Seaweed Extraction for Tailored Meat Products

“The more, the better,” is no longer some people’s philosophy when it comes to meat. On the contrary, in recent years, medicine and science have highlighted some of the negative health effects of meat overconsumption, especially from a cardiovascular standpoint. [1]

Seaweeds possess biocompounds such as marine algae polysaccharides, phenolic compounds, pigments, fatty acids, proteins, peptides, amino acids, vitamins, and minerals which can improve meat in ways that enrich its benefits while mitigating its drawbacks. [2] By extracting and infusing seaweed into meat formulations, scientists believe they can produce new, better forms of meat products. Seaweed may, for example, improve shelf life, color, and nutritional value.

Some traditional extraction methods have inherent flaws, such as the need for large quantities of organic solvents or exposure to high temperatures over prolonged periods of time potentially degrading thermally fragile compounds. Therefore, scientists have explored alternative, novel, green extraction methods such as microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), enzyme assisted extraction (EAE), pressurized liquid extraction (PLE), and supercritical fluid extraction (SFE).

Researchers from Spain have provided a review of these methods’ efficacy in extracting some of the aforementioned biocompounds. [2]

UAE

Ultrasound-assisted extraction (UAE) has shown promise with lower solvent consumption, shorter extraction times, mild operating temperatures, and simplicity. It has been used to extract biologically active polysaccharides from seaweed with great results in terms of the compounds’ antioxidant and antimicrobial activities and yields. [3] Moreover, bolstering UAE with enzymatic treatment improved yield and was the best strategy for targeting sulfated polysaccharides with anticoagulant and antioxidant properties. [3]

UAE was also noted to be efficient in obtaining pigments of seaweeds when compared with classic Soxhlet extraction. [4] When applied to proteins from marine algae, UAE has been shown to reduce extraction time nine-fold compared to conventional methods. [5]

MAE

Microwave-assisted extraction (MAE) advantages are reduced time, energy, and solvent consumption, in addition to better heating control.

One group of researchers optimized the extraction conditions for polysaccharides from microalgae (Sargassum thunbergii) at microwave power of 547 W for 23 min at 80 °C and sample-to-solvent ratio of 1:27 g/mL. [6] Another group determined optimal conditions for polysaccharides (from Ulva prolifera) using 500 W for 15 minutes at 150 °C at a ratio of 1:20 g/mL. [7]

Citing Yuan et al [8], the authors explain that “The recovery of phenolics from Lessonia trabeculate, using MAE yielded 74.13 GAE [gallic acid equivalent] mg/100 g dry seaweed (d.s.) in an extraction time of 15 min, while with conventional extraction and a longer time interval (4 h) only 49.80 GAE mg/100 g d.s. was reached.”

Pinning down the sweet spot for microwave power has proven key in the optimal extraction of polyphenols as excessive power can degrade them. MAE has also proven to be a viable option for pigments from marine algae.

EAE

Enzyme-assisted extraction (EAE) employs enzymes with hydrolytic powers to disrupt cell structures, “favoring the release of the desired bioactive.”

EAE has outperformed traditional, acid-assisted extraction methods in the extraction of polysaccharides, proteins, or phenolics from seaweeds. The authors cite enzymes including Viscozyme, Celluclast, agarase, xylanase, amyloglucosidase, Neutrase, and Alcala. Combining this method with microwaves may prove synergistic for extraction outcomes.

PLE

Pressurized liquid extraction (PLE) “applies high temperatures (up to 200 °C) and pressures (up to 200 bar) using low solvent volumes, which favors rapid extraction of the desired compounds.” Interestingly, in a study on PLE of seaweed fatty acids, solvent choice affected the type of fatty acids extracted [9]; ethyl acetate favored long-chain fatty acids, while polar solvents like ethanol provided a superior ratio of polyunsaturated fatty acids. Temperature (80 °C–160 °C) did not affect the fatty acids, however.

SFE

No list of green extraction methods is complete without supercritical fluid extraction (SFE). With carbon dioxide (CO₂), employing co-solvent ethanol boosts recovery of phenols and carotenes while increasing pressure boosts antioxidant capacity. [10]

Overall, these extraction methods can help producers target seaweed compounds for “enhancing [meat] shelf-life, nutritional, textural, organoleptic, sensorial and health-promoting

properties.” [2]

References:

1. Al-Shaar L, et al. Red meat intake and risk of coronary heart disease among US men: prospective cohort study. BMJ. 2020;371:m4141. doi:10.1136/bmj.m4141. Impact Factor = 30.223; Times Cited = 7 (Semantic Scholar)
2. Gullón B, et al. Seaweeds as promising resource of bioactive compounds: Overview of novel extraction strategies and design of tailored meat products. Trends in Food Science & Technology. 2020;100:1-18. Impact Factor = 11.077; Times Cited = 25 (Semantic Scholar)
3. Fidelis GP, et al. Proteolysis, NaOH and ultrasound-enhanced extraction of anticoagulant and antioxidant sulfated polysaccharides from the edible seaweed, Gracilaria birdiae. Molecules. 2014;19(11):18511-18526. doi:10.3390/molecules191118511. Impact Factor = 3.267; Times Cited = 38 (Semantic Scholar)
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