁵ Department of Food Engineering, Faculty of Engineering, Aksaray University, TR-68100 Aksaray, Turkey.

Abstract

Macroalgal proteins were extracted from Ulva rigida (URPE) (green), Padina pavonica (PPPE) (brown), and Laurencia obtusa (LOPE) (red) using ultrasound-assisted enzymatic extraction, which is one of the green extraction technologies. Techno-functional, characteristic, and digestibility properties, and biological activities including antioxidant (AOA) and angiotensin-I converting enzyme (ACE-I) inhibitory activities were also investigated. According to the results, the extraction yield (EY) (94.74%) was detected in the extraction of L. obtusa, followed by U. rigida and P. pavonica. PPPE showed the highest ACE-I inhibitory activity before in vitro digestion. In contrast to PPPE, LOPE (20.90 ± 0.00%) and URPE (20.20 ± 0.00%) showed higher ACE-I inhibitory activity after in vitro digestion. The highest total phenolic content (TPC) (77.86 ± 1.00 mg GAE/g) was determined in LOPE. On the other hand, the highest AOA_CUPRAC (74.69 ± 1.78 mg TE/g) and AOA_ABTS (251.29 ± 5.0 mg TE/g) were detected in PPPE. After in vitro digestion, LOPE had the highest TPC (22.11 ± 2.18 mg GAE/g), AOA_CUPRAC (8.41 ± 0.06 mg TE/g), and AOA_ABTS (88.32 ± 0.65 mg TE/g) (p < 0.05). In vitro protein digestibility of three macroalgal protein extracts ranged from 84.35 ± 2.01% to 94.09 ± 0.00% (p < 0.05). Three macroalgae showed high oil holding capacity (OHC), especially PPPE (410.13 ± 16.37%) (p < 0.05), but they showed minimum foaming and emulsifying properties. The quality of the extracted macroalgal proteins was assessed using FTIR, SDS-PAGE, and DSC analyses. According to our findings, the method applied for macroalgal protein extraction could have a potential the promise of ultrasonication application as an environmentally friendly technology for food industry. Moreover, URPE, PPPE, and LOPE from sustainable sources may be attractive in terms of nourishment for people because of their digestibility, antioxidant properties, and ACE-I inhibitory activities.