This study aimed to investigate the riboflavin, niacin, folate and B12 content in microalgae powders. Riboflavin was determined with an ultra-high-performance liquid chromatographic (UHPLC) method after extraction and a two-enzyme treatment. Niacin analysis involved mild acidic hydrolysis, with niacin quantitated as the sum of nicotinic acid and nicotinamide using a UHPLC method. Both a microbiological (MBA) and a UHPLC method was used for vitamin B12 quantification as a cyanocobalamin (CNCb1) and UHPLC-mass spectrometry was used to confirm the vitamin B12 form. Total folate was determined both with MBA and as a sum of the vitamers with a UHPLC method after extraction and tri-enzyme treatment.
The riboflavin and niacin content varied from 21 to 41 mu g/g and 0.13-0.28 mg/g, respectively, in Chlorella sp., Spirulina (Arthrospira sp.) and Nannochloropsis gaditana powders. Chlorella powders were, on average, richer in total folate (19.7 mu g/g) than Spirulina powders were (3.5 mu g/g). The sum of the folate vitamers determined with UHPLC matched better with the microbiological total folate content in Chlorella than in Spirulina powders. Pseudovitamin B12 was the predominant form over active vitamin B12 in Spirulina powders, whereas Chlorella sp. and N. gaditana powders solely contained active vitamin B12 up to 2.1 mu g/g.
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