Antimicrobial and Functional Properties of Duckweed (Wolffia globosa) Protein and Peptide Extracts Prepared by Ultrasound-Assisted Extraction

Abstract

Wolffia globosa is an interesting alternative plant-based protein source containing up to 40% protein dry weight. Dried duckweed protein extract (PE) was obtained using ultrasound-assisted extraction (UAE) before isoelectric precipitation (pH 3.5) to yield protein concentrate (PC) and protein solution (PS). The PC was hydrolyzed using Alcalase enzyme to obtain protein concentrate hydrolysate (PCH). Among all fractions, PCH exhibited antimicrobial properties by decreasing populations of Vibrio parahaemolyticus and Candida albicans at 0.43 ± 1.31 log reduction (66.21%) and 3.70 ± 0.11 log reduction (99.98%), respectively. The PE and PS also showed high solubilities at pH 8 of 90.49% and 86.84%, respectively. The PE demonstrated the highest emulsifying capacity (EC) (71.29%) at pH 4, while the highest emulsifying stability (ES) (~98%) was obtained from the PE and PS at pH 6 and pH 2, respectively. The major molecular weights (Mw) of the PE, PC, PCH and PS were observed at 25, 45, 63 and 100 kDa, with a decrease in the Mw of the PCH (<5 kDa). The PCH contained the highest total amino acids, with aspartic acid and glutamic acid being the major components. The results revealed the antimicrobial and functional properties of duckweed protein and hydrolysate for the first time and showed their potential for further development as functional food ingredients.

Comparison of an Artificial Neural Network and a Response Surface Model during the Extraction of Selenium-Containing Protein from Selenium-Enriched Brassica napus L.

“…The extraction solvents were selected by using the method of Duangjarus et al [ 19 ] with slight modifications. An amount of 1g SEP powder was filled into each of five centrifuge tubes before 10 mL of ultra-pure water, NaCl solution (1 mol/L), ethanol solution (75% by volume), alkaline solution (0.1 mol/L NaOH solution), and acid solution (0.1 mol/L HCl solution), respectively, were added into those tubes.…”

Alternative Protein Sources and Novel Foods: Benefits, Food Applications and Safety Issues

“…Most studies also focused on the genus Lemna , although scant information is available on the biological and functional properties of the released peptides. Antimicrobial activity, ACE inhibitory, and DPPH scavenging activities were found for enzymatic hydrolysates obtained by W. globose , Lemna minor , and Chlorella sorokiniana proteins [ 257 , 258 ]. Microalgae peptides that mimic the functions of mediators involved in pathologic processes responsible for vascular damage playing a putative role in the prevention of cardiovascular disease were discussed by Li et al [ 212 ].…”

Plant Protein-Derived Active Peptides: A Comprehensive Review

“…The results showed that ultrasound microwave-assisted enzymatic hydrolysis (ultrasonic frequency of 40 kHz, microwave power of 10–800 W, temperature of 50 °C for 30–240 min) significantly increased the degree of hydrolysis of sweet potato protein hydrolysates and exhibited higher antioxidant activity compared with untreated samples . At present, ultrasound and microwave-assisted methods have also been successfully used to prepare active peptides from plants such as duckweed ( Lemna minor L. ), pineapple byproducts, and black soybeans, which have great application potential. ,, It is worth pointing out that the microwave-assisted method also has widespread application in solid-phase peptide synthesis. , …”

“…111 At present, ultrasound and microwaveassisted methods have also been successfully used to prepare active peptides from plants such as duckweed (Lemna minor L.), pineapple byproducts, and black soybeans, which have great application potential. 14,112,113 It is worth pointing out that the microwave-assisted method also has widespread application in solid-phase peptide synthesis. 114,115 High hydrostatic pressure (HHP) is an emerging nonthermal treatment technology, which refers to the use of water as the medium and the pressurization treatment of 100−1000 MPa under the condition of 25−60 °C.…”