BIOCHEMICAL-CHARACTERIZATION AND IN-VITRO DIGESTIBILITY OF THE MAJOR GLOBULIN IN CASHEW NUT (ANACARDIUM-OCCIDENTALE)

The major globulin (anacardein) in cashew nut (Anacardium occidentale) is a 13S globulin. The globulin is not a glycoprotein and is composed of at least two major types of polypeptides with estimated molecular weights in the range 18000-24000 and 30000-37000. The globulin has A(2 80nm)(1%) of 9.88, 10.56, 9.68, and 9.59 in distilled water, 0.5 M NaC l, 0.02 M sodium phosphate buffer pH 7.5, and 0.02 M Tris-HCl buffer p H 8.1, respectively. The Stokes radius of the globulin was 57+/- 3.2 A ngstrom (n=17). The isoelectric pH (pI) of the globulin was in the pH range 6.2-7.2. Hydrophobic, uncharged polar, acidic, and basic amino a cids respectively accounted for 36.4, 19.88, 25.3, and 18.4% of the to tal amino acids. Sulfur amino acids and threonine were respectively th e first and second limiting amino acids in the purified globulin. Amon g the proteinases tested, pepsin was the most efficient in hydrolyzing the globulin in vitro.