Germination as a process to increase the polyphenol content and antioxidant activity of lupin seeds (Lupinus angustifolius L.)

In this work, the effect of germination of lupin seeds (Lupinus angustifolius L., c.v. Zapatón) on bioactive phenolic compounds as well as on the antioxidant activity was studied. Phenolic compounds were analysed by HPLC-PAD-ESI/MS. The antioxidant activity was determined by spectrophotometry, evaluating the free radical scavenging activity of the samples. Germination produced significant changes in flavonoids and non-flavonoid phenolic compounds. In the analysed samples, isoflavones, flavones and dihydroflavonols in free and conjugated forms were identified. The results obtained indicate that germination modifies the quantitative and qualitative polyphenolic composition of lupin (Lupinus angustifolius L.) seeds during the different days of the process, with a significant increase of flavonoids. An increase in the antioxidant activity was also observed as a consequence of the process. Germination was shown to be a good process to increase the phenolic content of lupin seeds as well as their antioxidant activity.