Characterization of Vitamin B₁₂ Compounds from Korean Purple Laver (Porphyra sp.) Products

Abstract

Vitamin B(12) contents of various Korean purple laver products were determined with the microbiological vitamin B(12) assay method. Although a substantial amount (133.8 microg/100 g) of vitamin B(12) was found in dried purple laver, seasoned and toasted laver products contained lesser vitamin B(12) contents (about 51.7 microg/100 g). The decreased vitamin B(12) contents in the seasoned and toasted laver products, however, were not due to loss or destruction of vitamin B(12) during the toasting process. Silica gel 60 thin layer chromatography-bioautogram analysis indicated that all Korean laver products tested contain true vitamin B(12), but not inactive corrinoid compounds. In vitro gastrointestinal digestion experiments indicated that digestion rate of vitamin B(12) from the dried Korean purple laver was estimated to be 50% under pH 2.0 conditions (as a model of normal gastric function). These results suggest that Korean purple laver products would be excellent vitamin B(12) sources for humans, especially vegetarians.

Vitamin B12-Containing Plant Food Sources for Vegetarians

“…A substantial amount (133.8 μg/100 g dry weight) of Vitamin B 12 was found in dried Korean purple laver ( Porphyra sp. ), but seasoned and toasted laver products contain lower amounts of Vitamin B 12 (approximately 51.7 μg/100 g dry weight) [57]. In particular, when the dried purple laver was treated by toasting until the laver’s color changed from purple to green, the decreases in the Vitamin B 12 contents of the seasoned and toasted laver products were not due to the loss or destruction of Vitamin B 12 during the toasting process [57].…”

“…), but seasoned and toasted laver products contain lower amounts of Vitamin B 12 (approximately 51.7 μg/100 g dry weight) [57]. In particular, when the dried purple laver was treated by toasting until the laver’s color changed from purple to green, the decreases in the Vitamin B 12 contents of the seasoned and toasted laver products were not due to the loss or destruction of Vitamin B 12 during the toasting process [57]. In vitro gastrointestinal digestion experiments indicated that the estimated digestion rate of Vitamin B 12 from dried purple laver was approximately 50% at pH 2.0 (as a model of normal gastric function).…”

“…In vitro gastrointestinal digestion experiments indicated that the estimated digestion rate of Vitamin B 12 from dried purple laver was approximately 50% at pH 2.0 (as a model of normal gastric function). The release of free Vitamin B 12 from the purple laver significantly decreased to approximately 2.5% at pH 7.0 (as a model of severe atrophic gastritis) [57]. Edible purple laver predominantly contains coenzyme forms (5′-deoxyadenosylcoblamin and methylcobalamin) of Vitamin B 12 or hydroxocobalamin (or both) [57,58,59].…”

Antioxidant Activity of the Phycoerythrobilin Compound Formed from a Dried Korean Purple Laver (Porphyra sp.) during in Vitro Digestion

“…We could not estimate the digestion rate of the phycoerythrobilin compound due to difficulty in assaying the compound in the dried laver. Using the same digestion method, Miyamoto et al (2009) estimated the digestion rate of vitamin B 12 in the Korean purple laver to be about 50%.…”

Algae and cardiovascular health

“…As summarized by Skrov á nkov á (2011), algae are relevant sources of vitamin B 12 , with Porphyra sp. presenting the highest content: 133.8 mg B 12 /100 g dry matter (Miyamoto et al , 2009). Others reported B 12 content of this algae in the range 12.0-68.8 mg/100 g dry matter (Watanabe et al , 2002(Watanabe et al , , 2007.…”