Hey I just had a recent science experiment with benedict's solution and egg whites. I would assume there would be no monosaccharides present, however, the test yielded a purple colour. From searching online and my previous knowledge, purple is negative result, but perhaps a positive result? I was thinking when the Cu (II) ions become reduced they turned red which blended with the blue solution to form a purple colour, I discovered the composition of Egg whites had 4% glucose.

 

Do you think this is a reasonable hypothesis? I thought about this as a contamination issue, however, there have been many results which other individuals yielded similar results, and my whole class had the same results also. Therefore, any suggestions to why a BENEDICT'S TEST ( not biuret) would yield a PURPLE colour, and would this be a negative or positive result?

 

-Minh

I too have had purple results with benedicts and albumin.

Where/how did you find the information that the albumin had glucose?

Have you tested had purple results with any other proteins?