Combined effects of fermentation and germination on nutritional compositions, functional properties and volatiles of maize seeds

• The new finding of combined process in maize seeds with 4 useful microbials.
• Combined process had significant effects on the nutrition of maize seeds.
• Combined effect with B. longum had the greatest antioxidant activities.
• This is the first report of α-glucosidase inhibitor from maize extracts.
• Combined effect with B. longum could also serve as nutraceutical models.

Nutritional compositions, functional properties and volatiles of maize seeds affected by combined processes of fermentation and germination were evaluated. After maize seeds were germinated, they were fermented with 4 microbial strain; Lactobacillus plantarum, Lactococcus lactis, Bacillus subtilis and Bifidobacterium longum. The presence of B. longum could enhance the maximum nutritional compositions of fermented germinated maize seeds. Protein and vitamin E content were increased up to two-fold, total phenolic content up to three-fold, vitamin B1 up to four-fold, GABA content up to five-fold, and antioxidant activities; DPPH and ABTS+ up to two-fold after germination and fermentation processes. Total phenolic content and its positively correlated antioxidant activities (DPPH and ABTS+ radical scavenging activity), and α-glucosidase were the highest in germinated maize fermented with B. longum for 72 h. Twelve volatile compounds were generated in fermented germinated maize samples which major volatiles were pyrazine and 3-hydroxymandelic acid (sweet, corn, creamy odor).