In vitro human gastro-intestinal enzyme digestibility of globulin isolate from oil palm (Elaeis guineensis var. tenera) kernel meal and the bioactivity of the digest

Globulins are the major seed storage proteins (41%) present in oil palm kernel. The study describes the
ex vivo digestibility of globulin isolate prepared from oil palm kernel meal. The bioactivity and nutritional
value of the ex vivo digest of globulin isolate was also investigated. Globulin isolate (85% protein content)
was prepared by a salt extraction method and its digestibility was studied using human gastroduodenal
juices (HGDJJ). By SDS-PAGE analysis it was evident that the globulin isolate was completely digested by
HGDJ. Easy digestibility of a dietary protein is essential from the nutritional point of view. In the present
ex vivo stUdy. the digestion profile and degree of hydrolysis of globulin isolate were observed to be
comparable with that of casein. RADVFNPR and KLPLVERIP were the two peptides identified by MS/MS
analysis in the final hydrolysate. By pepsinolysis. it was evident that the novel globulin protein preparation
was devoid of pepsin resistant proteins that are otherwise considered to have allergenic potential. The ex
vivo hydrolysate exhibited potent ACE-inhibitory activity (IC50 µg ml-1 and anticancer activity against
human colon epithelial cancer HT-29 cells and hepatocarcinoma HepG2 cells. Easy digestibility.
bioactivity, the presence of nutritionally important free essential amino acids and non-protein amino
acids (gamma-aminobutyric acid and citrulline) in the gastrointestinal digest suggests that the globulin isolate
prepared from palm kernel meal can be used as a nutraceuticaL protein for food applications.