1. Svenson J, Smallfield BM, Joyce NI, Sansom CE, Perry NB: Betalains in red and yellow varieties of the Andean tuber crop ulluco (Ullucus tuberosus). J Agric Food Chem. 2008 Sep 10;56(17):7730-7. doi: 10.1021/jf8012053. Epub 2008 Jul 29. [PubMed:18662012 ]