Phenol content and antioxidant activity in seaweed fermented with lactic acid bacteria

Antioxidants and antimicrobials are rich in seaweed. Seaweed has been used as food for a long time and the potency to be used as a functional food. One of the most versatile foods is fermented beverages. Fermentation can increase the amount of antioxidants. This study aims to determine seaweed (Gelidium sp. and Eucheuma cottonii) extract fermentation with lactic acid bacteria (LAB), namely Lactobacillus plantarum and Lactobacillus acidophilus, as a starter on phenol content and antioxidant activity. The method used was an experimental laboratory. The seaweed was obtained from Yogyakarta. Seaweed extract was given a LAB starter and then fermented for 24 hrs. The samples were analyzed before and after fermentation in parameter reducing sugar, TPC, LAB viability, pH, phenol content, and antioxidant activity IC50 tests. The result showed that both in Gelidium sp. and Eucheuma cottonii, reducing sugar does not change before and after fermentation with the LAB starter. Fermentation could increase the TPC, LAB viability, phenol content, antioxidant activity IC50, and lower the pH sample. Eucheuma cottonii fermented with L. acidophilus gives the best characteristic of antioxidant.