Bioactive Andean sweet potato starch-based foam incorporated with oregano or thyme essential oil

•Bioactive foams were made from sweet potato starch and essential oil.•Essential oil droplets were encapsulated into the first layer of the foams.•Oregano essential oil showed the best antimicrobial activity.•Salmonella was totally inhibited in foams with 10 % oregano essential oil.•Solubility decreased significantly in foams with essential oil.