Barfoed’s test is used for distinguishing monosaccharides from reducing disaccharides. Monosaccharides usually react in about $1-2$ minute while the reducing disaccharides take much longer time between $7-12$ minutes to react with the reagent. Brick red color is obtained in this test which is due to formation of cuprous oxide

Barfoed's test is basically used for detecting the presence of monosaccharides.