Abstract:
Sesame seed was defatted and subsequently fractionated into albumin, globulin, glutelin and prolamin. The defatted flour was also subjected to alkaline
solubilization and acid precipitation to obtain protein isolate. The sesame seed
protein isolate was hydrolyzed using a combination of pepsin and pancreatin
to produce the protein hydrolyzate. The defatted flour, protein fractions,
isolate and hydrolyzate were evaluated for their amino acid profiles as well
as in vitro antioxidant and enzyme inhibitory activities. The results showed that
the glutelin fraction had higher amounts of essential amino acid (38.1%) when
compared with albumin (35.6%), globulin (31.3%), prolamin (37.1%), protein
isolate (37.1%) and protein hydrolyzate (36.7%). The defatted flour exhibited
the strongest DPPH radical scavenging activity while only the globulin, isolate
and hydrolyzate exhibited superoxide radical scavenging activity. The defatted
flour also had the strongest hydroxyl radical scavenging activity of 91.79%,
although lower than the 95.93% for the control peptide (glutathione). The
hydrolyzate had the strongest metal chelating activity (75.53%), while the
isolate had the highest ferric antioxidant reducing power. The albumin was
the most effective inhibitor of angiotensin converting enzyme and α-amylase
with values of 30.04% and 29.44%, respectively. In contrast, renin activity was
strongly inhibited (89.87%) by the isolate but acetylcholinesterase was weakly
inhibited by the hydrolyzate (16.89%) and prolamin (16.29%). We conclude
that the defatted flour and protein products are potential ingredients that
could be incorporated into foods to extend shelf-life but also with potential
bioactive properties.
