[Determination of riboflavin in foods]

The author examined the conditions under which the lumiflavin method may be used for the determination of riboflavin. Neither the presence of various cations and anions, nor the presence of cellulose, starch and protein exerted any effect on the oxidation with potassium permanganate. The riboflavin losses increased when potassium permanganate was used at a concentration of more than 2%. The losses were considerably lower it the purification of the extracts by means of potassium permanganate was performed after photolysis. The most favourable results were obtained when the extracts were shaken with chloroform prior to photolysis to eliminate interfering substances. These findings were corroborated by comparative analyses on 3 standard samples.