Germination as a process to improve the antioxidant capacity of Lupinus angustifolius L. var. Zapaton

Abstract

Antioxidant capacity, measured by glutathione (GSH), superoxide dismutase-like activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), trolox equivalent antioxidant capacity (TEAC) and inhibition of lipid peroxidation in unilamellar liposomes of egg yolk phosphatidylcholine (PC) has been evaluated in raw and germinated lupin seeds (Lupinus angustifolius L. var. Zapaton) for 2, 3, 4, 5, 6 and 9 days. The content of antioxidant vitamins E and C has been also studied. The tripeptide GSH kept invariable for the first 5 days of germination and suffered a decrease of 20 and 78% after 6 and 9 days, respectively. During lupin germination, SOD-like activity increased slightly whilst PRTC doubled the amount after 9 days. TEAC values changed slightly up to 5 days of germination but after 6 and 9 days a significant increase (25 and 28%, respectively) was found. The oxidation of PC was inhibited by germinated lupin extracts and 9-day germination seeds provided the highest inhibition. Furthermore, germinated lupins provided more vitamin C, vitamin E activity and polyphenols than raw seeds, and the largest amounts of these bioactive compounds were found after 6 days of germination. Therefore, germination of lupin seeds (Lupinus angustifolius L. var. Zapaton) seems to be a good process to enhance their antioxidant capacity.