Oct 1, 2009

Seaweed wines are more healthy but have antioxidation issues

Green seaweed (chlorophytes) and red seaweed (rhodophytes) are commonly consumed as vegetables in Eastern Asian countries. The sulfate polysaccharide in seaweed is believed to have functional properties related to health, including thrombus prevention, antiviral and anti-cancer activity.

Scientists at the University of Georgia and elsewhere wanted to produce healthy wines using green and red seaweed and to determine their chemical and sensory attributes. Their work indicates that seaweed wines might be better consumed fresh because they eventually lose their antioxidation activity.

In experiments, both green and red seaweed were heated at 90 C for 1 hour and adjusted to an acidity of 0.7 to 0.8 mg per 100 ml and to a range of 22 to 23 brix. Researchers then inoculated the seaweed broths with Saccharomyces cerevisae. The broths were fermented at 22 C to 23 C. Volatile compounds from the wine samples were analyzed using gas chromatography (GC) and mass spectrometry (MS). The sulfate content of the products was monitored using the rhodizonate method. The investigators determined the sensory qualities of the samples as well as of commercial fruit wine products using quantitative descriptive analyses.

Investigators found that the alcohol content in the green and red wines was 12.7% and 12.4%, respectively. The sulfate content in the green seaweed wine was 12.6 g per ml, while that in the red seaweed wine was 14.23 g per ml. After a 12-month storage period, the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging capacity declined by 34.6% to 41.3%. The phenylethyl alcohol volatile compound levels in green seaweed wines were 54.15 ppm and 74.45 ppm in red seaweed wines. The levels of diethyl succiate were 2.59 ppm in green seaweed wines and 1.79 ppm in red seaweed wines. The levels of these compounds closely approximated the levels found in grape wines.

The absorbencies at 270 nm were 1.32 to 1.27 for the green seaweed wine, and 1.22 to 1.16 for the red seaweed wine during a 12-week storage period. The sweetness level of both seaweed wines was close to the level found in Burgundy wines. Astringent scores were lower than those found in Bordeaux wines.

Further information. Yao-wen Huang, Department of Food Science and Technology, University of Georgia, Athens, GA 30602; phone: 706-542-1092