Culture of Five Commonly Used Acid-Producing Bacteria on Banana Pulp

A significant fraction of the bananas and plantains produced in the humid tropics are wasted due to rapid spoilage. The use of acid-producing, anaerobic fermentation may be a safe and economical way to preserve the fruit in both large- and small-scale applications. The abilities of five commonly used, acid-producing bacteria to ferment media containing ripe or green bananas were examined. Three homofermentative bacteria,Lactobacillus bulgaricus, Streptococcus thermophilus , andStreptococcus faecalis , typically reduced the pH of a puree of ripe bananas from 4.8 to about 3.5 to 3.6 in 7 days at 37C. Action on green bananas was similar, but the drop in pH was less pronounced. Very little gas evolved.Lactobacillus fermentum (formerlyLactobacillus fermenti ) andLeuconostoc mesenteroides showed active gas evolution and a significant drop in pH. About twice as much gas evolved from ripe banana medium as from green bananas. The fermented purees were spongy, soft solids floating in a clear liquor. The color was medium to light creamy brown, and the odor was pleasant. Fermented products stored at room temperature retained good appearance and aroma throughout a 1-month storage test.