2.1. Materials
Seeds lupin (L. albus L.) of a local variety (Rubatab) were purchased from a local market (Omdurman, Sudan). Fresh cow milk samples were obtained from the University of Khartoum Farm, Shambat, Sudan. Rennet tablets were obtained from Christen Hansen's Laboratorium (Copenhagen, Denmark). Unless otherwise stated all chemicals used in this study were of analytical grade.