Production of fermented sweet potato flour using indigenous starter cultures

The present study develop various microorganisms for starter culture purpose from fermented sweet potato and used the developed starters in the fermentation of sweet potato and products for consistent quality product with improved hygiene. Sweet potato was purchased from different markets and microorganisms were isolated and developed as starters. Comparative studies on different starters for the fermentation of sweet potato for 48 h were investigated. The microbial count of the starter cultures increased as fermentation period increased from 6.06 to 9.14 cfu/ml, the pH reduced from 5.49 to 3.28 while the total titrable acid increased from 0.001 to 0.04. Amongst the various starters used, the use of the mixed cultures (combination of lactic acid bacteria L201 and yeast 601A) as starter cultures in the fermentation of sweet potato for 48 h had the best attributes in terms of texture, flavour, rate of fermentation and consistency when prepared as meal (bolus). The mineral analysis showed that most of the mineral content in the sample increased after fermentation for calcium (Ca) 2043.9 to 2177.5 ppm and Mn 6.29 to 26.32 ppm. The functional properties of the fermented sweet potato flour produced showed moisture content of 10.42%, water absorption capacity of 1.77 g/g and swelling capacity of 86.67%. Key words: Starter culture, fermentation, sweet potato, mineral analysis, functional properties.