Ultrasonic-Assisted Extraction and Antioxidant Potential of Valuable Protein from Ulva rigida Macroalgae

Abstract

Ulva green macroalgae or sea lettuce are rich sources of protein with nutritional benefits that promote health as a future plant-based functional ingredient in the food industry. Alkaline pretreatment improved ultrasonic-assisted protein extraction from Ulva rigida biomass. Parameters affecting ultrasonic-assisted extraction of protein were type of solvent, biomass-solvent ratio, biomass preparation and extraction cycle. In vitro digestibility was evaluated from oven- and freeze-dried biomass. Results showed highest concentration and extraction yield of protein from U. rigida using alkaline rather than acid and distilled water. A high biomass–solvent ratio at 1:10 or 0.1 g mL−1 increased protein extraction. Higher alkaline concentration increased protein extraction. Highest protein extractability was 8.5% dry matter from freeze-dried U. rigida biomass, with highest protein extraction and antioxidant activity from extraction of U. rigida macroalgae at high alkaline concentrations. U. rigida macroalgae oven-dried biomass presented suitable human digestibility. Efficient pretreatment of U. rigida maximized protein hydrolysate and bioactive peptide production for wide-ranging applications.

A Fully Integrated Biorefinery Process for the Valorization of Ulva fasciata into Different Green and Sustainable Value-Added Products

“…Ulva fasciata yielded approximately 13.37% crude protein. That is comparable with the previously reported extracted protein yields from Ulva ohnoi [19], Ulva species [44], but higher than that reported for U. rigida [38] which recorded 14.83%, 13.3-15.9%, and 8.5%, respectively.…”

“…All the listed data in Tables 1-5 are comparable to those recorded for different Ulva species [34][35][36][37][38][39][40][41][42][43][44][45]. The protein content (Table 1) is comparable to that reported by Labib and Hosny [46] for Ulva fasciata which recorded 11.68-13.43%, but better than that reported for Ulva lactuca, which recorded 7.16% [12].…”

“…Peak identification was accomplished by comparing mass spectra to the mass spectral library of the National Institute of Standards and Technology (NIST) 2011 (https://www.nist.gov). Using the Bradford method and bovine serum albumin (BSA) as the reference standard, protein concentration was measured [38]. The extracted value-added products have been characterized by Fourier transform infrared (FTIR; Perkin Elmer Spectrum One, Waltham, MA, USA), applying the KBr disc method, and the spectra were scanned in the range of 400-4000 cm −1 with 4 cm −1 and 16 cm/min scan resolution and rate, respectively.…”

Optimization of ultrasound-assisted cellulase degradation method on the extraction of mulberry leaf protein and its effect on the functional characteristics

“…Also, if the ultrasound temperature was too high, it would cause protein denaturation, damage the spatial structure, and decrease the solubility of protein molecules due to mutual binding. At the same time, too high extraction temperature would also reduce the cavitation effect of ultrasound, which was not conducive to protein dissolution [29] . As the ultrasound temperature went up, the PDA of mulberry leaf reached its highest at 35 °C with the PDA value of 8.97 mg/mL and showed a decreasing trend afterwards.…”

Anti-hyperuricemia bioactive peptides: a review on obtaining, activity, and mechanism of action

“…The biological efficacy of peptides various considerably based on amino acid composition, sequence, and molecular weight. 12,16,[19][20][21] In this article, we review bioactive peptides that can alleviate HUA and their mechanisms of treating HUA. We aim to enhance understanding of the application of bioactive peptides in HUA and to provide a theoretical basis for the future development of functional foods or drugs for alleviating HUA.…”