The Effect of Fermentation Time on pH Value and Total Lactic Acid Bacteria in Purple Sweet Potato (Ipomea batatas L.)
Nurchalisah Rustan M (a*), Amran Laga (a), Muspirah Djalal (a)

a) Department of Agricultural Technology, Faculty of Agriculture, Hasanuddin University. Jl. Perintis Kemerdekaan No.KM.10, Tamalanrea Indah, Kec. Tamalanrea, Makassar City, South Sulawesi 90245
*nurchalisahrm[at]yahoo.com

Abstract

Fermentation is the chemical transformation of organic substrates by the action of microorganism-produced enzymes. Fermentation can alter the physical, chemical, and functional aspects of a substrate. The spontaneous fermentation modification technique uses the amylolytic activity of microorganisms found in the environment, such as lactic acid bacteria capable of creating starch degrading enzymes. This study aimed to identify the ideal pH value and total lactic acid bacteria (LAB) count during purple sweet potato spontaneous fermentation. The starch in purple sweet potato was modified in this study through spontaneous fermentation with 0 hours, 24 hours, 48 hours, and 72 hours. The pH value declined from 6.45 to 4.10 after 0 hours, 24 hours, 48 hours, and 72 hours of fermentation, whereas the total lactic acid bacteria (LAB) increased till 48 hours of fermentation. The total LAB concentration decreased after 48 hours of fermentation. The optimal LAB fermentation took 48 hours, with a pH of 4.25 and a total LAB concentration of 8.73 log cfu/mL.

Keywords: Fermentation- pH- Total LAB

Topic: Food Microbiology and Biotechnology