Functional Protein Concentrates Extracted from the Green Marine Macroalga Ulva sp., by High Voltage Pulsed Electric Fields and Mechanical Press

Abstract

With decreasing available land and fresh-water resources, the oceans become attractive alternatives for the production of valuable biomass, comparable to terrestrial crops. Seaweed cultivation for food, chemicals, and fuels is already under intensive development, yet efficient technologies for separation of major components are still missing. We report a food-grade process for the extraction of proteins from a green macroalga, Ulva sp., using high-voltage pulsed electric field (PEF) cell-membrane permeabilization, coupled with mechanical pressing to separate liquid and solid phases. We showed that a PEF treatment, at 247 kJ/kg fresh Ulva, delivered through 50 pulses of 50 kV, applied at a 70.3 mm electrode gap on the 140 g fresh weight of Ulva sp., resulted in an ∼7-fold increase in the total protein extraction yield compared to extraction by osmotic shock. The PEF extract of 20% protein content showed 10−20 times higher antioxidant capacity than β-Lactoglobulin (β-Lg), bovine serum albumin, and potato protein isolates. The protein concentration per dry mass in the residual biomass after PEF treatment was increased compared to the control because of the removal of additional nonprotein compounds from the biomass during the extraction process. These results provide currently missing information and technological development for the use of macroalgae as a source of protein for promoting sustainable human nutrition and health.

Advances in Extraction Methods to Recover Added-Value Compounds from Seaweeds: Sustainability and Functionality

“…However, some authors believe that PEF has a good potential in integrated seaweed biorefinery approaches, particularly as a pretreatment to disrupt biomass and facilitate extraction using other complementary technologies [ 62 ]. Postma et al [ 84 ] studied PEF on the release of water-soluble carbohydrates and proteins from Ulva lactuca and obtained the yields of <15% and 15%, respectively and Robin et al [ 85 ] showed a 20% of protein yield from the same seaweed.…”

Feasibility study of Ulva sp. (Chlorophyta) intensive cultivation in a coastal area of the Eastern Mediterranean Sea

“…was chosen as the model species as it is very common on the shores of Israel and displayed high biomass productivity in extensive cultivation offshore in Israeli waters . Furthermore, the production of proteins and starch, and biomass fermentation to acetone, ethanol, butanol, and polyhydroxyalkanoates from several Ulva species has already been demonstrated …”

Current knowledge on the extraction, purification, identification, and validation of bioactive peptides from seaweed

“…PEF coupled with mechanical pressing was employed for protein extraction from Ulva sp. An optimized protocol (see Table 2) resulted in a seven-fold increase in total protein yield (∼20% protein in the extract) when compared to an extract obtained using an osmotic shock [46]. Moreover, the PEF aided Ulva sp.…”